Note: This is not about a late war German victory scenario or even a stalemate, just a discussion of the effect of a technology appearing earlier in the war. http://en.wikipedia.org/wiki/Proximity_fuze Wikipedia has some interesting information about the German Proximity Fuse project. Apparently by the end of the war 1000 units had been successfully test fired before the project was cancelled due to the facilities being overrun. Not only that, but by Führerbefehl the project was cancelled in 1940 due to not being ready within 6 months and not restarted until 1944. Roughly within 15 months of being restarted the Germans had a functional Proximity Fuse ready for mass production. So what if the project was not cancelled in 1940 and the fuse was ready by the end of 1943 for mass deployment? I realize of course this requires some handwaving to get Hitler to change his mind and some allowance for technological developments that had occurred between 1940-1944 OTL that would have aided a quicker development of the Proximity Fuse project starting later. For that reason I had development take longer than 15 months ITTL and do require some suspension of disbelief, though I should mention the US had their VT fuses ready in 1943 and only started the project in 1940 (with some British help, having started their project in the late 1930’s), whereas the Germans had been working on theirs since the mid-1930’s. So what does this mean for the air war from late 1943 on? From historical experience the US claimed effectiveness was 3-4x greater with the Proxy Fuse. Germany also had a more experienced and effective Flak force in 1943 than the Americans. Also the German reliability for their historically tested fuses, fired at a metal wire, were 95% within the ‘kill’ range of the 88mm shell’s explosion. Also the Germans used an electrostatic sensor for their shells, unlike the US, who used radio detection, which made the German shells very difficult to jam, even for Chaff. The major problem would be directing the Flak guns to target the right piece of sky, which is where the Germans did have some trouble given the large numbers of batteries and training the right personnel for fire direction. Still with a 3-4 fold increase (US experience) in destruction, which may actually be higher in this scenario, as the US and Germans were shooting at different targets in different scenarios (US was using them against Kamakazis, while the Germans were shooting at slower, more bunched heavy bombers, which were larger targets and more vulnerable in formation flying), the Germans could very well put the Allies above the sustainable loss rate and force a stop to daylight and potentially nighttime bombing. This prevents the dispersal of German factories, prevents damage to German industry and worker, prevents the destruction of rail infrastructure, and the destruction of German synthetic oil facilities, while also preventing the mining of the Danube by air and the heavy reduction of oil imports from Romania. Also, once the fuses could be mass produced, the flakwagons of the army could have a much more effective weapon for fighting fighter-bombers that stalked and caused so much damage to the German ground forces. These could also be used for airfield defense and against Flak suppression raids by the Mosquitos, which would probably become the go-to bomber for missions, thanks to their high speeds and potential to outrun Flak concentrations. Does this prevent D-Day or at least change the ability of the Allies to breakout of Normandy? What about the use of the Proximity Fuse for artillery and to create accurate airbursts against targets that cannot be properly spotted? The fuse is also adaptable for rockets and mortar rounds too. Could the R4M and later Wasserfall rockets become that much more effective with this fuse?