FodPlod,
SK4 - 28 troops? Maybe in cold weather, no armour, guns or other role kit and an effective range of next to nothing.
A lot of manufacturers use this type of blurb; yes, you can fit 28 people inside a SK, or fly for 3 hours, or carry a full DAS/armour/role fit or carry a light gun. Note the lack of the word (and) in the previous sentance. The same can be said of Merlin. The Chinook can do all of the above at the same time; not a boast, just a statement of fact that highlights the sheer performance of the beast. I was flying one of the CH47s that night and was involved with the planning. The combination of armour, wind direction/strength and high ambient temperature robbed the SK4 of a substantial chunk of its performance. I'm minded to think that to get around the route they were actually plugged in to bowsers to keep topping up to min fuel before they launched. Not a dig at the crews - blimey it was scary enough flying a Chinook that night, BZ to the CHF boys involved.
Tuc is quite correct about the original 108 Merlin buy for the FAA; the reduction to 40ish pinging frames was a large part of the arm-twisting that Westlands used to force the govt to buy the RAF the Mk3...oh, and using lots and lots of "it can lift 28 troops" style spin.