Republic P-47 Thunderbolt

https://en.wikipedia.org/wiki/Republic_P-47_Thunderbolt

also see
https://nationalinterest.org/blog/bu...r-plane-133802

The Republic P-47 Thunderbolt was a World War II-era fighter aircraft produced
by the United States from 1941 through 1945. Its primary armament was eight
..50-caliber machine guns, and in the fighter-bomber ground-attack role it could
carry five-inch rockets or a bomb load of 2,500 pounds (1,103 kg). When fully
loaded, the P-47 weighed up to eight tons, making it one of the heaviest
fighters of the war. The P-47 was designed around the powerful Pratt & Whitney
R-2800 Double Wasp engine, which was also used by two U.S. Navy/U.S. Marine
Corps fighters, the Grumman F6F Hellcat and the Vought F4U Corsair. The
Thunderbolt was effective as a short-to medium-range escort fighter in
high-altitude air-to-air combat and ground attack in both the European and
Pacific theaters.

The P-47 was one of the main United States Army Air Forces (USAAF) fighters of
World War II, and also served with other Allied air forces, including those of
France, the United Kingdom, and the Soviet Union. Mexican and Brazilian
squadrons fighting alongside the USAAF also flew the P-47.

The armored cockpit was relatively roomy and comfortable and the bubble canopy
introduced on the P-47D offered good visibility. A present-day U.S.
ground-attack aircraft, the Fairchild Republic A-10 Thunderbolt II, takes its
name from the P-47.

The P-47 Thunderbolt was designed by Alexander Kartveli, a Russian immigrant of
Georgian ethnicity. It was to replace the Seversky P-35 developed earlier by
Russian immigrant Alexander P. de Seversky. Both had fled from their homeland to
escape the Bolsheviks. In 1939, Republic Aviation designed the AP-4 demonstrator
powered by a Pratt & Whitney R-1830 radial engine with a belly-mounted
turbocharger. A small number of Republic P-43 Lancers were built but Republic
had been working on an improved P-44 Rocket with a more powerful engine, as well
as on the AP-10 fighter design. The latter was a lightweight aircraft powered by
the Allison V-1710 liquid-cooled V-12 engine and armed with eight .50 in (12.7
mm) M2 Browning machine guns. The United States Army Air Corps (USAAC) backed
the project and gave it the designation XP-47.

Power came from a Pratt & Whitney R-2800 Double Wasp two-row 18-cylinder radial
engine producing 2,000 hp (1,500 kW)—the same engine that would power the
prototype Vought XF4U-1 fighter to just over 400 mph (644 km/h) in October
1940—with the Double Wasp on the XP-47B turning a four-bladed Curtiss Electric
constant-speed propeller of 146 in (3.7 m) in diameter. The loss of the AP-4
prototype to an engine fire ended Kartveli's experiments with tight-fitting
cowlings, so the engine was placed in a broad cowling that opened at the front
in a "horse collar"-shaped ellipse. The cowling admitted cooling air for the
engine, left and right oil coolers, and the turbosupercharger intercooler
system. The engine exhaust gases were routed into a pair of wastegate-equipped
pipes that ran along each side of the cockpit to drive the turbosupercharger
turbine at the bottom of the fuselage, about halfway between cockpit and tail.
At full power, the pipes glowed red at their forward ends and the turbine spun
at 21,300 rpm. The complicated turbosupercharger system with its ductwork gave
the XP-47B a deep fuselage, and the wings had to be mounted in a relatively high
position. This was difficult since long-legged main landing gear struts were
needed to provide ground clearance for the enormous propeller. To reduce the
size and weight of the undercarriage struts and so that wing-mounted machine
guns could be fitted, each strut was fitted with a mechanism by which it
telescoped out 9 in (23 cm) when extended.

The XP-47B was very heavy compared with contemporary single-engined fighters,
with an empty weight of 9,900 lb (4,490 kg), or 65 per cent more than the YP-43.
Kartveli said, "It will be a dinosaur, but it will be a dinosaur with good
proportions". The armament was eight .50 caliber (12.7 mm) "light-barrel"
Browning AN/M2 machine guns, four in each wing. The guns were staggered to allow
feeding from side-by-side ammunition boxes, each with 350 rounds. All eight guns
gave the fighter a combined rate of fire of approximately 100 rounds per second.

