The Sopwith Admiralty 9700 1 1/2 Strutter:
Historical Notes:
When the Sopwith Aviation Company designed their two seat biplane, they were still contractors for the Admiralty. Therefore, the machine received the designation as Sopwith Type 9700. When the RFC received the machine it became known to them as the Sopwith Two-Seater. However, to the crews who flew it, it became known as the 1 ½ Strutter. The origin of the this name is uncertain, but appears to have much to do with the outer struts of the central bracing on the wing, which were about half the size of the interplane struts. Hence the unique name.The 1 ½ Strutter has the distinction of being the first Sopwith aircraft to have the trademark rudder and tailplane surface, and it was also the first machine designed with an interrupter gear for a forward firing machine gun. The layout of the aircraft was of standard arrangement, with a wire-braced box girder fuselage and plywood around the cockpit. The pilot was in front, directly under the wing, with the observer in back. In between the two was the main fuel tank. The wings had twin spars and usually a large cut out above the pilot's position. The tailplane was unique as well, having an adjustable incidence controlled by a wheel in the cockpit. The pilot could adjust this according to the load carried. One other unusual feature was the square air brakes. These were located on the trailing part of the lower wings just next to the fuselage and when used extended upward. However, these were rarely used, nor did they resemble modern day flaps.
The 1 ½ Strutter was an easy plane to fly, although the controls resisted attitude changes, especially dives. Initially equipped with a 110hp Clerget rotary, later models had 130hp engines. Rotaries had a unique way of telling a pilot if his fuel adjustments were incorrect: Black smoke meant too much fuel when starting, while white smoke meant too much castor oil. Furthermore, because rotaries partly relied on whirling air and airspeed for cooling, pilots were not to run the engines at full throttle on the ground until taking off, since they would quickly overheat. The tailplane wheel meant that the Strutter could be trimmed, making it easy to fly level.
Armament typically consisted of a single Vickers machine gun synchronized to fire forward through the airscrew, using a variety of interrupter gears, such as the Sopwith-Kauper and Scarff- Dibovski. The former was widely used, but tended to slow the rate of fire. Rear armament was usually a single Lewis gun. Early mounts limited the use of this weapon, but another design by Warrant Officer F.W. Scarff allowed for rapid flexibility of the weapon. This became known as the "Scarff Mount" and is often visible in photos of Allied two-seat aircraft. In many ways it was the forerunner of the rotating turret of WW II fame.
Few realize that unlike later years, many design concepts, both in aircraft and the accouterments used with them, were designed by active pilots seeking to gain the winning edge in the air. Machine gun mounts and drums, interrupter gears, engines, even the aircraft themselves, were often the products of combat pilots putting their experience to work. In many ways, early combat aviation was a true art.
The Admiralty's Royal Naval Air Serivce (RNAS) was the first to use the 1 ½ Stutter, mostly for minor bombing missions against airship sheds in northern Germany. But, when the RFC was preparing to support the July 1916 Somme Offensive they found they were woefully short of aircraft. The Admiralty offered a number of their 1 ½ Strutters to the RFC to fill out their ranks. While some sources site this as an "unselfish act" by the Admiralty, it is very possible that the Admiralty was looking toward the adoption of a new aircraft to give them more influence in the air war in France, that plane being the Sopwith Pup.
1 ½ Strutters were also very useful as test aircraft, and experiments with flotation gear, as a carrier plane, and as a catapulted machine from cruisers were conducted by the Admiralty. The 1 ½ Strutter's primary influence in combat was the double-armament arrangement. Its speed helped as well, although it was not an overly fast plane. However, compared to many aircraft it faced in late 1916, the Strutter was a decent performer. A number of Strutters performed missions in other theaters, including anti-submarine patrols, and was built under license by other nations, including France. Belgium, Rumania and Russia also used Strutters supplied to them. Even the United States used many as trainers by 1918.
Basic performance statistics: Sopwith Admiralty 9700 1 ½ Strutter two-seat
Engine: 130hp Clerget
Weight: empty 1,305 lbs; loaded: 2,150 lbs
Maximum speed: 100 mph at 6,500 feet; 97.5 mph at 10,000 feet
Climb rate: to 6,500 feet.... 9 min 10 sec.; to 10,000 feet... 17 min 50 sec.
Service ceiling: 15,500 feet
Flight endurance: 3.75 hours
Basic Specifications of Sopwith 1 ½ Strutter:
Manufacturer: Sopwith Aviation Co., Ltd., Canbury Park Road, Kingston-on-Thames
Dimensions: Span 33 ft, 6 in; Length 25 ft, 3 in; Height: 10 ft, 3 in
Areas: Wings 346 sq ft
Fuel: 40 gallons; 9.5 gallons of oil.
Armament: one Vickers machine gun synchronized to fire through the airscrew; one Lewis gun for observer.
Primary sources: "French Aircraft of the First World War," Davilla and Soltan; "Jane's Fighting Aircraft of World War I, 1919 (1990 reprint); "British Aeroplanes, 1914-1918," J.M. Bruce; "German Aircraft of the First World War," Gray and Thetford; "German Air Power in World War I," Morrow; "Aircraft vs Aircraft," Franks; "Who Downed the Aces in WWI?" Franks; "Aircraft Camouflage and Markings 1907-1954," Robertson et al; "Military Small Arms of the 20th Century," Hogg and Weeks.
Fighting and winning in the Sopwith 1 ½ Strutter:
The 1 ½ Strutter is a good aircraft for late 1916. It has the advantage of a forward firing machine gun and is a better performer than the DH-2. In this respect, the Strutter can operate in a dual role, providing reconnaissance work and intercepting enemy machines, especially two- seaters. In team games, one way to use the Strutter is to let the escorts attack enemy scouts, while using the Strutters to engage enemy recon. Furthermore, the Strutter is fast enough to make a run away from enemy scouts if it is positioned correctly. Once past them, they will be hard pressed to catch it.Since the Strutter is a decent performer, gain as much altitude as possible. Second, if using a setup which brings clouds into the picture, prepare to dodge in and out of the clouds. Finally, good flying when under attack can succeed, especially since it is more nimble than such machines as the B.E.2c.
Use altitude and position yourself at right angles to enemy attack. Force him to attack at right angles. If the enemy pilot is unskilled, he will often attempt to turn back quickly for another attack using a snap turn. As a result, he will continue to lose altitude. When an enemy makes his attack and passes you, turn to follow him, keeping the distance as tight as possible and using the front gun to damage him. He will take evasive maneuvers causing him to lose more altitude. Furthermore, this will prevent him from taking distant shots at you even though you have an altitude edge. Use the rear gun only if you cannot keep an enemy from getting behind you, since its effectiveness is limited.
