il-2's armoured cockpit could be penetrated only by 20mm. dunno about high-power UB and .5Brownings, but MG 131 almost could not harm Il-2's pilot from rear.
but the later added gunner was protected very miserably. indeed. with low power/wt ratio of AM-37/Il-2 another crewman with heavy UB seriously decreased plane's performance. but anyways, during 1942 crews made field modifications to accomodate a gunner with ShKAS, UB or even DShK.
in late october of 1942 a serial production two-seaters entered action under stalingrad. the situation improved when more powerfull AM-38F could carry two-seaters since 1943-01.
but the later added gunner was protected very miserably. indeed. with low power/wt ratio of AM-37/Il-2 another crewman with heavy UB seriously decreased plane's performance. but anyways, during 1942 crews made field modifications to accomodate a gunner with ShKAS, UB or even DShK.
in late october of 1942 a serial production two-seaters entered action under stalingrad. the situation improved when more powerfull AM-38F could carry two-seaters since 1943-01.