https://en.wikipedia.org/wiki/Sopwith_Dolphin
The Sopwith 5F.1 Dolphin was a British fighter aircraft manufactured by the
Sopwith Aviation Company. It was used by the Royal Flying Corps and its
successor, the Royal Air Force, during the First World War. The Dolphin entered
service on the Western Front in early 1918 and proved to be a formidable
fighter. The aircraft was not retained in the postwar inventory, however, and
was retired shortly after the war.
In early 1917, Sopwith's chief engineer Herbert Smith began designing a new
fighter (internal Sopwith designation 5F.1) powered by the geared 200 hp
Hispano-Suiza 8B. The resulting Dolphin was a two-bay, single-seat biplane. The
upper wings were attached to an open steel cabane frame above the cockpit. To
maintain the correct centre of gravity, the lower wings were positioned 13
wing stagger. The pilot sat with his head raised through the frame, where he had
an excellent field of view. This configuration sometimes caused difficulty for
novice pilots, who found it difficult to keep the aircraft pointed at the
horizon because the nose was not visible from the cockpit. The cockpit was
nevertheless warm and comfortable, in part because pipes ran alongside the
cockpit walls to the two side-mounted radiator blocks. Shutters in front of each
radiator core allowed control of engine temperature.
Role
Fighter
Manufacturer
Sopwith Aviation Company
Designer
Herbert Smith
First flight
23 May 1917
Introduction
February 1918
Primary users
Royal Flying Corps
Royal Air Force
Number built
2,072
The Dolphin Mk I became operational with Nos. 19 and 79 Squadrons in February
by several incidents in which British and Belgian pilots attacked the new
aircraft, mistaking it for a German type. For the next few weeks, Dolphin pilots
accordingly exercised caution near other Allied aircraft.
serious injury to the head and neck in the event of a crash. Early aircraft were
often fitted with improvised crash pylons consisting of steel tubes over the
cockpit to protect the pilot's head. Operational usage eventually showed that
fears of pilot injury from overturning were largely unfounded. Crash pylons
thereafter disappeared from front line aircraft, though they were often retained
on training aircraft. Night-flying Dolphins of No. 141 Squadron, a Home Defence
unit, had metal loops fitted above the inner set of interplane struts.
Despite early problems, the Dolphin eventually proved successful and generally
popular with pilots. The aircraft was fast, maneuverable, and easy to fly,
though a sharp stall was noted. When functioning properly, the Hispano-Suiza
afforded the Dolphin excellent performance at high altitude. Accordingly, the
Dolphin was often deployed against German reconnaissance aircraft such as the
Rumpler C.VII, which routinely operated at altitudes above 20,000 ft. No. 87
Squadron explored the use of equipment to supply pilots with oxygen at high
altitude, but the experiment was abandoned after trials showed that the oxygen
tanks exploded when struck by gunfire.
The scarcity and unreliability of the French-built Hispano-Suiza 8B engine
proved to be the most serious problem in the deployment and use of the Dolphin.
Use of insufficiently hardened metal in the pinion gears led to numerous
failures of the reduction gearing, particularly in engines built by the French
firm Brasier. The engine also suffered persistent lubrication problems. Limited
production capacity for the Hispano-Suiza engine, and the priority afforded to
French aircraft like the SPAD S.XIII slowed Dolphin deliveries. Availability of
the Hispano-Suiza improved in early 1918 as the French firm Emile Mayen began
deliveries on an order placed by the British Admiralty.
The official armament of the Dolphin was two fixed, synchronized Vickers machine
guns and two Lewis guns mounted on the forward cabane crossbar, firing at an
upward angle to avoid the propeller disc. The mounting provided three positions
in elevation and limited sideways movement. In service, however, the Lewis guns
proved unpopular, as they were difficult to aim and tended to swing into the
pilot's face. Pilots also feared that the gun butts would inflict serious head
injuries in the event of a crash. Most pilots therefore discarded the Lewis
guns, though a minority retained one or both guns specifically for attacking
high altitude reconnaissance aircraft from below.
Specifications (Dolphin Mk I)
General characteristics
Crew: 1
Length: 6.78 m (22 ft 3 in)
Wingspan: 9.91 m (32 ft 6 in)
Height: 2.59 m (8 ft 6 in)
Empty weight: 641 kg (1,410 lb)
Max. takeoff weight: 890 kg (1,959 lb)
Performance
Maximum speed: 211 km/h (131 mph) at sea level
Range: 315 km (195 mi)
Service ceiling: 6,100 m (20,000 ft)
Rate of climb: 12 min 5 sec to 3,048 m (10,000 ft)
Power/mass: 0.232 kW/kg (0.102 hp/lb)
Armament
Up to four 25 lb bombs
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