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A question about turbines...

Posted By:
Jonathan Silva
26
Posts
15
#1 Posted: 6/22/2011 19:12:05

Thrush Aircraft brought one of their planes by my school yesterday for a presentation and my instructor had a question for me which I just did not know the answer to. Hopefully someone around the forums here has a good answer for it, whether actually correct, or anecdotal.

The plane they brought in had a single turbine engine, but when the engine was shut down the prop was feathered. Anyone know why the prop is fully feathered when shut down on a turbine? Being multi-rated, I understand why a prop would automatically go to full-feather when there is a loss of oil pressure in flight, but we have feather locks on our seminole to prevent that on the ground.



Curt Burris
8
Posts
0
#2 Posted: 6/22/2011 22:19:42

The prop feathers so it doesn't blow the pilot's hat off when he gets out.

And to make hot turn-arounds without interfering with fueling and reloading operations.

If he needs a technical reason, it's because it's probably a Pratt and is detailed here;

http://www.studentpilot.com/interact/forum/showthread.php?13864-Why-feather-at-shutdown&s=a2613935c1efcef02d9a73edcd0ed4a1

Hope this helps,

Curt

 



Louis Knapp
Vintage Aircraft Association Member
23
Posts
16
#3 Posted: 6/22/2011 23:50:52

The free spinning turbine will let the prop spin for a long time after shutdown if it isn't feathered.  There is no lubrication after the engine is shut down so it is undesirable to allow the prop to continue to turn.  That's also why props are strapped while planes are parked.

 

To digress from the thread slightly,  Does anyone know where I can find the rules about Young Eagle flights with turboprop airplanes?  I heard Turboprop airplanes could not be used for Young Eagles but haven't been able to find any information anywhere in the EAA online resources.  Thanks....Louis



Todd Stovall
Young Eagles Pilot or VolunteerHomebuilder or Craftsman
49
Posts
7
#4 Posted: 6/23/2011 07:44:09

Louis,
I’ve never heard of that one. As far as I know, there’s no prohibition on turbine/turbo prop powered aircraft participating in Young Eagle flights. I too couldn’t find anything online saying it was a no-no:

http://www.youngeagles.org/volunteers/resources/content/YE%20Resource%20-%20EAA%20Young%20Eagle%20Pilot%20Guidelines.pdf

Anecdotal evidence is not proof, but I’ve been at many YE events and rides were given in a Bell 206 Jet Ranger so it’s being done, right or wrong.



RV-10 N728TT (reserved), Emp/Tailcone & Wings done, working on the Fuse. Location: Dumfries, VA (suburb of DC), EAA Ch 186