---------- Forwarded message ----------
From: David Leonard <wdleonard@gmail.com>
Date: Oct 9, 2005 10:22 PM
Subject: Engine Torn down... Drumroll please....
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Busted side seals is the short answer. Why is now the question.
The first picture is the rear rotor as found. Half was stuck and worn thin near the broken end. The combustion gasses had scorched the rotor in that area and the outer oil seal was evaporated in that area. The inner oil o-ring was intact! Also note in the picture that there are no rubber buttons in the corner seals. Either I forgot to put them in (and never noticed the 3 extra buttons at the end of the re-build project), or they melted away without a trace when the combustion gassed got past the side seal. My guess is that I forgot as all the other buttons were in place, even where the other side seal broke.
That's right, the other broken side seal was on the front side of the front rotor (see first picture). The remaining part was stuck down flush with the rotor. The other half of the seal was no where to be found. Perhaps it was even responsible for my turbo failure? Interestingly, the oil seal o-rings there were intact, as were the corner seal buttons (although somewhat shriveled on this face).
When I checked the compression before tear down it was this, the front rotor, that had poor compression on one face. But the rear rotor seemed to have OK compression. I think the smaller hole between the two parts of the seal created a jet that damaged the oil o-ring.
|