Calculation basics for Building RC Aircraft(without flaps)

Calculation basics for Building RC Aircraft(without flaps)

Please do post your queries & experiences with other ratios than mentioned so that we can also learn new things. Please do share your views.

With the following steps one can build his/her own small scale RC plane.

Step 1: Select an appropriate airfoil for the wing and its chord length based on the requirement.

Step 2: Calculate wingspan based on the aspect ratio with respect to the chord length. It is usually        5-6:1 ratio with chord length. If you are building a high winger plane then wing span doesnt include the width of the fuselage. For low winger(& diherdral) and mid winger it will even include the width of the fuselage.

             For general aircraft the aspect ration varies from 5-6. For gliders it can go 6-7.5. Extreme high aspect ratio can also be harmful if not well designed.

In a small scale plane. One spar is present at maximum thickness of the airfoil & the other spar is placed at 1/3 of the chord length from the leading edge. The CG of the plane shall lie in between these 2 spars.

Aileron Area = 10%-12% of the Wing Area(in case of a payload lifting aircraft)
Width of the Aileron = 20%-25% the chord length

In case of stunt planes: Aileron width = 20%-25% the chord length
                                      Aileron length = wing span on each side of the fuselage

Step 3: Calculate the length of the fuselage. It is usually 70%-75% of the wing span.

Step 4: Nose Length is the distance from the tip of the nose to the leading edge of the wing. The distance ranges from 15%-20% of the wingspan.

Step 5 : Calculate the Area of horizontal Stabilizer. It is usually 20%-25% of the Wing Area. Elevator area is equal to 25% of the horizontal stabilizer area. Elevator width= Aileron Width

Step 6: Vertical stabilizer area is 20-25% of horizontal stabilizer area or it can also be taken as 10% of wing area. Rudder area is 25% of the Vertical Stabilizer Area. Rudder width= Aileron Width

Typical Calculations

If you require any another assistance or if you have different calculation ratios got by experience please do share in the comments section we will be pleased to know and learn.