Mailing List flyrotary@lancaironline.net Message #11291
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] First engine run with Monster Prop
Date: Thu, 9 Sep 2004 19:14:45 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
Ok, got out today and fired up the engine with the new prop and gear box.  This is the 76x88 inch prop that is 2" longer than the one Tracy and Rusty have on their birds.  The static was 5400 rpm at 28.75" with ambient manifold pressure reading 29.75" (as best I interpolated). OAT was 87F.  Idle was considerably smoother whether due to increased mass of larger prop, new gear box or both.  I did notice the 2.85 has considerably less gear lash than the 2.17.
 
 Hi Ed,
 
Glad you got it running, and thanks for the numbers.  It still bugs me that I'm only getting 27" MAP, but I'm convinced it's a bum reading.  Hard to say how much the extra 2" of prop will effect the rpm, but that sounds a little lower than I was expecting to hear.  As you my recall, I went from 5250 with the B drive, to 5500 with the C.  However, now that I've re-worked the restrictive inlet, I'm at 6000 rpm.  I bet you still have some tweaking to do, but that's half the fun right :-)
 
So ya got some P factor eh?   Try it without the training wheel, in a 3pt stance :-)   Still running the left offset in the mount?   
 
Rusty (not looking like I'll get to fly the -3 this weekend, due to lack of oil pressure fitting)
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster