26 March 1966

Aviation, , , , , , , , , , ,
Allison Engine Co. test pilot Jack l. Schweibold with teh record-setting prototype Hughes YOH-6A, 62-4213, at Edwards Air Force Base, California, 1966. (FAI)
Allison Engine Co. test pilot Jack Schweibold with the record-setting number three prototype Hughes YOH-6A Light Observation Helicopter, 62-4213, at Edwards Air Force Base, California, 1966. (FAI)

26 March 1966: Allison Engine Company test pilot Jack Schweibold flew the third prototype Hughes Aircraft Company YOH-6A Light Observation Helicopter, 62-4213, to set three Fédération Aéronautique Internationale (FAI) World Records for Distance Over a Closed Circuit Without Landing of 2,800.20 kilometers (1,739.96 miles), including an Absolute Record for Class E (Rotorcraft).¹ Two of these records still stand.

Hughes YOH-6A 62-4213 at Edwards Air Force Base, 1966. (FAI)
Hughes YOH-6A 62-4213 at Edwards Air Force Base, 1966. (FAI)

One week earlier, 20 March 1966, Hughes Aircraft Company test pilot Jack L. Zimmerman flew the same helicopter to set another distance record of of 1,700.12 kilometers (1,056.41 miles).² One 27 March, Zimmerman would set six more world records with 62-4213.³

Jack Schweibold wrote about the record flight in his autobiography, In the Safety of His Wings (Holy Fire Publishing, DeLand, Florida, 2005). He was one of a group of military and civilian test pilots selected to attempt a series of world record flights at Edwards Air Force Base, in the high desert of southern California. From 20 March to 7 April 1966, they flew 62-4213 over a series of distances and altitudes.

Edwards Air Force Base, California, circa 1970. The runway complex is at top, center. (U.S. Department of Defense)

Jack Schweibold’s record attempt began at midnight to take advantage of the cold desert air. The cold-soaked YOH-6A had been fueled with pre-cooled JP-5 in order to get the maximum amount of fuel on board. In addition to the standard fuel tank, two auxiliary tanks were placed in the cabin. The helicopter was so heavy from the overload that it could not hover. Jack made a running take-off, sliding the skids across the concrete until the increasing translational lift allowed the aircraft to break free of the ground. He began a very shallow climb.

Schweibold was flying a 60 kilometer (37.28 miles) closed course, but because of the near total darkness, he flew on instruments and was guided from the ground by Air Force test range radar controllers (Spatial Positioning and Orientation Radar Tracking, call sign SPORT). Accuracy was critical. The attempt would be disqualified if the helicopter cut inside of a pylon—which Jack could not see—but if he flew too far outside, the extra distance flown would not be counted and time would be lost. The maximum range would be controlled by the amount of fuel carried in the three tanks, and by the endurance of the pilot.

Throughout the flight, Jack gradually increased the altitude, as the T-63-A-5 turboshaft would be more efficient in thinner, colder air. He was flying a precisely calculated profile, taking into consideration aerodynamic drag, the efficiency of the helicopter’s rotor system, and the performance characteristics of the engine. He had been airborne for four hours before he climbed through 10,000 feet (3,048 meters).

Test pilot Jack Schweibold was featured in an advertising campaign by Allison.

At 14,000 feet (4,267 meters), Schweibold was on oxygen. He continued through 20,000 feet (6,096 meters) but was having trouble staying alert. (It would later be discovered that there was a malfunction in his oxygen mask.)

On the final lap, at 22,000 feet (6,706 meters) Jack had to fly around a towering cumulus cloud and radar contact was lost. He dived to lose altitude and popped out from under the cloud about a half-mile short of the runway.

When he shut down the engine, Jack Schweibold had flown the prototype YOH-6A 2800.20 kilometers (1,739.96 statute miles), non-stop. His record still stands.

Jack set 30 FAI World Records between 1966 and 1986. 26 of these remain current.

Frederick Jack Schweibold was born at Toledo, Ohio, 8 November 1935, the son of Henry E. and Jeanette Schweibold. He attended Ohio State University and majored engineering. He had enlisted in the United States Naval Reserve in 1952 and then joined the United States Air Force as an Aviation Cadet in 1954.

Jack Schweibold with a North American Aviation T-28A Trojan.

Schweibold went through pilot training at Randolph Air Force Base, San Antonio, Texas, flying the T-34 and T-28. He went on to train in the B-25 at Reese Air Force Base, Lubbock, Texas. He was commissioned as a second lieutenant and received his pilot’s wings in July 1957. In a momentary decision, he selected helicopter training.

Air Rescue Service Sikorsky H-19A Chicasaw 51-3850. (AR.1999.026)

Frederick Jack Schweibold married Miss Sharon Crouse at Toledo, Ohio, 27 December 1957.

Lieutenant Schweibold flew the Sikorsky H-19B for the U.S.A.F. Air Rescue Service, assigned to Oxnard Air Force Base, California. (The airfield is now Camarillo Airport, CMA, where I first soloed, and is about ten miles away from my desk.)

