Tag Archives: Pratt & Whitney Twin Wasp S3C4-G

30 June 1975

The last operational U.S. Air Force C-47 Skytrain, 43-49507, on display at NMUSAF. (U.S. Air Force)

30 June 1975: The last operational Douglas C-47 Skytrain transport in service with the United States Air Force, 43-49507, was retired and flown to the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Ohio.

A C-47D, it is on display in the World War II Gallery, painted and marked as C-47A-80-DL 43-15213 of the 91st Troop Carrier Squadron, 439th Troop Carrier Group, during World War II. At the time it was withdrawn from service, 43-49507 had flown a total of 20,831 hours.

43-49507 (Douglas serial number 26768) was built at Oklahoma City as a C-47B-15-DK Skytrain. The C-47B differed from the C-47A in that it was powered by Pratt & Whitney Twin Wasp S3C4-G (R-1830-90) engines. These engines were equipped with two-speed superchargers for improved high-altitude performance. Following World War II, the second speed (“high blower”) was either disabled or removed. Following this modification, the airplane was redesignated C-47D.

A group of new Douglas C-47 Skytrains. The airplane closest to the camera is C-47-DL 41-18415. (Douglas Aircraft Company)

The Douglas C-47 Skytrain is a military transport variant of the Douglas Aircraft Company DC-3 commercial airliner. It is an all-metal, twin-engine, low-wing monoplane with retractable landing gear. It was operated by a minimum flight crew of two pilots, navigator, radio operator and mechanic/load master. The airplane’s control surfaces are covered with doped-fabric. The primary differences between the civil DC-3 and military C-47 was the addition of a cargo door on the left side of the fuselage, a strengthened cargo floor, a navigator’s astrodome and provisions for glider towing.

The DC-3 made its first flight 17 December 1935, while the C-47 flew for the first time six years later, 23 December 1941.

Two Douglas C-47 Skytrains. Nearest the camera is C-47A-90-DL 43-15661. The further airplane is C-47A-65-DL 42-100550. (U.S. Air Force)

The C-47 is 64 feet, 5½ inches (19.647 meters) long with a wingspan of 95 feet (28.956 meters) and height of 17 feet (5.182 meters). The total wing area is 988.9 square feet (91.872 square meters). The angle of incidence is 2°. The wing center section is straight, but outboard of the engine nacelles there is 5º dihedral. The wings’ leading edges are swept aft 15.5°. The trailing edges have no sweep.  Empty weight of the C-47D is 17,865 pounds (8,103 kilograms) and the maximum takeoff weight is 33,000 pounds (14,969 kilograms).

The C-47A was powered by two 1,829.4-cubic-inch-displacement (29.978 liter) air-cooled, supercharged R-1830-92 (Pratt & Whitney Twin Wasp S1C3-G) two-row 14-cylinder radial engines with a compression ratio of 6.7:1. These were rated at 1,060 horsepower at 2,550 r.pm., up to 7,500 feet (2,286 meters), maximum continuous power, and 1,200 horsepower at 2,700 r.p.m. at Sea Level for takeoff. Each engine drives a three-bladed Hamilton Standard Hydromatic constant-speed full-feathering propeller with a diameter of 11 feet, 6 inches (3.505 meters) through a 16:9 gear reduction. The R-1830-92 is 48.19 inches (1.224 meters) long, 61.67 inches (1.566 meters) in diameter, and weighs 1,465 pounds (665 kilograms).

U.S. Army paratroopers jump from Douglas C-47-DL Skytrain 41-7805, over England, May 1944. (U.S. Air Force)

The specifications of the  Pratt & Whitney Twin Wasp S3C4-G (R-1830-90) installed on the C-47B and C-47D were nearly the same as the -92 engine of the C-47A. Displacement and compression ratio were identical. The engines’ diameters were the same, though the -90 was very slightly longer than the -92—1.85–2.74 inches (4.699–6.960 centimeters), depending on specific variant. Also, the -90 was heavier than the -92 by 25–30 pounds (11.34–13.61 kilograms), again, depending on the specific variant. The R-1830-90 could maintain 1,000 horsepower at 2,550 r.p.m. at 12,500 feet (3,810 meters), and 1,000 horsepower at 2,700 r.p.m. at 14,000 feet (4,267 meters), a significant increase over the -92.

