Piper began work on a lower-cost replacement for the PA-39 Twin Comanche in 1974. The “Twin Arrow”—Project 10—was headed by Grahame Gates at Piper Aircraft’s Lakeland plant.

Original specs called for what was basically an Arrow fuselage with T-tail, but using the same gross weight and 160 hp counter-rotating L/IO-2-B1A engines as the Twin Comanche C/R.

The project was moved to Vero Beach in 1975 and renamed “Light Twin.” Engines were upgraded to 180 hp to allow for an acceptable rate of climb. The rear of the aircraft was re-engineered and a smaller T-tail was fitted in 1977. Next, engineers added a longer rear fuselage and new ailerons.


In 1978 Piper announced its new model at a meeting of Piper dealers. The Piper representative explained that “the Seminole joins Piper’s twin-engine line with a distinctive T-tail, counter-rotating propellers, and semi-tapered wings. It is the ideal aircraft for the single-engine pilot to step up to twin-engine flying.”

“The balance of purchase price, operating cost, and performance make the Seminole an excellent multi-engine trainer,” he continued.

The first production Seminole—N9666C—flew in May 1978 and deliveries began in July 1978. The Seminole came equipped with a new fuel drain sump system which had only two drains for the entire system, both on the right side to allow for easy access. Fuel was stored in two nacelle fuel tanks. Base price was $73,900.

The 1980 model offered an improved ventilation system and options for three-blade propellers and prop synchrophaser. Production of the normally aspirated Seminole was halted in 1981.

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