After leaving the Air Force, Jack flew Sikorsky S-55s for Chicago Helicopter Service, then Bell 47s for Butler Aviation. In 1960, he was hired by the Allison Division of General Motors as a test pilot and engineer for the new 250-series turboshaft engine.

A Chicago Helicopter Airways Sikorsky S-55.
Jack Schweibold

Jack Schweibold is the author of In The Safety Of His Wings: A Test Pilot’s Adventure, published in 2005.

I had the good fortune to have known Jack Schweibold. I first met him through his involvement in the Helicopter Association International’s biennial flight instructor re-certification seminars, held during the HAI’s annual conventions. He kept the seminar classes on track, and in between, was always available for questions. Jack was the authority on Allison’s 250-series turboshaft engines, and over the years I often called him for technical information and operational advice. On top of that, Jack Schweibold was just an all-around nice guy. It was a pleasure to know him.

U.S. Army Hughes YOH-6A prototype 62-4213 at Le Bourget, circa 1965.
U.S. Army Hughes YOH-6A prototype 62-4213 at Le Bourget, circa 1965. (R.A. Scholefield Collection)

The Hughes Model 369 was built in response to a U.S. Army requirement for a Light Observation Helicopter (“L.O.H.”). It was designated YOH-6A, and the first aircraft received U.S. Army serial number 62-4211. It competed with prototypes from Bell Helicopter Company (YOH-4) and Fairchild-Hiller (YOH-5). All three aircraft were powered by a lightweight Allison Engine Company turboshaft engine. The YOH-6A won the three-way competition and was ordered into production as the OH-6A Cayuse. It was nicknamed “loach,” an acronym for L.O.H.

The YOH-6A was a two-place light helicopter, flown by a single pilot. It had a four-bladed, articulated main rotor which turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) Stacks of thin stainless steel “straps” fastened the rotor blades to the mast and also allowed for flapping and feathering. Hydraulic dampers controlled lead-lag. Originally, there were blade cuffs around the main rotor blade roots in an attempt to reduce aerodynamic drag, but these were soon discarded. A two-bladed semi-rigid tail rotor was mounted on the left side of the tail boom. Seen from the left, the tail-rotor rotates counter-clockwise. (The advancing blade is on top.)

Overhead photograph of a Hughes YOH-6. Note the blade cuffs. (U.S. Army)
Overhead photograph of a Hughes YOH-6A. Note the blade cuffs. (U.S. Army)

The YOH-6A was powered by a T63-A-5 turboshaft engine (Allison Model 250-C10) mounted behind the cabin at a 45° angle. The engine was rated at 212 shaft horsepower at 52,142 r.p.m. (102% N1) and 693 °C. turbine outlet temperature for maximum continuous power, and 250 shaft horsepower at 738 °C., 5-minute limit, for takeoff. Production OH-6A helicopters used the slightly more powerful T63-A-5A (250-C10A) engine.

The Hughes Tool Company Aircraft Division built 1,420 OH-6A Cayuse helicopters for the U.S. Army. The helicopter remains in production as AH-6C and MH-6 military helicopters, and the MD500E and MD530F civil aircraft.

Hughes YOH-6A 62-4213 is in the collection of the United States Army Aviation Museum, Fort Rucker, Alabama.

The third prototype YOH-6A, 62-4213, testing the XM-7 twin M60 7.62 weapons system. (U.S. Army)
The third prototype YOH-6A, 62-4213, testing the XM-7 twin M60 7.62 weapons system. (U.S. Army)

¹ FAI Record File Numbers 786, 787 and 11656

² FAI Record File Number 762

³ FAI Record File Numbers 771, 772, 9920, 9921, 9922, and 9923

© 2019, Bryan R. Swopes

26 March 1955

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Pan American World Airways' Boeing 377-10-26 Stratocruiser serial number 15932, N1032V.
Pan American World Airways’ Boeing 377 Stratocruiser Clipper United States, N1032V.

26 March 1955: At 8:15 a.m. Saturday morning, Pan American World Airways Flight 845/26, a Boeing 377 Stratocruiser, Clipper United States, N1032V, departed Seattle-Tacoma Airport (SEA, or “SeaTac”) on a flight to Sydney, Australia, with intermediate stops at Portland, Oregon, and Honolulu, Hawaii. The airliner departed Portland (PDX) at 10:21 a.m., with a crew of 8 and 15 passengers on board.

Captain Herman S. Joslyn was in command of N1032V, with First Officer Angus Gustavus Hendrick, Jr.; Second Officer Michael F. Kerwick; Flight Engineer Donald Read Fowler; and Assistant Flight Engineer Stuart Bachman. The cabin crew were Purser Natalie R. Parker, Stewardess Elizabeth M. Thompson, and Steward James D. Peppin.

Clipper United States was cruising at 10,000 feet (3,048 meters) when a severe vibration began, lasting 5–8 seconds. The Number 3 engine (inboard, right) was violently torn off of the starboard wing. The damage to the airplane resulted in severe buffeting. The nose pitched down and airspeed increased. Captain Joslyn reduced engine power to limit airspeed. The Stratocruiser quickly lost 5,000 feet (1,524 meters). Because of damage to the engines’ electrical system, the flight engineer was not able to increase power on the remaining three engines. The Boeing 377 was too heavy at this early stage in the flight to maintain its altitude.

