Mailing List flyrotary@lancaironline.net Message #24294
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] PP debate was Re: Single PP HP?
Date: Wed, 22 Jun 2005 09:23:10 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
The side ports are a compromise to allow good power and low end torque. Aircraft wise I am going to be looking to buy or build 3 PP housings for my 20B. Much simpler manifolding, (3 pipes instead of 6) and better power at typical RPMs. I would like to limit my engine to 7000 if I can to reduce wear if nothing else.  
 
Hi Bill,
 
I hear what you're saying, and you won't have to search the archives too hard to find some of my old posts in favor of PP.  I can almost guarantee that I'll even try it at some point.  Every time I've been really ready to commit, I've ended up talking to people like Racing Beat, or Leon who have advised strongly against it for aircraft use.  I believe I had that same conversation with Bruce once as well.  Maybe someone can ask him again.  While Lynn seems to love PP for racing, I'm not sure I've seen him state that he thinks it's the best way to go for aircraft.  How about it Lynn, for, or against PP for aircraft use?  
 
While the power is appealing, it just sounds like there are lots of potential issues that make it less appealing for aircraft use, and we won't really know how it's going to work out until we have someone flying one.  Now I could probably tolerate the problems in the RV-3, because it's a toy, but if I were sinking loads of money in a serious cross country machine, expecting good cruise economy, noise levels, and power, I'd be steering toward a known solution.  Without having personal experience with PP engines, it would seem foolish to bet the farm against the opinion of the folks who are truly experts.   
 
As I've stated many times, I want to believe it will work well, but years go by, and no one is doing it yet.  I really do love the experiments that are in the works, and I want to see them succeed, but until they do, I just want to make sure folks know that this is a couple steps closer to the edge of experimental.  If that's what you want, great.  If you want something a bit closer to a sure thing, pay close attention to the way Tracy does things. 
 
For goodness sakes, if Ed offers you a really good deal on a "slightly used" engine, with a self pressurizing cooling system, just say no thanks :-)      
 
Cheers,
Rusty (wishing Ed a safe trip home)
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