Miloch
July 19th 19, 02:12 PM
https://en.wikipedia.org/wiki/Supermarine_S.6B
The Supermarine S.6B is a British racing seaplane developed by R.J. Mitchell for
the Supermarine company to take part in the Schneider Trophy competition of
1931. The S.6B marked the culmination of Mitchell's quest to "perfect the design
of the racing seaplane" and represented the cutting edge of aerodynamic
technology for the era.
The S.6B was last in a line of racing seaplanes to be developed by Supermarine,
followed on from the S.4, S.5 and the S.6. Despite these predecessors having
twice won the Schneider Trophy previously, the development of the S.6B was
troubled by wavering government support, being promised, withdrawn, and then
issued once again following a high-profile public campaign encouraged by Lord
Rothermere and a substantial donation by Lady Houston. Once government backing
had been secured, there was only nine months remaining until the race, thus
Mitchell decided to refine the existing S.6 rather than pursue a clean-sheet
design, thus the type's designation of S.6B.
The principal design differences between the S.6 and the S.6B were made in its
more powerful Rolls-Royce R engine and redesigned floats, providing much needed
additional cooling; minor aerodynamic refinements typically aimed at drag
reduction were also implemented. A pair of S.6Bs, serials S1595 and S1596, were
constructed for the competition. Flown by members of RAF High Speed Flight, the
type competed successfully, winning the Schneider Trophy for Britain. Shortly
after the race, S.6B S1596, flown by Flt Lt. George Stainforth, broke the world
air speed record, attaining a peak speed of 407.5 mph (655.67 km/h).
Supermarine did not build any successive racing aircraft during this era,
largely due to other commitments, including the development of a new fighter
aircraft at the request of the British Air Ministry, known as the Type 224.
Mitchell and his team's experience in designing high speed Schneider Trophy
floatplanes greatly contributing to the development of the later Supermarine
Spitfire, an iconic fighter aircraft flown in large numbers by the Royal Air
Force; it has been viewed as Britain's most successful interceptor of the Second
World War. Both the Spitfire and its Rolls-Royce Merlin engine drew directly
upon the S.6B and its Rolls-Royce R engine respectively.
Financing
Despite Prime Minister James Ramsay MacDonald's pledge that government support
would be provided for the next British race entrant immediately after Britain's
1929 victory, official funding was withdrawn less than two months later
following the Wall Street Crash; the official reason given for the withdrawal
that the previous two contests had collected sufficient data on high speed
flight, so further expenditure of public money was unwarranted. A further
rational given of the government's revised position was that that original
purpose in pioneering high speed seaplanes had been satisfied by this point. A
committee established by the Royal Aero Club, who were responsible for
organising the 1931 race and included representatives from both the aircraft and
aero engine industries, was formed to discuss the feasibility of a privately
funded entry, but concluded that not only would this be beyond their financial
reach, but that the lack of the highly skilled RAF pilots of the High-Speed
Flight would pose a severe problem.
The apparent discontinuation of involvement resulted in enormous public
disappointment: having won two successive races, a British victory in a third
race would secure the trophy outright. As ever active in aviation affairs, Lord
Rothermere's Daily Mail group of newspapers launched a public appeal for money
to support a British race entrant; in response, several thousand pounds were
raised. Lady Houston publicly pledged £100,000. The British government also
changed its position and announced its support for an entry in January 1931;
however, by this point, there were less than nine months left to design, produce
and prepare any race entrant. The RAF High Speed Flight was reformed while
Mitchell and Rolls-Royce set to work.
Redesign and refinement
Mitchell, recognising that he only had seven months to prepare an entry, knew
that there was not enough time left to viably design a whole new aircraft from
scratch. Instead, he refined the design of the existing Supermarine S.6; the new
variant being referred to as the Supermarine S.6B. According to aviation author
John D. Anderson Jr, Mitchell retained the majority of the S.6's design, his
efforts being principally focused on improving the prospective aircraft's heat
dissipation; speaking on a radio broadcast, he later referred to the S.6B as a
"flying radiator". Mitchell decided to make use of the aircraft's floats as an
additional radiator area; these were considerably larger than those of the S.6,
their design being supported by a series of wind tunnel tests performed at the
National Physical Laboratory, which was also an area in which government support
was helpful to the project. The floats were extended forward by some three feet
(0.9 m); while being larger and longer than their predecessor's counterparts,
they were streamlined and had a smaller frontal area.
