Hi Paul,

    I have a BD5 that started life with a 650cc Hirth 2706 EFI engine.
   Short story, the
    vibration was tearing it apart, no one could solve it, 20 flight
   hours and had to put
    it on the shelf.
    Installed a RotMax 650 cc single rotor carbureted engine. Standard BD
   drive system,
    modified intakes, two CDI ignitions, MSD coil splitter to one plug,
   electric coolant
    pump.
    Engine cooling is fine, fan used only on the ground on hot days. It
   has more power
    than the Hirth and is swinging a higher pitch prop.
    So far it all works except the exhaust system. The first one (first
   pic) was 304ss,
    this was my first time around the block with a Wankel. The muffler
   failed but it
    missed the prop so the landing was just a little noisy.
    Went to 321ss, same configuration, working but worried about the 1800
   deg exhaust
    temp. I would like to put it inside and out the bottom, but again the
   temp. Also try
    to get the noise down a little bit.
    Pic's 159 and 163 are the last config it flew with. Pic's 160 and
   9652 is the inside
    setup that I am cautious of
    What do you think, any suggestions?

    Regards,
    George

    Wow a Rotamax wankel. How many engines did they sell?
    You did a better job than the Rotamax factory George.
    A good candidate for one of our coaxial mufflers on the side of the
   fuse.

    It looks like you already have parts of it. The inner pipe with all
   the holes.
    I'll send some pictures of the coax muffler with the next message.

    What is the takeoff RPM? Fuel burn?

    Paul Lamar

   A rotary powered BD-5 is one my dreams....LOVE it! Btw- doesn't a
   wankel powered BD-5 currently hold the BD-5 speed record?
   -Dan

 This could be your record holder,

http://www.airliners.net/photo/Bede-BD-5B/1060866/L/&sid=8719fa92aebb794ade55cdb85f461f97


 Erik

 No visible means of cooling 326 HP.

 Small world. David Lednicer is the guy that turned me on the Kuchemann&
 Weber book Aerodynamics of Propulsion.

 Paul Lamar


 Paul,
 There is a radiator visible under the fuselage to the right of the right
 main landing gear in the photo.

 Moose

 That looks like a scoop. The outlet appears to be below the prop shaft.

 Paul Lamar

 ----------------------------------------------

 This would make a good poor country fighter plane for shooting down
 insurgency fighters. WW I aviation history repeats itself :)

 Paul Lamar

 Oops, meant last pic...the view of the right-hand side of the BD-5
 -Dan


Hi All

I've read about torsional vibration in development of the BD.  The
answer was a "broomstick" drive shaft.  This is very small diameter
solid shaft that absorbed or cancelled the resonant frequency of the
drive train.

I've read the rotary engine website with great interest.  I did not
find a source there for the amazing engines and turbos.

I would like to find a new all aluminium 3 rotor Wankel for a project.
Any sources you know of?

Parker May

It lowers the resonant frequency (the RPM at which it occurs) but the
torsional vibration problem is still there.

Paul Lamar
   Hi Parker,
   Try http://www.rotaryengine.com

   Regards Keith



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