By the last year of World War I, the major combatants had made significant contributions to the aeronautical state of the art.
America created the Liberty engine. Germany produced the advanced Fokker D.VII biplane fighter. France gave the Allies the sturdy and fast SPAD XIII. And England, after a bit of a rough start, produced one of the finest fighters of the war, the S.E. 5A.
The years of aerial combat had distilled early fighter rationale down to a formula that often included a short-coupled biplane with one or two forward-firing machine guns. But from there, the variations flourished. If the French SPAD series lacked appreciable dihedral, the scrappy S.E. 5A was characterized by the upward sweep of its wings.
Where Fokker used welded steel tubing for the D.VII fuselage, the S.E. 5A relied on the standard wood-and-fabric structure of the day.
The S.E. 5A gained a reputation as a stable gun platform, attributable to its marked dihedral and forward stagger of the wings.
And it had enviable speed. The S.E. 5A joined the Sopwith Camel and other Allied fighters in a successful effort to re-establish Allied air superiority from mid-1917 to the end of the war in November 1918. Depending on the source, the S.E. 5A is credited with being as fast as 132 miles per hour at 6,500′; some sources say 138 mph. By comparison, the Fokker D.VII topped out at about 117 or 124 mph, based on its powerplant selection, and the French SPAD XIII could squeeze 131 miles per hour from its Hispano-Suiza V-8.
But the S.E. 5’s road to glory was bumpy. The early Hispano-Suiza 150-horsepower liquid-cooled V-8 engine was replaced with a geared 200-horsepower model from Hispano-Suiza that proved less reliable than desired for a combat aircraft, and there are stories of propellers and even gearboxes departing the airframe in flight.
A British license-built high compression variant of the Hispano-Suiza direct-drive version of the engine, known as the Wolseley Viper, subsequently proved the right combination to make the S.E. 5A a war winner.
The S.E. 5’s two-gun armament consisted of a .30-caliber Lewis machine gun mounted atop the upper wing and a Vickers gun in the fuselage. The Lewis used an ingenious Foster mount that enabled the weapon to be brought back from the wing, pointing upward nearly vertical. The gun could be fired in this position, and it was easier to reload when brought back in this way.
The S.E. 5A design was born at the Royal Aircraft Factory at Farnborough. A team led by Henry Philip Folland crafted the boxy, yet not unappealing, design.
First flying in November 1916, the S.E. 5 entered service after a short period of development, in March 1917. But engine problems resulted in excess airframes on hand until the December 1917 mating of the Wolseley Viper to the S.E. 5A meant the design could realize its potential in 1918.
Inevitably, comparisons were drawn between the S.E. 5A and its main British contemporary, the Sopwith Camel. If the Camel was a masterfully maneuverable fighter in the hands of an expert pilot, the S.E. 5A was a safer mount for the flier of average experience.
Nearing the end of World War I, some S.E. 5As were fitted with bomb racks beneath the lower wing enabling four 25-pound bombs to be carried for infantry support sorties.
American airframe designs were still behind their European counterparts during World War I, and a contract was negotiated for Curtiss to mass-produce the S.E. 5A in America. The end of the war in November 1918 halted production, but 57 British S.E. 5A airframes had already been assembled by Curtiss, and the Air Service put these to use.
In 1922 and 1923, the Eberhart Steel Products Co. rebuilt 50 of the Air Service’s S.E. 5As, installing Wright-Hispano engines and skinning the fuselages in plywood. Thereafter, these modified fighters were designated S.E. 5E, and served as trainers for fighter pilots in the U.S.
The National Advisory Committee for Aeronautics borrowed one of the Air Service’s S.E. 5As beginning in 1922 for several years of aeronautical research in an era when many aeronautical concepts were still being baselined to give designers and engineers a fundamental set of parameters and data on which to base future developments.
The S.E. 5 biplane was looped, rolled, put in spins, given right and left wingovers, plus slips and skids.
The NACA’s three-axis accelerometer, a technical marvel of the day, measured loads on the aircraft. Testers found these to be nominally the same as loads earlier measured on a JN-4H Jenny trainer.
“It is noticeable that the S.E. 5A rolls smoothly and easily whereas the JN4h (sic) must be forced through a roll with a very high initial speed,” the report noted.
Motion picture pilot Frank Tallman had a lifelong affinity for the airplanes of World War I. The Tallmantz collection of vintage aircraft included an airworthy S.E. 5E Eberhart modification.
In his book “Flying the Old Planes,” Tallman described a takeoff in the S.E. 5E, with the tail coming up to level almost immediately after applying throttle for takeoff power. He said the slow-turning big wooden propeller, moving at about 1500 rpm for takeoff, did not produce any appreciable torque. The biplane left the ground in less than 250′, and climbed at between 75 and 80 mph with a rate of climb nearly 900 feet per minute.
The Tallmantz S.E. 5 was sold several times, migrating to England and then returning to America as part of the collection at the U.S. Army Aviation Museum at Fort Rucker, Alabama.