Gnome monosoupape (single valve) Rotary Radial Aero Engine

in which the cylinders rotated with the propeller around a fixed crankshaft, was designed by the Seguin brothers in France in 1907 and marked the first complete break from traditional automobile engine design. Gnomes with varying numbers of cylinders and giving powers up to 180 horsepower were made in large quantities until late in the 1914-18 War.

Gnome with cams exposed

A cam, B cam roller, D ball joint, E hollow valve rod, F rocker arm


Gnome on running stand


Gnome cross-section shows one cylinder in the vertically upright position


fuel is forced into crankcase through the jet inside the crank at F, and enters the cylinder when the piston is at it's lowest position, through openings at A and B. The exhaust is through a large single valve which gives rise to the name "monosoupape" or single valve motor. Oil enters at C, through the stationary crankshaft, goes through the stationary crank at D, and floods the bearings at E.

Gnome plumbing diagram

the above was scanned from:
Aircraft Mechanics Handbook
by Fred H. Colvin, A. S. M. E.
stamped on inside of front cover:
Navy Department

Navy Department
Naval Air Station, San Diego, CAL.
"Commanding Offceers Copy" hand written.
I also have a pretty good library.

Gnome Cycle timing

[missing] [missing]

typical radial engine connecting rod, But not Gnome,.
Note: all of the Gnome Connecting Rods are articulated.
This diagram answers a lot of questions, about how does a Radial Engine work.

SAITO Radial 4 Stroke engine parts list and exploded view


Beautiful Model Gnome Rotary Aero Engine, with photos of internal

Pete's Photo Gallery, Gnome Rotary Aero Engine

Radial engine plans and castings, model steamboat information and animation

A Brief Radial engine History
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