I often wonder: Would it have been possible to integrate the MG151 into the wings instead of pods and how much aerodynamically better would such an installation be?
It was certainly possible - the 109K heavy fighter variants (ie. K-6) integrated a pair of MK 108s into the leading edge of the wing, with 45 rounds per gun. Alternatively, MG 151/20 installation was possible in the same place, with 100 rpg. Post war, the Spanish integrated a 20 mm French Hispano cannon into the wing of the 109G:
Aerodynamically speaking, integrating the guns into wings would yield only limited gains in drag.
The gondola armament in the 109F-K came with a speed loss of -8 km/h (at SL, at around 520 km/h). The speed loss would be a bit greater of course for later, faster variants, ie. the G-14's top speed (w/o gondolas about 570 km/h at SL) loss was about 10 km/h, and the speed loss would be a bit higher on the 109K with top speed at SL at around 600 km/h, say, 12 km/h. The top speed loss would be about 50% greater at rated altitude of ca 7000m. In comparison the difference between the K-4 and the K-6 (the latter as noted with wing MK 108) was about 5 km/h at SL, and 10 km/h at rated altitude. In short we are talking about a very modest speed gain, in the order of 8 km/h, if integral wing guns were to be adopted.
As far as weight goes, there was no difference between the MG 151/20 gondola weapons, and the wing installation of a pair of MG 151/20s in the FW 190A. The weight of the two was almost exactly the same, the difference being a few kilograms.
NZTyphoon said:
30,573 109s were built in Germany 1938-'45, the rest were built post-war by other countries
Total production up to and including March 1945 was 33 984 Bf 109s. An unknown number, about 500-1000 were still produced in April 1945. This includes the 309 produced in Győr, Hungary (I believe the actual number of Győrs production was twice as high, so this may only include the ones handed over to the LW according to the license agreement), the rest were in German factories, principially by three main factories of Messerschmitt AG at Regensburg, W.N.F. in Wienerneustadt, and Erla Maschinenwerke in Leipzig. 1860 of these were produced before 1939. The post war production was in fact quite marginal, a couple of dozen in both Spain and by the Czech, and let us recall that the Spanish 'production' was in effect just fitting and modifying the existing Bf 109G-2 airframes they received from German production, sans engines, guns and other equipment.