Paul what is the stock Hp/Torque of the 13B?
The information we have shows it as 110 verses the 101 for the 12A.
Royce

A lot depends on the porting and the RPM. Anywhere from 60 HP per rotor to
170 HP per rotor for the 13B NA. For aircraft use a lot depends on the PSRU ratio
as the tip speed of the prop is one of the limiting RPM factors.
The common PSRU ratio is 2.17:1 which limits the engine RPM to around 6500.
Not ideal for a rotary. A 2.85:1 would be a lot better IMHO.
Some are running that PSRU ratio and they can take off at 7500 RPM
and enjoy a lot more power.

About the best you can get normally aspirated then is about 120 HP per rotor
at 6000 RPM using what is called a peripheral port. See the ACRE NL web site below.
The typically side ported 13B is 80 to 90 HP per rotor at 6000 RPM.

Torque is not really an issue in aircraft as prop load is proportional
to RPM squared.

Turbo or super charged? I have no idea what will live for how long
but the sky appears to be the limit for HP as as much as 800 HP out of 
a 13B has been had at about 10,000 RPM. That also appears to be
pretty much the RPM red line limit for the current heavy rotors.
The new RX8 engine will have much lighter rotors with a higher
red line. We got a guy in Oregon that regularly gets 300 HP
using nitrous oxide and a 3:1 PSRU from his 13B for takeoff 
in his Coot amphibian.

The 12A will rev higher but you can get more out of the larger 
displacement 13B.

This is the NA four rotor Leman's engine. Divide HP by two.
The other curve is an early dynamic chamber 13B.
Probably around one of the first 2nd gen six port NA RX7 engines
about 1986.


Paul Lamar
 
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