John Gibbons wrote:

Paul and all,

    I was discussing the new diesel that Diamond has on its new twin. If they come close to what
they claim, it looks like they will have a good engine ( not as good as a wankel of course !!! ).
The idea of diesel seems to offer some very good benefits, particularly in regard to cheap and
available fuel, simplicity and safety. I started to wonder about the possibilities of dieselising
a Mazda. I figure the weak point would be the apex seals and possibly the side seals. Paul you
just said yesterday that the engine itself is almost bullet proof. What is the lowest compression
ratio you could use with diesel and how could that be accomplished in a rotary ? Some of it could
be blown in but I would think you would still need to increase the CR for start up and idle before
your turbo or supercharger start to work. How is the CR changed between the NA and turbo Mazda's
?

Thanks,

John

That is the A class Mercedes econo box engine. There is some doubt the FAA is going
to certify  that. If they certify that they will have to approve the Mecanair
Mazda rotary. Forget the true diesel cycle for a rotary. Won't happen.
The combustion chamber shape would be so thin as to be unworkable. It will
run on direct injected spark assisted diesel fuel however.

It would be better to do a turbo compound rotary and enjoy the same low fuel
burn characteristics of a true diesel.

All the current hype on aircraft diesels applies to Europe where diesel fuel is half 
the cost of gasoline due to the silly commie tax policy. (Tax the hell out of
the poor dumb suckers till they quit working :)) An aircraft diesel engine 
is not worth the extra weight in the USA. At best the fuel burn reduction 
at aircraft power levels is only 15 to 20%. Not worth the stink, noise 
and weight. On the other hand if you have a source for 80 cents a gallon 
farm diesel fuel... go for it :)

Paul Lamar
 
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