The Curtiss Model R was a utility aircraft produced for the United States Army and Navy during World War I. It was a conventional, two-bay biplane with slightly staggered wings of unequal span. The aircraft was provided with two open cockpits in tandem and fixed tailskid undercarriage, but many were built for the Navy with twin floats replacing the wheels. During the course of the war, Model Rs were used for general liaison and communication duties, as well for observation, training, and as air ambulances. In practice, the Curtiss powerplants supplied with these aircraft proved insufficient and were mostly replaced with Liberty engines. The Navy's Model R-3 floatplane had extended-span, three-bay wings, and was intended for use as a torpedo bomber. Some of these were later fitted with wheeled undercarriage and transferred to the Army as bombers under the designation Model R-9.
United KingdomRoyal Navy Air Service United StatesUnited States ArmyUnited States NavyModel RPrototype with highly-staggered, equal-span wings and with single long cockpit for pilot and observer. Powered by 160 hp (119 kW) Curtiss V-X engine.
Model R-2Initial production version, fitted with uneven-span staggered wings and individual, widely-separated cockpits for pilot and observer. 12 built for US Army and 100 for Royal Navy Air Service.
Model R-2AOne-off version, with equal-span wings, which broke the American altitude record of 8,105 ft (2740 m) in August 1915. One built.
Model R-3Floatplane version for the US Navy, with increased wingspan (57 ft 1 in) wings. Two built.
Model R-4Improved version of R-2 for US Army, powered by 200 hp (149 kW) Curtiss V-2-3 engine. At least 55 built.
Model R-6Two-seat floatplane with long-span wings of R-3 but powered with Curtiss V-2-3 engine. 76 delivered to US Navy plus some floatplanes and landplanes for US Army. Used for torpedo-bomber trials post war.
Model R-7Long range landplane built for the New York Times for an attempted to fly non-stop from Chicago to New York in 1916. It failed to complete the flight but still set an American distance record of 452 miles (727 km). Fitted with long-span wings as R-3 and R-6 and powered by Curtiss V-2-3 engine. One built.
Model R-9Two-seat bomber version for the US Navy, similar to R-6, but with crew positions reversed so pilot sat in front cockpit and observer in rear. 112 built for the US Navy, ten of which transferred to US Army.
Pusher R1916 pusher version, based on wings of R, with new fuselage nacelle accommodating two crew. One built.
Twin ROne-off experimental twin-engined conversion of R-2.
Data from Curtiss Aircraft 1907–1947
General characteristics
Crew: one pilotCapacity: one passengerLength: 14 ft 4⅜ in (7.43 m)Wingspan: 45 ft 11½ in (14.01 m)Wing area: 505 ft2 (46.9 m2)Empty weight: 1,822 lb (826 kg)Gross weight: 3,092 lb (1,402 kg)Powerplant: 1 × Curtiss V-X, 160 hp (120 kW) eachPerformance
Maximum speed: 86 mph (138 km/h)Endurance: 6 hours 42 min 
