Reginal Mitchell

Some interesting facts about the Spitfire.

Speed and altitude records

Beginning in late 1943, high-speed diving trials were undertaken at Farnborough to investigate the handling characteristics of aircraft travelling at speeds near the sound barrier (i.e. the onset of compressibility effects). Because it had the highest limiting Mach number of any aircraft at that time, a Spitfire XI was chosen to take part in these trials. Due to the high altitudes necessary for these dives, a fully feathering Rotol propeller was fitted to prevent overspeeding. It was during these trials that EN409, flown by Squadron Leader J. R. Tobin, reached 606 mph (975 km/h, Mach 0.891) in a 45 degree dive. In April 1944 the same aircraft suffered engine failure in another dive while being flown by Squadron Leader A. F. Martindale, when the propeller and reduction gear broke off. Martindale successfully glided the Spitfire 20 miles (32 km) back to the airfield and landed safely.

"That any operational aircraft off the production line, cannons sprouting from its wings and warts and all, could readily be controlled at this speed when the early jet aircraft such as Meteors, Vampires, P-80s, etc could not, was certainly extraordinary.― Jeffrey Quill"

On 5 February 1952, a Spitfire 19 of No. 81 Squadron RAF based in Hong Kong reached probably the highest altitude ever achieved by a Spitfire. The pilot, Flight Lieutenant Ted Powles, was on a routine flight to survey outside air temperature and report on other meteorological conditions at various altitudes in preparation for a proposed new air service through the area. He climbed to 50,000 feet (15,240 m) indicated altitude, with a true altitude of 51,550 feet (15,712 m). The cabin pressure fell below a safe level, and in trying to reduce altitude, he entered an uncontrollable dive which shook the aircraft violently. He eventually regained control somewhere below 3,000 feet (900 m) and landed safely with no discernible damage to his aircraft. Evaluation of the recorded flight data suggested that, in the dive, he achieved a speed of 690 mph (1,110 km/h, Mach 0.94), which would have been the highest speed ever reached by a propeller-driven aircraft.

The critical Mach number of the Spitfire's original elliptical wing was higher than the subsequently-used laminar-flow-section, straight-tapering planform wing of the follow-on Supermarine Spiteful, Seafang and Attacker, illustrating that Reginald Mitchell's thoughtful and practical engineering approach to the problems of high speed flight had paid off handsomely.

That was a good read, that is a plane that sent shivers down anyones spine, just by the noise, nice one steve..thanks for the effort.

Mustang

"It can't quite do what the Spitfire does - But it does it over Berlin..."

In 1939, shortly after World War II began, the British government established a purchasing commission in the United States, headed by Sir Henry Self. Along with Sir Wilfrid Freeman, who, as the "Air Member for Development and Production", was given overall responsibility for RAF production and research and development in 1938, Self had sat on the (British) Air Council Sub-committee on Supply (or "Supply Committee"), and one of Self's many tasks was to organize the manufacture of American fighter aircraft for the RAF. At the time the choice was very limited: none of the U.S. aircraft already flying met European standards; only the Curtiss P-40 Tomahawk came close. The Curtiss plant was running at capacity, so even that aircraft was in short supply.

North American Aviation (NAA) was already supplying their Harvard trainer to the RAF, but were otherwise underutilized. NAA President "Dutch" Kindelberger approached Self to sell a new medium bomber, the B-25 Mitchell. Instead, Self asked if NAA could manufacture the Tomahawk under license from Curtiss.

Kindelberger replied that NAA could have a better aircraft with the same engine in the air in less time than it would take to set up a production line for the P-40. By now the executive head of the British Ministry of Aircraft Production (MAP), Freeman ordered 320 aircraft in March 1940. On 26 June 1940, MAP awarded a contract to Packard to build modified versions of the Rolls-Royce Merlin engines under licence; in September, MAP increased the first production order by 300

The result of the MAP order was the NA-73X project (from March 1940). The design followed the best conventional practice of the era, but included two new features. One was a new NACA-designed laminar flow wing, which was associated with very low drag at high speeds. Another was the use of a new radiator design (one Curtiss had been unable to make work) that used the heated air exiting the radiator as a form of jet thrust in what is referred to as the "Meredith Effect". Because North American lacked a suitable wind tunnel, it used the GALCIT 10-foot wind tunnel at Cal Tech. This led to some controversy over whether the Mustang's cooling system aerodynamics were developed by North American's engineer Edgar Schmued or by Curtiss, although historians and researchers dismiss the allegation of stolen technology; such claims are likely moot in any event, as North American had purchased Curtiss’ complete set of P-40 and XP-46 wind tunnel data and flight test reports for US$56,000.

