[klemchen]

Hello Mike,

thank you for your answer. I did not know there were any K-4s without MW50, although I have seen photos of unfinished K-4 fuselages with the round hatch on the port side of fuselage segment 2. Were these K-4s intended for training units? (Just like there were G-14s for training without MW50, in spite of the designation G-6/MW50 having been considered, but finally rejected, for the G-14.)
I still believe that the bottom hatch on fuselage segment 2 was to provide access to the control mechanism for the elevators, since inside on starboard of that segment there were two levers and a counterweight of that control. And on the K-4s with MW50 the mother compass had been moved rearward to segment 6, so there was no need of providing any access to the compass on segment 2.

Regards,
klemchen