Flaps aren't always required for take off. A few degree's of flap can reduce the take off roll but if you're not careful you can get into a stall situation much quicker. In other words easy on the elevator if you use flaps on take off. A lot of full size aircraft (warbirds) didn't use flaps for take off unless they where fully loaded. Pilots manuals for any particular aircraft can lend a lot of info there.
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