Mazda single rotor weight?

[[email protected]]

Atkins lists the weight of their single rotor "industrial" version of
the Mazda 13B at 80 lbs and their marine version at 130. I've got most
of a 13B apart on the shop floor with the idea of building a truncated
version for aviation use but I'd like to know if the weights are
anywhere near real world before I chuck the eccentric shaft in the
lathe.

I'd toss the bits and pieces in a bucket and weigh the whole lot but
unfortunately I don't have all of the little things needed to make a
motor actually burn fuel, like water pump and induction system.

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?
======================
Leon McAtee
Yes, I know I'll have to add the weight of a PSRU................

[Reggie]

1974 13B
Rear End Housing (Cast Iron) with oil relief valve.30.1 lbs
Trichoidal Section (Alum with Steel Liner).........13.5 lb
Front cover w/studs , no gear, Cast iron............25.5 lbs
Rotor and seals Cast iron................................12.0 lbs
Rear phasing gear Steel,withseal and bearing.....4.4 lbs
Flywheel end counter weight.............................4.5 lbs
Front Balance weight.......................................3.0 lbs
Excentric Shaft Single Rotor...........................10.0 lb
19 Cut down case bolts................................... 4.2 lbs
Aluminum front cover........................................6.3 lbs
Oil pump,drive chain,,mounting screws,............. 2.4 lbs
Oil pump chain tensioner assy...........................1.0
Water Pump housing (Aluminum)........................5.2
Water pump (aluminum).....................................3.X lbs
Shortened Oil Pan, Steel,...................................4.0 lbs
Water pump /Generator drive Pulleys & blots, ......1.6 lbs
Distributer drive gear...........................................0.5

BASIC ENGINE PARTS ONLY.............

[Russell Duffy]

> 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

[Reggie]

There was a gentleman at an airpark near Sacramento CA who
made a single rotor Timing belt, reduction,13B.
Installed it on a Dragonfly, Tandem Wing.

Last time I talked to him he was having a bad time
with it.

A Single Rotor has a very strong Reverse Torque that
is distructive at RPM's less than 1500.....Got a Big Flywheel?

Reggie

[Russell Duffy]

Hi Reggie,

It's always interesting to hear about folks working on rotary engine stuff,
who don't seem to participate in any of the rotary lists. I haven't heard
of too many people playing with single rotors, but I know there have been a
number of them over time.

I'm pretty familiar with the challenges to the single rotor. At the moment,
no real flywheel at all, so I'm not even attempting to run under about 2000
rpm. I'm in the process of adding some weight to the flexplate as a test.
The real problem is a severe resonance in the 2500-3100 rpm range. It will
be nice if that goes away with some weight on the flexplate, but only time
will tell. I might have to mess with the rubber dampeners on the redrive as
well. It's not a very high priority project at the moment, so I don't
expect to get much testing done until I have more time to devote to it.

Cheers,
Rusty

[Reggie]

Sounds like a second harmonic of the reverse torque at 1200
to 1500 rpm, where the rotational mass is sufficient to mask .

This will show up as an apparent vibration of the engine body
in the plane of rotation.

Reggie

[[email protected]]

>>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. <<

One mis-read on my part. I read 80 Hp as 80 lbs.

See http://www.offshoreboats.org/Engine.html A link from
Atkins somewhat disorganised web sites. 165 lbs quoted

http://www.americanrotaryengine.com/id15.html The 208 Quote from
another link.
===================
Leon McAtee