Tag Archives: Heavy Bomber

30 May 1942

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A Boeing B-17F Flying Fortress takes off from Boeing Field, Seattle, Washington, 1942.
A Boeing B-17F Flying Fortress takes off from Boeing Field, Seattle, Washington, 1942.

30 May 1942: The Boeing B-17F Flying Fortress makes its first flight. B-17F-1-BO 41-24340 was the first of a new series of the famous World War II bomber. While visually similar to the B-17E, it had more than 400 improvements based on early wartime experience with the B-17D and B-17E.

The Boeing B-17F Flying Fortress was a four-engine heavy bomber operated by a flight crew of ten. It was 74 feet, 8.90 inches (22.781 meters) long with a wingspan of 103 feet, 9.375 inches (31.633 meters) and an overall height of 19 feet, 1.00 inch (5.187 meters). The wings have 3½° angle of incidence and 4½° dihedral. The leading edge is swept aft 8¾°. The total wing area is 1,426 square feet (132.48 square meters). The horizontal stabilizer has a span of 43 feet (13.106 meters) with 0° incidence and dihedral. Its total area, including elevators, is 331.1 square feet (12.18 square meters).

Boeing B-17F Flying Fortress
Boeing B-17F-95-BO Flying Fortress 42-30243, near Mount Rainier, Washington, circa May 1943. Note the underwing bomb racks. It was assigned to the 331st Bombardment Squadron), 94th Bombardment Group (Heavy), marked QE Z, and named “Nip ‘n’ Tuck.” This bomber crashed at Évreaux, Normandy, France, 14 July 1943. 8 crew members were captured, but 2 evaded. (Boeing Airplane Company)

The B-17F had an approximate empty weight of 36,135 pounds (16,391 kilograms), 40,437 pounds (18,342 kilograms) basic, and the maximum takeoff weight was 65,000 pounds (29,484 kilograms).

Aircraft mechaincs work to change a Wright Cyclone engine on the left wing of a B-17 Flying Fortress heavy bomber, circa 1944. (United States Air Force)

The B-17F was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liters) Wright Cyclone C9GC (R-1820-97) nine-cylinder radial engines with a compression ratio of 6.70:1. (Early production B-17Fs were equipped with the Wright Cyclone G666A (R-1820-65). Both variants had the same power ratings.) The engines were equipped with remote General Electric B-22 turbochargers capable of 24,000 r.p.m. The R-1820-97 was rated at 1,000 horsepower at 2,300 r.p.m. at Sea Level, and 1,200 horsepower at 2,500 r.p.m. for takeoff. The engine could produce 1,380 horsepower at War Emergency Power. 100-octane aviation gasoline was required. The Cyclones turned three-bladed, constant-speed, Hamilton-Standard Hydromatic propellers with a diameter of 11 feet, 7 inches (3.835 meters) through a 0.5625:1 gear reduction. The R-1820-97 engine is 47.80 inches (1.214 meters) long and 55.10 inches (1.399 meters) in diameter. It weighs 1,315 pounds (596 kilograms).

Boeing B-17F-130-BO Flying Fortress 42-30949, “Jumpin’ Jive.” This bomber survived the war. (U.S. Air Force)

The B-17F had a cruising speed of 200 miles per hour (322 kilometers per hour). The maximum speed was 299 miles per hour (481 kilometers per hour) at 25,000 feet (7,620 meters), though with War Emergency Power, the bomber could reach 325 miles per hour (523 kilometers per hour) at 25,000 feet for short periods. The service ceiling was 37,500 feet (11,430 meters).

With a normal fuel load of 1,725 gallons (6,530 liters) the B-17F had a maximum range of 3,070 miles (4,941 kilometers). Two “Tokyo tanks” could be installed in the bomb bay, increasing capacity by 820 gallons (3,104 liters). Carrying a 6,000 pound (2,722 kilogram) bomb load, the range was 1,300 miles (2,092 kilometers).

