Collection Item Summary:
Bill Bennett and his Delta Wing hang gliders played a significant role in promoting hang gliding into a popular sport enjoyed by thousands of people worldwide in the late 1960s and early 1970s. Bennett's first gliders were actually manned kites, such as the Model 162. He based these designs on a flexible wing pioneered by Francis Rogallo. This inventor developed his wing while working for NASA during the early 1960s. The space agency wanted a controllable recovery system for Gemini and Apollo capsules (see NASM collection) as an alternative to unguided parachutes. The difficulties the agency experienced trying to recover the Mercury capsules (see NASM collection), and the near tragedy that followed Gus Grissom's splashdown in July 1961, no doubt encouraged NASA to develop alternative capsule recovery systems.
Bennett produced ten different models of the Rogallo hang glider. Each was named for the length of the keel bar in inches, or the overall length of the aircraft. The initial tow-kite models were called the 162, 174, 186, 198, and 210. The kites with longer keels had larger weight capacities. The Model 162 could safely support a maximum pilot weight of only 59 kg (130 lb), while the Model 210 could accommodate a pilot weighing up to 113 kg (250 lb).
Collection Item Long Description:
Bill Bennett and his Delta Wing hang gliders played a significant role in promoting hang gliding into a popular sport enjoyed by thousands of people worldwide in the late 1960s and early 1970s. Bennett's first gliders were actually manned kites, such as the Model 162. He based these designs on a flexible wing developed by Francis Rogallo and wife Gertrude and patented in 1951. NASA became interested in the Rogallo wing after the Soviets launched Sputnik in 1957. The space agency tried to adapt the Rogallo wing into a successful recovery system for Gemini and Apollo capsules as an alternative to unguided parachutes. Making the Rogallo wing a safe and practical recovery system took too long and the agency chose instead to use unguided parachutes to land its capsules in the ocean.
Rogallo designed his flexible wing to allow the astronauts to deploy it like a parachute at subsonic speeds during reentry, then 'fly' their capsule to a specified touchdown point and planners considered touchdowns on land for capsules equipped with Rogallo wings. NASA first tested the wing on the Parasev (see NASM collection) research vehicle in 1962. During early test flights, automobiles towed the Parasev across the Edwards Dry Lake test range in California. Later, aircraft towed the Paresev to altitude and glide tests were conducted. NASA eventually discarded the Rogallo recovery method in favor of simpler, more reliable and more economical parachutes, but publicity from the Parasev test sparked interest in the design among several tinkerers, including the Australian, John Dickenson. Dickensen wanted a simple and less-expensive alternative to the classic, fixed-wing gliders and the complicated launch procedures required to fly them.
Dickenson first flew his version of the Rogallo wing in 1963. His kite carried water skiers aloft, towed behind a powerboat. The Rogallo wing glider was much safer and more stable that the traditional ski kites with flat airfoils. By 1966, Dickensen was selling his adaptation of the Rogallo wing ski kite commercially, and in 1967, he introduced fellow Australian Bill Bennett to the booming sport of flying ski-kites. Bennett quickly set altitude records in his own variations of Dickenson's designs. By 1969, Bennett had moved to California to sell commercial models under the Delta Wing name. The extreme nature of the sport appealed to the freewheeling culture of the late 1960s, and across America, Bennett's towed kites quickly grew in popularity.
Bennett's early Rogallo designs consisted of two high-strength, heat-treated, anodized aluminum tubes bolted together to form a cross, and two aluminum tubes bolted to the one end of the cross, or 'keel' tube, to form two leading edges. The leading edges formed a delta wing with a relatively narrow convergence angle of 80 degrees. A Dacron 'sail' was attached to this frame to from the airfoil. A Nylon-webbed seat supported the pilot who controlled his simple aircraft by grasping a control bar and shifting his weight side-to-side and fore-and-aft.
Bennett produced ten different models of the Rogallo hang glider and named each for the length of the keel bar in inches, or the overall length of the aircraft - 162, 174, 186, 198, and 210 inches. The kites with longer keels had larger weight capacities. The Model 162 could safely support a maximum pilot weight of only 59 kg (130 lb), while the Model 210 could accommodate a pilot weighing up to 113 kg (250 lb).
Bennett became a spectacular promoter of the infant sport of hang gliding. He stirred publicity for his tow-kites when he flew near the Statue of Liberty on July 4, 1969, released his towrope and circled the monument twice, landing at its base. The Delta Wing kites were also popular attractions in water-ski shows at marine theme parks, and at airshows. But Bennett's greatest publicity achievement involved Hollywood. In 1972, he was hired as the stunt pilot to double for actor Roger Moore playing James Bond, Agent 007, in the film "Live and Let Die." Naturally, Bennett flew a Delta Wing glider. His flying sequence appears about halfway into the film, when a cabin cruiser tows Agent 007 over Mr. Big's island hideout. Bond releases the tow cable and glides quietly to a landing without arousing any of Mr. Big's thug guards. This mainstream exposure gave another boost to the popularity of Rogallo wing hang gliders.
By 1972, many hang glider pilots were tired of depending on cumbersome, sometimes dangerous, means for towing their gliders aloft. Downhill snow skiing offered one successful, but also frequently risky, alternative. To extend his glides, Bennett developed a portable power source. It consisted of an 18 horsepower McCulloch gasoline engine driving a pusher propeller encased in a wire cage. The pilot strapped this contraption to his back, pulled a rope handle to start the engine, and then attempted (often successfully) to take off. These experiments eventually led to the modern powered ultralight airplane.
In 1973, Bennett made several foot launches from elevated terrain. Other people had the same idea and soon hillocks and seaside cliffs were crawling with fledgling pilots attempting to foot-launch a variety of aircraft, from factory-built Delta Wing gliders to crude homebuilts fashioned from plastic tubing. Much of this activity happened in California, where the counterculture movement happily embraced it. Frequent crashes made the learning curve steep and painful, but when 1973 ended, Bennett and others were successfully gliding and even soaring their Rogallo wings using thermal updrafts and ridge lift.
Enthusiasm for hang gliding continued to climb and pilots posted new duration and altitude records on a weekly basis. Bennett developed five lighter variations of the tow-kites specifically adapted for foot launching. The Rogallo wings with 80 or 90-degree nose angles became known as standard Rogallos. Soon the modified, or hybrid Rogallo, appeared. It consisted of much higher nose angles and longer wingspans, and steel wires braced the whole structure to increase strength and improve performance. This version proved much safer than the standard Rogallos, which were highly unstable even in moderate winds and turbulent conditions. On the early standards, the sails attached to the leading edges and keel tube only, leaving large areas of material loose. All went well if the glider pilot maintained stable forward flight. The vortex of air created by each swept leading edge billowed the halves of the sail so that they held their concave shape. But in turbulent air or a stall, one or both sides of the Rogallo wing could deflate and collapse, or 'luff,' causing the glider to dive out of control. As foot launching off rugged, elevated terrain became more popular, hang gliding fatalities rose dramatically and accelerated the transition to modified Rogallo designs.
After 1975, most hang glider pilots were starting to fly modified Rogallos. Bennett introduced the Phoenix hang glider series (see NASM collection). These and other modified Rogallo aircraft helped to transform hang-gliding from a reckless game into a more legitimate sport. Without Bennett's flair for promoting hang gliders and his clever adaptations of the Rogallo wing, the growth of hang gliding would have proceeded much more slowly.
Bennett donated a Model 162, along with a number of his later modified Rogallo models, to the National Air and Space Museum in 1984. Nothing is known about the flight history of this particular Delta Wing Model 162.