One obvious means of improving the S.6's performance was by obtaining more power
from the R-Type engine. Engineers at Rolls-Royce's Derby facility had managed to
increase the available power of the engine by 400 hp (298 kW), enabling it to
now provide up to 2,300 hp (1,715 kW); however, this level of performance was
only guaranteed for a fairly small timeframe. To improve the engine performance,
the use of an exotic fuel mix was necessary, as well as the adoption of
Sodium-cooled valves. Anderson states that the improvements to the engine and
the floats were the only two major innovations of the S.6. Other modifications
to the airframe design were mostly limited to minor improvements and some
strengthening in order to cope with the increased weight of the aircraft. One
cutting-edge feature used in the aircraft's manufacture was the use of flush
riveting, a newer and more expensive form of riveting that had drag reduction
benefits. Drag reduction was an important priority of Mitchell's refinements,
this factor being greatly beneficial to any fast-moving aircraft.
Role
Experimental aircraft, Racing seaplane
Manufacturer
Supermarine
Designer
R.J. Mitchell
First flight
1931
Introduction
1931
Primary user
Royal Air Force
Number built
2
Developed from
Supermarine S.6
Although the British team faced no competitors, due to misfortunes and delays
suffered by other intending participants, the RAF High Speed Flight brought a
total of six Supermarine Schneider racers to Calshot Spit on Southampton Water
for training and practice. These aircraft were: S.5 serial number N219, second
at Venice in 1927, S.5 N220, winner at Venice in 1927, two S.6s with new engines
and redesignated as S.6As (N247 that won at Calshot in 1929 and S.6A N248,
disqualified at Calshot in 1929), and the newly built S.6Bs, S1595 and S1596.
For the competition itself, only the S.6Bs and S.6As were intended to
participate. The British plan for the Schneider contest was to have S1595 fly
the course alone and, if its speed was not high enough, or the aircraft
encountered mechanical failure, then the more-proven S.6A N248 would fly the
course. If both S1595 and N248 failed in their attempts, then N247, which was
planned to be held in reserve, would be used. The S.6B S1596 was then to attempt
the world air speed record. During practice, N247 was destroyed in a takeoff
accident, resulting in the death of the pilot, Lieut. G. L. Brinton, R.N.,
precluding any other plans with only the two S.6Bs and the sole surviving S.6A
prepared to conduct the final Schneider run.
On 13 September 1931, the winning Schneider flight was performed by S.6B S1595,
piloted by Flt. Lt. John Boothman, having attained a recorded top speed of
340.08 mph (547.19 km/h) and flown seven perfect laps of the triangular course
over the Solent, the strait between the Isle of Wight and the British mainland.
Seventeen days later, another historic flight was performed by S.6B S1596, flown
by Flt Lt. George Stainforth, having broken the world air speed record by
reaching a peak speed of 407.5 mph (655.67 km/h).
Legacy
The performance of the S.6B and its forerunners served as the foundations for
Mitchell to be recognised as a legendary designer of performance aircraft. The
S.6B has been hailed as giving the impetus to the development of both the
Supermarine Spitfire fighter aircraft and the Rolls-Royce Merlin engine that
powered it. Neither Mitchell nor Supermarine would produce further racing
aircraft for successive competitions as work on the development of a new fighter
aircraft at the British government's behest had taken precedence.
Only 18 days following the S.6B's Schneider triumph, the British Air Ministry
issued Specification F7/30, which called for a modern all-metal land-based
fighter aircraft and sought innovative solutions towards a major improvement in
British fighter aircraft; perhaps most significantly, the ministry specifically
invited Supermarine to participate. Accordingly, Mitchell's next endeavour after
the S.6B was to produce the company's submission to meet this specification,
which would be designated the Type 224. While the Type 224 would not meet with
government approval and ultimately be a disappointment, Supermarine's next
project would result in the development of the legendary Spitfire.
According to author Birch Matthews, the S.6B and Supermarine's racing lineage
had played an influence of the design of both the Type 224 and the Spitfire,
largely in terms of its aerodynamic cleanness and innovative heat dissipation,
there were substantial differences and fresh innovations being incorporated as
well. Furthermore, as observed by industrial consultant Philip H. Stevens, the
outstanding performance of the S.6B had drawn the attention of not only British
military officials and aircraft designers, but internationally as well,
influencing new fighter projects in, amongst other nations, both Nazi Germany
and the United States.
Specifications (S.6B)
General characteristics
Crew: 1
Length: 28 ft 10 in (8.79 m) including floats
25 ft 3 in (8 m) fuselage onlyWingspan: 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
Empty weight: 4,590 lb (2,082 kg)
Gross weight: 6,086 lb (2,761 kg)
Powerplant: × Rolls-Royce R V-12 liquid-cooled piston engine, 2,350 hp (1,750
kW) at 3,200 rpm
Propellers: 2-bladed fixed-pitch metal propeller
Performance
Maximum speed: 407.5 mph (656 km/h; 354 kn) (World speed record)
390 mph (340 kn; 630 km/h) normal, in level flightAlighting speed: 95 mph (83
kn; 153 km/h)
Wing loading: 42 lb/sq ft (210 kg/m2)
Power/mass: 0.386 hp/lb (0.635 kW/kg)
*
The Supermarine S.6B is a British racing seaplane developed by R.J. Mitchell for
the Supermarine company to take part in the Schneider Trophy competition of
1931. The S.6B marked the culmination of Mitchell's quest to "perfect the design
of the racing seaplane" and represented the cutting edge of aerodynamic
technology for the era.
