Schapel SA-882 Flying Wing prototype

The SA-882 is a flying wing which was designed and built to research the overall aerodynamics, control and flying characteristics of a tailless airplane configuration.

"The Schapel Wing is powered by a turbo-charged Mazda, 2 chamber, rotary engine. The 3-bladed propeller is ground adjustable and is driven by a 40-inch long drive shaft. Propeller 2:1 speed reduction is accomplished by a helical gear speed reducer. The engine gave them some problems during the dyo testing phase, but a successful combination was finally developed.

The aircraft was built in female molds using an epoxy system, vaccumed, and cured at 240 degrees F. in an oven. The upper and lower surfaces are a foam sandwich with a three spar system out to the landing gear position and then two spars out to the tip. The wing has five ribs per side and uses a non-laminar flow airfoil of his own design with a very low pitching moment. The wing has a lot of twist between the root and tip, with about 9 degrees negative by the time you reach the tip. This was designed to achieve a zero
pitching moment, which has since been confirmed through the flight testing. Max CL came out to about .85, and was driven by the fact that all the actuation mechanisms had to be enclosed.

The actual construction involved using unidirectional material, laid up at different angles as required by the results of a computer analysis. They built a male plug, a set of one piece female molds for everything and, then the PVC sandwiched skins constructed. This type of construction gave it about a 1300 lb. empty weight, with a fuel capacity of 57 gallons right at the CG. The spars were made up separately, then added to the laminated lower skins along with the ribs and then bonded all together. The upper skins, in their molds, were then bolted on-top of the low portion so a spar cap could be cast to measure the thickness between the spar and upper skin. Once the skin was constructed, the whole thing was bolted together and put in the oven for curing.

Rod added a comment about making sure you put a steerable nose gear on any plane like this, which he had not. Low speed controllability during the initial phases of takeoff required using a lot of brakes, since the drag rudders were ineffective. This was due to them being at the MAC rather than the wingtips so the pitching moments wouldn’t be changed during flight.

Several things Rod said he would change if he did it again were: put the drag rudders out at the wingtips; instead of having separate elevator and ailerons he would combine the two, and; he felt it would be much simpilar to put a jet engine (about 400 lbs thrust) in it versus the rotary."