Another consideration, Charlie, might be the ability to produce 75% of 200
horsepower at FL180 or 200, without a blower. You might then be at a very
comfortable burn rate and a wonderful TAS.

Additionally, you should have enough steam to get up there pretty quick.
Might even be able to show Rusty how to get a 3000 FPM rate ;>)

Jack Ford


----- Original Message -----
From: "Charlie England" <ceengland@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, June 22, 2005 8:10 PM
Subject: [FlyRotary] Re: PP debate was Re: Single PP HP?


> Lehanover@aol.com wrote:
>
> > In a message dated 6/22/2005 7:23:37 AM Pacific Daylight Time,
> > 13brv3@bellsouth.net writes:
> >
> >     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?
> >
> >
> > Either side port (Bridgeport) or Pport will work just fine for
> > aircraft use.
> >
> >  This is your lucky day. I have a tube frame with a first Gen body and
> > a factory Pport engine. It has a Weaver Brothers external pressure
> > pump, but the front iron is intact, so you could go back to the stock
> > pump if you like. It has a trans but no rear end. Needs a Speedway or
> > similar quickchange. A nice trailer is included.
> >
> > The Pport has shorter intake timing than the "J" Bridgeport engine. It
> > idles much slower than the Bridgeport engine and has power a bit lower
> > in the RPM range than the Bridgeport.
> > It is not difficult to drive around the paddock with a tall first
> > gear. The Bridgeport is a nasty mess to drive around, and has around 3
> > HP until it get wound up a bit.The Pport is also still making power
> > right through 10,000 RPM if that ever comes up. This is a 12-A Pport
> > with about 300 HP at 10,000.
> >
> > The home built 13B Pport could be much better. It is just too easy to
> > build. As I pointed out with the 12A data at 7,500 212 HP and that
> > engine has the intake tuned to give best power at 9,400 RPM. Those are
> > real Ohio HP. Not those little California HP used to sell race engines.
> >
> > A well done 13B Pport with very mild exhaust work should have 230 to
> > 250 continuous at 7,500 RPM. Plan fuel pickups for a 45 degree climb
> > angle.
> >
> > If you only need 220 HP then the side port is quick and easy also.
> >
> > Lynn E. Hanover
>
> It's fun to bat around the incredible numbers a rotary is capable of,
> but for most of us 160-200 hp at cruise is about the most our airframes
> are designed for & can haul fuel for. Even big 4 seaters or very fast
> glass can't use more than around 225 continuous hp efficiently (75% of
> 300 hp). The airframe drag going up means you just waste gas making more
> hp than the airframe design speed calls for.
>
> The question I'd like answered is this: What configuration can be made
> the most fuel efficient while making hp in this range?
>
> Should it be p-port & 2.1 redrive, p-port & 2.85, side-port & 2.85, etc
> etc?
>
> My gut is betting on a small-diameter p-port & 2.85 drive, hoping for
> good takeoff performance with a big, fixed pitch prop & keeping fuel
> efficiency up turning whatever it takes to cruise at the above power
> range. My needs in an RV-7 would be in the 160-180hp (actual cruise
> power setting) & someone in an RV-10 would need 190-210 actual cruise hp.
>
> Charlie
>
>
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