Throttle creep and return springs.

by Mike Hoare in General Tech Discussion 11 years ago

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Re: Throttle creep and return springs.

by Al C » 6 years ago

Al C

63 138 106

I understand the fail-safe logic of having the carbs go to wide open throttle rather than idle if the throttle control cable broke or dis connected.
That's how ours is set up for now.

But it's far from ideal, as ....assuming you prop ptich is set normally and you don't have an inflight adjustable prop....that would kick up RPM to 5800 ....well above max sustainable. Arguably cause engine damage and failure .... would be a scary situation to find oneself stuck at WOT, say, more than 15 minutes from nearest safe landing. Not as scary as dropping to idle I admitt , but scary.

In that situation I'd turn off one mag...at least drop RPM down maybe 100 or 150.

But ideally I'd like to find a way to have, in broken cable scenario, it drop to, say, somewhere between 5000 and 5400.
Any ideas how to kludge or engineer that?

Al

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Re: Throttle creep and return springs.

by Roger Lee » 6 years ago

Roger Lee

127 5.21k 4.79k

Most don't have their rpm up at 5800 WOT. Some do depending on the prop and aircraft. The big but here is you absolutely can fly at 5800 for those 15 minutes if you needed to without engine damage.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: Throttle creep and return springs.

by Charles Clayton » 6 years ago

Charles Clayton

5 30 43

Well, when I first bought my plane the previous owner had installed a "locking" throttle cable. There was a button that had to be pushed to advance or retard the throttle. Never had any creep. Unfortunately, this also locked out the passenger side(I have a Zenith 601 which has dual throttles). Since I was using the plane for lessons my instructor told me before my check ride I would have to get it changed because the DPE wouldn't go for that. I had it changed and even with the friction adjustment all the way it still creeps a bit but it's manageable.

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Re: Throttle creep and return springs.

by David HEAL » 6 years ago

David HEAL

23 189 422

On some standard friction-lock throttle cables you can unscrew the friction-locking mechanism and increase the packing to increase the friction-holding force -- I added a small round leather washer on my RV-12's standard throttle cable. Also, there are a number of different springs available to adjust the throttle-open tension at the carb. The McFarlane vernier/push-pull throttle cable appears to be the best but may not work in your dual throttle configuration.

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Re: Throttle creep and return springs.

by Eduardo Barros » 6 years ago

Eduardo Barros

4 5 2

Thanks

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Throttle creep and return springs.

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