As the title suggests, I inherited a piper cub from someone whose dad had passed away and was in the final stages of building it. He has an OS .40 FP set aside for it with a Macs pipe, and I was wondering if this thing will be big enough to fly it. I don't mind flying it scale, but I don't want to be grounded when the wind is 10 mph. If it is too small, I may consider converting it to Electric before any glow fuel has hit the covering.
Thanks,
Curtis
P.S. I test fired it in my hand and the engine seems to have good compression and runs ok for a short burst.

You ran the engine in your hand? If so that is nuts.....
You don't mention the wing span or weight of the airplane

Yeah, just a squirt of fuel in the carb to see if it would pop. The WS is 76" and I guess will weigh between 7-8.5 lbs.
C

I have an 8# J3-Cub with a 71" wingspan powered by an OS46FX engine driving a 12 X 4 APC prop. I think a good 40 will be OK. Suggest you research the J3-Cub here to learn their differenc. They love to snap roll on take off. You could total it on your first takeoff. You cannot fly them without frequent rudder use.

I have an unfinished Goldberg Cub. I was going to put a magnum 70 4 stroke in it.

Curtis, Clip the wing (2 bays) and put an OS 70 Surpass on it. You will have one of the most amazing airplanes you have ever flown!

Very true if you can find a good OS .70FS. I had one in mine with the full size wing and it was a good combo. Clipping that wing turns a Cub into a nice little stunt plane.

Yeah, I think I would have if the wing wasn't already built and covered. All of the main structures are built and covered, It's almost like it is in ARF condition right now. I need to mount the tail surfaces and finish up a little on the landing gear and such. I would like to put a 4S into it, but I am not sure how much I want to invest in it right now. I really liked how I converted my Giles over to Electric, I would use the same motor and ESC and borrow batteries back and forth, so I am considering that if the FP will be too underpowered. I am not concerned about the short coupling, as this is not my first short coupled taildragger in my fleet, just my first cub. Thanks for the advice. This FP, I believe is a bushed engine (as it has a very narrow front crankshaft journal) and it is a 40, so both are going against me, but I bet it would be quite scale like.
Curtis

I built a CG Cub 10 years ago and put an OS 40 FP on it. What a bad combo. Because the 40 is so light it took probably a pound of weight to balance the model. Notice the short nose. And the 40 couldnt pull the Cub thru a loop without diving first. Very sad. So, IMO youd be wasting your time putting a 40-46 2C on it.

After I flew mine only a few times with the 40 I upgraded to a Magnum 91 RFS. That took the Cub to a whole new level of fun. The Cub would knife edge with the 91 and a MS 14*6 or throttle back to 1/4 and putt around all scale like.

Cheers.

That is the info I was looking for. I hadn't even thought about the weight and balance issue. Thanks for the insight.
Curtis

Not to be getting down on you are flaming or anything like that.
This is a beginners forum and other beginners may read this thread.
It is NOT ok to hold a running glow engine in your hands. It is very dangerous and could result in severe injury.
Please don't do it.

True,
I don't want to condone that kind of behavior either, I should have left it out of my post and shouldn't have done it myself.
C

My CG Cub is built with a clipped wing. Had a ST .40 on it and it flew it scale like and did pull it around pretty good. Like Minnflyer said , a .70 four stroke make the plane much more fun . Had a Saitop .72 on it and this seemed the best combo.

a .40 will fly it, I have a GP J-3 with a .46 LA in it and it will take off at 1/2 throttle and cruise around at 1/4 throttle. I'm using a MAS 11x5 prop on it and had to add about 10oz of lead to the firewall to get the CG right.