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TropicBird
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Air Tanker Forward Basing Question

Thu Jul 27, 2006 12:33 am

Question.....as a part of their marketing campaign for the KC-767, Boeing likes to promote the fact that it can operate from forward airfields with runways as short as 8000' or less.

Since a larger aircraft such a 777, 340 or 747 (they can carry alot more fuel) would allow the USAF to bypass these forward bases and remove the risk of being denied access, would the need to forward base a tanker aircraft now be moot? How has the USAF managed this with the KC-135 since they need a longer runway?
 
aislepathlight
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 1:50 am

Quoting TropicBird (Thread starter):


Since a larger aircraft such a 777, 340 or 747 (they can carry alot more fuel) would allow the USAF to bypass these forward bases and remove the risk of being denied access, would the need to forward base a tanker aircraft now be moot? How has the USAF managed this with the KC-135 since they need a longer runway?

TopBoom had informed me that KC135s have the heightest fuel capacity of any propsed tankers, on missions longer than 4000nms, save the KC44 (or any crazy A380 tanker). So we arn't gonna pick up that much range and payload, unless we go with the KC44.
bleepbloop
 
dc8jet
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 1:51 am

How long a runway does a fully loaded KC-135 require?
 
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kc135topboom
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 1:58 am

The KC-135R at 323,000lbs max gross weight, needs about 8500' of runway. The KC-135E at 315,000lbs max gross weight needs about 9500' of runway.
 
TropicBird
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 2:18 am

Quoting AislepathLight (Reply 1):
So we arn't gonna pick up that much range and payload, unless we go with the KC44.

So does a KC-44A (747-8F) have that "edge" that the USAF needs more than what the KC-767 can offer?
 
aislepathlight
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 2:38 am

Quoting TropicBird (Reply 4):

So does a KC-44A (747-8F) have that "edge" that the USAF needs more than what the KC-767 can offer?

I guess you could say that.

Why can't a KC777 carry more than a KC135 on missions over 4000nm?

.....................KC135R........KC777 (I didn't know what to use, so I used 772s)
Empty Weight: 119,230 lbs...314,000lb
Max T/O: .......322,500 lbs...752,000lb
bleepbloop
 
pavlin
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 2:39 am

If they pick 767 it will be only to keep production line open. I think we have better planes avaliable today.
 
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kc135topboom
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RE: Air Tanker Forward Basing Question

Thu Jul 27, 2006 4:07 am

Quoting TropicBird (Reply 4):
So does a KC-44A (747-8F) have that "edge" that the USAF needs more than what the KC-767 can offer?

That is a question that only politicians can answer, not military planners.

Quoting AislepathLight (Reply 5):
Why can't a KC777 carry more than a KC135 on missions over 4000nm?

.....................KC135R........KC777 (I didn't know what to use, so I used 772s)
Empty Weight: 119,230 lbs...314,000lb
Max T/O: .......322,500 lbs...752,000lb

There is no question that a KC-10, KC-777, KC-30, KC-44, KC-787, or KC-340 can take off with much more fuel than the KC-135R can. All of them can offload more fuel on missions less than 4,000nm. But, all of them burn a lot more fuel per cruise hour than the KC-135R, some 2-3 times more fuel. That is why, on longer missions the KC-135R is capable of offloading more fuel than any of them, except possibly the KC-44. This is called long range refueling.

But forward basing is a totally different tactical problem. KC-135s and KC-10s are good sized airplanes to forward base, and they both have a quick response and both are fully self supporting. Both of these airplanes are mature, reliable, and easy to maintane in the forward theater. The new proposed tankers will need to match the capabilities of the KC-135 and/or KC-10 to be able to forward base them. If they cannot match these current capabilities, a large number of KC-135s will have to remain in service to allow this tactical option to continue. Both the KC-135 and KC-10 easily maintane better than a 95% mission capability rate. The new airplanes will have to match, or better that, also.
 
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Moose135
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RE: Air Tanker Forward Basing Question

Fri Jul 28, 2006 6:35 am

Quoting KC135TopBoom (Reply 3):
The KC-135R at 323,000lbs max gross weight, needs about 8500' of runway. The KC-135E at 315,000lbs max gross weight needs about 9500' of runway.

Wow, those things are sports cars  Wink We departed out of Pease one time dragging some F-4s to England in a KC-135A, 285,000lb takeoff weight, and used 11,000+ feet of runway. Talk about a long, smoky takeoff roll  Wow!
KC-135 - Passing gas and taking names!
 
