[G.R.Morrison]

I recall hearing the old bromide about the spiral being off-putting for the gunners, but I read a pilot's comments (I CANNOT recall who it was) from much-earlier in the war, when the "Kullerschnauze" 1/3 + 2/3 segments came into common use, stating that the flickering effect was a recognition feature that worked for an aircraft in the mirror, behind you. One quick glance, and you knew it wasn't an R.A.F. fighter.

I think the spiral tends to disappear at high speeds, and the gunner is aiming at a dark, rather-small frontal aspect of the oncoming machine in any case.

The earliest spiral I recall was on Tiedmann's 2./JG 3 Bf 109E-4 WNr.1990, and the line is so fine/tight, it seems unlikely to be serving any purpose besides decorative. Rudi Müller's Bf 109F-4 WNr.10073 of 6./JG 5 was wearing a broad spiral well before they became common.

Sorry I cannot quote my source, GRM