graupner piper j-3 engine
 

asking for my friend
He has ordered piper, wingspan 71". The recommended engine is 7,5 cc but he is thinking to mount an 10 cc engine on it as he owns one already.
What do you guys think, will it be a problem?
I know it the plane going to be heavier and faster. But does it affect flying characteristics? Does the engine fit into cowl etc??

Thanks
Crow

graupner piper j-3 engine
 

Would that 10cc (.61) engine be a two cycle engine? If it is then it will be a bit much for that plane. A 10cc four cycle will also be a bit much. I have the Hanger 9 80" Cub and it flies great on a .52 4 cycle and a friend has a .50 4 cycle in his.

The engine will be a bit heavy, but most Cubs need the nose weight as they have long tails that need to be balanced. I will geuss that it will fit inverted, but a large 2 cycle muffler will cause more problems -- assuming the engine is a 2C...

Having the 10cc will make it a bit heavier, but I don't think a Cub will be too bothered as it has a lot of wing. It also may not fly that much faster... If you prop it right you can keep the speed down and increase the thrust. Also, a Cub is not a sleek machine so it will only go so fast before the drag exceeds the extra power...

graupner piper j-3 engine
 

thanks for your input

Iwas just thinkin, i have 10cm longer wing in my cub and manual shows two stroke engine up to 10ccm. seem weird to me, 10 cm shorter wing and max engine you can use is 7,5cc??!!

Crow

graupner piper j-3 engine
 

use 8,5 cc 4-stroke saito, o.s. or asp
We used 8,5 in Great planes 2m cup without any problems