Tag Archives: Bomber

26 June 1948

Convair B-36A-1-CF (S/N 44-92004, the first -A model built) in flight. (U.S. Air Force photo)
Convair B-36A-1-CF 44-92004, the first B-36A built. (U.S. Air Force)

26 June 1948: The 7th Bombardment Wing, Very Heavy, at Carswell Air Force Base, Fort Worth, Texas, received the United States Air Force’s first Consolidated-Vultee Aircraft Corporation (“Convair”) B-36A, a six-engine, very long range heavy bomber. Its mission was to serve as a nuclear-capable deterrent until the Boeing B-52 Stratofortress came into service five years later. A total of 22 B-36As were delivered by February 1949. These were not armed and were used for crew training. Most were later converted by Convair to RB-36E reconnaissance bombers, beginning in 1950.

The B-36A differed from the XB-36 prototype in several areas, but two features were the most apparent: The cockpit had been completely revised and now covered by a large dome. The single-wheel main landing gear was replaced by four-wheel bogies to better spread the airplane’s weight over the runway surface.

A crew of thirteen airmen with their Convair B-36A-10-CF Peacemaker, 44-92014. (LIFE Magazine via Jet Pilot Overseas)
A crew of thirteen airmen with their Convair B-36A-10-CF Peacemaker, 44-92013, at Carswell AFB, 1949. (LIFE Magazine via Jet Pilot Overseas)

The B-36A was 162.1 feet (49.4 meters) long with a wingspan of 230.0 feet (70.1  meters) and overall height of 46.8 feet (14.3 meters). The wings had 2° dihedral, an angle of incidence of 3° and -2° twist. The wings’ leading edges were swept aft to 15° 5′. The airplane’s total wing area was 4,772 square feet (443.33 square meters). Its empty weight was 135,020 pounds (61,244 kilograms). The combat weight was 212,800 pounds (96,524 kilograms) and maximum takeoff weight (MTOW) was 310,380 pounds (140,786 kilograms).

Convair B-36A 44-92015 at Carswell Air Force Base, 26 June 1948.

The initial production version of the Peacemaker was powered by six air-cooled, supercharged, 4,362.5 cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major R-4360 Pusher (R-4360-25) four-row, 28-cylinder radial engines rated at 2,500 horsepower at 2,550 r.p.m. at 37,000 feet (11,278 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. Each engine drove a 19-foot (5.791 meter) three-bladed propeller through a 0.381:1 gear reduction. The R-4360-25 was 9 feet, 1.75 inches (2.788 meters) long and 4 feet, 4.50 inches (1.334 meters) in diameter. It weighed 3,483 pounds (1,580 kilograms).

Convair B-36A 44-92015

The six radial engines gave the bomber a maximum speed of 300 knots (345 miles per hour/556 kilometers per hour) at 31,600 feet (9,632 meters). It took 53 minutes for the giant airplane to climb to an altitude of 20,000 feet (6,396 meters). The service ceiling for the B-36A was 39,100 feet (11,918 meters), and combat ceiling was 35,800 feet (10,912 meters). The ferry range was 9,136 miles (14,702 kilometers).

The B-36As initially carried no defensive armament. The maximum bomb load was seventy-two 1,000 pound bombs (total, 72,000 pounds/32,659 kilograms) carried in four internal bomb bays. With a bomb load of 10,000 pounds (4,536 kilograms), the B-36A had a combat radius of 3,370 nautical miles (3,878 miles/6,241 kilometers).

Designed during World War II when nuclear weapons were unknown to aeronautical engineers, the bomber was designed to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs. It could carry a single 43,600 pound (19,777 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or, later, several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 15-megaton thermonuclear bomb could be carried.

The sixteenth B-36A, 44-92020, after conversion to the RB-36E reconnaissance configuration. (U.S. Air Force)
The sixteenth B-36A, 44-92020, after conversion to the RB-36E reconnaissance configuration. (U.S. Air Force)

The RB-36E reconnaissance bomber carried a crew of 22. The radial engines were upgraded to R-4360-41s which increased takeoff horsepower with water injection to 3,500 at 2,700 r.p.m. at Sea Level. Four General Electric J47-GE-19 turbojet engines were added in two two-engine pods at the outer end of each wing. These changes significantly increased the airplane’s maximum speed and altitude capability and reduced the required takeoff distance by 25%. Fourteen reconnaissance cameras were installed. There were four additional radomes on the belly and numerous external antennas for electronic intelligence gathering.

