Piper J-4

infobox Aircraft
name = J-4 Cub Coupe
type = Trainer
manufacturer = Piper


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produced = 1939-1941
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The Piper J-4 Cub Coupe was a two place side-by-side version of the Piper J-3 that was built between 1939 and 1941 by Piper Aircraft.

The first J-4s had a Continental A50, with up exhaust, an open cowl, oil and spring landing gear, a modified tail wheel system and many other changes. The early J4 had a comfortable cockpit but was slower than most side by side aircraft of the day. The 1940 J-4A gained a full pressure cowling, A65 engine, and aft auxiliary fuel. The final version was the 1941 J-4E which sported a 75hp Continental engine. The main fuel tank was moved to the wing along with a header tank and it also got a redesigned interior. Performance was now on par with other similar aircraft of the day, but the Pearl Harbor invasion sealed its fate.

Some J-4s had another unique feature in the tail construction, the stabilizer was made of stainless steel tubing, riveted together with gussets. The plane was Piper's first side-by-side, which made it a good trainer.