Supermarine S.6

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S.6
R.J. Mitchell
ServiceRoyal Air Force High Speed Flight
Number built2
History
First flight1929
Retired1931
SuccessorsSupermarine S.6B

The Supermarine S.6 (later designated the S.6A) is a 1920s British single-engined single-seat racing

R.J. Mitchell, who refined the earlier Supermarine S.5 to produce a larger, more powerful aircraft. Two aircraft, N247 and N248, were built to participate in the 1929 Schneider Trophy contest. Rolls-Royce produced the R engine for the new all-metal aircraft. The engine's initial issues—such as the short time between overhauls and the heat generated when the engine power was increased to 1,900 hp (1,400 kW)—were resolved within a few months before the aircraft were completed at Supermarine’s works at Woolston, Southampton
.

The day before the 1929 race, one of N247's pistons was discovered to be faulty; the piston was replaced during the night. The race on the following day was won by the British team, with N247 coming first at a speed of 328.63 miles per hour (528.88 km/h), whilst N248 set World closed-circuit records for 50 and 100 kilometres (31 and 62 mi). For the 1931 race, the S.6 was redesigned as the Supermarine S.6B, to take a more powerful version of the R engine. The two existing S.6s were brought up to a similar standard as the S.6Bs, but N247 was destroyed prior to the contest during a fatal accident. The S.Bs were retired after the 1931 contest. The surviving S.6A is on display at the Solent Sky museum in Southampton.

Design and development

drawing of the S.6 with labels
An illustration of the S.6 from Popular Mechanics (December, 1929)

Following the success of the

R.J. Mitchell designed its successor, the Supermarine S.6, to Specification 8/28.[note 1] Refining the design of the earlier S.5, Mitchell designed a larger all-metal aircraft. The metal-framed wings of the S.6 were designed to be made using aluminium, so as to assist in reducing the overall weight of the aircraft. To achieve the required lift, the wings were made to be 3 feet (0.91 m) longer than those of the lighter S.5.[2]

The aircraft industry during the First World War had used up nearly all the world supply of seasoned spruce, a requirement for wooden aeroplanes at that time, and so the ability to produce metal-built aircraft for any future conflict was deemed by the British government to be essential.[3]

An innovation by Mitchell was the use of duralumin radiators on the surface of the wings. Made both to withstand forces that tended to cause the wings to twist, and to minimise air resistance, they were made of two thicknesses of metal that allowed water to pass between them.[4]

Rolls-Royce R engine

Main article: Rolls-Royce R

As the 875

rpm.[3] The engine needed 160 imperial gallons (730 L; 190 US gal) of petrol to complete a race, as it consumed fuel at a rate of 3.6 imp gal/min (0.27 litres per second).[7] By July 1928, Mitchell had been given drawings of the engine from Rolls-Royce, which he used to work on improving the aerodynamic qualities of the aircraft.[8]

To help alleviate problems of engine cooling caused by the high rate of heat generation, the S.6 had surface radiators built into the floats as well as on the wings. Additional cooling was provided by means of air flowing through the internal structure of the wings.[5] The new engine weighed 1,530 pounds (690 kg), a weight that meant that it had to be better supported by moving the float struts forward by a slight amount. The increase in fuel consumption meant that both floats had to incorporate steel fuel tanks.[4][9]

In February 1929, Supermarine was authorised to build two machines for the 1929 contest.

serial numbers N247 and N248) were built together at their works at Woolston, Southampton.[10]

Operational history

The 1929 Schneider Trophy course

The two S.6s were delivered to Calshot in August 1929 for operation by the RAF High Speed Flight.[5] N247 first flew on 10 August, and N248 a fortnight later.[10] Soon after N247 arrived at Calshot, it was found that one of the floats was so low in the water on take-off that it made the aircraft rotate on the surface. Ripples were sufficient to enable N247 to become airborne. An issue with overheating was sorted by installing extra radiators.[11]

When a British entrant, a Gloster VI was forced by engine trouble to be withdrawn, the only two British entrants that remained were the S.6s, and so the S.5 (N219) was prepared for the contest.[11] During a final check of N247, a speck of metal was discovered on a spark plug, which revealed a faulty piston. It was forbidden for the entire engine to be replaced once it was installed, but components could be changed prior to the race. The engine block was changed during the night—by specialist Rolls-Royce engineers from a party who happened to have come down to Southampton from Derby to watch the race—so that the engine was running smoothly by the start of the next day.[12]