Most of the .50-caliber machine guns arming the B-17F Flying Fortress are visible in this photograph. (U.S. Air Force)
Many of the .50-caliber machine guns arming the B-17F Flying Fortress are visible in this photograph. (U.S. Air Force)

The B-17F Flying Fortress was armed with up to 13 air-cooled Browning AN-M2 .50-caliber machine guns. Power turrets mounting two guns each were located at the dorsal and ventral positions. A pair of machine guns were mounted in the tail, and single guns on flexible mounts were placed in the nose, radio compartment, and right and left waist positions.

A waist gunner of a B-17 with a Browning .50-caliber machine gun. Note the flight control cables, overhead, and expended cartridge casings. “Body armor saved lives. An 8th Air Force study found that body armor prevented approximately 74 percent of wounds in protected areas. Once adopted in World War II, body armor reduced the rate of wounds sustained by aircrews on missions by 60 percent. Besides saving lives, body armor boosted aircrew morale during stressful missions over enemy territory.” (U.S. Air Force)
A gunner fires the two Browning .50 caliber machine guns of his ball turret. (U.S. Air Force)
Checking the two AN-M2 Browning .50-caliber machine guns at the tail of a Boeing B-17 Flying Fortress heavy bomber, circa 1943. (Note the formation lights below the gun barrels.) LIFE Magazine)

The maximum bomb load of the B-17F was 20,800 pounds (9434.7 kilograms) over very short ranges. Normally, 4,000–6,000 pounds (1,815–2,722 kilograms) of high explosive bombs were carried. The internal bomb bay could be loaded with a maximum of eight 1,600 pound (725.75 kilogram) bombs. Two external bomb racks mounted under the wings between the fuselage and the inboard engines could carry one 4,000 pound (1,814.4 kilogram) bomb, each, though this option was rarely used.

Boeing B-17F-10-BO Flying Fortress 41-22485, Memphis Belle, in flight over England, 1943. (U.S. Air Force)
Probably the best known individual combat airplane, this is Boeing B-17F-10-BO Flying Fortress 41-22485, Memphis Belle, in flight over England, 1943. (U.S. Air Force)

The B-17 Flying Fortress first flew in 1935, and was in production from 1937 to 1945. 12,731 B-17s were built by Boeing, Douglas Aircraft Company and Lockheed-Vega. (The Manufacturer Codes, -BO, -DL and -VE, follow the Block Number in each airplane’s type designation.) 3,405 of the total were B-17Fs, with 2,000 built by Boeing, 605 by Douglas and 500 by Lockheed-Vega.

Only three B-17F Flying Fortresses remain in existence.

This restored Boeing B-17F-70-BO Flying Fortress, 42-29782, is on display at The Museum of Flight at Seattle’s Boeing Field. (Boeing)
This restored Boeing B-17F-70-BO Flying Fortress, 42-29782, (N17W) is on display at The Museum of Flight at Seattle’s Boeing Field. (Boeing)

© 2018, Bryan R. Swopes

11 December 1945

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Bell-Atlanta B-29B-60-BA Superfortress 44-84061, the Pacusan Dreamboat. (U.S. Air Force)
Bell-Atlanta B-29B-60-BA Superfortress 44-84061, the Pacusan Dreamboat. (U.S. Air Force)

11 December 1945: Three days after Lieutenant Colonel Henry E. Warden and Captain Glen W. Edwards set a transcontinental speed record flying a prototype Douglas XB-42 from Long Beach, California, to Washington, D.C., in 5 hours, 17 minutes, Colonel Clarence S. Irvine and the crew of the B-29 Pacusan Dreamboat also set a record, flying from Burbank, California to overhead Floyd Bennett Field, New York, in 5 hours, 27 minutes, 8 seconds. The average speed for the 2,464-mile flight was 450.38 miles per hour (724.82 kilometers per hour).

Lieutenant General Clarence S. Irvine, U.S. Air Force

Irvine was Deputy Chief of Staff, Pacific Air Command, 1944–1947. He flew the Pacusan Dreamboat on several record-setting flights, including Guam to Washington, D.C., and Honolulu, Hawaii to Cairo, Egypt. He rose to the rank of lieutenant general in the United States Air Force, and served as Deputy Chief of Staff for Materiel.

