Paul, what make is the rotary in the gyroPlane ?

Thanks, Steve Carlisle

for all you guys building your own PSRU here is a company selling drive  train parts.

http://www.drivetrain.com/parts_catalog/axle_shafts/axle_shafts_cars_and_pickup_trucks.html#FORDTRUCK


Paul Lamar


Hi Paul.
Do you think motorcycle drive chain can take  6000rpm?
What is your opinion simple to make chain drive PRSU?
I appreciate your help.


Luke F WINGS.

It might work. I think a late model Harley cog belt would work better.
Chain and belt drives take up more room in the cowl not leaving enough
for the cooling system. You also need an extra bearing on the outside
of the small e-shaft  pulley.

Paul


Paul, what make is the rotary in the gyroPlane ?

Thanks, Steve Carlisle


It was a Rotomax  charged cooled unfortunately.
Charge cooled rotaries are not going to fly for long on over about 70% power.

Also something failed in the rubber coupling, the gear box or the drive shaft
 and the test Vampire aircraft crashed.  The rubber coupling shown had a
5000 RPM rev limit.


The company then went bankrupt.

http://lightsportaircraftpilot.com/sadler_vampire_ultralightaircraft/index.html

I spent a lot of unpaid time trying to fix the many problems but I was
pretty much ignored.

They had a well equipped factory but it turns out all the machine
tools were borrowed or leased. The debtors got little.

Paul Lamar

We tried a motorcycle chain drive for a prop reduction on the Aixro
as we had the clutch and everything off the karting engine anyway.
I was never really aware how much noise and vibration the chain makes
until that day. Later a customer tried the same thing. We told them
it's pointless, but they tried anyway - and ended up with the same
result.

As Paul says, a (Harley) cog belt - with a torsional damper - would
be a better choice if you want to go down that route.

Just to comment on charge cooling: Charge cooled engines are good
if know what you do and set them up to run them within their limits.
They will not be as powerful as air/oil cooled rotor engines, but
in return they are smaller and lighter. So really it depends on
what you need and what you do with the engine, and the problem
with Rotamax was surely not charge cooling as such, but things
like understanding the limitations, getting everything right -
and not listening to Paul's advice ;-)

Poul Woelfle
ph.woelfle@woelfle-engineering.com

Very funny Poul :)

Oil cooled rotor, rotary engines have no stinking "limitations" :)
Jim Mederer at Racing Beat is getting 650 HP for a minute and a
half out of the Mazda 13B.


Quote from the AIXRO manual :) I think you wrote this Poul :)

-------------------------------------------------------------------
1.2. General Safety Instructions


 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.

------------------------------------------------------------
End quote.

Rotomax, Austro Engines  and Norton had classic problems with the
needle bearings mandatory in charge cooled rotors. OK for road racing
as you never spend more than a few seconds at max power. At first
Rotomax claimed well over a 100 HP and that steadily came down over time.

This pdf describes the problem  and soutions in a nutshell.
http://www.rotaryeng.net/Wankel-CC-paper.pdf

BTW Poul, I will be in Germany the first week in January and will
bring the ignition stuff with me. I know I am crazy to go to
Germany in the winter time but I will be in New York for
Christmas so I am half way there :)

Paul Lamar



Hi Paul,

Looks like we are going "off topic" for chain drive PSRU. Oil cooled rotor
engines do have "stinking" limitations.
One is cost - obviously not so much if you compare a mass-produced Mazda
against a small production engine like ours.

Others are weight and size. If you want to tie the engine to your back
and go flying, build a small unmanned aircraft or build a 120kg plane,
it does make a difference if you need the extra oil system and can
accommodate the different geometry required for an oil cooled rotor.

Besides this, even Jim Mederer's engine will have limitations. If you
run it at 650hp for 1 1/2 hours rather than 1 1/2 minutes, dry ice cooling
of the spark plugs may reach some limitations, and some other bits may
get a little hot as well. Not that any other engine of that size and weight
could supply so much power for so long, so I highly respect the achievement
and will keep my fingers crossed for the climbing record. But the point
I am trying to make is that there are always priorities and limitations.
And with decreasing engine size and weight and/or increasingly dynamic
load intervals (like in karting), charge cooling does make sense - even
if it's not the most powerful option.

You quoted the karting manual by the way. The karting engine is set up
for karting, where we can run the engine up to 11000 rpm. As you say,
the engine never spends more than a few seconds at max power. For
continuous load the engine will only run to 6500rpm and supply 35hp
(close to the 65% shown in the SAE paper). If Rotamax should have
initially claimed the highest number they saw on the dyno it was
their problem, not ours, and not a problem of charge cooled engines
in general.

Send me your schedule when you know it. We have not had much snow over
the last years anyway. Global warming, you know ;-)

Poul

I'll yield on the cost :) True for the back pack weight is critical.

I am not completely ever sure as we fly stand by.

All the snow is falling over here before it gets to Europe :)

I have both heaters working.

Jim has not gone the dry ice route yet. Plain old water injection is working.
It is more a limitations of the spark plugs and not the engine. The steel
liner in the Mazda is not in distress yet. Colder plugs are just not available.

Paul Lamar

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