Guys, I might cut my losses and just get a DL 50 for my plane.

The plane in question is a 28% EDGE 540. It's wing span is 76" and weight is around 12.5-13lb. I have been using an SPE 40cc but I've got some problems with it and might just use it elsewhere once it's fixed.

So, the question is, would the DL 50 be to much engine for this airframe. The weight of the SPE with Ignition and Muffler is 53 oz (3.3lb's)

The weight of a DL is 54.5oz's (3.4lb's) so that wont really be a problem.

I've already glassed the firewall and have good strength but is the DL going to be over the top and I'll be in danger of ripping the wings off

Hey, there is always throttle control

What do ya all think?

Go for it. Sounds like you have the main issues ( fire wall, throttle management )addressed. Recheck CG after engine swap.

I've got a Great Planes 27% Edge 540 ARF with a DL 50 in it. I forget the span, but the plane comes in at around 15 lbs. A 50cc was never recommended for that plane, but it flies great (okay, it's a bullet!). Sounds like your plane is even a little bigger, so performance-wise, should be okay. It would be up to you though to fly with prudent throttle mangement and strengthen the airframe as necessary.

Yea well, at 12.5lb's this is quite a light airframe which is why I'm a little worried I guess.

I might just go for it though

Should I have asked this in the engine forum?

Alex B,
You don't tell us where you live! The power requirements are quite different, depending on where you live.
When I use to live in New Jersey the good .61 engine would be OK on Goldberg Bucker Joungman, but now I live in Colorado Springs with flying field at 7,000 above see level and same airplane I would not fly with nothing less than 1.2 engine.
The bigger engine is fine if you use throtle management. You don't need to fly at full throtle, but it is nice to have it, if you need it.
Zee

I'm at Sea level.

The reason I ask is I need an engine for this plane but plan to put it into something bigger when finances permit.

I want to fly this plane in the mean time. When I get my 40cc gasser fixed I'll put it back in this plane.

So, I'll be using the DL50 as a stop gap

Go for it! I have a 27% GP Cap that weighs 13lbs with the DL-50. Flies like a damn foamy

Edit: I should add, on a light air frame it pays to take some precautions. Pin the firewall if it isnt already done, and always remember your throttle management!

So long as you've got enough prop-clearance I'd say go for it. There's no such thing as "too much power" -- so long as your throttle servo is still working.

You will be very well with that engine.