The empty weight of the RB-36E increased to 164,238 pounds (74,497 kilograms) and the maximum takeoff weight to 370,000 pounds (167,829 kilograms).

The maximum speed of the RB-36E was 363 knots (418 miles per hour/672 miles per hour) at 38,200 feet (11,643 meters). Its service ceiling was 46,400 feet (14,143 meters).

The reconnaissance bomber carried eighty 188 pound (85.3 kilogram) T-56 photo flash bombs. Defensive armament consisted of sixteen M24A1 20 mm autocannon in five remotely-operated turrets. 9,200 rounds of ammunition were carried.

Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.

The first Consolidated-Vultee B-36A, 44-92004, was flown to Wright Field, Dayton, Ohio, for structural testing. Redesignated YB-36A, it was tested to destruction.

Convair YB-36 (B-36A) 004 under structural testing at Wright Field. (U.S. Air Force)
Convair YB-36A 44-92004 under structural testing at Wright Field. (U.S. Air Force)

The name, “Peacemaker,” was suggested by a Convair employee. It is a reference to the Colt Model 1873 Single-Action Army® revolver, the classic “six-shooter” of the American frontier, which is also known as the Peacemaker®.

© 2018, Bryan R. Swopes

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25 June 1946

Northrop XB-35 taking of at Northrop Field, Hawthorne, California. (U.S. Air Force)
Northrop XB-35 taking off at Northrop Field, Hawthorne, California. (U.S. Air Force)
Max R. Stanley (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers))

25 June 1946: Northrop Aircraft, Inc., experimental test pilot Max R. Stanley and flight engineer Dale Schroeder made the first flight of the Northrop XB-35 “Flying Wing,” serial number 42-13603. They took off from the factory’s airfield at Hawthorne, California, and flew the prototype bomber to Muroc Army Air Field (now, Edwards Air Force Base). The initial flight lasted 55 minutes.

The Los Angeles Times reported:

On June 25, 1946, Stanley piloted the first Flying Wing, the B-35, which was a four-engine 172-foot-long, boomerang-shaped craft, from Northrop’s Hawthorne Airport to what was then the Muroc Army airfield east of Palmdale.

Emerging from the cockpit after the 55-minute flight, Stanley told The Times: “She handled beautifully.”

But taxiing along the rabbit-infested Hawthorne runway, he had had momentary doubts, he conceded 50 years later: “I looked out and I was not gaining speed on this rabbit. I thought, either something’s wrong or that’s one hell of a fast rabbit.”

Flight test crew of Northrop's XB-35 at Northrop Field, Hawthorne, California, 1946.
The flight test crew of the Northrop XB-35 at Northrop Field, Hawthorne, California, 1946. Max Stanley is just to the left of center. (Unattributed)

The XB-35 was designed as an aerodynamically efficient heavy bomber. It had a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament was contained within the wing. It was 53 feet, 1 inch (16.180 meters) long, with a wingspan of 172 feet (52.426 meters) and overall height of 20 feet, 1 inch (6.121 meters). The prototype weighed 89,560 pounds (40,624 kilograms) empty, with a gross weight of 180,000 pounds (81,647 kilograms).

The Wing defined the airplane. It had an aspect ratio of 7.4:1. The wing’s root chord was 37 feet, 6 inches (11.430 meters). The wing was 7 feet, 1.5 inches (2.172 meters) thick at the root. The tip chord was 9 feet, 4 inches (2.844 meters). There was 0° angle of incidence at the root, with -4° of twist, and 0° 53′ dihedral. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters).

This view of the Northrop XB-35 Flying W 42-13603 on the ramp at Muroc Air Force Base shows the pusher arrangement of four-bladed contra-rotating propellers. In the background, a turbojet-powered YB-49 is in a right bank.. (U,S. Air Force)
This view of the first prototype Northrop XB-35, 42-13603, the “Flying Wing,” on the ramp at Muroc Air Force Base shows the pusher arrangement of four-bladed contra-rotating propellers. In the background, a turbojet-powered Northrop YB-49 is in a steep bank. (U.S. Air Force)

The XB-35 was powered by four air-cooled, supercharged and turbocharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major TSB1P-RGD (R-4360-17 or  -21) four-row 28-cylinder radial engines with a compression ratio of 7:1. The R-4360-17 was rated at 2,500 horsepower at 2,550 r.p.m at 40,000 feet (12,192 meters), and 3,000 horsepower at 2,700 r.p.m., for takeoff. It could maintain the takeoff rating to an altitude of 40,000 feet (12,192 meters) for Military Power. The engines were mounted completely inside the wing and were connected to a remote propeller drive unit by drive shafts. The engines were direct drive, while the propeller gear boxes had a 0.381:1 reduction ratio. The R-4360-17 was 5 feet, 7.00 inches (1.702 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,306 pounds (1,499.6 kilograms).