The C-47D has a cruising speed of 161 knots (185 miles per hour/298 kilometers per hour) at 10,000 feet (3,048 meters), and maximum speed of 202 knots (232 miles per hour/374 kilometers per hour) at 3,500 feet (1,067 meters). Its service ceiling was 22,150 feet (6,751 meters). The Skytrain had a maximum range of 1,026 nautical miles (1,181 miles/1,900 kilometers) with full cargo.

The C-47 could carry 9,485 pounds (4,302 kilograms) of cargo, or 27 fully-equipped paratroopers. Alternatively, 24 patients on stretchers could be carried, along with two attendants.

C-47 Skytrains in Vee-of Vees formation.

On D-Day, The Sixth of June, 1944, a formation of C-47 Skytrains, nine airplanes abreast, 100 feet (30 meters) from wing tip to wing tip, 1,000 feet (305 meters) in trail, stretching for over 300 miles (483 kilometers), airdropped 13,348 paratroopers of the 82nd and 101st Airborne Divisions, United States Army, and another 7,900 men of the British Army 6th Airborne Division and the 1st Canadian Parachute Battalion, behind the beaches at Normandy, France.

During the Vietnam War, 53 C-47s were converted from their transport role to AC-47 Spooky gunships. These were armed with three fixed, electrically-powered General Electric  GAU-2/A .30-caliber (7.62 NATO) Gatling guns firing out the left side of the fuselage. These aircraft were highly effective at providing close air support. The three Miniguns could fire a total of 12,000 rounds per minute.

Douglas AC-47D Spooky gunship, 45-0927, 4th Special Operations Squadron, Nha Trang, Republic of Vietnam, September 1968. (U.S. Air Force)

Douglas Aircraft Company built 10,174 C-47 Skytrains at its factories in Santa Monica and Long Beach, California, and at Oklahoma City, Oklahoma.

Douglas DC-3 (C-47B) three-view drawing. (NASA)

© 2018, Bryan R. Swopes

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2 June 1941

Consolidated Aircraft Corporation Model LB-30, Liberator B Mk.II, AL503 (SDASM Archives)

2 June 1941: Great Britain had been at war with Germany for 21 months. Its need for military equipment far exceeded the capacity of British industry, so the Empire looked across the North Atlantic Ocean to its former colonies, the United States of America.

The Royal Air Force ordered 140 Liberator B Mk.II bombers from Consolidated Aircraft Corporation of San Diego, California. The Consolidated Model LB-30 was a variant of the U.S. Army Air Corps B-24 four-engine long-range heavy bomber, but was built expressly for the RAF and had no direct Air Corps equivalent.

AL503 was the first Liberator Mk.II. It had made its first flight 26 May 1941, and was ready to be turned over to the Royal Air Force.

AL503 crashed on its acceptance flight, 2 June 1941. The aircraft was destroyed and all five on board were killed.

Consolidated LB-32, Liberator B Mk.II, AL503, photographed 2 June 1941—the same day it crashed. (Consolidated Aircraft Corporation)
Consolidated Model LB-30, Liberator B Mk.II, AL503, photographed 2 June 1941—the same day it crashed. The four-gun upper turret is visible. The bomb bay is open. (Consolidated Aircraft Corporation)

The Associated Press reported the accident:

Big Bomber Made for Britain Crashes in San Diego Bay; Four Members of Crew Perish

SAN DIEGO, Calif., June 2—(AP)—A $250,000 four-motored Consolidated bomber crashed and sank in San Diego Bay today, shortly after taking off from Lindbergh Field. Consolidated Aircraft Corp. officials said four of the crew members apparently perished.

The 25-ton craft was camouflaged and ready for delivery to Great Britain.

William B. Wheatley, 39, Chester, N.Y., chief test pilot for the Consolidated Aircraft Corp., apparently was at the controls. The Navy had taken over rescue operations, and details and names of crew members were not immediately available.

Witnesses said the huge plane left the airport on what appeared to be a normal takeoff, but that the bomber pulled up steep into a vertical climb instead of leveling off. At about 500 feet the plane apparently was in a stall.

The bomber then fell off to the left, and nosed down and the pilot, using the throttle appeared to have recovered. This difficulty was experienced over the airport, but by the time the pilot apparently had regained control of the craft it was flying over the water an an altitude of about 100 feet, the bomber again fell off to the left and the wing struck the water.

A Consolidated spokesman said the crash had “evidence of sabotage.”

The spokesman said the $250,000, 25-ton land bomber had been “thoroughly tested, and things like that just don’t happen.”

Believed dead were:

William Wheatley, 39, Chester, N.Y., chief test pilot for the company.

Allen T. Austen, 28, Kansas City, Mo., assistant test pilot.

