[Kurfürst]

Originally Posted by Nick Beale

I'll take your word for it, although the specification was issued a year before the first Spitfire flew. The point is that the Air Ministry (or Ralph Sorley) had studied armament needs and come up with the 8 MG specification. They were thinking ahead. So the Bf 109's cannon came years later than the 8 MG specification — which was kind of my point.

My point is that they were hardly the only ones, the major difference being that while the RAF was increasing the number of guns for its fighter specifications, others were on the path of opting for cannon armament.

The March 1933 specification of the RLM - which ultimately lead to the 109 - specified either

-a single, very powerful but heavy 2cm MG C/30 Motorkanone
- two engine cowl-mounted 7.92 mm (.312 in) MG 17 machine guns, or
- one lightweight, engine-mounted 2c MG FF cannon with two 7.92 mm MG 17s.

Regardless, the competing German firms seems to have been putting with a twin cowl MG at the start (which was pretty much standard for the biplanes they replaced anyway), but the idea for heavier armament was there, from the start, and the technical aspects of the planes clearly anticipated such (see use of side mounted superchargers of the engines - this made engine mounted guns possible).

The British AM's revision for specs for gun armement (8-gun batteries) came in April 1935.The French were also adopting engine mounted cannons for the fighters at about the same time, and the Soviets were absolute pioneers of cannon armament on their I-16s AFAIK.

Also consider what was actually in service.

The eight-gun Hurricane came into service in the end of 1937, I don't know how many were in service during 1938, but I'd risk saying not many. At the start of the war there were still just about 500 produced, equipping 18 Squadrons (so roughly 2-300 being in service).

The first Spits came into service August 1938, but production was so slow they couldn't even muster a full Squadron until the end of the year, when the cannon armed 109E production started. The Emil then very rapidly started to equip units - I believe a large number of airframes were already produced, they were waiting for the Daimler-Benz engines to arrive. The Jumo powered 109D, that was the sole type employed in September 1938 (780 or so in service) was rapidly replaced by Emils by the start of the war; in July 1939, there were already some 500 Emils (and 50 of the old Doras) in service, and this roughly doubled by the end of September 1939, with some 90% of the 1125 available day fighters being the most recent type (see: http://ww2.dk/oob/statistics/se30939.htm).

In short, effectively (meaning: in meaningful numbers) cannon armed 109s and eight gun Hurricanes/Spitfires came into service at about the same time.

Wasn't the Bf 109 D in use in the Polish campaign and (as an earlier post on this thread said) the E-1 a significant element of strength in the BoB?

I believe it (the Dora) was, moreover it made up something like half the 109 force over Poland, but that force was rather small (200 or so, with the rest guarding the German air space from the West), and overall it was being phased out completely and for all practical purposes.

As for the E-1, it seems to have been produced parallel and with roughly the same production ratio as the cannon E-3 until early 1940, and made up about 35-40% of the force during BoB.

I've always wondered why this was so; there's an early war propaganda picture showing two 109Es in flight, and the leader is flying a cannon E-3 while the wingman an all-MG E-1.

I was wondering if there was some tactical doctrine behind it, stipulating that the leader responsible for the attack will be flying a heavier armed aircraft, with armament suitable against bombers, while a wingman with an armament more suitable against fighters will be protecting him..? It should be noted that it was an exception for a fighter to be armored until mid-1940, so MG armament would be still effective. IMHO it would worth looking at if JGs were equipped in such fashion, with an equal mix of E-1s and E-3s.