6 stroke engine
fmarino1976 said:
Thanks for taking the time to explain the Beare cycle engine. Now, assuming 2 similar engines, one with a conventional valve arrangement and the other one with a beare head, what kind of efficiency gain can be expected? Would fuel consumption be similar? Thanks again.
This is what can be achieved in the fuel economy stakes on an early prototype a Yamaha TT 500 conversion. same port area same compression ratio, cranking pressure 135PSI for both engines.
FUEL CONSUMPTION TEST
ROAD SPEED MPH 4STROKE RUN TIME SECONDS 100cc FUEL 6STROKE RUN TIME SECONDS
100cc FUEL LOADED RPM
In 5th GEAR % LONGER RUN TIME
30 MPH 4ST 159 sec 6ST 216 sec 2000 RPM 35.8%
35 MPH 4ST 138 sec 6ST 184 sec 2500 RPM 33%
40 MPH 4ST 107 sec 6ST 134 sec 3000 RPM 25.2%
45 MPH 4ST 89 sec 6ST 101 sec 3500 RPM 13%
YAMAHA TT 500cc
Test by Malcolm Beare, Elliot Munro, Grant Guy, July 1995
The dyno used was an old motorbike dyno with the rear wheel driving a large fan with a speed readout dial. The throttle was opend enough to maintain the designated speed. So the power outputs were identicle
The sixstroke head was designed to as closely match the fourstroke as possible compression ratio , valve timing , port sizes. Not a fully optimised sixstroke much more port area is available.
and compression ratio could be higher.
The sixstroke would run happily at lower revs(1000) than the fourstroke in 5th gear. The fourstroke would pull 4000 RPM at full throttle the sixstroke 3500.
Same gearing same carburetor.
Fuel was gravity fed to the carb from a long clear tube with two level marks to indicate 100cc.
Harvey said:
Hi Mal,
It has been some years since we spoke, and I saw your bike run. That was around the time Sir Alan Cathcart rode it, so wondering what has happened in the meantime. I gather you also have some aviation interest ?
Cheers
Martin Hone
ex-AMCN
http://www.sixstroke.com/truth.htm
this is my personal oppinion based on my experience
I resigned as a director of Jack Brabham Engines Ltd when it became obvious that the MD APC was utilising shareholders funds inappropriately.