thomasmorse

Via www.joebaugher.com: "The XP-13 was the last fighter built by the Thomas-Morse Aircraft Corporation of Ithaca, NY. The XP-13 (named "Viper" by the company) was created for the new 600 hp Curtiss H-1640-1 Chieftain twelve-cylinder 2-row air-cooled engine. Thomas-Morse's experience with the manufacture of all-metal aircraft stood them in good stead in the design of the Viper. The fuselage had an all-metal structure covered by a corrugated aluminum-sheet skin. The wing was of wooden construction with fabric covering, but the ailerons were made of corrugated metal sheet. Tail surfaces were of metal and fabric, but the control surfaces were covered with corrugated sheet metal. The Viper was delivered to the USAAC for evaluation at Wright Field in June 1929 as "P-559". The aircraft was tested then purchased by the Army and designated XP-13 with S/N 29-453. Performance was satisfactory, but the Curtiss-built H-1640-1 Chieftain engine suffered insurmountable cooling problems. The XP-13 had an empty weight of 2262 lbs and a gross weight of 3256 lbs. The maximum speed was 172.5 mph at sea level, 169.9 mph at 5000 feet. The XP-13 could climb to 5000 feet in 3 minutes, and the service ceiling was 20,800 feet. The XP-13 was not fitted with any armament. Abandoning the Chieftain engine, the XP-13 prototype was then fitted with a 525 hp Pratt and Whitney SR-1340-C radial enclosed in a NACA cowling along with a revised fin and rudder in September 1930. The designation was changed to XP-13A. The change to a new engine resulted in even better performance. The XP-13A had an empty weight of 2224 lbs and a gross weight of 3194 lbs. Maximum speed was 188.5 mph at 5000 feet. The XP-13A could climb to 5000 feet in 3.5 minutes, and service ceiling was 24,150 feet. A USAAC performance report of 1930 described the XP-13A as having a "comfortable feel" in all aerobatics and that it "makes a wonderfully smooth slow roll". However, by then the opportunity had passed and the Army never ordered the aircraft into production. The Viper prototype caught fire during its last test flight and was destroyed in the resulting crash. The failure of the XP-13 to win a contract was catastrophic for Thomas-Morse, and in August 1929, the Thomas-Morse company was taken over by the Consolidated Aircraft Company of Buffalo, New York. The Thomas-Morse company disappeared as a separate entity shortly thereafter."

A regular S4-C.

Regular S4-C's.