Mailing List flyrotary@lancaironline.net Message #38910
From: John Slade <sladerj@sbcglobal.net>
Subject: Re: [FlyRotary] Static RPM
Date: Fri, 03 Aug 2007 00:09:21 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Chris,
If you're turning a 3 blade 68" IVO at 5500 static on full fine then you're doing VERY well. That's about what I get with 5 psi of boost, and it'll get you off the ground fairly smartly. Did you port that engine?

The other thing to watch at the higher throttle settings is your mixture. It won't hurt you without a turbo, but if it goes weak you need to adjust it richer before flying - and a rich mix might also get some some more rpm. Try tweaking the mixture a little at high rpm and see if it makes a difference to rpm. Also note that during the take-off (high speed taxi) run you'll reach higher rpm than you've ever been able to test static - watch the mixture at these higher rpm to be sure you don't go too lean there either.
keep up the good work.
Regards,
John

Christopher Barber wrote:
Ok, I know I have read about this somewhere, but not sure where or what I read means, but I finally ran my engine up to full power and was wondering what kind of numbers I should be seeing.
 
Even though I had some intermentant wire issue (SUPRISE) in that as I got over about 4500 rpm the rpm would flash in the hundreds and then go to zero.  When I throttled back to below 4500 ish, the reading came back.  This happened a few times.
 
However, later when I did it, the readings were better and I was able to run the rpm up to about 5500 rpm at full power on the Mistral Intake (so about 2534 rpm at the prop).  It seem to reach full rpm at about 3/4 (to 4/5) of full throttle and then mostly stablized.  Sounded smooth even though I am still running rich.  It seems to run much better with the mixture at about 9 oclock and bogs as I bring it to the noon position.  In auto tune it seems to be trying to lean but kinda slow and if I try to keep it at the 12 oclock position it seems too rich, so I think I will need to do some manual leaning and then go back to the autotune.  I am idleing pretty smoothly at about 1000 rpm.
 
Is this RPM range acceptable?  Is this good; bad? What should I expect? I was nervous to run it up like this, but I just kept telling myself that I am not gonna be throwing a rod or blowing a jug <g>.  If you remember I do not have coolant temp reading right now, so I closely monitored the oil temp and kept the run short, but I was curious as to what I could run it up to.  Thanks again.
 
All the best,
 
Chris
 
 

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