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 carburetted 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