Jim Mederer used a interesting technique to tune the turbo for
        aircraft use. Most turbos are designed for automotive use where
        fast spool up is necessary. The probelm with this is at high
        continuous aircraft power the turbine will over heat and or over
        speed and fail.

        What Jim did was use a controlled leak in the exhaust manifold to
        get just enough boost.

        Works better than a waste gate with low A/R turbos.

        This has a side benefit of reducing the exhaust back pressure. Less
        back pressure more power.

        Paul Lamar

        Hi Paul. I don’t understand! I thought a waist gate was a controlled
        leak in the exhaust manifold.

        Steve Izett

       Yes it is but it is a bit heavy and problematic.
       This  is much simpler and and lighter weight.

       The waste gate only measures the back pressure.
       This device respons to the ratio of back pressure to atmosperica pressure.
       I think it does a better job of keeping the HP matched to the altitude change.

       Of course the jury is still out until we fly it.



       Paul Lamar





       Paul,
          Is the rectangular tube in photos the "Controlled Exhaust Leak" ??................


        Kelly Troyer

   Yes but it is but not that big. Up stream of that there is a one inch orifice.
   To get more boost you go to 3/4 inch. Less boost 1.5 inch.
   Simple, cheap and it works great.

   A waste gate gives you more boost at low RPM. Not what you
   need in an aircraft engine.


   Paul Lamar

Paul, I like the pictures. sturdy reduction drive! what is the ratio. what would it take to get two of them?

james whitehurst

Those are Bell 47 helicopter final drives at $35,000 apiece.
We did not pay that much as we inherited it from Dave Garber.

I am working on a much cheaper version using Allison truck transmission
parts.  We are thinking of a turbo 3 rotor powered Lancair for the Sports
Class at Reno. We need to come up with 200K $$$$$

Paul Lamar

   The Rotary Engine News Letter. Powered by Linux.
   If you want off the list PLEASE let me know and I will
   remove  you.  ACRE NL web site. http://www.rotaryeng.net
   You Tube http://tinyurl.com/beqqxas
   Copyright 1998-2016 All world wide rights reserved.