P.Bowers Curtiss Aircraft 1907-1947 (Putnam)
R-3 - Two R-3s delivered to the US Navy in 1916 were fitted with twin floats and 160 hp Curtiss V-x engines, Generally similar to the production R-2s, the R-3s had their wing spans increased to 57 ft 1 1/32 in (17,39 m) by the addition of a longer-span centre section for the upper wing and the insertion of extra panels on each side of the fuselage inboard of the standard-length outboard lower wing panels in the manner of the N-9. The wings were rigged without dihedral.
The original Navy identification/serial numbers for its two R-3s were AH-62 and AH-65 in the system adopted in March 1914; after 18 May, 1917, these became A66 and A67 in the new sequential serial number system and operated under their Curtiss model designations.
Eighteen R-3s were ordered by the US Army in 1916 for delivery in 1917, but these appear to have been completed as improved R-6s and R-9s.
R-3 - Observation seaplane. Pilot and observer. 160 hp Curtiss V-X.
Span 57 ft 1 1/32 in. (17,39m); length 30 ft 11 1/2 in (9,43 m); wing area 609,7 sq ft (56,64 sq m).
Empty weight 3,000 Ib (1,361 kg); gross weight 3,837 lb (1,740 kg).
R-6 (Model 2A) - The R-6 of early 1917 was a long-wing seaplane like the R-3 and differed from it mainly in use of the 200 hp V-2-3 engine and three degrees of dihedral in the outer wing panels. All but one of the seventy-six R-6s delivered to the US Navy had twin floats, serial number A193 being fitted with a single float. Army R-6s were delivered both as landplanes and as twin-float seaplanes. The US Army ordered 18, but most are believed to have been released to the Navy before Army acceptance.
Navy R-6s became the first American-built aeroplanes to serve US forces overseas in World War I when a squadron was assigned to patrol duty in the Azores in January 1918. Average cost of the R-6 and similar R-9 was $15,200 less GFE.
US Navy serial numbers; A162/197 (36), A302/34I (40). US Army serial numbers; 504/521
R-6L - Forty of the Navy's R-6s were converted to R-6L in 1918 by the installation of 360 hp low-compression Liberty engines in the manner of the R-4Ls of the Army. R-6Ls were used for the renewal of Navy torpedo-dropping experiments in 1920 and a number as Service torpedo aircraft until replaced by later equipment. The last R-6Ls were condemned in 1926. An additional fourteen R-6Ls were created by converting the R-9s with serial numbers A919, 920, 925, 943, 956, 958, 963/966, 970, 976, 991, and 994 to R-6 configuration.
Observation and torpedo seaplane. Pilot and observer. 360 hp Liberty.
Span 57 ft 1 3/16 in (17,4 m); length 33 ft 5 in (10,18 m); height 14 ft 2 1/32 in (4,31 m); wing area 613 sq ft (56,94 sq m).
Empty weight 3,513 lb (1,593 kg); gross weight 4,634 lb (2,102 kg), or 5,662 lb (2,568 kg) with torpedo.
Maximum speed 100 mph (160,93 km/h); climb in 10 min - 6,000 ft (1,829 m); service ceiling 12,200 ft (3,718 m): range 565 miles (909 km).
Armament - one 1,036 lb (470 kg) torpedo.
R-9 - The R-9 airframes for the Navy were bomber versions of the R-6 with the controls rearranged to place the pilot in the front seat and the observer/bombardier in the rear. Ten (A883/887, A901/905) were transferred to the US Army in February 1918.
US Navy serial numbers: A873/984 (112). US Army serial numbers: 39033/39042 (10)
G.Swanborough, P.Bowers United States Military Aircraft Since 1909 (Putnam)
CURTISS R SERIES
Eighteen nearly identical R-3s and R-6s (e.g. 505, 508) differed mainly in having 60-foot span 3-bay wings. Some R-6s were delivered as twin-float seaplanes; others converted to Liberty engines became R-6L (e.g. 39956). Some bomber conversions were re-designated R-9 (e.g. 39035/39042, 33748).