While the United States Army Air Corps could block any sales it considered detrimental or not in the interest of the United States, the NA-73 represented a special case. In order to ensure deliveries were uninterrupted, an arrangement was eventually reached where the RAF would get its aircraft in exchange for NAA providing two free examples to the USAAC for evaluation.

The prototype NA-73X was rolled out just 117 days after the order was placed, and first flew on 26 October 1940, just 178 days after the order had been placed — an incredibly short gestation period. In general the prototype handled well and the internal arrangement allowed for an impressive fuel load. It was armed with four .30 caliber Browning (7.62 mm) and two .50 M2 Browning (12.7 mm) machineguns in the wings and two .50 M2s in the chin.

It was quickly evident that performance, although exceptional up to 15,000 feet, was markedly reduced at higher altitudes. This deficiency was due largely to the single speed, single stage supercharger of the Allison V-1710 engine, where power diminished rapidly above the critical altitude rating.

Merlin-engined Mustangs

In April 1942, the RAF's Air Fighting Development Unit (AFDU) tested the Mustang and found its performance inadequate at higher altitudes. As such it was to be used to replace the Tomahawk in Army Cooperation Command squadrons but the commanding officer was so impressed with its manoeuvrability and low-altitude speeds that he invited Ronnie Harker from Rolls Royce's Flight Test establishment to fly it. Rolls-Royce engineers rapidly realized that equipping the Mustang with a Merlin 61 engine with its two speed, two stage supercharger would substantially improve performance and started converting five aircraft as the Mustang X. Apart from the engine installation, which utilised custom built engine bearers designed by Rolls-Royce and a standard 10 ft 9 in diameter, four bladed Rotol propeller from a Spitfire Mk. IX ,the Mustang X was a straight-forward adaptation of the Mustang I airframe, keeping the same radiator duct design. The Vice-Chief of the Air Staff, Air Marshal Sir Wilfrid R. Freeman, lobbied vociferously for Merlin-powered Mustangs, insisting two of the five experimental Mustang Xs be handed over to Carl Spaatz for trials and evaluation by the U.S. 8th Air Force in Britain.

P-51B in flight showing wing planform.
USAAF P-51B-10-NAThe high-altitude performance improvement was astonishing: the Mustang X (AM208) reached 433 mph (697 km/h) at 22,000 ft and AL975 tested at an absolute ceiling of 40,600 ft.
The XP-51B prototypes were a more thorough adaptation of the airframe, with a tailor made engine installation and a complete redesign of the radiator duct. The airframe itself was strengthened, with the fuselage and engine mount area receiving more formers because of the greater weight of the Packard Merlin V-1650-3, 1,690 lbs compared with the Allison V-1710's 1,335 lbs. The engine cowling was completely redesigned to house the Packard Merlin which, because of the intercooler radiator mounted on the supercharger casing, was 5 inches taller and used an updraught induction system rather than the downdraught carburetor of the Allison. The new engine drove a four bladed 11 ft 2 in diameter Hamilton Standard propeller which featured cuffs of hard molded rubber. A new radiator, supercharger intercooler and oil radiator installation in a new fuselage duct was designed to cater for the increased cooling requirements of the Merlin.

One of the few remaining complaints with the Merlin-powered aircraft was a poor rearward view. This was a common problem in most fighter designs of the era, which had only been recognized by the British after the Battle of Britain proved the value of an all-around view. In order to improve the view from the Mustang at least partially, the British had field-modified some Mustangs with fishbowl-shaped sliding canopies called "Malcolm Hoods." Eventually all Mk IIIs, along with some American P-51B/Cs, were equipped with Malcolm Hoods.

A better solution to the problem was the "teardrop" or "bubble" canopy. Originally developed as part of the Miles M.20 project, these newer canopies were in the process of being adapted to most British designs, eventually appearing on late-model Spitfires, Typhoons and Tempests. North American adapted several NA-106 prototypes with a bubble canopy, cutting away the decking behind the cockpit, resulting in substantially improved vision to the rear.

This led to the production P-51D (NA-109), considered the definitive Mustang.

