Hi
   Do you have a HP / RPM graph for a 13B engine.

   Paul M

   Stock side port or or P-port?

   Here is an early 13B of around 1989 and some others.
   Note the 800 HP drag engine is running on Alcohol
   and can drive a 2000 pound car to 153 MPH in the
   quarter in less than 8.66 seconds.
   The engine is VERY ROBUST. That is about 4 HP
   per pound of engine weight.

   Paul Lamar
   --

  Weight?  With more than 400 lb-ft of torque, there ain't much
  weighting when this rotary leaves the line!
  j [pun] d

 Hi
 Thanks for the info. Could you run a rotary without a PSRU and  using a
 small dia prop, My aircraft needs only 100-110 hp for T/O and about 80 for
 cruise I know there are other options one rotor ect, but the two rotor
 takes
 my fancy
 Paul M

 You wind up with a poor power to weight ratio and a inefficient
 prop. HP is almost a straight line function of RPM. To get
 the engine to run smoothly at 3000 RPM you need to start with a side
 port that is about 200 HP at 7000 RPM so 3000 RPM would be about
 86 HP. Not good and it would weigh about 260 pounds firewall
 forward. The intake runners would need to be about four feet
 long. Rotary engines are all about RPM. A turbo charger would
 help. A super charger would burn more fuel. Not a bad way to
 go if you don't mind the fuel. You should be able to get it
 up to about 100 HP at 3000 RPM

 Paul Lamar

Hi again
Ok this is the A/C as you can see it is no jet The radial engine is now gone
long story ,so what psru ratio would you use, even though I said that I need
about 110 HP for T/O if I had upwards of 160 it would come in handy from
time to time, also for the engine it seems that I would only need a low
tuned one.

Paul M
    


The Rotec R2800  radial Specifications:
Propeller / RPM Fixed 76" Diameter x 51"Pitch @ 2,400 RPM.
(You need the large diameter prop for good take off performance.)
Dry Weight with Acc's (Starter Motor + Alternator + Carb) = 102 Kg
That is 224 pounds. In our ball park.

There is only one choice of gear ratio from Tracy Crook to get the prop to
rotate in the right direction. That is 2.85:1. To get the
prop to rotate at 2400 RPM the engine will be going  6840 RPM.

A p-port engine is easier and cheaper to build than a side
port engine as suitable side port intake manifolds are almost non
existent. People have kludged manifolds by cutting down stock
manifolds but it is a crap shoot.

HP will not be a problem. A Holly carb will work fine. It will
idle like crap but so does a radial. EFI and a slide throttle
will make it idle better.

Installed weight may be higher by about 34 Kg more but Racing Beat aluminum
end housing can be had for an extra $5000 US saving about that
amount of weight or more.

Putting the rad under the fuse with long hoses will help the CG
with the stock cast iron end housings.

Paul Lamar

Paul and Jeff,
For some reason I have 300hp for a two rotor as the holy grail
for a p-port engine. Was that at higher rpm?
Also keep seeing requests for about 100hp, which is easy
for a one rotor.  Is there enough market for a 140+? hp
single rotor with RB end housings?  Easy to derate,
even to 80 hp @ about 140lbs FWF with Ross style PSRU
and Jeffs'  mounting plate.  How about it everyone?

Dan F

That was at 9500 to 10500 RPM.

Paul Lamar