Status: company-owned prototypes / homebuilt aircraft
Type: self-launching single place canard sailplane with auxiliary engine
Powerplant: 1 x 23 bhp* KFM 107E (*at 6000 rpm)
First flight: 28 May 1982 (first prototype), December 1985 (1st homebuilt)
For a long time soaring was an exclusive sport requiring a special license and training. Soaring in a glider of enough performance to allow the average pilot to feel the true thrill of 'engineless' flight was expensive enough to severely limit the number of people who entered the sport. The Soaring Society of America had recognized the fact that other segments of homebuilt aircraft were experiencing great interest and activity on the part of designers and the general public, while the sailplane market was not getting its share of the attention.
To correct this, the SSA issued a challenge in the form of a contest: Develop a self-launching sailplane capable of take off and the ability to climb to altitude without the use of a tow plane. The new design could be flown without the special license required of a sailplane pilot, just a private pilot's license. The aircraft must be easy to fly, as well as quick and easy to build. Strict rules were set up and an actual structural test of the finished aircraft was required. There were about 55 official entries in the SSA's contest, with fly-off and evaluation of all entries planned for the summer of 1982.
Burt Rutan had always wanted to design a sailplane, so when the opportunity presented itself in late 1980, he began designing one. In April 1981, when the interest in ultralight and light sport aircraft reached an all-time high, Rutan Aircraft Factory announced that they had entered the Soaring Society of America's contest to design and build a home-buildable single-place, self-launching sailplane. The Model 77-6 Solitaire was designed around these goals and achieved these and more. The Solitaire would also shift the public attention away from the Rutan Aircraft Factory’s top secret experimental airplane, the Grizzly.
The Solitaire was a single-place sailplane with the intended capability to self launch, with a fixed engine and a retractable propeller. It had a 12.5 meter wingspan, and the tandem-wing configuration allowed the pilot to sit at the cg, eliminating the cg shift due to pilot weight that is common with standard sailplanes. The engine, with electric starter for air starting, erected from and retracted into a bay in the forward fuselage by means of electro-hydraulic power. The canard configuration was intended to make the ship virtually stall-proof as the canard stalls before the main wing, causing the ship to pitch nose-down and preventing the main wing from stalling. That, however, did not mean that mishandling could not cause very high sink rates.
The main wing had trailing edge flaps which also operated as spoilers by the leading edge coming above the top surface of the wing when deploying. The unusually efective "spoilflap" trailing edge surfaces provided good glidepath control. With the engine folded, it had a L/D of 32 to 1, giving it true soaring capability. The engine could be deployed and restarted inflight using its electric starter. The canard concept resulted in high resistance to inadvertent stalls and spins. Its 'spoilflap' descent control system were acclaimed as "excellent" by all evaluators, providing crisp, variable glide path control without trim upsets. Unlike conventional sailplanes the pilot sat within the allowable cg range.
Initially, Burt settled on the Zenoah engine, however, he changed to a Robin within a few weeks and, still later, switched to a single cylinder 215cc Cuyuna. Of seven or eight sketches, Burt liked the canard or tandem wing, with the canard mounted right on the forward end of the fuselage, with its leading edge in line with the tip of the nose. Construction on the Solitaire began in December of 1981 and was completed in early 1982. On May 28, 1982 the Solitaire made its first test flight, piloted by Mike Melville. The Solitaire handled well and performed as expected. Later, the engine was removed and the aircraft was test flown as a sailplane. Burt worked with the local FAA to get the new Grizzly signed off as the tow plane and arranged for himself to be checked out as a tow plane pilot. Burt and Mike towed many flights with the Grizzly, some up to 10,000 feet to obtain L/D data and to open the envelope.
At the Homebuilt Sailplane Association flyoff held in Tehachapi, California, on September 6, 1982, pilots Einar Enevoldson (famous NASA test pilot), and Walt Moonie evaluated the canard Solitaire. One pilot would fly the Solitaire and the other a Schweitzer I-36. Performance between the aircraft was similar at low G's, but when the pilots landed, the one in the Solitaire claimed it was really rough. The I-36 pilot claimed it was smooth. The pilots traded places and the same thing happened with the canard pilot claiming rough air. As Walt Mooney later explained, "the canard enters the gust first causing the nose to pitch up and then the wing to push the aircraft up." With a conventional aircraft, the aircraft only translates up and down since the tail keeps it level. Furthermore, when making high banked turns in the Solitaire the sink rate would increase greatly. Still, the Solitaire was so good a design that after the judges studied all the entries, they unanimously declared it the winner.
