Columbia J2F-6 Duck
Single-engine two-seat military amphibian biplane, U.S.A.
Archive Photos 1
1947 Columbia (Grumman) J2F-6 "Duck" (N3960C, BuNo 33559) c.2005 at the Tillamook Air Museum, Tillamook, OR (John Shupek photos)
Grumman/Columbia J2F Duck Series Overview 2
- Grumman J2F Duck
- Role: Utility amphibian
- National origin: United States
- Manufacturer: Grumman; Columbia Aircraft Corp.
- First flight: 1936
- Introduction: 1936
- Primary users: United States Navy; United States Army Air Forces; United States Coast Guard; United States Marine Corps
- Number built: 584
- Developed from: Grumman JF Duck
The Grumman J2F Duck (company designation G-15) was an American single-engine amphibious biplane. It was used by each major branch of the U.S. armed forces from the mid-1930s until just after World War II, primarily for utility and air-sea rescue duties. It was also used by the Argentine Navy, who took delivery of their first Duck in 1937. After the war, J2F Ducks saw service with independent civilian operators, as well as the armed forces of Colombia and Mexico.
The J2F was an improved version of the earlier JF Duck, with its main difference being a longer float.
The J2F-1 Duck first flew on 2 April 1936, powered by a 750 hp (559.28 kW) Wright R-1820 Cyclone, and was delivered to the U.S. Navy on the same day. The J2F-2 had a Wright Cyclone engine which was boosted to 790 hp (589 kW). Twenty J2F-3 variants were built in 1939 for use by the Navy as executive transports with plush interiors. Due to pressure of work following the United States entry into the war in 1941, production of the J2F Duck was transferred to the Columbia Aircraft Corp of New York. They produced 330 aircraft for the Navy and U.S. Coast Guard. If standard Navy nomenclature practice had been followed, these would have been designated JL-1s, but it was not, and all Columbia-produced airframes were delivered as J2F-6s.
Several surplus Navy Ducks were converted for use by the United States Air Force in the air-sea rescue role as the OA-12 in 1948.
The J2F was an equal-span single-bay biplane with a large monocoque central float which also housed the retractable main landing gear, a similar design to the Leroy Grumman-designed landing gear first used for Grover Loaning's early amphibious biplane designs, and later adopted for the Grumman FF fighter biplane. The aircraft had strut-mounted stabilizer floats beneath each lower wing. A crew of two or three were carried in tandem cockpits, forward for the pilot and rear for an observer with room for a radio operator if required. It had a cabin in the fuselage for two passengers or a stretcher.
The Duck's main pontoon was blended into the fuselage, making it almost a flying boat despite its similarity to a conventional landplane which has been float-equipped. This configuration was shared with the earlier Loening OL, Grumman having acquired the rights to Loaning's hull, float and undercarriage designs. Like the F4F Wildcat, its narrow-tracked landing gear was hand-cranked.
Operational History 2
The J2F was used by the U.S. Navy, Marines, Army Air Forces and Coast Guard. Apart from general utility and light transport duties, its missions included mapping, scouting/observation, anti-submarine patrol, air-sea rescue work, photographic surveys and reconnaissance, and target tug.
J2F of the utility squadron of US Patrol Wing 10 were destroyed at Mariveles Bay, Philippines, by a Japanese air raid on 5 January 1942. The only Duck to survive the attack had a dead engine but had been concealed at Cabcaben airfield during the Battle of Bataan, to be repaired afterwards with a cylinder removed from a destroyed J2F-4 submerged in Manila Bay. Following repairs the J2F-4 departed after midnight on 9 April 1942, overloaded with five passengers and the pilot, becoming the last aircraft to depart Bataan before the surrender of the Bataan to the Japanese only hours later. Among its passengers was Carlos P. Romulo (diplomat, politician, soldier, journalist and author), who recounted the flight in his 1942 best-selling book I Saw the Fall of the Philippines (Doubleday, Doran & Company, Inc., Garden City, New York 1943, pp. 288–303), for which he received the Pulitzer Prize for Correspondence.
- J2F-1: Initial production version with 750 hp (559.28 kW) R-1820-20 engines, 29 built.
- J2F-2: United States Marine Corps version with nose and dorsal guns and underwing bomb racks, 21 built.
- J2F-2A: As J2F-2 with minor changes for use in the United States Virgin Islands, nine built.
- J2F-3: J2F-2 but powered by an 850 hp (633.85 kW) R-1820-26 engine, 20 built.
