pjvr99 Posted June 17, 2010 Author Share Posted June 17, 2010 So, we call it quit!!!......... NO!!! We still don't know what's wrong with the prop. So the search, trial and error continues until we do know Quote Link to comment Share on other sites More sharing options...
tusker Posted June 17, 2010 Share Posted June 17, 2010 OK! give us some feedback when you find out. Just for the heck of it, how was the torque at Flight idle and above? Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 17, 2010 Author Share Posted June 17, 2010 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 Quote Link to comment Share on other sites More sharing options...
tenten Posted June 17, 2010 Share Posted June 17, 2010 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). 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? Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted June 17, 2010 Share Posted June 17, 2010 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!!! Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 17, 2010 Author Share Posted June 17, 2010 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 Quote Link to comment Share on other sites More sharing options...
bobdaley Posted June 17, 2010 Share Posted June 17, 2010 Off topic: What did the Saudi's do with the 6 E models they were trying to sell? Thanks Bob Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 17, 2010 Author Share Posted June 17, 2010 Off topic: What did the Saudi's do with the 6 E models they were trying to sell? Thanks Bob AFAIK they're still at Al-Kharj Quote Link to comment Share on other sites More sharing options...
bobdaley Posted June 17, 2010 Share Posted June 17, 2010 Thanks Bob Quote Link to comment Share on other sites More sharing options...
Dan Wilson Posted June 17, 2010 Share Posted June 17, 2010 : always the possibility of a malfunctioning fuel control Removed from equation by installing a known good prop Okay, this was the thing throwing me. Was a good prop hung or a good FCU? Quote Link to comment Share on other sites More sharing options...
MARS Posted June 18, 2010 Share Posted June 18, 2010 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… Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 18, 2010 Author Share Posted June 18, 2010 Okay, this was the thing throwing me. Was a good prop hung or a good FCU? Didn't do anything to the engine - only removed prop assembly, and fitted a known good one Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 22, 2010 Author Share Posted June 22, 2010 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. Quote Link to comment Share on other sites More sharing options...
Parrot Posted June 23, 2010 Share Posted June 23, 2010 Sounds like you need to send the prop to the shop and have the pump hsg and dome resealed. Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted June 23, 2010 Author Share Posted June 23, 2010 Did a full run this morning - total success!! Valve housing is the culprit. There's been a few others recently doing the same thing, so now we need to isolate the source of the problem Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted June 23, 2010 Share Posted June 23, 2010 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.......... Quote Link to comment Share on other sites More sharing options...
tenten Posted June 23, 2010 Share Posted June 23, 2010 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. Quote Link to comment Share on other sites More sharing options...
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