FredE 2X
 

http://www.stevensaero.com . Fred E 2X, I will be building this plane but think I would like to use a 4stroke around 40/52 size, any input appreciated. I`ve seen video of the smaller FredEs flown on glow but not the big one, so it seems plausible

Yeah those StevensAero designs have a lot of appeal. I don't doubt it could be done... Too bad there isn't a profile view in the instructions. I remember looking over the pdf of the manual with the same idea of converting it for my Saito 40 but decided the price of the kit was too high given the changes I would have made like moving the firewall back, maybe adding ailerons etc. The 10oz recommended battery appears to be behind the center of gravity, and in your case the receiver battery will be a fraction of that so balancing it could get interesting having doubled the weight of the powerplant if you use a 52.

I can't find the ad for it, but it sounds like the span will be around 54 inch; although it must have a very wide chord and thick airfoil, I would still go with the Saito 40a. I think a 52 FS is more power and weight than you would want. I'm basing that on an LT-40, about 4 lbs and a 63 inch span, that had terrific performance on a Saito 40a. Also, the Big Lazy Bee, which flew on a .25. Also, in the video above it looks like a very slow flyer.

What is this plane supposed to weigh?

Jim

wght electric is 4.5 lbs, motor mount and some structure may need beefing up but with 1050 sq inch wing area that won`t be a problem. A 32 brushless is the suggested electric powerplant, I was thinking of my OS40FS presurpass or a nice Saito 40

After watching that video I think I'd go with the old OS 40 FS. Also, I can't figure out how that thing turns! No ailerons, no dihedral, wing tips built flat with the bottom of the wing...where does the roll coupling come from?

A four stroke will sound great whichever one you choose. Looks like fun.

Jim

Buzzard Bait; I'd describe it as the pendulum effect from the short wing with it's high placement that does the trick. I wonder how much of that you'd lose eliminating the heavier battery used in the electric version, probably not enough to matter too much.

I would probebly go the other direction and error on the side of power! So let look at weigh vs HP of just the power system.
FA-40 is 300g
FA-56 is 410g
FA-62a is 420g <--- I like this one. It is closest to the HP of the electric motor.

fule - 100 - 200g
servo - 25 - 50g

So your total budget for wight with ht 62a is 670g

The E-Flight motor they recomend is:
Motor - 200g
ESC - 50g
battery - 300g

The CG will probably need to be modified by moving the engine back some. But I say go BIG! That plane seem to want a lot of static trust and you will want that bigger prop.