Pacusan Dreamboat was a Bell Aircraft Corporation B-29B-60-BA Superfortress, built at Marietta, Georgia. The B-29B was a lightweight variant of the B-29, intended for operation at lower altitudes. It did not have the four power gun turrets and their .50-caliber machine guns. A radar-directed 20 mm cannon and two .50-caliber machine guns in the tail were the only defensive weapons. Much of the standard armor plate was also deleted. Pacusan Dreamboat was further lightened. The tail guns were removed and the tail reshaped.

The B-29B was equipped with four air-cooled, fuel-injected Wright R-3350-CA-2 Duplex Cyclone two-row 18 cylinder radial engines and specially-designed propellers. The engine nacelles were modified for improved cooling.

The Superfortress had been lightened to an empty weight of 66,000 pounds (29,937 kilograms). A standard B-29B weighed 69,000 pounds (31,298 kilograms) empty and 137,000 pounds (62,142 kilograms) fully loaded. Additional fuel tanks installed on the Dreamboat were able to carry 10,000 gallons (37,854 liters) of gasoline.

Colonel Clarence S. Irvine (standing, left) with the crew of Pacusan Dreamboat: W.J.Benett, G.F.Broughton, Dock West, W.S. O’Hara, F.S. O’Leary, K.L. Royer, F.J.Shannon, J.A. Shinnault, G.R. Stanley. (FAI)
Colonel Clarence S. Irvine (standing, left) with the crew of Pacusan Dreamboat: W.J. Benett, G.F. Broughton, Dock West, W.S. O’Hara, F.S. O’Leary, K.L. Royer, F.J. Shannon, J.A. Shinnault, G.R. Stanley. (FAI)

© 2015, Bryan R. Swopes

22 November 1933

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Kalinen K-7
К-7 на аэродроме (“K-7 at the airport”), right front quarter view. (Уголок неба)

22 November 1933:

The K-7 Disaster

     On Wednesday, November 22, the Russian aircraft K-7, claimed to be the largest landplane in the world, crashed near Kharkhoff, 420 miles south-west of Moscow. Fourteen lives were lost. It is reported that M.K.A. Kalinin, the designer and director of the Kharkhoff aeroplane works, and Snegeriff, one of the best-known pilots in Russia, are among the dead. It seems that sabotage is suspected by the authorities, for the O.G.P.U. (Soviet secret police) is represented on the commission of experts investigating the disaster. Twenty trial flights had been successfully made before the crash.
 

     The design and construction of the K-7 took five years. She had a span of 208 ft., weighed about 20 tons and accommodated 120 passengers. She was considered a big stride forward in the approach to the “all-wing” aircraft, and most of the accommodation and equipment was in the wing. A few days before the accident the existence of the K-7 was revealed to the general public by “Pravda.” It was declared that the aircraft represented a “victory of the utmost political importance,” as she was constructed entirely of Soviet steel from the mills at Duiepropetrovsk. Hitherto Russia had [imported] materials for her aircraft.

—The Aircraft Engineer, Supplement to FLIGHT, 30 November 1933, at Page 1201.

The K-7 was designed by Konstantin Alekseevich Kalinin and built over a two-year period at the Kharkov State Aircraft Manufacturing Company factory at Kharkov, Ukraine. It was intended as either a heavy bomber in military service or as a civil transport. The K-7 was the largest airplane built up to that time.

К-7 в полете (“K-7 flight”) (Уголок неба)
К-7 в полете (“K-7 flight”) (Уголок неба)
Константин Алексеевич Калинин

The K-7 was an effort to perfect a “wing only” aircraft. The tail surfaces were supported by tail booms. It was operated by a crew of 11 and could carry up to 120 passengers in compartments inside the wings. The K-7 was 28.00 meters (91 feet, 10.4 inches) long with a wingspan of 53.00 meters (173 feet, 10.6 inches). The extremely large wing had an area of 254.00 meters².

