Aviate 1138
The BBMF MkV has a later Merlin fitted along with a four bladed Rotol propellor. No original production MkV aircraft had four bladers but some later aircraft did have the twelve ejector exhaust stubs. These angled stubs contributed an extra 7 mph at full power due to jet propulsion effect on the Mk9!
The early fish tailed exhaust system was nothing to do with flame damping for night flying. No damping of any kind was ever fitted to the spit. Night fighter Hurricanes with the same exhaust system were fitted with two glare shields on either side of the cowling.