Interviewee: Dr. Robert Gilruth

Interviewers: Dr. David DeVorkin, Ms. Linda Ezell, and

Mr. Martin Collins

Date: May 14, 1986


DR. DEVORKIN: This is our second session with you, and at the end of the last session, I'd gotten up to your graduate years, and you did talk just a bit about your going to the NACA. There were, however, a number of things still in your graduate years that we wanted to complete in this session, having to do with your contact with the Roscoe Turner competition in the National Air races, and with Jean and Jeanette Piccard. I thought we would start with your contact with Jean Piccard -- his influence on you and on others at the University of Minnesota. Let's start by talking about ballooning and the Piccards.

DR. GILRUTH: I had just been selected to receive a research fellowship, which was a way that, in the depression time, a person could go to graduate school, and earn his own way. I had to work, I think it was ten hours a month, for which I got $50, and I could live on that in those days. You could rent a room, a furnished room, for $10 a month, and that left you money over to buy cigarettes and your food, if you smoked Bull Durham, that is, which was five cents a pack.

    I was quite happy to have something that good. But I was doubly lucky because it was right at that time that Dr. Piccard was picked up by the university to be a professor there, on lighter than air flight and technology.

DEVORKIN: I know I asked you a bit about this last time, about how Piccard came to Minnesota, of many possible places. Was there an interest in ballooning at Minnesota before he came?

GILRUTH: I worked on a balloon project before he came. But that was the only thing I know of, and that was a target of opportunity, because Ackerman happened to have this old Navy balloon, and he said, "What can I do with it?" He thought, "Well, let's measure the heat constant" for a hot air balloon and so on and so forth, so that was my research project.

    When Piccard came, he looked at what I was doing and said, "It's no good." He didn't ever mince any words. Of course that didn't make Ackerman like him. Ackerman didn't like him very well and he didn't like Ackerman.

DEVORKIN: To your knowledge, was Ackerman the one who brought Piccard?

GILRUTH: I wouldn't be surprised. I'm quite sure that he wanted Piccard on his staff because Ackerman was a promoter as well as a teacher and getting Piccard there was very good for the university. He was so well-known. You couldn't walk down the street with him without everybody turning around and looking at him and recognizing him. He was so distinctive looking, he was tall, had all of his hair tousled and everything, you know. He was quite a character, and a very nice man.

DEVORKIN: Just before we started taping, we asked you about the Century of Progress balloon flight in Chicago in 1932. You said that you actually attended it.

GILRUTH: No, I misled you. I didn't attend the balloon flight. I attended the Century of Progress Exposition, but I do not recall a balloon flight, or even knowing about one.

DEVORKIN: Because that was, of course, Piccard's great first involvement in ballooning in the United States. I'm wondering if you knew Piccard before he came.

GILRUTH: Yes, I knew of him, but I must not have gone to the Exposition at the time he did that because I didn't know about it. Somehow I missed it, living in Duluth and all that.

DEVORKIN: You came to work for him then, on part of this working research fellowship.

GILRUTH: That's right.

DEVORKIN: What were your first contacts with him after he told you that what you were doing was all wrong?

GILRUTH: Well, I was just about finished with the work on the balloon. I had to write up the data and so on. Of course, I did lots of things -- I was a lab assistant and I corrected papers and things like that, when I quit working on the balloon. But Piccard had a few projects for me. He had me design a valve for a pressure cabin of an airplane. He was very interested in airplanes flying higher. He said they'd be out of the thunderstorm belt, the air would be thinner, and you'd be able to go faster. He believed it had all kinds of advantages and he was right.

    He foresaw this and he said, "People worry about how you have a valve, how you keep the pressure up. It's very simple." He then told me the idea he had for a pressure regulator.

    But he was a showman, too. He was like Ackerman. He was a real showman. He had me rig up this valve that would discharge into a container of water so you could see it bubble. He had a balloon that showed it to have a fixed volume, and then he had this go through this valve, and as he varied the pressure, it showed that it regulated it, and he could stand up in front of an audience and show how it regulated, so that was one thing I remember I did for him.

DEVORKIN: He had a design for the valve and he wanted you to make it, or did he ask you to actually be involved in the design?

GILRUTH: Well, it was not a valve that you would use in an airplane, it was just a valve to show that you could make a valve that would regulate the pressure. It was self-regulating.

DEVORKIN: Were you given a certain degree of -- ?

GILRUTH: Oh, I had to find the materials for it, you know, out of the scrap bins and everything, because those were depression days. Nobody had any money. The university didn't really have any money either to do things with.

DEVORKIN: Who were his audiences that he would show this to?

GILRUTH: He was always talking to groups of people, citizens' groups some of them. In Minneapolis - St. Paul, I think there were lots of clubs and organizations who always wanted to hear Dr. Piccard talk.

DEVORKIN: Do you ever remember any interest from General Mills? Of course they later became very much interested.

GILRUTH: General Mills was always in the background. They helped many times with funding for things that the university did.

DEVORKIN: So they were generally friends with the university.


DEVORKIN: So this was one part of many types of support they provided?

GILRUTH: That's right.

DEVORKIN: I see. That's quite interesting.

GILRUTH: Yes, General Mills did give their support.

DEVORKIN: Did you ever assist in the demonstrations themselves?


DEVORKIN: I see. It was all Jean Piccard.

GILRUTH: It was all Jean Piccard.

DEVORKIN: Did anything ever go wrong that was memorable?

GILRUTH: No, not that I know of. He was conservative.

MARTIN COLLINS: Given Piccard's bent for showmanship, what was attractive about the University of Minnesota to him? What facilities there intrigued him?

GILRUTH: Well, it was the Great Depression and it was a job.

LINDA EZELL: Didn't he come from MIT, isn't that where he was before?

GILRUTH: No. I don't know, I believe he came from Europe. He worked for a chemical company. He built blasting caps. I remember now.

EZELL: He worked for Hercules.

GILRUTH: He used blasting caps on everything. It was great for me, because it wasn't too long before I was using igniters on all kinds of spacecraft. When I went to Wallops Island at Langley Field, it was the beginning of the missile technology, using blasting caps and things like that to make things happen.

DEVORKIN: After you worked with the valve, did you do other things with Piccard?

GILRUTH: I did do various chores for him, but I don't remember what they were.

DEVORKIN: To your knowledge, did he ever develop at that time more of his stratospheric gondolas? Because I know he wanted to, through the late thirties, continue with his gondola work.

GILRUTH: Well, you know --

DEVORKIN: He couldn't get support..

GILRUTH: The first telemeter that I know of was built as one of his projects. A good friend of mine who now lives up in Washington built the first telemeter that sent down the temperature and pressure from the cellophane balloon that was launched out of the University of Minnesota stadium, and I have some pictures of that, too. I think I can find them.

DEVORKIN: These were unmanned?

GILRUTH: Oh, of course.

DEVORKIN: What is your friend's name?

GILRUTH: Bob Silliman.

EZELL: You mentioned him last time.

GILRUTH: Robert M. Silliman.

DEVORKIN: I wanted to ask about the Pleiades, the multi-balloon chain system?

GILRUTH: That was not in his mind when I was there with him.

DEVORKIN: Not yet.

GILRUTH: That came later.

DEVORKIN: Did Jean Piccard ever speak of his brother Auguste?


DEVORKIN: I'd be interested to know if you could relay the general flavor of how he regarded his brother's work, and why his brother went back to Belgium?

GILRUTH: I don't remember, but he always spoke fondly of his brother, always called him "my bruzzer."

DEVORKIN: He kept a very thick accent.

GILRUTH: He had a thick accent but he was very understandable.

EZELL: You said in the last session not to forget his wife.

GILRUTH: Oh yes, Jeanette. Jeanette was an American girl who married him. She was very bright, had her own doctor's degree, and was at least half of the brains of that family, technical as well as otherwise. She was the one who was the pilot of the manned balloon, because she took the training and got the license, so that they were able to go up to the stratosphere. She did a fair amount of lecturing on her own, and outlived her husband.

EZELL: Did she lecture at the University of Minnesota?

GILRUTH: No, he was the professor. She used to be there, though, and Jean Piccard, if he was giving you an exam and you weren't doing it right, he'd say, "Oh, non, non, no," and she'd say, "Jean, no, bad, you know." She was always in the room when he was lecturing or otherwise, almost always. She was something. She was good.

DEVORKIN: How do you feel your contact with Jean Piccard changed your own views about things, if any? Did he have an influence on your own career?

GILRUTH: Of course he did. It's hard to know how much, but certainly when you know a man as prominent as he was, you could see how he thought and how he worked. I learned many things from him, ways of looking at problems.

DEVORKIN: Can you describe that?

GILRUTH: No, not very well, but I do feel that he did influence me. He had a way of simplifying things, in talking about things, that were simpler than many other people did.

DEVORKIN: Well, if we could take the case of the valve, if you could remember, he gave you the overall design sense and you had to work out the details?

GILRUTH: Well, let me tell you something right off, I don't think that's a good example, because it was obvious to me that the valve would not be a problem for a stratospheric cabin, that it would be easy to regulate that pressure, and he wanted to demonstrate how it would work, so I built it. There wasn't any big thing about how you did it. It was obvious. It was good for the audience but it wasn't a real tough thing about the going into the stratosphere.

DEVORKIN: Was he aware of the fact, or did he compensate for the fact or ever discuss the fact that the valve would operate at standard temperature and pressure on the surface of the earth in one way, but possibly making it work in the stratospheric under very cold conditions would be very different?

GILRUTH: Actually, the valve could be on the inside of the cabin. It didn't have to get cold, because the pressure you're regulating was the cabin pressure. When it got high, the valve would open a little and let air out, and when it was low, it closed, and you had a pump that was always feeding in there. So it was a simple thing to do. But the general public didn't know that, and he showed how simple it was. It was really a perfectly good thing to do. It just happened to be easy.

COLLINS: Is there an example you could draw on in your early days at NACA of the Piccard philosophy?

GILRUTH: Oh yes, the work on the gondola, learning about the gondola and how he managed it, was just 20 years ahead of designing the Mercury capsule. Of course we had a heat shield. It was tougher and it had to go through the speed of sound while still in the atmosphere. So there were a lot of different problems. I learned a lot from him about the internal regulation of the manned gondola and what a man needed. I got a letter from him after John Glenn's flight, in which he expressed his feelings about pressure suits. When Glenn sat in the capsule on the ocean for a while before he was picked up, he sweated a lot -- of course just because it was hot, not because he was worried. Piccard read somewhere about that, and he wrote me a letter and said that making a man wear a pressure suit was a bad thing to do. He said, "We never wore pressure suits in balloons."

    You see, if he'd been in my position, he would have had Glenn wear a pressure suit, because we were always afraid we'd lose the pressure. That did happen to the Soviets, and they lost a crew that way. We never had one like that, but we could have.     He was against pressure suits and he had to write me a letter about it.

DEVORKIN: When you were working for Piccard, were there other graduate students working for him as well?

GILRUTH: Yes, my first wife worked for him, Jean Barnhill. That was before we were married. She had another of these fellowships, and she had the job of building this cellophane balloon that was used for this first flight there at the university. She actually cut out the cellophane gores and glued them together with scotch tape. Cellophane and scotch tape had just been invented by General Mills and with clever women and scotch tape you can build almost anything.

DEVORKIN: Was she involved at all in trying to decide the best design for the catenary using a different material or anything of that sort?

GILRUTH: No, she was just purely a person who put that thing together the way he said. Of course she was there during the launching, and did a lot work of helping him fly it.

DEVORKIN: This was still about 1936, 1937?

GILRUTH: I think it was '35.

DEVORKIN: That's even more interesting to me because this was the time when the Explorer 1 and 2 series, '34, '35, '36, a series of flights took place. That was when the Army Air Corps and the National Geographic got together and flew those huge balloons from --

GILRUTH: Yes, I remember that Piccard was very, very hurt by the National Geographic that would not give them a dime, and they gave so much to these other people. There was a colonel I can't remember his name now --

DEVORKIN: Anderson, and a Major Kettener?

GILRUTH: No. There was one that lost his life or almost lost his life. I can't remember those things anymore.

DEVORKIN: I know that Jean and Auguste Piccard were initially involved, and then somehow lost contact. Did he ever talk about it in detail?


DEVORKIN: You just have a recollection that he was hurt that he was left out.

GILRUTH: Both he and Jeanette said that they were discriminated against by the National Geographic. That's not a good word. They were not aided in any way by the National Geographic, and they felt it was not really warranted. They felt they should have gotten some help from them.

DEVORKIN: They never said why.

GILRUTH: No, he didn't say why, but they certainly didn't feel they'd been handled fairly.

DEVORKIN: They never talked about the design of the gondolas or the design of the balloon?

GILRUTH: If they did I don't remember. They had their own design of the gondola. And the balloon was a balloon that they inherited some way. It was a balloon already built.

DEVORKIN: Yes, it was rubberized cloth.


DEVORKIN: It certainly wasn't cellophane.

GILRUTH: No, no. That's right. They inherited that somehow. I don't know how they got it, but that's what they used for their flight. And they used hydrogen.

DEVORKIN: In the first one, that's right, but they did use helium in the second one. What's important, however, is if you have any recollection of how the Piccards thought about it or if they criticized the design in any way.

GILRUTH: I don't remember.

EZELL: I read yesterday some WHO'S WHO type article about Jean Piccard, and he had listed in there that he was a consultant for a while to the Manned Spacecraft Center.

GILRUTH: Mrs. Piccard was.

EZELL: Mrs. Piccard was, in what way?

GILRUTH: Well, I hired her.

EZELL: I thought you might have.

GILRUTH: I hired her after I went and made a speech in Minneapolis, and Mrs. Piccard was there in the audience. I was so glad to see her. She was fine. She was about, I guess, ten years younger than I am now.

EZELL: This was probably early sixties?

