RunRyder - OK, serious Ratio talk for an 80 XL

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Miniature Aircraft Nitro/Gas Helicopters > OK, serious Ratio talk for an 80 XL

spincycl
Veteran
Location: Marietta, GA

I gotta SE that needs a new motor, darn, and all they had at the hobby shop was a YS80, oh the humanity!

I have always liked a low ratio : 9:1 for a 61 WC, and the governor seems to like the whole setup. (Fury uses 9.3:1 for a 61)

But, with the 80, hmmm, I know the 8.45:1 (93T/11T), is the accepted best ratio. But, IS that the best for moderate 3D, FF etc...?

Some like running slightly higher than 8.45 (on other heli's with that choice.)

9:1 (10/90) is a little high ---- probally will cause heat problems.
8.1 (11/90) is way too low
8.45 (11/93) is the accepted norm
8.63 (11/95) is another choice

PLease advise......

03-25-2002 Over year old.

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Chopper
Key Veteran
Location: Stow,Oh- oops, I mean St Louis, nope Stow again

It seems that you have a handle on the gear ratios already. What is best is what works best for you.

03-25-2002 Over year old.

spincycl
Veteran
Location: Marietta, GA

I saw it.

Yep, your fly'in-flag was rock'in the sky.

That is interesting that a high ratio can cause lean spots. I still am a little fuzzy on what exactly make a good/bad ratio. I can rely on the fact that 8.45 works; a lot of guys like that ratio for 3D.

Thanks, and Bham was Awesome -!

PS. What kind of pitch are you able to pull? (blade length too)

03-25-2002 Over year old.

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steve9534
Key Veteran
Location: yakima, wa.

Gear ratios

I just got a YS 80 and put it in an X-cell with a 9:1 ratio and 710mm blades. It ran/runs perfect right out of the box at about 1600 RPM head speed, and I absolutely haven't been able to bog it. I'll get a momentary drop in head speed when I start a funnel, if I really crank in the cyclic, but it picks right up again. Maybe a lower ratio would give me a little more speed, but it works so good as is, that I'm not going to bother. Some of this depends on the blades and head speed one prefers. I generally run a little lower head speed than most, but with the 710's, the tip speed of the rotor blades is very close to 680's running at 1750 RPM. The motor RPM and the load on the motor is very similar as well. Hope this helps. Steve.

03-26-2002 Over year old.

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Miniature Aircraft Nitro/Gas Helicopters > OK, serious Ratio talk for an 80 XL

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