The Curtiss CR was a racing aircraft designed for the United States Navy in 1921 by Curtiss.
It was a conventional single-seat biplane with a monocoque fuselage and staggered single-bay wings of equal span braced with N-struts.
Two essentially similar landplane versions were built as the CR-1 and CR-2, which were both eventually converted to seaplanes as the CR-3 in 1923 and CR-4 in 1924.
A refined version was developed for the US Army Air Service under the designation R-6.
These latter two aircraft featured refined aerodynamics included surface-mounted radiators.
The Curtiss CRs enjoyed successful racing careers.
Their first major win was at the 1921 Pulitzer Trophy race, where piloted by Bert Acosta the CR-1 took first place with an average speed of 176.75 mph (283.49 km/h), nearly two minutes ahead of its closest rival.
The following year, this aircraft was modified and redesignated CR-2 and joined in the Pulitzer race by a second aircraft built to the same new standard, plus two R-6s flown by Army pilots.
These Curtiss aircraft took first through fourth place, the two R-6s followed by the two CR-2s.
The race was won by Lt. Russell Maughan with an average speed of 205.856 mph (330.172 km/h) with Lt. Lester Maitland in second place (198.850 mph/318.936 km/h).
Maughan’s effort incidentally broke every closed-circuit airspeed record up to 124 mi (200 km).
The CR-2s took third and fourth places piloted by Lt Harold Brow (average speed 193.695 mph/310.667 km/h) and Lt JG AL Williams (average speed 187.996 mph/301.527 km/h).
The Army built upon this success with the R-6s by using the aircraft to break the world airspeed record before 1922 was over, Gen Billy Mitchell flying one to 224.28 mph (359.72 km/h) on 18 October.
In March the following year, an R-6 flown by Lt. Maughan lifted the record to 236.587 mph (380.74 km/h).
The R-6 design was developed in 1923 into the longer-winged XPW-8, the prototype of the PW-8 fighter.
In 1923, the CR-2s were fitted with floats for the Schneider Trophy race and redesignated CR-3.
The aircraft took first and second place, piloted by David Rittenhouse (average speed 177.977 mph (154.658 kn; 286.426 km/h) and Rutledge Irvine 173.932 mph (151.143 kn; 279.916 km/h).
After the 1924 Schneider Trophy race was cancelled, CR-3 A6081 was flown by Lt. G.T. Cuuddihy to set up new World’s closed-course seaplane record oc 188.07 mph (163.43 kn; 302.67 km/h).
A6081 was further modified as the CR-4 for use as a testbed and trainer for the 1926 Schneider Trophy racing team.
The first CR with US Navy serial A6080, with Lamblin radiators between the undercarriage struts.
The second CR A6081, fitted with streamlined wheels and wing surface radiators.
Both A6080 and A6081 were converted to CR-3 standard with floats and 475 hp (354 kW) Curtis D-12 5PL engines.
CR-3 A6081, modified as a testbed and trainer for the 1926 Schneider Trophy race team.
A refined version was developed for the US Army Air Service under the designation R-6