gun synchronization to fire through propeller arc

[Harri Pihl]

Finnish experience on wing vs fuelage guns appear to be rather contradictory. One of the first Fokker D.21s (FR-76) was ordered with 20mm Oerlikon canons mounted on gondolas below the wing. The installation was unsuccesfull, pilots reported poor accuracy, apparently the wooden wing was too flexible. However, later Fokkers with P&W Wasp Junior had only the wing guns (4x 7,7mm Browning).

The Myrsky had four fuselage guns (LKk 42 12,7mm) and the Pyörremyrsky as well as VL Humu had only the fuselage guns (all these featured wooden wing...). Also many war time pilots avdocated for fuselage guns; Juutilainen as example thought that inertia caused by wing guns is a bad thing.

One of the most succesful wartime weapon upgrades in Finland was wing gun related; the wing guns of the Brewster (Colt MG53) were replaced with the LKk 42. The LKk 42 had about twice higher rate of fire than the Colt and in the wing the LKk 42 could exploit this advantage fully because no synchronization was needed so the end result was about 50% higher firepower than before the upgrade.

Anyway, I agree pretty much with Graham; wing gun installations, even relatively weak, proved to be succesfull so apparently other factors are more important than location of the guns in the plane.