GILRUTH: Yes, it would have been. It was just about like '61, '62, something in there. Jean had died. She was living alone in a house there, in Minneapolis, and I asked her if she would like to consult for us. She said, "I don't know", and I said, "Well, you know a lot about the stratosphere and about flying, you were a balloon pilot in those pioneer days, you can talk about our program to groups of women and groups of men, just get the word to them about what it is we're doing. You're famous, the people still remember what you did, and it can help our program."

    So she said, "Do you realize how old I am, Bob?" and I said, "Well, I think you're fine, you've got lots of years left." So she kept her house, but she used to be away from it for protracted times. I think she roomed with another lady down in Houston. I don't really remember that much about that. But anyway, she was a big help to us, but later on she got very wrapped up in religion and that really took over all of her efforts as she got older. Somehow or other, she drifted away, and we didn't see her any more. But we did keep in contact, Christmas cards and things like that. Finally it was evident from the Christmas cards that she was really getting old, much older, and that's about all I remember now about that.

DEVORKIN: Did Jean Piccard ever express in his lectures what his particular interests were in getting into the stratosphere? Was it manned flight or was it, as it was for his brother, an interest in cosmic ray research?

GILRUTH: His interest was very great in cosmic ray research, and he had that kind of instrumentation on board that cellophane balloon, and Bob Silliman built the telemeter that recorded what that was. He might remember something about that. But I don't. I didn't know anything about that myself.

DEVORKIN: Do you recall at all if that was an interest generally in Minnesota, or was it something that Jean imported as an interest? Were physicists or others interested in using balloons other than Ackerman as you mentioned?

GILRUTH: I don't think their impetus came from anywhere else, but I don't know that for sure. I didn't know anyone who was --

DEVORKIN: Let's finish up the Piccard discussion by asking you to expand if you wish on the personalities of both, Jean and Jeanette Piccard. You've already given us some nice profiles, but how easy or how approachable was Jean Piccard on a professional level with his colleagues? How well did he get along with the other colleagues at the university? What would you like to say about him in that regard?

GILRUTH: I really can't answer your question about how he got along with his peers there. I think some of them felt that he was taking advantage of his scientific looks, and was really not doing anything very important.

DEVORKIN: His scientific looks being actually his physical appearance?

GILRUTH: His physical appearance, and he was the epitome of a scientist that didn't think anything about his hair or his clothing or anything else, just his job he was doing, the thing he was trying to do. In my opinion he was a very fine man. He had a lot of boys, he and Jeanette, and they were fairly young boys when he was at the university. I think he had about, I don't know how many there were. It seems like there was a dozen, but--

DEVORKIN: You mean his sons?

GILRUTH: His sons. He had lots of sons, their sons.

EZELL: I remember four but there might have been more.

GILRUTH: I remember eating breakfast when we went to St. Cloud for a balloon launching, eating breakfast in the dining room of the hotel, and he had all these boys sitting around the table with him and Jeanette, and I remember the youngest one took the corn flake box and dumped it on his father's head. Of course, Piccard just brushed it off his head and said, "No, no."

DEVORKIN: Was there anything stronger than that?

GILRUTH: Not much, no. He was very gentle. He loved his boys, and he thought boys would be boys, I guess. I don't know.

DEVORKIN: Who ran the family, Jeanette or Jean?

GILRUTH: Oh, Jeanette, Jeanette.

DEVORKIN: Do you think we can move on to your 1936 summer work for Barlow?

GILRUTH: Yes. I worked for both Piccard and Barlow; it was sort of mixed in together.

DEVORKIN: Were they really? Can you describe -- is there a way to distinguish how you divided your time?

GILRUTH: Well, when I was working for Professor Barlow on the Roscoe Turner airplane, I worked steadily on that, all I could, and I can't tell you exactly. It was during the summer, and I don't think I was taking half a day with Barlow and half a day with Piccard or anything like that. I think I worked a steady stretch for Barlow. All I can remember are the kinds of things I did for him. I can't remember the dates, anything like that.

DEVORKIN: No problem. Let's talk about the specifics of what you did.

GILRUTH: Well, Roscoe Turner was a friend of Barlow's. Barlow had fixed an earlier airplane that had flutter of the aerolones, and that made him important to Roscoe.

DEVORKIN: How would you characterize Barlow's background? What was he?

GILRUTH: He was an aeronautical engineer, a graduate engineer that got a professorship. He was not a full professor, he was an instructor, at that time, and he worked for Ackerman.

DEVORKIN: I see, he worked for Ackerman.

GILRUTH: He worked for Ackerman, and Ackerman was also a designer. But Barlow was a designer that used all kinds of things that he learned in American schools. Ackerman came from Russia, and it was a little hard to understand some of his designs. Roscoe had a connection with the Pratt and Whitney Company, and they had offered him an engine for a dollar, a brand new engine for a dollar. If he would put it on an airplane and enter the Thompson race, and so he went to Barlow and said, "Look, I've got this engine, and I think I know how I can raise some money to have an airplane built, if you'll design it."

    Barlow was just delighted. It was summer and he had some time, and he loved to design airplanes, and he decided to get all this cheap help, and so there was a job for three or four of us here, and I can remember their names. Herman Pusin was a fellow who later went and became a vice president of Martin Company, a Jewish boy, very bright, and gee, I'm not so good on the others. There was another one, Jack Aitken who was a draftsman. He was an engineer but he did mostly drafting, and he went to work for an airline. He went with Pan American later.

    And there was another boy that was a draftsman, named Johnny Stuck, who went with General Dynamics later. We all worked there, and I did a lot of different things. I tested a wind tunnel model in a 4 x 4 wind tunnel that Minnesota had. I designed a lot of the Turner airplane. I was hired as a stress analyst, but I did a lot of the design. It was the most interesting part for me. Stress analysis wasn't hard to do but it was just a bunch of figures, you know, like accounting or something, but designing was something else. I went to the library and I looked up all the old Snyder Cup racers and their records. I also studied the Deutsch Mueller Cup Races that were held in Germany. I studied all those old airplane designs, and also the latest things in the magazines on new designs.

DEVORKIN: Is the Minnesota Library pretty good on this?

GILRUTH: Pretty good, yes. As good as any, I think, in those days.

    So I did my homework, and I think I helped Barlow a lot, because I don't think he would have taken the trouble to make sure that this airplane was not going to be grossly different in stability and control than other airplanes of the same kind.

    And so, I got to do a lot of things in airplane design and in stress analysis that helped the project and must have helped me a lot in later years.

DEVORKIN: How did you and your three graduate student compatriots work with Barlow? Were there weekly meetings, daily?

GILRUTH: He'd come in and work with us. We didn't have any meetings. We were all in the same little room. We worked in an old swimming pool actually. They drained the pool and they moved a bunch of benches and desks down in there, and we worked in this old swimming pool. It was in the armory of the university, the old armory.

DEVORKIN: Does that imply that you were really crowded for space or nobody liked swimming or something?

GILRUTH: The aeronautical engineering department didn't have a whole lot of space. It was not one of the gilt-edged things like the physics department and so on. Ackerman was a promoter, and he was trying to do everything he could with the resources he had, and Barlow was working in there and he needed some place to work, so the place was perfectly good. It was out of the rain and snow and everything else. We didn't think much bad about it. We worked for 40 cents an hour, and if you were able to work enough, you could bring home $25 a week, which was pretty good.

DEVORKIN: You all pretty much worked together?

GILRUTH: We worked together and we turned out a pretty darned good airplane, and it was actually built and Roscoe won the Thompson with it a couple of years in a row.

EZELL: How did Mattie Laird's operation get involved with this design? It almost looked like it was designed by a committee, there were so many people that had an input.

GILRUTH: The Laird-Watt they called it the Laird-Watt racer. I know there was a problem getting the airplane built, and I don't know that story. I was gone. I was at Langley Field.

EZELL: So the design came from you all but the construction probably came from ...

GILRUTH: We had nothing to do with that. And there were some changes made in it. I know they put pants on the wheels and we didn't have pants on the wheels because we decided it was better without it, lower drag without it. But you had to use a certain kind of wheel that was being built then, and maybe they couldn't get them, I don't know.

DEVORKIN: You were not in on the phase where the designers and the constructors were dealing with each other.

GILRUTH: That's right.

DEVORKIN: Did any of the other people you mentioned, Pusin, Aitken or Stuck, remain and later get involved, or would it just have been Barlow?

GILRUTH: It would have been Barlow, I think, because the boys were going out, were trying to get jobs in industry in one way or another.

DEVORKIN: What kinds of reports or documents can you remember producing from this design phase, plans, working drawings, -- did you get anything down on the record?

GILRUTH: Oh yes, there were detailed drawings, wing drawings, fuselage and so forth, and there was a complete stress analysis made of that airplane.

DEVORKIN: Any conceivable chance that you'd have a copy?

GILRUTH: No, I certainly don't.

DEVORKIN: It would probably be with Barlow or with the people who constructed the airplane.

GILRUTH: It would -- I'm sure Barlow, if he were alive, would know, but I don't think he's alive.

DEVORKIN: Did he remain at the University of Minnesota?

GILRUTH: He did for a while. Then he went to Texas A and M and became head of the department there.

EZELL: He was dean of engineering.

DEVORKIN: So the chances are that if they are in his papers, they would be at Texas A.& M.


DEVORKIN: That's how one would track them down.


COLLINS: You mentioned that you had studied previous designs for this type of airplane. In what sense do you feel perhaps you improved upon or enhanced or somehow altered these previous designs to give Turner a good shot at winning this trophy?

GILRUTH: Well, I think that what we used, even though we used an awful lot of wood, made it possible to not have a whole lot of external wires and bracing. It was essentially a very simple design of a body revolution with a wing coming right out of the middle axis of the circle. The tail also, was like that, slightly elevated so it wouldn't be in the wake of the wing, get zero angle of attack, and we couldn't retract the landing gear because that was a big deal. That would have been expensive. So we had a streamlined strut down for each wheel. There wasn't a whole bunch of things, just one strut with a wheel and a streamlined wheel at that, so we had reduced the drag very, very greatly over a wire-braced gear. We used the latest airfoil sections that NACA had, and the wing was covered with plywood, which meant you could make it slick as a whistle, and the airplane had a good big engine in it. So it had every chance of being a good airplane, a good racing airplane, and it was fairly light, so it would be able to get around the closed course of the air racer.

DEVORKIN: What was the Supermarine S6-B that you mentioned?

GILRUTH: It was a Snyder Cup racer.

DEVORKIN: You improved on that?

GILRUTH: Well, yes, you looked at everything they did, and tried to see why they did it that way. They had to have great big floats, which made it hard, but they got over 400 miles an hourwith that S6-B. And a Maxi Costaldi I still remember, the Italian one, they had two 12 cylinder engines in it, one behind the other with a crank shaft, the rear one going up through the V's of the cylinders, out to the drive, to drive one propeller. I think there was a counter rotation, one drive shaft inside of another. It was a remarkable airplane.


DEVORKIN: You mentioned using the wind tunnel. I'd be very interested to know who actually constructed the air foils and the various elements that went into the wind tunnel, and worried about calibration of the tunnel and maintaining the tunnel? Was that your type of responsibility?

GILRUTH: Well, that was I. I think I helped build the model, too. What we were looking for with the model was not really anything about what the drag would be, because it was such a little wind tunnel; but for stability, to make sure that it would have static stability and things like that. It didn't really require the same precision of a model that it would if you were really trying to predict the drag. I was certainly not going to try to use that model for predicting the performance. It would be much more accurate to calculate it than go from a low Reynolds Number model like that.

DEVORKIN: Was that Barlow's opinion as well?

GILRUTH: I don't know, really. But I know that we didn't use the model for performance. I'm sure he approved of that. I learned all my performance work from him, so I just did it the way he would have done it. He was not a stability control man, and I worried more about that than he did. I wanted a wind tunnel model for that purpose.

DEVORKIN: Did he recognize that?

GILRUTH: I don't remember. I don't think he worried too much about that. The most important thing that I thought was to make sure it wasn't going to have proportions that were way out of line with what other airplanes had that were successful. I was a very pragmatic engineer, for a kid. But I had built a lot of model airplanes myself.

DEVORKIN: That's right, we talked last time about your philosophy of design a bit and I thought that was very interesting. You are very pragmatic. You were more interested in performance reliability than in how one would actually produce something of aesthetic value. You were working within design constraints probably set by the competition, but also set by prior experience.


DEVORKIN: Looking at the Supermarine and things like that did you feel that this was the most intelligent way to go about your graduate career? Were you consciously holding back from more wild designs? Can you recall ever brainstorming? Were there others who had the same sort of feeling, or was this sort of the flavor of engineering at Minnesota at that time--to be conservative and pragmatic?

GILRUTH: Well, I didn't think that I was being conservative, when I was trying to design an airplane that was going to win the Thompson Trophy Race. That was right on the frontier of aviation, and it proved to be, and I made good use of that experience when I went to work for NACA. It was very, very helpful to me. I guess it was equivalent really to a couple of years experience even though it was done while I was at school.

DEVORKIN: What was the effect of this work, and let's say your experience with Piccard, on both the choice of a thesis and on the execution of your Master's thesis at the time?

GILRUTH: Ackerman, who was head of the department, tried to talk me out of my thesis. He said, "That's too tough."

DEVORKIN: Did we talk about the thesis last time?

GILRUTH: It's wing tip propellers.

DEVORKIN: But I don't recall your saying that he tried to talk you out of it.

