Subject: Kart wankel engine
From: Rotary Engine
Date: 1/9/2007, 7:08 PM
To: AARotary Engine


     >>> I want a 50 HP, 100 lb Wankel for my ultralight -- it won't
    arrive until
     >>> the rumors are killed).
     >>> Keith
     >>
     >>
     >>
     >> Keith,
     >>
     >> That kart engine that was mentioned of few months back was close
    to what
     >> you are looking for.  I think it's rated at 48hp...
     >>
     >> http://www.nova-racing.com/nova_gb/index.htm
     >>
     >> Heath
     >
     > That one is close, but no kewpie.  41HP at 7800 RPM, so it would
    replace
     > a Rotax 377 or 447.  A three-rotor would do the job though, and
    the bare
     > 2-rotor is only about 35 lbs so a three-rotor would weigh about
    50 lbs.
     >
     > I'm waiting to hear back from their American tech rep about
    pricing and
     > availability.  Going by the German site, the engine is over $5,000,
     > about a thousand more than the 447 and even more than the 50HP 503.
     >
     > Of course, that's a lot cheaper than having a dead-stick over the
    wrong
     > terrain!
     >
     > Keith

    for what it's worth, I've been following up on the small German kart
    Wankel.
    There are two aviation companies taking a hard look and using
    hardware in
    tests:  Phantom ultralights and EZ-copter.  Phantom had 135 hours on
    their
    test engine before it had a bearing problem in flight.  They were
    working on
    a bearing fix in August or September of last year.  They did change
    carbs to
    a Bing unit.  Phantom derated their engine from a claimed 50 hp to
    40 hp at
    7600 vs the 10,000 and claimed 50 hp as a kart engine.  They had a
    problem
    with the waterpump belt at 10 hours and went to a different
    belt.  They are
    looking at the possibility of a twin rotor in the 80 hp range but
    think it
    won't happen for 2-3 years.  Haven't heard anything else.  The
    EZ-copter
    guys are looking at 3 different engines for their coaxial egg
    beater.  They
    rate their version of the German Wankel kart engine at 46-47 hp and
    propose
    to use two of them, through a box to drive their rotors.  There is
    another
    small Wankel out there that looks similar to the AIXRO (German) kart
    engine.
    The Italians have a single rotor called a Saetta.  249 cc
    displacement vx
    the Aixro 294.  Oddly, the Italian mill is twin plug, the German's
    claimed
    that it wasn't worth the tooling expense to go to twin plugs on the
    Aixro.
    Film at 11.

    George W


Thanks for the update George..  I still think the scaled down rotary
engines (especially the twins) make more sense than a single rotor Mazda
(13b/2 = 6.5b?).  It will run smoother (easier on the PSRU) and probably
weigh less - the housings are sized for lower total output, and the PSRU
can be lighter weight because it doesn't have to deal with the torsional
extremes of the single.


Regards,

Matt-

Diamond Chris Dries <c.dries@diamond-air.at>

My pleasure!  I tend to like the twin-rotors in terms of the number of power
pulses that have to be damped.  Don't see why a single-rotor with a decent
flywheel wouldn't work, but you wonder about the flywheel mass required to
sufficient damping.  I just got an e-mail from one of the Wankel companies.
We were discussing the bearing failure on the RX-40 (Phantom's designation).
His comment was "...we are aware of the bearing failures you are talking
about with the German Wankel.  Part of that is due to the fact that their
bearing assembly is constructed of plastic!"  Whoa!  I need to get back to
him to make sure WHICH German Wankel he is talking about.  I'm not sure the
Phantom is the engine in discussion.  My company is looking at a
non-aviation application for a single-rotor and we're talking to everybody.
Hopefully, some of the spin-off information will be useful.

best,

George W


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