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What does it take to damage a turbine?

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What does it take to damage a turbine?

Old 10-28-2014, 08:31 AM
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essyou35
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Default What does it take to damage a turbine engine?

I am curious when a turbine should be checked out. Obviously if there is physical damage, noises or signs of rubbing it should go in. But what if there are not any signs but you have a mishap? I often see things and I wonder what type stress the turbine went through.

here are some cases I have seen and often wondered: (these did not necessarily happen to me)

A stall 5 feet up, jet pancakes to the ground, flex plates break.
Front gear collapses on landing, sucks up dirt or grass.
A 5 or 6 bounce landing where it bounces higher and higher until it stalls and lands flat, maybe breaking a flex plate.
A hard gear up landing
A light cartwheel where the wingtip hits and it goes up on the nose, then lands on the back.
A landing off the runway, gears break out.

I know turbines can rub internally on the compressor where you cant see it. Does anyone of a picture of what a rub looks like?

I mean how fragil are these things? I read a thread one of the manufacturers made it it mentioned things like bent exhaust cones, bent starters, bent turbine mounts. That just seems extreme to me! What about the invisible things you cant see?

I would hate to send my engine in everytime I break a flex plate but curious if that is what should be done.

Thanks!

Last edited by essyou35; 10-28-2014 at 08:38 AM.
Old 10-28-2014, 08:56 AM
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LGM Graphix
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If there is no visible damage and no vibration the next time you run it there's little to worry about. There is one moving part in there that can handle high g loads while spinning huge rpms. Ingesting fod is probably the worst problem in the scenarios you listed.
Old 10-28-2014, 09:33 AM
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FalconWings
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A stall 5 feet up, jet pancakes to the ground, flex plates break. Engine damage unlikely, components at risk.
Front gear collapses on landing, sucks up dirt or grass. Engine Damage unlikely, but it needs to be thoroughly cleaned before firing it up again.
A 5 or 6 bounce landing where it bounces higher and higher until it stalls and lands flat, maybe breaking a flex plate. Engine Damage unlikely, but your ECU gets it!
A hard gear up landing - naah, should be good to go.
A light cartwheel where the wingtip hits and it goes up on the nose, then lands on the back. Likely damage to components, but not the engine.
A landing off the runway, gears break out. Should be no damage at all.

I've experienced most of these. Never had engine damage, but have gone through several ECUs' and batteries due to fuel spraying all over the place more than anything.
Old 10-28-2014, 09:40 AM
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A excursion through the forest
Old 10-28-2014, 09:55 AM
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G4guy
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Or a loose start air line into the compressor.
Old 10-28-2014, 10:59 AM
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essyou35
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And then the mythical question is, how do you know if there are vibs? I've tried the screwdriver thing but I can tell you on a turbine with failing bearings I felt nothing with a screwdriver. I think that is a myth.

Sounds like the turbines are pretty tough. Glad to hear it, I worry everytime I have a minor misap.
Old 10-28-2014, 11:22 AM
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With experience after my tubine seized in the air can say:
1. Lubrication: No oil in fuel, obstructed oil needle. Bearing failure and this leads to all parts rubbing.
2. F.O.D: Damage to compressor cover, compressor, and difusor. Can lead to balance problems and bearing failure.
3. Not replacing bearings when you here them or feel them bad leading to bearing failure.
4. Balance problems: Turbine vibrates when spooling or running leading to premature bearing failure.

BEARING FAILURE IS THE WORST CAN HAPPEN assuming you don´t crash and burn turbine.

My turbine had a complete rear bearing failure and all components totaled. The repair cost where the same as what paid for turbine used. Needed compressor cover, compressor, oil needle, tube shaft, and shaft.

SO RECOMMENDATIONS
1. USE FOD COVER AT INTAKE
2. Filter fuel, have filter before pump and before turbine.
3. Use recommended oil for turbine.


Cheers

Juan
Old 10-28-2014, 11:27 AM
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ravill
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I did this to one of my JetCats.



Bob Wilcox sent it back to me with a clean bill of health. Thank God for FOD screens.
Old 10-28-2014, 11:52 AM
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essyou35
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Rav, so did it take damage??

Edit: Sorry seen the last line

Makes me feel better about getting grass in it.
Old 10-28-2014, 12:58 PM
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ravill
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Here's what it looked like underneath:



With so much debris underneath the FOD screen, I though for sure I'd damaged it.