At 11:12 a.m. (19:12 UTC) the flight crew ditched the Stratocruiser into the north Pacific Ocean, approximately 35 miles (56 kilometers) west of the Oregon coastline. [N. 43° 48′ 15″, W. 125° 12′ 40″] The conditions were ideal for ditching,¹ but the impact was hard. Seats were torn loose, and several occupants were injured. Evacuation began and all three life rafts were inflated. The water temperature was 47 °F. (8.3  °C.).

A North American Aviation F-86F Sabre flown by Captain W. L. Parks, 142nd Fighter Interceptor Group, Oregon Air National Guard, located the scene of the ditching and observed smoke flares which led to two life rafts tied together. A Lockheed Constellation was also inbound to the scene from the south. After confirming that Air Force rescue aircraft were on the way, Captain Parks returned to Portland, very low on fuel.

Miss Natalie R. Parker (Medford Tribune)

The airliner’s purser, Miss Natalie R. Parker,² had been assisting passengers with their life vests and seat belts when the airliner hit the water. Standing in the aisle, she was thrown forward, knocking down five rows of seats as she hit them. She was badly bruised and suffering from shock.

Along with other crew members, Miss Parker assisted the passengers in abandoning the sinking Stratocruiser. After entering the water, some began to drift away. Miss Parker, despite her injuries, swam after one and towed him back to an inflated raft.

Her actions were particularly mentioned in the Civil Aeronautics Board accident investigation report:

The purser, a woman, although suffering from shock swam and towed the only seriously injured passenger to the nearest raft, some 200 feet [61 meters] distant.

—Civil Aeronautics Board Accident Investigation Report SA-304 File No. 1-0039, 15 November 1955, History of the Flight

The airliner floated for about 20 minutes before sinking. Of the 23 persons on board, four, passengers John Peterson, David Darrow, First Officer Hendrick, and Flight Engineer Fowler, died of injuries and exposure.

The survivors were rescued after two hours by the crew of USS Bayfield (APA-33), a U.S. Navy attack transport.

The U.S. Navy attack transport USS Bayfield (APA-33) during the rescue of the survivors of Pan Am Flight 845/26, 26 March 1955. A Standard Oil Co. tanker, SS Idaho Falls, stands by to assist. Two of the airliner’s life rafts are visible at the right edge of this photograph. One is at the end of the smoke trail crossing the center of the image. The other is a bright object at the right lower corner. (U.S. Coast Guard)

During the Civil Aeronautics Board hearings into the accident, Vice Chairman Joseph P. Adams commended the flight’s purser, Miss Parker:

“. . . all of us feel inspired that a fellow citizen, or just a fellow human being, can rise to such an occasion in the manner in which you did. It is most commendable, Miss Parker.“

—Civil Aeronautics Board Accident Investigation Report SA-304 File No. 1-0039, 15 November 1955, Footnote 3

Because the engine and propeller were not recovered, the exact nature of the failure could not be determined, but the most likely cause was considered to be a fracture of a propeller blade resulting in a severely unbalanced condition, followed by the violent separation of the engine from the wing. This was the fifth time that a Boeing 377 Stratocruiser had lost an engine following the failure of a hollow-steel Hamilton Standard 2J17 propeller blade.

When the flight engineer attempted to increase the propeller r.p.m. on the three engines simultaneously, an electrical overload occurred which opened the master circuit breaker. This prevented any engine power increase.

Airline stewardesses examine a cutaway model of the Boeing Stratocruiser. (Museum of History & Industry, Seattle)

Clipper United States was a Boeing Model 377-10-26, serial number 15932, registered N1032V. It was one of twenty of a specific variant built for Pan American World Airways. The airliner had been delivered to Pan Am on 21 May 1949. At the time of its loss, it had flown a total of 13,655 hours.

The Model 377 was a large, four-engine civil transport which had been developed concurrently with the Boeing B-50A Superfortress. The 377 followed the military C-97 Stratofreighter (Model 367), which used the wings, engines, landing gear and tail of the B-29. The B-50 and 377 shared the improved wings, engines and tail surfaces. The two airplanes made their first flights just 14 days apart. The Stratocruiser was operated by a flight crew of four. It was a double-deck aircraft, with the flight deck, passenger cabin and galley on the upper deck and a lounge and cargo compartments on the lower. The airliner was pressurized and could maintain Sea Level atmospheric pressure while flying at 15,500 feet (4,724 meters). The Model 377 could be configured to carry up to 100 passengers, or 28 in sleeping births.

A color photograph of a Pan American World Airways Boeing 377 Stratocruiser in flight. (Pan Am)
A Pan American World Airways Boeing 377 Stratocruiser in flight. (Boeing)

The Stratocruiser was 110 feet, 4 inches (33.630 meters) long with a wingspan of 141 feet, 3 inches (43.053 meters) and overall height of 38 feet, 3 inches (11.659 meters). The airliner had an empty weight of 83,500 pounds (37,875 kilograms) and the maximum takeoff weight was 148,000 pounds (67,132 kilograms).

