A 747 lacking hydraulics has been flown and landed using alternate flaps for pitch control? Really? Where and when?
The flap motors are located in the wheel wells on a 747. Even thought the larger gear doors reclose after the gear has been extended(normally), there are still big gaps for air to get into the wheel wells. "Wind-chill factor"
Under normal operation the gear doors close, but not in alternate extention, and this is, of course, a thread on loss of hydraulics and back up hydraulics. The gear doors in a situation involving loss of hydraulics would normally be open.
I haven't seen anything stipulating reduced cooling periods with the gear down; apparently Boeing didn't feel this pertinent. Point is, while you may be able to achieve some semblence of a stable descent, trying to fly the airplane around on the alternate flap motors...the ones that take five and a half minutes to move the flaps...is really more of a sim exercise than an alternate way to land the airplane.
Certainly one will try what one can...but to think of it as another way to fly the airplane or to control the airplane is a bit of a stretch.