Jacobs Aircraft Engine Company
# Jacobs Aircraft Engine Company

The Jacobs Aircraft Engine Company was an American aircraft engine manufacturer that existed from 1926 to 1956.

## History

### Early years

The Jacobs Aircraft Engine Company was formed in 1926 in Philadelphia. Later the company moved to Pottstown, Pennsylvania after purchasing the machine workshop of the Light Manufacturing and Foundry Company.

### Early engines

An early product was the 1931 L-3, a 190.4 cu in (3,120 cc) 51 hp (38 kW) three-cylinder air-cooled radial engine. Only 44 were built.

By 1933, Jacobs had developed its most famous engine, the L-4 seven-cylinder air-cooled radial, with a power rating of 225 hp (168 kW) displacement of 757.7 cu in (12,416 cc). It was better known as by its military designation, R-755. At the time it became known as the best producer of engines in the 200-400 horsepower range. Jacobs was the first to start making engines using forged aluminum alloy pistons, sodium-filled exhaust valves, and magnesium alloy crankcases.

The L-4 was used mostly on the Cessna Bobcat, Cessna 195, and Stearman Kaydet.

Due to the tendency of the L-4 engine to vibrate heavily at low rpm, it was given the nicknames Shakin' Jake and Shakey Jake.

### Later models

Later developments included the 285 hp L-5 or R-830, and 330 hp L-6 or R-915.

### Postwar

Jacobs was acquired by Republic Industries in 1945, which was in turn acquired by Barium Steel Corporation in 1946. However in 1947, the company was sold back to Albert Jacobs. Jacobs Aircraft Engines went into default in 1950 and was again sold back to Republic. Finally, Barium sold the company in December 1956 and it closed a few months later in 1957.

## Applications

Jacobs engines were fitted to many US-built aircraft of the inter-war period, including several Waco models. They were in use in 26 different countries including in Canada, where 330 horsepower L6-MB engines were used to power the Royal Canadian Air Force's Avro Anson Mk. II aircraft. In 1941 the American War Department gave the contract to Jacobs to produce Pratt & Whitney R-985 and R-1340 engines until 1945. Jacobs ranked 87th among United States corporations in the value of World War II military production contracts.

## Products

| Model name | Configuration | Power |
| - | - | - |
| Jacobs LA-1 | R7 | 140 hp |
| Jacobs LA-2 | R7 | 195 hp |
| Jacobs L-3 | R3 | 51 hp |
| Jacobs L-4 | R7 | 225 hp |
| Jacobs L-5 | R7 | 285 hp |
| Jacobs L-6 | R7 | 330 hp |
