Daniel-EL

My Feedback: (9)

I am building a Ziroli DC-3 which I will power with two Enya VT-240's. Is there a practical way to reverse one of the VT-240's so that I can have counter-rotating props?

earlwb

I don't think that anyone has wanted to reverse a Enya VT-240 engine before. Enya didn't normally made reverse rotation camshafts for their four stroke engines either.
But my first inclination is to say no, that you can't do it. But then maybe there is a way though. I have not tried it but one can reposition the cams on the Enya four stroke engines to achieve reverse running. So it is theoretically possible that one could do it on the VT-240 too. I have not tried it though so I cannot say that it works.
Here is a link to information on how to do with with some Enya single cylinder four stroke engines.
http://www.modelrectifier.com/resour...enyarevrot.pdf

Daniel-EL

My Feedback: (9)

Thanks. I thought I'd seen that page before, but completely lost track. Since the VT-240 is essentially 2- 1.20's stuck together, I'll try the instructions for reversing the 1.20 on each bank. Also, I think there is an Australian guy that reversed a VT-240 once and wrote about it here, but it was long ago and I lost track of him too.

706jim

While this won't help you (I don't know how to reverse the 240) I can tell you that it is an interesting thing to do. i built a twin engined sport monoplane powered with two OS 40's; one with the reverse cam that allows two counter rotating engines. P factor is totally eliminated allowing the aircraft to turn identically in either prt or starboard turns.

1QwkSport2.5r

Reversing Enya 4-strokes is possible though I don't know where to set the cam timing. I'm pretty sure it's been covered in the Club Enya thread.

earlwb

I posted a link to the documentation for how to reverse a single cylinder Enya engine above in post #2. The method may work for the VT-240 too.

1QwkSport2.5r

I missed that Earl, sorry.

earlwb

Hey, no problem, I figured you did.
It is pretty neat, something I hadn't really thought about doing myself. It is worth saving the file for future reference.
The file might stay out on the internet for years or disappear the next day.


Of course I am totally impressed with the OP using two VT-240 engines in a twin engine airplane. Now that is going to be impressive and something to see.

Daniel-EL

My Feedback: (9)

Roger Young did this set-up in the early '90's. You can see (and hear) his VT-240 powered C-47 in the early Top Gun tapes. It was beautiful, but unfortunately Roger died right after the 3rd (I think) Top Gun and we never saw that C-47 again. The sound sent a thrill up my leg and I vowed to have one someday. I don't think he had counter-rotating props.

gerryndennis

Hi Daniel,

That's probably because the full size doesn't have counter rotating props either.

Dave H