N1032V was powered by four air-cooled, supercharged, 4,362.49-cubic-inch-displacement (71.488 liter) Pratt & Whitney Wasp Major B6 engines. These were four-row, 28-cylinder, radial engines with a compression ratio of 6.7:1.

The B6 had a Normal Power rating of 2,650 horsepower at 2,550 r.p.m., at 5,500 feet (1,676 meters), and Maximum Continuous Power rating of 2,800 horsepower at 2,550 r.p.m. at 3,500 feet (1,067 meters). The Takeoff Power rating was 3,500 horsepower at 2,700 r.p.m. with water/alcohol injection. ³

The engines drove four-bladed Hamilton Standard Hydromatic 24260 constant-speed propellers with a diameter of 17 feet (5.182 meters) through a 0.375:1 gear reduction.

The Wasp Major B6 was 4 feet, 7.00 inches (1.397 meters) in diameter and 8 feet, 0.50 inches (2.451 meters) long. It weighed 3,584 pounds (1,626 kilograms), dry. The propeller assembly weighed 761 pounds (345 kilograms).

The 377 had a cruise speed of 301 miles per hour (484 kilometers per hour) and a maximum speed of 375 miles per hour (604 kilometers per hour). During testing by Boeing, a 377 reached 409 miles per hour (658 kilometers per hour). Its service ceiling was 32,000 feet (9,754 meters) and the range was 4,200 miles (6,759 kilometers).

Boeing built 56 Model 377 Stratocruisers, with Pan American as the primary user, and another 888 military C-97 Stratofreighter and KC-97 Stratotankers.

Clipper America, a Pan American World Airways Boeing Model 377 Stratocruiser. (Boeing)

¹ Captain G.B. Cardew, master of the Matson Lines’ S.S. Hawaiian Educator, which had arrived on scene soon after the ditching, said, “The weather was perfect. The sea was calm and the sky warm and clear.”  —Oakland Tribune, Vol. CLXII, No. 86, Sunday, 27 March 1955, Page 2-A, Column 3

Natalie Parker, 1943. (Crater)

² Miss Natalie R. Parker was born 2 June 1925, the first child of Carold J. Parker, a potato chip manufacturer, and Ruth A. Parker, of Portland, Oregon. She attended Medford High School with the Class of 1943, where she was very active in extracurricular activities. Following graduation from high school, Miss Parker attended Reed College at Portland.

In 1945, Miss Parker enlisted in the United States Cadet Nurse Corps, U.S. Public Health Service, and trained as a nurse at the Johns Hopkins Hospital School of Nursing, Baltimore, Maryland. She graduated 13 June 1948.

Miss Parker joined Pan American World Airways in 1951.

Miss Natalie R. Parker married Rodney Collins Earnest, a building contractor, in Ellsworth, Maine, 21 October 1956. The wedding was officiated by Rev. S. George Bovill of the Congregational Church. They resided in Seattle, Washington. Mrs. Earnest became a founding partner and business manager of the Acorn Academy in Seattle.

³ During a demonstration of the Pratt & Whitney Wasp Major engine (military designation, R-4360) a regular production engine was taken from the assembly line and run for 22 continuous hours at 4,400 horsepower, then checked and run for another hour at 4,850 horsepower. It was then run for 100 hours at 3,000 horsepower, and 50 hours at 3,500 horsepower. When the engine was disassembled for inspection, it remained in serviceable condition.

© 2019, Bryan R. Swopes

26 March 1954

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This Convair RB-36H-40-CF Peacemaker Featherweight II, 51-13741, is similar to the B-36H involved in “The Miracle Landing” at Carswell AFB, 26 March 1954. (U.S. Air Force)

Insignia of 7th Bombardment Wing, Heavy 26 March 1954: While on a training mission, a Convair B-36H Peacemaker assigned to the 9th Bombardment Squadron, Heavy, 7th Bombardment Wing, Heavy, based at Carswell Air Force Base, Texas, and under the command of Captain Berry H. Young, suffers a series of failures that endangered the aircraft and its 19-man crew.

All three Pratt & Whitney Wasp Major reciprocating engines on the bomber’s right wing were inoperative. Insufficient electrical power was available to feather the propellers on two of those, increasing the drag on the right wing.

The four GE J47 turbojet engines, placed under the wings in 2-engine pods, could not be started.

With only three of the B-36’s ten engines operating, and all on the left wing, combined with the two unfeathered propellers on the right wing, the giant bomber yawed to the right.

Captain Young declared an emergency and returned to Carswell AFB, setting up a straight-in approach to the runway.

Carswell AFB, Fort Worth, Texas.

Problems with the hydraulic system prevented the airplane’s flaps from being lowered, and required that the landing gear be lowered by hand. Without flaps, the approach speed would have to be higher than normal to prevent the wings from stalling. With only three engines, there was insufficient power to “go around” for another attempt to land.

