Classic apples and cauliflower comparison. The KC-145 is an older technology aircraft that is smaller and lighter than the 767 would be in a tanker configuration so, naturally, it will have better take-off performance. Take-off performance is a small part of the overall operational cost per mile that the AF must consider. All of these things explain why the KC-145 is being replaced by the Airbus A330. The C-17 is not a tanker, it's a cargo plane.
The metric to measure in airline terms is cost per seat mile. The A330 fully loaded has a lower cost per seat mile than a fully loaded 767.
In tanker terms, the metric to measure is cost per lb of fuel offloaded. The KC-45A has a lower cost per lb of fuel offloaded than the KC-767AT IF (and it's a big 'if') both aircraft are fully loaded, fly the same distance, and offload all their available fuel.
Now, if you have a KC-45A and a KC-767AT, and you only offload 50,000 lbs of fuel at a range of 500 miles, then yes, the KC-45A costs more for that sortie. OTOH, if you need to offload 200,000 lbs of fuel at 500 miles, the KC-45A will be less expensive because it can do it in one sortie, were you need two sorties with a KC-767.
You can play games with sorties all day and make one or the other look better. The bottom line for the Air Force was that the KC-45A has the ability to deliver more fuel and more cargo, and costs were very close to the same as the KC-767.
Remember all last year everybody was talking about the $40 Billion Tanker Deal, but now that it has been tentatively awarded to Northrop Grumman/EADS, it's now a $35 Billion Tanker Deal?
The B767 is in design 15 years older than the A330. The same is for B787 and A330. Nearly no airline ordered a B767 recently except of a big order for some freighters. I presume with a big discount to keep the production line open until the Air Force order arrives.
“Smaller and lighter instantly means lower fuel costs per mile, especially with the more fuel efficient engines.”
According to the Air Force the KC-45 tanker is 6 % more fuel efficient than a KC-767. Just think of a pickup and a truck. The efficiency depends on how and what you have to deliver. Ever thought about why the Air Force bought KC-10s and not KC-737s?
Bye the way, why was the B747 such a success? It's such a big plane?
“Classic apples and cauliflower comparison. The KC-145 is an older technology aircraft that is smaller and lighter than the 767 would be in a tanker configuration so, naturally, it will have better take-off performance.”
The KC-135 has the worst performance of all strategic tanker flying. The comparison with the C-17 was due to Boeing's argument about available airfields. I was talking about the KC-45/A330 and not about the KC-135/B707. The bigger KC-45 has a better take-off performance than the KC-767.
The C17 is a cargo lifter for close battle field support. How close did you want to operate a tanker aircraft? Today the C-17 is misused for standard cargo missions a KC-45 or KC-767 would need half fuel.
Aircraft: C-17 / KC-45 / KC-767
Payload(1): 77.5 t / 69 t / 43 t
pallets(2): 18 / 32 / 19
fuel burn(3): 21.5 / 13.8 / 10.5
(1) metric ton ~ 2205 lb
(2) 463L master pallets
(3) according to Boeing's claim to be 24 % more fuel efficient and http://www.fas.org/man/dod-101/usaf/docs/afpam10-1403.htm
“[...]a former Navy pilot, said lawmakers should not put special interests ahead of national defense.”
http://www.al.com/newsflash/regional/index.ssf?/base/politics-0/1208834657304880.xml&storylist=alabamanews
I think he's right.