Sorry to be pedantic, ITCZ, but fuel flow is proportional to thrust in a jet engine and power in a piston engine. As power equals thrust times speed, the power of a jet engine is zero at take-off epr when you're stationary at the threshold and then increases as you accelerate (thrust constant). In a piston however, power remains constant and therefore thrust decreases as you accelerate. (Not really related to thread topic but may be of interest to other nerds like me!)