Following the emergency procedures, the crew was able to lower the landing gear just before the B-36 touched down.

In what has been described as “The Miracle Landing,” Captain Young made a “superior landing” and rolled until it came to a full stop.

The Fort Worth Star-Telegram reported:

Miracle Landing Saves Crewmen, Crippled B-36

     Nimble aircraft maneuvering saved 19 lives and a costly B-36 bomber here Friday.

     While hundreds of anxious airmen looked on, a B-36 landed at Carswell Air Force Base with a squadron of troubles aboard.

     Three engines were out.

     The landing flaps were out of commission.

     But Capt. Berry H. Young, aircraft commander and native Texan, landed the giant bomber safely on Carswell’s runway.

General on Hand

     First to pump Young’s hand was Brig. Gen. John D. Ryan, 19th Air Division commander, who rushed to the airplane as Young stepped to the ground.

     Here are the misfortunes that overtook the plane in sickening quickness just about 1 p.m. Friday:

     The No. 4 engine conked out. Captain Young feathered the prop.

     Seconds later, the No. 5 engine “ran away.” That means the propeller began to revolve at excessive speed.Young was forced to feather that prop, too.

     After a brief breather, the No. 6 engine started cutting out and quit.

     Young tried to start his outboard jets on his right wing. They refused to function.

     He declared an emergency condition and started to return to the base.

     As young neared the field he discovered he couldn’t lower the landing gear. The gear had to be lowered by emergency procedure, which included lowering the wheels by hand.

Superior Landing

     With all this facing him, Young executed what seasoned Carswell observers called a superior landing.

     Captain Young is a native of Dallas. His co-pilot was 1st Lt. Roland J. Reidy of Worcester, Mass. His flight engineer was 1st Lt. William E. Nunnery of San Diego, Cal., second flight engineer was 1st. Lt. John W. Williamson of Cedarville, Ohio.

     General Ryan said the entire crew of the ship behaved in sterling fashion and deserved full credit for saving the lives of those aboard the plane.

—Fort Worth Star-Telegram, Vol. 74, No. 55, Saturday, 27 March 1954, Page 1, Columns 3–5

Captain Young’s crew received the Strategic Air Command’s Crew of the Month Award, and the personal congratulations of General Curtiss E. LeMay.

This Convair RB-36D-5-CF Peacemaker, 49-2686, is similar in appearance to the B-36H involved in “The Miracle Landing,” 26 March 1954.

The Convair B-36H Peacemaker was the definitive version of the ten engine bomber, with 156 B-36H/RB-36H built out of the total production of 383 Peacemakers. It is similar to the previous B-36F variant, though with a second flight engineer’s position, a revised crew compartment, and improved radar controlling the two 20 mm autocannons in the tail turret.

The B-36H was 162 feet, 1 inch (49.403 meters) long with a wingspan of 230 feet (70.104 meters) and overall height of 46 feet, 8 inches (14.224 meters). The total area of its wings was 4,772 square feet (443.3 square meters). The wings’ leading edges were swept aft 15° 5′ 39″. Their angle of incidence was 3°, with -2° twist and 2° dihedral. The empty weight of the B-36H was 165,887pounds (75,245 kilograms) and the maximum takeoff weight is 357,500 pounds (162,159 kilograms).

The B-36H has ten engines. There are six air-cooled, supercharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The R-4360-53 had a Normal Power rating of 2,800 horsepower at 2,600 r.p.m. Its Military Power rating was 3,500 horsepower at 2,800 r.p.m., and 3,800 horsepower at 2,800 r.p.m. with water injection—the same for Takeoff. The engines turned three-bladed Curtiss Electric constant-speed, reversible propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

Four General Electric J47-GE-19 turbojet engines are suspended under the wings in two-engine pods. The J47 is a single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline and was rated at 5,200 pounds of thrust (23.131 kilonewtons).

The B-36H was the fastest variant of the Peacemaker series, with a cruise speed of 216 knots (249 miles per hour/400 kilometers per hour) and a maximum speed of 382 knots (440 miles per hour/707 kilometers per hour) at 35,500 feet (10,820 meters). The service ceiling was 47,000 feet (14,326 meters) and its combat radius was 3,190 nautical miles (3,671 statute miles/5,908 kilometers). The ferry range was 7,120 nautical miles (8,194 statute miles/13,186 kilometers).

The B-36H has six remotely-controlled retractable gun turrets mounting two M24A1 20 mm autocannon, each, with 600 rounds of ammunition per gun. The tail turret was radar-controlled, and another 2 guns were mounted in the nose.

The B-36 was designed during World War II, when nuclear weapons were unknown to the manufacturer. The bomber was built to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs in fours bomb bays. It could carry two 43,000 pound ( kilogram) T-12 Cloudmakers, a conventional explosive earth-penetrating bomb, or several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 25-megaton thermonuclear bomb could be carried.