After coming back from JetCat after some cleaning, there was no damage.

Certainly, this kind of repeated treatment is not recommended by any turbine manufacturer!
Old 10-28-2014, 01:38 PM
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Originally Posted by essyou35
And then the mythical question is, how do you know if there are vibs? I've tried the screwdriver thing but I can tell you on a turbine with failing bearings I felt nothing with a screwdriver. I think that is a myth.
Well think what you want it is not a myth, it comes with experience, the kind of experience that is difficult to gain by typing gotcha posts on RCUniverse. :-0
Old 10-28-2014, 01:54 PM
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essyou35
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Originally Posted by mr_matt
Well think what you want it is not a myth, it comes with experience, the kind of experience that is difficult to gain by typing gotcha posts on RCUniverse. :-0
Not sure what a "gotcha post" is. Hey some people can talk to the dead, others can feel vibs in a jet engine with a screwdriver. Im not here to judge I cant do either.
Old 10-28-2014, 03:04 PM
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I had an amt 450 in my fry beagle f18. it hit the ground with authority. the fire burned everything. The engine was beat up pretty bad. 2 large dents in the case where the gear were shoved into it. I tossed it under the workbench figuring it was toast. About a year later, I pulled it out again. It would not spin freely but it would move a little. I took it to a friends house for wednesday night build night, my favorite night of the week. We took the outer can off and it spun free as can be. We took turns banging out the dents in the can until you could hardly tell anything happened. (Big Thanks to Glenn Sheppard). Put it back together and it still spun perfectly. Searched around and found an ecu, pump etc. Test ran the motor several times and it ran as good as it ever did. I'm not sure the newer, lighter motors would have faired as well. Those amt motors are tough as nails.
Old 10-28-2014, 03:15 PM
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essyou35
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Lovin the war stories, keep them coming!
Old 10-28-2014, 04:00 PM
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as722
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A hammer.
Old 10-28-2014, 04:07 PM
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Fedex
Old 10-28-2014, 04:12 PM
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raron455
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Originally Posted by dbsonic
Fedex
Yeah, those motards could tear up a hammer with a q-tip!!!
Old 10-28-2014, 04:16 PM
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Originally Posted by ravill
I did this to one of my JetCats.



Bob Wilcox sent it back to me with a clean bill of health. Thank God for FOD screens.
Thats a signature Raffy landing right there!!
Old 10-28-2014, 04:58 PM
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LGM Graphix
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You do know you can get really inexpensive flower pots at home hardware right? I mean to each their own but I can think of better uses for my turbines


Originally Posted by ravill
I did this to one of my JetCats.



Bob Wilcox sent it back to me with a clean bill of health. Thank God for FOD screens.
Old 10-28-2014, 05:33 PM
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Me flying it
Old 10-28-2014, 07:30 PM
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Here is one of mine. It locked up while at full throttle in the air. No signs or any issues prior to this flight. You can see where the back fan welded to the housing.

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Old 10-29-2014, 07:30 AM
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Granpooba
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Originally Posted by ravill
Here's what it looked like underneath:



With so much debris underneath the FOD screen, I though for sure I'd damaged it.

After coming back from JetCat after some cleaning, there was no damage.

Certainly, this kind of repeated treatment is not recommended by any turbine manufacturer!
Will admit that I " Personally " do not know much about these model engines. But if this was " Real Life " engine with those blades, it would be getting some major engine work.
Old 10-29-2014, 08:35 AM
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essyou35
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sounds like G forces are not a major factor in causing damage. G forces from hard pulls or hard hits, so long as nothing hits the turbine. A long time ago I had a jet central turbine, and on a hard landing it shut off. It has flown a lot since then but I recently wonder it it may of rubbed from that, not sure why it shut down. It said LOW RPM and it was at idle on landing, and it hit pretty good but not hard enough to break anything.
Old 10-29-2014, 09:07 AM
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ravill
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Originally Posted by ianober
Thats a signature Raffy landing right there!!
Well, at least some of us are flying!

Old 10-29-2014, 09:38 AM
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Originally Posted by ravill
I did this to one of my JetCats.



Bob Wilcox sent it back to me with a clean bill of health. Thank God for FOD screens.
Why would you pile mud on the turbine inlet? Glad it come out ok.

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