Originally Posted by
Top_Gunn
Not the Tornado, but the story of the Rolls Royce Vulture engine, although not directly relevant to this airplane, is at least similar to the events that led to the low production figures for this plane. So I'll add a clue. (Did I mention that clue 8 tells you three things about the airplane?)
Looking for the name of an airplane.
1. Not many produced: Under 200, which was very few for a successful airplane of its type at the time.
2. But the low production number was not was not due to poor performance.
3. It was fast, maneuverable, and heavily armed.
4. Crew of one.
5. Although few were produced, the plane's wartime service lasted a little over two years.
6. Most of that wartime service consisted of ground attack.
7. Pilots liked it because it was easy to fly and visibility from the cockpit was unusually good for a plane that first flew when this one did.
8. It was better suited to ground attack than to the fighter role because it had limited range and its engines functioned poorly at high altitudes.
9. The previous clue contains a somewhat subtle clue in addition to the ones about range and altitude.
10. Its low production numbers were due to the unavailability of the only engine that suited its design.
Well, you've never actually said it was a single engine fighter/fighter bomber; so... How about the Whirlwind? Thanks; Ernie P.
The Westland Whirlwind was a British twin-engined heavy fighter developed by Westland Aircraft. A contemporary of the Supermarine Spitfire and Hawker Hurricane, it was the first single-seat, twin-engined, cannon-armed fighter of the Royal Air Force. When it first flew in 1938, the Whirlwind was one of the fastest combat aircraft in the world, and with four Hispano-Suiza 404 autocannon in its nose, the most heavily armed.
Protracted development problems with its Rolls-Royce Peregrine engines delayed the project and few Whirlwinds were built. During the Second World War, only three RAF squadrons were equipped with the Whirlwind but despite its success as a fighter and ground attack aircraft, it was withdrawn from service in 1943.By the mid-1930s, aircraft designers around the world perceived that increased attack speeds were imposing shorter firing times on fighter pilots. This implied less ammunition hitting the target and ensuring destruction. Instead of two rifle-calibre machine guns, six or eight were required; studies had shown that eight machine guns could deliver 256 rounds per second.[4]
The eight machine guns installed in the Spitfire and the Hurricane fired rifle-calibre rounds, which did not deliver enough damage to quickly knock out an opponent. Cannon, such as the French 20 mm Hispano-Suiza HS.404, which could fire explosive ammunition, offered more firepower and attention turned to aircraft designs which could carry four cannon. While the most agile fighter aircraft were generally small and light, their limited fuel storage also limited their range and tended to restrict them to defensive and interception roles. The larger airframes and bigger fuel loads of twin-engined designs were therefore favoured for long-range, offensive roles.
The first British specification for a high-performance machine-gun monoplane was F.5/34 but the aircraft produced were overtaken by the development of the new Hawker and Supermarine fighters.[5] The RAF Air Staff thought that an experimental aircraft armed with the 20 mm cannon was needed urgently and Air Ministry specification F.37/35 was issued in 1935. The specification called for a single-seat day and night fighter armed with four cannon. The top speed had to be at least 40 mph (64 km/h) greater than that of contemporary bombers – at least 330 mph (530 km/h) at 15,000 ft (4,600 m).[6]
[7]
Eight aircraft designs from five companies were submitted in response to the specification. Boulton Paul offered the P.88A and P.88B (two related single engine designs), Bristol the single-engined Type 153 and the twin-engined Type 153A. Hawker offered a variant of the Hurricane, the Supermarine 312 was a variant of Spitfire and the Supermarine 313 a twin-engined design with four guns in the nose and potentially a further two firing through the propeller hubs, the Westland P.9 had two Rolls-Royce Kestrel K.26 engines and a twin tail.[8]
[9] When the designs were considered in May 1936, there was concern that two engines would be less manoeuvrable than a single-engined design and that uneven recoil from cannon set in the wings would give less accurate fire. The conference favoured two engines with the cannon set in the nose and recommended the Supermarine 313.[10]
Although Supermarine's efforts were favoured due to their success with fast aircraft and the promise of the Spitfire which was undergoing trials, neither they nor Hawker were in a position to deliver a modified version of their single-engined designs quickly enough. Westland, which had less work and was further advanced in their project, was chosen along with the P.88 and the Type 313 for construction. A contract for two P.9s was placed in February 1937 which were expected to be flying in mid-1938. The P.88s were ordered in December along with a Supermarine design to F37/35 but both were cancelled in January.[10] Westland's design team, under the new leadership of W. E. W. "Teddy" Petter (who later designed the English Electric Canberra, Lightning and Folland Gnat) designed an aircraft that employed state-of-the-art technology. The monocoque fuselage was tubular, with a T-tail at the end, although as originally conceived, the design featured a twin tail, which was discarded when large Fowler flaps were added that caused large areas of turbulence over the tail unit.[11] The elevator was moved up out of the way of the disturbed airflow caused when the flaps were down.[11] Handley Page slats were fitted to the outer wings and to the leading edge of the radiator openings; these were interconnected by duraluminium torque tubes.[12]