Northrop XB-35 42-13603 in flight with early contra-rotating propellers. (U.S. Air Force)

The propellers were dual three-bladed contra-rotating assemblies located in pusher configuration at the wing’s trailing edge. (These were quickly changed to four-bladed propellers, which were smoother in operation and more efficient.)

Northrop XB-35 42-13603. (U.S. Air Force)
Northrop XB-35 42-13603. (U.S. Air Force)

The XB-35 had a cruising speed of 183 miles per hour (295 kilometers per hour) at 39,700 feet (12,100 meters) and maximum speed was 391 miles per hour (629 kilometers per hour) at 35,000 feet (10,668 meters). With a crew of nine, and another six relief crewmembers, the bomber had a range of 8,150 miles (13,116 kilometers).

The production Northrop B-35 would have been armed with twenty .50-caliber machine guns for defense and a maximum bomb load of 51,200 pounds (23,223 kilograms).

The XB-35 was plagued by unresolved problems with the propeller gear boxes which eventually forced Jack Northrop to ground the aircraft until the engine and propeller manufacturers could come up with a solution, which was to change from piston to turbojet engines. That version became the YB-49. Because of the continuing problems, though, 42-13603 was grounded after only 19 flights, and with its sister ship, XB-35 42-38323, was scrapped in August 1949.

Northrop XB-35 in flight. (U.S. Air Force)
A Northrop XB-35 in flight. (U.S. Air Force)

© 2018, Bryan R. Swopes

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22 June 1962

The last of 744 Boeing B-52 Stratofortress bombers, B-52H-175-BW, 61-0040, is rolled out at the Boeing plant at Wichita, Kansas. (Boeing)
The last of 744 Boeing B-52 Stratofortress bombers, B-52H-175-BW, 61-0040, is rolled out at the Boeing plant at Wichita, Kansas. (Boeing)

22 June 1962: The last of 744 Boeing B-52 Stratofortress strategic bombers, B-52H-175-BW, serial number 61-0040, was rolled out at the Boeing Military Airplane Company plant in Wichita, Kansas.

The U.S. Air Force contracted 62 B-52H Stratofortresses, serial numbers 60-0001 through 60-0062, on 6 May 1960. A second group of 40, serials 61-0001 through 61-0040, were ordered later. All were built at the Boeing Wichita plant.

The B-52H, like the B-52G, is a re-engineered aircraft, structurally different from the XB-52, YB-52, and B-52A–B-52F Stratofortress variants. It is lighter, carries more internal fuel, giving it a longer unrefueled range, and is strengthened for low-altitude flight. The shorter vertical fin is intended to prevent the losses caused by the original tall fin in turbulent air. The B-52H is equipped with quieter, more efficient turbofan engines.

Boeing B-52H-175-BW Stratofortress 61-0040 in camouflage. (U.S. Air Force)
Boeing B-52H-175-BW Stratofortress 61-0040 in camouflage, assigned to 2nd Air Force, circa 1975. (U.S. Air Force)

The B-52H was developed to carry four Douglas GAM-87 Skybolt air-launched ballistic missiles on pylons mounted under the wings, inboard of the engines. The Skybolt was armed with a 1-megaton W-59 thermonuclear warhead. The program was cancelled, however, and the North American Aviation AGM-28 Hound Dog air-launched cruise missile was used instead. (Interestingly, the Hound Dog’s Pratt & Whitney J52-P-3 turbojet engine could be used to supplement the B-52’s takeoff thrust, and then refueled from the bomber’s tanks before being air-launched.)

The B-52H is a sub-sonic, swept wing, long-range strategic bomber. It was originally operated by a crew of six: two pilots, a navigator and a radar navigator, an electronic warfare officer, and a gunner. (The gunner was eliminated after 1991). The airplane is 159 feet, 4 inches (48.565 meters) long, with a wing span of 185 feet (56.388 meters). It is 40 feet, 8 inches (12.395 meters) high to the top of the vertical fin. The B-52H uses the vertical fin developed for the B-52G, which is 22 feet, 11 inches (6.985 meters) tall. This is 7 feet, 8 inches (2.337 meters) shorter than the fin on the XB-52–B-52F aircraft, but the fin’s chord is longer.

