The Sopwith Pup is a British single-seater biplane fighter aircraft built by the Sopwith Aviation Company. It entered service with the Royal Naval Air Service and the Royal Flying Corps in the autumn of 1916. With pleasant flying characteristics and good manoeuvrability, the aircraft proved very successful. The Pup was eventually outclassed by newer German fighters, but it was not completely replaced on the Western Front until the end of 1917. The remaining Pups were relegated to Home Defence and training units. The Pup's docile flying characteristics also made it ideal for use in aircraft carrier deck landing and takeoff experiments and training.
Design and development
In 1915, Sopwith produced a personal aircraft for the company's test pilot Harry Hawker, a single-seat, tractor biplane powered by a seven-cylinder 50 hp (37 kW) Gnome rotary engine which was known as "Hawker's Runabout". Another four similar aircraft have been tentatively identified as Sopwith Sparrows. Sopwith next developed a larger and more powerful aircraft as a fighter that was heavily influenced by this design, although controlled laterally with ailerons rather than by wing warping.

The resulting aircraft was a single-bay, single-seat biplane with a fabric-covered wooden framework and staggered equal-span wings. The cross-axle type main landing gear was supported by V-struts attached to the lower fuselage longerons. The prototype and most production Pups were powered by the 80 hp (60 kW) Le Rhône 9C rotary engine. The armament was a single 0.303 in (7.7 mm) Vickers machine gun synchronized with the Sopwith-Kauper synchronizer.

A prototype was completed in February 1916 and sent to Upavon for testing in late March. The Royal Naval Air Service (RNAS) quickly ordered two more prototypes, then placed a production order. Sopwith was heavily engaged in the production of the Sopwith 1½ Strutter, and produced only a small number of Pups for the RNAS. Deliveries commenced in August 1916.

The Royal Flying Corps (RFC) also placed large orders for Pups. The RFC orders were undertaken by sub-contractors Standard Motor Co. and Whitehead Aircraft. Deliveries did not commence until the beginning of 1917. 1,796 Pups were built, including 96 by Sopwith, 850 by Standard Motor Co., 820 by Whitehead Aircraft, and 30 by William Beardmore & Co.
Operational history
In May 1916, the RNAS received its first Pups for operational trials with "A" Naval Squadron. The first Pups reached the Western Front in October 1916 with No. 8 Squadron RNAS, and proved successful, with the squadron's Pups claiming 20 enemy machines destroyed in operations over the Somme battlefield by the end of the year. The first RFC Squadron to re-equip with the Pup was No. 54 Squadron, which arrived in France in December. The Pup quickly proved its superiority over the early Fokker, Halberstadt and Albatros biplanes. After encountering the Pup in combat, Manfred von Richthofen said, "We saw at once that the enemy aeroplane was superior to ours".

The Pup's light weight and generous wing area gave it a good rate of climb. Agility was enhanced by having ailerons on both wings. The Pup had half the horsepower and armament of the German Albatros D.III, but was much more manoeuvrable, especially over 15,000 ft (4,600 m) due to its low wing loading. Ace James McCudden stated that "When it came to manoeuvring, the Sopwith [Pup] would turn twice to an Albatros' once ... it was a remarkably fine machine for general all-round flying. It was so extremely light and well surfaced that after a little practice one could almost land it on a tennis court." However, the Pup was also longitudinally unstable.

At the peak of its operational deployment, the Pup equipped only four RNAS squadrons (Nos. 3, 4, 8 and 9), and three RFC squadrons (Nos. 54, 46 and 66). By the spring of 1917, the Pup had been outclassed by the newest German fighters. The RNAS replaced their Pups, first with Sopwith Triplanes, and then with Sopwith Camels. The RFC soldiered on with Pups, despite increasing casualties, until it was possible to replace them with Camels in December 1917.
Home Defence duties
The raids on London by Gotha bombers in mid-1917 caused far more damage and casualties than the earlier airship raids. The ineffective response by British interceptor units had serious political repercussions. In response, No. 66 Squadron was withdrawn to Calais for a short period, and No. 46 was transferred for several weeks to Sutton's Farm airfield near London. Two new Pup squadrons were formed specifically for Home Defence duties, No. 112 in July, and No. 61 in August.

