Martin,
    > I'm working on a single rotor development for my aircraft using 12A
    > housings
    > with early 13B rotor housing and a RX8 rotor with apex seals cut
   to 3mm.
    >
    > I don't have the problem of balancing the rocking couple, so the
   balance
    > of
    > the single rotor should be close to static balance.
    >
    > Advice to me with balancing is to consider full rotor oil weight
   as well
    > as
    > all seals except the apex seal and add this to the rotor weight.
   Not to
    > include the apex seal and springs as their carried by the rotor
   housing.
    >
    > Can you comment on this in regard to balancing the single rotor,
   I would
    > like to get it right the first time, if at all possible, as the
   single
    > has
    > the big torque reversals, so is not as smooth as the 2 rotor.
    > George (down under)
    >
    >
    > George,
    >
    > I have been working on single rotor engines for more than ten years -
    > including their balancing. So I am fully aware of their potential
    > problems with torsional vibrations. At MWE/Diamond for instance
   it was a
    > set rule not to run the engines below 2,500 rpm, preferably 3,000 rpm
    > plus. We had more than a couple of dyno couplings literally explode
    > within seconds when engines were run at low speeds and high loads!
    >
    > The assumption to add the inner rotor volume of oil was one of the
    > points discussed more than once. All plain bearing engines I had
   built
    > at WankelSuperTec had been balanced outside the company based on the
    > aforementioned assumption. They ran quite smooth taking into account
    > their high compression ratio and the very crude mapping those early
    > days.
    >
    > The MWE/Diamond rotors are fresh air cooled by a blower fan
   though. So
    > apparently there is no oil in the rotors. But we had the permanent
    > discussion of whether to include the weight of the apex seals and
   their
    > springs when being balanced. The designers and calculators said:
    > NO, the apex seals are not part of the rotating assembly as they
   "rest"
    > on the rotor housing.
    > BUT test comparisons carried out at Norton in the 1980s showed that
    > engines, balanced WITH the additional weight of the apex seals and
    > springs, ran smoother still than those without! Theory behind it was
    > that the inertia of those seals and springs is still imposed on the
    > outer structure of the engine, hence the frame as well.
    >
    > If I remember correctly the total weight of a set of apex seals and
    > springs of a Diamond single rotor engine is in the order of
   30gramms. A
    > Mazda set weighs a lot more still.
    >
    > To sum it up in one sentence: If I was to balance a Mazda Single
   Rotor
    > engine I would add the weight of all seals and springs and the
   weight of
    > the oil as well. Hope you get it right that way!
    >
    > One question with regards to your set-up: Why will you be using
   an RX8
    > rotor in an RX7 rotor housing? What benefit are you expecting
   form that
    > mix?
    >
    > Regards and good luck,
    >
    > Martin.
    >
    > George,

Look at Mazda Motorsports page under "Balancing"

http://www.mazdamotorsports.com/webapp/wcs/stores/servlet/Tech?

Use Google MSIE can't find it???

Lynn E. Hanover


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