Paul:

Since I've never even seen a rotary installed in an aircraft, I ask that
you give me a little slack in the stupid-question department...

Has anyone tried mounting a Mazda rotary on its side (exhaust down/plugs
on top)?  It would seem to make sense to me to have the exhaust on the
bottom, away from motor-mount structures, away from side cowlings, and
allowing one to keep all the hot surfaces below most critical
components.

I know sideways-mounting would mean that p-port intakes would be down on
the bottom too, but having long tuned intakes would bring them right up
alongside the engine.

Also ... wouldn't having a sideways mount still make running coolant
lines fairly easy ...


I've been staring at you online photos for the past couple of days
wondering if it would work.


R Berglund

I assumed this was the case too until I found out the engine was lower
by about 1/2 inch right side up.

Those that say it gives a lower cowl are forgetting the
spark plugs stick up.


I think this whole
plugs up thing got started back in the early days when all Lou Ross
had to work with was the distributor version of the Mazda rotary.
Lou was the guy pushing plugs up.

In real old engines with distributors it is next
to impossible to lower the height of the distributor.
In those cases IMHO it is better to convert to electronic
ignition rather than run the engine plugs up.

The big drawbacks are the volume of the special sump required and
the difficulty of engine  mounting.

The big draw back to my way of thinking is the complicated
oil pan required. This adds to the effective volume of the
engine which of course uses up more room in the cowl.
The other major drawback is, it is hard to bleed the water
jacket of trapped air risking overheating. The stock upright
location places the water inlet and outlet at the highest
point on the engine.


This is the main reason it is not a good idea to run
plugs up.

The bottom of the leading plug is the hottest part
of the rotary. It is essential that this gets cool
water. If it is the top of the engine one could
get a steam pocket and all sorts of bad things
could happen. Everything from shorter plug
life to detonation and rotor housing melting.


Paul Lamar