In June 1941, the slats were wired shut on the recommendation of the Chief Investigator of the Accident Investigation Branch, after two Whirlwinds crashed when the outer slats failed during hard manœuvering; tests by the A&AEE confirmed that the Whirlwind's take-off and landing was largely unaffected with the slats locked shut, while the flight characteristics improved under the conditions in which the slats normally deployed.[13] The engines were developments of the Rolls-Royce Kestrel K.26, later renamed Peregrine. The first prototype, L6844, used long exhaust ducts that were channelled through the wings and fuel tanks, exiting at the wing's trailing edge. This configuration was quickly changed to more conventional, external exhausts after Westland's Chief test pilot Harald Penrose nearly lost control when an exhaust duct broke and heat-fractured an aileron control rod.[14] The engines were cooled by ducted radiators, which were set into the leading edges of the wing centre-sections to reduce drag.[15] The airframe was built mainly of stressed-skin duraluminium, with the exception of the rear-fuselage, which used a magnesium alloy stressed skin.[16]
[15]
With the pilot sitting high under one of the world's first full bubble canopies and the low and forward location of the wing, all round visibility was good (except for directly over the nose). Four 20 mm cannon were mounted in the nose; the 600 lb/minute fire rate made it the most heavily armed fighter aircraft of its era.[17][[i]clarification needed] The clustering of the weapons also meant that there were no convergence problems as with wing-mounted guns. Hopes were so high for the design that it remained "top secret" for much of its development, although it had already been mentioned in the French press.L6844 first flew on 11 October 1938, construction having been delayed chiefly due to the new features and also because of the late delivery of the engines.[15] L6844 was passed to RAE Farnborough at the end of the year, while further service trials were later carried out at Martlesham Heath.[18]
The Whirlwind exhibited excellent handling characteristics and proved to be very easy to fly at all speeds. The only exception was the inadequate directional control during take-off which necessitated an increased rudder area above the tailplane.[11]Whirlwind I undergoing fighter-bomber trials at the A&AEE. The Whirlwind was quite small, only slightly larger than the Hurricane but smaller in terms of frontal area. The landing gear was fully retractable and the entire aircraft was very "clean" with few openings or protuberances. Radiators were in the leading edge on the inner wings rather than below the engines. This careful attention to streamlining and two 885 hp Peregrine engines powered it to over 360 mph (580 km/h), the same speed as the latest single-engine fighters.[11] The aircraft had short range, under 300 mi (480 km) combat radius, which made it marginal as an escort. The first deliveries of Peregrine engines did not reach Westland until January 1940. By late 1940, the Supermarine Spitfire was scheduled to mount 20 mm cannon so the "cannon-armed" requirement was being met and by this time, the role of escort fighters was becoming less important as RAF Bomber Command turned to night flying.
The main qualities the RAF were looking for in a twin-engine fighter were range and carrying capacity (to allow the large radar apparatus of the time to be carried), in which requirements the Bristol Beaufighter could perform just as well as or even better than the Whirlwind. Production orders were contingent on the success of the test programme; delays caused by over 250 modifications to the two prototypes led to an initial production order for 200 aircraft being held up until January 1939, followed by a second order for a similar number, deliveries to fighter squadrons being scheduled to begin in September 1940.[19] Earlier, due to the lower expected production at Westland, there had been suggestions that production should be by other firms and an early 1939 plan to build 600 of them at the Castle Bromwich factory was dropped in favour of Spitfire production.[15]
[20]
Despite the Whirlwind's promise, production ended in January 1942, after the completion of just two prototypes and 112 production aircraft. Rolls-Royce needed to concentrate on the development and production of the Merlin, and the troubled Vulture, rather than the Peregrine.[21] Westland was aware that its design – which had been built around the Peregrine – was incapable of using anything larger without an extensive redesign.[22] After the cancellation of the Whirlwind, Petter campaigned for the development of a Whirlwind Mk II, which was to have been powered by an improved 1,010 hp Peregrine, with a better, higher-altitude supercharger, also using 100 octane fuel, with an increased boost rating.[nb 1]This proposal was aborted when Rolls-Royce cancelled work on the Peregrine.[25][nb 2] Building a Whirlwind consumed three times as much alloy as a Spitfire.[24]
Last edited by Ernie P.; 01-30-2018 at 11:45 AM.