The XP-47B first flew on 6 May 1941 with Lowry P. Brabham at the controls.
Although there were minor problems, such as some cockpit smoke that turned out
to be due to an oil drip, the aircraft proved impressive in its early trials. It
was lost in an accident on 8 August 1942 but before that mishap, the prototype
had achieved a level speed of 412 mph (663 km/h) at 25,800 ft (7,864 m) altitude
and had demonstrated a climb from sea level to 15,000 ft (4,600 m) in five
minutes.

P-47N

The P-47N was the last Thunderbolt variant to be produced. It was designed as an
escort fighter for the Boeing B-29 Superfortress bombers flying raids on the
Japanese home islands. Increased internal fuel capacity and drop tanks had done
much to extend the Thunderbolt's range during its evolution, and the only other
way to expand the fuel capacity was to put fuel tanks into the wings. Thus, a
new wing was designed with two 50 U.S. gallon (190 l) fuel tanks. The third
YP-47M prototype (42-27387) was fitted with this wing and became the YP-47N; its
designation was later changed to XP-47N. This redesigned aircraft first flew in
July 1944. The redesign proved successful in extending the range to about 2,000
mi (3,200 km), and the squared-off wingtips improved the roll rate. The P-47N
entered mass production with the R-2800-57 engine, and later used the upgraded
R-2800-73 or -77. A total of 1,816 were built. The very last Thunderbolt to be
built, a P-47N-25, rolled off the production line in October 1945.

At the end of production, a Thunderbolt cost $83,000 in 1945 U.S. dollars. A
total of 15,636 Thunderbolts of all types were built.


Role
Fighter-bomber

Manufacturer
Republic Aviation

Designer
Alexander Kartveli

First flight
6 May 1941

Introduction
November 1942

Retired
1966, Peruvian Air Force

Primary users
United States Army Air Forces
Royal Air Force
French Air Force

Produced
1941–1945

Number built
15,636

Unit cost

US$83,000 in 1945

Variants
Republic XP-72

US service

By the end of 1942, P-47Cs were sent to England for combat operations. The
initial Thunderbolt flyers, 56th Fighter Group, was sent overseas to join the
8th Air Force. As the P-47 Thunderbolt worked up to operational status, it
gained a nickname: the "Jug" (because its profile was similar to that of a
common milk jug of the time). Two Fighter Groups already stationed in England
began introducing the Jugs in January 1943: the Spitfire-flying 4th Fighter
Group, a unit built around a core of experienced American pilots who had flown
in the RAF Eagle Squadrons prior to the US entry in the war; and the 78th
Fighter Group, formerly flying P-38 Lightnings.

Beginning in January 1943, Thunderbolt fighters were sent to the joint Army Air
Forces – civilian Millville Airport in Millville, New Jersey in order to train
civilian and military pilots.

The first P-47 combat mission took place 10 March 1943 when the 4th FG took
their aircraft on a fighter sweep over France. The mission was a failure due to
radio malfunctions. All P-47s were refitted with British radios, and missions
resumed 8 April. The first P-47 air combat took place 15 April with Major Don
Blakeslee of the 4th FG scoring the Thunderbolt's first air victory (against a
Focke-Wulf Fw 190).

By mid-1943, the Jug was also in service with the 12th Air Force in Italy and
against the Japanese in the Pacific, with the 348th Fighter Group flying
missions out of Port Moresby, New Guinea. By 1944, the Thunderbolt was in combat
with the USAAF in all its operational theaters except Alaska.

Luftwaffe ace Heinz Bär said that the P-47 "could absorb an astounding amount of
lead [from shooting at it] and had to be handled very carefully". Although the
North American P-51 Mustang replaced the P-47 in the long-range escort role in
Europe, the Thunderbolt still ended the war with 3,752 air-to-air kills claimed
in over 746,000 sorties of all types, at the cost of 3,499 P-47s to all causes
in combat. By the end of the war, the 56th FG was the only 8th Air Force unit
still flying the P-47, by preference, instead of the P-51. The unit claimed
677.5 air victories and 311 ground kills, at the cost of 128 aircraft.
Lieutenant Colonel Francis S. Gabreski scored 28 victories, Captain Robert S.
Johnson scored 27 (with one unconfirmed probable kill leading to some giving his
tally as 28), and 56th FG Commanding Officer Colonel Hubert Zemke scored 17.75
kills. Despite being the sole remaining P-47 group in the 8th Air Force, the
56th FG remained its top-scoring group in aerial victories throughout the war.

