Tag Archives: Rolls-Royce Merlin C

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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5 March 1936

The Vickers-Supermarine Type 300, K5054, during its first flight, 5 March 1936. The pilot is Captain Joseph Summers. (Supermarine Aviation Works)

5 March 1936: At 4:35 p.m., Thursday afternoon, Vickers Aviation Ltd.’s Chief Test Pilot, Captain Joseph (“Mutt”) Summers, took off on the first flight of the Vickers-Supermarine Type 300, K5054, prototype of the legendary Supermarine Spitfire, at Eastleigh Aerodrome, Southampton, England. Landing after only 8 minutes, Summers is supposed to have said, “Don’t change a thing!”

Supermarine Type 300 K5054. © IWM (ATP 8770C)
Supermarine Type 300 K5054. © IWM (MH 5215)
Supermarine Type 300 K5054. © IWM (MH 5212)
Supermarine Type 300 K5054. © IWM (ATP 8770G)

The Vickers-Supermarine Type 300 was a private venture, built to meet an Air Ministry requirement¹ for a new single-place, single-engine interceptor for the Royal Air Force. The airplane was designed by a team led by Reginald Joseph Mitchell, C.B.E., F.R.Ae.S., and was built at the Supermarine Aviation Works, Southampton, Hampshire, England.

Vickers-Supermarine Type 300, K5054. (Supermarine Aviation Works)

R.J. Mitchell was famous for his line of Schneider Trophy-winning and world record-setting Supermarine racers of the late 1920s and early 1930s, the Supermarine S.4, S.5, S.6 and S.6B.² Mitchell was appointed Commander of the Most Excellent Order of the British Empire  (Civil Division) (CBE) in His Majesty’s New Year’s Honours, 2 January 1932, for “services in connection with the Schneider Trophy Contest.”

Reginald Joseph Mitchell, C.B.E., F.R.Ae.S.

The Vickers-Supermarine Type 300 was 29 feet, 11 inches (9.119 meters) long, with a wingspan of 36 feet, 10 inches (11.227 meters) and overall height of 12 feet, 8 inches (3.861 meters). The wings had a distinctively ellipsoid shape, area was 242.0 square feet (22.48 square meters). Its empty weight was 4,082 pounds (1,151.6 kilograms) and loaded weight was 5,359 pounds (2,430.8 kilograms).

Supermarine Type 300 K5054. © IWM (MH 5205)

K5054 was powered by a right-hand tractor, liquid-cooled, supercharged, 1,648.9-cubic-inch-displacement (27.04-liter) Rolls-Royce Merlin C (“ramp head”) single overhead camshaft (SOHC) 60° V-12 engine, serial number C9 (Air Ministry serial number A111,139), which 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 (0.41 Bar). The engine turned aan Airscrew Co., Ltd., Watts-type two-bladed, fixed-pitch, compressed wood propeller through a gear reduction drive (possibly 0.420:1). (K5083, the prototype Hawker Hurricane, was also equipped with a Merlin C.) An improved 1,035 horsepower Merlin F engine, serial number F21 (Air Ministry serial number A115,73 ), was later installed.

Interestingly, Rolls-Royce discovered that using exhaust stacks to direct the flow of gases rearward provided an additional 70 pounds of thrust, an increase of 7% over that provided by the propeller alone. Later testing of K5054 with “fish tail” exhaust stacks increased its top speed to about 360 miles per hour (579 kilometers per hour).

Supermarine Type 300 K5054. © IWM (MH 5213)
Supermarine Type 300 K5054. © IWM (ATP 8321D)
The prototype Vickers-Supermarine Type 300, K5054, in light blue lacquer paint. (RAF Museum)

The Type 300 had a cruise speed of 311 miles per hour ( kilometers per hour) at 15,000 feet (4,572 meters), and could reach that altitude in 5 minutes, 52 seconds. maximum speed of 349 miles per hour (562 kilometers per hour) at 16,800 feet (5,121 meters). The prototype had a service ceiling of 35,400 feet (10,790 meters).

A report summarizing the flight testing of K5054 stated, “The aeroplane is simple and easy to fly and has no vices.” Visibility was good, the cockpit was comfortable, and it was a stable gun platform.

