If you’ve never seen a Corsair before, your first
glance at the outsized propeller and "bent" wings might leave you with the
feeling that either this warbird was assembled from parts that didn’t
match or it has met with some sort of disaster. But from all these
outsized and mismatched parts came one of WWII’s greatest fighter planes.
It could outfight, outclimb and (if need be) outrun any prop driven enemy.
The US Navy Bureau of Aeronautics had a long tradition of issuing
proposals for aircraft which pushed the limits of available technology.
This stimulated the manufacturers ability to respond with new technology
to meet the challenge. When "BuAer" sent its proposal for a high
performance, carrier based fighter to United Aircraft Corporation (parent
company of Vought-Sikorsky) on February 1, 1938, it seemed the Navy might
have pushed technology to the point of giving it a hernia. C. J. McCarthy,
who was Vought’s General Manager, called in the company’s chief engineer,
Rex Beisel. Rex was one of those people who lived by the old motto "The
difficult we do immediately. The impossible will take a week, ten days at
the most." An elite team was selected for the development of Vought Design
#V-166; Frank Albright as project engineer; Paul Baker as aerodynamics
engineer; James Shoemaker as propulsion engineer. Each had an assistant.
These engineers submitted their work to Beisel who then integrated it all
into a final design.
Early on, Shoemaker chose the Pratt-Whitney R-1830 Wasp air-cooled radial
engine because of it’s long history of reliability, and the V-166-A was
designed around this engine. But, in 1940, the BuAer’s quest for speed
resulted in a switch to the experimental XR-2800-4 version of the
Pratt-Whitney Double Wasp, with a two-stage supercharger for the prototype
XF4U-1 Corsair. The R-2800 engine was the most powerful engine in the
world in 1940, exceeding 100 hp (74.6 kW) per cylinder for each of its 18
cylinders. The change in engines resulted in the design number being
changed to Vought Design #V-166-B. The V-166-A was never built.
With the awesome 2,804 cubic inch (46 liter) Double Wasp
air-cooled radial engine developing 1,850 hp (1,380.6 kW), the only way to
convert that kind of horsepower efficiently into thrust was with a huge
Hamilton Standard Hydromatic, 3 blade prop which measured 13 feet 4 inches
(4.06 meters) in diameter. And that created a problem of deck clearance
for the prop. It seemed either the main landing gear had to be lengthened,
or the prop had to be shortened.
Since the landing gear had to be very strong to withstand the pounding of
a carrier deck landing, a short, stout leg was required. Also, there
wouldn’t be enough room in the wing to properly stow a longer gear. And,
if the prop were shortened, much of the horsepower of the Double Wasp
would be wasted. So, Vought engineers came up with the distinctive
inverted gull-wing design which forever characterized the F4U Corsair.
This "bent wing" design allowed the huge prop to clear the deck while
providing for a short, stout landing gear. And, as a byproduct, the wing
also improved the aerodynamics of the intersection where the wing attaches
to the fuselage, boosting the top speed.
It was a very "slick" looking plane using flush riveting and a new
technique developed jointly by Vought and the Naval Aircraft Factory
called "spot-welding". In order to make the Corsair as aerodynamically
clean as possible, there was nothing protruding into the air stream. The
intake for the turbo-supercharger, intercooler and the oil cooler were
located in slots in the inboard leading edges of the wings. Vought
designed the fuselage with a circular cross-section which fit snugly over
the Pratt-Whitney engine. The F4U was the first Navy craft to have landing
gear which retracted flush into the bottom of the wing, though it took
some effort. Other craft had retracting gear, but there was always some
bulge or part of the wheel exposed. Vought engineers designed the Corsairs
wheels to swivel 90º and retract straight back to fit flat inside the
bottom of the wing. Two panels then closed over the gear making a
perfectly smooth fairing. The idea was to mate the most powerful engine
with the smallest, cleanest possible airframe.
F4U's (Corsairs) returning from a combat mission
over North Korea circle the
USS Boxer as they wait for planes in the next strike to be launched from
her flight deck.
A helicopter hovers above the ship.
The XF4U-1 first went aloft on May 1, 1940 and five
months later flew the 45 miles (73 km) between Stratford and Hartford,
Connecticut at a speed of 405 miles per hour (651.8 kph), becoming the
first production aircraft to exceed 400 mph in level flight. The US Navy
was very pleased with the performance of the Corsair and, in June 1941,
ordered 584 copies. Over the next 11 years that figure would grow to over
Several stumbling blocks developed when carrier trials were held aboard
the USS Sangamon and other carriers in late 1941. The biggest problem was
the long nose. It stuck out 14 feet (4.27 m) in front of the pilot, and
when the Corsair was sitting in take-off position, the nose pointed up at
an angle sufficient to block forward vision to about 12º above the horizon.