On 27 July 1942, sixteen RAF Mustangs undertook their first long-range reconnaissance mission over Germany. During Operation Jubilee, the Dieppe Raid (19 August 1942), four British and Canadian Mustang squadrons, including No. 26 Squadron RAF saw action. By 1943/1944, British Mustangs were used extensively to seek out V-1 sites. The final RAF Mustang I and Mustang II machines were struck off charge in 1945. The RAF operated several Mustang III (P-51B/C) machines, the first units converting to the type in late 1943/1944. Mustang III units were operational until the end of World War II, though many units had already converted to the Mustang IV (P-51D/K). RAF pilots preferred the Mustang III (with Malcolm hood), but the RAF re-equipped with Mustang IVs. As the Mustang was a Lend-Lease type, all aircraft still on RAF charge at the end of the war were either returned to the USAAF "on paper" or retained by the RAF for scrapping. The final Mustangs were retired from RAF use in 1947.

Some interesting points to note.

Used in Korea by the USAF, 77 Sqn RAAF and 2 Sqn SAAF. 77 Sqn (which included quite a few seconded RAF pilots) converted to Meteor F.8s in 1951 while 2 Sqn and its parent 18th Fighter-Bomber Wing USAF used the Mustang until late '52/early '53, only converting to Sabres for the last 6 months of the war.

The Mustang was adopted by many foreign air forces and continued to be an effective fighter into the mid 1980s with smaller air arms. The last Mustang ever downed in battle occurred during Operation Power Pack in the Dominican Republic in 1965, with the last aircraft finally being retired by the Dominican Air Force in 1984

Hawker Hurricane

The Hawker Hurricane was developed by Sidney Camm. As a fighter plane, the Hawker Hurricane was to revolutionise all future fighter plane design. It was to play a vital role in the Battle of Britain and eventually in many other theatres of World War Two.

The Hurricane first made its mark in February 1938. In this month, a Hurricane piloted by Squadron Leader J W Gillan, commanding officer of 111 Squadron, had flown from Scotland to Northholt, a distance of 327 miles, in 48 minutes at an average speed of 409 mph (admittedly with a tail wind).

The history of the Hurricane went back to 1933 when Sidney Camm discussed with the Air Ministry the possibilities of producing a monoplane fighter. At this time, the Air Ministry was not keen on a monoplane despite the fact that a monoplane had established a world speed record of 423 mph (an Italian Macchi MC.72) in April 1933.

The first prototype Hurricane flew on November 6th 1935. It had been based on the design of the Fury plane built by Hawker and was powered by a Rolls-Royce Merlin engine. In February 1936, the Hurricane exceeded all of the demands placed on it and on June 3rd 1936, the Air Ministry placed an order for 600 Hurricane fighter planes. On October 12th, 1937, the first flight of a production Hurricane took place. By the end of 1938, 200 Hurricanes had been delivered to the RAF’s Fighter Command.

In September 1939, 19 RAF squadrons had been equipped with Hurricanes. A Hurricane was the first RAF plane to destroy a Luftwaffe plane in October 1939 when Pilot Officer Mould shot down a Dornier Do-17 over France. It was to prove a short-term success. In the German attack on France in the Spring of 1940, 25% of all Hurricanes were destroyed by the Luftwaffe (some 200 planes).

In was in the Battle of Britain that the Hurricane made its mark. The battle is frequently associated with the Spitfire, but the Hurricane played a major role in this battle. On August 8th, 1940, the RAF could call on 32 squadrons of Hurricanes and 19 of Spitfires. Therefore, the Hurricane was the dominant British plane in this battle.

Hurricane pilots at Hawkinge waiting for their next flight

Though slower than the Spitfire, the Hurricane developed a reputation as a plane that could take more than a few hits from the Germans and continue to fly. To some the Spitfire was a thoroughbred horse; superb until it was damaged. The Hurricane, though less graceful and slower than the Spitfire, was more a shire horse; incredibly strong and capable of taking many hits before it was taken out.

"It was a delightful aeroplane - not as agile as a Spitfire, but it had a very good gun platform. It was very steady and took a tremendous amount of battle damage without appearing to worry too much."
Pilot officer R G A Barclay

The Hurricane, in various guises, saw combat in most areas of World War Two – the jungles of the Far East, the deserts of North Africa etc. Almost 3000 Hurricanes were delivered to Russia during the war. In total, more than 14,000 Hurricanes fought in World War Two in all theatres of war – a remarkable achievement for a remarkable plane.

Facts:

Crew: 1

Maximum speed: 328 mph (550 km/h) at 22,000 feet (6705 meters)

Ceiling: 36,500 feet (11,125 metres)

Range: 480 miles (772 km)

Armaments: 8 x 0.303 machine guns.