>     Any rotary powered BD-5s under construction or flying?
    >
    >     Jim Rudholm
    >
    >
    >     The [Mazda] Rotary is too big for a BD-5. Rather it's too
   heavy. The
    >     BD-5 is
    >     designed around a 3 cyl 2-stroke engine. The design weight
   was about 150
    >     pounds. Less than 50 hp. Several have been built using the
   Rotax 2
    >     cycles. If a proper single rotor is produced, it could work.
    >     Bill Jepson
    >
    >
    > Jim,
    > Actually, the BD-5 was originally going to be powered by a German
   Hirth
    > two cylinder two stroke air cooled engine. That engine was unreliable
    > and was Bede's downfall which brought on bankruptcy.
    > The Japanese Zenoah three cylinder two stroke engine mentioned above
    > might have saved him but it came along to late. Corkey  Fornof
   (he did
    > the BD-5J flying in the James Bond movie Octopussy.) swears by
   the Zenoah.
    > Numerous engines have been tried with mixed results and several
   failures.
    > Today the three engines offered by  Ed "Skeeter" Karnes of
    Bede-Micro
    > Tech are a new and improved Hirth, a Solar T-62 turboprop and for
   those
    > with deep pockets the JET!
    >
    > http://www.bd-micro.com/ <http://www.bedemicro.com>
    >
    > Most alternate engine installations added a substantial amount of
   weight
    > to the airframe. Original designed empty weight was 350 lb. There are
    > many flying BD-5s that almost DOUBLE the original weight
   estimate. The
    > Honda EB3 installation, one of the more successful substitute engine
    > packages, puts out 110 hp but tips the scale at 137 lb. with
   turbo, rad
    > and fluids.
    > My BD-5 uses a Honda but I'd like to convert to a rotary. A 2
   rotor of
    > 100hp weighing around 100 lb. would, IMHO, make an ideal package.
    > John Lewis
    > N501BD
    >
   John,

   The new Rotary Aircraft Engines Skypower 65 (single rotor) version of
   Rotamax comes close to your ideal.

   http://www.rotaryaircraftengines.com/enginemodels.htm


   "Rotamax Skypower 65 Aviation Engine - Ultralight Market
   Max Horsepower         Cruise Horsepower        Fuel Burn
   65 hp @ 6,500 rpm       55 hp @ 5,500 rpm       2.2 - 3.1 gph


   Weight          Price w/Gear PSRU       Overnight Rebuild
   110 lbs         $7,995  $2,495

   New dual spark, dual ignition, carbureted and water cooled aviation
   engine.
   This engine produces as much horsepower as a 2 piston two stroke
   Rotax 582.
   Its TBO is 500 hours, 200 more than the 582. But it has several
   hundred fewer
   parts to wear out, or fail, or need replacement, and it does not
   vibrate. Buy
   it for four-stroke reliability, no vibration, regular gas fuel
   economy, low
   emissions, and extended life span. You will realize a much lower
   total cost
   of ownership. ASTM compliance testing is under way and will be
   completed by
   about May 15, 2008."

   The 110 lb weight includes 20 lbs. for the PSRU.  You can figure the
   tradeoff vs.
   the BD-5 belt reduction.  In December I had an email exchange with
   Nate Oldham
   at RAE, and he said the turbo charged version of the 65 puts out 100
   hp and the
   turbo adds 12 lbs.  So without the PSRU and with the turbo, you have
   100 hp at
   102 lbs.  :-)    Those weights at the time did not include the
   radiator, hoses
   and coolant, and I suspect they still don't.  The Hornet info should
   be able
   to add some detail to total weight.

   Joe Cook  (considering the Skypower 65 for my Sky Raider 1 to replace
   the Rotax 503 and ex-owner of a BD-5 kit long ago.)


Morning Joe,
Thanks for the RAE info. I've been looking at them too. Wish I had the
$$$ to convert but will have to stick with my EB3 for now.
John

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