Gnoe, you've used an old thread to ask your question in. It would have been better to start a new one.
In short: Cd is very much influenced by frontal surface area. Have a look at a Cessna wing from straight ahead (looking at the leading edge, use a stepladder if needed to get your eyes level with the wings) with flaps up and with flaps 10 degrees down and try to see how much the frontal area has increased with just those 10 degrees. Now go to 20 degrees, 30 and 40 (if possible on that Cessna). It's the equivalent of sticking your hand out of the window of your car while driving, palm facing front.