PADSpot
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RE: Air Tanker Forward Basing Question

Fri Jul 28, 2006 10:30 pm

Quoting KC135TopBoom (Reply 7):
... or KC-340 can take off with much more fuel than the KC-135R can. [...] But, all of them burn a lot more fuel per cruise hour than the KC-135R, some 2-3 times more fuel.

A (potential) KC-340 would have essentially the same engines (CFM56-5C) as the KC-135 (CFM56-2B). The 5C might have one third more thrust, but they are about 10 years newer in technology. They won't need 2-3 times more fuel, but probably 30-50 percent more.

I don't now how much fuel a KC-340 could carry over what range, but in a hot/high scenario and fully laden the KC-340 would need a helluva runway ... there are better ideas around.
 
TropicBird
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RE: Air Tanker Forward Basing Question

Sat Jul 29, 2006 10:02 am

Quoting PADSpot (Reply 9):
A (potential) KC-340 would have essentially the same engines (CFM56-5C) as the KC-135 (CFM56-2B). The 5C might have one third more thrust, but they are about 10 years newer in technology. They won't need 2-3 times more fuel, but probably 30-50 percent more.

I think they had the A340-500 in mind. How would that model perform?
 
PADSpot
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RE: Air Tanker Forward Basing Question

Sat Jul 29, 2006 5:21 pm

Quoting TropicBird (Reply 10):
I think they had the A340-500 in mind. How would that model perform?

Wingspan is even larger than that of the 777 and the 777 is far more economical ...
 
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kc135topboom
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RE: Air Tanker Forward Basing Question

Sat Jul 29, 2006 6:26 pm

Quoting Moose135 (Reply 8):
Wow, those things are sports cars We departed out of Pease one time dragging some F-4s to England in a KC-135A, 285,000lb takeoff weight, and used 11,000+ feet of runway. Talk about a long, smoky takeoff roll

Been there, done that.

Quoting PADSpot (Reply 9):
A (potential) KC-340 would have essentially the same engines (CFM56-5C) as the KC-135 (CFM56-2B). The 5C might have one third more thrust, but they are about 10 years newer in technology. They won't need 2-3 times more fuel, but probably 30-50 percent more.

The CFM-56-2B engines on the KC-135R put out about 22,000lbs of thrust per engine, pushing a 322,000lb airplane. At cruise airspeed and altitude, it burns about 7500lbs of fuel per hour.

Now, should a KC-340 be built, based on the A-340-200/-300 airplane with CFM-56-5C engines, which have about 34,000lbs of thrust, you are really talking about a 650,000lb airplane, more than twice as heavy as the KC-135R, but only 48,000lbs (total) increase in thrust. This airplane would burn between 15,000lbs and 20,000lbs of fuel at cruise airspeed and altitude. Perhaps more (fuel burned per hour) because you are really talking about a wide body airplane vs. a narrow body airplane.

Quoting TropicBird (Reply 10):
I think they had the A340-500 in mind. How would that model perform?

Yes, if the USAF were to have a tanker built based on the A-340 airframe, it would (most likely) be using the A-340-500 as the basic airplane. It carries much more fuel than the A-340-300, and has bigger engines, allowing many more runway options.
 
TropicBird
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RE: Air Tanker Forward Basing Question

Sun Jul 30, 2006 12:16 am

So if the USAF wanted to go with a bigger airframe (large category) then Airbus would be hard pressed to provide a competing model as the 340-500 (340-600?) is all they have to compete against the 777 or 747.

For those who would say what about the A380, the USAF/RAND AoA study shot that down. Said it was too big so the USAF won't even consider it.

If you were Airbus what would you do then?
 
aislepathlight
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RE: Air Tanker Forward Basing Question

Sun Jul 30, 2006 1:01 am

Quoting TropicBird (Reply 13):
So if the USAF wanted to go with a bigger airframe (large category) then Airbus would be hard pressed to provide a competing model as the 340-500 (340-600?) is all they have to compete against the 777 or 747.

As I have repeatedly said, for everything Airbus brings to the table, Boeing one ups them

Quoting TropicBird (Reply 13):

If you were Airbus what would you do then?

Cut losses now, and get ready for the next competition
bleepbloop
 
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kc135topboom
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RE: Air Tanker Forward Basing Question

Sun Jul 30, 2006 2:44 pm

I doubt very much the USAF would ever consider a streched airplane for a tanker. The B-777-300ER, A-330-300, and A-340-600 are heavier and longer than the B-777-200LRF, A-330-200, or A-340-500 sisters. The longer airplanes just don't add anything to the tanker missions.

The only exception to this thought would be a tanker version of the B-747-800F(slightly longer than the current B-747-400F/ERF). This is because this airplane has a swing open nose cargo door.

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