Not for nothing was it termed the 'Belslow'.
Which, as far as max payload is concerned, is 4% more, 80% further and 60% quicker........
BEagle, the Belslow certainly wasn’t fast, and I laughed out loud at your comment concerning the mach meter, but I think you’re comparing max cruise speed on the A400M with long range cruise speed on the Belfast, so the difference isn’t quite as great as you suggest.
If Wikipedia is to be believed, cruise speed on the Belfast was 358mph, but my Putnam’s “Aircraft of the Royal Air Force” says that long range cruise was 315mph (same as your figure) and max cruise was 346mph. You’re quite correct however to point to a significant speed and range advantage in favour of the A400M. Is that enough to justify the huge increases in empty weight and fuel consumption though?
If (hypothetically of course) FBW controls, composite materials, digital electronics, some aerodynamic improvements and improved engines were applied to a Belfast, I’d have thought that the weight savings and improved efficiency would allow it equal the A400M’s payload/range (but not the speed). Why then is the empty weight of the A400M 11 tonnes more than the Belfast and it's fuel consumption 39.3% higher? Is the A400M an ambitious enough / efficient enough design?
Many future airlift needs will require ranges, payloads and speeds beyond the capability of the A400M. Wouldn’t it be better to buy the C5 (if production could be restarted), C17, A380 or B747 for sectors where speed, range and payload are more important than tactical capability, and then shorter range tactical transports to move cargo from there to the forward operating base where countermeasures, short/rough field performance, manoeuvrability, airdrop capability, turnaround time etc are priorities? This would be a logical specialisation in terms of both aircraft and aircrew capabilities.