GILRUTH: Yes, he actually said, "That's too tough. First, it's not a very good idea, and second, it's too tough." I knew that you wouldn't put propellers at the wing tip of an airplane with a slender wing, but I was thinking of making a low aspect ratio wing with propellers at the wing tips, and this makes a little more sense. I built some fine models actually that flew quite well--rubber band models and so on -- and I ran the wind tunnel tests, on my thesis, made the model, and it's a very nice piece of work. It showed that there was some good effect, but when you got right down to it, it wasn't worth making an airplane that way, to get that rather small effect. So, after having taken this thing to the NACA, and they were quite interested in it, but they used my own data to show that it probably wasn't going to be worthwhile to use it for a type of airplane. I agreed with that. But I think it was quite useful to me, because I got well known in a hurry, when I went to NACA, because I did write this memorandum saying that this was a thing that I had done and were they interested and so on and so forth.

EZELL: You wrote the memorandum while you were a student?

GILRUTH: No, no, this was after I went to NACA. I brought it to their attention and they gave it consideration, and I agreed with their conclusions. So that was the end of that one.

DEVORKIN: Is there anything about your graduate years then that we still have to cover? I know that you graduated in December, '36. That seems to be --

GILRUTH: -- that's when I got my Master's degree.

DEVORKIN: But you took the junior aeronautical exam in the fall of '36.

GILRUTH: That's right.

DEVORKIN: I'm wondering if passing that exam and getting the call from the NACA accelerated or truncated your graduate program?

GILRUTH: I didn't know I had passed the exam until they wrote me a letter and said that I could come to work if I wanted to. I was elated. I regarded going to work at NACA as a better place to learn than going on to graduate school, because it was an absolutely fantastic place to work I thought, and I was right. It was. I just got a great lift when I heard that I'd been selected to be a junior engineer.

DEVORKIN: Is there any chance that you would have copies of the exam or your letter of appointment in your collection?

GILRUTH: No, I certainly don't have the exam. All I had was just a form letter that said, "You have been selected, report at such and such a time." It was in the next two weeks -- I graduated in December and I reported for duty January 4th. So I went home for Christmas and then went down to Langley Field.

DEVORKIN: We did talk about that in the first session.

GILRUTH: I don't remember.

DEVORKIN: One thing we left open was the question of how aware you were of America's standing in aeronautics at the time, in the mid-thirties. Were we way out front in aeronautical design, were we dragging behind the Europeans, and what was the value of going to a place like the NACA as opposed to industry at the time?

GILRUTH: All right, I would say that we'd done rather poorly in aviation. In World War II we didn't have any fighter airplanes that were American. We were just beginning to get some things of our own. We had the NC 4's that flew across the ocean and we had Lindbergh. That was a great shot in the arm for this country, when Lindbergh made his flight in the Ryan monoplane to Paris.

DEVORKIN: You meant World War I, then? When you said we had no fighters?

GILRUTH: World War I, yes. But you see, that's not so far away from 1914, '18, and then, it was just 20 years later.

DEVORKIN: You say there hadn't been that much progress in those 20 years?

GILRUTH: There was not. I can remember as a kid going to look for the airmail. They were just starting to get some biplanes, remember, the Army flew the airmail for a while and they lost a lot of airplanes. They just couldn't fly reliably. There was the Ford trimotor, and that was a great airplane -- it was still a modern airplane when I was in college.

    We had not made our mark in aviation, really, as we were to do later in World War II.

DEVORKIN: When you actually went to the NACA in January of 1937, what did you find was the perception among the people you worked with, as well as your own, for what the most fruitful and important direction to take was, in improving the capability of American Aviation?

GILRUTH: Well, I think that the thing that NACA had going for it was working on all the problems that they could. They had an engine research lab. Certainly we needed better engines. They had very advanced wind tunnels compared with other countries. They had a full scale wind tunnel, a propeller research tunnel, (nobody was thinking about jets then), a towing basin so that you could work on seaplane floats, and a variable density wind tunnel so that you could explore the effects of Reynolds Number. Best of all, they had a staff of skilled people that were dedicated in how you made the airplane better.

DEVORKIN: Let's move to some specifics. When you got your letter of appointment, did it identify who you'd be working for, the problems?

GILRUTH: No. That's a very interesting point, because I reported for duty there, and after getting finger printed and everything like that, I went to see the head of the Aerodynamics Division. There were really three divisions at the NACA at that time. There was the Aerodynamics Division, which is sort of self-explanatory, there was the Wind Tunnel and Flight Research Section and so on, and there was the Hydro Division, which was the towing basin. Then there was the Engine Lab, which was what it says.

    I was obviously an aeronautical engineer with an aviation background, so I was sent to the Aerodynamics Division.

DEVORKIN: You were sent, you were not given a choice?

GILRUTH: No, I was not given a choice. The head of that division was a fellow that looked at my background and said "Well, your experience in stress analysis and airplane design will make you particularly valuable in flight research," so he sent me to Flight Research.

DEVORKIN: Who was that person?

GILRUTH: Elton W. Miller. He was head of that. That was a big break for me, although I didn't realize it at the time, because if I had gone to a wind tunnel or some other place, I probably would not have gotten the background that was to make it possible for me to do the things I did both in aviation and space. I was working with the actual airplanes, with test pilots, and somehow or other, I found that the people that came out of Flight Research had a better chance for grasping the big picture than the people that were buried in wind tunnel work.

DEVORKIN: I'd like to ask one more question about the way you were channeled into this job. Were you aware at the time of how the NACA went about recruiting people? Was this a blind recruitment or was there a position open that had to be filled, to your knowledge? Were you simply someone who showed a certain capability passing the exam, and then were simply placed at the NACA? Was it a military kind of a model or more a model as you would have today?

GILRUTH: People who took that junior engineering exam went other places than NACA. They went to work at Wright Field, some of them, and some of them went to work at the Navy, whatever the Navy had then, but I couldn't have been happier than to go to NACA. I'm not sure, but I probably would have gone anywhere, because it was the Depression.

DEVORKIN: But that's what they gave you.

GILRUTH: This is where they wanted to send me, Langley Field. I couldn't have been happier.

DEVORKIN: Other than Elton Miller, there was nobody you knew of who was involved in determining where you would go?

GILRUTH: I'm sure he was the one. The chief clerk got me in, first. I went to the chief clerk.

DEVORKIN: Is that anybody to remember?

GILRUTH: Well, he later became a director of a new NACA lab -- the one out at Cleveland in the war years. But he was a chief clerk then, and he just decided to send me to Elton Miller, because most of the people that were being hired were going into aerodynamics. That's where most of the work at NACA was, and it was routine sort of to send me there. What Miller decided to do was not necessarily routine, but it was certainly a break for me to be sent to Flight. I didn't know that was so good at that time.

DEVORKIN: You went into flight research. Who did you end up working with and for, and what were your duties?

GILRUTH: All right, let me say that Miller called up a fellow in the flight section whose name was Floyd Thompson, and Floyd had graduated from the University of Michigan and had a tour with the Navy as a mechanic before that, so he was somewhat older, and he was head of this section that I was sent to, Flight Research Maneuvers, it was called. He came and got me, brought me back, gave me a desk, and then promptly forgot about me. Absolutely forgot about me. I knew one of the fellows there who had been an instructor of mine at junior college. We were good friends, so it was nice that he was there. I had a ride back and forth from the office.

DEVORKIN: No assignments?

GILRUTH: I had no assignments. I was just given a desk with no assignment. Being a person who didn't want to look like he didn't have anything to do, I went and got a lot of books and started studying the things I thought I was going to need to know. I read all the technical reports that flight research had written, and I tried to learn what they did and what their instruments were like. So it wasn't a waste of time at all, it was very good. But it was good that I was able to do that, and I worked hard doing that thing, and nobody paid much attention to me. Certainly Thompson didn't.

    He had an office that had a glass wall, and he could look back at all the people sitting there. There were only about six or eight double desks in the general office, and I had one of those places.

    There was only one telephone. That was in Thompson's office. You could reach through that little place in the glass wall, to get the telephone, you know -- if you had to receive a call, he'd call you. He'd pick it up and say "Yep" and then he'd yell out your name and hand it to you. It was very primitive but there was nothing wrong with it.

DEVORKIN: To the best of your knowledge, thinking back to others who were hired at the about the same time you were, give or take a few years, were they all given the same treatment? Just let them incubate, train themselves?

GILRUTH: No, I think this was just happenstance, you know. Certainly in later years when some junior engineer was sent over to my jurisdiction, I gave him something to do right away.

DEVORKIN: How did you feel about this, both at the time and then in retrospect?

GILRUTH: Well, let me tell you -- at the time I was kind of worried. I was worried, yet I hadn't done anything wrong. But I felt confident that I could do the things that they were doing.

    Finally, after about a week of this, a fellow named Hartley Soulé noticed me. He was studying the flying qualities of airplanes. He just got a whole bunch of films from one of his research flights, and he was walking with these films, and he happened to look at me. He said, "Here, you're not doing anything, how about working these up for me?"

    That was my assignment. I worked them up. I had been studying some of his reports, so I knew what it was all about.

DEVORKIN: He just said "Work them up"?

GILRUTH: He said, "Work them up."

DEVORKIN: Gee, that doesn't mean a thing.

GILRUTH: I asked him some questions, obviously, which I don't remember. I do remember what he said at first was. "Here, you aren't doing anything," which was true. I was doing something but I wasn't doing anything I'd been assigned. So I went to work on that, and it just happened that I stayed on that project. That was my assignment. It was as though the Great White Father had decided that. But as luck would have it, after about six months of helping Soulé he developed a very bad blockage in his sinus. He couldn't fly anymore. So I inherited the job of flying with the pilots on this project, and keeping the films in the instrument and taking notes and so on.

DEVORKIN: These were films that were photographing gauges?

GILRUTH: Yes, they were special instruments that used photographic film to record airspeed, altitude, rate of roll, pitch, linear accelerations, yaw and control positions. Fundamental measurements that enabled you to put together the story of just what the airplane did in response to the controls.

DEVORKIN: What was the specific project?

GILRUTH: The purpose of the project was to determine rational standards for flying and handling qualities of airplanes, quantitative criteria we needed so a designer could be sure that when he designed his airplane, it would be nice to fly, would respond crisply and accurately to the controls, and the pilot would be able to do all the things he needed to do with that airplane.

DEVORKIN: Were these the airplanes that were given over to the NACA by commercial companies for testing?

GILRUTH: Yes. We also had airplanes that were loaned to us by the military, either the Navy or the Army Air Corps, and we had some from the airlines. I remember we got one from the Air Safety Board, a Lockheed that they were worried about as not having good flying qualities, and they sent it down to us to test. We even bought airplanes for this purpose, especially if they were light airplanes that were not available otherwise and were not for NACA.

    We were trying to set up a flying quality research at the time that I got to NACA. Quantitative criteria were needed so that designers could produce airplanes that had good stability and control. We had to define flying qualities. We had to define the characteristics that make an airplane safe to fly, easy to fly, and accurate to fly.

    There were few if any standards for this. That became my job, helping Soulé do this, and when he had trouble with his sinus blockage, I took over not only working up the data but also flying on the missions.

    And then not too long after that Mr. Soulé was promoted, put in charge of a new wind tunnel, and he left the flight section. Mr. Thompson, my boss, called me in to his office and said, "Well, I know that you just came here a little while ago, and Soulé's going and you probably won't be able to handle this job and I'll have to get somebody to come over and take over the job -- but why don't you just try it for a little while?"

    Well, that was the end of that, because I stayed on and I never did get replaced. I became the flying quality expert there, and that was really quite an important project that I got into.

DEVORKIN: What were some of the most interesting or memorable plane flights that you took?

GILRUTH: Well, we started out with the Martin B-10 B, which was the first low wing monoplane bomber, and it was faster than the current American pursuit planes. We later tested a Boeing B-17 back in the days before it got the massive vertical fin. As a matter of fact, we recommended they increase the fin area on that airplane, and it was a good thing they did, because it made it a very benign airplane. It took all kinds of punishment and still came back during World War II.

DEVORKIN: These were not the initial test flights that were proof test of --

GILRUTH: No, this was research on handling qualities, and the Air Corps sent us these airplanes because they were interested in what we were doing. If they weren't, they wouldn't give us airplanes, so they had a certain type of control.

    We got one Boeing airplane from the defense services for this purpose, the Boeing B-15, which you probably do not know. That was a bigger airplane than the B-17, but only one of them was made. It was so big that the mechanics could crawl through the wing to get to the engines to work on them in flight. It was under-powered, but it was representative of a great big airplane and so it was interesting for us to test, because it had problems that were different.

DEVORKIN: The chief problem being that it was under-powered?

GILRUTH: No. That was a problem, but that wasn't a flying quality that was due to the design of the airplane. It just didn't have big enough engines. It had one problem because the wings were so long and there was so much stretch in the control cables that you could only get a little bit of aileron deflection. The pilot thought he was doing everything, but we measured both the wheel position and the deflection of the control and soon knew that all he was doing was stretching that cable.

DEVORKIN: Did you ever test any of the early Douglases?


DEVORKIN: DC 1, 2, 3 ?

GILRUTH: We tested the military version of the DC-3, and we also tested a DC-3, because it had such a quick stall. People don't realize how dangerous that airplane was regarded in the early days. With flaps up and power on, it would come right up to the stall roll off without any warning at all. We thought at that time that this was a very, very dangerous stall -- but actually, it wasn't, if you didn't let the center of gravity get so far back. There were only one or two that were lost due to the fact that they had a quick stall.

DEVORKIN: Did you recommend any design changes as a result of that?

GILRUTH: No, we just put that down as one of the things that was bad about the DC-3. It had been certified and nobody wanted to do anything about it. The main thing was to make sure that all the pilots realized that they had to be careful. It's still one of the safest airplanes there is, but it has that quick stall.

    In a normal landing, something with flaps and gear down, it's just as benign as can be.

DEVORKIN: When you found these problems about any of the airplanes, what kind of feedback did you or were you expected to give to the airplane manufacturers, to the designers? In the case of the DC-3, did you work at the level of --?

