"Weinstock, Rob" wrote:

One of the things I'd like to understand better is how/why the 13B is
superior to the Renesis, breathes better, but makes ~66% of the peak
power.

Otherwise, very informative!

Regards,

Rob

They raised the RPM where peak power is generated by adding 30% to the
intake
and 17% to the exhaust port areas.

HP = (Torque x RPM) /5252

Assume for the moment torque is constant.

So 8500/6500 x 185 HP is 240 HP.

I also think they made some sort of improvements in the oil pressure
system.
I am pretty sure the rotors are not significantly lighter in weight.

A peripheral port version of the RX8 motor should generate well over
325 HP with a Lemans type fixed intake system at 8500 RPM. Even with
side exhaust ports.

I don't agree the RX8 engine is a step backwards. Perhaps a little more
heat is rejected to the cooling system but the later timing of the side
exhausts ports does indeed result in more energy being extracted from
the fuel.

Until we have an RX8 engine on a dyno I don't think we will find out
what
the best BSFC is. I am sure the BSFC at low RPM/power levels is far
better than the older engines. That was Mazda's main focus on
developing
the side exhaust ports.

When the electric assisted turbo charged version of the RX8 engine
appears
you will see much better acceleration performance out of the RX8.
Probably exceeding the acceleration performance of the stock 1995 third
gen 260 HP sequential turbo charged RX7 despite the extra weight of
the RX8.

Paul Lamar

The fly in the ointment is the rpm where the max power is achieved.   I
think 8500 rpm of the Renesis  is useless to us.   We are going to be
operating between 5000 and 7500 rpm.  I doubt many will be operating at
7500 except for take off.  The question is which engine is better at
6000 rpm.  That is the sweet spot.    Jerry

Well yes as far as bearing load but 8500 RPM is possible for racing
by using  shorter prop with wider blades and the 2.85:1 gear box.
IMHO racing is where we must prove the rotary as a viable aircraft engine.
It is also the fastest way of achieving that goal.

Paul Lamar

 
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