Can the rotary engine be used, or modified to be used, in a vertical
 position, ouput shaft end up? I have a helicopter project. I'm new to
 the newletter so this may have already been answered.

 Thanks, John

 I don't know how long it would last. The cooling oil drain back
 from the rotors would not work well. I would not take the
 chance.

 One of the best helicopter designs I have seen so far is the Ultra Light
 Mosquito. All shafting and gearing runs at high RPM up until it
 gets to the rotor head. This is the key feature that makes
 this helicopter light weight  enough to qualify as an Ultra Light.

 This is the lightest weight gear train possible
 as high torque implies heavy shafts and gears. Helicopters,
 like airplanes, fly on HP. HP is RPM times Torque divided by a constant.
 It is necessary to get the HP from the engine up to the rotor head
 and out to the tail rotor. The best and lightest  way to do this is keep
 the RPM up and the shafts small in diameter and use small light weight
 gears wherever possible. Then use final drive speed reducers or
 torque increasers near the rotor head and tail rotor.


 Paul Lamar

 So in this case you could use a relatively light weight bevel
 gear box on the output shaft of the rotary and then use a belt
 reduction near the rotor head. The rotary torque is only about 200
 foot pounds for a p-port.

 Paul Lamar

 Paul,
 Thanks for the input. The Mosquito is very good. I'm very familiar
 with it and have a similar drive on my helicopter. Even though the
 Mosquito would leave the ultra-light class with even a couple more
 pounds weight it would be very nice to use a reliable light weight 4
 stroke rather than a 2 stroke. That's why I'm interested in the
 rotary. I think it would only take a single rotor to produce the
 necessary 60-70 hp. I've always considered rotary to be a viable
 helicopter engine. I heard of a Hughes 269A that was converted to
 Mazda rotary.

 Thanks, John

 Since you need only 60 to 70 HP that shines a different light
 on the subject. Now I am not sure this engine will run vertical
 but it is not oil cooled like the Mazda. It might very well run
 in a vertical orientation. AIXRO are working on an all aluminum two
 rotor version of their 50 HP Kart engine.

 Contact Poul Henrik Woelfle AIXRO <ph.woelfle@woelfle-engineering.com

 They would have a lot to gain working with you as you would be
 doing the helicopter R&D for them for free. A priceless service
 for an engine manufacturing company.

 Here are some pictures of their one rotor product.

 Paul Lamar

Paul

With AIXRO's small size John could mount two of them on opposite
sides of a  4 beveled gear transfer case.  Think of the rear end
on a automobile.  Oriented properly, the remaining two PTO shafts
could go to the engine and tail rotors
The disadvantages of the AIXRO for the helicopter use are its high
rpms and short TBO.

Me, I would be contacting Richard Sohn and learning about his
one-rotor research and then spend some money on an aluminum front
housing.  The TBO would be greater and the power curve much wider
at half the rpms.  "No replacement for displacement"


Doug in Japan

Turbines are popular in helicopters and they have high RPM's.

Where did you hear about the short TBO Doug?

Quotes from the users manual.

"The XR50 is made exclusively for kart racing. Using the engine
in other applications is strictly prohibited without our express
written consent.  Race the XR50 on designated karting tracks
only, so you never run the engine at full throttle for more than
10 consecutive seconds."


This is because it is charged cooled but AIXRO has had a recent
break trough in silicon nitride roller rotor bearings which
can run at twice the temperature of steel roller bearings.
When the p-port is open over 5400 RPM at WOT the fuel oil mixture
is not cooling the rotor bearings. I recently suggested to
AIXRO a hollow water cooled eccentric shaft. Easy to make
on a NC mill in two pieces and welded together in the center
of the rotor bearing. A low torsional stress area. Also
easy to make is a hydro formed hollow water cooled eccentric
shaft once you pay for the tooling.

"Your maximum engine speed should be just less than the (limited)
maximum engine speed of 10400rpm (10800rpm with ceramic apex seals)."

"Without load the engine can accelerate much faster than a rev
counter can record.  At full throttle the engine can exceed
10000rpm within one (1) second.  From 2008 all Aixro XR50
engines are equipped with a rev limiter.  Still, the rev limit
can be exceeded in case of a malfunction, especially if you
run the engine at too high speed without load.  This can lead
to engine detonation (flying parts can cause serious injury)."

This is true of the Mazda as well. Maybe not quite as quickly.
Finn Lassen ran a Mazda WOT with out load or oil pressure for
that matter and it seized its bearings at well over 10,000 RPM.

"Engine service is due once a year or every 50 hours of operation
(whichever comes first).  Have the engine serviced by an
approved dealer, the American distributor RENNtech, or the Aixro
factory to maintain warranty for the engine.  A normal overhaul
usually includes a check to make sure the engine components are
still in good condition.  Sometimes it may become necessary to
replace bearings.  Otherwise no further service is necessary,
so the XR50 requires remarkably less maintenance than other
karting engines."

This is a 50 hour inspection which is similar to an aircraft
engine. It is quick and easy to disassemble and reassemble
as are all rotaries. It does not mean parts are necessarily
worn out.

Attached is the manual pdf.

Paul Lamar