Mark Wrathall wrote:

Mark wrote:
"...He gave me a copy of a free drag magazine called

 Drag Sport. It has an articale in the rotary by Jim Mederer in

it

which has

 some good points on the differences in thermal stresses between

the

leading

 and training plugs."

Paul wrote:
Mark can you scan that article and upload it?

Mark wrote:
Sorry Paul, I left it on a table in Copenhagen airport. Brian, can you

swing

by Hayes and grab another copy?

The gist of Mederer's article was that the trailing plug see's a duty

cycle

of over 70% immersion in combustion gas, were the leading plug is down
around 25%.

Interesting.  The leading plugs always have slightly more wear & tear on
them when I change plugs at around the 200 Hr. mark.  Wonder if the higher
duty cycle on them  is another reason for the smaller hole on the trailing
plug?

Tracy

I think it would be less confusing if we called them the upper
and lower plug.

Paul Lamar

Just a hint. The Trailing plug would be the Upper and the Leading plug the Lower.
Both words, Lower and Leading start with "L", a memory bridge.
Now, since the lower or leading plug is longer in the combustion chamber, perhaps
the exposure times should be reversed? 70% immersion in the combustion gas for
the lower and around 25 % for the upper plug?

Rolf Pfeiffer

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.