Piston Engines
A piston engine designation has three separate elements, a type prefix, a number representing engine displacement and a model number.
- Type Prefix
- The type prefix is based on the engine disposition:
| H | Two-row inline |
| L | Inline |
| O | Opposed |
| R | Radial |
| V | Vee |
| W | W engine |
| X | X engine |
Some early engines had the type letter prefixed by a modification letter
- G - geared
- I - inverted
- S - supercharged
- Displacement
- A number related to the engine displacement within 5 cubic inches.
- Model Suffix
Letters were used between 1926 and 1933 then suffixes were numerals with odd number for Army and later Air Force engines and even numbers for Navy engines. After 1943 the letters AN were included to indicate the engine met both Army/Air Force and Navy requirements. Some engines fitted with water-injected engines had the W added to the suffix.
For example the Curtiss V-1150-1 is a Vee-type engine with a displacement of 1150 cubic inches and is an Army model.
Read more about this topic: United States Military Aero Engine Designations
Famous quotes containing the word engines:
“America is like one of those old-fashioned six-cylinder truck engines that can be missing two sparkplugs and have a broken flywheel and have a crankshaft that’s 5000 millimeters off fitting properly, and two bad ball-bearings, and still runs. We’re in that kind of situation. We can have substantial parts of the population committing suicide, and still run and look fairly good.”
—Thomas McGuane (b. 1939)