In carrier landings it was practically impossible to see the Landing
Signals Officer once the Corsair was lined up with the carrier deck on
final approach. Adding to this problem were oil and hydraulic leaks from
the engine compartment which seeped past the cowl flaps and smeared the
windshield, further restricting visibility.
The Corsair's distinctive sound, which earned it among the
Japanese the nick-name of
"Whistling Death", partly because of the engine sound, that was caused by
inlets for engine air. Shown above is Maj. Gregory Boyington's F4U from VMF-214.
Vought F4U Corsair
Landing on a carrier deck required the pilot to have the plane at stall
speed just as the tail-hook snagged the deck wire, but this was made very
difficult by the wicked stall characteristics of the F4U. Just as stall
speed was reached, the left wing tended to drop like a rock. In a deck
landing this could cause the landing gear to collapse resulting in
injuries to the pilot and severe damage to the aircraft. Assuming luck was
with the pilot and he landed intact, the Corsair normally "bottomed out"
the shock absorbers as it slammed down on the deck. The resulting recoil
caused the plane to bounce high in the air. The tailhook itself sometimes
failed to "trap" the plane by engaging an arrestor wire. If this happened
on a straight deck carrier it usually meant the aircraft plowed into the
planes parked forward. It was said on a straight deck carrier there were
only two kinds of landings; a "trap" and a catastrophe!
As the Corsair was thought by the Navy to be unsuitable for carrier duty,
it was given to the U.S. Marines for land-based operations where it earned
an outstanding combat record. Britain, France, New Zealand, Australia also
received the F4U during WWII.
F4U Corsair from US Marines VMF-511, USS Block
It was the British who finally worked out a method of
landing the Corsair on their carriers in spite of the visibility problems
caused by the long nose. Instead of the normal downwind-crosswind-final
approach method, the British simply turned downwind, then made a slow,
continuous curve which aligned the Corsair with the deck only at the last
second before the aircraft touched down and trapped. This method allowed
the pilot to keep the Landing Signals Officer in view right up to the
moment the plane was over the fan-tail where the LSO gave the sign to
either "cut" or make another attempt.
To alleviate the problem of oil and hydraulic fluid smearing the
windshield, the Brits simply wired shut the cowl flaps across the top of
the engine compartment, diverting the oil and hydraulic fluid around the
sides of the fuselage. Numerous other simple, effective alterations were
devised to alleviate the dreadful stall characteristics, landing bounce
and tailhook problems (among others), and these modifications were
incorporated into the production line. In 1944 the US Navy decided to
again try landing the F4U on carriers, and this time succeeded. It turned
out to be an extremely wise decision.
As the nature of the war changed, the Corsair also changed. There were
seven different dash numbers, some built exclusively for foreign countries
(the F4U-7 for the French Aeronavale), and one was never built at all (the
F4U-6). Some dash numbers had letter suffixes designating different
changes in the airframe, weapons or engine. In addition to Vought, the
Corsair was built by the Goodyear Aircraft Company, with a lesser
production run by Brewster Aeronautical Corporation.
There were also night fighter versions (designated by
the suffix letter "N"), and photo versions (with the suffix "P"). The
Corsair underwent over 950 major engineering changes over is lifetime
though none changed the distinctive profile of the F4U. Most often,
production aircraft were simply pulled off the assembly line and used as
test beds. Some of these were designated prototypes with the prefix "X"
(such as the "XF4U-3"). By the end of Corsair production 1952, there
were 16 separate models on the books.
Depending on which Air Squadron you were in, the F4U had many nicknames:
"Hose Nose", "Bent Wing Bird", "Hog" and "Ensign Eliminator", the latter
due to it’s stall and landing characteristics. Under the right
circumstances, the wing mounted air intakes caused a pronounced
whistling sound. For that reason, Japanese ground troops called it "Whistling
Several varieties of the Pratt-Whitney R-2800 Double Wasp radial engine
were used in the Corsair. Some used a water-methanol injection to
increase the power for short sprints. This was called "War Emergency"
power and had a suffix "W" after the dash number of the engine. During
the Korean War, there were modifications to cope with the extreme cold
encountered in that theater. These were designated with the suffix "L" (for
The XF4U-1 was of course the
original prototype with a greenhouse type canopy and the Pratt-Whitney
R-2800-4 radial which delivered 1,850 hp (1,380.6 kW) for take-off and
1,460 hp (1,089.6 kW) at 21,500 feet (6,553.2 meters). It had two .50 cal.
