John Chothia designed engines that are manufactured by "Weedhopper of Utah Inc.".

-These engines are adapted for ultralights, with high torque at low rpm, especially the 460 model engines.

-The first Chothia gave 18.5 hp, which was subsequently increased to 25 hp at 3,600 rpm.

-It was known as Roundhead.

-Interestingly, the ignition is powered by four type-D alkaline batteries, which last about 20 to 25 Hrs. The engine weighs 14.2 kg., and has a displacement of 456 cc (not exactly 460 as designated). Consumption is only 5.6 liters/hr. of mixture.

"Chotia"

-The type D flashlight battery system seems unsafe but from the first notice to exhaustion there are still four hours of cruising speed left. Installation is very simple.

-The 460C model that gives 30 hp at 3,800 rpm weighs 56 pounds complete with Mikuni carburetor and fuel pump.

"Chotia cutaway"

-Finally, the 460D model is a last Standard engine.

-Chotia was one of the first engines used in ULM. The one shown in the cutaway is known as Squarehead.

From appendix 6: We have two Chotia engine installations of the types mentioned in the main text.

"Two-stroke, with two sparkplugs"

“Squarehead version” (Photos RL, AEHS)

From appendix 9: At the National Automobile Museum in Encamp, Andorra, they expose an air-cooled engine with a single-cylinder on one side to be used in ultralight.

"Chotia"

-We see that it has dual ignition. Perhaps it is the same engine that appears upright in the main text.