Hello everybody. I'm trying to finish a trio of Roden's 1/72 Camels. The kits come with two propellers, a conventional 'sabre' bladed one (part 32) and an optional one with squarer tips (33). Does anybody know when the squarer version would have been used? All photos I can find have sabre blades. Was it for a particular engine?
Sprue shot below. The optional propeller is centre bottom:

Thanks
John