 K5054 after crash landing at Matrlesham Heath, 22 March 1937. (Solent Sky Museum)
K5054 after forced landing at Martlesham Heath, 22 March 1937. Note the “fish tail” exhaust stacks. (Solent Sky Museum)

On 22 March 1937, K5054’s engine lost oil pressure and the pilot made a belly landing on Marlesham Heath. The Spitfire was damaged, but was repaired and returned to service.

The prototype Spitfire stalled on landing at RAE Farnborough, 4 September 1939. After several bounces on the runway, it nosed over. The pilot, Flight Lieutenant Gilbert Stanbridge (“Spinner”) White, was severely injured. He died 9 September.

K5054 was disassembled and scrapped.

The Air Ministry ordered the Spitfire Mk.I into production before K5054’s first flight, with an initial order for 310 airplanes. The first production fighter was delivered to the Royal Air Force 4 August 1938. Between 1938 and 1948, 20,351 Spitfires were built in 24 variants.

Supermarine Spitfire of the Royal Air Force Battle of Britain Memorial Flight. (Royal Air Force)
Captain Joseph Summers

Captain Joseph Summers, C.B.E., was born 10 March 1904. He was the older brother of Group Captain Maurice Summers, who was also a test pilot for Vickers. In 1922, he married Miss Dulcie Jeanette Belcher at Sculcoates, Yorkshire. They would have several children.

In 1924, Summers received a short-service commission as an officer in the Royal Air Force. He trained as a pilot with No. 2 Flight Training Squadron, at RAF Duxford. He was hospitalized for six months, which delayed his training, but he graduated in 1924 and was assigned to No. 29 Fighter Squadron. Summers was considered to be an exceptional pilot, and with just six months’ operational experience, he was assigned as a test pilot at the Aircraft and Armaments Engineering Establishment (A&AEE) at RAF Martlesham Heath. He remained there for the reminder of his military service. In June 1929 he became a test pilot for Vickers Ltd. (Aviation Department). He became the company’s chief test pilot in 1932.

During his career as a test pilot, “Mutt” Summers made the first flights of 54 prototype aircraft, including the Spitfire, the Vickers Type 618 Nene-Viking, the Vickers Type 630 Viscount four-engine turboprop airliner, and the Vickers Type 667 Valiant, a four-engine jet bomber. He flew more than 5,600 hours in 366 different aircraft types.

“Mutt’s approach to test flying was much more in sympathy with the knee-pad than with the complicated automatic observers which nowadays are an indispensable part of test flying. He vigorously defended the feel of an aeroplane as measured by his hand or by the seat of his pants, and I believe was always suspicious of the scientific approach. . . One learned never to regard his criticism or advice lightly. In a world of science and instrumentation his judgement and horsesense often threw an unscientific but accurate light on some dark problem.” —Sir George R. F. Edwards, OM, CBE, FRS, DL, Executive Director of the British Aircraft Corporation, quoted in Flight and Aircraft Engineer, No. 2357, Vol. 65, Friday, 26 March 1954, at Page 355, Column 2.

Joseph Summers, Esq., was appointed an Officer of the Most Excellent Order of the British Empire, Civil Division (O.B.E.), in His Majesty’s New Year’s Honours, Wednesday, 9 January 1946. He was promoted to Commander of the Most Excellent Order of the British Empire (Civil Division) (C.B.E.) in Her Majesty’s Coronation Honours, Monday, 1 June 1953.

Summers died 16 March 1954 at the age of 50 years.

¹ Air Ministry Specification F.37/34 High Speed Monoplane Single Seater Fighter

² FAI Record File Number 11833, World Record for Speed Over a 3-Kilometer Course: 364.92 kilometers per hour (226.75 miles per hour). Supermarine S.4, Henri Biard, 13 September 1925.

FAI Record File Number 14999, World Record for Speed Over 100 Kilometers: 531.20 kilometers per hour (330.07 miles per hour), Supermarine S.6, Henry Richard Danvers Waghorn, 7 September 1929.

FAI Record File Number 11831, World Record for Speed Over a 3-Kilometer Course: 655 kilometers per hour (407 miles per hour), Supermarine S.6B, George Hedley Stainforth, 29 September 1931.

© 2018, Bryan R. Swopes

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