flyrotary@lancaironline.net Mailing List Archive

Dennis,

So for that RPM, how long did your intake runners end up being?

For what its worth, I tried to emulate Tracy's dynamically tuned intake as well. But cowl constraints probably compromised the intake at the point where the TB is mounted. This is something I want to modify anyway. As it is things are tight enough that I cant even run any sort of air filter, so I do need to make some changes here - may as well try to do it right.

I know I had a picture of your intake - saw it just recently. But cant find it now. Could you re-post it?

Mike

From: Dennis Haverlah

Sent: Friday, February 12, 2010 11:19 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A. Renesis to turbo

I used the same 65 mm Mustang throttle body on both my original and new intakes. If I remember correctly, I believe I had a longer unused throttle travel with the original intake but I never measured it. I don't know the static rpm increase with the new intake - probably have that in my notes some where but my max. rpm at high altitude (8,000 - 10,000) increased 400-500 rpm. I estimated I went from 165 -170 HP with the old intake to about 185 HP with the new intake. This in in line with Ed Anderson's recent note that Mazda got about a 16% power increase at 6000 rpm with the DIE effect. I felt much improved acceleration the first time I took off with the new intake.

the new intake is based on dynamic intake effect (DIE) where the closing of an intake valve caused the moving intake air to bounce off the valve creating a pressure wave. The wave travels at the speed of sound to the other intake valve and arrives there just before that valve closes. This increases the amount of air and fuel that enters the combustion chamber. (As we know the rotary has no valves but uses the sides of the rotor for opening and closing the intakes.) I designed my intake to give max. performance at 6300 rpm.

If I had cut down my prop to 74" it would give me more clearance for the prop on my RV-7A and increase my top end rpm. Max rpm is about 6400 rpm with the new intake and the 76" prop. I'm really not needing higher RPM now.

Dennis Haverlah

Bill Bradburry wrote:

Dennis,

Did your static rpm increase with the new manifold? How much? Did you before and do you now have any unused throttle travel like Mike describes? Are you using the same throttle body on the new manifold? What is the MM opening of the Mustang body?

My manifold is very similar to your old one. My tubes are cut just above the injector bosses, which makes them a little (maybe an inch) shorter than your old ones. I have a 76 X 88 Performance prop which I am considering having cut down to 74” like Tracy and Ed when I send it in for final finish. I am using an aftermarket throttle body that is 75MM in throat diameter. This is the same size as the stock Renesis throttle body which is why I picked it. I had intended to use the Renesis body, but didn’t wait for Tracy to get the fly by wire done. I am not flying, but my static is 52-5300 rpm and I have a lot of throttle left at that rpm. The last probably ¼ of the travel is not used.

Bill B