GILRUTH: Our product was a report called, "Requirements for Satisfactory Flying Qualities of Airplanes,"1 and that was a report that I wrote. It's a short report, but it has all the things that you need to have in an airplane to have good flying qualities, and it's quantitative, it's not just -- it should not be too flicky, too jerky or something, pilot's jargon -- it's something to measure, and put a number on, and so when you get through, you can have a seat on an airplane, and without knowing anything else about it, you can look at it and say, "That's a good airplane except for this and this."

DEVORKIN: I'd like to know a little about the dynamics of it. In no way then did you consider yourself a regulatory function?

GILRUTH: We were not a regulatory function. But they took those things that I wrote, and the Army Air Corps and the Navy used that, as far as their procurement goes.

DEVORKIN: Could you expand on that. As part of their procurement, in other words --

GILRUTH: In other words, they would tell their companies they wanted them to meet those specifications.


GILRUTH: For handling qualities.

DEVORKIN: Was there ever any political feedback, or, from the airline companies back to you, saying your standards or findings were not correct, or any problems like that, let's say with the DC-3? You said that your finding was not generally remembered or recalled.

GILRUTH: That's right. Well, a DC-3 was in service long before I wrote this report, "Requirements for Satisfactory Flying Qualities", so it was really, nobody would argue against this quick stall. It wasn't thought of as bad enough to ground the airplane for.

DEVORKIN: Did you ever have an instance in your first few years, when you did recommend the grounding of an airplane?

GILRUTH: No, I don't think we did. But when you design a new airplane, a new fighter, for example, you wanted to have stick force per g that was something between say 4 and 8, and you wanted to have a rate of roll that was, a helix angle that was greater than .07, and at high speed you wanted a rate of roll that would be, you know, something like 90 degrees a second am I right? I've forgotten now. But it's right fast.

DEVORKIN: Were these specifications that were given to you, to see if an airplane could meet performance standards?

GILRUTH: Well, you don't have a successful fighter unless it can meet these things. The interesting thing about it was that when I published that report, "Flying Qualities", we were in the war, and we always traded things with the British. Dr. Lewis, who was the head man in Washington, sent a copy of my report over to England, and we got a letter back, a whole bunch of stuff back from the British, saying they were very enamored with that report and thought it was a very good report. Furthermore, they wanted to send a mission of people over to talk to me, which really helped my career a great deal with the boss in Washington and with the people at the lab.

    And so they did send this mission over, and they had ideas. They didn't approve of all the ideas that I had, and we argued about things. Most of them, however, they did approve of. They liked that force per g -- they thought that it was very good.

DEVORKIN: So you set the standards?

GILRUTH: Yes, but I also said, force per g is the thing you should measure, and rate of roll -- it's obvious that rate of roll would be a key thing -- but force per g wasn't so obvious. But most of the things were just things that anybody would know you had to be able to do with an airplane, like you should be able to make a three point landing. In those days there weren't any tricycle gears, you realize, and you had to make a three point landing or you bounced. You had to have enough elevator control so you could get the tail down. Now, with the tricycle gear you want enough elevator control so you can get minimum speed in case you're in a small field.

    But it's just a set of requirements. I picked out what I thought were the critical things that an airplane had to do, and then people had to set what the numerical values were of those things. But you had to have the criteria set for what you were going to measure.

    The British were very much interested in this, and they had a few arguments, but we got together and we learned a lot from them, because they knew a lot more about fighters than we did. They had the Battle of Britain right on their doorstep, and they were talking with fighter pilots every day. We got to see a fighter pilot -- you know, in those days we were far removed from the war.

DEVORKIN: Can you remember the people who came over from Britain and what their particular positions were?

GILRUTH: Yes. One was Morien Morgan, who was the man working in flight research at the --

DEVORKIN: Farnborough?

GILRUTH: Yes, the aeronautical establishment, Farnborough, and Morien Morgan was running a flight test business sort of like I was at that time. The man that came with him was a fellow named Barrie Gates, who was a lovely man. He was much older than Morien, but he had a terrible stutter. He could not really talk, but he could write beautifully. He was a marvelous writer. And he'd get so frustrated when he'd try to say something, and he'd poke Morien and say. "You say it."

    I think those were the only two. There were a couple of others but I don't remember them. They were not the key people.

DEVORKIN: What year was this?

EZELL: '43.

DEVORKIN: You'd already been there at Langley then for five years at this time. This might be a good place to stop, and what we should do is pick up with how your responsibilities expanded after Soulé left, and the people you brought on staff and how you treated them.


DEVORKIN: When we finished the last tape, we said we'd ask you to go back to review how, after Soulé left, you developed your section on testing, who you hired, how many people came to work for you, how your group was structured, and get a sense of how the NACA (at least in your area), changed with the coming of World War II.

GILRUTH: Well, I inherited the flying quality research job from Hartley Soulé when he went on, I think he was put in charge of one of the wind tunnels, a new wind tunnel that had been built. My boss was still Floyd Thompson, and I worked directly for him, and by this time, I had begun to be sort of a leader of the flying quality work. I had two or three other young engineers working with me, and at the time, I wrote several reports with other people about analysis and prediction of longitudinal stability, about the lateral control required for satisfactory flying qualities, and so on.

    Another thing that sort of spun off of my work on stability was that I found that the knowledge that I'd learned about what made an airplane have the kind of stability it had, (such as the effect of the propeller on stability and so forth). I was able to predict the loads that airplanes experienced in abrupt maneuvers and pull-outs. Existing criteria at this time were more or less rules of thumb.

    For example, I found that the tail loads on a fighter airplane, the design tail loads, the most severe ones, were in the upload on the horizontal tail. The design criteria that were used by the Air Force, Navy and so on, actually said the worst load was a down load, and far less than it actually was. This, of course, was true on some of the other surfaces like ailerons, rudders, and fins. The critical thing on the vertical fin of the airplanes, believe it or not, was an abrupt aileron roll at high speed and high acceleration, and this was unknown. Strange as it seems, there was a rash at one time of airplanes shedding their vertical fins. Pilots loved to come back in after a mission and make a pull-up and a roll at the same time, which --

DEVORKIN: -- was this some kind of a victory --?

GILRUTH: A victory thing. And off would come the fin. It was unheard of, what in the world that could be, that wasn't supposed to be bad. But I calculated it out and I found it was one heck of a load on the vertical fin, so I wrote a bulletin for the designers of America, (it's listed there among some of my papers), and that was a very, very important piece of work.

    It wasn't hard for people to realize that if you're going to use ailerons at high speed, they had to be built strong enough to stand it. That was obvious. So the work that we were doing there at Langley Field had quite a lot of importance to American and British airplanes. We traded everything with the British.

DEVORKIN: You indicated that until you had contact with the British, you really didn't have very much feedback from fighter pilots in general.

GILRUTH: That's right.

DEVORKIN: Before the war, you had your own fliers, of course. To what degree did you interact with those fliers? How did they work with you as engineers? What contact did you have with commercial airline pilots or military pilots at all in the performance of aircraft? How significant was that in your concerns?

GILRUTH: Well, of course, starting out before the war, nobody thought very seriously about what it took to be a good fighter. You knew it had to be fast, fly high, things like that, but what made it? You knew it had to be maneuverable, but how do you define that?

    Of course the way you define it is, you have to be not only able to go to the extremes of the envelope of flight, but you have to be able to do it with precision. You have to be able to make that airplane go exactly the way you want it, point the way you want, which means you've got to have not only the ability to go to the boundaries of the envelope, but go there with precision. To do it just the way you want it, that means a very high degree of control, and in order to get that you have to have the right kind of force per g and the right kind of variation of parameters, which is what I tried to put into my requirements.

    It just turns out, in those days, that was all done without any boost systems. This was all done by balancing the control surfaces aerodynamically, or by using spring tabs or something like that. It's a whole new ball game now, because mostly it's power controls, and I frankly don't know how they do it now, but the airplane has to be the same. In order to be good, it has to have the same kind of responses to controls that it did naturally. The boost system has to be a faithful division of the load, so that the pilot still feels some variation with g and so on.

DEVORKIN: That's sort of what I'm driving at. Did you talk to pilots about the feel of the aircraft, and what were acceptable operating conditions for them?

GILRUTH: Well, that's true. That's the only way we were able to come to the conclusion that those were good requirements, by consensus of all the pilots that this was the right way. That's why it was so helpful to have the British come in, who had nothing to do with it, had just received my report, and said they wanted to come over and talk with us. That was a big help, because especially with the experience they'd had with the Battle of Britain, and with all the fighter pilots that they were able to talk with, they really knew a lot more about the actual war in the air than we did.

EZELL: Did you have any interaction with test pilots from Grumman?

GILRUTH: Oh yes, we knew all those people, and our own pilots used to do what they called sales work. Although they were civil service people, the head man, Dr. Lewis in Washington, allowed them to go and make proof test dives for the different companies for whatever price they could get, and of course, they made quite a lot of money doing that. But it also helped the NACA, because they would get to fly these new airplanes, and could come back and tell us about what they were like and what they would do. So we got a head start on the newest types that were coming out. So that was a good thing.

EZELL: Do you remember any particular pilots that were good at telling you what you needed to know?

GILRUTH: Well, Mel Gough was the best one that we had. Melvin was his first name. He later became chief test pilot, but in these early days Bill McEvoy was chief test pilot. He was a great pilot, but he could not really tell you what he meant. Gough, however, was very explicit and good, and Gough used to love to take me up and show me all these things. He was a teacher too, and he deserves a lot of credit from me for the amount of time he spent trying to show me all the things he learned about flying and so forth.

DEVORKIN: Did you like to go up with him?

GILRUTH: Sure. We even flew together one time in a single seater! I had one foot on the rudder pedal and one of his feet was on the other one.

EZELL: Not being a pilot, weren't you kind of scared sometimes, to go into some of the dives?

GILRUTH: Oh, we didn't do anything very outstanding in flying.

DEVORKIN: What was the procedure for a whole test sequence at the time, and did you design it? Did you take it over from Soulé? Did you modify the whole procedure, from the acquisition of the craft, to the testing and evaluation? Were there procedures written out? Were they formal in any way?

GILRUTH: No, we were always improving the instrumentation. We added more and more things. The thing I added was a yaw vane -- somehow other people knew angle of attack was important, but they didn't realize that the angle of yaw was very important, too. At first I just put a little mast up there with a vane on it and a sector on it, so you could read the yaw angle. " My gosh," the pilots would say, "this thing goes a long way sideways, doesn't it?" They had never realized that it was easy to get large side slip, frequently great enough to stall the vertical fin.

    Then we got to where we put a recording yaw vane on, and that was when we found out, with some of the transports, that you'd actually get over far enough to where you'd stall a vertical surface. On some big airplanes, when you stalled the vertical fin, you got a condition where the rudder would blow over, and if it was a big airplane it might be too heavy to push it back out and to recover.

    When we were testing a B-17, which had a very small fixed fin and big rudder, we found a rudder lock condition when the fin stalled. We called the Boeing Company. They were right in the throes of testing their new transport, and in the course of their tests, it experienced rudder lock and they couldn't recover and they crashed. In the investigation that followed, they found out about rudder lock. We told them about it. They also found out about it, and they put a big fin on that transport.

DEVORKIN: The 25 was a bomber, right? So it wasn't the 25?

GILRUTH: No, that was a North American, anyway. I'll think of it when I don't try.

DEVORKIN: You'll certainly have a chance when you see the transcript to work this over.

GILRUTH: They put a big dorsal fin on the B-17, at that time, and the yaw vane was very helpful -- while it doesn't show up in any of the requirements, it's very good to have a yaw vane on an airplane that you're trying to investigate, because it's a clue to why it behaves the way it does. Mostly they always put yaw vanes on them now when they do that kind of work.

DEVORKIN: As you took over from Soulé, you became in part an administrator as well as an engineer, and that put you in the position of having to respond, I would imagine, to various work orders. I'm interested in how you chose the problems that would be attacked, or whether they were assigned to you, and what the reporting procedure was for getting something into publication, such as a NACA report - how it actually got written, what the mechanics were.

GILRUTH: All right. The mechanics were very simple. You sat down and wrote it. I'll tell you, getting some of those engineers to write anything was difficult! It wasn't easy for me.    It was always hard to get a report written. People, especially engineers, don't write very easily.

DEVORKIN: Were you the one who cracked the whip or was it your boss Thompson?

GILRUTH: Nobody cracked the whip. If you didn't write it, your report was never published. Somebody else might write it. You might turn it over to somebody else. Because you had to write, you couldn't become a successful person at NACA if you didn't at least at one time in your career put out and publish, just like any scientist in any kind of a business. He's got to be known from his research work. And that was one nice thing about NACA, you had a chance to become known in the field, in the industry, by the work that you'd done. That's the way people did it, and frequently they would be in the NACA for a year or two or maybe five, and then they'd be out and get a job in industry and do quite well. A lot of our people did that.

DEVORKIN: My first question which was, how were your problems assigned? Did you decide which planes you would test? Did Thompson, did someone else?

GILRUTH: Well, Thompson had the say, but I always got to test the airplane that I wanted to test (of those that were going to be tested). Maybe he was just so clever that I always thought the way he did, without knowing it, but I don't think so. I think that we worked well together. I never had any arguments with him -- if he didn't like it, why, he was so clever that he could convince me that I really believed it, too. He was very bright and a very nice person to work with.

DEVORKIN: What about beyond Thompson--the actual liaison with those producers of aircraft?

GILRUTH: Well, we mostly tried to select airplanes so that we got various types which covered the gamut of airplanes. Occasionally, as I said in the case of this Lockheed, where the Air Safety Board asked us to take one and test it, that was a case where they wanted us just to fly it and see what we thought of it. But mostly we selected them ourselves. This is why we had good background for our research work.

EZELL: I noticed that many of the reports had more than one author.


