Flaps slow the plane down, allow/require you to carry more power on your landing approach (good if you have trouble getting your engines to idle well), permit you to make a steeper approach safely, and reduce your roll out on landing. Many of the aerodynamically "clean" warbirds are a bear to land without them.

Retrofit your trainer with flaperons and experiment with the changes varying degrees of flap make on the handling characteristics of a model. If you make this change, you will find that your trainer still has a lot to teach you, and you will have additional skills and reflexes to apply when you finish the Corsair.