Bruce K. Craig, 27, Chicago, engineer.

William H. Rieser, 33, Cambridge, Mass.

Lewis M. McAannon, 25, Woodstock, Ill., chief mechanic, was seriously injured. ¹

The bodies of Wheatley, Craig and Austin had not been recovered from the shattered bomber.

The impact with the water shattered the bomber, witnesses said, and it sank. Navy and small fishing vessels went to the rescue. The plane went down in an area between the San Diego shoreline and the naval air station.

The bomber, called “Liberator” by the Royal Air Force, was of all-metal construction, and its type is regarded as one of the most advanced military weapons. The Liberator can travel 230 miles an hour with a full bomb load over a 3,000 mile range. Orders for the huge land bomber originally were placed by the French, then taken over by the British.

The first B-24 was delivered to the British last Feb. 15 when the craft Consolidated Aircraft officials said established a record non-stop transcontinental flight of 9 hours, 57 minutes for planes of more than 5,000 pounds gross weight.

—The Eugene Guard, Vol. 50, No. 152, Monday, June 2, 1941, at Page 1 Column 6 and Page 2, Column 2

This aerial photograph of Lindbergh Field, San Diego, California, shows the location of the PB4Y-2 crash site, and nearby, the position where the outer wing panel was found. (U.S. Navy)
This is a 1944 aerial photograph of Lindbergh Field, San Diego, California, part of an investigation of the crash of a brand-new Consolidated PB4Y-2 Privateer. The Pacific Ocean is at the upper left corner of the image. (U.S. Navy)

The Consolidated B-24 had first flown 29 December 1939. Chief Test Pilot Bill Wheatley was in command. Designed as a long-range heavy bomber for the U.S. Army Air Corps, it was a high-wing, four-engine monoplane with dual vertical fins and rudders. It had retractable tricycle landing gear. The bomber was flown by two pilots, with the crew including a navigator, bombardier, radio operator and several gunners.

The Royal Air Force Liberator B. Mk.I was essentially a B-24A. The Liberator Mk.II, though,  was lengthened by extending the nose in front of the cockpit by 3 feet (0.914 meters). It was equipped with two power-operated gun turrets, one at the top of the fuselage, just aft of the wing, and a second at the tail.

The Liberator Mk.II was 66 feet, 4 inches (20.218 meters) long with a wingspan of 110 feet, 0 inches (33.528 meters) and overall height of 18 feet, 0 inches (5.486 meters). It was heavier than the Mk.I as a result of the longer fuselage and the heavy power turrets. The maximum gross weight was 64,250 pounds (29,143 kilograms).

Consolidated LB30 Liberator II
Consolidated Model LB-30, Liberator B Mk.II

The LB-30/Mk.II was powered by four air-cooled, supercharged 1,829.4-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S3C4-G (R-1830-33) two-row fourteen-cylinder radial engines. These had a normal power rating of 1,100 horsepower at 2,550 r.p.m. to 6,100 feet (1,859 meters) and 1,000 horsepower at 2,700 r.p.m at 14,500 feet. The takeoff/military power rating was 1,200 horsepower at 2,700 r.p.m. to 5,000 feet (1,524 meters). The engines drove three-bladed Curtiss Electric variable-pitch propellers through a 2:1 gear reduction. The R-1830-33 was 4 feet, 0.06 inches (1.221 meters) in diameter and 5 feet, 3.48 inches (1.612 meters) long. It weighed 1,480 pounds (671 kilograms).

The Liberator Mk.II had a maximum speed of 263 miles per hour (423 kilometers per hour) at 15,000 feet (4,572 meters). Its service ceiling was 24,000 feet (7315 meters).

As was common with British bombers, the Liberator Mk.II was defended by Browning .303 Mk.II (7.7 × 56 mm) machine guns. Four were installed in the upper power turret and another four guns in the tail turret. Left and right waist positions each had two guns. One gun was mounted at the nose and one in the belly of the aircraft. This was a total of fourteen. The tail turret carried 2,200 rounds of ammunition and the top turret had 600 rounds.

Prime Minister Churchill's personal transport, "Commando," teh second Consolidated LB30 Liberator Mark II, AL504 © IWM (CH 14142)
Prime Minister Churchill’s personal transport, “Commando,” the second Consolidated LB30 Liberator Mark II, AL504. Its fuselage has been lengthened and tail surfaces from the PB4Y-2 Privateer installed. © IWM (CH 14142)

The second Liberator Mk.II, AL504, became the personal transport of Prime Minister Winston Churchill, who named it Commando. In 1944, the aircraft was modified to the single vertical fin configuration of the PB4Y-2 Privateer. Commando disappeared over the Atlantic in 1945.