EZELL: Was there usually one person that could sit down and write the results down better, and two or three collaborated on it?

GILRUTH: That's right. Mel Gough did a whole lot of the real hard work on these flights. He wasn't much of a writer, but he had a lot of ideas. He really had a stake in them, so his name is on a lot of the reports, although I don't think he spent a whole lot of time on it. He certainly spent a lot of time criticizing what we had written. That was perfectly all right. And there were others that you would bring in that had done a special lot of work or something on it; give them some credit. It was generally known in the NACA who really was the guy who wrote it. And you'd have an editorial committee. You'd have people from different places come, some from the wind tunnels and some from other places, and they'd all sit around, spend a day or two criticizing your paper, your results and so on. Finally, if everybody was satisfied or couldn't argue any more, you'd go ahead with it.

DEVORKIN: That was the next thing I was going to ask, about the internal review process. Who made up this editorial committee, what kinds of people were on it?

GILRUTH: Well, they were just other engineers from varied positions. Some from wind tunnels, some from flight. If there was a report on stability, you'd get the stability expert from the stability division.

DEVORKIN: Were these people who were working engineers or were they administrators?

GILRUTH: No, they were always people who were experts in the field. If it was on stability control, it would be somebody from stability control. We always had one guy who was mean intelligence. He wasn't supposed to know anything about that field, but he was there to make sure that if you tried you could figure it out.

EZELL: That wasn't your field.


DEVORKIN: Were you on this committee at one point?

GILRUTH: I was on a lot of those committees, yes.

DEVORKIN: So they were convened for each problem area?

GILRUTH: For each report there was another editorial committee.

DEVORKIN: Was there any administrative review after the editorial committee?

GILRUTH: Oh sure. And before as well as after. The report first had to go through the section head before it went anywhere, and he might kill it right there and say, "That's terrible, go back and redo it" or something, or maybe he thought it was good enough and he'd say, "All right, we'll take an editorial committee and we'll go right ahead."

    Afterwards, we had an English department that went over all the English in the reports. There were mostly all girls in there, and they would go over it and sometimes they made the English worse, but mostly they didn't. They were good, they all tried hard. Nice girls.

DEVORKIN: I'd like to know if there were any non-technical criteria for rejecting various reports, any political pressure that you feel was significant enough to warrant recollection at the time?

GILRUTH: No, I don't think we had any problems like that.

EZELL: Can you remember if your first report was 7\11\41 with White, "Analysis and Prediction of Longitudinal..."2

GILRUTH: I think that was probably my first NACA technical report, that was published for the great American public.

EZELL: I found a technical note that was 1940, with Thompson, that's on Tech Note "Notes on the Stalling of Vertical Tail Surfaces and on Fin Design".

GILRUTH: That was a note because we wanted to get it out fast. It was important.

EZELL: That wasn't scrutinized like the reports.

GILRUTH: Well, it was read a lot, but it wasn't something that was bound in the big book that was saved each year.

DEVORKIN: Before the war, what kind of a budget did you have? Did you have enough money to do what you wanted to do?

GILRUTH: I'll tell you, when I came to NACA, the annual budget was 1.35 million dollars.

DEVORKIN: For all of NACA?

GILRUTH: For all of NACA. Including the Washington office. There were something like 150 engineers and scientists on that staff. The overall employment was something like 400. You know, every kind of help, mechanics, people in the shops, so on and so forth, and computers -- in those days computers were girls, they pushed Merchants.

DEVORKIN: Were they all Merchants, by the way?

GILRUTH: I don't know.

DEVORKIN: But that's the name you remember.

GILRUTH: That's right. The computers were all girls, and some of them were very bright, too. They knew a lot of mathematics. We had math graduates come in as computers. They were very good in math, and they'd help the engineers and scientists with their mathematics, if they had a mathematical problem.

DEVORKIN: Did they help organize the computing staff to solve these equations? In other words, would the engineers give the supervisors of the computers the equations?

GILRUTH: Sometimes they would. I never had that kind of problem myself, but some of them who had special things, had that kind of help from the computers.

DEVORKIN: What kind of service help did you actually require in your area? What kind of budgetary needs did you have other than manpower?

GILRUTH: Well, we needed instruments, that kind of equipment.

DEVORKIN: Did you have enough money for these things that you needed?

GILRUTH: Sure. We never had enough money for all the things, but we had enough, it seemed like we did. We never ran out of work.

DEVORKIN: No, but I was wondering if your budget for test equipment and for flights, all this costs money, was comparable to what was available to engineers in commercial industry, or whether you felt you were on the cutting edge?

GILRUTH: I felt that we had a good balance of money to spend for what we were trying to do. We were pretty well off.

DEVORKIN: -- so even before the war --

GILRUTH: -- we were very frugal--we certainly were. We didn't get any more money than we needed.

DEVORKIN: How did conditions change with the coming of the war?

GILRUTH: Well, we started out, some of us got drafted.

DEVORKIN: You weren't in excepted service in the NACA?

GILRUTH: We were -- but in the beginning, we weren't, and we lost two or three of our guys temporarily, and they worked out a deal where we actually enlisted, we were part of the enlisted reserve, and then we were sent back to work for NACA on inactive duty, which was fine.

DEVORKIN: Were you one of them?

GILRUTH: Yes. We all went and got inducted, and they turned usback.

DEVORKIN: What was your rank?

GILRUTH: Private. The lowest there is.

DEVORKIN: But you were a supervisor by that time, certainly?

GILRUTH: I had my old title, I didn't have a suit, I was a civilian for all practical purposes. I just was a member of the enlisted reserve, unassigned, or something like that. It was a special deal that Dr. Victory or the Secretary in Washington worked out with the armed services, which was really quite clever. It didn't take a lot of money and a lot of fuss to do, and the Army and Navy didn't want to kill the NACA, they needed them.

DEVORKIN: Exactly. What was your own personal contact with the NDRC or OSRD?

GILRUTH: Well, not very much, until later on in the war, and they weren't so big in aviation, in the kinds of things that NACA did. The NACA did a lot of things for the war airplanes. For example, the full scale tunnel cleaned up nearly every airplane except the bombers. The bombers were too big to go in the tunnel, but all fighters, all the torpedo planes and all those went in that tunnel for cleanup, drag cleanup. They'd put the airplane in the tunnel, and they'd run the tunnel. You could run the engines on the airplanes. Then we'd measure what the drag was, and then you'd go ahead and try different kinds of fairings and different things. The engineers got pretty good at this. They'd look at it and say, "That's lousy, certainly we can do this." They'd fair these places, and then, by the time they got through, they'd reduce the drag of that airplane a great deal. Boy, they had the people from the companies right there, so they'd be designing how they're going to change those fairings on the airplane.

    That was a very, very popular program, because it was such a neat way of making airplanes a lot faster, and everybody knows that it was a very good way of short-cutting all the testing you had to do otherwise.

DEVORKIN: Did the scale of your own flight research section change with the war? Did you get more men, more assignments?

GILRUTH: Yes. We got more men, more assignments-- we grew. I can't give you any figures on it.

DEVORKIN: Just order of magnitude scale would be fine.

GILRUTH: Well, we had started out in a little lean-to next to the hangar, there on the side of Langley Field. By the end of the war we had a great big building, with two floors and a whole hangar alongside of it, for the same things that we were doing before, only we had that many more people and that much more equipment. I guess we probably tripled or something like that.

The rest of the field did, too. I know their budget went up a great deal. There was inflation too, but mostly it was expansion.

DEVORKIN: As you set the different types of parameters for what a fighter aircraft should do, did you have feedback, meetings with military planners, with people who were familiar with tactical fighters?

GILRUTH: Yes. Yes, we had a good relationship with the people at Wright Field who did all the procurement, and there were some civilians there. Cortland Perkins -- I don't know whether you knew Cortland Perkins or not -- he became president of the Academy of Engineering for the last ten or fifteen years. He's retired now. But he was a civilian over there when I was a civilian at Langley, and we had a very close relationship. Whenever they'd get a new airplane, he would get me out there, and sometimes I'd take Mel Gough, our test pilot, and he'd fly the airplane. We'd get a little head start, if there was something wrong with the airplane that needed to be done, Perkins would start the paperwork for the request to come from them, Air Material Command, for NACA to do something on this airplane. So we had a good relationship. I think we made the system work very well.

DEVORKIN: Were there any shortcuts you had to take for war pressure? Did review boards meet more frequently or were they dispensed with at any level during the war, when development was greatest?

GILRUTH: We didn't have any meetings unless we really had to have them. We used to have joint meetings. For example, during the war, the P-47 which was one of our best fighters developed a problem called stick freezing in high speed dives. P-47 pilots would report that they got in a dive and they actually could not pull out. They kept pulling and pulling on the stick until they were getting dangerously close to the ground and then all of a sudden the airplane would respond and pull out just before hitting the ground. Some of them lost ailerons when they overshot the limits and others bent their wings. That was a big mystery, why in the world was this stick apparently freezing? There were lots of airplanes lost, and when I get talking to some of the old pilots about that they still say, "Boy, that was something."

    Well, Perkins called a meeting at Wright Field and we got all the experts to come to this meeting. We had our toptheoretical    man from NACA, Dr. Therdorsen, and we had the head of the load section, Mr. Richard Rhode, and we had other experts. Each one had a different idea of what it might be.

    Some believed it was drastic deformation of the elevator surfaces, others thought it was aerodynamic problem at the tail surface, and not one had the correct answer to the problem. Actually, one of the experts actually said, that the stick was not responding because the elevators were freezing due to condensation in the hinges and elevator gap!

    So, we decided that we really needed to have a test, and we would put some recording instruments on the airplane and see what it really was. We were going to hire a test pilot, pay him a lot of money to make these dives, but Perkins found a young major at Wright Field, who said, "I'll be glad to dive that thing."

DEVORKIN: You mean, actually put the plane into a stick freeze condition?

GILRUTH: Yes, put it into a dive, and it would freeze and then pull it out. Well, this young man was also the Olympic champion weight lifter, so we figured he could pull it out.

DEVORKIN: He could pull the stick loose, if anybody could.

GILRUTH: Yes. This was a fellow named Perry Ritchie. His idea of heaven, he told me before this, was a throttle in one hand and a hamburger in the other. He was a happy-go-lucky guy. We put recording instruments in the P-47 and he took it on up to 30,000 feet, which is about as high as it would go, put it straight down in a dive -- and pretty soon, we saw him coming back in and the plane was okay. He said, "Boy, that was a good one, it really does freeze, all right, but I was able to pull it out."

    We looked at the records, and sure enough, when that airplane got up to a Mach number of about .86 the response to the elevator was greatly reduced. The P-47 had 230-15 airfoil -- that has thickness up forward and it is over 15 percent thick. In other words, its depth is 15 percent of its length, which makes it pretty fat, and that's one of the things we learned, that you didn't use fat airfoils when you got near the speed of sound. In any case, it did seem to freeze. You could move the stick, though. It didn't freeze, it's just when you moved it, the amount that would normally bring it out of a dive, with the flow breakdown on the wing, you had destroyed the response of the airplane. You could move the elevator but it wouldn't cause much of a change in lift response, so that you were actually moving the elevator but at those speeds normally you don't move it much anyway, so you were moving it as much as you ever could, but it wasn't doing anything. So that's pretty much what Perkins and I thought was the trouble, the breakdown of flow on the wing.

DEVORKIN: Is this turbulence caused by the bow shock when you're close to the speed of sound?

GILRUTH: No, there isn't a bow shock yet because you're not that close to the speed of sound, which would give a shock, a normal shock wave off the top and off the bottom, that move back together. Then when you get to a certain place, you get separation of flow, because the flow can't converge, you can't get the pressure recovery, so it just separates. When that separates, you lose your lift. You lose your downwash. So you've got a very, very stable airplane. It's so stable that you can move the stick and nothing happens. Fortunately, when you get to lower and lower altitude, the drag goes up to the place where it forces your speed down below where that sharp separation takes place, and the flow reseats itself and then it's a regular airplane. But you're apt to pull the wings off because by that time you're just scared to death, afraid you're going to hit the ground.    Perry Ritchie didn't do that. He did it just right.

EZELL: Can conditions like that be simulated in a wind tunnel?

GILRUTH: Well, you could have, if you had a wind tunnel then that you could go that fast with. You could now, but even now, that side of the speed of sound is hard to do, because it's getting close to the speed of sound, and you have to have a very small model in a tunnel in order not to choke it.

EZELL: So there's still no substitution for those kinds of dives and things test pilots do.

GILRUTH: Well, we don't have a problem anymore because we know enough to design without it, and you wouldn't have that kind of a problem.

DEVORKIN: This time, though, you knew that you were pushing closer and closer to the speed of sound and that somehow this was a manifestation of that barrier.

GILRUTH: That's right, because we actually photographed shock waves on the wings of the Mustang. You get the light just right, with the sunlight shining on a wing, you can see it (even on transports today) if you're careful and look at the right time.

DEVORKIN: So these are airborne aerial cameras on the fuselage or on the wings that were able to photograph the wave.

GILRUTH: Some test pilots would just take a camera along and take pictures. But you didn't do this with a P-47, not when it was in this dive! Nobody would take any pictures of that.

DEVORKIN: What kinds of sensors did you have on the wings that allowed you to realize that there was not any lift?

GILRUTH: We didn't. We presumed that since you moved the elevator that much, and the elevator certainly was still working, that it had to be very stable. And there was a lot of buffeting in that airplane, so you knew that there was broken down flow.


DEVORKIN: You said that was an interesting one. Was that one of the more memorable situations with the P-47 you were involved in?

GILRUTH: Yes. That was an interesting one.

DEVORKIN: Did that get you more involved, more interested in better understanding the sound barrier? Was that an ultimate goal?

