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

John,

our engines work in this position(s).

Best regards ...

Mario Haeberer
WANKEL AG
Germany

Do you have some ready to ship Mario?
What are the specifications.

Paul Lamar


Paul,

not so fast;
what are the requirements of John's application?

Mario

He needs 70 HP.
Helicopters run pretty close to 85% max HP continuously.
Here is a youtube video of Mario and his engines.
http://www.youtube.com/watch?v=DgoM8EU29Ws

Paul Lamar

 75 hp are possible with the LCR - 814.
 What is the gear box for the main and the tail rotor?
 http://www.wankel-ag.de/seite1_e.html

 Mario


Mario,
The LCR 814 has enough power and low enough weight. The helicopter
uses special cog belt reductions and drives, no gear boxes. Engine rpm
of approximately 6,000 rpm is good. With the present design no
additional reduction on the engine is needed as the helicopter was
flown with a vertical Rotax 582 without gear box. I was at AERO
Friedrichshafen this year but was not looking for an engine at that
time. For aircraft (helicopter) use what is the expected TBO?

Thank you, John McEverett

I was there too. Perhaps I talked to you and forgot. Let me know if
you are going next year and we can get together. We usually
have a rotor head beer fest on Friday night at a hotel.

Paul Lamar



Paul,  I have a thought on a verticle Mazda rotary. The oil system supplies
lubrication oil through the two journal bearings to the eccentric shaft and
through the shaft to the rotor bearings and accessory end thrust bearing and
drive chain and to the cooling oil discharge.  With  the oil plumbed to the
needed locations and the shaft turning 6000 RPM  adgitating it there doesn't
seem to be  much of a problem with that. There are however three areas which
likely would be major problems.

The thrust bearing which centers the E-shaft
lobes between the side housings will be seeing a constant load, not as high
as from the clutch on a manual shift car but continuous.


Item two is that
the rotors will be laying on the low side seals adding friction load and
increasing wear. Intuition tells me that shortens engine life.

Lastly and
probably the deal buster is that steam will accumulate in the upper (drive
end) side housing and eventually alter cooling of the upper rotor housing.
There is no control over what cooling passages the steam will circulate
through. Trying to pipe the steam away from the housing  it would be
problematic getting steam rather than water.  In the standard horizontal
Mazda the steam rises to the top and returns over the charge cooled intake
area of the housing which  can tend to equalize the temperature across the
housing. The water outlet is also at the top which permits stem to leave the
engine block.

george grimes