The first Pups delivered to Home Defence units utilised the 80 hp (60 kW) Le Rhône, but subsequent Home Defence Pups standardised on the more powerful 100 hp (75 kW) Gnome Monosoupape, which provided an improved rate of climb. These aircraft were distinguishable by the addition of vents in the cowling face. In 1917, the Admiralty acquired the Sopwith Pup.
Shipboard use
Sopwith Pups were also used in many pioneering carrier experiments. On 2 August 1917, a Pup flown by Sqn Cdr Edwin Harris Dunning became the first aircraft to land aboard a moving ship, HMS Furious. Dunning was killed on his third landing when the Pup fell over the side of the ship. The Pup began operations on the carriers in early 1917; the first aircraft were fitted with skid undercarriages in place of the standard landing gear. Landings utilised a system of deck wires to "trap" the aircraft. Later versions reverted to the normal undercarriage. Pups were used as ship-based fighters on three carriers: HMS Campania, Furious and Manxman. Some other Pups were deployed to cruisers and battleships where they were launched from platforms attached to gun turrets. A Pup flown from a platform on the cruiser HMS Yarmouth shot down the German Zeppelin L 23 off the Danish coast on 21 August 1917.

The U.S. Navy also employed the Sopwith Pup with Australian pilot Edgar Percival testing the use of carrier-borne fighters. In 1926, Percival flew a Pup from a platform on turret "B" on the battleship USS Idaho at Guantánamo Bay, Cuba prior to the ship undergoing a major refit that added catapults on the stern.
Training duties
The Pup saw extensive use as a trainer. Student pilots completing basic flight training in the Avro 504k often graduated to the Pup as advanced trainers. The Pup was also used in Fighting School units for instruction in combat techniques. Many training Pups were reserved by senior officers and instructors as their runabouts while a few survived in France as personal or squadron 'hacks' long after the type had been withdrawn from combat.
Variants
Sopwith Admiralty Type 9901
Admiralty designation.
Sopwith Pup (official designation Sopwith Scout)
Single-seat scout (fighter) biplane; 1,770 built.



















Sopwith Dove
Two-seat civilian biplane; ten built.








Alcock Scout
Aircraft built partially from the remains of a crashed Pup and other aircraft; one built.

Beardmore W.B.III
Shipboard variant designed to fold into smallest possible volume; 100 built.
Design and development
Compared to the Sopwith Pup on which it was based, the WB.III featured a redesigned wing cellule with no stagger and an extra set of struts inboard, facilitating folding for stowage; a modified fuselage that carried emergency floatation gear; and main undercarriage that could be folded for stowage on the WB.IIIF. Later examples, designated WB.IIID, could jettison their undercarriage for safer water landings.

As many as one hundred were built, with small numbers deployed on various Royal Navy warships including the aircraft carriers HMS Furious and HMS Argus; and seaplane tenders HMS Nairana and HMS Pegasus. Performance was inferior that of to the Pup and it was largely superseded by the Sopwith 2F1 Ships Camel.






Specifications (80 hp Le Rhône)
Crew: 1
Length: 19 ft 3.75 in (5.8865 m)
Wingspan: 26 ft 6 in (8.08 m)
Height: 9 ft 5 in (2.87 m)
Wing area: 254 sq ft (23.6 m2)
Empty weight: 787 lb (357 kg)
Gross weight: 1,225 lb (556 kg)
Powerplant: 1 × Le Rhône 9C 9-cylinder air-cooled rotary piston engine, 80 hp (60 kW)
Propellers: 2-bladed wooden fixed-pitch propeller
Performance
Maximum speed: 112 mph (180 km/h, 97 kn)
Range: 337 mi (542 km, 293 nmi)
Endurance: 3 hours
Service ceiling: 17,500 ft (5,300 m)
Time to altitude:

10,000 ft (3,048 m) in 14 minutes
16,100 ft (4,907 m) in 35 minutes

Wing loading: 4.8 lb/sq ft (23 kg/m2)
Power/mass: 0.0654 hp/lb (0.1075 kW/kg)
Armament
Guns: 1 × .303 in (7.7 mm) Vickers machine gun fired forward through the propeller by means of a Sopwith-Kauper gun synchronizer
(text from Wikki)