RC Airplane Design

 The Ultimate Guide to RC Airplane Design. Learn How to Design and Build your own RC Airplane from scratch...

RC Airplane Design Articles

• How to Design a Blended Wing Body (BWB) RC Airplane

• How Aspect Ratio affects the Stall Angle of Attack of RC Airplane

• How Aspect Ratio affects the Wing Lift Coefficient of RC Airplane

RC Airplane Design Tools

How to Calculate Aspect Ratio (AR) of RC Airplane

General RC Airplane Articles

• What is RC Airplane Hobby

• What are the types of RC Airplanes

• What are the different types of RC Airplane Kits and plans

• What are the parts of RC Airplane

• What are RC Airplane Control Surfaces

• What are RC Airplane Building Supplies

• How to Build a RC Airplane Workshop

• What is RC Airplane Field Equipment

• How to take care of RC Airplane Gas Engines

• How to take care of RC Airplane Propeller

• How to check RC Airplane Center of Gravity

• How to check RC Airplane for Strength

• What are Proper Building Techniques for RC Airplane

RC Airplane Pictures

How to Design a Blended Wing Body (BWB) RC Airplane

The BWB can offer very good advantages over a tube and wing, but requires about 5 times the aero analysis to get it.  This is because the wing’s airfoil stack varies radically from root to tip.  If you have a copy of Mark Drela’s AVL code I would recommend using this to determine the best airfoils and twist needed to get good performance.  Here are the Guiding principles to design blended wing body BWB RC Airplanes,

1. Near elliptic spanload at cruise (Inviscid e =~1 without winglets and ~1.1 to 1.2 with winglets)

2. Use normal airfoils outboard (normal thickness 12-16%).

3. Use reflexed airfoils inboard (increased thickness 18-22% is AOK).

4. blend very smoothly across the kink in the planform.

5. Use ~25-35 degrees of wing sweep to get pitch and yaw stability (AVL stability estimates are good).

6. Aim for a Static Margin of ~25%mac

7. In AVL adjust chord and twist to locate the stall-critical station inboard of ~70% semi-span for good stall handling.

This is a very iterative process, but if done correctly you will get higher CLmax and L/D that a tube and wing design.

Also, I use a trapezoidal wing definition for Sw, ARw, and mac.  So the extra chord in the Centerbody is not included in the reference wing area.  Using this definition, a typical CG fro good stability is -10%mac (yes that’s 10%mac ahead of the mac’s leading edge), way forward of a typical airplane.  Also this trapezoidal wing should have a taper ratio of 0.8 to 1.0 to get stability with good stall characteristics.

Special Thanks to Mark Page.

Home -- Sitemap

Copyright © 2008-09 RCAirplaneDesign