The Rose-Rice Turret
It was fitted to Lancasters of 150 Sqn for testing in 1943. It subsequently enteres service in 1 Group being used by numbers 83, 101, 153 and 170 Sqns. About 180 aircraft had them fitted. It had improved hydraullic systems and gunsights over the standard Fraser Nash turret and the stopping power of the .50 cal. However, it had considerably less ammunitin and was very cold due to the large openening in the perspex. But it was popular with it's operators as it was roomy, and was easy to escape from. The operator just had to roll out of the hole. Also, the operator could wear a back pack parachute whereas with the Fraser Nash turret, the gunner had to clip on a seat type parachute to bail out.
Fraser Nash subsequently fitted twin .50 cals to it's turrets, but these didn't enter service until after the war.
Another developement of the Fraser Nash was the 'Village Greeen' or AGLT system where a gun laying radar guided the operator.
These turrets were also fitted to 101 Sqn Lancasters. 101 got special treatment because it carried the ABC or 'Airborne Cigar' jamming system. transmitters on the aircraft transmitted either engine noise from a microphone in the cowling or 'spoofing instructions' from an extra German speaking crewmember. 101 Sqn had particularly heavy losses - partly because they flew on nearly every raid.
The AGLT was not the same as the 'Monica' rearward facing radar fitted to some British bombers. this was not too successful as the Germans developed a receiver able to home in on Monica radars.