Hi  Paul,  I am in Australia and a motor mechanic for the past 50
 years and have NEVER  as much as taken the plugs out of a rotary
 engine!!!  I had someone come to me once and asked if I could time the
 engine, "no worries said I", but I looked and said I think you will have
 to take it to Mazfix, he did not have a manual for it so I had no idea
 where to start.
                 Anyway I have been building a experimental helicopter
 with my son and we now have it flying (just getting the bugs out), I was
 interested in the comment by some how the Mazda rotary is unlikely to
 seize or stop, because of lack of all those things like
 pistons,rods,valves,camshafts, breaking, which can happen in a instant
 in a recip. engine.
                Can the rotary motors be operated vertical, ie. with a
 dry sump? Some of the engines pictured on your site appear to be dry
 sump engines, I was thinking of possibility of installing in a Rotorway
 helicopter, you do not know of anyone who may have tried/or succeeded in
 fitting one?
                 Their power to weight and apparent smoother drive along
 with the ability to keep running appeals to me.

                 I await your thoughts,   John Burey,   Charleville,
 Australia.

 We have several people interested in helicopters on here.
 I don't think it would last vertically but I could be wrong.
 Nobody has tried running a Mazda vertically to my knowledge.
 I would think the 9 pound rotor would wear out the end housing
 it was resting on but I could be wrong.

 Somebody is working on some aluminum rotors which may change
 the situation.

 Of course you are not risking much money as it is unlikely to quit
 running. It may wear the end housing more rapidly but these
 end housing usually last up to 3000 hours.

 Rotary cars typically go 300,000 miles if the oil is changed and
 it is not allowed to over heat. I have owned six since
 1972. Not all have had 300,000 miles :) Just one or two. My current
 2004 RX8 only has 30,000 miles but I have a beater I drive
 every day.

 Paul Lamar


Hi  Paul,  That was quick!! I guess that the side seals, or whatever
they are called would have to take the weight of the rotors on the end
housing, may be inviting trouble especially if one could use a reduction
gear then to the final drive and have a engine with . Thanks for your
thoughts, I will follow the discussion re these motors in aircraft, it's
always a pet hate of mine that a engine can be perfectly fine and
producing good power and as you say a "hand granade" goes off inside and
futttt!!  it all stops!
         Thanks again for your comments,   John Burey.

I think if the rotary had been perfected before the piston
engine people would laugh at the piston engine as being
a rube goldberg device.

BTW Sachs built some rotaries that ran on their side for
lawn mowers. As I recall they did not have side seals
on the bottom of the rotor. That might be something to
try with the Mazda. Just leave out the side seals
on the bottom side. I know the engine will run fine
without the oil seals as I drove my Cosmo for years
with leaking oil seals. The O-rings had melted.
Since that time Mazda changed the O-rings
to a higher temp material.

It would not be hard to set up a junkyard engine and try it.

You will have to go to Sydney or Brisbane to find a cheap 12A to set
it up and test it. If there is one country in the world that
really needs a rotary powered airplane it is Australia.

Paul Lamar


Hi Paul,

What about 15% of rotary working time in vertical and 85% in
horizontal position as in case of VTOLs? Dry sump system
effective for both positions?

Sincerely yours,

Viktor

Slovenia, Europe

Better than 100% vertical. Should work with a good dry sump.

Paul Lamar