Well... you have a good point. I think that 75 mph is pushing VNE (if not exceeeding it) for 40 deg flaps on the 150. (can we rip a flap off the plane please?)

Yes the whole point of flaps on a full scale aircraft is to be able to make a slower landing approach and still maintain control. (or at first detent.. aid in preventing tip-stall on take-off)

The normal way they deal with flaps on full scale airplanes is... add more as speed decreases... not put them down and try to hold speed.

Another use of flaps is to increase descent rate without allowing airspeed to build up. You can point the nose upward, slow down, add flaps and power to descend almost like on an elevator. The flaps add a tremendous amount of drag. The center section of the wing would be stalled and the tips would have full aileron authority.

Full flaps and some power added on my Kadet Sr... You'd think you had a Fokker Tripe's glide slope (45 deg nose-down or stall if dead stick on the Tripe) instead of the glide slope of a Kadet Sr's that wasn't using flaps (float forever). Except the Kadet with flaps has a 10 ft roll-out... the Dr1 rolls 100 ft minimum.