GILRUTH: No, we were a long way from the sound barrier in that airplane. It wasn't too long after that, though, that we were involved in designing an airplane to go through the sound barrier. By this time, I had changed, I'd done a lot of different things. I'd invented a technique called wing flow, which allowed one to go through the speed of sound with small models and find out good and bad air foils, and I'd also been pulled out of flight research and put in charge of Wallops Island flying, which became a free flight range for aerodynamic research.

DEVORKIN: This is during the war or after?

GILRUTH: This was in early '45, it was May of '45, just after the war.

DEVORKIN: What about this wing flow technique? How did you come to it? Was this a wind tunnel --

GILRUTH: Yes, this was like making a wind tunnel along the top of a wing of an airplane. A Mustang had a thinner wing than the P-47, and we'd made some surveys of the pressure distribution on the top of the wing.

    I had noticed that the flow went quite smoothly up to and through the speed of sound, over a region of about a foot or so above the wing of this airplane. When you gradually increased the speed of the airplane in a dive, that flow went gradually up and up and up in speed, and then, when you slowed down of course it slowed down. The flow covered a Mach No. range from about 0.8 to 1.25. I thought, why couldn't we put a semi-wing on there on a little balance that would be down inside the wing of the airplane and measure the lift and drag?

    So we did that. The first wing section I put in was the one used by the P-47 airplane, which I knew went bad. It showed, by the time it got to a Mach No. of .86 the flow had broken down and the lift curve slope went to zero near the speed of sound.

    But if you took a wing that was 8 or 9 percent thick instead of 15 percent thick, and tested it the same way, it held its lift. It kept its lift right through the speed of sound. The drag went up, but it didn't go up nearly as much as it did on this P-47. So, it looked like you could go through the speed of sound, if you had a thin wing at least 8 or 9 percent thick.

DEVORKIN: At least or not more than?

GILRUTH: At least that thin. I was having a ball with this technique, because nobody had a wind tunnel that would test through the speed of sound. Free flight was very slow in getting anything, and here I could find out what happened in this important speed range.

    The people in industry really were pleased to have something to go on, and my boss in Washington, Dr. Lewis, was very pleased.

    The only thing that was awkward about it was, he thought it was so important that he made it top secret.

DEVORKIN: It didn't appear in a tech note, I guess.

GILRUTH: No, it didn't and I of course couldn't talk about it.

I had this data, but I would tell people they ought to put something thin on it, to make the wing thinner. Somebody would say, "Why do you say that, how can you know that?" I'd say, "I can't tell you."

DEVORKIN: Then we couldn't retrieve when you did this from any kind of technical report. Can you tell us how when and how you came up with that idea?

GILRUTH: It was I'd say 1944, about July about the middle of '44 I was working on that. I was also working with John Bailey also of NACA on this free fall heavy bodies to measure what happens to the drag of bodies going through the speed of sound.     That was really the first free flight experiment through the speed of sound that we had. We took these streamlined bodies up to 40,000 feet in B-29s. The drop bodies had telemeters in them to measure the pressure distributions round them and an accelerometer to measure the drag. We used a radar to measure the speed. We dropped those things over Wallops Island on the Eastern Shore, traced them and recorded the telemetry, and we got some of the very first data on things going through the speed of sound.

    The tail surface of the falling bodies also had an airfoil tail section, and so we measured its drag with one channel of telemeter. Now these data were simon pure. There was no question that this was a true drag. With my wind flow, I had argued that I knew it was right because I thought things worked that way, but the falling body data was simon pure. So we had one or two things that we could compare our other things with.

DEVORKIN: I have two questions. First your interest in passing through the speed of sound, was that only for manned craft flight or were you beginning to be interested in the design and behavior of missiles?

GILRUTH: I was always more a manned flight person myself, although in 1945, I was pulled away from my beloved wing flow, and put in charge of creating and running a guided missile research station over on Wallops Island. The NACA fathers together with the Army and Navy people on the NACA committee, decided that NACA ought to get into that business. They didn't know what they were going to do, though because when I inherited it, I found that I was supposed to run a guided missile station, and I knew that the Air Corps (at that time) and the Navy both had their own places. They had Inyokern, for example, a Bureau of Ordnance, and the Bureau of Aeronautics was taking over Banana River. I think that it was the Air Force that later took that over from the Navy, and so it was obvious to me that the outlook for NACA was not going to be good. So we devised ways of making and measuring lift, drag, control, effectiveness and all the things that you did in wind tunnels, but do it in free flight. So data through and near the speed of sound.

DEVORKIN: I'm interested in free flight technique and the criticism of the wind tunnel people, and I'm wondering what your relationship was with people like John Stack?

GILRUTH: John Stack and I were always good friends. He was one of the wind tunnel people --

DEVORKIN: I know he had hopes for supersonic wind tunnels and something --

GILRUTH: Oh yes, he was the guy who invented the slotted throat tunnel finally, that allowed us to go through the speed of sound with a wind tunnel.

DEVORKIN: But did the wind tunnel people criticize your free flow technique on the basis that it was not controlled environment, that it was on a wing that had a barrier on one end and was free on the other? What kinds of arguments and criticisms did they have?

GILRUTH: Their greatest argument was one that the Reynolds number was so small.

DEVORKIN: Oh, because of the size of the thing. I see.

GILRUTH: But actually when, you got right down to it and you analyzed the model, the results I got from the wing flow, full size results, they were very close. But you couldn't, if you didn't know that it worked, it could always be shot done by someone who would say, "The scale is too small."

    But in any case, it did help the industry quite a lot in the days when they didn't have anything better. We soon began to get enough stuff out of Wallops Island on controls and on drag so that people could do a pretty good job of designing. It still wasn't like a wind tunnel, though, where you could put the model in and measure it, do all these things like we could in a regular wind tunnel.

DEVORKIN: How long did that technique remain classified?

GILRUTH: It didn't last more than six months. Dr. Lewis -- that was something that he didn't want the enemy to get hold of, so he kept it a lot longer that he needed to.

DEVORKIN: I don't want to leave the war years without asking you, did you do any proof testing in the European or Pacific Theaters? Did you actually have any experience under combat conditions? Or did you brief pilots or debrief pilots who'd come back who had done any actual fighting?

GILRUTH: No. The closest thing we came to that was when Morien Morgan and S.B. Gates came over from England, and they told us about interviews with the RAF pilots.

EZELL: In '46 you did a report called "Appraisal of German Research During the War"3 relative to that of the NACA.


EZELL: Yes. I'm assuming that was done from looking at written reports?

GILRUTH: I don't remember.

EZELL: I'll copy it and bring it next time.


DEVORKIN: It would be interesting to know if you did ever test captured German hardware or material?

GILRUTH: We had a Jap Zero which we tested. But I don't think we had any German airplanes.

COLLINS: One of the things the Allies were very interested in after the war was German developments in wind tunnel technology. Was that something that may have fed back into the NACA?

GILRUTH: Yes, we had John Stack over there after the war who was top wind tunnel man, but they didn't had a slotted throat tunnel. They had the same kinds of problems with compressibility that we did.

DEVORKIN: Let's move on then to the missile research. You said the NACA wanted to get into it, even though others were already in it.


DEVORKIN: I'm wondering who it was in the NACA who pushed for that?

GILRUTH: I know one of them very well. His name was Gus Crowley. He became deputy director for Dr. Lewis and retired before we lost any astronauts but we already had the project Mercury going on at the time he retired.

DEVORKIN: Crowley is a name I've heard before, along with Walter Diehl.

GILRUTH: Walter Diehl was a Navy officer, captain in the Navy, who wrote books on airplane design, and also represented the Navy in that department of design. He was a nice man, but by not wanting to ever give up his engineering, he forfeited his chance to be an admiral.

DEVORKIN: That's interesting. But I'm interested in what contact you might have had when you were literally assigned this task of taking over the Wallops testing and getting into missile work, whether you or members of your staff reviewed captured German documents that related to missile research, because there was a tremendous amount of material that did come over.

GILRUTH: A great deal of that material -- I was the first employee of this place, Wallops Island, and they had already bought the land. They had decided that we need at least 100 miles out in the ocean to fire. And actually, the situation was such, we had the area between Wallops Island and Spain we could have used. There wasn't that much out there. But we didn't know what we were going to do.

    One of the first things that we did over there, I insisted that I wanted to get over there before we built any permanent facilities, because I wanted to know what their problems were and what we were trying to do before we built the facilities. So often you see the government go in and build everything and then find out, that isn't what we're going to do at all.

    So I insisted on getting over there and trying to fly something. The Air Force had a missile called Tiamat -- it was supposed to be an air-to-air missile. We made some models of it and we thought we would try it and see what we could learn by free flight. We made it geometrically the same, put all the auto-pilots in it and a sustaining rocket to make it fly. It was a subsonic missile. We went through the whole nine yards, including putting in a launch site that was temporary, of course. We did cast a big concrete slab so we could work it and keep out of the sand, and we had these buildings that you could pick up and set down any place, I forget what you call them -- Butler buildings or something. We put quonset huts over there, and we had a cook and we had some guys that we would go across there in a little boat, across the marsh, and then we'd get out there with the mosquitoes and we'd try to work. We actually flew a Tiamat and got it to go flying around, and after we got it done, we said, that's all right, but what did we really do? We wouldn't be doing something like that. We aren't going to add anything to the knowledge by what we did. We just showed that we could get out and do it under adverse conditions.

    So before we really got started, it was obvious that the NACA fathers and their advisors who said, "let's build this thing for a guided missile range" were really not hip. There wasn't a need for that; the defense services had their own ranges, and they were going to have to use them to test their own missiles, and that was obvious to everybody. They wouldn't want to give us those to do testing on, because they'd just built multi- million dollar sites to do it with.

    So what would we do? Well, I came up with the idea that we'd have systematic models. I could get solid rockets from the Navy for nothing -- that is, these solid rockets that you go poom, poom, poom with. They are good enough to drive something up to Mach 2 at low altitude. So we got cheap bodies that we could make and we fastened wings on them, varying the sweep, the thickness, and so on, in systematic ways. We were able to do things more cheaply than the winds tunnels, and we were going right through the speed of sound. We had high Reynolds numbers. We had all this stuff.

DEVORKIN: What were your recorders? You had accelerometers?

GILRUTH: For drag, we could do it just with a doppler radar. It was accurate enough, you could measure the speed accurately enough. You could just differentiate that curve and get drag. Dr. Lewis came over, he was an old man then and he had a bad heart and he was worried sick about Wallops Island, because he knew as well as I did it was a wild goose chase. So he came down, and he saw this systematic -- I had a chart that showed all these things it did. He looked at that. I fired a rocket and it came apart. Dr. Hunsaker, who was the head of NACA at that time, says, "So your technique is no good, huh?" Something like that. And I said, "Yes the model did break, but we know how to make the wing stronger. We'll fix it and will stay together." Dr. Lewis, the last time I saw him, just before he got on the airplane he said, "But, I've been worrying about Wallops Island, just worrying sick about it, but I feel good about it now. I think you've got the answers to what we can really do, and do something for the country."

    And we did it. After the first year, the High Speed Subcommittee -- you know, we had the subcommittee system -- got together, and they said, "Expand the Wallop Island money by 300 percent because we want more of that kind of work." And by gum, Congress did it. We got our funds increased. We did that kind of work as long as -- well, it was only about five years, I think, I was involved in that thing, and then it got into higher and higher speeds and so on and so forth, but they were things that you couldn't do any other way.

EZELL: Who do you take with you to Wallops?

GILRUTH: Well, a lot of guys who were just coming out of the war, I was able to pick up. That's where I got Max Faget and a lot of the guys that had been mainstays of the space program.

EZELL: Did Cadwell come along?

GILRUTH: Cadwell -- Cadwell designed our models that we used on Wallops Island, and he put together a bunch of model makers. He was one of the leaders. He had a boss at that time. We build up cadre of people that knew how to make models, build them so they could be made easily, strong and cheap. That was a whole different kind of operation than NACA had ever done before, or anybody else.

DEVORKIN: How was it different?

GILRUTH: Well, we were flying precision models as cheap as you could build them, with instrumentation that was not buried in the models but was external. Occasionally we'd put a spin in them or a telemeter. We also measured aileron effectiveness just by using a spin sonde which was a simple transducer that would just send a radio signal that was polarized, and we just measured that, and that would give you the rate of roll.

DEVORKIN: There were a number of aspect sensors and spin sonde designs right after the war.

GILRUTH: We were able to get a lot of things that were excess.

DEVORKIN: What contact did you have with people in the Bumblebee program for APL, or some of these things?

GILRUTH: Well, they didn't have the same kind of thing at all. They were trying to do something entirely different. They were trying to do something much more difficult.

DEVORKIN: They were trying to develop an actual missile.

GILRUTH: They were trying to do that, yes.

DEVORKIN: You were taking already developed missiles and making models of them and testing.

GILRUTH: No, the models we made were designed to find out how ailerons worked through the speed of sound, what the drag of wings were, what the drag of bodies were, what problems you had with controls going through the speed of sound. Some of the models got quite difficult, because if you wanted to see how an airplane behaved, the whole thing, you'd have to have an airplane shape going through the speed of sound, and that took all kinds of instruments in it. We didn't do many of those because they were expensive.

DEVORKIN: You'd take the elements of the ailerons.

GILRUTH: We took the elements and tried to do them. We tried to be clever. And we were able to do a lot of systematic work that made the picture quite good, because if we could measure it, what was happening was true. We knew that. It was free flight and a high Reynolds number and it was everything it was supposed to be.

COLLINS: In a way it sounds like the title of the Guided Missile Research Group was kind of misleading

GILRUTH: Oh yes. We called it PARD finally, Pilotless Aircraft Research Division. PARAD meant an aerodynamic outfit that was finding out what happened to wings, bodies, controls through the speed of sound, and higher Mach numbers, too.

DEVORKIN: At what point did you get totally taken over to this new work, and cease to miss your war work and pre-war work?