G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)
Curtiss R-3, R-6, R-9
The Curtiss R series of 1915-18 was widely used by the US Army and Navy and the Royal Naval Air Service for scouting, observation and training. The Navy models, as well as a few Army, were twin-float seaplanes originally powered with the 150hp Curtiss V-X engine As was common practice at the time, the pilot occupied the rear of the two cockpits while the observer sat in the front, although his vision was consequently handicapped by the wings. The basic design was merely an enlargement of the J and N models that had become standard Army observation and training models. The Army R-4 landplane model had a wing span of 48 ft 4 in, with two bays, but the Navy R-3 model, of which two were built, had the span increased to 57 ft 1 in in order to carry the weight of the floats. This was accomplished by building a wider centre section for the upper wing, in the manner of the N-9, and fitting an additional section between the standard-sized bottom wings and the fuselage.
The R-6 was an improved R-3 with a 200 hp Curtiss V-X-X engine and dihedral on the wings. A few of the Curtiss-powered R-6s were converted to R-9s, the main change being relocation of the pilot to the front cockpit. The last 40 of the Curtiss-powered R-6s were converted to R-6L in 1918 by the installation of the 360-400 hp V-12 engine, and an additional 40 R-9s were ordered as such. R-6s were the first US built aircraft to serve overseas with US armed forces in World War I, a squadron being based at Ponta Delgada in the Azores for anti-submarine patrols from January 17, 1918.
After the Armistice, R-6Ls were modified to carry naval torpedoes. The Navy had tried this on August 14, 1917, but the experiment was not successful. Such late adoption of the torpedo-carrier was rather ironic for the US Navy, as it had been an American admiral, Bradley A. Fiske, who had proposed such an aircraft before the outbreak of World War I. British and German forces both used torpedo-carriers successfully during that war, but the overall weight of the weapon cut down on the amount of explosive to such an extent that the torpedo was a less effective weapon than the standard aerial bomb.
TECHNICAL DATA (R-6L)
Manufacturer: Curtiss Aeroplane and Motor Co, Inc, Buffalo, NY.
Type: Observation, scouting and training.
Accommodation: Two in tandem.
Power plant: One 400hp Liberty V-12.
Dimensions: Span, 57 ft 1 1/4 in; length 33 ft 5 in; height 14 ft 2 in; wing area, 613 sq ft.
Weights: Empty, 3,325 lb; gross, 4,500 lb.
Performance: Max speed, 100 mph at sea level; climb 10 min to 6000 ft; service ceiling 12,200 ft; range, 565 st miles.
R-6: A162-A197; A873-A994.
Jane's All The World Aircraft 1919
This two-seat bomber appeared in 1916 and was used by the US Army and RNAS for training. Power was provided by a 200 h.p. Curtiss V-2 engine. Prom it was developed the R6 with the pilot in front (200 h.p. Curtiss or 375-400 h.p. Liberty engine) for observation and training, and the R9 with the same Liberty engine. R6s were the first American produced aircraft to serve abroad in the war (the Azores). The US Navy received examples of all three versions, but the R6 in the greatest number.
Upper 48' 4"
Chord 6' 3''
Gap 6' 2"
Stagger 1 3/4'
Length, overall, 28' 11 3/4"
Height 13' 2 1/4"
Incidence 2 1/2 degrees
Dihedral 3 degrees
Wing Curve R.A.F.6
Tail Plane No incidence
Surface (total) 505 sq.ft.
Wings (upper) 257 sq.ft.
(lower) 193 sq ft.
Aileron (upper) 17 sq.ft.
(lower) 10 1/4 sq. ft.
Total Aileron Surface 54 1/2 sq. ft.
Tail Plane 40 1/2 sq. ft.
Elevators (two) 27 1/2 sq. ft.
Fin (vertical) 7 sq. ft.
Rudder 16 1/2 sq ft.
Load per sq. ft. 6.42 lbs
Load per B.H.P. 15.89 lbs.
Net Weight (empty) 2225 lbs.
Gross Weight (full) 3245 lbs.
Useful Load 1020 lbs.
Petrol carried 625 lbs. (90 galls.)
Speed (max.) 90 m.p.h.
(min.) 48 m.p.h.
Climb 4000 ft. in 10 mins.
Motor (V2 type) 200h.p. 8-cyl.Curtiss