nope you put armour round the engine (which is impossible in a radial )
I'm not at all sure it makes any difference, since the spares would be coming from different supply chains anyhow. Unless you mean cross-AF scrounging?Since the DAF was flying a lot of Hurricanes and even some Spitfires at that point along with some number of Merlin equipped P-40s of their own ...not a bad idea for the USAAF to send a group of Merlin equipped fighters to a theater where there are already a lot of Merlin equipped fighters.
I'm not at all sure it makes any difference, since the spares would be coming from different supply chains anyhow. Unless you mean cross-AF scrounging?![]()
For further information look up George M. Chinn’s (USMC ret.) work in the 50s on ‘Machine guns’ where he is scathing about these mistakes made and time it took to correct them – summarised here by Antony Williams
Now had these issues been hand waived in a given ATL – I dunno – the British somehow push the various companies (International Harvester, Oldsmobile, and Bendix) who are making the weapon to build them to their designs and not the one supplied OTL by US Army Ordinance Engineers – then I think it is very likely that the later Mustangs that took the Air campaign to the Luftwaffe above Germany would be toting 4 x 20mm cannon or a mix of Cannon and MG and the P47s very likely carrying 4 or even 6 of them in the later varients.
57th FG was the only USAAF fighter group serving with the DAF (there were three bomber groups) and it was attached to No. 211 Group so they would have been drawing from the same supply chain as the DAF P-40s.
Honestly, all International Harvester (who, iirc, built the US Hispano as the A/N-M1, M2, and starting 43 M2C) needed to do was alter the neck dimensions in the breech. That the main difference between British and American Hispanos and it is what set the successful British Mk.V apart from the troubled US versions.Or the US could have done what the IJA did, make a bigger Browning, and call it good.
Honestly, all International Harvester (who, iirc, built the US Hispano as the A/N-M1, M2, and starting 43 M2C) needed to do was alter the neck dimensions in the breech. That the main difference between British and American Hispanos and it is what set the successful British Mk.V apart from the troubled US versions.
Up sizing the Browning (AN/M2 .50 BMG) is certainly possible and could be effective but would likely be larger (in the receiver) than the HS.404 and possibly weigh more, as well, making packaging more difficult.
Browning .50 M2 12.7x99 29kg 850rpm
Ho-5 (upscale) 20x94 37kg 850 rpm
Hispano Mk.II 20x110 50kg 600 rpm
Hispano Mk.V 20x110 42kg 750 rpm
Ho-155II (biggest Browning) 30x114 44 kg 650 rpm
rebarrel and slightly upsize that Ho-5 to 20x110, and you have a more compact gun with a faster rof
I wonder why they didn't?
The thing is the British have a working cannon - have ironed out the bugs - stopped it from freezing etc at high altitude - and have a reliable working belt feed system - so what's the point in buggering about developing a new unproven weapon system?
US weapons development was abysmal.
Besides botching the Hispano, they also wasted the whole war trying to make the MG151 work in .60 caliber, and most of the war trying to get the M2 Browning to run faster.
And then the MG-42 in 30-06 fiasco
It just doesn't seem to have occurred to them, despite capturing the Japanese examples.
And the BAR, which was a fantastic rifle design but not a very good squad automatic weapon.
I don't know if this has been suggested yet but if you want more P51s then have the orders for the Curtiss P40 canceled and Curtiss be subcontracted to build the more modern P51 in their place.
Ok, so maybe it wouldn't be heavier than the HS.404 but the installation would still be limited because of the receiver height. The .50 cal Browning receiver was already taller than the HS.404 and necessitated the gun be installed on its side to fit within the wings of some British aircraft which were originally designed only for .303's. Scaling the receiver up to fit the 20mm x 110mm cartridge would make this even worse. Plus, a Browning made to use the 20mm x 100mm would be bigger and heavier than the Japanese Ho-5 which used Japanese 20mm x 94mm rounds. Also, a good part of the weight of the Hispano was in the barrel which is considerably longer than that of the Browning Light barrel (67" vs 36"). The break down for the A/N-M2 20mm that I can find shows the receiver and breech was about 29.3 kg, the barrel about 21.5 kg, and the feed mechanism and de-linker for the belt-fed variant another 8.6 kg.Browning .50 M2 12.7x99 29kg 850rpm
Ho-5 (upscale) 20x94 37kg 850 rpm
Hispano Mk.II 20x110 50kg 600 rpm
Hispano Mk.V 20x110 42kg 750 rpm
Ho-155II (biggest Browning) 30x114 44 kg 650 rpm
rebarrel and slightly upsize that Ho-5 to 20x110, and you have a more compact gun with a faster rof
Open mouth, insert foot. Goes to show you how much I know.View attachment 356772
Spitfire Mk.XVIE. It appears to be upright.