NITRO POWERED PunJet!

So I had a Cox 049 Skymaster laying around from a control line plane I built a while ago. But honestly, control line is kind of boring... A nitro powered mighty mini sounded way cooler!

The nice thing about having the cox engine as a pusher instead of a tractor is that all of the oil from the exhaust just gets spat out behind the plane, instead of all over the plane!

I'm building it out of depron as it will get some fuel on it. You can also see I modified the vertical stab's so that I won't smash through them when starting the engine.

I also modified the fuselage as I wanted to get the engine as far forward as I can (it's super heavy)

Ok, ok... fast forward to the completed thing. 

Nice, eh?

Depron is lighter than foamboard but it's also a lot less rigid. I know a carbon spar would have been ideal but honestly, I didn't want to wait for it to arrive and these bamboo struts don't cause too much drag anyway. 

Even though the ESC only has to provide power for the servos, it still gets bloody hot for some reason. So I made this vent hole on the bottom.

Now I don't really have any throtle control on the Cox engine, only a mixture control. So I just lean it until the RPM goes as high as possible, then make it slightly more rich and just fly like that. I would have flown full throttle if it was electric too, so it really doesn't matter. Each flight lasts about three minutes and at the end I just glide it to a landing.

I have a 3cell 500mah up front and a pad lock to balance the thing. It's a pig! However it flies great! The engine is actually really powerful and the torque roll is barely noticable. It's quite fast too!

Excuse the military uniform, just some school CCF stuff...

If you're planning on making one of these, it is SUPER important that you cover the bottom, bevelled edges of the duct tape hinges with a thin layer of hot glue, as shown in FliteTest's build video. I skipped this step and noticed that the hinges near the control horn were becoming very loose and sloppy (which made the thing fly loose and sloppy). The problem is that fuel will make duct tape peel off slightly. I tried doing that afterwards but hot glue wouldn't stick to depron soaked in oil...

I would also make the bottom vertical stab's a bit less tall, as harder landings would rip the rear part of the wing from the fuselage (that motor is heavy).

Also remember to fasten the propeller so that it is horizontal at the start of a compression. That way it will remain horizontal when the engine dies. 

The best thing about this plane is that you can fly for hours without stop. Just refuel and go, the battery for the receiver and the servos lasts for hours, so you don't have to wait for recharging at the field. I totally recommend building one of these, it's super fun!