Paul,

Made it to Sevenstock again.  Saw a few interesting things:

Dave Atkins showed up with the RV (recreational vehicle) and went through a
13B rebuild in the AM and then a Renesis in the afternoon.

Saw a new (to my knowledge) aluminum intermediate "iron" from Mazdatrix.

Also from Mazdatrix was an aluminum rotor.  I think the focus here was a
way
to keep the bearings from spinning with higher RPM applications by
machining
tenons/pockets into the gear/rotor.  Integrated the side rotor cover to an
iron rotor, too.

Racing Beat had one of their aluminum ends that had been flame-sprayed and
then lapped that ended up super smooth.

Pulled out of a barn just for Sevenstock, an Ercoupe forward fuse with a
13b
and sidedraft Weber.

The BMI drift car with a p-port 4 rotor.

..and the Mazdaspeed Rolex GT #70 car.  Sounds like they wrapped up the
manufacturer's title for the season.  The whole team showed up.  A young
Mazda rotary engineer made the trip to congratulate the team and see what
Sevenstock was all about.  No big announcement about RX-7/RX-9/16X.

Rotary owners are fanatics!  Lots of very clean cars.  It seems rotary
owners are almost as apt to make engine modifications as to make cosmetic
ones.  There were several dozen aftermarket single-turbo setups on daily
drivers.  Most of the bridge-port or p-port cars were trailered.  More cars
this year than in years past; a couple hundred rotaries in the same place.
I went up with the San Diego caravan of a couple dozen -7s.



Todd


I also drifted down to this event. Directly after the EAA 40 meeting ended
at Whiteman airport.

The aluminum center housing shown in the photo is a Jeff Doddridge creation,
as well the alum rotor and iron lightened rotor with alum sides.

There are several remarkable aspects of these parts. Most importantly, Jeff
is recreating the entire engine specifically for aircraft use. Jeff believes
that the rotary should initially have been produced favoring aircraft use,
and that they have not really made the best car engines.

On top of my list of the most significant improvements in the design, is
that the engine will be plugs up, and will be designed to be so,
specifically for aircraft. If you look at the image, you can see that the
oil pan surface is missing on the center section. What cannot be seen is the
water inlets on the top. He has designed the water jacket to receive coolant
on the top center, then flow across from center outward to each end housing
and out of each end housing, thereby insuring the best heat pickup possible.
There are two water inlets on top of the center section, perhaps dividing
flow fore and aft.

You can see in the photo he has built in a center bearing carrier for his
two piece e-shaft design (shaft not shown). This change has a couple
important improvements over the much heavier one piece design. Aside from
weight loss, the center bearing will mostly eliminate the wobble of the
rotor which would normally cause premature wear grooves in the center and
end housings. Also, he is developing an oil scavenge devise which will help
extract much of the dead weight oil from inside the rotor itself, and
improve cooling because the oil will flow into and out of the rotor better.

The center section is I believe a 3 piece design. The wear surfaces are
affixed to the water jacket with bolts and apparently an adhesive around the
edges. Although I could not view it, Jeff described how he machined cooling
fins to the inside of the wear plates to keep a uniform temperature across
the surface. This he said is critical because the sprayed on wear material
is susceptible to cracking where there are significant temperature
differences across the surface of the wear plates.

Not much to add about the alum rotors, the pictures say it all. They are
under development, perhaps 75% complete. Greater than 4 pound weight loss. I
believe the overall weight of the engine itself will be just over 90 pounds
when complete.

Jeff has teamed up with MazdaTrix to help with testing. They want to use
some of his designs on the auto racing engines they build. I prodded them to
put his whole engine in one of their cars plugs up, and when they retorted
"there's no oil pan!" I replied: put a dry sump on it and change the motor
mounts! Porsche has put dry sumps on their cars for the past 47 years....

Jeff will be working on the alum end housings in the future.

Lets hope Jeff can expedite completion. I for one, want some of his parts.

Ed Carver