In article ,
ost (Chris Mark) writes:
From: Guy Alcala

in 1941,
they started to see just how much they could safely stretch the fuel economy
of the Zero, individually and then in larger groups. Ten hour missions
became routine, then 11 and eventually they were able to stay in the air for
12. Okumiya describes this in "Zero!", with average fuel consumption
dropping to 21 gal./hr. and Saburo Sakai holding the record at only 18
gal./hr.

Interesting. The Wright R-2600 engine burned about 75gph at 60 percent power.
Any details on how the Japanese achieved such frugal fuel consumption figures?
What was "normal" fuel consumption for the Zero?

They did it the classical way - Minimum RPM, Maximum Manifold Pressure
to maintain that RPM, as lean a mixture as the engine can stand, and
flying at the altitude where, with those conditions, they could
maintain the minimum drag spot on the airplane's drag curve. (Probably
around 15,000', in a Zero, maybe a bit lower.)
You can turn in some really impressive fuel burn numbers that way.
The low RPM means that the total volume of fuel/air mixture per unit
of time is as small as it can get. The High Manifold Pressure means
that you're getting the most out of that small volume.

Note that you can't do this unless you've got a fully controllable or
Constant Speed prop.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster