Tag Archives: Prototype

10 November 1949

Sikorsky YH-19 49-2012 first flight, Bloomfield, Connecticut, 10 November 1949. (Sikorsky, a Lockheed Martin Company)

10 November 1949: At Bloomfield, Connecticut, Dimitry D. (“Jimmy”) Viner, a nephew of Igor Sikorsky and chief test pilot for the Sikorsky Aircraft Corporation, made the first flight of the prototype Sikorsky S-55 helicopter, serial number 55-001, which the U.S. Air Force had designated YH-19 and assigned serial number 49-2012.

Five YH-19 service test aircraft were built. Two were sent to Korea for evaluation in combat. As a result, the United States Air Force placed an initial order for 50 H-19A Chickasaw helicopters. (It is customary for U.S. Air Force and U.S. Army helicopters to be named after Native American individuals or tribes, though there are exceptions.) This was quickly followed by orders for 264 H-19B helicopters.

Sikorsky YH-19 49-2014 in Korea, circa 1951. (U.S. Air Force)

The United States Navy ordered 118 S-55s which were designated HO4S-1 and HO4S-3. The U.S. Coast Guard bought 30 HO4S-1G and HO4S-3Gs configured for rescue operations. The U.S. Marine Corps purchased 244 HRS-1, HRS-2 and HRS-3 helicopters. The U.S. Army ordered 353 H-19C and H-19D Chickasaw utility transports. The remaining 216 Sikorsky-built helicopters were S-55, S-55C and S-55D commercial models.

Cutaway drawing of the Sikorsky S-55/H-19/HO4S/HRS. Note the rearward-facing, angled placement of the radial engine.(Sikorsky Historical Archives)
Cutaway illustration of the Sikorsky S-55/H-19/HO4S/HRS. Note the rearward-facing, angled placement of the radial engine. (Sikorsky Historical Archives)

The S-55 was flown by two pilots in a cockpit placed above the passenger/cargo compartment. The most significant design feature was moving the engine from directly under the main rotor mast to a position at the front of the helicopter. Installed at an angle, the engine turned a drive shaft to the main transmission. The engine placement provided space for a large passenger/cargo compartment. The aircraft was constructed primarily of aluminum and magnesium, with all-metal main and tail rotor blades.

The main rotor consisted of three fully-articulated blades built of hollow aluminum spars, with aluminum ribs. Spaces within the blade were filled with an aluminum honeycomb. The blades were covered with aluminum sheet. The hollow spars were filled with nitrogen pressurized to 10 p.s.i.  An indicator at the blade root would change color if nitrogen was released, giving pilots and mechanics an indication that the spar had developed a crack or was otherwise compromised. The main rotor turned counter-clockwise as seen from above. (The advancing blade is on the helicopter’s right.) Flapping hinges were offset from the main rotor axis, giving greater control response and effectiveness. The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 42 feet, 2 inches (12.852 meters). The main rotor had a diameter of 53 feet, 0 inches (16.154 meters) and tail rotor diameter was 8 feet, 8 inches (2.642 meters), giving the helicopter an overall length with all blades turning of 62 feet, 2 inches (18.948 meters). It was 13 feet, 4 inches (4.064 meters) high. The landing gear tread was 11 feet (3.353 meters). The S-55 had an empty weight of 4,785 pounds (2,173 kilograms) and maximum takeoff weight of 7,200 pounds (3,271 kilograms). Fuel capacity was 185 gallons (698 liters).

The YH-19 was powered by an air-cooled, supercharged 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney R-1340-57 (Wasp S1H2) 9-cylinder radial engine mounted at a 35° angle in the fuselage forward of the crew compartment. This was a direct-drive engine which had a Normal Power rating of 550 horsepower at 2,200 r.p.m. to 8,000 feet (2,438 meters), and 600 horsepower at 2,250 r.p.m. for Take Off.

Later production S-55 commercial and H-19/HO4S and HRS military helicopters used an air-cooled, supercharged 1,301.868-cubic-inch (21.334 liter) Wright Aeronautical Division 871C7BA1 Cyclone 7 (R-1300-3) 7-cylinder radial engine with a compression ratio of 6.2:1. The R-1300-3 was also a direct-drive engine, but was rated at 700 horsepower at 2,400 r.p.m., Normal Power, and 800 horsepower at 2,600 r.p.m. for Take-Off. Both engines incorporated a large cooling fan to circulate air around the cylinders. The R-1300-3 was 49.68 inches (1.261 meters) long, 50.45 inches (1.281 meters) in diameter, and weighed 1,080 pounds (490 kilograms).

Sikorsky Aircraft Corps. YH-19 49-2012 (c/n 55-001) shown with engine "clam shell" doors open. This allowed excellent access to the engine for maintenance.
Sikorsky Aircraft Corps. YH-19 49-2012 (c/n 55-001) shown with engine “clam shell” doors open. This allowed excellent access to the engine for maintenance. (Sikorsky Historical Archives)

The S-55 had a maximum speed of 95 knots (109 miles per hour, 176 kilometers per hour) at Sea Level. The helicopter’s hover ceiling in ground effect (HIGE) was 7,875 feet (2,400 meters) and out of ground effect (HOGE) is 4,430 feet (1,350 meters). The service ceiling was 11,400 feet (3,475 meters) and range was 405 miles (652 kilometers).

Sikorsky Aircraft Corporation built 1,281 S-55-series helicopters. Another 477 were built under license by Westland Aircraft Ltd., Société Nationale des Constructions Aéronautiques du Sud-Est (SNCASE) and Mitsubishi Heavy Industries.

49-1012 is in the collection of the Smithsonian Institution National Air and Space Museum.

The first of five YH-19 service test helicopters, 49-2012 is on display at the Smithsonian Institution National Air and Space Museum. (NASM)
The first of five YH-19 service test helicopters, 49-2012, is on display at the Smithsonian Institution National Air and Space Museum. (NASM)
Dimitry D. Viner, circa 1931

Дмитро Дмитрович Вінер (Dimitry Dimitry Viner) was born in Kiev, Ukraine, Imperial Russia, 2 October 1908. He was the son of Dimitry Nicholas Weiner and Helen Ivan Sikorsky Weiner, a teacher, and the sister of Igor Ivanovich Sikorsky.

At the age of 15 years, Viner, along with his mother and younger sister, Galina, sailed from Libau, Latvia, aboard the Baltic-American Line passenger steamer S.S. Latvia, arriving at New York City, 23 February 1923.

“Jimmy” Viner quickly went to work for the Sikorsky Aero Engineering Company, founded by his uncle, Igor Sikorsky.

Dimitry Viner became a naturalized United States citizen  on 27 March 1931.

Viner married Miss Irene Regina Burnett. The had a son, Nicholas A. Viner.

A Sikorsky YR-5A flown by Jimmy Viner with Captain Jack Beighle, hoists a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)

On 29 November 1945, Jimmy Viner and Captain Jackson E. Beighle, U.S. Army, flew a Sikorsky YR-5A to rescue two seamen from an oil barge which was breaking up in a storm off of Fairfield, Connecticut. This was the first time that a hoist had been used in an actual rescue at sea.

Jimmy Viner made the first flight of the Sikorsky S-51 prototype on 16 February 1946, and in 1947, he became the first pilot to log more than 1,000 flight hours in helicopters.

Dimitry Dimitry Viner died at Stratford, Connecticut, 14 June 1998, at the age of 89 years.

Dimitry D. (“Jimmy”) Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)

© 2018, Bryan R. Swopes

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9 November 1944

Boeing XC-97 43-27470, the first of three Model 367 prototypes. (Boeing)
Boeing XC-97 43-27470, the first of three Model 367 prototypes. (San Diego Air and Space Museum Archive)

9 November 1944: Boeing’s senior test pilot, Albert Elliott Merrill, and co-pilot John Bernard Fornasero make the first flight of the Boeing Model 367 prototype, XC-97 43-27470.

The airplane was a prototype for a very long range military transport.  It used the wings, engines and tail of the B-29 Superfortress heavy bomber.

Boeing XC-97 three-view illustration with dimensions. (Warbird Information Exchange)

The three  XC-97 prototypes were 110 feet, 4 inches (33.630 meters) long with a wingspan of 141 feet, 2.76 inches (43.0469 meters) and overall height of 33 feet, 2.8 inches (10.130 meters).

The production C-97A first flew in 1949.  It used the more powerfull engines and taller vertical fin of the B-50 Superfortress. The transport had a flight crew of five and could carry 134 troops or 83 litters. The Stratofreighter’s  empty weight was 76,143 pounds (34,538 kilograms) and maximum takeoff weight of 175,000 pounds (79,379 kilograms). The maximum cargo capacity was 67,080 pounds (30,427 kilograms).

The KC-97A had a maximum speed of 334 knots (384 miles per hour, or 619 kilometers per hour) at 26,000 feet (7,925 meters). Its ceiling was 34,500 feet (10,516 meters) and the airplane’s combat range was 1,661 nautical miles (1,911 statute miles/3,076 kilometers).

Boeing built 888 C-97 Stratofreighters and KC-97 Stratotankers between 1947 and 1958. The type was finally retired from the U.S. Air Force in 1978. Another 56 Model 377 Stratocruiser civil transports were produced.

Boeinng XC-97 43-27470. (David Horn Collection, 1000aircraftphotos)

© 2019, Bryan R. Swopes

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6 November 1935

Test pilot George Bulman in the cockpit of the prototype Hawker Monoplane F.36/34, K5083.

6 November 1935: The prototype Hawker Monoplane F.36/34, K5083, first flew at the Brooklands Aerodrome, Weybridge, Surrey, with Hawker’s Chief Test Pilot, Flight Lieutenant Paul Ward Spencer (“George”) Bulman, M.C., A.F.C., Royal Air Force Reserve,¹ in the cockpit. The airplane would be named “Hurricane” and become one of the most successful fighter aircraft of World War II.

Designed by Sydney Camm to meet a Royal Air Force Specification for a high speed monoplane interceptor, the airplane was developed around the Rolls-Royce PV-12 engine.

Sir Sydney Camm, CBE, FRAeS
Sir Sydney Camm, C.B.E., F.R.Ae.S. (1893–1966)

The Hurricane was built in the traditional means of a light but strong framework covered by doped linen fabric. Rather than wood, however, the Hurricane’s framework used high strength steel tubing for the aft fuselage. A girder structure covered in sheet metal made up the forward fuselage. A primary consideration of the fighter’s designer was to provide good visibility for the pilot. The cockpit sits high in the fuselage and gives the airplane its characteristic hump back profile. The cockpit was enclosed by a sliding canopy. The landing gear was retractable.

Hawker Monoplane F.36/34, K5083, front view. (World War Photos)
Hawker Monoplane F.36/34, K5083, the prototype Hawker Hurricane, photographed prior to its first flight. Note the flush exhaust ports and wooden fixed-pitch propeller. Photograph © IWM (MH 5475)
Right Profile of the prototype Hawker Hurricane, K5083. (© IWM-MH-5190)
Right profile of the prototype Hawker Monoplane F.36/34, K5083. © IWM (MH-5190)
Left profile (IWM)
Hawker Monoplane F.36/34, K5083. Left profile. © IWM (ATP 8654D)
Hawker Monoplane F.36/34, K5083, left rear quarter view. (World War Photos)

The Rolls-Royce PV-12 (“PV” stood for Private Venture) was a developmental liquid-cooled 1,649-cubic-inch-displacement (27.022 liter) 60° V-12 that would become the legendary Merlin aircraft engine. The PV-12 first ran in 1933 and initially produced 700 horsepower.

The engine was progressively improved and by the time the Hurricane prototype first flew, it was equipped with a supercharged Rolls-Royce Merlin C, Air Ministry serial number 111144. The Merlin C had a Normal Power rating of 1,029 horsepower at 2,600 r.p.m, at an altitude of 11,000 feet (3,353 meters), with +6 pounds per square inch boost. The V-12 engine turned a Watts two-bladed fixed-pitch wooden propeller through a gear reduction drive (possibly 0.420:1).

Right profile of the prototype Hawker Hurricane, K5083. Photograph © IWM (MH 5190)
Right quarter view of the prototype Hawker Monoplane F.36/34, K5083, in flight. Photograph © IWM (MH 5190)

An Aeroplane and Armament Experimental Establishment (A&AEE) test pilot, Flight Sergeant Samuel (“Sammy”) Wroath (366485), flew K5083 at the Martlesham Heath in early 1936. He wrote, “The aircraft is simple to fly and has no apparent vices.”

In early flight testing, K5083 had a maximum speed of 253 miles per hour (407 kilometers per hour) at Sea Level, an reached 315 miles per hour (507 kilometers per hour) at 16,200 feet (4,938 meters), with the Merlin turning 2,960 r.p.m., with +5.7 pounds of boost (0.39 Bar). The speed exceeded the RAF’s requirement by 5 miles per hour (8 kilometers per hour).

The prototype was able to take off in as little as 795 feet (242 meters) and to climb to 15,000 feet (4,572 meters) in just 5 minutes, 42 seconds. It reached 20,000 feet (6,096 meters) in 8 minutes, 24 seconds. The peak altitude reached was 30,000 feet (9,144 meters). The prototype’s estimated service ceiling was 34,500 feet (10,516 meters)and the estimated absolute ceiling was 35,400 feet (10,790 meters).

In May 1939 Hawker Monoplane F.36/34 K5083 was classified as a ground instruction airframe, with serial number 1112M. Reportedly, it remained in airworthy condition until 1942. Its status after that is not known.

