And another...
Another, non-approved short take off technique was similar to others above: begin the take-off roll without flap and at 50-55mph bring in two stages. On the 140 it will bounce straight up as if on afterburner.
With no flap the aircraft accelerates faster but when you clunk in the flap the increase in lift has a dramatic effect. It has also worked on a 181 i used to have a share in.
Not sure I will try with full flap though; I avoided that because of the drag.