I added a few detail pictures to Randy's collection
on his one rotor powered DragonFly.

It has a very interesting idea in that the Ellison carb
is mounted directly on the intake side of the turbo charger.
A very compact way to handle the intake system.
The turbo charger is not Mazda so it might be large
enough to live with a one rotor. I suggested a
Garrett turbo charger tachometer kit to keep an
eye on the turbine RPM.

All and all a pretty good installation job with the
possible exception of the motor mount. The belt drive
also needs a few improvements to the torsional
stiffness. A minor thing to improve.

We were not able to identify the ignition system yet
but it looks pretty straight forward using what
appears to be an early Mazda magnetic crank angle sensor
distributor. I think the coils came from Ellison but
I am not sure about that.

The water pump housing is custom but I do not
recognize the cartridge. It is from something
other than a Mazda. The two oil coolers are a needless
complication when one larger one will do. One of the
oil coolers is in the vicinity of the sharp exhaust pipe
bend so the bend radius would benefit from the removal of
that oil cooler.

I suggest something from the Setrab catalog pdf attached.

If the turbo charger could be rotated
180 degrees that would put the exhaust in the rear and
the carb in front which would benefit both.

All of the cooling openings need the application
of Kays and London's or Kuchemann and Weber diffusers.
The water cooler is the quick and simple type under the
fuse behind the cockpit which is very good way to go on
this airplane as it has limited volume under the cowl.

There is nothing really wrong with it and I think it will
fly as is. Keeping the turbo charger would make it a great
cross country aircraft as speed up high would be spectacular
for a such an aircraft. It would probably be the only
turbo charged DragonFly in the world.

Ed Carver and I were trying to talk Randy into keeping
the rotary :)

Paul Lamar

 Paul,

 Any speculation as to the HP the system would produce?
 If one installed a compound turbo would two tachometers be needed on the
 compound turbines respectively?

 Thanks,
 Gordon

 Somewhere between 100 HP and 225 HP depending on the boost :)
 Actually anything over about 150 HP would require the addition
 of an intercooler. Maybe as little as 125 HP. One would
 have to monitor the intake air temperature and keep it below
 140 F.

 I would think so on the series turbo chargers. Are you looking to
 set an altitude record :) You are not thinking of using the boat
 anchor 3rd gen RX7 sequential turbo charger setup are you?
 That thing is probably close to 40 pounds while a TO4 is 16 pounds.

 Paul Lamar
 --
In spite of our economy I still have hopes that some able bodied soul
will step forward and work with you and generate a compound turbo.
[turbo compound?] I am
convinced that a turbo charger, as it gets one off the ground in a
hurry, adds a dimension of safety to flying.  The other arguments for a
compound turbo have been well established.

My questions were born more of curiosity than anything else.  I still
want to construct a Christivia IV with a "full size" engine, but at one
time had my eye on a Hummelbird
http://www.flyhummel.com/hummel_bird.htm.  With the 1/2 Volkswagon
engine, however, I could never justify the attempt. A one rotor
similar to the one used in the the dragonfly would probably work in a
Hummelbird.  Of some note there is a small aircraft that is modeled
after the Hummel and will accommodate someone my weight and size.  It is
the BK-1.  While the designer uses a Full Size VW engine, I believe it
would be vastly improved with a rotary.  The website for this plane is
( http://www.bkfliers.com/).  I also had a love affair with the Mini-Imp
(http://www.mini-imp.com/) and am convinced that a single rotor engine
would work well.  Once again, I am too large for the IMP.  If one weighs
over 170lbs, according to the current Mini-Imp entrepreneur, you can
forget it.

Regards,
Gordon

I think what you mean is turbo compound and not compound turbo.
Different things.

The one rotor Mazda engine is more expensive than a 2 rotor
so the best thing to do is find an airplane design or kit large
enough to accommodate 300 pounds fire wall forward rather than
200 pounds fire wall forward.

The one rotor fire wall forward can be made to weigh less
than 200 pound but it requires aluminum end housings. That
adds about $3000 to the cost of the engine. Given the cost
of the PSRU and the intake system and a rotary overhaul you are
looking at about $10,000 for the engine. Of course you can
overhaul the rotary yourself and save $2,000.

New O-200's are about $20K. Same for a Rotax 912.
A clapped out C150 with an O-200 go for $10,000 to $12,000
If you have to overhaul the O-200 that cost about $10,000.

The cost advantage to any experimental over a C150 is the fact
that you don't need an annual done by an IA that charges
$500 for his signature alone not including the price of
certified parts and actual labor of doing the annual.
There is always work to be done on a used certified airplane.

The real hidden advantage to a rotary powered experimental
airplane is when it comes  to overhaul time. You can do
it your self or get it done for $3,000. Of course rotaries
rarely need overhaul but we do not have enough flying to
come up with a accurate TBO number. My guess is 3000 hours.

The large Ingersoll Rand Wankel rotary engine set a world
record at 41,000 hours. Ceramic apex seals are projected
to last 30,000 hours. There are no mechanical parts in
a rotary that are subject to metal fatigue. Certain little
rotary engine tricks that are known to reduce wear are not
yet applied. One of those is using chrome plated apex
seal slots or chrome plated end housings. Another is just DLC
coatings on end housings. Mazda is already using DLC coatings
on the corner seal of a stock RX8 engine.

The rotary liquid cooling system does require regular maintenance.

The next thing is the cost of fuel. Most people put on
50 hours a year. At 10 gallons an hour that 500 gallons a year.
At the current $4 a gallon for 100 LL that is $2000 right
there. The rotary will burn car gas at $3 a gallon so
there is $500 savings there.

Total savings is about $1000 annually.

Just about any rotary powered airplane can cruise
at 150 MPH. Many more at 175 MPH. Some over 200 MPH.
The C150 is lucky to make 100 MPH. In effect that adds
to the savings as you burn less fuel getting where you
are going. If you have a head wind the savings increase.

IMHO that makes a 100 MPH airplane a toy in the U.S. and not
useful as a real airplane. In certain areas of the
world like the Oz outback, maybe Africa  and Alaska that
does not matter as any airplane, no matter how slow, is
the only practical way of getting there. I have personal
experience on that matter.

Paul Lamar