Mailing List flyrotary@lancaironline.net Message #8514
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Two problems solved, 2 more pop up...
Date: Sun, 23 May 2004 10:07:53 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
Can run more than an hour under 2300 RPM with occasion bursts up to 35 MAP for up to 15 sec without overheating.  The big key in that was running 80% water antifreze and some water wetter. 
 
I bet cleaning out your housings helped a little too :-) 
 
But 5 min after shutting down the turbo side of the cowl is too hot to touch on the top and I can smell resin.  It gets a little soft to tap on it and it is starting to look a little mottled and maybe yellow (if I let my immagineation run away).   
 
Sounds mighty familiar.  You could install a hatch, and also insulate the cowl, which would probably be the easiest method.  I had thought of trying to enclose the turbo in a thin stainless box.  The idea was to have a blast tube that fed the turbo enclosure, and an air outlet that left the cowling.  A small fan could also feed air to the box for use on the ground after shutdown.  Of course, trying to build all this around everything else is a problem in itself, but maybe just a fan at the top of the cowl, that ducts are out of the cowl would help.  
 
I also had problems melting my throttle cable, hoses, and the paint on the mount.  The turbo was in the factory shield, and these items were 1-2 inches away, AND covered in firesleeve.  For the record, firesleeve isn't very good for this purpose.  Thin stainless is better.  I recently bought a roll of .002" 321 stainless foil from McMaster Carr, which has been dandy for my current setup where the exhaust pipes run less than a half an inch from the cowl, and mount.   
 
New Problem: RMI tach no good.  According to my RMI engine monitor I have about 4300 RPM at 24 MAP.  At 29 MAP I still only have about 4500 RPM and at 35 MAP I am still at 4500 RPM static.  I dont buy it because it sure sounds different (faster).  So I have to install an accessory Tachometer....   
 
How is the RMI hooked up?  Have you asked them about the problem?  I'd be surprised if they can't find a way to help make it work.  Also, there isn't a lot of rpm increase for that last 25% of throttle travel, though the sound will change.  It might not be working as badly as you think.  Do you know any RC guys with optical tachs they use for their planes?  That would be one way to check it. 
 
Old problem still not fixed:  Low RPM: to keep it running it needs to be rich, so much that I billow smoke down 400 yrds of hangars.  It comes out in billows every 2-3 seconds.  Above 2200 RPM there are no problems (never were).  Will be trying some 460cc injectors instead of the 550 primaries I currently have.  
 
Sounds like you might have a sticking injector.  A good set of 460's will probably help in more ways than one.  
 
Dave Leonard (In red because Rusty alway takes the blue)(secret manifold my A## - lets hear the plan) 
 
Nothing secret about the intake.  The secret is what I'm going to do if the intake doesn't get me the power I want :-)
 
Rusty (just another "boring" day)
 
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