The Armstrong Siddeley Ounce was a small two-cylinder aero engine developed by Armstrong Siddeley in 1920.

[1] The engine was originally conceived as a test piece but ran very well and was put into production for early ultralight aircraft and use in target drones.

The Ounce used two cylinders from the preceding Jaguar I radial engine.

Data from Lumsden.

[2] Comparable engines Related lists