Aerial warfare

Initial response to the P-47 praised its dive speed and high-altitude
performance while criticizing its turning performance and rate of climb
(particularly at low-to-medium altitudes). The turbosupercharger in the P-47
gave the powerplant its maximum power at 27,000 ft (8,230 m), and in the thin
air above 30,000 ft (9,144 m), the Thunderbolt remained comparatively fast and
nimble relative to other aircraft.

The P-47 first saw action with the 4th Fighter Group. The Group's pilots were
mainly drawn from the three British Eagle Squadrons who had previously flown the
British Supermarine Spitfire Mark V, a much smaller and much more slender
aircraft. At first, they viewed their new fighter with misgivings. It was huge;
the British pilots joked that a Thunderbolt pilot could defend himself from a
Luftwaffe fighter by running around and hiding in the fuselage. Optimized for
high altitude work, the Thunderbolt had 5 feet (1.5 m) more wingspan, a quarter
more wing area, about four times the fuselage volume, and nearly twice the
weight of a Spitfire V. One Thunderbolt pilot compared it to flying a bathtub
around the sky. When his unit (4th Fighter Group) was equipped with
Thunderbolts, ace Don Blakeslee said, referring to the P-47's vaunted ability to
dive on its prey, "It ought to be able to dive. It certainly can't climb."
(Blakeslee's early-model P-47C had not been fitted with the new paddle blade
propeller). The 4th Fighter Group's commander hated the P-47, and his prejudices
filtered down to the group's pilots; the 4th had the fewest kills of any of the
first three P-47 squadrons in Europe.

The U.S. ace Jim Goodson, who had flown Spitfires with the RAF and flew a P-47
in 1943, at first shared the skepticism of other pilots for their "seven-ton
milk-bottles". But Goodson learned to appreciate the P-47's potential: "There
were many U.S. pilots who preferred the P-47 to anything else: they do not agree
that the (Fw) 190 held an overall edge against it."

Some P-47 pilots claimed to have broken the sound barrier, but later research
revealed that because of the pressure buildup inside the pitot tube at high
speeds, airspeed readings became unpredictably exaggerated. But German pilots
gradually learned to avoid diving away from a Thunderbolt. Kurt Bühligen, a
high-scoring German fighter ace with 112 victories, recalled:

"The P-47 was very heavy, too heavy for some maneuvers. We would see it coming
from behind, and pull up fast and the P-47 couldn't follow and we came around
and got on its tail in this way.

Ground attack role

The P-47 proved to be a formidable fighter-bomber due to its good armament,
heavy bomb load and ability to survive enemy fire. The P-47's survivability was
due in part to its radial piston engine, which unlike comparable liquid-cooled
engines, had a high tolerance for damage. The Thunderbolt's eight .50 in (12.7
mm) machine guns were capable against lightly armored targets, although less so
than cannon-armed aircraft of the day. In a ground attack role, the
armor-piercing (AP), armor-piercing incendiary (API), and armor-piercing
incendiary tracer (APIT) ammunition proved useful in penetrating thin-skinned
and lightly armored German vehicles and exploding their fuel tanks, as well as
occasionally damaging some types of enemy armored fighting vehicles (AFVs).

Specifications (P-47D-30 Thunderbolt)

General characteristics
Crew: 1
Length: 36 ft 1 in (11.00 m)
Wingspan: 40 ft 9 in (12.42 m)
Height: 14 ft 8 in (4.47 m)
Wing area: 300 sq ft (28 m2)
Airfoil: Seversky S-3
Empty weight: 10,000 lb (4,536 kg)
Gross weight: 12,731 lb (5,775 kg)
Max takeoff weight: 17,500 lb (7,938 kg)
Powerplant: 1 × Pratt & Whitney R-2800-59B 18-cylinder air-cooled radial piston
engine, 2,600 hp (1,900 kW)
Propellers: 4-bladed constant-speed propeller

Performance
Maximum speed: 433 mph (697 km/h, 376 kn) at 29,000 ft (8,839 m)
Combat range: 800 mi (1,300 km, 700 nmi)
Ferry range: 1,800 mi (2,900 km, 1,600 nmi)
Service ceiling: 43,000 ft (13,000 m)
Rate of climb: 3,180 ft/min (16.2 m/s)
Wing loading: 42.43 lb/sq ft (207.2 kg/m2)
Power/mass: 0.204 hp/lb (0.335 kW/kg)

Armament

8 × .50 in (12.7 mm) M2 Browning machine guns (3400 rounds)
Up to 2,500 lb (1,134 kg) of bombs
10 × 5 in (127 mm) unguided rockets