Windecker Eagle I
The Windecker Eagle I has the distinction of being the first all-composite aircraft to receive FAA certification. The Eagle was the product of several years of experimentation by Dr. Leo Windecker and Dr. Fairfax Windecker, working with Dow Chemical Company, to develop lightweight fiberlass reinforced plastic structures for aviation use. A flexible, non-woven glass fiber material called "Fibaloy" was the result and led to the Windecker X-7 prototype.
In 1969, the Eagle I, a four-place, low-wing monoplane, received FAA certification only after building in a 20% over-designed airframe to make up for nervousness about the strength of composite materials. Six Eagles were completed but it was never able to break into the 1970s market that already held several well-established production aircraft. Nevertheless, it is a testament to the pioneering work in the field of composite materials.
Gift of Tom Hairston and the Dow Chemical Company
White with gold trim; first all-composite aircraft certificated by FAA; fiberglass, resin structure; 1967.
- Country of Origin
- United States of America
- Windecker Research Inc.
- Overall: fiberglass monocoque
- Wingspan: 9.7 m (32 ft.)
- Length: 8.7 m (28 ft. 6 in.)
- Height: 2.9 m (9 ft. 6 in.)
- Weight, Empty: 975 kg (2,150 lbs.)
- Weight, Gross: 1,540 kg (3,400 lbs.)
- Engine: Continental IO-520-C
The Windecker Eagle I has the distinction of being the first all composite aircraft to receive FAA certification and is representative of pioneering work in the field of composite materials. The Eagle was the product of several years of experimentation by dentists Dr. Leo Windecker and his wife Dr. Fairfax Windecker, working with Dow Chemical Company in their quest to develop lightweight fiberglass reinforced plastic structures for aviation use.
The Windeckers started research in 1958 on fiberglass-reinforced plastic structures, as they were particularly interested in the weight-saving possibilities for an aircraft. They soon had the support of the Dow Chemical Company, and the work of the Windeckers and Dow's Dr. Malcolm Pruitt resulted in a patented flexible, non-woven glass fiber material called "Fibaloy." The material had excellent properties that permitted it to be molded into complex shapes and it was easily glued and machined, making it ideal for many aircraft manufacturing and other applications. To test their new Fibaloy material on an aircraft, they built wings for two Monocoupe 90 airplanes. These improved wings resulted in a substantial increase in top speed and a significant reduction in the stall speed of the Monocoupes.
With these encouraging results in hand, Dr. Windecker formed Windecker Research Inc. in Midland, Texas, to develop an all-new composite airplane with Fibaloy material. In October 1967, the company test flew the Windecker X-7, a four-place low-wing cabin monoplane with a fixed tricycle landing gear and a 290 hp Lycoming engine.
The second airplane, the true prototype of the Eagle I production model, featured a redesigned wing, retractable landing gear, and a 285 hp Continental engine. It made its first flight early in 1969 but was destroyed on April 19, 1969, while performing the last of the required series of spin tests. Having determined that the aircraft would not recover from the spin, test pilot Bill Robinson was bailing out when his foot caught in the door jamb. After several tries he was able to slip out of the shoe, clear the airplane, and pull his parachute ripcord just in time, while the airplane crashed down below. It was determined that the dynamic imbalance under certain spin conditions was attributed to an end weighted nose-and-tail weight distribution that made the aircraft spin faster and faster. This, when coupled with aerodynamic blanking of the vertical fin while in spin attitude, made spin recovery impossible under the extreme aft center-of-gravity test conditions.
On the next airplane, a thorough weight reduction and redistribution program was implemented and a ventral fin was added to compensate for the aerodynamic blanking encountered. Because of its unfamiliarity with plastic airframes, the FAA imposed an overdesigned airframe restriction of 20%. This airplane went on to complete the FAA certification tests but not before the Eagle became the most spin tested airplane in existence. The Approved Type Certificate (#A7SW) for the Eagle I was issued in December 1969. This second prototype aircraft was displayed briefly in the Arts and Industries Building of the Smithsonian in 1970.
The Eagle I, model A-7C, was a four-place, low-wing monoplane of Fibaloy construction and a retractable tricycle landing gear. The 285 hp six-cylinder Continental engine and either a McCauley or Hartzel two-blade constant speed propeller offered performance equal to that of the Beech Bonanza and faster than that of other contemporary aircraft. Windecker built nine Eagle airplanes including the two prototype test aircraft, six civilian versions and one for the US Air Force that was designated the YE-5. The Air Force really wanted the YE-5 airplane so that it could test the radar reflectivity and stealth characteristics of the all-composite construction. The Air Force transferred it to the U.S. Army which wanted to test it for possible use as a utility airplane. The airplane was then sent to the Army Aviation Museum for display. There was also a seventh civilian Eagle I being constructed, but it was never completed before the company went into receivership.
The 1970 economic recession was a difficult time for the aircraft industry and Windecker had already invested more than $20 million in the development of the Eagle. When he could no longer find financial backers, the company closed its doors. In 1977, Gerald Dietrick bought the assets of Windecker and, in 1979, formed the Composite Aircraft Corporation to build the Eagle I. Dietrick's company never went into production because the Eagle was in direct competition with the well-established metal models from Beech, Cessna, Piper, and Mooney. Because of its revolutionary construction, it was not possible for Dietrick to price the Eagle as low as the Beech Bonanza, which had been in production for several decades ($112,000 vs $95,000). Also, during the 1980s, the light airplane market experienced a severe depression and because of a surplus of aircraft and product liability litigation that halted production of several light aircraft models. Shortly though, composite aircraft arrived and stayed on the aviation scene.
The Museum's Eagle I, serial number 6 and N4197G, was completed at the Windecker factory on March 3, 1971, and, as a Dow aircraft, flew a total of 454 flight hours along with its original Continental engine. Dow Chemical Company, Freeport, Texas, flew the Eagle I to Hyde Field in Clinton, Maryland, on July 23, 1985. The aircraft is stored at the Paul E. Garber Restoration and Storage Facility in Suitland, Maryland.