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Grumman J2F Duck

In 1932 Grumman submitted their design for the amphibious G-7 to the U.S. Navy to meet the Navy's specifications for a plane in the "Utility" category. The Navy accepted the plane in 1934 as the JF-1, and ordered 27 of the aircraft.

The "Duck" became one of the Navy's all-around workhorses, and was used before and during WWII as a transport, reconnaissance plane, bomber, and rescue plane. Although often referred to as a floatplane, the central float is integral with the fuselage, making the plane a flying boat in truth. The plane seats two crew members in the dorsal cockpit, the pilot and an observer/radio operator/rear gunner (depending upon the plane's role). In the central fuselage, just above the main float, there is space for two passengers or a stretcher. A set of landing gear and an arrestor hook rounded out the plane, making it capable of operating from carriers, airstrips, or the water.

The Duck burns 34.6 gallons of fuel per hour. A full load of fuel costs $43.

 

Grumman J2F Duck

Subassemblies: Light Fighter-Bomber chassis +3; Medium Fighter wings with Biplane option +2; 3 retractable wheels +1; one Small AFV Waterproofed pontoon [Body:U] +2; two Small Weapon Waterproofed pontoons [Wings:U] +0.

Powertrain: 691-kW Aerial supercharged HP gasoline engine with 691-kW prop; one 150-gallon main fuel tank [Body] and one 65-gallon auxiliary fuel tank [Body]; 4,000-kW battery.

Occ.: 2 CS Body, 2 PS Body

Cargo: 0 Body

 

Armor F RL B T U

Body: 2/3 2/3 2/3 2/3 2/3

Wings: 1/2C 1/2C 1/2C 1/2C 1/2C

Wheels: 2/3 2/3 2/3 2/3 2/3

Pontoons: 2/3 2/3 2/3 2/3 2/3

 

Weaponry:

Aircraft LMG/.30-cal Browning LMG [Body:B] (1,000 rounds).

 

Equipment:

Body: Navigation instruments, arrestor hook, medium range radio transmitter and receiver with direction finder, casemate mount. Wings: two 325-lb. hardpoints.

 

Statistics:

Size: 34'x39'x14' Payload: 0.92 tons Lwt.: 3.85 tons

Volume: 312 Maint.: 38 hours Cost: $27,123

HT: 9. HPs: 165 Body, 160 each Wing, 15 each Wheel, 150 central Pontoon, 45 each wing Pontoon.

aSpeed: 190 aAccel: 5 aDecel: 15 aMR: 4 aSR: 1

Stall Speed: 59 mph. Take Off Run: 316 yards. Catapult Launch: 280 yards. Landing Run: 348 yards.

gSpeed: 214 gAccel: 11 gDecel: 10 gMR: 0.5 gSR: 2

Ground Pressure: Very High. 1/8 Off-Road Speed.

wSpeed: 36 wAccel: 5 wDecel: 2 (4.5) wMR: 0.1 wSR: 4

Draft: 1.5 feet. Flotation Rating: 15,702 lbs.

 

Design Notes:

Historical wing area was 409 sf. Design loaded weight was 9,327 lbs. This is 17% above the historical, but the design includes equipment for all of the Duck's historical roles. Likely, the plane would only be equipped for a specific mission parameter. Removing all ordnance for a transport/rescue role, for example, reduces weight to within 10% of the historical. MG load-outs are a guess. Design aSpeed was 198 mph fully loaded. Historical loaded weight and wing area for all performance calculations. Historical stall speed was 70 mph, but his made the design unable to lift off from water, so the design stall speed was used for landing and take-off performance calculations.

 

Variants:

The JF-1 (or G-7) (1933) was the initial production model. It featured 100-lb. wing hardpoints and a 522-kW engine. 27 built.

The JF-2 (or G-9) (1934) was similar to the JF-1, but mounted a radio direction finder. The antenna interfered with the field of fire from the MG, and so was removed whenever the Browning was installed. There was no arrestor hook. 14 built.

The JF-3 (or G-10) placed the antenna in the cockpit, resolving the MG issue. There was no arrestor hook. 5 built.

The J2F-1 (1936) featured a 560-kW engine. The arrestor hook was reinstalled, and the bombload increased. 20 built.

The J2F-2 was equipped with a 589-kW engine, and a forward facing Browning MG. 21 built. The USMC's -2A had twin MGs for the gunner and an extra pair of bomb racks. 9 built.

The J2F-3 (1939) was J2F-2s fitted with luxury accommodations for transporting naval officers. 20 built.

The J2F-4 (1939) featured minor modifications to the J2F-2. 32 built.

The J2F-5 (1941) installed a 708-kW engine and an increased bomb load. 124 built.

The J2F-6 (1942) was the -5 built by Columbia Aircraft Corporation. (Grumman had begun working on more significant aircraft following the attack on Pearl Harbor.) The powerplant was upgraded to 783-kW. 330 built for the Navy and Coast Guard.

The AO-12, -12A, and -12B were a modification of nine -5 and -6 Ducks between 1942 and 1948 for air/sea rescue used by the USAF.

The G-15 and G-20 were -5 and -6 Ducks produced and exported to Columbia, Argentina, and Mexico.

 

From the Aerodrome for GURPS

2008 by Jim Antonicic