The wings of the B-52H have a total area of 4,000 square feet ( square meters). The leading edges are swept aft to 36° 58′. The angle of incidence is 6°, and there is 2° 30′ dihedral. (The wings are very flexible and exhibit pronounced anhedral when on the ground.) To limit twisting in flight, the B-52 has spoilers on top of the wings rather than ailerons at the trailing edges.

Boeing B-52H Stratofortress. (U.S. Air Force)

The bomber has an empty weight of 172,740 pounds (78,354 kilograms) and its Maximum Takeoff Weight (MTOW) is 488,000 pounds (221,353 kilograms).

The most significant difference between the B-52H and the earlier Stratofortresses is the replacement of the eight Pratt & Whitney J57-series turbojet engines with eight Pratt & Whitney Turbo Wasp JT3D-2 (TF33-P-3) turbofans, which are significantly more efficient. They are quieter and don’t emit the dark smoke trails of the turbojets. The TF-33 is a two-spool axial-flow turbofan engine with 2 fan stages, a 14-stage compressor section (7-stage intermediate pressure, 7-stage high-pressure) and and a 4-stage turbine (1-stage high-pressure, 3-stage low-pressure). The TF33-P-3 has a maximum continuous power rating of 14,500 pounds of thrust (64.499 kilonewtons) at 9,750 r.p.m., N1. Military Power, limited to 30 minutes, is 16,500 pounds (73.396 kilonewtons) at 10,000 r.p.m., N1. Each engine produces a maximum of 17,000 pounds of thrust (75.620 kilonewtons) at 10,050 r.p.m., N1, with a 5-minute limit. The TF33-P-3 is 11 feet, 4.32 inches (3.4625 meters) long, 4 feet, 4.93 inches (1.3442 meters) in diameter and weighs 3,900 pounds (1,769 kilograms).

The B-52H has a cruise speed of 456 knots (525 miles per hour/845 kilometers per hour). It has a maximum speed, with Military Power, of 555 knots (639 miles per hour/1,028 kilometers per hour) at 20,700 feet (6,309 meters)—0.906 Mach. The service ceiling is 46,900 feet (14,295 meters). The unrefueled range is 8,000 miles (12,875 kilometers). With inflight refueling, its range is limited only by the endurance of its crew.

A Boeing B-52H Stratofortress during a deterrent patrol near the Democratic People's Republic of North Korea, 2016. (U.S. Air Force)
A Boeing B-52H Stratofortress during a deterrent patrol near the Democratic People’s Republic of North Korea, 2016. (U.S. Air Force)

The B-52H can carry a wide variety of conventional free-fall or guided bombs, land-attack or anti-ship cruise missiles, and thermonuclear bombs or cruise missiles. These can be carried both in the internal bomb bay or on underwing pylons. The bomb load is approximately 70,000 pounds (31,751 kilograms).

The B-52H was equipped with a General Electric M61 Vulcan 20 mm six-barreled rotary cannon (a “Gatling gun”) in a remotely-operated tail turret. The gun had a rate of fire of 4,000 rounds per minute, and had a magazine capacity of 1,242 rounds. After 1991, the gun and its radar system were removed from the bomber fleet. The flight crew was reduced to five.

The B-52H was armed with a 20 mm M61 Vulcan 6-barreled cannon in place of the four .50-caliber machine guns of the earlier variants.
The B-52H was armed with a 20 mm M61 Vulcan 6-barreled cannon in place of the four .50-caliber machine guns of the earlier variants.

102 B-52Hs were built by Boeing Wichita. Beginning in 2009, eighteen B-52H bombers were placed in climate-controlled long term storage at Tinker Air Force Base, Oklahoma.  In 2014, the entire fleet began a major avionics upgrade. As of December 2015, fifty-eight of the bombers remained in the active fleet of the United States Air Force and eighteen are assigned to the Air Force Reserve.

Recently, a B-52H-156-BW Stratofortress, 61-0007, Ghost Rider, was returned to operational status after eight years in storage at Davis-Monthan Air Force Base, Tucson, Arizona. 45,000 man-hours were required to restore the bomber.

The B-52H is expected to remain in service until 2040.

