The Curtiss O-13 Falcon was the designation given to a small number of O-1 and O-11 Falcon two-seat observation aircraft that were given the Curtiss V-1570 Conqueror engine. Some were produced as racers while others were used to test the Conqueror engine in a standard observation aircraft.
The XO-13 was produced by fitting a 600hp Curtiss V-1570 Conqueror engine in the eighth O-1. The engine was uprated to 730hp and the aircraft was entered in the Liberty Engine Builders Trophy event at the 1927 National Air Races. The XO-13 came second in the closed-course race, with a speed of 164mph.
The winner of the same race was the XO-13A. This aircraft had the same engine, rated at 720hp, but also had wind surface radiators installed (as used on the Curtiss PW-8). These reduced drag although were too vulnerable to damage for a combat aircraft. The XO-13A achieved a top speed of 170.5mph on the closed course.
The O-13B was the designation given to a single O-1C that was given a standard Curtiss V-1570-1 Conqueror engine. It was produced to test the new engine in a normal observation aircraft rather than in a specially modified racer.
YO-13C was the designation given to three O-1Es that were given 600hp V-1570 Conqueror engines. The designation was later changed to O-13C. The sole YO-13D also became a O-13C for a short period when its supercharged engine was removed.
The YO-13D had a supercharged Curtiss SV-1570 Conqueror engine and a modified radiator. It was produced from a standard O-11, and after a period of tests was turned into a standard O-13C after an un-supercharged Conqueror engine was installed. This was later replaced with a V-1150-5 engine, turning the aircraft into a O-1B.
Engine: Curtiss V-1570 Conqueror
Gross weight: 4,542lb
Max speed: 156.2mph
Service ceiling: 19,700ft