William Ballentine Wheatley. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

William Ballantine Wheatley was born at Chester, New York, 17 December 1902, the first of three children of William A. Wheatley, a public school superintendent, and Mabel Ballantine Wheatley. He was twice married, first, about 1927, to Esther C. Wheatley, of Massachussetts. His second marriage was to Miss Grace Lenore Ray, 18 April 1935, at Washington, D.C. They would have a son and two daughters.

After two years of college, Wheatley joined the U.S. Army Air Corps as an aviation cadet, 3 March 1925. He trained as a pilot at Brooks Field, Texas, and was commissioned as a 2nd lieutenant, 13 March 1926. On 4 May 1927, Lieutenant Wheatley was assigned to the 118th Observation Squadron, 43rd Division, Air Service, at Hartford, Connecticut, as a pilot and observer. He served in the Air Corps Reserve until 1937.

In 1928, Wheatley went to work for the Pratt & Whitney Aircraft Company as a test pilot. He was an air mail pilot in 1928-1929, and then, in February 1929, he became a test pilot for Reuben H. Fleet’s Consolidated Aircraft Corporation at Buffalo, New York. In 1935, Consolidated moved to its new headquarters at Lindbergh Field, San Diego, California. Wheatley moved with it. He and his family lived in a 3 bedroom home about three miles northeast of the airport. In 1940, his salary as chief test pilot of Consolidated was $50,000 per year. ²

Following Wheatley’s death, Beryl Arthur Erickson was assigned as chief test pilot for Consolidated.

¹ Lewis McCannon also died as a result of the crash.

² Approximately $862,500 U.S. dollars in 2017.

© 2018 Bryan R. Swopes

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29 December 1939

The prototype Consolidated XB-24 heavy bomber takes off from Lindbergh Field.

29 December 1939: Consolidated Aircraft Corporation’s chief test pilot, William B. (“Bill”) Wheatley, made the first flight of the XB-24, 39-556, from San Diego Municipal Airport – Lindbergh Field, at San Diego, California. The flight crew included George Newman, co-pilot, and flight engineers Jack Kline and Bob Keith. The flight lasted just 17 minutes.

This airplane (the company designation was Model 32) was the prototype of the B-24 Liberator bomber. The U.S. Army Air Corps had approached Consolidated to set up a second production line for Boeing’s B-17 Flying Fortress four-engine heavy bomber. After looking at Boeing’s Seattle operation, Consolidated’s chief executive, Reuben H. Fleet, told the Air Corps that they could build a better, more modern bomber.

Consolidated XB-24 39-556.  (San Diego Air & Space Museum Archives)

The XB-24 was designed to be operated by a seven man crew. It was 63 feet, 9 inches (19.431 meters) long with a wingspan of 110 feet, 0 inches (33.528 meters), and was 18 feet, 8 inches (5.689 meters) high. The wings used the “Davis Airfoil” that had been used on the Model 31, a prototype flying boat, the XP4Y. The root chord was 14 feet, 0 inches (4.267 meters). Their angle of incidence was 3° 0′, with 3° 26° dihedral. The leading edges were swept aft 3° 30′.  The total wing area was 1,048 square feet (97.36 square meters).

The empty weight of the XB-24 was approximately 27,500 pounds ( kilograms), and its maximum takeoff weight was 46,400 pounds (21,047 kilograms).

Consolidated XB-24 39-556, 26 December 1939. (SDASM 44400746)

The XB-24 was powered by four air-cooled, supercharged 1,829.4-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S3C4-G (R-1830-33) two-row fourteen-cylinder radial engines. These had a normal power rating of 1,100 horsepower at 2,550 r.p.m. to 6,100 feet (1,859 meters) and 1,000 horsepower at 2,700 r.p.m at 14,500 feet. The takeoff/military power rating was 1,200 horsepower at 2,700 r.p.m. to 5,000 feet (1,524 meters). The engines drove three-bladed Curtiss Electric variable-pitch propellers through a 2:1 gear reduction. The R-1830-33 was 4 feet, 0.06 inches (1.221 meters) in diameter and 5 feet, 3.48 inches (1.612 meters) long. It weighed 1,480 pounds (671 kilograms).

Consolidated XB-24 low pass.