56 years after roll-out, 61-0040 is still in service with the United States Air Force, assigned to the 23rd Bomb Squadron, 5th Bomb Wing at Minot Air Force Base, North Dakota.

Boeing B-52H-175-BW Stratofortress 61-0040 parked at Anderson Air Force Base, Guam. (U.S. Air Force)
Boeing B-52H-175-BW Stratofortress 61-0040 parked at Andersen Air Force Base, Guam. (U.S. Air Force)

© 2019, Bryan R. Swopes

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13 June 1943

USAAF Boeing B-17F Flying Fortress with left outboard engine on fire and right wing shot off, out of control and going down over Europe, World War II. (U.S. Air Force)

13 June 1943: On Mission Number 63, 76 VIII Bomber Command Boeing B-17F Flying Fortress four-engine heavy bombers of the 4th Bombardment Wing were sent to attack the U-boat pens at Kiel, Germany.

An Allied merchant convoy formed up to cross the Atlantic Ocean, 1942. (Naval Supply Corps Newsletter/Library of Congress)

German submarine attacks on transatlantic convoys were a major threat to the Allies. England was dependent on North America for food, fuel, munitions and weapons. Destruction of the submarine bases and repair facilities was therefore a very high priority for VIII Bomber Command. These were often very heavily reinforced concrete bunkers where submarines could be serviced and repaired, safe from air attack.

The “Kilian” base at Kiel was for the protection of up to 12 newly-built U-boats. Each bay was 138 meters (453 feet) long and could house two submarines, end-to-end. The roof was 4.8 meters (15 feet, 9 inches) of reinforced concrete, and the walls were 3.3 meters (10 feet, 10 inches) thick.

U-Boot Typ VII C im Bunkerdock. (L.-G. Buchheim © Buchheim Stiftung)

60 bombers made it to the target but were met with the heaviest fighter attacks to that point of the war. 22 B-17s were shot down. Of those that returned to England, 24 were damaged, 1 so badly that it was beyond repair.

3 airmen were killed, 20 wounded and 213 were listed as Missing In Action.

Before the war, it was thought that the defensive machine guns of the Flying Fortress would be able to protect it against enemy fighters, but losses like those suffered in this raid proved the necessity for escorting fighters to defend the bomber formations.

NOTE: A very detailed analysis of this mission, “USAAF Mission #63: Bremen and Keil” by Andreas Zapf can be found at

http://www.andreaszapf.de/blog-chronicles-media/USAAF-Mission-63-Bremen-and-Kiel.pdf 

U-boat pen
U-boat pen

© 2018, Bryan R. Swopes

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9 June 1943

Boeing B-17F-10-BO Flying Fortress 41-24485, Memphis Belle, flies home from England, 9 June 1943. (U.S. Air Force)

9 June 1943: After completing 25 combat missions over Western Europe from its base at Air Force Station 121 (RAF Bassingbourne, Cambridgeshire, England), Memphis Belle, a U.S. Army Air Forces Boeing B-17F-10-BO Flying Fortress, serial number 41-24485, assigned to the 91st Bombardment Group (Heavy), 324th Bomb Squadron (Heavy), was flown home by Captain Robert K. Morgan and Captain James A. Verinis.

The crew of the Memphis Belle after their 25th mission: (left to right) Technical Sergeant Harold Loch, Top Turret Gunner/Engineer; Staff Sergeant Cecil Scott, Ball Turret Gunner; Technical Sergeant Robert Hanson, Radio Operator; Captain James Verinis, Co-pilot; Captain Robert Morgan, Aircraft Commander/Pilot; Captain Charles Leighton, Navigator; Staff Sergeant John Quinlan, Tail Gunner; Staff Sergeant Casimer Nastal, Waist Gunner; Captain Vincent Evans, Bombardier; Staff Sergeant Clarence Winchell Waist Gunner. (U.S. Air Force photograph)

The daylight bombing campaign of Nazi-occupied Europe was very dangerous with high losses in both airmen and aircraft. For a bomber crew, 25 combat missions was a complete tour, and they were sent on to other assignments. Memphis Belle was only the second B-17 to survive 25 missions, so it was withdrawn from combat and sent back to the United States for a publicity tour.

Boeing B-17F-10-BO Flying Fortress 41-22485, Memphis Belle, in flight over England, 1943. (U.S. Air Force)
Miss Margaret Polk, 1943.

