A tanker thread

[FastCargo]

There are fundamental design philosophy differences between Airbus and Boeing. IMHO, the quality, durability and product support of a Boeing product beats Airbus hands down.

I can vouch for the durability aspect here at FedEx. Talking to the chief of the engineering shop at FedEx (not MX, I'm talking about the guys that come up and approve with ERs as needed, integrate new systems, basically write the MX manual) was interesting. Cargo aircraft have 'beams' that support the weight of the cargo and are hard to replace...sounds almost equal to the main wing spar in terms of importance to the main cargo floor.

Amount of beams broken over the same period of time at FedEx:

727s - None
DC-10/MD-11 - Five
A300/310s - Over 100+

I thought that was interesting...and a testament to Boeing durability.

My .02.

FastCargo

 

[FastCargo]

Duplicate post - deleted.

 

[JFReservist]

Ramp Freeze -

Thanks for the thoughtful answer, but as far as the 50K offloads...

Most of the operational offloads that I have done have required anywhere from 80 to 120K of gas, usually to a single receiver either entering or exiting their respective destination. Although it might ensure a near MGW landing, it provides them with enough gas to get off the ground quickly and not have to upload fuel in a crappy neighborhood. This also provides some relief for the ground pounders - one less convoy through IED freeway. As far as hitting the pointy nose dudes... even if we're only giving 15K to a bigger fighter, there's probably a four ship to suckle and it'll take us a few hours to get on station and a few hours to loiter then the return leg home. You're easily back up to having a great need for gas. Then there are the other missions that have been put on the shelf that might require a very big offload after a very loooong flight... we don't know how far away our enemies are going to be when we need to hit them fast.
The 737-8/900 might be able to do those things, but I don't know how much gas they can hold/offload or burn.

 

[RampFreeze]

What I was thinking about was more of the fighter orbits. i.e. take off from a base in u-pick-a-stan (or in the old days Saudi Arabia, southern Europe, etc.) and provide gas for the fighter packages. The bombers and the airlift offloads are always going require a bigger airframe. It would be interesting to look at all of the in-flight fuel issue receipts at AMC from operational missions and see what the average offloads are. I honestly don't know the answer, but it might shed some light on whether a smaller tanker is feasible for part of the fleet or not. Quite possibly not...

 

[TankerDriver]

50k of fuel on operationals?? HAHAHAH! Out in the desert this past winter we were taking off with 185k fuel loads and offloading somewhere around 85-100k. 50k will not get the job done.

The problem with a two engine jet is that in the KC-135, we run takeoff data based on 3 engines. With a two engined jet, we're talking about basing numbers off 1 engine. I just can't see anything out there right now with 2 engines, besides maybe the B777, that will be able to carry as much fuel as the 135 does with a similar footprint and be able to lose 50% of its thrust.

We need a new 135. It'd be nice to get a purpose built 4 engine jet similar to the 135 made from more composites, rewired from nose to tail with a B777 or similar cockpit. 4 CFM56's is plenty. It's quite fun getting off the ground in 4500 feet using 70% thrust with an 80k fuel load.

 

[angry tanker]

I agree with Ramp Freeze. You really need two different tankers. The one that goes to the fighter base, uploads all mx people and cargo, and then single ship drags the fighters over to base x (747/777). For conflicts, the problem is never the airborne gas, but the # of booms and cycle time. A 737 would work, but you would need to make the upstairs a tank also. I am sure our friends at Boeing have a design for that. Having an 80K offload and a 4 Hr loiter should work. Yes, this may mean being closer to the front line and having to launch a two ship to offload a heavy going in or out, but that just makes the planners have to rethink their plans (no more afr, more alert?).

Of course all of this talk is silly. Even when we had the stab trim problem on the 135s that should have grounded all them, we just had to hand fly it and hope for the best. We really need the F-22 of F-35...

 

[RampFreeze]

All transport category aircraft run their takeoff data based on the loss of an engine at the worst moment. Any current 2-engine product has the required performance for an equivalent weight. (Remember, stopping is a critical element of this, an area where the current -135 doesn’t do really well, especially due to the high runway speeds required because of it’s 1950’s wing design) If 2-engine airframes of an equivalent weight class really suffered from a performp;ance issue, you’d see a lot more 4-engine airplanes rolling off of the line today. Performance is important to the airlines too…

The 767-200ER has an empty weight about 40,000 lbs more than a -135 and a max takeoff weight about 60,000 lbs more than a -135. Wingspan and length are about 25' more than a -135. So, while it is slightly larger, it is in the same class and would be a good replacement, even though it is based on a 1983 design.

