david mccandless wrote:

Hi Paul, Don D and I have been chasing the the cooling problem around
for a while over here and following the excellent articles of recent
times on this site. It came to me last night that it might be possible
to let the coolant enter the engine low on the flywheel side and take
the hot coolant out of both coolant ports up on the front housing. Has
this been done before and what is the general opinion of the idea? Maybe
incorporate it in the R Sohn endplate. Seems to me, that this would
promote a more natural flow and thermal syphon backup in an airplane
application, whereas the present system is really only right for a car
situation. BTW, I have located a planetary gear set with 2.4:1 ratio. It
is used in a Borg Warner35/40 transmission, very common in  Falcons,
Valiants Toyotas and Sigmas and even some 6 cyl Jags in the 80s. Having
said that, my engine expert has built his first single rotor engine and
his first remark was, that having a main bearing on the E shaft each
side of the single rotor,he was confident that this little engine would
sing happily all day at around 8000 rpm for 120HP. That now puts the
optimum ratio for prop speed at around 3.2:1, the same as is in the
Mazda auto Tx. This Mazda unit, I may say, is of very high quality
manufacture, and looks a hi- tech item when compared to the C4/C6
equivalent. I humbly invite all comments, especially on the cooling
idea. Dave McC

The main reason Mazda does it the way they do it is to try to
equalize the temp on the engine from side to side. One side is
hot and the other cool so the block tends to distort into a banana
shape.

When you say block Paul, are you referring to the rotor housing distorting, or
the rotor and end housings?

Its mostly the rotor housings I suspect.

The big loads are on the rotor bearings and not on the mains.
Rotor bearing loads limit RPM so things don't change much one
rotor or two.

So lighter rotors would allow higher RPM's to be run safer? How much could a
12A rotor be lightened, or/and a 13B for that matter?

About a pound with a 5 axis NC mill.

If I am reading the main bearing load chart correctly, 6k seems to be the best
rpm for equal load on the main bearing.
The rotor bearing load chart seems to show the rotor bearing load is less
right at 6k as well.

True.

If I am reading Fig. 3-40 correctly the flow is from the front at about 1
o'clock through the engine, and returns from the rear housing down the sides
of the rotor and end housings back to the front housing. Correct?
Royce

Also True.

Paul Lamar

 
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