Tag Archives: Wright Cyclone G666A

17 May 1943

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)

17 May 1943: The flight crew of the B-17 Memphis Belle completed their combat tour of 25 bombing missions over Western Europe with an attack on the massive Kéroman Submarine Base at Lorient, France.¹ The bomber was a U.S. Army Air Force Boeing B-17F-10-BO Flying Fortress, serial number 41-24485, assigned to the 324th Bombardment Squadron (Heavy), 91st Bombardment Group (Heavy), VIII Bomber Command, based at Air Force Station 121 (RAF Bassingbourne, Cambridgeshire, England). The aircraft commander was Captain Robert Knight Morgan, Air Corps, United States Army.

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 Memphis Belle was only the second B-17 to survive 25 missions, so it was withdrawn from combat and sent back to the United States for a publicity tour.

Miss Margaret Polk
Miss Margaret Polk

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. ² (Morgan named his next airplane—a B-29 Superfortress—Dauntless Dotty, after his wife, Dorothy Grace Johnson 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.

B-17F-10-BO Flying Fortress 41-24485 (c/n 3190) was built by the Boeing Aircraft Company at its Plant 2 in Seattle, Washington, during the summer of 1942. It was the 195th airplane in the B-17F series, and one of the third production block. Flown by a Boeing pilot named Johnston, the new bomber made its first flight, 1 hour, 40 minutes, on 13 August 1942. Maintenance records indicate, “1st flight OK.”

The B-17 was flown to Bangor, Maine and on 31 August 1942 was assigned to the 324th Bombardment Squadron (Heavy), 91st Bombardment Group (Heavy), then preparing to deploy overseas.

2nd Lieutenant Morgan first flew 41-24485 on 3 September, and logged nearly 50 hours over the next three weeks. The squadron flew across the North Atlantic Ocean, and 41-24485 arrived at its permanent station, Bassingbourne, on 26 October 1942.

Following its twenty-fifth combat mission, Memphis Belle was flown back to the United States on 9 June 1943.

After the war, Memphis Belle was 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, Dayton, Ohio, where it has been undergoing a total restoration for the last several years.

Survivors. The crew of the Memphis belle after their 25th combat mission, 17 May 1943. (U.S. Air Force)
Survivors. The crew of the Memphis Belle after their 25th combat mission, 17 May 1943. (U.S. Air Force)

The Boeing B-17F Flying Fortress was a four-engine heavy bomber operated by a flight crew of ten. It was 74 feet, 9 inches (22.784 meters) long with a wingspan of 103 feet, 9.375 inches (31.633 meters) and an overall height of 19 feet, 1 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 B-17F was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liters) Wright Cyclone G666A (R-1820-65) ³ 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).

Boeing B-17F-10-BO Flying Fortress 41-22485, Memphis Belle, in flight over England, 1943. (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).

The original “Petty Girl” pin-up nose art of the B-17 bomber, “Memphis Belle,” during restoration.

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.

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.

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

Only three B-17F Flying Fortresses, including Memphis Belle, remain in existence. The completely restored bomber goes on public display at the National Museum of the United States Air Force, today, 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 VIII Bomber Command Mission No. 58

² The nose art was painted by Corporal Anthony L. Starcer.

³ Later production B-17F and B-17G bombers were equipped with Wright Cyclone C9GC (R-1820-97) engines.

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)

© 2018, Bryan R. Swopes

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17 August 1942

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. 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. (United States Air Force via Getty Images)

© 2017, Bryan R. Swopes

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