Actually deploying flaps should cause the plane to balloon up, not dive. However, after the plane has reached speed equilibrium with the flaps deployed it may nose down. This is what is great about flaps! You can come down a steeper approach angle and not build up speed. The flaps/flaperons on my Airtronics VG6000 are activated by a three position switch. Position one is retracted, position two is half flaps and position three is fully deployed. With a rotary knob I would set it up so retracted is at one end of rotation and the other end is fully deployed.

As well as there being flaperons, there are also elevons, ruddervators, spoilerons and other obscure control surfaces and control surface combinations. However, flaperons have really caught on with the advent of "confuser radios" as they are so simple to employ and are very useful on our simple sport planes, as well as 3D ships.

Mark
AMA 59165