| S.5 | |
|---|---|
 | |
| The first S.5 (N219) atCalshot during preparations for the 1929 Schneider Trophy Contest | |
| Role | Racing seaplane Type of aircraft |
| National origin | United Kingdom |
| Manufacturer | Supermarine |
| Designer | Reginald Mitchell |
| First flight | 7 June1927 |
| Introduction | 1927 |
| Primary user | Royal Air ForceHigh Speed Flight |
| Number built | 3 |
| Developed from | Supermarine S.4 |
TheSupermarine S.5 was a 1920sBritish single-engined single-seat racingseaplane built bySupermarine. Designed specifically for theSchneider Trophy competition, the S.5 was the progenitor of a line of racing aircraft that ultimately led to the iconicSupermarine Spitfire fighter of theSecond World War
The S.5 was designed byReginald Mitchell after the loss of theS.4 before it ever raced. It featured extensive changes from the S.4, possessing numerous unconventional features and making greater use of metal; many of these decisions were made to optimise its racing performance. Due to the short development window, a wooden wing was used rather than an all-metal one. In particular, it possessed a relatively low level ofdrag for the era.
On 7 June 1927, the first S.5 performed itsmaiden flight; a total of three aircraft were built. Two S.5s came in 1st and 2nd places at the 1927 Schneider Trophy contest; the type would also participate in the event during subsequent years. On 12 March 1928, one S.5 fatally crashed during an attempt on the world air speed record, killing the pilotFlight LieutenantSamuel Kinkead.[1][2] During the 1970s, a full-scale flight-worthy S.5 replica was constructed.
The Supermarine S.5 was designed byReginald Mitchell for the 1927 Schneider Trophy. Following the earlier loss of theS.4 before the 1925 Schneider Trophy was held, Mitchell designed a new monoplane racer. Extensive changes were made between the S.4 and S.5, the principal goal of which was to achieve greater speeds.[2] The design process was heavily influenced bywind tunnel testing, the resulting information from which was kept confidential for some time. The S.5 possessed a particularly low level ofdrag for afloatplane of the era.[3] Furthermore, the resulting aircraft possessed numerous unorthodox features, some of which were developed to meet specific conditions encountered during high speed air races.[4]
The fuselage of the S.5 was entirely composed of metal, primarilyduralumin; the strength of this material enabled the use of semi-monocoque construction, an arrangement that substantially reduced the amount of space taken up by the fuselage.[4] In turn, the cross section of the fuselage could be minimised, to the extent that the pilot was seated on the floor of the fuselage while their shoulders were in contact with the metal skin of the fuselage. Structural elements within the fuselage included loosely-spaced flat U-section formers throughout its length that worked in conjunction with the skin, which functioned aslongerons within the stress-resisting structure; in key areas, it was reinforced using fore-and-aft stringers.[4] The forward section of the fuselage had particularly strong frames in order to appropriately support thewing roots,undercarriagestruts and function as the attachment point for the anti-lift wirebracing. The latter feature was particularly crucial to the stability of the bracing of both the wings and the sizablefloats fitted.[5]
The aircraft was fitted with single-step floats; their structure comprised central longitudinalbulkheads that directly attached to the transverse frames.[6] Several of the longitudinal members were placed between the frames. They were almost entirely composed of duralumin, the centre section of the starboard float was made of steel to permit it to support the primary fuel tank.[6] As there was no room for a fuel tank within the fuselage, all of the aircraft's fuel was carried within the starboard float, which was 8 inches (20 cm) closer to the aircraft's centreline than the port float; this arrangement gave the aircraft a lowercentre of gravity as well as helping to offset engine talk.[7][8]
Largely due to a lack of available experimentation time during the aircraft's short development window, the use of an all-metal wing was discounted.[9] Instead, proven wooden construction was used for the wire-braced wings, which possessed sprucespars, spruce-plyribs and a smooth plywood covering.[7] They were built in two halves along a conventional twin-spar arrangement, albeit with a diagonal member between the wing tips and the fittings for thestreamlined bracing wires which stiffened the wing againsttorsion and reduced the likelihood of encounteringaeroelastic flutter.[10] Large radiators were present on the wings; positioned tightly against the wings, they were of a relatively low weight as to avoid incurring excessivewing loading.[11]
The engine was cooled via a somewhat unusual arrangement, usingradiators located on the wings in place of the Lamblin type radiators of the S.4; these radiators were made up ofcorrugated copper sheets and covered a large proportion of the wing surface.[7] Particular attention was paid to the oil system with the aim of minimising fractional losses in the propeller gearing and maximising the aircraft's speed potential.[12] As traditional arrangements were deemed to be insufficient, the oil was cooled via a series of corrugated steel radiators positioned on either side of the fuselage; further cooling of the gears themselves was achieved via several opening in the cowlings of the cylinder block.[7][13]
The forward bottom portion of the fuselage was reinforced usinglaminated duralumin to function as the engine bearer, comprising two primary box section bearers that were secured to cradles. One advantage of the scoop-formed engine mounting was a relatively high level of accessibility to the engine.[6] The engine itself was cleanly faired into the fuselage to maximise aerodynamic efficiency.[14]
The flight controls were of a conventional nature, lacking any implementation of variable gearing except for in the actuation of theailerons.[6] The aircraft was considered to be relatively easy to handle considering its relatively high top speed for the era.[6] The horizontal tail surfaces, which were made of wood, had their control cranks housed within the stern portion of the fuselage;[7] the cranks for theelevator were intentionally offset so they would sufficiently clear therudder post.[15]
A total of three aircraft were built, one with a direct drive 900 hp (670 kW)Napier Lion VIIA engine, and the other two with a geared 875 hp (652 kW) Napier Lion VIIB engine.[16]
The first aircraft performed itsmaiden flight on 7 June 1927. The S.5s came 1st and 2nd in the 1927 Schneider Trophy race held atVenice; the winning aircraft (Serial numberN220) was flown by Flight LieutenantSidney Webster at an average speed of 281.66 mph (453.29 km/h).[1][2]
One S.5,N221, crashed on 12 March 1928 during an attempt on the world air speed record, killing the pilotFlight LieutenantSamuel Kinkead, who had flown theGloster IV in the 1927 Schneider Trophy Race.[1][2]
Concern over the unreliability of the supercharged Lion powering theGloster VI led to the High Speed Flight entering one S.5 (N219, fitted with a geared Lion engine for the event) along with the twoS.6s for the 1929 Schneider contest. The S.5, flown by Flight Lieutenant D'Arcy Greig, finished third in 46 minutes and 15 seconds at a speed of 282.11 mph (454.01 km/h), behind the winning S.6 flown by Flying Officer H.Richard Waghorn and aMacchi M.52.[17]
Ray Hilborne of Leisure Sports designed and built a full-scale S.5 replica which flew for the first time on 28 August 1975. The replica, powered by aContinental IO-360, used an all-wood construction and incorporated modifications to the wing to lower the stalling speed, water rudders, a slightly wider cockpit and overall weight reduction to an all-up weight of just 1,500 lb (680 kg), less than half that of the S.5.[18]
In the song "Bill Hosie" byArchie Fisher, theprotagonist rebuilds a Supermarine S.5 that survived the 1927 Schneider Trophy contest. The aircraft, race, and trophy are referred to throughout the song.[citation needed]
Data fromSupermarine Aircraft since 1914,[19]National Advisory Committee for Aeronautics[20]
General characteristics
Performance
Related development
Related lists