- J2F-4: J2F-2 but powered by an 850 hp (633.85 kW) R-1820-30 engine and fitted with target towing equipment, 32 built.
- J2F-5: J2F-2 but powered by a 1,050 hp (785.98 kW) R-1820-54 engine, 144 built.
- J2F-6: Columbia Aircraft built version of the J2F-5 with a 1,050 hp R-1820-64 engine in a long-chord cowling, fitted with underwing bomb racks and provision for target towing gear; 330 built.
- OA-12: Air-sea rescue conversion for the United States Army Air Forces (and later United States Air Force, OA-12A).
- Argentina: Argentine Naval Aviation received four new-build Grumman G-15s (equivalent to J2F-4s) in 1939, to supplement the eight Grumman G-20s (export version of the Grumman JF-2) received in 1937. In 1946–1947, 32 ex-US Navy Ducks (consisting of one J2F-4, 24 J2F-5s and 7 J2F-6s) were acquired, with the last examples remaining in use until 1958.
- Colombia: Colombian Navy (operated three examples from 1948).
- Mexico: Mexican Navy (operated three ex-U.S. Navy J2F-6s from 1950-1951).
- Peru: Peruvian Navy (operated one ex-USN example from 1961-1964).
- United States: United States Army Air Forces; United States Coast Guard; United States Marine Corps; United States Navy.
J2F-6 Specifications 3
- General utility amphibian for photographic, target-towing, rescue, ambulance and other similar duties.
- Equal-span single-based staggered biplane.
- Upper wing in two sections joined at the center-line and carried above the fuselage on splayed-out struts and braced to the lower wings by N-type interplane struts.
- No transverse bracing in the center-section struts but vertical wires from strut attachments on wings to bottom of fuselage.
- Lift and anti-lift wires in plane of upper rear and lower front wing spars.
- Wing structure of metal with fabric covering.
- Spars have two extruded channels section booms with a wandering web related alternatively to front and rear faces of channels.
- Spot-welded steel girder ribs.
- Frise ailerons on all four wings.
Hull and Fuselage
- Single-step hull is a metal monocoque of aluminum alloy.
- Internal bracing of cross-floor type with longitudinal stresses taken by skin, with reinforcement from chines and keel and from inverted U-members riveted to deck and forward section.
- The hull is stressed to catapult launching and deck arresting.
- Braced monoplane type.
- All-metal thin and tailplane.
- Rudder and elevators have aluminum-alloy frames and fabric covering.
- Trim-tabs in rudder and elevators.
- Combined tail-wheel and water-rudder has self-centering lock.
- Consists of two oleo shock-absorber struts with their upper ends hinged to extensions on two fore-and-aft revolving tubes and with their lower ends attached to axle-blocks which are hinged to the chines of the hull by steel-tube Vees.
- Retractable type.
- Retraction by chains and sprockets.
- Wheels are raised into recesses in the size of the hull.
- One 900 hp (671.13 kW) Wright R-1820-54 nine-cylinder radial air-cooled engine driving a three-blade Hamilton Standard constant-speed airscrew.
- NACA cowling.
- Fuel tanks in fuselage.
- Capacities: main tank 150 U.S. gallons (567. 81 L), auxiliary tank 65 gallons (246.05 L).
- Tandem cockpits under a continuous transparent canopy with opening sections over each cockpit.
- Folding door in rear cockpit gives access to lower compartment in which two persons may sit side-by-side.
- External doors on each side of lower compartment, which may also accommodate one stretcher case, target-towing gear, etc.
- Span: 39 ft (11.9 m).
- Length: 34 ft (10.37 m).
- Height on wheels: 13 ft 11 in (4.25 m).
- Wing area: 409 ft2 (38 m2).
- Loaded weight: 7,700 lbs (3,496 kg)
- Maximum speed: 190 mph (304 km/h).
- Cruising speed: 155 mph (248 km/h).
- Stalling speed: 70 mph (112 km/h).
- Service ceiling: 20,000 ft (6,100 m).
- Shupek, John. The Skytamer Photo Archive, photos by John Shupek, copyright © 2005 Skytamer Images (Skytamer.com)
- Wikipedia, the free encyclopedia. Grumman J2F Duck
- Bridgeman, Leonard. Jane's All the World's Aircraft 1945-46, Grumman: The Grumman Duck, London: Sampson Low, Marston & Company, LTD., 1946, pp. 265c.