As originally built the airplane was powered by six 2,896.1-cubic-inch-displacement (47.459 liter) liquid-cooled, supercharged, Mikulin AM-34 single overhead cam (SOHC) 60° V-12 engines mounted in nacelles on the leading edge of the wing. The engines were rated at 750 horsepower, each, and drove two-bladed propellers. When it was determined that power was insufficient, a seventh and then an eighth engine were added to the trailing edge in pusher configuration.

The K-7 had an empty weight of 21,000 kilograms and maximum weight of 40,000 kilograms. It’s cruise speed was 204 kilometers per hour (127 miles per hour) and the maximum speed was 234 kilometers per hour (145 miles per hour). The service ceiling was 5,500 meters (18,045 feet) and the range was 1,000 kilometers (621 miles).

In military configuration, the K-7 would be armed with 20 mm cannon and 7.62 mm machineguns. A bomb load of up to 16,000 kilograms (35,274 pounds) would be carried.

Cамолет К-7

The Kalinin K-7 made only 7 test flights before it crashed. 15 of the 20 persons aboard were killed. Kalinin was not among the dead, as had been report by Flight in the article above. One of the two tail booms failed. Some suggested that sabotage was involved. A government commission determined that the structure of the tailbooms was sufficiently strong, but that oscillations induced by aerodynamic flutter led to the failure.

During World War I, Konstantin Kalinin was awarded the Order of Sv.Stanislav. He had been given the Order of the Red Banner of Labor in 1935. However, during the Stalin purges, on 23 October 1938, he was executed as an enemy of the state.

Kalinen K-7
К-7 на аэродроме (“K-7 at the airport”), left front quarter view with engines running. (Уголок неба)

© 2018, Bryan R. Swopes

9 October 1943

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In this iconic World War II photograph, a Douglas-built B-17F-50-DL Flying Fortress, 42-3352, “Virgin’s Delight,” of the 410th Bomb Squadron, 94th Bombardment Group (Heavy), 8th Air Force, is over the Focke-Wulf Fw 190 fighter factory, Marienburg, East Prussia, 9 October 1943. The aircraft commander was Lieutenant R.E. Le Pore. (U.S. Air Force)

VIII Bomber Command Mission Number 113 was an attack by nearly 100 American heavy bombers on the Focke-Wulf Flugzeugbau AG aircraft factory at Marienburg, East Prussia (Malbork, Poland), where the Luftwaffe‘s Fw 190 fighter was being built. Early in the war, German fighter production had been dispersed and it was thought that Marienburg was beyond the range of Allied bombers.

The Fw 190 was the most effective of Germany’s fighters. More than 20,000 were built in 16 variants.

A captured Focke-Wulf Fw 190 in flight. (U.S. Air Force)
A captured Focke-Wulf Fw 190 G-3 fighter, DN+FP, W.Nr. 160016, in flight. (U.S. Air Force)
Focke-Wulf Fw 190 G-3 DN+FP, W.Nr. 160016, in flight near Wright Field, Ohio, May 1946. (U.S. Air Force)
Focke-Wulf Fw 190 G-3 DN+FP, W.Nr. 160016, from above and behind. (U.S. Air Force)

100 B-17 Flying Fortress bombers were assigned to the target and 96 of these reached the plant. Between 1253 hours and 1302 hours, the B-17s arrived over the target in five waves at 11,000 to 13,000 feet (3,353 to 3,963 meters). They dropped 217.9 tons (197.7 metric tons) of bombs with a very high degree of accuracy.

During the mission, two B-17s were lost with 13 more damaged. Three airmen were wounded and 21 listed as Missing in Action. The bomber crews claimed 9 Luftwaffe aircraft destroyed and 2 probably destroyed in air-to-air combat. Target assessment estimated that 15 Focke-Wulf Fw 190 fighters were destroyed on the ground.

This strike photo was taken from B-17 42-30353 ("Ten Knights in a Bar Room") of the 95th Bombardment Group (Heavy). (U.S. Air Force)
This strike photo was taken from Boeing B-17F-100-BO Flying Fortress 42-30353 (“Ten Knights in a Bar Room”) of the 95th Bombardment Group (Heavy). (U.S. Air Force)

Casualties among the factory work force were high. Of 669 workers, 114 were killed and 76 injured.

