Towards 1909/10, DeHavilland made a first design of an aviation engine, which was built by the Iris Motor Company.

“Iris”

It was a horizontally-opposed, four-cylinder engine with 4.984 liters of displacement.

-It was water-cooled without pump, and by "thermosyphon".

“Students with an Iris engine”

-A curious photo shows us some apprentices working on an Iris engine.