Aquila - DXF Laser cut Files

About this Plan

Aquila. Radio control sailplane. Wingspan 99 in.

The wing chord is 9in to increase Reynolds number and provide increased wing area. We feel that these factors are more important than the reduction in induced drag from higher aspect ratios. The wider chord provides greater visibility at high altitudes since the width of the wing is more significant than the span. The increased area also provides higher launches as it will carry the weight of the launch line better than the smaller area ships. (As long as all models are flown on the same launch equipment and the launch device is sized to lift the big ships the smaller ships are at a disadvantage.)

The airfoil is a medium thickness. flat bottomed section with a low entry point. The leading edge radius is fairly large to provide a soft stall and the high point is located at 30%. Our experience shows that this type of airfoil performs better than the undercambered sections under all conditions except dead calm. Since some wind seems to prevail during most contests, the ease of building and covering far offsets the minor loss of performance under atypical conditions.

The wing planform with constant chord center panels and double tapered tips is nearly as efficient as an elliptical planform and much easier to build and repair. Positive Hoerner tips are utilized to reduce tip vortex losses and increase effective span. This style tip is used on the full-scale Duster sailplane and discussions with Hank Thor, the Duster designer, while researching a scale model convinced us that this type of tip would improve model performance. Polyhedral is used because of the superior turn characteristics over Vee dihedral. The change in leading edge radius on the tip panels eliminates tip stalling and avoids the loss of lift caused when wash out is used for this purpose.