Hawker Monoplane F.36/34 K5083 with “alighting gear” extended. (World War Photos)

The Hawker Hurricane Mk.I was ordered into production in the summer of 1936. The first production airplane, L1547, flew on 12 October 1937. The Hurricane Mk. I retained the wooden fixed-pitch propeller and fabric-covered wings of the prototype, though this would change with subsequent models.

The first production Hawker Hurricane Mk.I, L1547, circa October 1937. This airplane, assigned to No. 312 Squadron, was lost 10 October 1940, when it caught fire during a training flight near RAF Speke. The pilot, Sergeant Otto Hanzliĉek, parachuted from the airplane, but he landed in the Mersey River and drowned.

The Hurricane Mk.I was 31 feet, 5 inches (9.576 meters) long with a wingspan of 40 feet, 0 inches (12.192 meters), and overall height of 13 feet, 3 inches (4.039 meters) in three-point attitude. The wings had a total area of 257.6 square feet (23.9 square meters). Their angle of incidence was 2° 0′, and the outer wing panels had 3° 30′ dihedral. The leading edges were swept aft 5° 6′. The empty weight of the Hurricane I was 5,234 pounds (2,374 kilograms) and maximum gross weight was 6,793 pounds (3,081 kilograms).

The Hurricane Mk.I was powered by a Rolls-Royce Merlin Mk.II or Mk.III. The Mk.III was rated at 1,030 horsepower at 3,000 r.p.m. at 16,250 feet (4,953 meters). The engine turned a propeller with a diameter of 11 feet, 3 inches (3.429 meters).

Hawker Monoplane F.36/34 K5083 (BAE Systems)

The Mk.I’s best economical cruising speed was 212 miles per hour (341 kilometers per hour) at 20,000 feet (6,096 meters), and its maximum speed was 316 miles per hour (509 kilometers per hour) at 17,750 feet (5,410 meters) and 6,440 pounds (2,921 kilograms). The airplane’s range was 585 miles (941 kilometers). The Hurricane Mk.I could climb to 20,000 feet in 9.7 minutes.

The fighter was armed with eight Browning .303 Mark II machine guns mounted in the wings, with 334 rounds of ammunition per gun.

“No. 111 Squadron was responsible for the introduction of the Hurricane to the RAF with the first aircraft arriving at Northolt in December 1937, in advance of the official acceptance date of 1 January 1938. The CO, S/Ldr John Gillan, flew L1555 in record time from Edinburgh to Northolt on 10 February 1938.” (Daily Mail)

Peter Townsend described the Hurricane in his book, Duel of Eagles:

“. . . By December [1938] we had our full initial equipment of sixteen aircraft. The Fury had been a delightful play-thing; the Hurricane was a thoroughly war-like machine, rock solid as a platform for eight Browning machine-guns, highly manoeuvrable despite its large proportions and with an excellent view from the cockpit. The Hurricane lacked the speed and glamour of the Spitfire and was slower than the Me. 109, whose pilots were to develop contempt for it and a snobbish preference for being shot down by Spitfires. But figures were to prove that during the Battle of Britain, machine for machine, the Hurricane would acquit itself every bit as well as the Spitfire and in the aggregate (there were more than three Hurricanes to two Spitfires) do greater damage among the Luftwaffe.”

Duel of Eagles, Group Captain Peter Wooldridge Townsend, CVO, DSO, DFC and Bar, RAF. Cassell Publishers Limited, London, Chapter 13 at Pages 153–154. 

Hawker Hurricanes at Brooklands. (BAE Systems)

At the beginning of World War II, 497 Hurricanes had been delivered to the Royal Air Force, enough to equip 18 squadrons. During the Battle of Britain, the Hurricane accounted for 55% of all enemy aircraft destroyed. Continuously upgraded throughout the war, it remained in production until July 1944. The final Hurrican, a Mk.IIc, PZ865, was flown for the first time by P.W.S. Bulman on 24 July 1944. A total of 14,503 were built by Hawker Aircraft Ltd., Gloster Aircraft Company, Austin Motor Company, and the Canadian Car and Foundry Company.

The final Hawker Hurricane, a Mk.IIc, PZ865, “The Last of the Many!” Chief Test Pilot P.W.S. “George” Bulman also took this fighter for its first flight, 22 July 1944. (BAE Systems)
P.W.S. Bulman with PZ865, July 1944.
Group Captain “George” Bulman flying the final Hawker Hurricane, PZ865, a Mk.IIc.

¹ Later, Group Captain Paul Ward Spencer Bulman, C.B.E., M.C., A.F.C. and Bar.