© 2023, Bryan R. Swopes

26 March 1940

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Curtiss-Wright CW-20T, NX19436, s/n 101. (Unattributed)

26 March 1940: At Lambert–St. Louis Municipal Airport, just to the west of the Mississippi River in the state of Missouri, test pilots Edmund Turney (“Eddie”) Allen and Dean Cullen Smith took the prototype Curtiss-Wright CW-20T, NX19436, for its first flight.

BIMOTORED GIANT READY FOR TESTS

Curtiss-Wright Substratosphere Plane Works Smoothly in Takeoff

By DEVON FRANCIS

Associated Press Aviation Editor.

     ST. LOUIS, March 27.—The world’s first bi-motored transport plane designed and powered to eliminate the hazard attending the failure of one engine on takeoff was made ready for two months or more of flight-testing today before being offered to commercial airlines.

     The 19-ton, 36-passenger Curtiss-Wright substratosphere transport was engineered to permit one engine to go dead at any point on the take-off as a pilot climbs for altitude and still maintain safe flight.

     Each of its engines produces 1700 horsepower. The largest engines ever to be fitted to a transport plane heretofore have been of 1500 horsepower. Either one of the new transport’s engines will carry it to an altitude of 13,000 feet.

     Fastened to the 108-foot wing with rubber cushions to produce what Curtiss-Wright engineers described as “dynamic balance,” the engines transmit only about 50 per cent of the normal vibration to the cabin of the plane.

     C, s/n 101. W. France, vice president and general manager of the St. Louis airplane division of the company, yesterday witnessed the maiden take-off of the transport from the ground. Then he climbed to the control tower of the St. Louis municipal airport for an innovation in airplane testing.

     France called the test pilot, Eddie Allen of Seattle, on the tower radiophone.

     Dean Smith, co-pilot, answered.

     “Dean,” he said, “that looked grand. Congratulations.”

     “O. K.,” replied Smith, “I’ll tell Eddie.”

     A little later Allen brought the huge plane into a smooth landing. He remarked that the plane had flown 190 miles an hour on only 30 per cent of its power. Transports usually cruise at 50 to 55 per cent.

     The additional testing will be for an approved type certificate from the government.

—Buffalo Evening News, Vol. CXIX, No. 142, Wednesday, 27 March 1940, Page 18, Column 3

Curtiss-Wright CW-20T NX19436, s/n 101. (Unattributed)

The Curtiss-Wright CW-20T, NX19436, (manufacturer’s serial number 101) was a prototype twin-engine commercial airliner designed by George Augustus Page, Jr. Originally built with a twin-tail configuration, flight testing resulted in a change to a single, large vertical fin and rudder. Designed to be pressurized, the fuselage had a Figure 8 cross section, with the cabin floor at the narrowest point for increased strength. In this prototype, the fuselage was faired over to provide a smooth, more cylindrical shape. Considerable wind tunnel testing had been performed by CalTech in Pasadena, California, resulting in a very sleek nose section.

Curtiss-Wright CW-20T NX19436. (Unattributed)

On 20 June 1941, the United States Army Air Forces ¹ purchased the CW-20T and designated it as the Curtiss C-55, serial number 41-21041. It would become the prototype of the C-46 Commando military transport. The Army Air Forces returned the C-55 to Curtiss-Wright for modifications.

Curtiss-Wright CW-20T NX19436, after modification to a single tail configuration, photographed at Midway Airport, Chicago, 19 May 1941. (Midway Airport)

The CW-20T was 76 feet, 4 inches (23.266 meters) long with a wingspan of 108 feet, 0 inches (32.918 meters). It was powered by two air-cooled, supercharged, 2,603.7-cubic-inch-displacement (42.688 liters) Wright Aeronautical Corporation Cyclone 14 GR2600A5B-5 (R-2600-17A) two-row, 14-cylinder radial  engines, driving three-bladed Curtiss Electric C-533-D controllable-pitch propellers through a 16:9 gear reduction. This engine had a compression ration of 6.9:1 and required 100/130 aviation gasoline. It was rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,500 r.p.m. It was 5 feet, 3.1 inches (1.603 meters) long, 4 feet, 6.26 inches (1.378 meters) in diameter and weighed 1,980 pounds (898 kilograms). Only four of these engines were built.

Curtiss-Wright CW-20T NX19346, at right, with a CW-21B prototype, NX19441. (Unattributed)

NX14936 was sold to the British Overseas Airways Corporation (BOAC) in September 1941 and registered in the United Kingdom as G-AGDI. The airline named it St. Louis. It was converted to a 24-passenger configuration with long-range fuel tanks. It frequently flew between Lisbon, Gibraltar and Malta. The airplane was scrapped 29 October 1943.

British Overseas Airways Corporation Curtiss-Wright CW-20T, G-AGDI, “St. Louis,” at Gibraltar, circa 1942. (Imperial War Museum)

After the necessary redesign, which included a large cargo door and strengthened floor, and the substitution of 2,000 horsepower Pratt & Whitney R-2800-51 engines for the Wright Cyclone 14s of the C-55, the Army Air Forces ordered the airplane into production as the C-46A-CU Commando. An order was placed for 200 aircraft. The U.S. Navy placed 160 in service as the R5C-1. Curtiss-Wright built the C-46 at St. Louis and Buffalo, New York. The first, 41-5159, was delivered 13 July 1942. More than 3,000 C-46s were built in nearly 30 variants. Two C-46A-1-HI Commandos were built by Higgins Aircraft at Michoud, Louisiana.

