Piper introduced the Cub Coupe in 1938 and it went into production the next year, gaining immediate popularity, particularly with pilot sports who liked to take their gals for a ride and hold hands side-by-side. It came out with, wheel pants, full-swivel tailwheel, oleo gear in the under-carriage, and even an airspeed indicator. It had a small increase in wing span and introduced improved landing gear with a fully-castoring tailwheel, and hydraulic brakes. As powered initially by a 37kW Continental A50-1 it had the designation J-4.
The J-4 Coupe was developed and introduced shortly after Taylor brought out his highly successful Taylorcraft Model B side-by-side two seater. Taylor had designed the Piper Cub, and when he split with Piper he decided to offer an airplane better than the Cub was. Piper engineers countered with the J-4 and the market was offered the choice between two airplanes of generally similar configuration.
The initial J-4 Cub Coupes (ATC 703) designed by Walter Jamouneau and Hanford Eckman, were plush inside, upholstered in suede cloth and leather. Elevator tab control and indicator were put up in the ceiling, in front of the pilot’s head where you could see whether you were winding the nose up or down. They were priced at $1,995, with exposed engine cylinders.
The 1938 J-4A (703) was powered by a 65hp Continental A-65 engine with enclosed cowl.
In 1939 Piper introduced the J-4B (ATC 708), differing only in powerplant which initially, was a 45kW Franklin 4AC-171, but that was soon replaced by the 48kW Franklin 4AC-176-B2 without any change in designation. Priced at $1,935, nineteen J-4A and -4B in England were impressed by RAF.
Introduction of the 56kW Continental A75-9 in 1941 brought redesignation as the J-4E (ATC 740), priced at $2,395.
Last of the J-4s was the version powered by Avco Lycoming engines, the 41kW O-145-A1 or -A2, or 48kW O-145-B1, both of these Cub Coupes having the designation J-4F, priced at $1,910.
One J-4, NX21599, was experimental fitted with 60hp Milwaukee Tank engine.
Powered by a 75hp Continental engine, the J-4RX [NX22941 of 1939 tested an experimental William Rose wing with slats, slotted ailerons, and flaps.
By 1941, with production rolling on the Coupe, Piper’s 70-horsepower version came out with. increased speed, range, and altitude, and sold at $2,395, only $799 down, with a free flying course including eight hours of dual time thrown in so you could fly your toy home from Lock Haven all by yourself – hopefully.
This was a step forward from originally published claims for the Cub Coupe, which sold in 1938 for $1,995, only $665 down with a free catalog thrown in. Announced Piper: “Get this luxurious 1939 Cub Coupe and you’ve got everything! Here’s a plane that’s complete in every detail. Nothing more to buy!”
Production of J-4s reached 1,250 by 1942, and during World War II 17 J-4Es were impressed for service with the USAAF under the designation L-4E. 1942 impressed J-4E 42-79555 was first designated UC-83B, later becoming L-4E.
J-4
Engine: Continental A-50, 50 hp
Span: 36 ft 7 in
Length: 22 ft 6 in
Height: 6 ft 10 in
Empty wt: 710 lb
Gross weight: 1,200 lb
Useful load: 590 lb
Top speed: 93 mph
Cruising speed: 83 mph
Landing speed: 35 mph
Cruising range: 340 miles
Climb first minute: 500 fpm
Service ceiling: 12,000 ft
Range: 325 mi
Seats: 2
J-4A
Engine: 65hp Continental A-65
J4A 65 Cub Coupe
Engine: Continental A65-8, 65 hp
J-4B
Engine: 60hp Franklin 4AC
Useful load: load: 520 lb
Max speed: 96 mph
Cruise: 85 mph
Stall: 36 mph
Range: 340 mi
J-4B
Engine: 65hp Franklin 4AC-B2
J-4E
Engine: 75hp Continental A-75
Useful load: 575 lb
Max speed: 105 mph
Cruise:98 mph
Stall: 37 mph
Range: 460 mi
Piper J-4F
Engine: 1 x Avco Lycoming O-145-B1, 48kW / 60 hp
Wingspan: 11.02 m / 36 ft 2 in
Length: 6.86 m / 23 ft 6 in
Height: 2.08 m / 7 ft 10 in
Wing area: 17.00 sq.m / 182.99 sq ft
Max take-off weight: 590 kg / 1301 lb
Empty weight: 336 kg / 741 lb
Useful load: 480 lb
Max. speed: 161 km/h / 100 mph
Cruise: 85 mph
Stall: 35 mph
Ceiling: 3660 m / 12000 ft
Range: 547 km / 340 miles
J-4F
Engine: 65hp Lycoming O-145
Wingspan: 11.02 m / 36 ft 2 in
J-4F
Engine: 60hp Milwaukee Tank
Wingspan: 11.02 m / 36 ft 2 in
J-4RX
Engine: 75hp Continental
All Aero 