MB-2, NIEUPORT 28, SPAD 13, SOPWITH CAMEL, & LUSAC-ll
A sample Bristol arrived in New York on August 25, 1917, and immediately the Americans tried to redesign it to use the “United States Standard Aircraft Engine” as the Liberty 12 was called. Curtiss received a contract on November 3 to produce 1,000, later increased to 2,000, Liberty-powered Bristols designated USAO-1. Armament was to be two Marlin fixed and two Lewis flexible guns.
The first Curtiss Bristol with the Liberty began flight tests on March 5, 1918. While the British Bristol had done 119 mph weighing 2,779 pounds, the Curtiss version was supposed to do 138 mph at 2,937 pounds, but the actual weight came to 3,600 pounds and the engine was too much for the airframe.
It was also unsafe, for the second example crashed on May 5, another on June 10, and a third, on July 25. On July 20, 1918, the Curtiss-Bristol program was canceled after 27 aircraft had been completed, and the factory then concentrated on the S.E.5 program. Yet the Bristol’s RAF-15 airfoil section would become the wing pattern for most 1918 American fighters.
Curtiss did attempt to meet the contract by designing its own two-seater fighter with the Liberty engine and biplane wings so close together that the top wing was level with the laminated wood veneer fuselage top. This gave the observer a good fire field, but the pilot’s view down was poor. Known as the CB, for “Curtiss Battler,” the machine crashed during testing in 1918 and no technical details have been located.
Thomas-Morse received an order on November 12, 1917, to build two two-seater fighters around the 400-hp Liberty 12. The MB-l was a light high-wing monoplane braced by a wide strut, to be armed with two Marlin and two Lewis guns. The Ithaca, New York, firm towed it out to frozen Lake Cayuga late in January 1918. But the 900-pound direct-drive engine’s vibrations weakened the light airframe so much that the machine collapsed while being taxied out for flight trials.
The company replaced it with the MB-2 biplane, with a four-bladed propeller to absorb the power of a geared Liberty 12C cooled by radiators on the lower wings, and the same four guns. The difficult task of mating the big engine and light airframe delayed delivery until November 1918. The war’s end canceled this project and its half-finished sister ship, but Thomas-Morse would be more successful with its MB-3 single-seater.
Fighters with the AEF
Since the AEF came to France without planes, its future fighter pilots were trained on some 872 old-model Nieuports. The idea was that pilot proficiency would increase with the power of the planes flown. Anxious to begin fighting, the AEF decided to buy the Nieuport 28, which had already been rejected by the French in favor of the Spad.
Powered by a 150-hp Gnome with nine cylinders spinning around until the two-hour fuel supply ran out, this Nieuport had straight equal-span wings connected by an even pair of struts on each side, instead of the Vee struts of earlier Nieuports. Two Vickers guns were mounted on the left side ahead of the pilot.
The first 36 Nieuport 28s were turned over to the Americans in March 1918, but the lack of guns delayed their debut into combat until April. By the end of May, all four squadrons of the First Pursuit Group were at the front, and they continued to use Nieuports until Spads began arriving in July. The AEF had 297 of some 310 Nieuport 28s built, but the Nieuport’s reputation for wing failures led the Americans to quickly discard the type when the more robust Spads became available.
The first Spad 13 was ferried in to the First Pursuit Group on July 5 by Captain “Eddie” Rickenbacker (1890-1973). During the last four months of the war, he, Frank Luke, and other AEF pilots made the French fighter part of the American military tradition. Spad 13s were already being used by the Lafayette Escadrille that became the Army’s 103rd Aero Squadron, but continued operating with the French Army until August 1918, when it became part of the AEF’s new 3rd Pursuit Group.