This is a rotary engine program I am now working on. I am the resident
engineer on this project.
Several years ago an American rotor head by the name of Russ McFarland
living New Castle Australia decided to sponsor a Mazda rotary powered
world record attempt time to climb aircraft. Russ was a long time
subscriber to the Rotary Engine News Letter.
Russ decided to use a 650 HP turbo charged Mazda 13B all aluminum engine.
Russ contacted the same gentlemen that built Dave Garber's engines back
in 1973. Namely Jim Mederer owner of Racing Beat in Southern CA. BTW Jim
holds the stock car body land speed record at Bonneville at 268 MPH in
an Mazda RX7. Stock body means you cannot improve the aerodynamics of
the car bought off the show room floor.
Russ was counting on the high power to weight ratio of the Wankel and
it's exceptionable robust nature. This 13B TC engine weighed less than
200 pounds with the turbo.
The projected life of the silicon nitride ceramic apex seals is now
20,000 hours in the Mazda chrome plated steel lined rotor housings.
The propeller driven absolute time to climb records is 90 seconds from a
dead stop on the runway to 3000 meters I believe it is held by a Grumman
Bearcat. This is not a weight class record. This is an absolute world
record. If this works the turbo Wankel will go down in history as
another type of viable aircraft engine. Joining piston engines, turbo
props and pure Jets.
This time Jim was able to extract 650 HP running on methanol. Jim also
developed aluminum end housings that dropped the engine weight
from about 300 pounds to 200 pounds. Jim designed and had cast aluminum
housing to replace the three cast iron housings.
Lots of other engine changes were made. A dry sump oil system was needed
so the oil pan was done away with and replaced with AN pluming that
extracted oil directly from the center, front and rear end housings and
send it to the oil cooler. A new larger capacity water pump was needed.
A p-port was chosen instead of the stock side ports.
A Motec after market EFI system was chosen to supply fuel to the engine.
That came with an EFIS. The rotors are modified stock rotors as is the
eccentric shaft. A capacitor discharge ignition system is used.
Historically this development is on a par with the jet engine and the
turbo prop engine on a power to weight basis.
Not only will it best a PT6 turbo prop on power to weight ratio but it
will burn half the fuel.
Now for the chosen aircraft to accept this engine.
A flying Harmon Rocket was purchased and the Lycoming engine and
instruments were removed and sold.
Russ choose the same gear box that Dave Garber used and flew. In fact he
obtained one of Dave's gear boxes from his widow.
Namely a Bell 47 helicopter 3:1 final drive. Russ choose Dan Gray from
Santa Paula California to complete the installation.
I designed the liquid cooling system. It was a real challenge so I
choose two large Dodge truck radiators and TIG welded them back to back
in what is known as a cross counter flow configuration. This is
outlined in the Kays & London book "Compact Heat Exchangers".
I am also the author of a book called "How To Cool Your Wankel".
Cold water will be sprayed on this radiator as needed in the evaporation
cooling mode. After testing the coolant never got
hotter than 120 F. See the attached logged data from the Motec.
The water spray was never needed.
The pilot was moved to the back seat and the 20 gallon alcohol fuel, 10
gallon water and 4 gallon oil tanks were installed behind the stock
firewall. Water injection is used to cool the intake air at high
manifold pressures. Moving the pilot was necessary as the original six
cyl 300 HP Lyc AC engine weighed over 550 pounds. The Mazda with gear
box, fire wall forward, was 300 pounds. Initially we had a rear CG
problem. That is the reason for no tail wheel :-).
A new carbon fiber instrument panel with altimeter, air speed and EFIS
screen was installed.
The power to weight ratio of the Bearcat was approximately 2 pounds per
HP. The power to weight ratio of this aircraft is only 1.5 pound per HP.
We estimate the Mazda powered Harmon Rocket will climb vertically at
175 MPH based on the exceptional power to weight ratio. This should
easily break the 91 second TTC record.
We test flew the aircraft for ten minutes at California City in the
desert several weeks ago and got it up to 8000 feet. Here is a video
of the take off.
We were fine tuning the Motec EFI last Friday at SZP and it is nearly
ready to attempt the record. It will be done at SZP as the altitude is
only 245 feet above sea level.
Paul Lamar
Paul,
Great write up, thank you.
The picture of Dan putting the prop on is great, it really shows off the
size and power in that engine.
Could you elaborate a bit on your comment about the rotor and eshaft
modifications please.
John Rogi
Yes indeed. That picture was a stroke of luck :-)
Thanks
Paul Lamar
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