Paul, here's an idea for you to ponder if we are looking for the
    lowest BSFC.

    When reading your description of the operation of the TTC project
    one item should stand out.

    That keyword is "waste".

    The waste gate and the fixed orifice bleed that you are using are
    all lost energy!

    The ideal scenario would be to capture all of this energy and reuse
    it in the engine itself.

    A compound turbo is one solution but it's redrive is complex, takes
    up space, and is extra weight.

    Now imagine if we could do all of this recapturing  with existing
    components and no extra weight!

    We would do this by forcing all of the produced compressed air to go

    through the engine.

    This would be accomplished by not fueling strategic combinations of
    combustion cycles of both rotors in order to control the output of
    the turbo...... or "EGT Boost Control"

    Actually engine weight would go down because we wouldn't be using
    the wastegate and a portion of the exhaust manifold.

    The computer logic would sound something like..... when the boost
    pressure gets to x psi,

    1- we would skip fire the injector on the rotor with the highest
    EGT.

    2- if pressure needs further adjustment we would skip fire both
    rotors.

    Both of these scenarios would cool exhaust gases thereby controlling
    the boost pressure... but using all of the turbos available energy.


    Barry Bordes


    It would sound like it was missing (it is) and severe shake or low
    frequency vibration would set it :-)


    Paul Lamar

    It would probably sound different when in overboost control mode but
    I believe it would be smooth. Four strokes skip ever other firing but
    they do sound different than a two-stroke..... but with no vibration
    problem. It would probably sound like F1 engines in pit lane speed
    control mode. They random fire the engines with no obvious ill
    effects.

    Barry Bordes

    Duty cycle. The F1 engines use a pitlane speed control that works the
    same as rev limiter that cuts the ignition. They do that so cylinders
    do not go lean and fry a piston or valve. The engines runs that way
    for a few seconds. In an aircraft it could run that way for hours at
    a time. I think the prop blades would fatigue and fly apart.

    Dale Davies




   There would be a difference in vibration and only test we confirm if they are acceptable.

   Norton use a similar process on the road racing rotaries. They would have one rotor shut down so the other road or would pull more cleanly for the next acceleration sequence. Since the throttles we're open more pumping losses go down.

   GM use it on their 468 cylinder shutdown procedure for fuel economy.
   GM also used it as a limp mode if an engine overheated ...they would sequentially cool cylinders with airflow but no ignition.

   Because the throttles would be more opened in this cruise condition the BFSC on the rotary would also be decreased by the reduction of pumping losses.

   And the beauty of a peripheral port engine is that since it never closes the rotor acts like a water wheel with the boost spending it... in essence acting like a power recovery turbine!

   There seems to be a lot of positives for an aircraft configuration compared to the negatives.

   The AR for the turbine housing should also be matched better. It would be divided and probably something between 1.5 and 2.0 instead of .8 to .9AR.

   Cordially,
   Barry Bordes


   I have heard a two rotor run with one rotor off. Runs like crap. It will get you to an airfield  probably.

   "road or would pull more cleanly for the next acceleration sequence."

   What the hell does that mean? Sounds like bullshit to me Barry :-)

   It does not matter if the second intake port is open or not. It will still take
   torque to compress the air in there.

   Paul Lamar

Has anyone tried water injection into the exhaust? Use the heat to flash water to steam and create a little thrust. With creative plumbing and good pipe orientation to the rear, it might work as a power recovery jet (afterburner, of sorts) and cool the exhaust as well? I suppose it could create a lot of back pressure... Maybe time the injection in harmony with rotor position--a tuned, super exhaust.
Lewis Bjork


I don't think anybody has tried but that is a good idea.
Especially for something like a record speed or time to climb.

Paul Lamar

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