-------------- Original message from "George Lendich" <lendich@aanet.com.au>: --------------

Bill,

I have stated this before and I will gain, my calculations indicate a 44mm inlet ( per rotor) being the size needed to 7,500 rpm - giving max inlet velocity ( of 100/120 mph). It wasn't until I seen that the Powersport PP inlet tubes were 44mm that I was reassured I was on the right track. Others that we know push for the 3" ( 75mm) TB, such as the Renesis TB, nice that it is.

 

Not many builders will go to 7,500 rpm so 44mm is slightly overkill.

Probably could go as low as 38 to 40mm for lower RPM, but I would have to crunch the numbers. At the time I was thinking I would have to go to 7,500 RPM on the single rotor to get max take-off performance, so worked with those numbers. Of course the lower the inlet diameter the higher the velocity and the better the VE.

 

Lynn spoke of 38mm and 44mm chokes, If I remember correctly and chokes they are in his racing application of much higher rpm, but the trade-off is inlet velocity.

 

I know one of the ex-Powersport people are making ( machining) 44mm PP with 2 piece inlet tubes and fitting them to housings with O rings. I believe this service is available to anyone interested. Information passed to me was that Powersport never had any sealing problems after they went to this arrangement. Believe you me, they spent a fortune on development.

 

I'm just wondering how I'm going to get my housing over there to get it done.

George ( down under)