Task Research manufactured and marketed the prefabricated fiberglass parts for the kit. These parts were the most advanced, state of the art components offered to homebuilders at that time. The fuselage halves consisted of skins of prepreg fiberglass carefully oriented for optimum efficiency, with Nomex honeycomb cores and utilized high tech film adhesive to bond the sandwich together. The main wing spars had “S” glass roving spar caps and were molded in metal molds. The spars and fuselage halves were required items since they were not readily homebuild-able. Task Research also supplied the seat pan, the canopy in its frame, and the turtledeck pre-molded. In addition, optional pieces included prefab fuselage bulkheads, wing root fairings, wheel fairings, wingtips, and even pre-hot wired foam cores for the wings and canard.
The Solitaire used the proven materials and methods pioneered by Burt Rutan and used in the VariEze and Long-EZ, two of the most successful aircraft ever designed for the homebuilder. The wings were special uni-directional fiberglass cloth and epoxy resin. They were built using the moldless composite technique developed in the VariEze and consisted of prefabricated 'S' glass spars and a solid foam wing core. The fuselage came as two prefabricated halves. The bulkheads were available prefab and the wooden fixtures and templates could be made available premanufactured. The canopy came installed in the frame and the turtle deck was also available prefabricated.
All of the metal parts and complete landing gear components were available premachined. The premolded parts were of aerospace quality. Construction consisted of prepreg skins with a honeycomb core and an adhesive film to bond them together. These were then vacuum bagged and cured in an oven. In short, the aircraft had more prefabricated parts than any previous design from Rutan Aircraft Factory. Of the available prefabricated parts, the builder could buy all or as few parts as he wished.
Depending on the success of fligh testing, the Solitaire was to be offered for homebuilder construction and marketed similarly to the Long-EZ, not as a complete kit, resulting in considerable cost savings to the builder for materials. Rutan's company estimated that an average builder, purchasing all the available parts could build the aircraft in 400 hours at a cost of between $7000 and $9000. When the quality of parts and the ease of building was considered, the value of the Solitaire would soon become apparent. Solitaire was conceived more for fun than competition, and there was always the motor to do a 'save' or get home with. Robert Matheny of San Diego, California was the proud owner of the first customer built Rutan Solitaire. Robert spent two years and three months building the Solitaire as a pure glider. The first flight was in December of 1985 behind a tow plane. After five hours of flight time, the glider was returned to Robert’s shop for engine installation. In 1986, Robert Matheny donated the Solitaire to the EAA AirVenture Museum where it now resides in the company of other innovative Rutan aircraft.
Solitaire builder Herb Abrams spoke of the aircraft in emphatic terms: "Solitaire is easy to fly, self launching, is immensely less stressful and more satisfying than airplane tow, glide path, and speed control and landing is easy and precise with the spoilflaps, taxiing and ground handling is a breeze and the engine operation is flawless. I was even able to extend and start the engine during the landing rollout! Yes, the prototype Solitaire I flew had rather marginal rate of climb but the new KFM engines produce more power, the just issued engine installation plans provide a few more inches of propeller and a longer prop engine installation I am developing, all promise to improve the climb rate. In addition, I am sure our Solitaire builders' airplanes with the improvements already incorporated in the plans, and perhaps some of their own, will perform even better than the prototype. In a word Solitaire does all it is intended to do and in an easy way to make soaring safer and more convenient for us sport soaring enthusiasts."
And yet, though a promising design, the Solitaire was not a success, and with the market for do-it-yourself gliders being small, only a handful were built. The major pre-manufactured bits were considered to be a bit too hard for the 'normal' back-yard constructor. Moreover, the Solitaire was an awful thermalling sailplane, as shown by a paper published by Einar Enevoldsen and the late Marta Bohn-Meyer, who had both test-flown it. Two further problems may have beset Solitaire: the lawsuit against Rutan over the Microlight design, widely considered to have been unfair, malevolent and frivolous (although it was ultimately dismissed, it nevertheless had an extreme negative impact); then Rutan's subsequent withdrawal from the market. Also along the way, there were problems with a fabricator/supplier, which certainly didn't help. Two other homebuilts later used the Solitaire's fuselage: one was the Silhouette, which enjoyed limited success, and the other was the one-off Skyblazer.
Population: 8 [N81RA, N142SD, N214RA, N691LP, OY-XRT, PH-1312, etc.]
Crew/passengers: 1Main sources:
- EAA's AirVenture Museum