The idea behind the Sopwith Triplane (curiously, it does not seem to have had any official name or designation) was that a wing with a narrow chord would provide a correspondingly small change in the center of pressure at various angles of attack. That meant that the fuselage and tail, which balanced the airplane, could be shorter than they needed to be on an airplane with wider chord wings. In theory, the shorter the fuselage was, the quicker the maneuverability would be in pitch and yaw. Dividing the wing area into three parts also allowed the wings to be constructed with a shorter span, which increased the rate of roll. Smith also designed it with ailerons on all three wings to increase maneuverability.

Subscribe Today

• Did you enjoy our article?
• Read more in Aviation History magazine
• Subscribe online and save nearly 40%!!!
 

Another benefit of the triplane format was an improvement in climb rate and ceiling. Since the wing area was divided by three, the wings could be built with a narrower chord in relation to their span. Such high-aspect-ratio wings produce a very efficient ratio of lift to drag. Anyone who has ever seen an albatross or a sailplane in flight can testify to the aerodynamic efficiency of long, narrow wings. As a bonus, the narrow-chord wings above and below the pilot interfered less with his view than the wider wings of a biplane or monoplane. Moreover, the middle wing was mounted in line with the pilot’s eyes, so that he could easily see around it.

To further enhance the triplane’s maneuverability, Smith carefully grouped the heaviest weights-pilot, fuel, armament and engine-near the center of gravity. To a large extent, that was made possible by the use of a compact, aircooled rotary engine. Both rotary engines and the related radial aircraft engines were constructed with their cylinders arranged around a common axis. Unlike the radial engines, which were rigidly attached to the airframe and drove the propeller by means of a revolving crankshaft, on the earlier rotary engines the propeller was bolted directly to the crankcase, while the engine itself revolved around a crankshaft attached to the airframe. The entire engine acted, in effect, like a giant flywheel.

The Sopwith Triplane was designed and built in less than three months. Yet, when it was first flown on May 30, 1916, test pilot Harry Hawker was so pleased with the prototype that he looped it three minutes after the first takeoff. Two weeks later, the same prototype, N500, was dispatched to a front-line squadron for evaluation and flew its first combat mission 15 minutes after arrival.

The appearance of the Sopwith Triplane was nothing if not startling; one observer likened its appearance in flight to an intoxicated flight of stairs. The impression from inside the cockpit was summed up by pilot Herbert Thompson, who wrote in his log book: The best machine I have ever flown. Thoroughly in love with it. Much later, Sir Herbert Thompson added, After fifty years I still am.

About the only reservation service pilots had about the new Sopwith was that its endurance, about 1 3/4 hours, was slightly less than ideal. Powered by a 130-hp Clerget rotary engine, the Sopwith Triplane carried a single synchronized .303-caliber Vickers machine gun. Its top speed of 117 mph was reasonably good for its day, but its rate of climb, 5,000 feet in 4 1/2 minutes, was considered phenomenal. It also had a ceiling of more than 20,000 feet, higher than that of most German planes, which gave the British fighter a significant tactical benefit — the ability to attack with a height advantage. In the event that a Sopwith Triplane was attacked, the pilot could simply execute a climbing turn that no German fighter could follow.

P>The first fully equipped squadrons of Sopwith Triplanes began to make their appearance at the front early in 1917, a period when the fortunes of British airmen were at their lowest ebb. So heavy were RFC losses that April 1917 became known in that service as Bloody April. The triplanes were not operated by the Royal Flying Corps, however, but by the Royal Naval Air Service (RNAS). Although there were never more than six squadrons of Sopwith Triplanes on the Western Front, their impact greatly exceeded their numbers.

Help HistoryNet by bookmarking to