Raptor 60 Motor

[schucb]

I am wondering if the 91 would be ok in my 60 Raptor? Can I just run it at 85% of full throttle or is that not recommended? I want to make the 60 a 90 size over the winter, so the 91 size motor would be used in the future. I am currently running 680 Mavrikk G4 blades. Do I need a longer tail to run the .
91? Will I need longer blades?

[Raven_darkcloud]

I am sticking an os 91 in my 60. the big thing is change the clutch to the 90. As for tail blades I use 105's on my 60 anyway. Consider some people are putting 90's in t600n's. Oh and change the gearing to get the hs you want.

[schucb]

I am sticking an os 91 in my 60. the big thing is change the clutch to the 90. As for tail blades I use 105's on my 60 anyway. Consider some people are putting 90's in t600n's. Oh and change the gearing to get the hs you want.

Thanks for the tips. I ended up buying an OS91 and a futaba governor to keep things under control.

Does anyone know of a site where I can do the gear/ headspeed calcs?

Will I need a metal center hub on my head?

[forjer]

Dang...you are a heli-whore aren't you. When I helped you dig out for that window the other weekend was I actually digging you a dungeon to stash all your heli stuff in? :cheers

If you know what RPM you want your engine to run at and a target head speed, you can take that RPM and divide it by the desired head speed to get the ratio. Then I'd guess you'll have to figure out what pinion / main gear ratios are available.

In the Raptor 50's, the engine's HP is rated at 17,000 RPM and a common recommended head speed is 2000 RPM which works out to the 8.5:1 gear ratio. This is reached with an 85T main gear / 10T pinion.

The 90's HP is rated at 15,000 RPM (is that right?). So if you're looking to run that in your 60 with the stock size blades / boom... then if your looking for an 1800 rpm head speed (not sure if this is what you want), then you're looking for an 8.333 (or slightly less governed) ratio. That would be something like a 100T main and a 12T pinion if those are available and actually fit in the R60. The stock 60 ratio is 9.3 I think.

Freaks...please correct me if I'm mis-informed as I'm still learning this stuff.

[Raven_darkcloud]

93t with 12t pinion = 7.75 for 1935 hs, 95t with 12t pinion = 7.91666 for 1894
93t with 11t pinion = 8.45 for 1775 hs
My shopping list consists of
pv0408 heavy duty clutch bell
pv0322 heavy duty clutch
pv0193 12 tooth pinion
pv0324 hd clutch liner
pv0351 oneway reinforcing ring
Just over 50 bucks to go 90 on the airframe (keep in mind I have the long boom) I got my os cspec used and already omi moded. (Thank you Terry) I will be running a carb smart on it.

[Raven_darkcloud]

Oh and stock main on the 60 is 93t.

[schucb]

Brian at Heliproz said a 91T with an 11 on the main would be what I would want to be at a gear ratio of 8.27 which sounds right.

[Raven_darkcloud]

Thats at about 1800 hs I looked at the manual for parts and tooth counts, Did not know you could get a 91 for the 60/90 as it only lists 93, 94, and 95t mains in the manual.