Piper J-4

J-4 Cub Coupe
Piper J-4A Cub Coupe displayed at the Pima Air Museum, Tucson, Arizona in 2005
General information
Type	Trainer and private owner aircraft
Manufacturer	Piper
Status	Many still flying as of 2024
Number built	1,251
History
Manufactured	1938-1942
Introduction date	1938
First flight	May 1938

The Piper J-4 Cub Coupe is a two place side-by-side version of the Piper J-3 that was built between 1938 and 1942 by Piper Aircraft. It was Piper's first model with side-by-side seating.

The fuselage of the J-4 was wider than the J-3 and the aircraft had a fully enclosed rear decking to the fuselage top.^[1] The first J-4s had a Continental 50 hp A50 engine with upward-facing exhaust ports, an open cowl, oil and spring landing gear, a modified tail wheel system and many other changes. The early J-4 had a comfortable cockpit but was slower than most side by side aircraft of the day.

The 1940 J-4A gained a fully enclosed cowling, a Continental 65 hp A65 engine, and aft auxiliary fuel. The J-4B was fitted with a 60 hp Franklin 4AC-171 engine.^[2] The final version was the 1941 J-4E which sported a 75 hp Continental engine and redesigned interior. The main fuel tank was moved to the wing along with a header tank. Performance was now on par with similar contemporary types, but the attack on Pearl Harbor sealed its fate as all civilian aircraft manufacture came to a stop with the entry of the United States into World War II.^[3]

Some J-4s had another unique feature in the tail construction: the stabilizer was made of stainless steel tubing, riveted together with gussets.

J-4

powered by a 50-hp (37-kW) Continental A50-1 piston engine.

J-4A

powered by a 65-hp (48-kW) Continental A65-1 or -8 piston engine.

J-4B

powered by a 60-hp (45-kW) Franklin 4AC-171 or 65-hp (48-kW) 4AC-176-B2 piston engine.

J-4E

powered by a 75-hp (56-kW) Continental A75-9 piston engine.

J-4F

powered by a 55-hp (41-kW) Avco Lycoming O-145-A1, -A2 or 65-hp (48-kW) O-145-B1 piston engine.

General characteristics Performance

Data from Simpson, 2001, p. 430.

General characteristics

• Length: 22 ft 6 in (6.86 m)
• Wingspan: 36 ft 2 in (11.02 m)
• Height: 6 ft 10 in (2.08 m)
• Gross weight: 1,300 lb (589.67 kg)
• Powerplant: 1 × Continental A65-1 piston engine , 65 hp (48 kW)

Performance

• Maximum speed: 100 mph (160.93 km/h, 87 kn)
• Cruise speed: 92 mph (148.06 km/h, 80 kn)
• Range: 360 mi (579.36 km, 310 nmi)
• Service ceiling: 15,000 ft (4,572 m)
• Rate of climb: 600 ft/min (3.04 m/s)

Related development

• Piper J-3 Cub

Aircraft of comparable role, configuration, and era

• Aeronca 50 Chief
• Cessna 120 and 140
• Ercoupe
• Luscombe 8
• Taylorcraft B

Related lists

• List of aircraft of World War II

Notes

Bibliography

Media related to Piper J-4 at Wikimedia Commons