(12.7 mm) Colt-Browning machine guns mounted in the nose and each wing
held two more for a total of six. Its top speed was 405 mph (651.77 kph).
It weighed in at a maximum 10,074 pounds (4,569.4 kilograms) and had a
range of 1,070 miles (1,722 km).
The F4U-1 was the first production type. It started rolling off the
assembly lines in September 1942. The production "dash one" had some
changes made to the canopy for better vision to the rear, though this
would continue to be a problem until the advent of the "bulged" canopy
introduced in the F4U-1A.
The two Colt-Browning .50s mounted in the nose of the prototype were
removed and all six machine guns were mounted in the wings outside the
propeller arc which eliminated the need for synchronization. The dash one
also featured the Pratt-Whitney R-2800-8 engine. Some were produced with
"-8W" engines. Both engines produced 2,000 hp (1,492.5 kW) for take-off,
with the water injected -8W producing an extra 250 hp (186.6 kW) for war
emergency. Suffix letters for the dash one Corsair ran from "A" to "D" and
the "P" photo model.
F4U-2 was a night fighter version of the dash one. For
reasons known only to the US Navy, instead of calling it the "F4U-1N" (a
method it used on all succeeding models), they gave it the dash two
designation. The dash one was transformed into the dash two by modifying
the starboard wing and the radio bay in the fuselage to accept the "XAIA"
("Experimental Airborne Intercept [model] A") radar which was hand-built.
The starboard wing was modified by removing the outboard .50 cal. (12.7
mm) Colt-Browning and altering the wing to support the radar scanner. The
radio was removed and placed beneath the pilot’s seat and the radar set
was placed in the radio bay. There were other slight modifications such as
bore sighting the guns to converge fire at 250 yards (228.6 m) and were
angled slightly upward so the pilot could fire without bouncing around in
the target’s slip-stream. There were no tracers loaded so as not to blind
the pilot when firing. The engine was fitted with exhaust flame dampers.
After radar installation, the aircraft weighed 235 pounds less than the
standard dash one.
The F4U-3 was a bump in the evolution of the Corsair. The US Navy had for
many months kicked around the idea of a high altitude (40,000+ ft)
(12,192+ m) version of the F4U. Toward the latter half of 1943, they
approached Vought with the scheme and Vought designer Russell Clark went
to work molding the Corsair fuselage around the XR-2800-16 Double Wasp
engine which was fitted with two Bierman model 1009A turbo-superchargers.
At first the project looked very promising with the engine producing 2000
hp (1,492.5 kW) at 40,000 ft (12,192 m). But defects in the
turbo-superchargers caused the project to be dropped after a few copies
had been produced and tested. The dash three could be identified by a
large intake tube fitted to the belly below the engine.
The F4U-4 was one of the more important variants of the
Corsair. Seven prototypes were built, anticipating the many problems which
would arise from the proposed changes. Five F4U-1s were pulled from the
production line to be modified into the XF4U-4A, ‘4B, ‘4C, ‘4D and’4E. Two
more "FG-1" aircraft (identical to the Vought F4U-1) were pulled from
Goodyear’s production line. They were all fitted with the Pratt-Whitney
R-2800-18W engine which produced 2,100 hp (1,567 kW) and sported a new
four blade prop. The engine also had methanol-water injection which
boosted the war emergency power rating to 2,450 hp (1,828 kW) for about
five minutes. The 18W engine necessitated changes in the basic airframe to
handle the extra power and the turbo air intake was mounted on the inside
bottom of the engine cowling (it was called a "chin scoop") while air for
the intercooler and oil cooler continued to be drawn from the wing slots.
The F4U-4 was clocked at a top speed of 446 mph (717.75 kph) at 26,200 ft
Although it wasn’t designated by the Navy as such, the dash four was a
fighter-bomber for all intents and purposes. It had 6 Colt-Browning .50
cal. (12.7 mm) wing mounted machine guns (the F4U-4C substituted four 20
mm cannon), plus it could carry two 1,000 lb (453.6 kg) bombs or eight 5
inch (127 mm) rockets. The first 300 of the production F4U-4Cs were
assigned to Marine Air Group 31 and were taken into the Battle for Okinawa
aboard the escort carriers Sitko Bay and Bereton. The Army and Marine
riflemen who fought that battle on the ground remember the F4U-4 as the "Sweetheart
of Okinawa" and it undoubtedly saved many hundreds of their lives.
