Saying "Go like the clappers"

Can any one tell me where the saying "go like the clappers" comes from and what clappers actually are.

From the discussion forum archives under "clappers":

clappers, like the. 'Very fast, or very hard (e.g. "run like the clappers"; or "the clappers of hell").' Gerald Emanuel, letter of March 29, 1945: C. 20; since ca. 1925, much used by the R.A.F. As _clapper_ suggests _bell_, so _hell_ rhymes on _bell_: and _go like hell_ is to run very hard indeed.
From A Dictionary of Slang and Unconventional English