Like the CW-20T, the C-46A/R5C-1 was also 76 feet, 4 inches (23.266 meters) long with a wingspan of 108 feet, 0 inches (32.918 meters) and overall height of 21 feet, 8 inches (6.604 meters). The wing area was 1,360 square feet (126.35 square meters). It had an empty weight of 30,241 pounds (13,717 kilograms) and maximum take off weight of 52,000 pounds (23,586 kilograms). The maximum payload was 10,000 pounds (4,536 kilograms). The maximum package size was 7 feet, 6 inches × 5 feet × 6 feet, 8 inches (2.286 × 1.524 × 2.032 meters).

The C-46A was powered by two air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liter), Pratt & Whitney R-2800-51 two-row, 18-cylinder radial engines with a compression ratio of 6.65:1. They drove three-bladed propellers through a 2:1 gear reduction. These engines had a Normal Power rating of 1,600 horsepower at 2,400 r.p.m. at 5,700 feet (1,737 meters), or 1,400 horsepower at 13,000 feet (3,962 meters). The Military Power rating was 2,000 horsepower at 2,700 r.p.m. at 1,500 feet (457 meters), or 1,600 horsepower at 13,500 feet (4,115 meters). Takeoff power was 2,000 horsepower at 2,700 r.p.m. The R-2600-51 was 6 feet, 3.72 inches (1.923  meters) long, 4 feet, 4.50 inches (1.335 meters) in diameter, and weighed 2,300 pounds (1,043 kilograms). All R-2600-51s were built by the Ford Motor Company.

The C-46A had a maximum speed of 233 knots (268 miles per hour/432 kilometers per hour) at 16,100 feet (4,907 meters). Its service ceiling was 20,600 feet (6,279 meters). With a fuel capacity of 3,000 gallons (11,356 liters), the maximum range was 1,960 nautical miles (2,256 statute miles/3,630 kilometers) at 121 knots (139 miles per hour/224 kilometers per hour).

During World War II, the C-46 famously flew “The Hump,” from bases in Burma, over the Himalaya Mountains, and into China.

The first Curtiss-Wright C-46A-CU Commando, 41-5159, circa 1942. (U.S. Air Force)

¹ The United States Army Air Corps (USAAC) became the United Army Air Forces (USAAF) on 20 June 1941.

© 2023, Bryan R. Swopes

26 March 1938

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A. E. Clouston on the wing of Australian Anniversary, Croydon, 26 March 1938.

26 March 1938: On Saturday afternoon at 5:40 p.m., RAE Farnborough test pilot Flying Officer Arthur Edmond Clouston ¹ and his co-pilot, newspaper correspondent Victor Anthony Ricketts,² landed at Croydon, London. England, completing an 11-day, 26,450-mile (42,567 kilometers) round trip flight from England to New Zealand and return. Their airplane, a twin-engined de Havilland DH.88 Comet, G-ACSS, named Australian Anniversary in honor of the 150th anniversary of the founding of Australia, finished the course in 10 days, 21 hours, 22 minutes. During the flight, four Fédération Aéronautique Internationale (FAI) World Records for Speed Over a Recognised Course were set.³

The Comet was one of three built especially for the 1934 MacRobertson Trophy Air Race, England to Australia, which it had won with an elapsed time of 70 hours, 54 minutes.

De Havilland DH-88 Comet G-ACSS, Australian Anniversary, Blenheim, New Zealand, 20 March 1938 (National Library of New Zealand)

Clouston and Ricketts departed Gravesend, Kent, England, at 8:17 p.m., Tuesday, 15 March 1938. They arrived at Blenheim, on New Zealand’s South Island, at 04:57 G.M.T., Sunday, 20 March. They began the return trip at 10:20 G.M.T., 21 March.

After listing the stops during the flights, with times and distances for each leg, FLIGHT commented:

     Set down thus in bare figures, that it may be kept on record, the story of the flight sounds, perhaps, prosaic. But against this background may be pictured the actual sensations of the two men who made it; the ten-hour 2,000-miles stretches, sometimes protracted to 12 hours by head winds; the incessant roar, scream and bumping in the cramped tandem cockpit, the desire for sleep; the anxieties of taking-off from small aerodromes in “thin” tropical air with nearly a ton of petrol; fog, cloud and thunderstorms, all of which were encountered. These things considered, one may marvel at the enthusiasm of people who will do them—and it so happens that quite “uncommercial” enthusiasm has played a large share in the present flight.

—FLIGHT, The Aircraft Engineer & Airships, No. 1527, Vol. XXXIII, 31 March 1938, Page 318, Column 2

The de Havilland DH.88 Comet was a two-place, twin engine monoplane with retractable landing gear. It was built of wood, with a framework covered with spruce plywood for the skin of the fuselage, and a layer of doped fabric covering the wings.

