Those housing that are for making less aerodynamic drag when the gear is upp. they also work as a airbrake for landing and divebombing, in some rare occasion it has pappend that those housing in really high divingspeed they felld off. I have heard that in WW2 when there whas lot of american bomber-plane and other allies who entered the Swedish airspace cause of emergengy situation or making wrong navigation, and it has happened that in some rare occasion that some of them has made contact whit those SAAB B17, and because of it smoot look they first thought this divebomber whas a fighterplane, some of them even writed a report of this plane when they come back home that SAAB B17 is a fighterplane. This I whonder, for there whas also some P-51 Mustang and other longrange fighter who come in to Swedish airspace, if so couldent there been a encountering whit Allied figher and SAAB B17, and if so what happened then, could there been an air to air combat perhaps?