Keith Wood wrote:
Okay, time for more wargaming.
Which would you guys pick, the Rotamax one-rotor, or a one-rotor
conversion of a 13B, and why?
I'm leaning toward the Rotamax (for weight and for the
less-experimental nature of buying a whole, running engine), but I
HAVE a 13B that is most of the way through an overhaul, and could
be made into a more-powerful one-rotor for half the cost of the
Rotamax.
. . .what I REALLY want is for the Rotamax guys to loan me one to
do extensive flight testing on my ultralight, but I'm not holding
my breath . . .
Keith Wood
I agree but there is yet to be a gear box available for the Rotamax.
As soon as that
happens it should be viable option. Are you willing to build a gar
box or belt
drive? If you are they might loan you one.
> Paul Lamar
I'm figuring that it would be simple to make an adapter for existing
gearboxes. My Notax has a factory-made adapter between the Provision 3
engine and the Provision 4 gearbox.
I'm also trying to find a belt-drive unit and solve all the problems at
once.
Keith
Richard Sohn adapated a Rotax or some other 2 cycle engine gear box to a
one rotor and has some bench test hours on it.
Richard Sohn <unicorn@gdsys.net>
Eric, get in touch with this guy. He can help you out real quick.
--
Paul Lamar ...No rotor no motor.
hi all, i have a couple single rotor OMC engines and have spent
considerable time studying them. i have modified one but have not
aquired an airframe to try it on. this is the engine where Moller and
Rotamax began. i feel it is no contest, the mazda will deliver much
more power without failure because of the oil cooled rotors. the
charge cooled rotor will never be able to deliver the power without
overheating. like all aircooled engines , there is a definet ceiling,
with the mazda we have not found it yet. that is one old A&Ps
opinion, wyo. walt.
The Rotamax is water-cooled.
Keith Wood
Not the rotor. Walt is correct the rotor is charged cooled.
http://rotarynews.com/node/view/667
http://www.freepatentsonline.com/6325603.html
http://www.patentstorm.us/patents/6325603.html
http://www.wipo.int/pctdb/en/wo.jsp?wo=2000036286
Wankel Gmbh Germany also used a charged cooled rotor.
I also think Sachs used one as well.
Paul Moller mentions it in this pdf.
He also mentions turbo compounding but he dismisses it
as not practical because of the need to reduce the RPM
of the turbo charger turbine from 200,000 to 5,000 RPM.
He was off on his turbine speed by a factor of two.
On a Mazda sized engine the turbo charger turbine speed is only 100,000 RPM.
Not a problem if a friction drive is used. Friction drives
with 100,000 RPM are available off the shelf.
Keith is your ultralight flying at the present time?
Paul Lamar
He said air-cooled ENGINES, above.
No, it's not flying at the present time, it's too dark out! ;)
Seriously, I'm halfway through an uprate project, a couple of mods, plus
new instruments and fabric, with one more day of work to do.
I wish I could add an engine uprate, too . . .
Keith Wood
What he said was "like all aircooled engines"
Paul Lamar
Wyo Walt and others on RotaMax engine,
A quick note on the RotaMax charge cooled rotary engine and heat. As far as
we know this is the only engine you will find that cools down with load. The
reason we are in the aircraft market with our partners Rotary AE and Airgyro
is due to this attribute. In any application where load is required the
charge cooling is a great advantage. When you apply max load and RPM to the
engine the internal temperatures go down due to the incoming amount and
velocity of air and fuel. In the Mazda the Oil Temp goes up due to the
additional load/heat. And as stated below it is liquid cooled as well, we
have several of the old OMC 5430cc air cooled engines as well, and the new
RotaMax engine while sharing some similarities is very different in several
positive ways from the original engine. The only applications where a
charged cooled engine is not good is light load and low RPM as the internal
heat will go up due to the minimal velocity of air and fuel passing thru the
rotor.
The current gearbox for the RotaMax engine is spur gear although over
designed as we are using a 160HP box (20Lbs)on our single engine at 60 HP NA
and 90 HP Turbo and a 300HP box (30 Lbs) on the twin engine at 120 HP NA and
180 HP Turbo and . Both boxes do use the BMW isolator as shown in the
pictures one is rated at 200HP (I believe) and the other at 400HP.
We believe the combination of over design gear load and the BMW damper
running the engines at 6000 RPM and below will provide a reasonable and to
be tested result.
We believe one of the biggest mistakes made in gearbox design is that the
end user says we want a 10Lb gearbox that will last 5000 Hrs and we believe
the key is that you can only request one of these variables for a successful
gearbox.
Eric Barger,
RotaMax Inc.
I think you mean 543cc and not 5430cc Eric.
Paul Lamar ...No rotor no motor.
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