The S.6B was last in a line of racing seaplanes to be developed by Supermarine,
followed on from the S.4, S.5 and the S.6. Despite these predecessors having
twice won the Schneider Trophy previously, the development of the S.6B was
troubled by wavering government support, being promised, withdrawn, and then
issued once again following a high-profile public campaign encouraged by Lord
Rothermere and a substantial donation by Lady Houston. Once government backing
had been secured, there was only nine months remaining until the race, thus
Mitchell decided to refine the existing S.6 rather than pursue a clean-sheet
design, thus the type's designation of S.6B.
The principal design differences between the S.6 and the S.6B were made in its
more powerful Rolls-Royce R engine and redesigned floats, providing much needed
additional cooling; minor aerodynamic refinements typically aimed at drag
reduction were also implemented. A pair of S.6Bs, serials S1595 and S1596, were
constructed for the competition. Flown by members of RAF High Speed Flight, the
type competed successfully, winning the Schneider Trophy for Britain. Shortly
after the race, S.6B S1596, flown by Flt Lt. George Stainforth, broke the world
air speed record, attaining a peak speed of 407.5 mph (655.67 km/h).
Supermarine did not build any successive racing aircraft during this era,
largely due to other commitments, including the development of a new fighter
aircraft at the request of the British Air Ministry, known as the Type 224.
Mitchell and his team's experience in designing high speed Schneider Trophy
floatplanes greatly contributing to the development of the later Supermarine
Spitfire, an iconic fighter aircraft flown in large numbers by the Royal Air
Force; it has been viewed as Britain's most successful interceptor of the Second
World War. Both the Spitfire and its Rolls-Royce Merlin engine drew directly
upon the S.6B and its Rolls-Royce R engine respectively.
Financing
Despite Prime Minister James Ramsay MacDonald's pledge that government support
would be provided for the next British race entrant immediately after Britain's
1929 victory, official funding was withdrawn less than two months later
following the Wall Street Crash; the official reason given for the withdrawal
that the previous two contests had collected sufficient data on high speed
flight, so further expenditure of public money was unwarranted. A further
rational given of the government's revised position was that that original
purpose in pioneering high speed seaplanes had been satisfied by this point. A
committee established by the Royal Aero Club, who were responsible for
organising the 1931 race and included representatives from both the aircraft and
aero engine industries, was formed to discuss the feasibility of a privately
funded entry, but concluded that not only would this be beyond their financial
reach, but that the lack of the highly skilled RAF pilots of the High-Speed
Flight would pose a severe problem.
The apparent discontinuation of involvement resulted in enormous public
disappointment: having won two successive races, a British victory in a third
race would secure the trophy outright. As ever active in aviation affairs, Lord
Rothermere's Daily Mail group of newspapers launched a public appeal for money
to support a British race entrant; in response, several thousand pounds were
raised. Lady Houston publicly pledged £100,000. The British government also
changed its position and announced its support for an entry in January 1931;
however, by this point, there were less than nine months left to design, produce
and prepare any race entrant. The RAF High Speed Flight was reformed while
Mitchell and Rolls-Royce set to work.
Redesign and refinement
Mitchell, recognising that he only had seven months to prepare an entry, knew
that there was not enough time left to viably design a whole new aircraft from
scratch. Instead, he refined the design of the existing Supermarine S.6; the new
variant being referred to as the Supermarine S.6B. According to aviation author
John D. Anderson Jr, Mitchell retained the majority of the S.6's design, his
efforts being principally focused on improving the prospective aircraft's heat
dissipation; speaking on a radio broadcast, he later referred to the S.6B as a
"flying radiator". Mitchell decided to make use of the aircraft's floats as an
additional radiator area; these were considerably larger than those of the S.6,
their design being supported by a series of wind tunnel tests performed at the
National Physical Laboratory, which was also an area in which government support
was helpful to the project. The floats were extended forward by some three feet
(0.9 m); while being larger and longer than their predecessor's counterparts,
they were streamlined and had a smaller frontal area.