Air Chief Marshal Sir Charles Portal, KCB, DSO, MC, Royal Air Force, described the Marienburg attack as the “. . . most perfect example in history of the accurate distribution of bombs over a target.”

Damage assessment photograph
Reconnaissance photograph taken by a de Havilland DH.98 Mosquito PR flown by Squadron Leader R.A. Lenton and Pilot Officer Heney of No. 540 Squadron, R.A.F., 10 October 1943, showing results of the previous day’s attack. (Royal Air Force)
The target area as it appears today. (Google Maps)
"Instrument workers line up aerial cameras at Benson, Oxfordshire, before installing them in a De Havilland Mosquito PR Mark IX: (left to right) two Type F.24 (14-inch lens) vertical cameras, one F.24 (14-inch lens) oblique camera, two Type F.52 (36-inch lens) 'split pair' vertical cameras." (Imperial War Museum CH-18399)
“Instrument workers line up aerial cameras at Benson, Oxfordshire, before installing them in a De Havilland Mosquito PR Mark IX: (left to right) two Type F.24 (14-inch lens) vertical cameras, one F.24 (14-inch lens) oblique camera, two Type F.52 (36-inch lens) ‘split pair’ vertical cameras.” (Imperial War Museum CH-18399)

© 2017, Bryan R. Swopes

17 August 1942

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A flight of Boeing B-17E Flying Fortress bombers forms up over England, 1942. “Yankee Doodle,” 41-9023, is just to the left of center. (U.S. Air Force)
Brigadier General Ira C. Eaker (Margaret Bourke-White/LIFE)

17 August 1942: Mission No. 1. The United States VIII Bomber Command made its first heavy bomber attack on Nazi-occupied Europe when eighteen Boeing B-17E Flying Fortress four-engine bombers of the 97th Bombardment Group (Heavy), based at RAF Polebrook, Northamptonshire, England, headed for the railroad marshaling yards at Rouen-Sotteville, France. This was the largest and most active railroad yard in northern France.

The group began takeoffs at 1530 hours. It was escorted by several squadrons of Royal Air Force Supermarine Spitfire fighters.

While six B-17s flew along the French coast as a diversion, twelve bombers flew to Rouen and were over the target from 1739 to 1746. From an altitude of 23,000 feet (7,010 meters), they dropped 39,000 pounds (17,690 kilograms) of general purpose bombs.

Accuracy was good. One of the aim points, the locomotive shops, was destroyed by a direct hit. The overall results were moderate.

Rouen-Sotteville target assesment photograph. (U.S. Air Force)
Rouen-Sotteville target assessment photograph. (U.S. Air Force)

All of the bombers returned to their base, with the first landing at 1900. Two B-17s had been damaged. American gunners claimed damage to one Luftwaffe airplane.

brigadier General Ira C. Eaker commanded the raid from this Boeing B-17E Flying Fortress, 41-9023, Yankee Doodle, here being serviced between missions. (U.S. Air Force)
Brigadier General Ira C. Eaker commanded Mission No. 1 from this Boeing B-17E Flying Fortress, 41-9023, Yankee Doodle, shown here being serviced between missions. This bomber survived the War. (U.S. Air Force)

The raid was commanded by Brigadier General Ira C. Eaker aboard Yankee Doodle, B-17E 41-9023, leading the second flight of six B-17s. The 97th Bombardment Group Commander, Colonel Frank A. Armstrong, Jr., flew as the co-pilot of the lead ship, Butcher Shop, B-17E 41-2578, with pilot Major Paul W. Tibbets, Jr. Major Tibbets was in command of the 97th’s 340th Bombardment Squadron. (He would later command the 509th Composite Group and fly the B-29 Superfortress Enola Gay.)

