Hi all I am thinking seriously about trying something, I have opportunity to get a Great Planes Ultimate Bipe E-Performance EP 3D ARF ( http://www3.towerhobbies.com/cgi-bin...5&I=LXMUX3&P=K ) and I am thinking of converting to nitro with an OS .26 4 stroke. Just wondering if anyone might have done this or think it it will work??

Electric doesn't vibrate or have power pulses from the engine.

I think the airframe would fall apart in short order due to the power pulses and vibrations from the internal combustion engine. They aren't built to take the kinds of loads that a glow engine will put out.

Just my opinion.

If you are flying off of a hard surface you would be more likely to succeed since these planes have small wheels.
You would not get 3D performance with that .26.
Beef up selected areas such as the firewall if there even is one, tail connection points, the area where the fuel tank would sit, etc.
Use light weight radio components, etc.

It is a much bigger airplane but see: http://www.rcgroups.com/forums/showthread.php?t=893762
for a conversion of the Hangar 9 Beaver to a .25 two cycle.

Can it be done, yes.
Will it work, not well.
In order to do so the structure of the airplane must be beefed up to take the vibration and pulses produced by an IC engine that an electric does not produce. The weight of these modifications are going to increase the wing loading and up the power requirements.
Now lets take a look at the engine vs., motor switch.
Now a common factor in motors is horsepower one horsepower is roughly 750 watts. The closest spec I can find is an OS .29 four stroke which is rated at a max of .5 horsepower or 375 watts. The electric motor suggested for the airplane is 330 watts continues and 390 watts peak.
Your .26 is going to produce less power than the .29 and the electric, require more weight added to the airframe so what do you gain, nothing other than the sound.
You would be far better off using a 450 to 500 watt motor and a bigger battery if what you seek is better performance.

Well, I am not really after more power per say, i am just looking at doing something a little different, kill the boredom, give me something to do etc. I am not real knowledgeable about electric, and was looking to make a nitro out of this. But from popular opinion it looks like my idea isnt going work

I say go for it! As mentioned, you should beef up the week points a little. There was a thread a while back where a guy put a small four stroke engine in a GP Super Sportster EP with great results. Sounds like a fun project!

-Johnny-

Not that it would not work per say, just that it would not work well with a .26 4 stroke, your power would be very minimal given the weight gain.
If I were to do it I would be thinking along the lines of a OS FS 40s with a three blade 9X7 prop. I do not have a knowledge of the airplane itself but looked up the specs. from your link, given that it has an AUW of 2 lbs when electric I would hazard a guess it would be a lot heavier after your modifications an more power would be in order. However if you looked at the weight of the original components including the battery and substituted the weight of the glow components it would give you an idea of what you could do.
If you haven't tried an electric powered airplane they are not all that hard to understand and can be fun. I have a re-motored original version sig EP42 I keep in the back seat of the car and it is neat to have a plane I can just drag out turn on and fly when I want to. All I need is the plane my radio and a li-pol charger and I am all set to fly, no field box and fuel to lug around. But I still like my glow planes and most of my planes are glow or gas but I do have a few electrics.
Hey if you want to try to mod it to glow just understand what you have to deal with and have at it.
This is just a hobby so have some fun!