GILRUTH: Well, Dr. Lewis was nice about that. He said, "Bob you ought to travel. I want you to go to Europe and give a paper." Well, I had never published that work on the little models above the wing, so when I went to England, I give a paper on that, and had a lot of fun. It was new to them. They were still back well behind us on the speed of sound. They were all interested in it.

EZELL: That was the paper to the Royal Aeronautical Society.

GILRUTH: Yes, that's right. So that was the end of that. I gave that paper and I was lost to other things.

EZELL: That was 1947.

DEVORKIN: Going back to the committee, Hunsaker's efforts to have the NACA move into this new field of missile and rocket research, which, now it's rolling, in his book on page 383, identifies, starting really in '44. You've already expressed your feelings about how this was a duplicate effort for the military services, but I was wondering whether you were involved in the special committee that was appointed that had Hugh Dryden as chair in '45 to look into how the NACA was going to get into it, and what input you had.

DEVORKIN: That was the first committee that was convened by the NACA then?

EZELL: First meeting of that committee, 1958.

DEVORKIN: Oh, in '58? I was thinking of the one in '45.


DEVORKIN: We might look at page 383.

GILRUTH: This is the thing, this is just before NASA was formed, yes. Okay '45?

EZELL: Have you got that on your schedule?

GILRUTH: I don't doubt that there was a committee or something formed --

DEVORKIN: This is a Hunsaker NACA Memorandum, Guided Missiles, NACA Program and Facilities, Notes on Discussion at meeting at NACA, December 18, 1944, when Hunsaker appointed the Special Committee in January; he listed its functions, and there are seven functions. "To review NACA research results and to control their issue, its reports," and that is Hunsaker to members of Special Committee on Self-Propelled Guided Missiles, 25 January, 1945. And it was that Committee on Guided Missiles that was created by the Joint Committee on New Weapons and Equipment of the Joint Chiefs of Staff.

GILRUTH: I was on that committee. But that was not a NACA committee.

DEVORKIN: Okay, but you were on it as a representative of the NACA because of your Wallops Island work?

GILRUTH: No, I wasn't but I was on it, I think I was on a committee. Dryden was not -- Dryden was close to NACA for many years when he was at Bureau of Standards, and it wasn't until '58 or so that he was really at the heart of NACA, although he was -- I remember him, almost always, as being close to NACA.

DEVORKIN: I know that he was certainly close to missile research, because he was chairman of the visiting committee for APL.

GILRUTH: Yes, and he also had his own missiles, you know, that he designed. I can't think of the name of it now. In any case the war ended before it was ready for use.

DEVORKIN: I don't know that either. It would be interesting to know more about that.

COLLINS: But in any event, in structuring NACA work on guided missiles, you didn't really receive any specific consultation from the military? There wasn't any input about what they would like?

GILRUTH: Well, I can't say there wasn't any input. We talked to a lot of people, about things, but I can't tell you anything very specific right now. We talked to military people all the time, in our business.

DEVORKIN: Yes, quite right. You mentioned that you changed the name of this division several times, or at least once. In '46 it was called the Auxiliary Flight Research Division, it became the Pilotless Aircraft Research Division. That reflected your change of goals, to achieve a rational goal for Wallops Island.

GILRUTH: I think so, yes.

DEVORKIN: That would be the best way to describe it.

GILRUTH: Yes, that was a good name. Everybody likes a PARD.

DEVORKIN: You continued in this until 1951, for a total of four or five years.

GILRUTH: I think that's right.

EZELL: Did you talk at all about the work you did in the Ram jet in connection with Lewis?

GILRUTH: Well, we were both working on the Ram jets. In PARD, Max Faget and Paul Hill created a Ram jet that flew up over a Mach number of 3, which was a world's record in those days. But none of the military really wanted a Ram jet by that time.

DEVORKIN: But wouldn't they learn by your example?

GILRUTH: Sure. Lewis had their own Ram jet program, and they just dropped theirs from an airplane, and they'd do it over Wallops Island and then we'd track it. Ram jets turned out to be dogs. Nobody really wanted a Ram jet after they found out how hard it was -- they can't take off and fly -- you've got to take it up to speed, and then turn it loose, and it's not an easy thing to do at best.

EZELL: Did the military suggest that NACA do some testing and work?

GILRUTH: Oh, they were always for us doing all the things we could possibly do.

DEVORKIN: Did you feel as if you were a free agent in the NACA, to engage in basic research problems, or that you served a testing service function.

GILRUTH: Well, you had to do some of both. If there was some very important project the military had, and you could help, you felt you had to do it. If you didn't ruin everything else you were doing. You had to weigh everything. But you wanted to help the military because they're your military as much you anybody else. So NACA always had an open mind to try to do the best they could do with what they had.

DEVORKIN: Was this really your attitude?

GILRUTH: Yes. Remember the Ram jet Project, the Boeing Co. had a huge project, spent millions and millions of dollars on it. It was an antiaircraft Ram jet, and of course for a Ram jet to be an antiaircraft, that meant you had to bring it up to speed with a rocket and then start the Ram jet, and it had to do all the maneuvering to catch the enemy bomber or whatever the enemy sent over.

    It seemed to me, I can't remember the name of it, but that was a best seller. I mean, that took an awful lot of money over years of time. Everybody would know that one, if I could think of its name.

    All of a sudden people realized the Ram jet was taking everybody for a ride. And it was not the right kind of ride. There were no successful Ram jets. We could get them to fly but they never were useful.

DEVORKIN: Was this an issue when you were chief of the Pilotless Aircraft Division, or later on?

GILRUTH: We had built some Ram jets because that was the thing to do, and we did well. We built some good ones.

    But after we'd done it, nobody was interested in it. We built one that went to a Mach number over 3, very high altitude, and nobody in the Air Corps or Army or Navy was interested, and Hugh Dryden, who had a lot of drag with all of those people, a lot of in with them, he said, "Well, I've called everybody I know but nobody wants it. Nobody wants to follow up on it." That was enough for me. I didn't spend any more time on Ram jets.

EZELL: This was '49 '50.

GILRUTH: I remember Hugh saying, "Nobody seems to --I've taken it all around." He felt it was a very advanced piece of work and he was really pleased, but nobody wanted it.

DEVORKIN: Someone asked you to do it in the first place?

GILRUTH: No, we did it on our own. Max Faget and Paul Hill had an idea of how to do it, and they had a good idea because it sure worked. It used ethylene for fuel, and it was relatively simple.

DEVORKIN: When it was not accepted by the services or by any possible commercial users, how did that affect your division, your work?

GILRUTH: Well, we just didn't work on Ram jets any more. Most of those people were made available to do something else.

DEVORKIN: What were those other projects?

GILRUTH: Max and Paul Hill were so good at anything, there was no problem. I believe they both became interested in re-entry bodies.

DEVORKIN: Let's go back and spend some time talking a little more generally, before we go too far into your next role as assistant chief of research. As we said at lunch, Hampton and the whole environment around Langley changed a lot, has changed a lot.


DEVORKIN: What was it like when you got out there? What was the atmosphere for living? Did it continue to be outpost duty, or was it very pleasant? What is your sense of it?

GILRUTH: Well, I left Minnesota when it was 20 below zero and two feet of snow, and I arrived in Hampton the next day, and it, oh, about 45 and overcast. The grass was green and the magnolias -- leaves were on the trees. I got out in that air, and it was so balmy at 45, my goodness! I looked around, said, "gee, this is really neat," and I had to go and ask the man at the station which way the town was, and he told me, "walk up that street." I said, "Which is the best hotel?' He said, "There is only one." I walked up with my one bag. I had my things, and went to this hotel, and called up an old friend of mine, Lo Ridert, and we got together, and he took me out to where he was living there at Rosalyn Manor, which was a marvelous old castle of a place, that was a very wealthy person's residence before he died. They had a boys' club there, a lot of the bachelors had gotten together and rented this whole place and had a housekeeper that kept it and cooked for them. They were living like kings over there. Unfortunately the place was full, or I'd have been over there, too.

DEVORKIN: That's too bad.

EZELL: Were you married yet?

GILRUTH: No, I wasn't, but I was about to be married as soon as I got well settled. It wasn't a tough place to live. I thought it was fine. A lot of people thought it was very primitive though. There were lots of people that didn't like living in Hampton, because they were used to bigger cities and things like that. I'd lived in Minneapolis for long enough so I didn't care about the big cities any more.

DEVORKIN: So your entire life, at least in the beginning, revolved around the job? Is that a good description?

GILRUTH: No, that's not, because I really started building a boat almost right away. I had to have some project of which I had sole control.

DEVORKIN: Maybe you should tell us a little about that.

GILRUTH: Well, I wanted to build a sailboat. As I was building this sailboat, I started to read up about drag of boats. I found that the speed at which you could go in a boat wa proportional to the square root of the length, so the bigger the boat was, the faster it could go, until it hits speed which is dependent on its length.

    So I though, my goodness, I've got to do something about this boat. I don't want to stop at 6 knots or whatever the speed was of this particular length I had. I'll have to get it out of the water. So that's when I decided I was going to work with hydrofoils.

    This boat, I said, will have two hulls. So. I built hulls in the living room of an apartment. Fortunately my wife was just as interested in crazy boats as I was. She was a pilot, a 99er, and knew all kinds of girls that flew airplanes. Anyway, she helped me with this boat, but we didn't finish it. The war came an got us before we did anything with it.

DEVORKIN: By that you mean the pace of work increased.

GILRUTH: Yes, the pace of work increased, and we did get to work on it some, but we did move from this apartment to Buckaroe Beach, which was much better place to work on a boat. Buckaroe Beach is a place in Hampton near the Chesapeake.


DEVORKIN: The criticism has just been leveled that you skip around a lot. You jumped several years, because I understand that sometime in the mid-forties the boat was finished.

GILRUTH: You're right. We did finish it, and I can't remember when we first sailed that boat.

DEVORKIN: This was the same boat you'd started?

GILRUTH: Oh yes.

DEVORKIN: The hydrofoil.

GILRUTH: The bath tub models were made in 1938. That was just about a year after I had married. In 1941, we decided to make it a hydrofoil sail boat, and made our first successful run under sail on the Chesapeake Bay in 1941. Then we took it apart and put it back up in the garage afterwards and didn't sail it again, and it was later turned over to Vannevar Bush. He got a very important idea, that he thought the hydrofoils were going to be so effective in all kinds of shipping. He formed a company and he said if I'd patent my original sail hydrofoil, those plans would be worth a great deal, and he'd give me a generous amount of stock in his company.

DEVORKIN: This was after the war?


DEVORKIN: Did anything come of that?


EZELL: Worthless.

GILRUTH: That's right.

DEVORKIN: When did you first meet Vannevar Bush?

GILRUTH: Well, it was in this. He really was excited and he'd been wondering how he was going to get patent coverage on the hydrofoil. Here was something ideal, I could patent my sailboat. The problem he (Bush) had, he had a fellow named Shearer, I think his name was Shearer, and he did most of the calculations for Vannevar Bush. The NACA had put out books that summarized airfoils characteristics. They gave the profile drag of a great number of airfoil. These were low drag airfoils capable of laminar flow and they had very, very low drag. So Shearer was taking the values of drag, and then just saying that the lift to drag ratio was to take a reasonable lift coefficient and divide the drag into that. He was getting lift to drag ratios that were around 30 and 40 and 50, and he didn't realize that there was another drag that was called induced drag, which was the drag due to lift. You just don't put it in the handbook because it is dependent on the aspect ratio and the speed. Anyway, that was the thing that was wrong with the Hydrofoil Corporation. They calculated the drag wrong and they thought they could get drags that were very, very much lower than they could get. When they built some of their first models, they found that the drag was much higher than they'd thought.

DEVORKIN: Did Bush find you from your authorship of the NACA technical reports, is that how you got in contact?

GILRUTH: No, he found me through the hydrofoil sailboat. Somebody told him there was a kid who built one, and he followed me up and sent Shearer to find me, and he found me at NACA.

EZELL: What did your wife do during the war? Did she continue her flying in any way?

GILRUTH: She did some flying, but she had a daughter and that took a lot of her time, and by the time she got that under control, why, we were building boats and things like that, and she had enough work between her daughter and taking care of me.

MRS GILRUTH: And building the house, they built their own house.

GILRUTH: Yes, we also built our own house. We were always building something.

DEVORKIN: How did Hampton change as the NACA built up during the war? Was Hampton very much dependent upon NACA?

GILRUTH: It was somewhat dependent on it but the shipyard had a bigger influence on it. A lot of the people who lived even where I lived, in old Hampton, worked at the shipyard.

DEVORKIN: This was true during and after the war?

GILRUTH: Yes, I think both have been very helpful, but the shipyard -- of course, is everything to Newport News. Also there is Old Point Comfort, and the Army is still pretty big down in those parts.

DEVORKIN: Let's go back then to the technical questions that you were asking yourself. When the Ram jet wasn't received, what did you see as the goal of your division, or your own future? I'd be interested to know how you thought about your own career in the postwar era, what you thought might be the best thing for you to do.

GILRUTH: Well, I think that quite early in that period, that's '45 -- actually, in '47 we broke the sound barrier, and we were working on that about the time of Wallops Island. In fact, we flew a model of the X-1 at Wallops Island. We were working on supersonic flight of airplanes, and I think that we were also working on re-entry bodies, and we were working on higher and higher Mach numbers, but it wasn't until Sputnik that we really woke up in this country, about things that you could do. We did a lot of work at Wallops Island, even after I left there, on re-entry bodies and measuring heat transfer. We worked on heat transfer even before we realized that there were going to be re-entry bodies and satellites and things like that. We just weren't thinking big enough.

EZELL: What was your working relationship with the folks out on the West Coast, at Muroc?

GILRUTH: Well, quite close. Walt Williams who ran the place used to work for me.

