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

 If I was to "Hazard" a guess I would say safety is the reason.
 Try and imaging what a back fire would be like into a fuel/air
 charged intake manifold! Yikes.

 Erik


 A back fire is highly unlikely as it would have to flow
 up stream against positive pressure. I have never heard
 of a Merlin or Allison back fire through the compressor.
 The term is frequently misused to describe explosions
 in the exhaust manifold.

 Paul Lamar
 --
   Hi, not all turbos have shaft seals that can handle vacuum, efi set ups
 have the throttle on the discharge side of the compressor and often a blow
 off or by pass valve for to dump pressure spikes on sudden throttle
 closures.  Some have better seals to keep the oil from getting sucked out
 and the throttle can be used on either side of the compressor.  Not sure
 about the Aerocharger.  The big engines often had carbs on the supercharger
 inlet.  The cooling from the evaporating fuel improved the supercharger
 system efficiency and helped make the mixture more uniform in the complex
 manifold. Some had the fuel dischage from the eye of the compressor.   The
 Merlin had flame traps, honeycomb inserts at the intake ports to stop
 backfires from getting into the manifold.  Not sure about other engines.
 Turbo engines love water injection.

 Murry


 "Bearing Design & Lubrication
 A unique self-contained oil system was also created for the Aerocharger®
 which
 lubricates the ball bearings in a fine mist of oil. Since the oiling
 system is
 separate from the engine, a proper lubricant can be used for the precision
 ball
 bearings instead of using oil formulated for engines. This differs from
 conventional turbochargers that use a flooded bearing system which rely
 upon
 the engine?s lubrication system. By avoiding the use of a flooded design a
 virtually frictionless, self-contained bearing lubrication system was
 achieved."



 "Conventional turbochargers use a flooded journal or ball type bearing
 centered
 between the turbine and compressor housings. This bearing assembly is
 plumbed
 into the engines lubrication system where hot motor oil is constantly
 pumped
 through it. In many cases, particularly production turbocharged engines,
 this
 bearing assembly has separate cavities for the engine?s coolant to flow
 through
 to aid in cooling the bearing as well. "

 http://www.aerocharger.com/**technology.php#Bearing<http://www.aerocharger.com/technology.php#Bearing


Ed
I have one other thought about fuel injection into the Aerocharger intake
chamber, I used to encounter what we termed "etching" on the impeller
caused by chemical and droplets hitting the vanes.  Now this was in
oilfield applications, we ran a cyclone to separate liquids and gas from
the oil well production stream.  The gas portion of that was compressed,
then flowed to storage tanks for treatment.

Our experience is that small droplets sometimes got into the compressor,
and struck the vanes causing etching, of coarse some amount of the damage
was due to corrosive chemicals in the gas production of a given oil well.

At the speeds the impeller will be spinning I think you can consider some
damage from your fuel injection as a given.  Perhaps you can figure some
barrier/method that will divert the full impact of droplets from the
injectors.  I make the assumption that not all of the injected fuel will be
vaporized, and hoping that the surface of the vanes are of a quality to
take the impact force.

GFCurtis Jr.

Randy Lewis has his carb bolted to the turbo intake.
Are you seeing any erosion Randy?

Paul Lamar