http://www.aerocharger.com

  Ed Carver  brought by his Aerocharger on a recent visit to
  the hangar.

  Somehow I missed the fact all these years that is was a variable
  vane turbo. Apparently a well kept secret in the turbo charger world.
  How I missed this fact I will never know. Perhaps they have good
patents
  and nobody wants to talk it up. If it works as claimed it will put
  all the other turbo guys out of biz.

  This unit is ideal for turbo charging an aircraft
  engine as you can slow the prop RPM with higher prop pitch
  and boost the HP at that RPM with the variable vanes.

  It is also ideal for turbo compound.

  The convoluted design of the turbine housing leads to a cooler
  exhaust impinging on the vanes and the turbine wheel. The bearing
  oil supply is also self contained. No engine oil required. One could
  probably use turbine oil and have a separate oil cooler system if
 necessary.

  This is a very innovated unit indeed.

  "VATN is a series of variable-vanes that optimize the flow area of
  the turbine by adapting to the exhaust gases. By doing this, the
  turbine wheel is able to operate at peak efficiency throughout a
  wide RPM range, something that has never been achieved before. This
  also eliminates the need for a wastegate, which conventional
  turbochargers rely upon to control boost. Instead, the vanes
  automatically adjust the flow area and backpressure to perfectly
  match the torque requirements of the compressor wheel to produce the
  desired boost. Eliminating the need for a wastgate means eliminating
  extra cost in your turbo system"

  Paul Lamar

  Hi Paul

  I have been very interested in the bearing assembly and lubrication
setup
  on the cool side.

  Cheers

  Steve Izett

  Paul,
  What series "Aerocharger" does Ed Carver have and what is the
compressor
  trim.......Also does anyone know
  if the "Aerocharger" turbine wheel and varible vane system will live
  under the Rotary's hot (up to 1800 f) breath ?

  Kelly Troyer

  I'm hoping someone actually knows about the temp limits of the
  vanes. The whole aerocharger design has heat control in mind. The
  turbine scroll has a coating on the iron, or so it appears. The
  exhaust heat is never focused on one area as is the case in a
  regular turbo. The design spreads the heat around a far larger area
  and keeps the pressures much lower at any given point. My intent in
  purchasing and using this is not to get high boost, but simply to
  maintain the minimum power necessary to stay at cruise speed up to
  17 to 18k feet, which should be much less than 150hp for a cozy 4.
  Because I am using P ports, my base hp is near 250hp. I believe I
  have read that there are some cozy 4 flying with 150hp rated o-320s
  in them and do quite well.

  The point is, I don't really need 200+hp, and therefor, the heat factor
  will not be at max temp for long durations. I could never use the
  max power generated from my turbocharged p ported rotary; so I am
  building for efficiency, and aerocharger has some very favorable
  design features.
  a. No oil lines to feed it.
  b. No waste gate.
  c. No hot side shaft seals to blow, therefor, no oil loss.
  d. Designed turbine speed gets the work done below 90krpm
  e. High exhaust throughput (low restriction) when the vanes are in
  the open position.
  f. Manual boost control by adjusting vane angle using the control
shaft.
  g. Relatively simple exhaust tubing.
  h. Can be mounted in many different positions.

  Will the vanes hold up?
  They probably will.
  We shall test it at operating power to see.
  I can hardly wait!
  But that's my feeling about the whole project.
  Really though, I can't tell if the thing will work for 5 min. until
  I try.

  Regarding the question about which model I have?; "it's the big
  one". They sell two sizes, and set them up for different
  applications. I hav'nt measured the turbine size since last Jan. so
  I don't remember which one I have.

  Ed Carver

  Ed,
  Did you purchase your turbo direct from "Aerocharger" and if so did
they
  know it
  was destined for use with a Rotary engine (no mention of aircraft of
  course) ?...........

  In doing quick scan of  their site I could find no mention of any
Rotary
  conversions
  using the "Aerocharger"......There was mention of Diesels having used
  variable
  vane Turbo's but only in gas engines in the last few years because
  of the the extra exhaust heat (200 f +) above a diesel.......Our
  Rotaries then can produce another 200 f (+ or -) above
  that.....Would be interesting to hear what the "Aerocharger" have to
  say on this subject.....IMHO

  Kelly Troyer

  The exhaust temp on an RX8 side exhaust port engine is 200 F cooler.
  Ed is using an RX8 engine as I recall.

  Paul Lamar

  Kelly,

  Actually, if you look @ the military applications listed on the
 aerocharger
  site, they talk about their turbo's being used on rotary powered
  UAV's giving them a 50% increase in power @ 2.5lbs of boost...

  -Dan Gorsline

  --

  The aerocharger is very obviously designed to control heat coming
  from the hot gasses that pass through it. They want these things to
  live long lives. When you take one apart as I did, it's easy to see.
  The one truly bizarre element of it is how close the compressor is
  to the turbine wheel. This point alone helps cool the turbine, at
  the price of heating the intake air.

  I plan to inject fuel directly into the compressor inlet, hoping to
avoid
  the use of an intercooler. The very rapid vaporization of the fuel
should
  give the compressor a good chill. I'm also going to try to keep the
entire
  intake system on the intake side of the engine, to avoid long runs
  of tube which will tend to bog the whole system down.

  When I purchased this thing, I knew it may well melt, in which case,
  I take it to the rebuilder, and have the inconel turbine recast.
  Then make some solid inconel vanes to replace the originals. I won't
  be out much if it breaks.

  On the other hand, when I test, it will be under MY intended use
  loads. I have no reason to find what it takes to fail it, but only
  to know if it will work for me. Given the thin material the vanes
  are made from, I should know what I want to know within an hour or
  so of a test run.

  And yes, the rx8 engine will get this unit.

  Murry, I did'nt see ya at the last eaa meetn. Hopfully next, we can
grind
  on this subject for a while.

  There should not be any excess boost using this turbo in my install.
  It is purely for high altitude flight using the minimum power it
  takes to maintain cruise speed. What I think will happen is on take
  off there will be no boost, the vanes will be adjusted to prevent
  it. Then as altitude increases, vane angle is adjusted to increase
  turbine speed thereby maintaining the necessary intake pressure to
  hold minimum required cruise power at the chosen altitude.

  Realistically idealistic?

  Ed Carver

  Ed , Paul and all,

        I know that you do not see very many Turbo systems injecting
  fuel directly into the Turbo compressor inlet...........Is there a
  reason for this ?...........Is there a possibility of compressor
  blade erosion over the long term ??...........

  Kelly Troyer

  It was done that way in WW II.

  Paul Lamar


  It is like a carburettor suck through system. The EFI will produce
smaller
 droplet size than a carb will, with better fuel metering. A throttle
body
 injector from a 454 Chev would work well. Just needs carb heat system
as it
 can freeze up also.


 Dale Davies


Another thing about back fires, they are usually caused by an excessively
rich mix, and that caused by poor cold start controlling. I will also be
using the stock rx8 injectors for low speed/idle mixture, and keep them
closer to the intake port. That way fires can't travel far into the
incoming dry air. The stock injectors produce a very fine mist.

Ed Carver



 Re Backfires in the inlet,  I beg to differ on the cause, it almost
always happens because the mixture is too LEAN, so is burning slowly
usually running around the combustion chamber and when the inlet valve
opens, the flame gets sucked out into the inlet manifold, very sad for
the choke plate on a Holley carby, usually puts a big bend in it,(the
choke is usually pulled on), if not straightened, causes high fuel
useage because it covers up the air bleed jet from air flow.
              John Burey