The prototype "Dash Five" was flown in December 1945, a few months after
World War Two had ended. It utilized all the knowledge built up over the
war years and major changes were made to upgrade the F4U-5 Corsair. First,
the engine was changed to the Pratt-Whitney R-2800-32W. This was called a
"Series E" engine and featured a dual supercharger to boost engine power
to 2,350 hp (1,753.7 kW) at 26,200 ft (7,985.8 m). War emergency power was
boosted to 2,760 hp (2,059.7 kW). The dual supercharger necessitated
removing the chin scoop and installing two "cheek" scoops inside the
Due to the higher horsepower, the fuselage was lengthened by 5 inches (127
mm) and the engine angled down about 2º to provide more stability. Until
the dash 5, the outer top wing panels and the control surfaces of the
Corsair had been fabric covered. At speed, the fabric tended to deform and
slow the aircraft by a few miles per hour. The F4U-5 had all fabric
surfaces replaced with sheet duralumin to minimize this problem. Armament
was the same as the F4U-4.
Shown above is the F4U Corsair of Lt. J.G. Ira
Kepford from US Navy VF-17, circa 1944.
A few improvements were made solely for pilot comfort.
Cockpit heating was redesigned, controls were made easier to operate and/or
automatic. Armrests were installed on the seat, which reclined slightly.
With the improvements and the -32W engine, the dash five could operate
very comfortably at altitudes approaching 45,000 feet (13,716 meters).
The AU-1 project began life as the F4U-6 but was quickly redesignated by
the Navy to reflect its ground attack role. The dash six was never built.
The AU-1 was produced solely for the US Marines during the height of the
Korean War. Deliveries began in January 1952 and a total of 111 were
supplied during the year. The AU-1 was powered by an R-2800-83W Double
Wasp with a single stage supercharger, developing 2,300 hp (1,716.4 kW)
for take off and 2,800 hp (2,089.6 kW) for War Emergency. Extra armor was
added for protection from the small arms fire which would be encountered
at the lower altitudes where the AU-1 would be working. It’s ground attack
role was underlined by the statistics; max take-off weight was almost 10
tons (9071.9 kg) while the service ceiling was only 19,500 ft (5,943.6 m)
and the maximum speed was a mere 238 mph (383 kph)! Ground attack required
only enough speed to present a difficult target for ground fire and only
enough altitude to properly aim it‘s weapons.
The AU-1 was armed with 10 rockets or 4,000 lbs (1,814.4 kg) of bombs, in
addition to four wing mounted 20 mm cannon with 230 rounds per gun. A
fully armed AU was an awesome war machine!
The F3A-1 was produced by the Brewster Aeronautical Corporation and was
identical to the F4U-1. Internal management problems at the corporation
caused the Navy to end Brewster production in 1944 after over a year in
which only 735 aircraft rolled off the Brewster assembly line.
Goodyear produced a number of Corsair models identical to the Vought
models. But since it was easier to interrupt Goodyear production than
Vought, some experimental models were also constructed. Most notably the
F2G series which featured an entirely new engine; the Pratt-Whitney
R-4360-4 "Wasp Major". The airframe received significant alterations in
order to mount this engine. The Wasp Major could deliver 3,000 hp (2,238.8
kW) for take-off and 2,400 hp (1,791 kW) at 13,500 feet (4,114.8 m). Top
speed was 431 at 16,400 ft (4,998.7 m). It was armed with four .50 cal.
(12.7 mm) Browning machine guns with 300 rounds per gun, and could carry
two 1,600 lb (725.8 kg) bombs on wing pylons. The F2G-1 was the land based
version, while the F2G-2 was the carrier model. Although hundreds were on
order by August 1945, only 5 examples of each were built due to
cancellations at the end of hostilities. All ten of these were sold as
surplus, and a few could be found at various air races around the country
after the war.
The entire production run of the F4U-7 was tailored specifically for the
French Navy (the "Aeronavale"). Ninety-four copies were built and all were
sold to the Aeronavale. The dash seven was an upgrade of the AU-1 built
specially for ground attack. Production of the dash seven began in June,
1952 and when the last one was delivered to the French in December of that
year, the long production run of the Vought F4U Corsair came to an end.