George,
Yes, at 7500 max rpm, I probably won't see 375hp. And at my normal cruise rpm of 5200, I'll be lucky to see 300hp. But that is why I'm building the pport, for that little extra over the side port n/a engine. I do have a ram-air system, but it only provides about 1/2" MAP boost. So, I'll take what I get. I anticipate the pport engine will be lighter due to a simplified intake and a new exhaust. If I can shave 10-15#, then a turbo could also be in my future.
In reality, I can hit VNE with the present motor, so any hp beyond what I have now is not good for much except higher climb rates.
Mark
On Thu, Dec 17, 2009 at 3:04 PM, George Lendich <lendich@aanet.com.au> wrote:
Mark,
I notice your Hp requirements for the 20B, which is 125hp per rotor. This exactly what I'm aiming for in a single rotor application, but would be happy enough with 115hp, if that's all I got.
Given that the motor can only gulp so much fuel and air and HP is dependent on RPM, which is restricted in our case. Are you considering any forced induction other than tuned inlet .
I've opted to use the RX8 high compression rotor to give me some addition HP and am using 44mm inlets to give higher inlet velocity, however my maths indicate even with this arrangement, 125hp might be out of the question. Certainly higher RPM would solve the problem, but that's not available with reduction ratio I'm considering and many are using, might get to 7,500 but that's it.
George ( down under)
George,
Yes, my Fluidyne cooler should easily do the job of cooling my current engine. But I am building a P-port 20B to replace this motor downstream, so I need to design for 375hp (375 x .8 = 300). The Fluidyne cooler is 297 cu in (core size is 9 x 11 x 3). Close enough for government work.
Mark
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