Greetings Paul,
I just stumbled onto this site.  I am an older pilot with a lot of older
aviation stuff in my barn.  I would love to get up to speed on this option.
  I have 2 projects that could benefit from a reliable running engine like
yours.

A/C Project #1, is an Osprey 2 I started a few years back.  I got the
bones mostly done and had to move so it got shelved.  I hope to get back to
it soon.

A/C Project #2, is my desire to build a WAR 50% spitfire. However I have
heard these little tinder boxes have some issues with high engine weight,
lack of narrow engines, and folks wanting to hoop 'em up and the frames not
liking it.

A/C Project #3, is a nearly new Israeli Dawn Star, single rotor, air
cooled engine.  It has about 10-15 hours on it, and I got it 'cause the
last owner hated the hard starting issues and opted for a Cayuna for his
U/L.

I have started reading over your stuff, and I wonder if this little engine
could be made to start easier, and be more dependable in the idle.  I
really liked the unit when I could figure out how to start it before my car
battery went dead.    On the stand, with a 3-blade, 52" ground-adjustable
prop set at 12.5°, I was pulling around 200-210 pounds on the scales hooked
to the back fence in my yard.  It seemed to be very reliable at rated
power, and would pull that fence as long as I had patience to keep the car
anchored to the back side of it...  It is rated in the literature at 40 HP
@ 3600 RPM.

Now my questions...
Is there anybody willing to help me with this engine to make it start and
function with the reliability I am used to in my C-85?

Is there too much concern over the air cooling vs. the water cooling?

Is it possible to hoop it up and use it in a larger design (translation:
real plane)?

Is it even worth making the effort on?

I have not seen anything on them since I got out of the Military in the
90s.  Are they still making them?  Parts if I need an overhaul?

Looking forward to learning what you guys are doing with these engines now.

Respectfully,
Dan Hennis
;-)


Project #1
We have a 3000 pound gross weight Coot flying with a 200 HP 13B rotary. I
have gone for a ride and it is a whole bunch of fun. The builder uses a
shot of NOS to get it up and out of the water in just a few seconds. Worth
100 HP additional. The builder claims he has used hudreads of pounds of NOS
on the cannon prof 13B Mazda rotary.


Project #2 Narrow engines. Here is a Mazda 3 rotor scale Spitfire
and a Mazda 13b 2 rotor powered RV4.

Have you checked the compression? You take the schrader
valve out of an ordinary compression tester gage and note the pressure
pulses as the engine turns over with the starter. You should get three
strong pulse's in a row all about the same amplitude.

If the compression is good hook a 12 volt battery in series with a six
volt battery to form 18 volts. If that works the 12 Volt starter is not
adequate.

There are 2.5 million Mazda rotary engines out there world wide.
They were sold up to 2013.

Air cooling is OK for a one rotor.

Where are you?

Paul Lamar

Paul,    I looked up the dawn star drone engine and stumbled onto a list of
rotary engines by the manufacturer. There have been a bunch of single
rotors over the years,
             george grimes