Tudor Miron wrote:


   As I understand lengthening the rotor has almost linear relation with safe
available RPM that leads to almost linear relation with power?
What are other limiting factors? How much that phasing gear + hardware
weights? Are there drawings of those spring pins and why they are springed -
I understand that they are damping some sort of rotor lateral vibration/misalignment
or waht there is, but what causes it and how it is related with rotor weight?
Reducing the rotor weight we're going to reduce the loads those pins have to deal with.
   What about automotive applications? We still need torque down low so some sort
of turbo is inevitable. But may be it's going to be a bit different than
current common practice?
3 rotor engine - how much RPM we can safely have with 6 lbs rotors?  How
much power can we expect? What kind and how should we configure the turbines
to have lots of low end torque, excellent tractability and crazy power up high? 
   Remember I'm not an engine guy and I will definitely outsource engine
building to reputable shop. But I want to know as much as possible to set
realistic targets and requirements.

   Thank You
  Ted


The load on the rotor bearings is m*V^2 m vee squared.
m is the mass of the rotor. V is the velocity around the circle
path of the CG of the rotor.

So the RPM is the square root of the difference in rotor weight.

7/9 is .777 so my guess is 10 to 15% more RPM and power.
I would say maybe 12,000 RPM for a 7 pound rotor.

Normally aspirated it would be about 450 HP times 1.15
or about 520 HP for a 3 rotor. Turbo charged on alcohol and
nitrous oxide about  1400 HP.

For a 6 pound rotor 6/9 is maybe 25% more RPM or about 13,000 RPM.
HP 450 times 1.25 or about 560 HP.

Beryllium aluminum alloy rotor (density .076 pounds per cubic inch cast iron is .3) would be one quarter the weight so the RPM would double and so too the HP. Go for the gold :)

Those are off the shelf spring pins available world wide.

Paul Lamar

 Thanks a lot for your answers Paul,
What's the weight of ring gear? Wat's the aproximate (very rough) size of the rotor?

Why you start with 450hp for two and 520 for 3rotor? Is it P-port all out version? How about some street legal noise levels and exhaust gas chemistry? Where do we start than?

What are other limitations? - oil and water temperature at 12-13 - 18000RPM? Lubrication issues?

What are finish and surface (hardness etc.) requirements for rotor - seal slots, faces, ring gear adjusent and attachment points?

I'm talking to one source producing berillium alloys right now?

Thank You
Ted

4 dia x 3.1416 pi x .25 area x .3 density = .9 pounds for the gear.
The rotor roughly is an equilateral triangle 7 inches on a
side by 3.15 inches thick. The rotor bearing diameter is about
3 inches. 1.75 inches wide.

We start with 450 HP for a p-port 3 rotor NA engine at 10500 RPM
in both cases. 520 HP is a p-port 3 rotor NA engine at 12,000 RPM.

At 14,000 RPM a 3 rotor p-port engine NA would be about 560 HP.
Weight in all these cases would be about 260 pounds for a bare block
with cast iron end housings. Knock off about 100 pounds for aluminum
end housings.

The rotor is now used as cast in ductile iron. The face and pocket are now
machined all over. Only the RX8 rotor is hardened in the corners of the apex seal slots. In the case of Be/Al alloy rotor the apex seal slots may have to have a hardened steel insert for wear reason and strength reasons in the corners. I don't know for sure.

For titanium I don't know much about the steel or ceramic apex seals wear characteristics. Silicon Nitride ceramic apex seals are now widely used.

The oil temperature must be kept below about 220 F. I am not really sure about
that. Synthetic oil may be able to run hotter.

The size or capacity of the cooling system will have to be increased to handle the increased HP. Not so much in a car as the max HP is only used for a fraction of a second. Water temperature is also limited to about 220 F depending on the pressure cap to prevent boiling.

In all cases a wider rotor would be great as p-port engines would breath much better at RPMs over 10,000.

Paul Lamar