Mailing List flyrotary@lancaironline.net Message #9621
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: Turbo post mortem
Date: Fri, 9 Jul 2004 11:07:14 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Thanks, Rusty
 
    Well, I was not certain whether to call Todd's incident a turbo problem or a situation whereby the Pilot got distracted by other things, was not monitoring the boost and it got away from him.  As best I recall there was no damage to the turbo  - JUST the engine.  So you could call it a turbo problem I guess, but I viewed it a bit different in that no damage to the turbo in the context of A/r sizing, overspeeding, etc..  It would have been nice to know what boost Todd was at when things did break. 
 
   From my limited experience in turbocharging two cars from scratch in the 1970s, I think the quick reving rotary is less forgiving of inattention to boost than a reciprocating engine (and I blew pistons before I got it all sorted out) where you might have a bit more time to react before things reach the breaking point.   
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
Sent: Friday, July 09, 2004 9:11 AM
Subject: [FlyRotary] Re: Turbo post mortem

I have read that the water cooling designed in to some automobile turbos is not really for cooling the turbo during operation.  It supposedly is to continue to provide some cooling after the engine shuts down. 

This is my understanding as well, but more specifically, it helps prevent problems caused by the average driver who has no idea what goes on in the engine compartment.  The owners manual for the FD states that you should let the engine idle for at least 30 seconds prior to shutting it down.  Even as minimal as this requirement is, how many people do you think do it?  When I was talking to Turbonetics, they said that water cooling wasn't needed for aircraft, since they get a guaranteed cool down period during descent, and taxi back to the hanger.  They also stated that pilots are far more willing to comply with procedures to keep their engine's happy :-)   

I believe Todd has done at least some of these modifications to his turbo which may account for his lack of turbo problems.

Not to be too critical, but isn't Todd the only one (so far) to damage his engine due to overboost induced detonation?  Maybe it's just me, but I'd call that a turbo problem :-) 

BTW, that was a very good explanation of a/r. 

Cheers,

Rusty (yawn)

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