A flat-ten engine, also known as a horizontally opposed-ten, is a ten-

cylinder A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...

piston engine A reciprocating engine, more often known as a piston engine, is a heat engine that uses one or more Reciprocating motion, reciprocating pistons to convert high temperature and high pressure into a Circular motion, rotating motion. This article ...

with five cylinders on each side of a central

crankshaft A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...

. There are no known flat-ten engines which reached production. In the early 1960s,

Chevrolet Chevrolet ( ) is an American automobile division of the manufacturer General Motors (GM). In North America, Chevrolet produces and sells a wide range of vehicles, from subcompact automobiles to medium-duty commercial trucks. Due to the promi ...

built several prototype flat-ten engines as part of an aborted program for family of ''Modular Engines'' to replace the Chevrolet Turbo-Air 6 flat-six engine. This development program investigated

flat engine A flat engine is a piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common opposed-piston engine design, ...

s with between two and twelve cylinders, with the flat-ten version being known as "P-10" ("pancake" engine). Although the program was initially intended to develop an engine for the 1964

Chevrolet Corvair The Chevrolet Corvair is a Rear-engine design, rear-engined, Chevrolet Turbo-Air 6 engine, air-cooled compact car manufactured and marketed by Chevrolet over two generations between 1960 and 1969. A response to the Volkswagen Beetle, it was of ...

(which is rear-engined with rear-wheel drive), the flat-ten version was fitted to an experimental 1962

Chevrolet Impala The Chevrolet Impala () is a full-size car that was built by Chevrolet for model years 1958 to 1985, 1994 to 1996, and 2000 to 2020. The Impala was Chevrolet's popular flagship passenger car and was among the better-selling American-made auto ...

(a front-engined car which was converted to front-wheel drive).

References

Piston engine configurations 10 {{Automotive-part-stub