The XB-24  had cruise speed of 186 miles per hour (299 kilometers per hour), and a maximum speed of 273 miles per hour (439 kilometers per hour) at 15,000 feet (4,572 meters). The service ceiling was 31,500 feet (9,601 meters). Maximum range was 4,700 miles (4,828 kilometers), or 3,000 miles (7,564 kilometers) with 2,500 pounds (1,134 kilograms) of bombs.

The XB-24 was 38 miles per hour (61 kilometers per hour) slower than the Air Corps specification. A number of changes were made, including replacing the supercharged R-1830-33 engines with turbocharged Pratt & Whitney Twin Wasp TSC4-G (R-1830-41) engines. With the addition of the turbochargers, the R-1830-41s were able to maintain 1,200 horsepower up to 25,000 feet (7,620 meters). The propeller gear reduction ratio remained 2:1. At the same time, the round engine cowlings were changed to an elliptical shape that became a characteristic of the B-24. The modified prototype was redesignated XB-24B. In the new configuration, the bomber was able to reach 310 miles per hour (499 kilometers per hour), just 1 mile per hour under the Army’s requirement.

Consolidated XB-24 39-556 in flight near San Diego, California. (U.S. Air Force)

When the Royal Air Force bought several of the YB-24 pre-production airplanes, the Army Air Corps revised the serial numbers assigned to the B-24s. Though it was the same airplane, the XB-24′s designation was changed to XB-24B, and its serial number from 39-556 to 39-680.

The XB-24B was retained by Consolidated, now the Consolidated-Vultee Aircraft Corporation, and in 1944 further modified as a company transport. The prototype was scrapped at Brookley Field, Mobile, Alabama, 20 June 1946.

Consolidated-Vultee XB-24B 39-680 (formerly XB-24 39-556) after modification to a company transport. The large windows in the passenger areas could be covered by Venetian blinds. (U.S. Air Force)
Consolidated-Vultee XB-24B 39-680 (formerly XB-24 39-556) after modification to a company transport. The large windows in the passenger areas could be covered by Venetian blinds.

18,482 B-24 Liberators—more than any other Allied aircraft type—were built during World War II by Consolidated at San Diego, California and Fort Worth, Texas; by North American Aviation at Dallas, Texas; by Douglas Aircraft at Tulsa, Oklahoma. More than half of the total production was built by the Ford Motor Company at Willow Run. During World War II, the B-24 served in every combat theater. In U.S. Navy service, it was designated PB4Y-1 Privateer. It was faster, had a longer range, and could carry a heavier bomb load than the Boeing B-17, but was thought to be less survivable to combat damage. As the war came to an end, hundreds of brand new B-24s were accepted by the Air Corps, but sent immediately to be scrapped rather than placed in service.

William Ballentine Wheatley, (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

William Ballantine Wheatley was born at Chester, New York, 17 December 1902, the first of three children of William A. Wheatley, a public school superintendent, and Mabel Ballantine Wheatley. He was twice married, first, about 1927, to Esther C. Wheatley, of Massachussetts. His second marriage was to Miss Grace Lenore Ray, 18 April 1935, at Washington, D.C. They would have a son and two daughters.

After two years of college, Wheatley joined the U.S. Army Air Corps as an aviation cadet, 3 March 1925. He trained as a pilot at Brooks Field, Texas, and was commissioned as a 2nd lieutenant, 13 March 1926. On 4 May 1927, Lieutenant Wheatley was assigned to the 118th Observation Squadron, 43rd Division, Air Service, at Hartford, Connecticut, as a pilot and observer. He served in the Air Corps Reserve until 1937.

In 1928, Wheatley went to work for the Pratt & Whitney Aircraft Company as a test pilot. He was an air mail pilot in 1928-1929, and then, in February 1929, he became a test pilot for Reuben H. Fleet’s Consolidated Aircraft Corporation at Buffalo, New York. In 1935, Consolidated moved to its new headquarters at Lindbergh Field, San Diego, California. Wheatley moved with it. He and his family lived in a 3 bedroom home about three miles northeast of the airport. In 1940, his salary as chief test pilot of Consolidated was $50,000 per year.

Bill Wheatley was killed when a Royal Air Force Liberator B Mk.II, AL503, crashed into San Diego Bay during its acceptance flight, 2 June 1941. Four other Consolidated employees on board also died.

Consolidated Model LB-30, Liberator B Mk.II, AL503, photographed 2 June 1941—the same day it crashed. (Consolidated Aircraft Corporation)

© 2018, Bryan R. Swopes

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