Hickman was a company dedicated to the purchase of surplus Lawrance engines from WWI, to convert them and improve the vibrational problems of the A-3 engines (see Lawrance).

-It turns out that in the original Lawrance the crankshaft had only one crankpin, moving both pistons and cranks in the same direction.

-To counteract the shuttle effects of this parts, he added a second crankpin in the same space. But he had to modify the connecting rods by bending them.

“Lawrance modified by Hickman”

-The architect of this work was Orville Hickman.

-The engine continued to maintain the arrangement of two horizontally-opposed cylinders.