Go ahead...Google the word "doodlebug".
I did, and I was amazed at how many things have been called doodlebugs -- from self-propelled rail cars, to tractors made out of old Ford cars, to unmanned flying bombs (The V-1 flying bombs used by the Germans against London during WWII were alternately referred to as Buzzbombs and Doodlebugs.) And there were even racecars from the 1930's that went by the name.
But this was a new one on me.
“Doodlebug” is the name Sgt. C. O. Peterson gave this runabout built of salvaged airplane parts. Single cylinder engine does 200 miles to the gallon at speeds up to 42 mph. The tank holds two quarts of gas and the machine weighs 300 lbs.
From Mechanix Illustrated, February 1946.
Found on the Modern Mechanix website.