EZELL: At Langley?

GILRUTH: At Langley. He worked in the flight section there, and worked on regular airplanes, flying and handling qualities, that sort of thing. The Muroc people reported through Soulé to NACA Headquarters.

DEVORKIN: NASA headquarters or NACA?

GILRUTH: NACA headquarters. Soulé was the guy at Langley that Williams reported to. By that time Floyd Thompson, who was head of the flight section, became the deputy director of the lab, so that the former flight section people sort of took over running the laboratory.

EZELL: So you were supporting one another, you were feeding information to them, you weren't competing?


DEVORKIN: You mentioned that you were moving up into the multi-Mach number speeds, and examining the characteristics that one would eventually experience with re-entry.


DEVORKIN: There were people in the Navy and some of the NACA such as Haviland and Harvey Hall and others, I think R. P. Haviland was with the NACA for a while.

GILRUTH: I don't remember him. I've heard of Harvey Hall.

DEVORKIN: But not R. P. Haviland.

GILRUTH: That doesn't mean he wasn't with the NACA, I just don't remember.

DEVORKIN: But they were, as were a number of cases like Rand, the early project Rand studies, talking about spacecraft, manned spacecraft and the problems of mainly getting people up into space. But are you saying that nobody was really thinking seriously about problems of re-entry at that time, at least to your knowledge?

GILRUTH: That's right. To me, it seemed like we had been working so hard on the things we were working on, the sound barrier -- and guided missiles -- that really, it wasn't until the Soviets orbited Sputnik that we really said, "my gosh, they intend to take over space and we'd better get going!" It wasn't just us, a lot of people in this country began to wake up.

DEVORKIN: What was the process that led you to become assistant chief of research then in 1952? Was that still at Wallops Island or did you go back to Langley?

GILRUTH: Oh no, I was always at Langley, but I ran Wallops Island. I used to visit there, but I had my office back at Langley. I would have been cut off from things if I had lived over there. Not that it was a bad place to live, it just wasn't a good place for me to live, and still stay in the center of things.

DEVORKIN: How did your duties change, as assistant chief of research?

GILRUTH: Well, Joe Shortal took over, and became head of Wallops.

DEVORKIN: Did you choose him yourself?

GILRUTH: Yes. And then, I was in charge really of guided missiles, structures, and PARD or Wallops Island, those were the three divisions that I ran as assistant director, and I also had my finger in the pie at flight research, because I was an old flight research man, and I used to get called in on some of their problems. Mel Gough was head of that division, and he reported to Thompson.

DEVORKIN: Are you privy to the reasons why you were given that rather significant promotion at that time?

GILRUTH: No, except they must have thought I was the best guy for the job. I really don't think there's any other thing in it than that. And I happened to agree with them.

    At that time I was on the USAF Scientific Advisory Board and the Planning Consultants for the Guided Missile Committee of the Joint Chiefs of Staff. I was also working on the hydrofoils in my spare time.

DEVORKIN: Right at that time, of course, especially when you're sitting on those committees, was the time of the big

re-evaluation. The first of statutory panels like the Research and Development Board, between '52 and '53 was abolished when Eisenhower abolished all the statutory panels, and then it had an effect on the Committee on Self-Propelled Guided Missiles, I imagine. Also, the problem of this reorganization of the Department of Defense heightened the need to come to a one ballistic missile defense system for the United States. I am wondering if you were involved in the decision making process in that committee that was chaired by the fellow from Chrysler, starts with a K - Keller?

GILRUTH: I don't think so. I was on an anti-ballistic missile committee for the Air Force under Guy Stever, and that was different, and I don't know why we folded up our tent, but we certainly did.

DEVORKIN: A lot of interservice committees were folded by Eisenhower in the reorganization and put under the separate Secretaries of the different services.

GILRUTH: That might have been the reason. I don't know.

DEVORKIN: Yes, the Pentagon was reorganized in '52, '53.


DEVORKIN: I'm wondering, when that happened, if that changed the complexion of what your relationships were with the military?

Do you recall any major changes just as you were becoming assistant director?

GILRUTH: No. This was something that happened later in my career, when I became assistant director at the lab.

DEVORKIN: That was about '52.

GILRUTH: Yes, and this ballistic missile defense committee with Guy Stever was much later than that. I don't remember the year. I don't seem to have any record.

DEVORKIN: How would you best typify the work of the NACA during the fifties, between '52 and '58? Were you still exploratory, very much exploratory?

GILRUTH: Well, yes.

DEVORKIN: I know you worked on many of the different missiles that were being developed, like the Northrup Snark, and you were testing them.

GILRUTH: Yes, we tested some. We made some drag tests for the Snark.

DEVORKIN: But were you also doing the same sort of exploratory studies of supersonic flight that you had been doing before at Wallops?

GILRUTH: With the advent of the new wind tunnels and the new transonic wind tunnels, we phased out a lot of that work at Wallops Island because it wasn't necessary anymore. The wind tunnel made more sense than the free flight model.

DEVORKIN: When it became available.

GILRUTH: That's right. So we used Wallops for going into ranges of speed and Reynolds number ranges that you couldn't get to in wind tunnels -- higher speeds, and re-entry things. We didn't have really the incentive for the ultimate re-entry business until the Sputnik became a threat.

DEVORKIN: Were you aware that the Army Ballistic Missile agency had the capability in the fifties to launch something into orbit?

GILRUTH: We weren't thinking in terms of orbit. We had a few guys that were, and I remember, one time we were planning the launching of a satellite, and before we got really into it, one of the people who has long since retired came to me and he said, "Well, Bob, I know you aren't thinking about anything like a satellite, and I'm sure glad you aren't."

    He was one of the high officials in Washington, D.C.

DEVORKIN: You don't remember, or?

GILRUTH: He is a pretty nice guy and I don't want his name to go down in history as that, because it won't do any of us any good.

DEVORKIN: Did his attitude change after Sputnik?

GILRUTH: I don't know. He retired many years ago. I don't really know whether he changed his mind or not.

DEVORKIN: What was your own feeling during the fifties? Did you feel that we should be pushing more into space?

GILRUTH: By the time I realized that there was a space race possibility, I was all for doing it, because I could see what happened when Sputnik went up, and felt that it was some kind of a threat. I felt it ought to be fun to compete. But I didn't feel shook up, that here was a great threat to our style of life, or anything like that.

EZELL: But before Sputnik you hadn't considered whether this was something we should do?

GILRUTH: Well, I'd had talks with the Rand people and people that were going to put up a small satellite, but that didn't do too much for me anymore than it did for Eisenhower. But when you think of putting a man up there, that's a different thing. That's a lot more exciting. And there are a lot of things you can do with men up in orbit. But just to put a little ball up there, that didn't turn me on particularly. I realized that you have to do the little things first before you do the big ones. It didn't take long before you thought we really could put a man in space. We wouldn't have embarked on that project if we hadn't thought it could be done.

DEVORKIN: During the fifties I know, especially during the Korean War, the firing schedules at White Sands became extremely crowded, between both civilian scientific firings and military firings, and there was a time when at least the Civilian Upper Air Panel was in fear of being pushed out.

GILRUTH: That was with the V-2s.

DEVORKIN: Just as the V-2s were running out, with the Aerobees and a few Vikings that were there. Were you ever approached by the Upper Air Panel or any of the other agencies to use Wallops as an actual missile test range?

GILRUTH: I don't remember that. I'm not sure that I would have been the guy to approach at that time.

    Homer Newell was a member of those panels, and he was in NACA then. And so maybe some of his papers would show some of that. I don't know.

DEVORKIN: There was an NACA observer on the Upper Air Panel through many of the years. His name was O'Sullivan.

GILRUTH: Oh yes, he and I worked closely together for several years. He stayed at Langley when I went on to Houston and theApollo program.

DEVORKIN: Could you tell me something about him?

GILRUTH: Sure: An Irishman as there ever was. He was a very bright man, and was always very valuable because he had a very good scientific background.

DEVORKIN: What was his actual background and training?

GILRUTH: He went to Notre Dame, and he graduated in engineering. He had a lot of science, and he swallowed a lot of books. He really was very well-read in most any subject. If you gave him a little time, he would give you a pretty darned good rundown of what you asked him. A very valuable man.

DEVORKIN: Between '49 and '51 approximately, maybe more than that, he was the NACA observer.

GILRUTH: Yes, I know he was observer.

DEVORKIN: Did you give him that job?

GILRUTH: I think so. I think so.

DEVORKIN: Can you recall why you gave him that?

GILRUTH: He was very interested in it. He was very much interested in it, and he liked the kind of people that were on those panels. They all had some scientific depth and he enjoyed being with people like that. He always came back with a good account of what went on and what was important and so on.

DEVORKIN: I recall that the accounts that I've seen are extraordinarily detailed.


DEVORKIN: He'd go on for pages and pages and pages. They were more detailed than the minutes of the panel meetings by far, and there were a number of things that transpired from time to time where he was quite critical of the panel.


DEVORKIN: This is very important to me. This is the part of the research that I'm presently doing. He would reveal all of the internal arguments and the yelling and screaming that the panel would take part in, whereas the minutes, of course, ignored these aspects of the panel completely. Is this sort of thing, did you consider it reliable?

GILRUTH: I'd say it was reasonably reliable. Sometimes he'd be fooled a little bit. Mostly he was pretty good.

DEVORKIN: I know there were a few times where --

GILRUTH: -- something was there. You knew something was there. It might have been a little different slant than he got, but I'm sure that he was absolutely sure himself that he was telling the truth. He was always a truthful guy. But he wasn't always right.

DEVORKIN: The rocket data that was being returned in about '50 to '51 as people were going over the pressure, temperature, density conditions of the upper air, and the rocket region, their values were not in agreement with extrapolations of the NACA standard atmosphere tables. O'Sullivan voiced a very strong concern about this. I wonder if that was something that you were concerned about as well, and followed the problems?

GILRUTH: I don't remember that.

DEVORKIN: It was important for ballistic trajectory calculations primarily. The published accounts of course say nothing of these differences. The only place I've found it are in these reports. But you can't add anything. Can you give me any hint of where I might find more of his reports? I found a few of them in the NASA History Office. They happened to be there. Would he file the reports through you, then they would get sent to some place at the NACA Headquarters? How would they be distributed?

GILRUTH: Well, he would send me memoranda of things that he thought I ought to see, and he wouldn't necessarily send reports to me. He had an office in my division, and I would go to see him when I had a problem that I thought he could help me with, or he'd come and see me if he thought it was something I ought to know. That was about it.

EZELL: Is there anywhere in NASA these reports would be kept?

GILRUTH: Not unless they're somewhere in the files of what used to be PARD.

DEVORKIN: So if I were to look for specific files they would be under PARD probably?

GILRUTH: I would think so, unless they've been put in some kind of storage or something.

EZELL: I think I'd try Langley Archives.

DEVORKIN: Yes, but the question is, what division or subdivision and code number would I look under depending on how they'reorganized?

GILRUTH: He worked with this great big balloon.

DEVORKIN: Project Helios?

GILRUTH: No, he actually orbited a balloon that had a special name, you could see it go over --


GILRUTH: Echo, yes, that's it.

DEVORKIN: He got involved in that?

GILRUTH: That was his project, it was his idea. That was his thing.

DEVORKIN: Do you think he's still around?

GILRUTH: No, he's dead. He died many years ago. He's got a couple of boys that are just like him.

DEVORKIN: By just like him, you mean?

GILRUTH: I have not seen them for many years and they were young boys at that time.

EZELL: We were laughing because we were with a group of people who knew they called him "Wild Bill O'Sullivan".

DEVORKIN: You said he had to be made an office of one, he couldn't work with other people.

GILRUTH: That's right.

DEVORKIN: Did he have trouble getting along with people?


DEVORKIN: Was he suspicious of other people?

GILRUTH: I don't know, but there are some people like that. There's no harmony there with other people.

DEVORKIN: Actually what you've given me is very helpful, because his reports are incredible.

GILRUTH: Well, he was pretty bright. He was a good old Notre Dame man, and he was certainly a good hard working guy. You gave him a job, he was sure to do it thoroughly.

DEVORKIN: We've gone over our three hour limit at this point.

EZELL: It's a good place to stop anyway, we can pick up with Sputnik the next time.

DEVORKIN: How do you feel about that?


DEVORKIN: Is there any part of your NACA years that you feel we should cover in greater detail at this point?

GILRUTH: I don't know. I'd have to think about it. Incidentally, is there any chance of getting transcripts of this?


GILRUTH: Is there a transcript of the last one?

DEVORKIN: Yes, but we would prefer to edit ourselves first, rather than give you a raw copy.

COLLINS: I think we can give him a raw copy.

EZELL: These are the Rowland volumes that we've been referring to, he did the NACA history for NASA.

GILRUTH: Oh, how nice.

EZELL: It's a different cut from what Henson's taking at Langley. The first volume is narrative and the second volume is documents. Organization charts. That sort of thing. So this would probably be just as useful as a text.

DEVORKIN: What we'd be very interested in doing with you, as your time allows, is, if you do have time to read through parts of the Rowland book or as much as you want, if you have a feeling you should annotate them, either on tape with us or simply in the book or make notes, we could use the oral history as a vehicle to enhance or capture your reactions to Rowland's history or to Henson's history. We do this with others.


DEVORKIN: James Webb has been annotating a number of histories that have been written, and that's proven to be extremely valuable, and we would hope that we'd be able to do the same with you.

GILRUTH: Yes, sure.

1 Gilruth, Report 755.

2 Gilruth Report 711.

3 Robert Gilruth, "Appraisal of German Research During the War," 1946. GWS Oral History Project, working history file, National Aur and Space Museum, Washington, DC.

Gilruth 1 || Gilruth 3

Rev. 09/06/96

© 1996 National Air and Space Musuem