Hello looking for information on engine to plane sizing,(weight to power) ratings for say a os fs 70II how much weight(plane) will it pull with authority

also looking into getting into gas powered, what is the conversion from a 120 4stroke to say a zenoah 20ei?

thanks
Big-Mo

Hi Big Mo, I dont know about weight and size ratios, but if you have a zenoha 20cc it will go in a seagul extra 1 20 size I have this set up and test flew it on sunday and it flew much better than I expected. This set up gives a very good SPORT performance. The total weight came out at 12lbs. I put a 3cell ignition battery in, 3cell is what they recommend . I managed to get hold of a 6,500 MAH which gives loads of running time and the bit extra weight just works out for the c of g. Hope this has been of some help. I love my little zen , they are a great little engine , not a lot of mess either. Happy flying . Regards Bill.

Big Mo, I think a 120 4 stroke is about 19cc but may give a bit more power than the20cc zen , but not sure on that Bill

I think the 70 four stroke will pull 6 lbs with authority.