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Vertical Stall

Old 09-20-2008, 01:30 PM
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sctstone
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Default Vertical Stall

Just wondering if someone can give me some possible reasons as to why my os91fx suddenly wants to stall in a vertical climb? Its has run vertical in the past but the other day it started stalling out when held or flown vertically. Like I said, it has run beautifully prior with no changes to the setup.
Old 09-20-2008, 01:51 PM
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Knight_74
 
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Default RE: Vertical Stall

It sounds to me like you need to richen the needle setting.
Old 09-20-2008, 02:56 PM
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gjesion
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Default RE: Vertical Stall

Check the clunk. It may have moved to the front of the tank and is stuck there. This has happened to me a few times.

Regards,
Jery
Old 09-20-2008, 03:11 PM
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RCVFR
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Default RE: Vertical Stall

If it has been tuned for hot, humid conditions, and you are now running in cooler, dryer air, it needs to be richened up.

BTW, engines don't "stall". The wing stalls. Engines may burp, belch, gasp or just plain quit, but they don't stall.
Old 09-20-2008, 03:20 PM
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gjesion
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Default RE: Vertical Stall

From Dictionary.com definitions 9 and 10 for the word stall.

"9. an instance or the condition of causing an engine, or a vehicle powered by an engine, to stop, esp. by supplying it with a poor fuel mixture or by overloading it.
10. Aeronautics. an instance or the condition of causing an airplane to fly at an angle of attack greater than the angle of maximum lift, causing loss of control and a downward spin. Compare critical angle (def. 2)."

Regards,
Jerry
Old 09-20-2008, 11:20 PM
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RCVFR
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Default RE: Vertical Stall

Thanks. We're talking airplanes, here.
Old 09-21-2008, 09:18 AM
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Default RE: Vertical Stall

I'm the guy that always said, I never twist my needles after I have my engine in proper tune!! Watching needle twisters just makes me crazy!! Then I moved here, my engines were all in tune for hot weather but as it started to cool off I started getting dead sticks, first in my YS engines?? Then in all my engines. Well, going from 100+ all the way down into the 30 does cause some changes. When the weather went from the 100s down into the 70s I had to start fattening up my engines. They all needed 4 turns out from fall through winter then I had to start leaning again come spring. It's almost that time of year again here, at least now it's not A big surprise. Good luck.
Old 09-21-2008, 10:01 AM
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carrellh
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Default RE: Vertical Stall

ORIGINAL: Jim Dines
Thanks. We're talking airplanes, here.
The original poster wrote that his engine stalled. Defiition 9 seems to fit. Engine stalling due to a tuning or fuel supply issue.
Old 09-22-2008, 10:30 PM
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BillyGoat
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Default RE: Vertical Stall

Also check to make sure your pick up line isn't too long. Had this happen where the clunk was touching the back of the tank restricting fuel to the engine.

Ditto Jim Dines. When on the subject of planes only definition 10 applies. In other words, wings stall.... engines quit. When I saw the thread topic I thought this was about aerodynamics.
Old 09-23-2008, 10:33 AM
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spiral_72
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Default RE: Vertical Stall

Whatever the terminology it boils down to your engine is not producing enough thrust to pull the plane vertical. The easiest solution is to check your tuning.

Also, did you change props to a different size or manufacturer?
Does the model weigh more because you installed a larger battery or.....?
Are you using the same fuel or is it old/moisture?
As already mentioned, the cooler weather will make a difference in tuning and therefore power of the engine. As also mentioned there are fuel problems that can contribute to loss of power. Also, needles have vibrated out of adjustment, clunks move and stick forward in the tank.

Give your plane/engine a good check.


I had a fairly recent battle with an engine. The plane flew ok and had power, but when I finally got it nailed down I was rewarded with a "hammer the throttle and unlimited vertical". The plane shouldn't do it with the combination, but she sure proved me wrong! Sorry, got a little excited there.

Good luck
Old 09-26-2008, 05:12 PM
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sctstone
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Default RE: Vertical Stall

Thanks for the insight. It was definately the cooler weather that was causing the engine to "quit" I guess. Anyway, upon richening the mixture the engine ran fine at a vertical attitude. And yes, I meant the engine was quitting when the plane was in straight vertical climb, nothing to do with not enough thrust to sustain the climb, shes got plenty for that. Thanks guys.

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