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THE 456th FIGHTER INTERCEPTOR SQUADRON |
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T PROTECTORS OF S. A. C. |
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The Boeing B-29 "Superfortress" |
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The B-29
The Boeing B-29 was designed in 1940 as an eventual replacement for the B-17 and B-24. The first one built made its maiden flight on September 21, 1942. In December 1943 it was decided not to use the B-29 in the European Theater, thereby permitting the airplane to be sent to the Pacific area where its great range made it particularly suited for the long over-water flight required to attack the Japanese homeland from bases in China. During the last two months of 1944, B-29s began operating against Japan from the islands of Saipan, Guam and Tinian.
With the advent of the conflict in Korea in June 1950, the B-29 was once again thrust into battle. For the next several years it was effectively used for attacking targets in North Korea.
The B-29 on display, named "Bockscar," was flown to the U.S. Air Force Museum on September 26, 1961. It is the airplane from which the second atomic bomb was dropped on Nagasaki on August 9, 1945.
SPECIFICATIONS
Span: 141 ft. 3 in.
Length: 99 ft. 0 in.
Height: 27 ft. 9 in.
Weight: 133,500 lbs. max.
Armament: Eight or ten .50-cal. machine guns in remote controlled turrets plus two .50-cal. machine guns and one 20mm cannon in tail; 20,000 lbs. of bombs
Engines: Four Wright R-3350s of 2,200 hp. ea.
Cost: $639,000
Serial Number: 44-27297PERFORMANCE
Maximum speed: 357 mph.
Cruising speed: 220 mph.
Range: 3,700 miles
Service Ceiling: 33,600 ft.
The Wright R-3350-57 "Cyclone" Engine
Aircraft engine design made great advances during the war years. Piston engines reached a level of power and performance that was startling and a new type of power plant, the turbojet came into being. Tremendous effort went toward creating an aircraft engine that could deliver one horsepower for each pound of weight. This was achieved most notably in the Wright Cyclone R-3350 engine, four of which powered the giant B-29 bomber.
There are two main types of piston engines; radial or air-cooled and inline or liquid-cooled. Radial engines typically have a large area to facilitate cooling but this also increases drag - not an attribute you want when designing a fighter plane. This is why inline or liquid cooled engines were used in the majority of front-line fighters during the war including the P-51 Mustang, the Spitfire, and the Messerschmitt Bf 109. It took clever design and engineering to produce a high-performance radial engine fighter aircraft. This was accomplished with the Focke-wulf Fw-190D and P-47 Thunderbolt fighters.
An additional issue is the greater vulnerability of liquid-cooled engines to gunfire and damage since even a single bullet hole in the coolant lines could led to engine loss within minutes. While this is a valid criticism most aircraft designer's went with inline engines for fighters and its hard to argue with the results.
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The Wright R-3350 "Cyclone"
The Wright R-3350 "Cyclone" was one of the most powerful radial aircraft engines produced in the United States. The first R-3350 was run in May 1937, and later versions of this engine remained in production into the 1950s. Thousands were built to power both military and commercial aircraft during this time. Its first major military use was in the Boeing B-29 during World War II. Subsequent versions were used in the C-119, C-121, A-1 Skyraider, and several Navy and commercial aircraft.
The R-3350 is a twin row, supercharged, air-cooled, radial engine with 18 cylinders and a displacement of 3,350 cubic inches. Horsepower ranges from 2,200 to over 2,800, depending on the model.
Courtesy Of The Air Force Museum
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The Wright R-3350 "Cyclone"
Wright Aeronautical Corporation. R-3350 Duplex Cyclone engine - twin row, supercharged, air-cooled, radial engine with 18 cylinders and a displacement of 3,350 cubic inches. Two General Electric B-11 superchargers, one on each side of the nacelle.
2,200 hp R-3350-13 17ft 0" (5.18m) three-blade propellers 3 XB-29s
2,200 hp R-3350-21 17ft 0" (5.18m) three-blade propellers 14 service-test YB-29s
2,200 hp R-3350-23 16ft 7" (5.05m) four-blade Hamilton Standard constant-speed, full feathering propellers B-29s
R-3350-41; R-3350-57; R-3350-57AR-3350-57 Specs
Type: Air-cooled, 18-cylinder twin-row radial engine
Country/Date: U.S.A., 1942
Rating: 2,200 hp @ 2800 rpm
Displacement: 3,350 cu. in.
Weight: 2,779 lbs.
Bore & Stroke: 6.125" & 6.3"The immensely powerful Wright R-3350 was chosen as the power plant for the B-29. Four of these massive engines provided the power to move each B-29. Problems with overheating were legendary but were overcome with numerous field modifications and changes in engine use. Altogether the R-3350 went through tens of thousands of design changes during its early development. Pilots learned to use as much of the runway as possible and build up speed to help cool the engines before slowing climbing for altitude.
Work on the engine began in January 1936 and the first one ran in May 1937. It was similar in design to the company's R-2600 14-cylinder radial, sharing the same bore and stroke but adding two more cylinders per row for additional displacement. A three-piece forged aluminum (later changed to steel) crankcase, cast heads and a magnesium supercharger case to reduce weight. Downdraft carburetion on early engines yielded mixture inconsistencies between the front and rear cylinder rows, which was solved on later models by changing to a direct fuel injection system.
Wright Aeronautical built a new facility at Woodbridge, NJ for the R-3350 and shifted production at their Cincinnati plant exclusively to the Wright engine. Total output between these two plants approached 13,800. Chrysler's Dodge Chicago Division, supplied over 18,400 engines from their Chicago, IL location. As design problems were overcome the R-3350 saw its time between overhauls increase from 100 to 400 hours by the end of the war.
Almost all of the engine nacelles, as big as a fighter fuselage, were made by the Fisher Body division of General Motors. Cleveland facility.
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The Wright R-3350 "Cyclone"
In this view you can see two of the three Power Recovery Turbines that are attached to this Turbo Compound R-3350. They are the round silver and black objects mounted about halfway back on the engine. They added about 600 additional horsepower to the basic engine. They were plumbed into the exhaust of the Cyclone engine which spun up the turbines. These turbines then turned a shaft which was splined directly back into the output shaft of the engine. This was a very efficient way to turn about 20% of the engines heat energy that was normally wasted into usable power for the engine.
The Remote-Controlled Gunnery System
Four companies competed for the contract including Bendix, General Electric, Sperry, and Westinghouse. General Electric developed the system used in the B-29 consisting of four turrets and a tail mount.
M5 Director General Electric fire control system
The bomber is provided with a system of electrically powered gun turrets which are operated by a sighting system in order to concentrate a broadside fire on enemy planes approaching from any angle. One of the vital elements of this sighting system is the mechanical-electrical computer whose function it is to make instant corrections for the speed of the bomber, the speed and direction of the attacking plane, altitude, temperature, wind age, gravity, and the ballistics of the gun projectile. In addition, it makes correction for parallax - the distance between the sighting station and the remotely located guns.Production of M5 Director by the Singer Company Elizabethport Works
Starting in September 1943, weekly production stepped up gradually, reaching a rate of approximately 250 complete Computers per week at the end of 1944, and over 500 per week in July 1945, at which time a total of 20,794 complete Computers had been shipped out of the factory. About one-third of these Computers have been Double Computers, incorporating two computer mechanisms. In the Spring of 1945 the Double Computer was discontinued but the cancellation of this quantity was partly compensated for by some increase in the requirements of the Single Computer.
The Pressurized Cabin