The Curtiss R-2 was a two seat observation aircraft that served with the US Army, and in larger numbers with the RFC, and that was essentially an enlarged version of the Curtiss Model N.
Curtiss’s earliest attempts to produce tractor aircraft hadn’t been successful, so they decided to hire a British engineer, B. Douglas Thomas, who had been working for Sopwith. He helped design the Model J and the Model N, two fairly small aircraft that led to the Model JN (Jenny), by far the most significant American designed aircraft of the First World War.
The original Model R (Curtiss Model 2) was designed in an attempt to produce a larger and more advanced aircraft than the J and N. It was powered by a 160hp Curtiss V-X, which was itself a larger version of the Curtiss OX family used in the JN. It had level equal span wings using an RAF 6 aerofoil, with shoulder yoke controls for the ailerons, which were carried between the wings. The wings were heavily staggered, with the upper wing significantly ahead of the lower wing. The two crew sat in a single large cockpit, with the observer sitting in front and the pilot at the rear. This layout was chosen so that the observer was sitting at the centre of gravity, and the aircraft would thus be balanced the same if they weren’t present. However it did mean that the pilot’s view was obstructed by the observer. One example of the Model R was produced. It was tested with wheels and as a single plane seaplane, and the wings were later modified to give them some dihedral.
The Curtiss R-2 was the first production version of the aircraft, and was developed during 1915. It was extensively altered compared to the Model R. The engine remained the same, as did the car style radiator in the nose. The single cockpit was replaced with two separate cockpits, with the observer in the front cockpit, which was located between the wings, and the pilot in the rear cockpit. The wings were unequal span, with the longer upper wing carrying the ailerons. They had some dihedral. The undercarriage was redesigned as was the tail, which now had a fixed vertical fin and an unbalanced rudder (replacing the all moving rudder of the Model R).
One R-2 was modified to have a propeller spinner and dual radiators mounted on either side of the fuselage in place of the nose radiator, but this wasn’t adopted for production and the entire R family kept the nose radiator.
Twelve of the standard R-2s were sold to the US Army in 1916 (serial numbers 64 to 75), at a cost of $12,000 each. Some of them saw service with Pershing’s Mexican Punitive Expedition. Pershing was generally unimpressed with the performance of this aircraft during this expedition.
The largest customer for the R-2 was the British, who purchased 100 examples (serial numbers 3445-3544). These aircraft were powered by a 200hp Sunbeam Arab II engine. These aircraft were probably used by the by the RNAS, as their serial numbers are in the range allocated to that service.
One example of the Curtiss R-2A was also produced. This was produced in parallel with the R-2, and had the same separate cockpits, new tail and new landing gear. However it retained the equal span wings and inter-plane ailerons of the Model R. In August 1915 a Curtiss pilot, Raymond V. Morris, set an American altitude record of 8,105ft for an aircraft carrying a pilot and three passengers.
The R-2 was followed by the Curtiss R-3, a twin float-plane reconnaissance aircraft. Only two of these were built, but they were followed by larger numbers of the similar Curtiss R-6 and Curtiss R-9. The Army also ordered a number of the Curtiss R-4, a land plane version with a more powerful engine and other minor changes.
Engine: Curtiss V-X (RFC Sunbeam Arab II)
Power: 160hp (RFC 200hp)
Crew: 2 – pilot and observer
Span: 45ft 11.5in (upper), 38ft 4 7/8in (lower)
Length: 24ft 4 3/8in
Empty weight: 1,822lb
Gross weight: 3,092lb
Maximum take-off weight:
Max speed: 86mph
Climb Rate: 4,000ft in 10 minutes
Endurance: 6.7 hours at cruising speed