"Jim Carriere" wrote in message
...
Ben Hallert wrote:
Howdy,

Just for comparison, the O-200 puts out 100hp at like 5-6gph of av gas,
right? Whether or not the engine mentioned can do it, it seems
difficult to believe that the O-200 is the height of efficiency. 100hp
at 4gph doesn't seem like that far of a stretch when compared to the
burn on the O-200, I guess, especially when energy denser fuels than
avgas exist.

That said, I don't understand what the bourke engine is supposed to do
different to get the numbers it describes, like another poster
mentioned, it looks like a two cylinder rotary.

Most internal combustion engines (including the O-200) have a BSFC
between 0.4 and 0.5 pounds/hp/hour.

I'd say an O-200 puts out 100hp at about 8gph, 5-6 gph is a typical
cruise fuel flow. 100hp is at sea level, wide open throttle, max rpm.
You don't spend too much flight time in that regime.

The O-200 is not the height of efficiency, but it isn't the height of
inefficiency either. From an engineering perspective, 0.25 lb/hp/hr is,
uh, extraordinary to say the least. Think of it like the internal
combustion engine's answer to cold fusion.

Yup. The gigiantic Sulzer marine diesels only get 0.278 lbs per hp per hour
on heavy bunker oil. That's about as good as it gets. Of course that's
1660 GPH for 108,920 hp and 5,608,312 lb/ft of torque at 102 rpm for the
I-14. Oh yes, no PSRU, the propeller is direct drive.

See: http://www.bath.ac.uk/~ccsshb/12cyl/

Bill Daniels