Flaps provide additional lift. If you have a heavily wing loaded warbird it is sometimes advisable to take off with some flaps. Flaps increase the amount of lift to your wing without increasing the angle of attack of your wing. If anything your wing develops more lift at a lesser angle of attack, thereby decreasing the probability of a tip stall. As the two previous writers noted, be gentle on the elevator because you can increase the angle of attack by applying too much elevator and climbing out at too steep of an angle. A friend of mine has a 40 pound PMC ME 109 and he regularly takes off with flaps applied.