Nick
Why does your slide show that the payload is constant over 260 NM despite burning about 2 hours of gas?
Even your companies technical specs contradict what your graph shows.
www.sikorsky.com/file/popup/1,,534,00.pdf . It quotes a Max Gross Weight of 11,861Kg and you quote a TOW of 10,441 Kg with max internal fuel. By the gift of simple mathematics, the difference between the 2 figures = 1420Kg
OR some 380 Kg less than you quote as available payload on your graph! This is indeed a marvellous Tardis like helicopter. Perhaps you should come and work for Wastelands as they could do with a new 'creative' marketing director!
Your quote of 250NM radius plus 30 Min reserve also seems fanciful since the company literature quotes max range with no reserves as 538NM. At range speed this would give you 469.5 NM range (235 NM radius) with 30 mins reserve at range and not endurance speed, but even so, it would flipping tight and is not quite the 250NM you suggest. You would also have to add on the 2.5 min per hoist op for the 20 survivors so we would now be looking at a maximum radius of action with hoisting 20 pax and 30 min reserves of about 180NM - DOH!
The 538NM Range quoted at 137kts = 3.92 hours of flying, therefore given this is to tanks dry, and your max internal fuel is 2,253Kg, this give a burn rate of about 575 Kg/hr - If this is true on an 12,000 kg aircraft, can we get those engines fitted to the CH47 as it is about 2/3 of the fuel used prorata by that beast.
Oh and by the way, the max radius of action on the Merlin will only be limited by the availability of inflight catering and a suitably equipped C130 tanker to give it some gas.
If you are going to get arsey with Crab, get your facts inline with your company's blurb - mine's a brandy by the way?
HPT