YS 91 Heli Motor on Airplane????
04-12-2008, 05:57 PM
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YS 91 Heli Motor on Airplane????
I was wondering what the deal is with using heli motors on airplanes? I have seen a few people doing it to make some real speed demon planes. The YS91 SR is rated to turn up to 15k RPM. I know nothing about gas helicopters drivetrain systems, but I was wondering how these people are able to affix a propeller to these engines? I have a keecat 65 and am very limited on the diameter prop I can run. An 11x10 is about the biggest load I can put on. It seems that these heli engines are much more powerful somehow than the airplane motors. more compression? different timing? And if they are able to spin these props are those RPMs....why don't they market them as an airplane engine as well? Anyways...long story short, can someone fill me in on the pro's and con's of heli engines on airplane? Thanks 
04-13-2008, 03:11 AM
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RE: YS 91 Heli Motor on Airplane????
This have been up before and I can`t remember that there is any significant difference between an engine that is offered both in heli and areoplane versions other than the carb and the cooling head. There have been some guys here who have converted heli engines for use on planes, but I really don`t think they get more power and speed out of it than the same size/type aeroplane engine. The main goal was to find a use for a heli engine just lying around unused.
You only need to find a muffler that fits and a prop hub that fits on your crankshaft and give it a go, should be great[8D] The carb is fine on a plane too, I use the carb from a OS 50 heli engine on my OS 91 FX and it works fantastic.
Also OS 91 and ASP 91 and propably others too are rated at 15K or more
You only need to find a muffler that fits and a prop hub that fits on your crankshaft and give it a go, should be great[8D] The carb is fine on a plane too, I use the carb from a OS 50 heli engine on my OS 91 FX and it works fantastic.
Also OS 91 and ASP 91 and propably others too are rated at 15K or more
04-14-2008, 11:15 AM
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RE: YS 91 Heli Motor on Airplane????
The 2 biggest drawbacks to useing a heli engine on a plane are.
1. The engine will tend to run to cool with the heli head
2. The crankshaft is to short, but can be used with a pass thru prop nut.
3. Also as was mentioned the prop hub itself.
1. The engine will tend to run to cool with the heli head
2. The crankshaft is to short, but can be used with a pass thru prop nut.
3. Also as was mentioned the prop hub itself.
04-14-2008, 02:56 PM
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RE: YS 91 Heli Motor on Airplane????
That rating is for a helicopter drive system, you would use the same props and rpm ranges with a heli engine and a prop that you would with a plank engine with a prop. IE you might get it to turn that fast but it would be a very small prop.