The B-17’s name was a reference to Captain Morgan’s girlfriend, Miss Margaret Polk, who lived in Memphis, Tennessee. The artwork painted on the airplane’s nose was a “Petty Girl” based on the work of pin-up artist George Petty of Esquire magazine. (Morgan named his next airplane—a B-29 Superfortress—Dauntless Dotty after his wife, Dorothy Morgan. With it, he led the first B-29 bombing mission against Tokyo, Japan, in 1944. It was also decorated with a Petty Girl.)

Memphis Belle and her crew were the subject of a 45-minute documentary, “Memphis Belle: A Story of a Flying Fortress,” directed by William Wyler and released in April 1944. It was filmed in combat aboard Memphis Belle and several other B-17s. The United States Library of Congress named it for preservation as a culturally significant film.

After returning to the United States, Memphis Belle was sent on a War Bonds tour. In this photograph, it is parked at Patterson Field, Dayton, Ohio. (U.S. Air Force)

Following the War Bonds tour, Memphis Belle was assigned to MacDill Field, Tampa, Florida, where it was used for combat crew training.

Boeing B-17F Flying Fortress 41-224485, “Memphis Belle,” arrives at the NACA Aircraft Engine Research Laboratory at Lewis Field, Cleveland, Ohio, 7 July 1943. (NASA)

After the war, Memphis Belle was sent to a “boneyard” at Altus, Oklahoma, to be scrapped along with hundreds of other wartime B-17s. A newspaper reporter learned of this and told Memphis’ mayor, Walter Chandler. Chandler purchased it for its scrap value and arranged for it to be put on display in the city of Memphis. For decades it suffered from time, weather and neglect. The Air Force finally took the bomber back and placed it in the permanent collection of the National Museum of the United States Air Force at Wright-Patterson Air Force Base, where it has been undergoing a total restoration for the last several years.

“On July 17, 1946, at 2:55 p.m., the Memphis Belle rolled to a stop in front of the Administration Building at Municipal Airport and ended its final flight. The plane had been stored in Altus, Okla. Mayor Walter Chandler (fifth left in white suit) and some 200 people greeted the Belle and the final flight’s crew (from left) Stuart Griffin, radioman; Lt. James Gowdy, navigator; Capt. Hamp Morrison, co-pilot; Capt. Robert Little, pilot; Sgt. Percy Roberts Jr., engineer; Capt Robert Taylor, co-navigator and Tech Sgt. Charles Crowe, engineer. (Editor’s Note: This crew was the crew that flew the plane from Altus, Okla.; not the wartime flight crew)” (The Commercial Appeal)

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, 9.38 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).

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).

The forward fuselage of Memphis Belle dismantled for restoration at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton Ohio. The “Petty Girl” on the right side of the airplane is in red. (U.S. Air Force)

The B-17F was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liters) Wright Cyclone G666A (R-1820-65)¹ nine-cylinder radial engines with a compression ratio of 6.70:1. The engines were equipped with remote General Electric turbochargers capable of 24,000 r.p.m. The R-1820-65 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) though a 0.5625:1 gear reduction. The R-1820-65 engine is 3 feet, 11.59 inches (1.209 meters) long and 4 feet, 7.12 inches (1.400 meters) in diameter. It weighs 1,315 pounds (596 kilograms).

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).

Boeing B-17F-10-BO Flying Fortress 41-24485, the Memphis Belle, under restoration at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio. (U.S. Air Force)

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).

The Memphis Belle was armed with 13 Browning AN-M2 .50-caliber machine guns for defense against enemy fighters. Power turrets mounting two guns each were located at the dorsal and ventral positions. Four machine guns were mounted in the nose, 1 in the radio compartment, 2 in the waist and 2 in the tail.

Restoration of the B-17 Flying Fortress Memphis Belle progresses. (Air Force Times)

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.

The B-17 Flying Fortress was in production from 1936 to 1945. 12,731 B-17s were built by Boeing, Douglas Aircraft Company and Lockheed-Vega. (The manufacturer codes -BO, -DL and -VE follows 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, including Memphis Belle, remain in existence. The completely restored bomber went on public display at the National Museum of the United States Air Force, 17 May 2018.

Boeing B-17F-10-BO Flying Fortress 41-24485, “Memphis Belle,” photographed 14 March 2018 at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio. (U.S. Air Force)

Memphis Belle ® is a Registered Trademark of the United States Air Force.

¹ Later production B-17F and B-17G bombers were equipped with Wright Cyclone C9GC (R-1820-97) engines.

© 2018, Bryan R. Swopes

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