Engine Power required to lift the Helicopter?

[bhaazee]

I want to design a RC helicopter powered by a gas engine. The total mass to be lifted by the helicopter is 25 to 30 Kg. What is the engine power or engine size (in cc) required to lift the helicopter? Can someone please provide me some calculation?

Regards

 

[spggodd]

It would be useful to know the gear ratio involved in going from the engine to the blades.
However once you know this and the power the following formula should help.

Force required to lift = MA = 30*9.81 = 294.3 N

1. Calculate Area of Blades A = Pi*r^2 (ft^2)
2. Calculate Power Loading PL = Power/A
3. Calculate Thrust Loading TL = 8.6859*PL^(-0.3107)
4. Lift = TL * Power

Be aware that 10 - 15% of the power will be used by the tail rotor.

Hope this is useful and gives you a rough idea.
Steve

 

[bhaazee]

Thnx for the formulae. I have been going through the aerodynamic principles of helis. The relaions are quiet complicated to approximate the values and to find the power required.

Regards