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Old 05-31-2009, 11:09 AM   #26
joff
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Join Date: Dec 2008
Location: Mesa, Arizona
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Quote:
Originally Posted by vex View Post
8 cycles on a single rotor test bed. Just because you have a pre-ignition event does not mean you'd have a catastrophic pre-ignition event.
Yeah, I missed the part where 1 cycle = 2.5 hours and thought it was meant 8 rotations of the rotor which sounded absurd.

Quote:
Originally Posted by vex View Post
As for speculation on why the ash causes pre-ignition events it's nothing more than a few ideas being passed around. As it stands right now the Pre-ignition is a direct result of ash because of carbon build up on the combustion surfaces. The carbon build up carries over heat causing the pre-ignition event where the gas reaches its flash point with contact to the surface. But that's just a theory.
This theory could be tested by replacing oil with ashless oil and seeing if a high preignition rate continued. I presume carbon build-up accumulated would not instantly vanish?
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