1910 Jopson Motor: Flight!

The 1910 Jopson Gasoline Motor weighed 7.5 pounds and had a unique wick carburetor system installed in a tank without any sort of pressurization.  Could it actually power a model airplane in flight?

Yes!  …. Or, well, we’re pretty sure.

Photographs published in the book Model Aeroplaning: Its Practice and Principles, by V.E. Johnson in 1922 show the motor installed in a model airplane by T.W.K. Clarke.  According to the text, adding the battery and coil to the motor increased its weight to 8 lbs 14 ozs, a bit more than the model airplane itself, which weighed 7 lbs 2 ozs.  It took a wingspan 96 inches to get all of it into the air.

A full side view of Clarke's model aircraft with the Jopson motor installed.  Photo from V.E. Johnson's book Model Aeroplaning: Its Practice and Principles, 1922.
Jopson Motor installed in T.W.K. Clarke’s model aircraft. Photograph from Johnson, V.E. Model Aeroplaning: Its Practice and Principles, London: F.N. Spon, 1922.

Note that the engine was installed in the model pusher fashion, with the tank pointing towards the model’s front canard (which measured 42”), and the prop facing the back of the model.

A front 3/4 view of the Jopson motor installed in Clarke's model aircraft.  Photo from Johnson's Model Aeroplaning: Its Practice and Principles, 1922.
Jopson Motor installed in T.W.K. Clarke’s model aircraft. Photograph from Johnson, V.E. Model Aeroplaning: Its Practice and Principles, London: F.N. Spon, 1922.

Despite all of the information provided on Clarke’s model (including his closing statement, “Note the neatness and compactness of the plant, also its high position and the large size of the propeller.”), what he doesn’t provide is details about any flight made with the model.  T.W.K. Clarke, though, sold both model airplanes and full-scale airplanes, and was an active modeler and a frequent contributor to Flight magazine, so there’s every reason to expect that he tried to get the model off the ground with the engine running.  If any details of these attempts exist, however, they’ve yet to be located.

A close-up view of the Jopson motor installed in Clarke's aircraft.  Photos from Johnson's Model Aeroplaning: Its Practice and Principles, 1922.
Jopson Motor installed in T.W. Clarke’s model aircraft. Photograph from Johnson, V.E. Model Aeroplaning: Its Practice and Principles, London: F.N. Spon, 1922.

p.s. – Want some fun reading?  The information on T.W.K. Clarke was taken from page 219 of Model Aeroplaning. Reading on to 220 and 221 gets you some very early thoughts on using electric motors, and a funny anecdote about a “rocket-powered” model airplane!

Come and see the 1910 Jopson Motor on exhibit between Memorial Day and Labor Day 2017!

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For more information on the National Model Aviation Museum, including our location, hours and admission fees visit: www.modelaircraft.org/museum

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