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OK! give us some feedback when you find out. Just for the heck of it, how was the torque at Flight idle and above?

Could not get to flight idle - almost any throttle movement in that direction caused even more blade angle, and reduced rpm

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QUOTE (Dan)

You missed that they switch out the prop with a known good prop, that would (normally) eliminate the prop and bring it down to engine, rigging or cosmic rays.

QUOTE (pjvr99)

NO!!! We still don't know what's wrong with the prop. So the search, trial

and error continues until we do know.

brothers of T56, my English language is below 720⁰c. Yet I am unable to differentiate between (lay & lie). :o

Nevertheless, my understanding is: Till the investigation reveals the actual cause of the prop defect we may guess which component at fault on the prop based on how system works. Am I correct......?

QUOTE (NATOPS 1)

The increase in speed would directly affect the pressure output of the main and standby pump. The standby (twice as much voulme) may be suppling pressure when not needed...normally only provides "extra" pressure/volume to get faster response. If it thinks the system wants more due to a bad check valve it may be driving the blade angle without any input other than speed.

Make sense to me.

Anything more prop guys?

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So you changed the prop... Does that mean just the prop or the prop, valve housing and pump housing as an assembly?

Understand the engine is what you are checking and it works fine. ONE DOWN!!!

So the Prop is defined in this instance as just the propeller and dome?

Same valve housing?

Same pump housing?

Still very strange!!!

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So you changed the prop... Does that mean just the prop or the prop, valve housing and pump housing as an assembly?

Understand the engine is what you are checking and it works fine. ONE DOWN!!!

So the Prop is defined in this instance as just the propeller and dome?

Same valve housing?

Same pump housing?

Still very strange!!!

For prop read complete assembly. The prop guys replaced the valve housing in shop, and

installed the assembly on another engine. We will try it on Saturday

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Off topic: What did the Saudi's do with the 6 E models they were trying to sell?

Thanks

Bob

Actually, the Turkish Air Force has bought five of them, as is!!! They’re currently being put back into a “flyable” condition…

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For info, the problem is definitely NOT on the engine. We ran it with another prop without

any hassles. The problem prop received a valve housing removed from a tear-down, and

quite happily made the seal break-in run for another engine this morning. Tomorrow we'll do

a full run.

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Gotta love installing bad parts... please let us know what the issue is when you find out... Strang to have this once much less several times.... bad valve housings that cause blade angle increase when at high speed. go figure..........

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Changed out valve housing, pitchlock regulator, and low pitch stop. Also removed all

cannon plugs to remove electronic influence - no good! Stays the same .....

Two “Valve Housing†having unusual identical defect … !!!!

No comment.

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