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C o n s u m e r , H o m e a n d R e c r e a t i o n
Lightplane Wing Design
he airplane pictured is a two-place Venture, a "homebuilt" assembled by the buyer from a kit of components
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designed and manufactured by Questair, Greensboro, North Carolina. It is a dents Holly Meyer Ross and Bruce Owens, high performance lightplane that can cruise advised by Dr. John N. Perkins, associate head at more than 250 knots and climb at 3,000 of the Department of Mechanical and feet a minute. Additionally, it has excellent Aerospace Engineering, joined with Langley low speed characteristics and enhanced safety Research Center to advance the database of due to NASA technology incorporated in its the antistall technology and extend it to air- unusual wing design. craft with high aspect ratio wings.
The Venture has a high aspect ratio Ross, Owens and Perkins, together wing, long in span in relation to its chord, with NCSU lecturer Robert J. Vess and with relatively high lift and low drag. For that Langley engineer Long P. Yip, spent seven reason, it was selected as the airplane to be months of 1987 working on the Venture pro- employed in a joint ject. They performed wind tunnel and radio NASA ANTISTALL TECHNOLOGY IMPROVED NASA/North Carolina State controlled model tests at Langley, analyzed THE SAFETY AND PERFORMANCE OF A NEW University (NCSU) research the results and recommended a wing modifi- HOMEBUIL T AIRPLANE project involving new tech- cation for the Venture.
niques for preventing aircraft The modification consisted of a stall at high angles of attack (the angle droop in the leading edges of the wings near between the wing and the air through which the tips, plus two "slots" cut into the leading it is moving). edge of each wing. The slots create small A stall, which can cause loss of con- whirlpool-like airflows called vortices that add trol, occurs when the airplane loses lift due to energy to the airflow and prevent separation.
disturbance of the smooth airflow over and Wind tunnel tests showed that the under its wing. At high angles of attack, the NCSU/Langley droop/slot combination airflow breaks away, or "separates" from the delayed airflow separation and improved wing surface and causes stall. control, thus providing more usable lift than The standard industry method of the stall strips. Flight tests with the Venture countering separation is the addition of "stall confirmed the effectiveness of the droop/ strips" that fence and direct air to improve the slot configuration.
wing's stall characteristics, but this technique The modification was adopted on the involves some loss of wing lift. NASA had Venture prototype, which was further tested developed another solution that employed by the company; the airplane subsequently drooped wing leading edges to bar separa- set 10 world speed records for small single tion; experimentation, however, was incom- engine aircraft. The homebuilt is now in pro- plete. The method had been tested extensive- duction and commercially available. Questair ly on conventional moderate aspect ratio officials state that the NCSU/NASA work en- wings but much less work had been done on abled the company "to establish a new stand- high aspect ratio. ard in stall departure/high angle of attack NCSU, in the form of graduate stu- flying qualities for general aviation aircraft.