super cub
 

hello, i need help i have aquired a super cub from a friend of a friend lol and i need help with a few things first i dont know who makes it but it has an 86 inch ws and is fully detailed with instruments, skylight and cowl with dummy engines. my question is will a 91 4 stroke fly it? and the next question is how do i find the thrust line to mount the engine? the firewall has so many holes in it i cant find the original ones to use they have been either epoxied over or just left open. and the final question is where the heck do i find the cg for it. i need help because there was no paperwork with it and it was freeeee>

please help
thanks aerodan

super cub
 

Okay. First, a 91 4 stroke should fly it fine. May even be over powered. (I have an 81" Cub that flys well with a 52 4 stroke.)

Did you get the cowl with the plane? Put the cowl on, then using a pencil lined up in the center of the front cowl opening, make a mark on the firewall. Should come out close. (Or make diagonal lines between all those 'opposite' holes on the firewall. Where most of them cross should be the center.)

Start with a CG that's 25% of the wing chord where it joins the fuse. ie. If the chord is 12", place the CG 3" back from the leading edge (on the bottom of the wing).

I'm sure others will have different opinions, or better ways of tackling your problems.

Good luck,
Dennis-

super cub
 

sound good thank you for your time i will give it a try.

super cub
 

Are you planning to fly off wheels or floats? Is it a clipped wing or full? Your engine size will depend on you alttitude and the above combinations - my suggestion would be to try it and see - just be careful not to push it to steep for the maiden and see how it performs at a good hieght - my guess is it will fly it but it won't be a power house , but then cubs are at their best when flown scale. Your CG should be right on the main spar of the wing - I would balance at the rear of the spar to start. As far as the engine mount judge by other holes depending on your motor mount holes (it is difficult without the plans) you may want to sek a more experienced builder out near you who can advise you on this but in my experience if it's close it will work. good luck and hope this helps.