Mailing List lml@lancaironline.net Message #30522
From: Walter Atkinson <walter@advancedpilot.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Induction air filter
Date: Wed, 22 Jun 2005 09:49:23 -0400
To: <lml@lancaironline.net>
Scott:

  Please don't tell me that a 8:1 CR  IO 360 with a turbocharger that raised the inlet temp 100F is going to detonate running ROP. 

Oh, man, how am I going to do this? You asked me not to tell you. Oh well, what's a fella to do? <g> Sure can. That would depend on other factors like WHERE the mixture is ROP and the fuel used and the timing. Could happen EASILY. And, does... more often than we would like.

How about a supercharger that delivers 40" MAP to a 7.5:1 Lyc IO 520?  With no intercooler doesn't the inlet temp rise 100F or more?
 
I think you meant a Lycoming IO-540? Yes, and that one will detonate easier than the above example. Same scenario. Actually it's one of the most detonation-prone engines in the fleet, the TIO-540J2BD Lycoming gets that award (Navajo Chieftan engine). Running one without an intercooler can routinely result in light detonation on takeoff at the FFs recommended by Lycoming. If run according to the POH, essentially the detonation margin is so narrow as to be essentially none. We have REAMS of data on that engine and use it as an example in the class. We run one and demonstrate detonation on it--in real time--every 60 days to a class of 40-60 students. It's not like I haven't watched this in real time on a running engine at least a couple of dozen times. Anyone who's been to the APS class has seen this.

Who is Taylor?

Charles Fayette Taylor, Professor Emeritus
former director of the Sloan Combustion Laboratories at MIT.
Author of the authoritative, two volume texts on internal combustion.

You would enjoy having his texts as reference. The information in them is unequaled. They come highly recommended. Be prepared to spend a year or so digging through them. Whew! They are *complete* and I can't follow a lot of the math.

Walter
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