Colonel Frank A. Armstrong in the pilot's position of a Boeing B-17 (Imperial War Museum, Roger Freeman Collection, Object Number FRE 890)
Colonel Frank Alton Armstrong, Jr., Air Corps, United States Army, commanding the 97th Bombardment Group (Heavy), in the pilot’s position of a Boeing B-17E Flying Fortress. (Imperial War Museum)

The Boeing B-17E Flying Fortress was a major redesign. A new aft fuselage was used, incorporating larger vertical and horizontal stabilizers. A tail turret was added. A power-operated gun turret was added at dorsal and ventral positions.

The Boeing B-17E Flying Fortress was a four-engine heavy bomber operated by a flight crew of ten. It was 73 feet, 10 inches (22.504 meters) long with a wingspan of 103 feet, 9-3/8 inches (31.633 meters) and an overall height of 19 feet, 2 inch (5.842 meters). Its empty weight was 32,350 pounds (14,674 kilograms), 40,260 pounds (18,262 kilograms) gross weight, and the maximum takeoff weight was 53,000 pounds (24,040 kilograms).

Boeing B-17E Flying Fortress 41-2587, 97th Bombardment Group, photographed 17 August 1942. (Imperial War Museum, Roger Freeman Collection, Object Number FRE 4053)
Boeing B-17E Flying Fortress 41-2578, 97th Bombardment Group, photographed 17 August 1942. (Imperial War Museum)

The B-17E was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.875 liters) Wright Cyclone G666A (R-1820-65) nine-cylinder radial engines with turbochargers, producing 1,200 horsepower at 2,500 r.p.m. for takeoff and 1,000 horsepower at 2,300 r.p.m. at Sea Level. The Cyclones turned three-bladed constant-speed Hamilton-Standard Hydromatic propellers with a diameter of 11 feet, 7 inches (3.835 meters) though a 0.5625:1 gear reduction. The R-1820-65 was 47.59 inches (1.209 meters) long and 55.12 inches (1.400 meters) in diameter. It weighed 1,315 pounds (596 kilograms). 8,422 of these engines were produced by Wright Aeronautical Division and its licensees between February 1940 and August 1942.

The B-17E had a cruise speed of 195 miles per hour (314 kilometers per hour). Its maximum speed was 318 miles per hour (512 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 36,600 feet (11,156 meters).

With a normal fuel load of 2,490 gallons (9,426 liters) the B-17E had a maximum range of 3,300 miles (5,311 kilometers). Carrying a 4,000 pound (1,814 kilogram) bomb load, the range was 2,000 miles (3,219 kilometers).

Boeing B-17E Flying Fortress 41-2578, lead ship on the 17 August 1942 air raid on Rouen-Sotteville, France. By the end of the war, this airplane was the oldest, longest-serving B-17E in the USAAF.
Boeing B-17E Flying Fortress 41-2578, the lead ship on the 17 August 1942 air raid on Rouen-Sotteville, France, flown by Major Paul W. Tibbets, photographed at RAF Bovingdon, 1943. By the end of the war, this airplane was the oldest, longest-serving B-17E in the USAAF. (Imperial War Museum)

The B-17E Flying Fortress was armed with one .30-caliber Browning M2 Aircraft Machine Gun and eight Browning AN-M2 .50-caliber machine guns. The .30 was mounted in the nose.  Power turrets mounting two .50-caliber guns, each, were located at the dorsal and ventral positions. (The first 112 B-17Es were built with a remotely-operated turret in the belly position, sighted by a periscope. A manned ball turret replaced this.) Two machine guns were in a tail turret, and one on each side at the waist.

The maximum bomb load of the B-17E was 20,800 pounds (9,435 kilograms) over very short distances. Normally, 4,000–6,000 pounds (1,815–2,722 kilograms) were carried. The internal bomb bay could be loaded with a maximum of eight 1,000 pound (454 kilogram) or four 2,000 pound (907 kilogram) bombs.

The B-17 Flying Fortress first flew in 1935, and was in production from 1937 to 1945. 12,731 B-17s were built by Boeing. 512 of the total were B-17Es. The last one was completed 28 May 1942. Production shifted to the further-improved B-17F.

Boeing B-17E Flying Fortress 41-2509, flying over the Florida Keys, circa 1942. (Getty Images)

© 2017, Bryan R. Swopes