With improved aerodynamics, 1930s’ fighter airframes needed more powerful, reliable engines
to optimize their combat potential. Families of
1,000hp engines emerged during the decade,
including Allisons and Pratt & Whitneys in the
United States, Rolls-Royce in Britain, and Daimler-Benz in Germany. France and Italy lagged in
engine development, while Russia and Japan
played catch-up. Liquid-cooled in-line power-
1930 | Enclosed Cockpits
Increasing altitude performance
required better protection for aircrew from the freezing atmosphere
three miles high. Though many
WW II aircraft still possessed inadequate cockpit heating, the combination of an enclosed cabin and
reliable oxygen systems meant vastly
improved physiological conditions
and greater operational capability.
In turn, jet fighters routinely flying
above 40,000 feet led to pressurized cockpits for
comfort and survivability.
Closely related to enclosed cockpits was can-
opy design, with all-round vision “bubble” ver-
sions common by war’s end. Evolution continued
into the jet age with the world standard becom-
ing a 360-degree configuration by the 1970s.
“First sight, win the fight” was a mantra based on
combat experience with improved visibility from
bubble versus faired-in canopies.
plants were most common owing to a more
streamlined frontal area than air-cooled radials,
translating into greater maximum speed. By the
early 1940s, however, 2,000hp Pratt & Whitneys
and Germany’s 1,700hp BMWs were competitive
with the V-configuration engines. At war’s end,
most piston-engine fighters with turbo superchargers possessed level flight performance of
400mph or more.
1930s | High-Performance Piston Enginges
America’s early experiments
with closed cockpits included
the Curtiss XP- 31, shown here
with a radial, rather than an
in-line, engine. (Photo courtesy of Wikimedia Commons)
(Clockwise from top left) The
Allison V-1750 powered the
P- 40 and P- 38. The legendary
Rolls-Royce Merlin powered
Spitfires and Hurricanes, and the
Packard-built version turned the
Mustang into a legend of its own.
Daimler-Benz’s fuel-injected DB
series (in this case, a DB 605 in
a Bf 109G) could be pushed into
negative G without faltering;
Merlins couldn’t do the same.
The Pratt & Whitney R-2800
was in the nose of almost
every round-nose, mainstream
American fighter. (Photos by