FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1983
1983 - 1524.PDF
OSHKOSH 83 Rutan canards stay ahead Out of some 500 homebuilts on display at Oshkosh, nearly 70 were designs by Burt Rutan, not counting some further 15 tandem-wing light weight Quickies, in whose design he also played a major part. Also prominent was his Solitaire self-launching sail plane, plans for which are now available, and the Defiant centreline-thrust twin, which he has now decided to market. The invasion by VariEze, and its later development the LongEz, has been achieved in six years, since the first home- built VariEze appeared at Oshkosh. More than 500 of the series have been com pleted around the world, and 1,700 of the larger and better payload-carrying LongEz are said to be under construction. Rutan's composite achieve ment is still one of the major light aircraft landmarks for many years. No production two-seater has this sort of performance on a 115 h.p. Lycoming — a maximum cruise of more than 160kt with two people for more than 1,100 n.m., and with the inherent stall protection of Rutan's thoroughly-designed canard configuration. Cost to the homebuilder can vary from about $6,000 to $14,000, depending on how many pre fabricated parts are bought, and on the life of the engine. Possible long-term devel opments include the inves tigation of nosewheel steering to improve crosswind take-off performance, and variable- pitch propellers. The Solitaire self-launch ing sailplane won the Soaring Society of America's design competition last winter for 486 homebuilt sailplanes, and it has been on the homebuilt market for a month, with some 40 sets of plans sold. Rutan says that he wanted real soaring and penetration for cross-country cap-ability from the outset. He aimed at a glide ratio of 1 • 32, so that the Solitaire could be flown at least against the US Schweizer Sprite, plus the slow-speed safety ability to fly at full-aft stick without risk of spinning—as in all of his designs. These two aims have certainly been achieved, and other big advantages from the pure sailplane aspect are good crosswind or downwind land ing capability from the tandem fixed-wheel landing gear, and the fact that the pilot is sitting directly on the e.g., needing no compensating ballast if light in weight. Engine retraction was the biggest problem in Solitaire's development, and several en gine types were rejected because retraction proved impossible. Final choice is the two-stroke Italian KFM 107E, which develops 23 h.p. at some 6,000 r.p.m., is electrically started, and can be wound in or out by a small electro-hydraulic motor. Re traction or extension can be completed in less than lOsec, and at Oshkosh we saw Rutan's colleague Mike Melvill make a high-speed into-wind run with the engine fully retracted, then pull up and have the engine out and running by the time he was positioned downwind for a low level circuit. Take-off roll is around 700ft, and climb rate some 300ft/min. Practically all flying to date has been from the Rutan base at Mojave, which in mid-summer can have a 7,000ft density alti tude. Minimum sink is quoted as 150ft/min at some 40kt, and best L/D 1-32 at 50kt. Rutan says that, when flown against a Sprite, the Solitaire loses out slightly at low speed Left Run and break for the Defiant and LongEz. Below Solitaire under power (since wing loading is higher), but gains at high speed. The unusual "spoilflaps" produce no trim changes and can be deployed at the Vne of 115kt. It has been static- tested to 7g, when the wing- tips deflected 47in without failure. Rutan's remarkable Defi ant, which adds twin-engined capability to the Canard advantages, was first at Oshkosh in 1979. While he seriously considered devel oping it as a production aircraft, Rutan has now launched it on the homebuilt market in conjunction with Alaskan-based Fred Keller, who has constructed a second aircraft. With both of its 160 h.p. fixed-pitch engines running, Rutan's four-seat Defiant (which has logged l,000hr to date) cruises about 30kt faster than any contemporary light twin. It was once flown for more than 15hr non-stop on standard fuel, and to 28,000ft. But it is in the engine-loss-on- take-off situtation that it is even more remarkable, since it still has a positive climb rate at full aft stick, and no asymmetric problems. The second aircraft inevita bly has a few detail improvements and has been "optimised for the home- builder". Engines from 150-180 h.p. will be accept able. Rutan is still working on plans for sale in 1984. FLKIHT International, 20 August 19m
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
