wrote in message
oups.com...
Atkins lists the weight of their single rotor "industrial" version of
the Mazda 13B at 80 lbs and their marine version at 130.


Can you point me to that info on Atkins web page? The only weight I found
was 208 lbs for the industrial engine "as shown", which was pretty complete.
80 lbs with stock iron end housings just ain't gonna happen.

So what I'd like to know is if these numbers can be duplicated without
having to resort to expensive aluminum end housings. Anybody out there
with firsthand experience with single rotor 13B's?


I have a single rotor installed on a Kolb Slingshot at the moment, but I'm
still a long way from getting around to finishing the plane. I'm currently
in the initial stages of engine testing, and trying to resolve some
resonance issues before I break something.

I kept pretty good records of the weight as I built the engine, and noted
the following:

- Bare engine made from 93-95 REW parts. There was no oil pan, CAS, intake,
exhaust, alternator, oil filter, etc. The front cover was installed, as was
an automatic counterweight, but no flexplate. 108 lbs

- Above engine with a half inch aluminum mounting plate bolted to the oil
pan holes, and with an RD-1C redrive- 164 lbs

- Total weight, minus prop, which includes everything engine related (mount,
coolers, hoses, engine computer, alt, everything)- 240 lbs.

Note that this with no attempt to reduce the weight from stock parts at all.
I was interested in getting a baseline to work down from. For many planes,
aluminum housings will be necessary, since you can lose about 25 lbs that
way. Unfortunately, at the moment, I don't know of anywhere you can buy
them. Racing Beat never finished their front housing, and doesn't even sell
the rear housing now due to the rising cost of the plasma coating process.
Hopefully, someone will make some aluminum housings in the near future. You
can also trim at least 10-15 off the weight of the redrive that I'm using,
since it's way overkill for a single rotor.

Atkins was having a belt drive made for the single rotor, but I haven't even
seen a picture of one. Did they ever become available? If so, any idea
what they cost, or if they work?

Cheers,
Rusty