One obvious means of improving the S.6's performance was by obtaining more power
from the R-Type engine. Engineers at Rolls-Royce's Derby facility had managed to
increase the available power of the engine by 400 hp (298 kW), enabling it to
now provide up to 2,300 hp (1,715 kW); however, this level of performance was
only guaranteed for a fairly small timeframe. To improve the engine performance,
the use of an exotic fuel mix was necessary, as well as the adoption of
Sodium-cooled valves. Anderson states that the improvements to the engine and
the floats were the only two major innovations of the S.6. Other modifications
to the airframe design were mostly limited to minor improvements and some
strengthening in order to cope with the increased weight of the aircraft. One
cutting-edge feature used in the aircraft's manufacture was the use of flush
riveting, a newer and more expensive form of riveting that had drag reduction
benefits. Drag reduction was an important priority of Mitchell's refinements,
this factor being greatly beneficial to any fast-moving aircraft.
Role
Experimental aircraft, Racing seaplane
Manufacturer
Supermarine
Designer
R.J. Mitchell
First flight
1931
Introduction
1931
Primary user
Royal Air Force
Number built
2
Developed from
Supermarine S.6
Although the British team faced no competitors, due to misfortunes and delays
suffered by other intending participants, the RAF High Speed Flight brought a
total of six Supermarine Schneider racers to Calshot Spit on Southampton Water
for training and practice. These aircraft were: S.5 serial number N219, second
at Venice in 1927, S.5 N220, winner at Venice in 1927, two S.6s with new engines
and redesignated as S.6As (N247 that won at Calshot in 1929 and S.6A N248,
disqualified at Calshot in 1929), and the newly built S.6Bs, S1595 and S1596.
For the competition itself, only the S.6Bs and S.6As were intended to
participate. The British plan for the Schneider contest was to have S1595 fly
the course alone and, if its speed was not high enough, or the aircraft
encountered mechanical failure, then the more-proven S.6A N248 would fly the
course. If both S1595 and N248 failed in their attempts, then N247, which was
planned to be held in reserve, would be used. The S.6B S1596 was then to attempt
the world air speed record. During practice, N247 was destroyed in a takeoff
accident, resulting in the death of the pilot, Lieut. G. L. Brinton, R.N.,
precluding any other plans with only the two S.6Bs and the sole surviving S.6A
prepared to conduct the final Schneider run.
On 13 September 1931, the winning Schneider flight was performed by S.6B S1595,
piloted by Flt. Lt. John Boothman, having attained a recorded top speed of
340.08 mph (547.19 km/h) and flown seven perfect laps of the triangular course
over the Solent, the strait between the Isle of Wight and the British mainland.
Seventeen days later, another historic flight was performed by S.6B S1596, flown
by Flt Lt. George Stainforth, having broken the world air speed record by
reaching a peak speed of 407.5 mph (655.67 km/h).
Legacy
The performance of the S.6B and its forerunners served as the foundations for
Mitchell to be recognised as a legendary designer of performance aircraft. The
S.6B has been hailed as giving the impetus to the development of both the
Supermarine Spitfire fighter aircraft and the Rolls-Royce Merlin engine that
powered it. Neither Mitchell nor Supermarine would produce further racing
aircraft for successive competitions as work on the development of a new fighter
aircraft at the British government's behest had taken precedence.
Only 18 days following the S.6B's Schneider triumph, the British Air Ministry
issued Specification F7/30, which called for a modern all-metal land-based
fighter aircraft and sought innovative solutions towards a major improvement in
British fighter aircraft; perhaps most significantly, the ministry specifically
invited Supermarine to participate. Accordingly, Mitchell's next endeavour after
the S.6B was to produce the company's submission to meet this specification,
which would be designated the Type 224. While the Type 224 would not meet with
government approval and ultimately be a disappointment, Supermarine's next
project would result in the development of the legendary Spitfire.
According to author Birch Matthews, the S.6B and Supermarine's racing lineage
had played an influence of the design of both the Type 224 and the Spitfire,
largely in terms of its aerodynamic cleanness and innovative heat dissipation,
there were substantial differences and fresh innovations being incorporated as
well. Furthermore, as observed by industrial consultant Philip H. Stevens, the
outstanding performance of the S.6B had drawn the attention of not only British
military officials and aircraft designers, but internationally as well,
influencing new fighter projects in, amongst other nations, both Nazi Germany
and the United States.
Specifications (S.6B)
General characteristics
Crew: 1
Length: 28 ft 10 in (8.79 m) including floats
25 ft 3 in (8 m) fuselage onlyWingspan: 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
Empty weight: 4,590 lb (2,082 kg)
Gross weight: 6,086 lb (2,761 kg)
Powerplant: × Rolls-Royce R V-12 liquid-cooled piston engine, 2,350 hp (1,750
kW) at 3,200 rpm
Propellers: 2-bladed fixed-pitch metal propeller
Performance
Maximum speed: 407.5 mph (656 km/h; 354 kn) (World speed record)
390 mph (340 kn; 630 km/h) normal, in level flightAlighting speed: 95 mph (83
kn; 153 km/h)
Wing loading: 42 lb/sq ft (210 kg/m2)
Power/mass: 0.386 hp/lb (0.635 kW/kg)
*