The airplane was 29 feet, 0 inches (8.839 meters) long with a wingspan of 44 feet, 0 inches (13.411 meters) and overall height of 10 feet, 0 inches (3.048 meters). It had an empty weight of 2,930 pounds (1,329 kilograms) and loaded weight of 5,500 pounds (2,495 kilograms).

De Havilland DH.88 Comet three-view illustration with dimensions. (Flight, 20 September 1934, Page 969)

The Comet was originally powered by two air-cooled, normally-aspirated, 9.186 liter (560.573-cubic-inch-displacement) de Havilland Gipsy Six R engines. The Gipsy Six was an inverted, inline six-cylinder, direct-drive engine. The R version had the compression ratio increased from 5.25:1 to 6.5:1, and produced 223 horsepower at 2,400 r.p.m. for takeoff. The engines turned two-bladed, variable pitch propellers.

The Gipsy Six R engine was designed by Major Frank Bernard Halford C.B.E. F.R.Ae.S., who had designed the four-cylinder de Havilland Gipsy engines and would later design the Goblin and Ghost turbojet engines. Halford was awarded the Silver Medal by the Royal Aeronautical Society for his work on the DH.88 Comet in the MacRobertson race.

The DH.88 had maximum speed of 255 miles per hour (410 kilometers per hour). Its range was 2,925 miles (4,707 kilometers). The service ceiling was 19,000 feet (5,791 meters).

Two additional DH.88 Comets were built. Of the five, one crashed in the Sudan in 1935. The crew safely bailed out. Two more were destroyed in a hangar fire at Istres, France, in June 1940. G-ACSP, Black Magic, which had been flown by Jim and Amy Mollison in the MacRobertson Trophy Race, was located in Portugal and is under restoration at Derby Airfield, England.

De Havilland DH.88 Comet c/s 1966 was purchased by Arthur Octavius Edwards (better known, simply, as A.O. Edwards), and registered G-ACSS, 4 September 1934. Edwards named the airplane Grosvenor House, after a luxury hotel in Park Lane which he had developed from “the biggest and most spectacular” mansion in London.

De Havilland DH.88 Comet K5084 (c/n 1996) in Royal Air Force markings. © IWM (MH 5416)

In June 1935, G-ACSS was “taken charge” by the Air Ministry for flight testing. It was re-painted silver and assigned the RAF identification K5084. While undergoing flight testing, the Comet was damaged during a landing at the Aircraft & Armaments Engineering Establishment (A&AEE) at RAF Martlesham Heath and sold as scrap. It was purchased by Frederick E. Tasker, an architect famous for his Art Deco buildings, and rebuilt by Essex Aero Ltd., Gravesend. Essex replaced the Gipsy Six R engines with Gipsy Six Series II angines.

By June 1937 the racer was once again airworthy. It carried the identification mark “E.1” on the fuselage before reverting to G-ACSS. Flown by A.E. Clouston, it competed in the Istres–Damascus–Paris air race of August 1937, placing fourth.

In October–November 1937, Clouston flew G-ACSS from London to Cape Town and return, establishing records in both directions. ⁴ The Comet was again re-painted, this time beige, and re-named The Burberry after its new sponsor, Burberry Ltd., makers of the classic gabardine “trench coat.”

The Comet was placed in storage and scavenged for parts during World War II. De Havilland employees restored G-ACSS in 1951. It was donated to The Shuttleworth Collection in 1965.

G-ACSS has been restored to flying condition and is in the Shuttleworth Collection at Old Warden Aerodrome, Bedfordshire, England.

De Havilland DH.88 Comet G-ACSS, photographed 7 September 2014. (Woldere via Wikipedia)

De Havilland’s experience with the Comet led directly to their success with its big brother, the famous World War II fighter bomber, the DH.98 Mosquito.

Group Captain A. E. Clouston, D.S.O., D.F.C., A.F.C., Royal Air Force. (Art UK)

¹ Air Commodore A.E. Clouston, C.B., D.S.O., D.F.C., A.F.C., Royal Air Force (29162)

Pilot Officer Victor Anthony Ricketts, DFC, Royal Air Force.

² Flight Lieutenant Victor Anthony Ricketts, D.F.C., Royal Air Force Volunteer Reserve (77341), flying a DH.98 Mosquito B Mk IV with No. 248 Squadron, was killed in action 12 July 1942.

³ FAI Record File Numbers: 13253, 19 March 1938, 209,71 km/h (130.31 m.p.h.); 13254, 20 March 1938, 180,26 km/h (111.85 m.p.h.); 13255, 26 March 1938, 134,31 km/h (83.46 m.p.h.);, and 13256, 26 March 1938, 130,78 km/h (81.26 m.p.h.).

⁴ FAI Record File Numbers: 13242, 16 October 1937, 214,08 km/h (133.02 m.p.h.); 13259, 20 November 1937, 168.26 km/h (105.55 m.p.h.)

© 2019, Bryan R. Swopes