The 1929 Schneider Trophy race took place off the English coast north of the

Ramsay McDonald publicly pledged official support for the 1931 contest, a decision that was later reversed by the government.[13]

For the 1931 Schneider Trophy race, also to be held at Calshot, the S.6 was adapted to take a more powerful 2,350 horsepower (1,750 kW) version of the R engine. Two new aircraft, designated the Supermarine S.6B, were built. The two existing S.6s, now designated as S.6As, were provided with new floats, additional cooling areas and statically-balanced control surfaces. All four aircraft were brought up to a similar standard.[14] During the initial flight of the improved N247 on 2 June, the pilot experience dangerous levels of tail flutter (a form of resonance), which was only alleviated when masses were fixed to the rudder.[15]

The British plan for the 1931 contest was to fly one of the S.6Bs, S1595, around the course alone, with N248 in reserve. If both S1595 and N248 failed in their attempts, N247 would be used. However, N247, flown by Navy Lieutenant G.N. Brinton, was destroyed in a fatal takeoff accident during a pre-contest training exercise. N248 remained as part of the team but did not fly in the race. S1595 went on to win a race in which only British aircraft participated.[16]

Aircraft on display

The surviving Supermarine S.6 (N248) at the Solent Sky museum in Southampton

N248 was used in the 1942 British biographical film about Mitchell, The First of the Few.[17] Until the 1960s, the aircraft was displayed incorrectly as S.6B S1596 as a visitor attraction in a building adjacent to the Royal Pier, Southampton. The S.6A was restored from 1983 onwards, and repainted in its original 1931 scheme. It can be seen on display at the Solent Sky museum in Southampton.[18]

Operators

 United Kingdom

Specifications (N247)

Data from Supermarine Aircraft since 1914 (1981)[19]

General characteristics

  • Crew: 1
  • Length: 25 ft 10 in (7.87 m) overall; 25 ft 3 in (7.70 m) fuselage only
  • Wingspan: 30 ft 0 in (9.14 m)
  • Height: 12 ft 3 in (3.73 m)
  • Wing area: 145 sq ft (13.5 m2)
  • Airfoil: RAF 27[20]
  • Empty weight: 4,471 lb (2,028 kg)
  • Gross weight: 5,771 lb (2,618 kg)
  • Powerplant: 1 × Rolls-Royce R V-12 liquid-cooled piston engine, 1,900 hp (1,400 kW) at 2,900 rpm for one hour
  • Propellers: 2-bladed fixed-pitch propeller

Performance

  • Maximum speed: 357.7 mph (575.7 km/h, 310.8 kn) (World speed record at the time)
  • Alighting speed: 95 mph (83 kn; 153 km/h)

See also

Related development

Related lists

Notes

  1. ^ The order for the aircraft was placed on 3 May, 1929, under contract S27042/28.[1]
  2. ^ The changes made to the Buzzard involved the inclusion of a new supercharger, the strengthening of the engine to deal with greater mechanical stresses, and modifications to enable the engine to fit the streamlined shape of the S.6.[6]

References

Citations

  1. ^ Andrews & Morgan 1981, p. 357.
  2. ^ Shelton 2008, pp. 104–105.
  3. ^ a b c d Eves & Coombs 2001, p. 176.
  4. ^ a b National Advisory Committee for Aeronautics 1931, p. 1.
  5. ^ a b c d Green 1967, p. 745.
  6. ^ a b Andrews & Morgan 1981, p. 187.
  7. ^ Eves & Coombs 2001, p. 177.
  8. ^ Shelton 2015, p. 104.
  9. ^ Shelton 2008, p. 105.
  10. ^ a b Andrews & Morgan 1981, p. 191.
  11. ^ a b James 1981, p. 38.
  12. ^ James 1981, pp. 39, 143.
  13. ^ a b Andrews & Morgan 1981, p. 194.
  14. ^ Green 1967, p. 746.
  15. ^ Andrews & Morgan 1981, p. 198.
  16. ^ "Supermarine S6 and S6B". BAE Systems. Archived from the original on 10 May 2022. Retrieved 16 February 2024.
  17. ^ Mitchell 2002, p. 232.
  18. ^ Glancey 2020, p. 321.
  19. ^ Andrews & Morgan 1981, pp. 173–203.
  20. ^ Lednicer, David (28 September 2023). "The Incomplete Guide to Airfoil Usage". UIUC Applied Aerodynamics Group. Retrieved 16 February 2024.

Sources

Further reading

External links

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