I have found that Cessna flaps extend at a rate of about 10 degrees in 3 seconds. When flying a C150/C172 without a gated flap lever I find that starting the flaps running and counting 'one thousand, two thousand, three thousand' gives you a 10 degree extension. You can then check the indicator.
(Spelling errors corrected. RF)
Last edited by RodgerF; 7th July 2003 at 17:46.