© 2018, Bryan R. Swopes

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2 November 1953

Air Force officers examine the wreck of teh prototype Convair YF-102, 52-994, near Edwards AFB, 2 November 1953. (San Diego Air and Space Museum Archives)
Air Force officers examine the wreck of the prototype Convair YF-102, 52-7994, near Edwards AFB, 2 November 1953. (San Diego Air and Space Museum Archives)

On 2 November 1953, the Convair YF-102 prototype, 52-7994 was severely damaged when its Pratt & Whitney J57-P-11 engine flamed out during a test flight. The cause was traced to the engine’s Bendix fuel control. Dick Johnson was unable to restart the engine and was forced to make a gear-up landing in the desert, not far from Edwards Air Force Base. Johnson was seriously injured. The prototype was written off.

Wreck of Convair YF-102 52-7994 near Edwards Air Force Base, 2 November 1953. (San Diego Air and Space Museum Archives)
Wreck of Convair YF-102 52-7994 near Edwards Air Force Base, 2 November 1953. (San Diego Air and Space Museum Archives)

© 2016, Bryan R. Swopes

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31 October 1959

Colonel Georgy Konstantinovich Mosolov
Colonel Georgy Konstantinovich Mosolov

31 October 1959: At Joukovski-Petrovskoe, U.S.S.R., Гео́ргий Константи́нович Мосоло́в (Georgy Konstantinovich Mosolov), chief test pilot for Mikoyan-Gurevich, flew a prototype of the MiG-21 interceptor identified as the E-66, to set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 15/25 Kilometer Straight Course. His speed averaged 2,388 kilometers per hour (1,483.8 miles per hour).¹

The МиГ-21 prototype identified by the symbol E-66  is known at the Mikoyan Design Bureau as the E-6\3. Its first flight took place in December 1958. It is powered by a Tumansky 11F-300 afterburning turbojet engine. (A Wikipedia article suggests that this airplane was rebuilt to different configurations several times, with designations changed accordingly.)

Mosolov’s FAI altitude record of 28 April 1961 was also flown in a MiG-21 prototype called E-66. (FAI Record File # 8661) Photographs and motion picture film of that airplane show it marked with red numerals “31” on the forward fuselage.

This photograph from the web site Wings of Russia is described as showing the Mikoyan-Gurevich Ye-6T/1 prototype, "31 Red", flown to a world record altitude, 28 April 1961.
The airplane in this  photograph from the web site “Wings of Russia” is described as showing the Mikoyan-Gurevich E-6T\1 prototype, “31 Red,” flown to a world record altitude by Colonel Mosolov, 28 April 1961.

Colonel Mosolov was interviewed for an article in Air & Space Smithsonian Magazine. He told writer Tony Reichhardt that after completing the speed record course, he was 125 miles (201 kilometers) from base at 44,000 feet (13,411 meters). Low on fuel, he shut down the turbojet engine and began a long glide. He twice unsuccessfully attempted to restart the engine for the landing, but was forced to glide all the way to the runway. After landing, the fuel system was drained. Only 8 liters (2.1 gallons) remained.

Colonel Georgy K. Mosolv, Soviet Air Forces. Hero of the Soviet Union.
Colonel Georgy Konstantinovich Mosolov, Soviet Air Forces. Hero of the Soviet Union.

Georgy Konstantinovich Mosolov was born 3 May 1926 at Ufa, Bashkortostan, Union of Soviet Socialist Republics. He was educated at the Central Aviation Club, where he graduated in 1943, and then went to the Special Air Forces School. In 1945 he completed the Primary Pilot School and was an instructor at the Chuguev Military Aviation School (Kharkiv, Ukraine). In 1953 Mosolov was sent to the Ministry of Industrial Aviation Test Pilot School at Ramenskoye Airport, southeast of Moscow, and 6 years later, to the Moscow Aviation Institute. He was a test pilot at the Mikoyan Experimental Design Bureau from 1953 to 1959, when he became the chief test pilot.

Georgy Mosolov set six world speed and altitude records. He was named a Hero of the Soviet Union, 5 October 1960.

On 11 September 1962, an aircraft that Colonel Mosolov was flying suffered a catastrophic compressor failure at Mach 2.15 and began to break apart. Severely injured, Mosolov ejected from the doomed airplane at Mach 1.78. He survived but his test flying career was over. His recovery took more than a year, and though he was able to fly again, he could not resume his duties as a test pilot.

Mikoyan-Gurevich Ye-152A, one of the MiG-21 prototypes flown by Georgy Mosolov.
This Mikoyan-Gurevich E-152A, NATO code name  “Flipper,” is one of the many MiG-21 prototypes flown by Georgy Mosolov.

¹ FAI Record File Number 9062

© 2017, Bryan R. Swopes

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