Mine came with holes so I did some research in deciding whether to cover the holes or not and think I remember that the Navy dive bombers had holes in their dive brakes or dive flaps not to increase drag but rather to reduce the effect of the disrupted slipstream over the tail control surfaces. Having holes also reduced weight. That's not to say the holes didn't increase drag with those Navy planes . . . I just didn't follow the question all the way to getting a definitive answer.
On mine, I don't remember ever coming to a conclusion as to whether having holes increased drag or not. I tried covering them up with packing tape to see if I could tell any difference. I couldn't, although my brake only goes down to 30 degrees or so so the brake affect is not that noticible anyway. As Mark has mentioned, using the belly board does reduce stall speed somewhat so it does generate some lift and I've noticed that too. Ineffective as mine is, I always use it. Flying Jim Morehead's KR with his excellent belly flap, I was really impressed by how much nicer approaches and landings are with a nice big drag flap. Mike KSEE ____________________________________________________________ What's your flood risk? Find flood maps, interactive tools, FAQs, and agents in your area. http://thirdpartyoffers.juno.com/TGL3141/547b6b1a308bd6b1a3591st02vuc