The 777 is 70’ longer than the -135 in length and wingspan, and that will impact the number of suitable airfields you can use, ramps, etc. As much as I like the 777, it really isn’t the right plane to replace the -135. It’s bigger than a KC-10. You’d have to buy a lot fewer of them, have fewer booms in the air and would be airfield limited.

-135 Carbon airframe derivative is a nice idea, but the 1950s design is WAY out of date. (Better wings, environmental, flight controls, etc. etc.) We need tankers now, not after another 10 years of R&D, design and tooling up a whole new assembly line. Buying a current product is the answer.

50K is an arbitrary number for the 737, I have no idea whether it is accurate or not for a 737-type, but it seems about right. TankerDriver, your large offload experience may not be indicative of the overall requirement. (maybe it is though, I honestly don’t know…) I remember taking off with large fuel loads and offloading it all, but I also remember taking off with 160K+, offloading well less than 40K and having to dump fuel in order to land the jet in time and turn it to the next mission. How many pounds of gas were dumped the first night of DESERT STORM? Maybe we are smarter now and plan better but maybe there is a niche for a number of smaller tankers that can cycle more groups of fighters at once. Maybe the niche capability is not worth it when compared to the economy of scale of buying more of a single type of airframe. (i.e. the Southwest airlines model) I don’t know, but it probably is worth looking at.

 

[TankerDriver]

I agree that we need tankers now, but whether we go with a proven transport airframe like the 767 or we get a new design, I still don't think we'll see a new tanker inside of 15 years due to the bureaucracy it takes to get something like this rolling. They've already said we'll be using -135's for at least another 30 years, unfortunately. They are wasting millions on upgrades to the -135 (Block 40/40.2 and the up coming Block 45 and 50 they've talked about).

As far as offloads go, current ops in the desert are to take as much as we can with given temps. Usually 160's in the summer time at 130 degrees F and 185's in the winter at 80 degrees. With a scheduled offload, we were consistantly leaving the AOR at bingo fuel. It's about a 1+45 to 2+15 truck each way from the base depending on where we go over country. Average fuel burns are about 10k/hr per mission (whats the average fuel burn per hour for the -767?). I haven't had to dump gas yet and I've been on 63 combat missions with 160k+ fuel loads. I'm not saying it doesn't happen, because it does. Whether because of an emergency requiring an RTB shortly after takeoff or canceled receivers (rare), it does happen, but how often? Not so much.

Of course, when this war is all said and done, what will our tanker requirements be? Who knows. If we can use a -767 and offload the same amount of fuel and burn less, I'm all for it, but considering us tanker toads are deployed 200+ days a year with half to two thirds of our birds from super tanker bases across the US, we don't need a tanker that can't offload the same numbers. We'll just be gone 365 days a year. Might as well PCS to the desert! Or, we could start using KC-10's more.

 

[CobraKai]

More booms in theater is what is needed. Biggest problems with all MAF airframes TDY wise are manning numbers based on coldwar theory. Tanker manning per jet is still based on 1/3 of the crews on alert, 1/3 training/crew rest for alert, 1/3 training/TDY. 2/3 or more of the time you are home. Tha PTB have no problem with increased ops tempo because they did not have to do it, or don't realize what is going on. Many a wing commander (read fighter pilot, at a base w/ mostly tankers and -130s) has come through tanker ops at base X in the AOR and said "you guys are out here how often?" or Capt X didn't you just leave here last month. Those are the same guys moving to AF level leadership. (woops way off subject) The tanker/transport will not be doing alot of airland when the war is going because they will be offloading gas in theater. once you get out to 8 hours (without force extending) the offload capability of the -135 or -10 is pretty much the same (fuel burn rates). I am for the 787 slightly wider than the 767 more efficient engines longer range = larger offload capability. One other idea I heard (but too late for this) 757 and 767s at the same base. Both are the same type rating, if you need the -135 equivlent take the 757 something bigger take the 767 same cres for both aircraft.