airraptor

My Feedback: (66)

I am on a quest to get a dominator 1500 in upper 150 range. i am lookig for a engine that can spin a 18x18 - 20x20 prop in the 9,500 rpm range. I do remember in one of the model airplane news mags on the last page that a guy in canada made a 50-75cc wankle rotary engine that made about 10hp at 10,000 rpm and 18-19hp at 20,000 rpm. Do either one of you guys know where i could get a light weight rotary like this one or have contact info on this guy. I had the info saved on computer but my hard drive crapped out and couldnt get the info off of it.

Thanks guys

Tired Old Man

My Feedback: (1)

Only ones I knew about came out of England and it's been sometime since I paid any attention to them. My last encounter with them was relative to UAV engine designs and I haven't kept up with them. Therefore I can't remember their name....

gkamysz

My Feedback: (19)

I have to guess it's this you're thinking of.

http://www.modelairplanenews.com/blo...plane-secrets/

pe reivers

Hey guy, wake up!
To spin a decent 18x8 prop at 20,000 rpm you have a tip speed of 1.4 mach and would need about 40+ hp !!!!!!!!
A 20x20 in the 9500 region would still need 15+ hp and be operating at tip speed of mach 0.74, which is doable.
Things do not work the way you seem to think they do. So what about redefining your requirements while being awake and not dreaming. Pinch your arm skin twice to make sure please?
Am I over-reacting?


PS
Greg, answer to OP, not to you.

Antique

My Feedback: (4)

Our GT80 race twins turn a 19-18 about 11,500 on methanol...Would be almsot useless on a sport plane....And the fuel cost would be outta sight
Don't know if a Dominator 1500 would stay together at that speed anyway....Reinforce it well....
Our stock GT80s run about 140+ mph on 26 lb formula one planes, if you could get a GT80 on a Dominator it might work, but you don't need 20,000 rpm, the gas 80s turn 9000 in the air...I thihnk the props are about 19-16.....Or thereabouts....
The 80s are so smooth running you might get away with running one on a Dominator, start by scrapping the stock mufflers, get a RC EXL ignition to save weight...There's one on E bay, I bid $400...

spaceworm

Of topic, but I need to know, Antique, please. What are the mounting dimensions of your lightened G62 with ECDI? Thank you very much.

Sincerely, Richard

Antique

My Feedback: (4)

Square bolt pattern, 2 1/2 inches center to center, on a 3 inch square mount...

Tired Old Man

My Feedback: (1)

I only replied to the part of the question regarding the rotary. I wasn't, and won't, touch the part about RPM and power delivery.

Antique

My Feedback: (4)

Good call, 18 pitch @ 12,000 is about 200 mph....Last weekend in Texas at the race....

wyo69cowboy

My Feedback: (2)

Ralph, as you modify the 62's and 80's all the time, would you say a piston port design is as good(or better/worse) for high rpm power than reed or rotary valve motors? As you mentioned here, useless on a sport plane; I'm guessing because there is no low end power or "driveability". Just got me to thinking back on my old 440 Jet Ski days, where we ported those piston port cylinders and noticed a definite loss of low end/spitting back/"driveability...

Antique

My Feedback: (4)

Rotary is best, reed next...Piston porting is more of a compromise between torque and rpm...Zenoahs are ported for higher rpm power than most new engines used in torque rolling planes where they run at around 6000 rpm..

captinjohn

Antique, is Ashtabula on the circuit this year? Thanks Capt,n P.S. I miss that cute Snoopy Avitar !

Antique

My Feedback: (4)

Nope, Ashtabula is done...The CD said he would do it for 10 years....New race site is Hearne, Texas...

airraptor

My Feedback: (66)

Thanks TOM and Antique.

Pe reivers and the rest lol read my post no where did i say I wanted to spind those props at 20,000 rpm.

Yes that article is the one i am talking about. Thanks for looking that up for me. i didnt have time to call or look up the article on friday. Thanks

The GT80 is to heavy.
I might still go with a Moki 2.10 modded up so i can run 50% and spin a 16x15 prop around 9,300 or so. A gas engine would be cheaper to run in the long run though so that is why looking for a gas engine. The wankel in the article would be an easy install and easy to cowl in on the plane.

I have been looking at a DA85 or the ZDZ 90 also for this project.

gkamysz

My Feedback: (19)

If he's developing those engines, he's doing so privately. I've not been able to find reference to then anywhere else.

airraptor

My Feedback: (66)

yes no reference anywhere but i did find out where he worked and emailed him last year but nothing. I do hope he does come out with them soon. Wankels have always made more power than the piston engines of same size. If he can really get 5-6 hp out of the 20cc size will be a strong engine for sure.

I know Nitto makes some 20cc size wankels but they are not that strong in power and a bit expensive at around 2000 US dollars

speedracerntrixie

My Feedback: (29)

Part of the problem is that the Dominator is not really a fast airplane. If you were to cut a different wing that tapers in cord and thickness with a decent airfoil it would help alot. IMO your best bet would be to get a DLE 30 and send it in to Ralph for conversion to Meth. I would even ask him about the conversion while keeping spark ignition. An OPS Maxi 30cc on glow and tuned pipe setup would work well too if you can find one. You planning on flying this at your home field? It's a little on the small side.

Tired Old Man

My Feedback: (1)

If you had hoped to use a gas engine design to extract maximum power you would end up going full circle because the gas engine would have to be run on alcohol/methanol to achieve the elevated output. It's an unfortunate but true tradeoff.

A gas engine makes a lot of torque but doesn't make a comparable amount of RPM unless run on a different fuel. The larger planes easily carry the greater weight of an engine designed around the use of gasoline. Since gas engines run hotter they require more mass to handle thermal management. Torque is what is typically needed to fly larger and heavier aircraft at reasonable or scale speeds. Once the fuel changes from gas all that fuel reduction costs goes out the window.

airraptor

My Feedback: (66)

Speed, I will go with a smaller wing tapered and thinner airfoil. I could find faster planes but I like to take planes not designed to go real fast and make them fast. Like my .46size revolver with a OS 120AX. I wouldn't buy one of those engine because I already own a Moki 2.10 and a MDS 2.18 that I can add a pipe to. I will cowl in the engine I put on there. I won't buy a gas engine and convert to glow.

I have been learning from all threads that the 3W and zenoah engines are timed for higher rpm. I can and know how to mod most engines for more power. I like the idea of the wankel for power though.

Thanks all for helping. I wonder how fast someone has got one of these up to?