It starts with the last letter: the basic airframe mission type. Which is “Cargo”. In the -135’s case, there was a cargo-only no-refueling version. In many cases, if you see a short stack of letters in front of the airplane type number, that’s how it happened.
The “K” is “tanKer”. (“T” means “Trainer”.) As a prefix, that means that it’s a modification of the basic mission airframe to accommodate an additional or replacement mission. A KC-135 can carry cargo, as well as having the equipment and tankage to carry and transfer fuel for “customers”.
The KC-10 is a little weird. The Air Force never fielded a C-10 non-tanker version, so the “K” prefix doesn’t mean a modification of a pre-existing cargo bird. But it does haul cargo, so it’s still appropriate. I suppose since it was a direct adaptation of the dog-standard civilian DC-10, that may be counted as its cargo heritage, even if it never flew in DoD inventory until it was already converted to a tanker.
Besides, “KC-10” is very reminiscent of “DC-10”. Maybe someone decided they wanted a two-letter prefix ending with “C”, since they went to the trouble of assigning it a type number (-10) identical to its McDonnell-Douglas type number.
The were going to use “O” for oiler, (like Navy ships), but it had already been assigned to Observation. j/k
K could be kerosene. Tankers were introduced at about the time that jets were, (even though the old KC-97 Stratofreighter and the KB-29 and later KB-50 were four engine prop jobs. The KC-97 was built on the C-97 which was, itself, based on and used many components of the B-29.
I can’t provide citation beyond my poor memory, but I’m fairly sure it was the middle letter of “Tanker”, since that’s the strong consonant sound of the second syllable. Besides, “Kerosene” doesn’t seem a good reason, considering that JP-4 (primary jet fuel at the time this type of aircraft was developed) is only 50% kerosene, and KC-135s were refueling SR-71s and A-12s with JP-8, which has no relation to kerosene at all.
Too late to correct, but I meant JP-7. JP-8 is current mainline jet fuel, and is apparently mostly kerosene, but seriously postdates the use of “K” to designate tanker aircraft. And yes, SRs leaked JP-7 like a sieve. Probably would have leaked JP-4 or -8 as well.
Did the tankers leak it on the ground or in flight? I understand that the SR-71 stopped leaking at speed when the fuselage heated up, but perhaps the tankers could have tolerances at lower temps and not leak.
How often did the SR-71 refuel? I wasn’t aware that they did in air refueling.
That was more the fault of the aircraft than the fuel; the SR-71 was built to fit together a little loose so the parts could expand at high temperatures due to the aircraft’s speed.
MY understanding (which could be wrong, please correct me) is that once you are below mach 1 to refuel, the airstream then acts to cool things down. Above mach 1, the compressed air in front is what heats things up.
Why did SR-71s leak fuel on the ground? Wouldn’t they have used a flexible bladder for the fuel [like an F1 car] or wasn’t such a thing possible when it was designed?
Distance, and a dedicated fighter CAP between the AR tracks and the threat.
Because we can.
Also because OPSEC is a lot easier, from the B-2 operations perspective, when someone watching B-2 departures while sitting in their car in Knob Noster, MO doesn’t know whether the B-2 that just took off is an “out and back” trainer, or has 20k lbs. of ordnance onboard and is headed out to make someone’s day really, really bad.
There’s only 20 B-2s remaining after the crash in Guam. A handful of those 20 are always in scheduled heavy maintenance, modification downtime, flight test, or flying locally at WAFB for pilot training and proficiency flights.
The KC-10 was derived from the civilian DC-10-30CF. Since it is a commercial derivative aircraft, that is still maintained and flown to FAA type-certification standards, it retained the “-10” designation. The “C” in the KC-10’s designation is a happy coincidence between the Douglas Corporation’s “DC-x” naming convention for their civil airliners, and the USAF’s use of the “C” designator for cargo aircraft.
The USAF KC-10s were built as KC-10s from the start; they were never airliners first. They were also purchased outright, not leased. Not that anyone in this conversation has said those things, but someone always seems to come out of the woodwork and spew that nonsense in conversations about the -10…
Self-sealing fuel bladders date back to WWII, so the “thing” was definitely possible. The problem is airframe heating via friction. No bladder was available that could withstand that heat for multiple hours at a time… and there still isn’t. For that reason, the SR-71 was built with “wet wings” (and, technically speaking, a “wet fuselage”), just like all current airliners are built. However, due to the titanium airframe’s thermal expansion & contraction, there was no way to completely seal the tanks. A fueled SR-71 on the ground would drip from lots of places underneath, and leak even in flight, until the airframe expanded enough at speed for the skin joints to seal up.
The JP-7 fuel’s difficulty to ignite was the only thing that made extended operations of such a leaker possible.
I had a girlfriend who made friends with an RAF tanker squadron when she was vacationing in England. By coincidence, they were at the NAS (now MCAS) Miramar airshow we attended one year. Actually, there were a few coincidences that year. One of them was that they invited some people aboard, and one of them was an older man who checked a document on a bulkhead of the Vickers VC-10K aircraft. It turned out that he flew that very aircraft when it was in passenger service for South African Airlines.
Ah, now I get it.
No one in the USAF ever asked to see my camera or my phone. The threat is always there once you’re on the flightline, though. However, if there was classified in view, I didn’t take a pic. There were a few occasions during my boom operator career that something that would have been an awesome picture was not photographed, because something classified would have been in the frame. With my luck, the day I decided “Meh, no one will be able to see that flight plan/chart/______ in the picture”, would be the day the security folks decided to check cameras & phones of everyone on the flightline, and I’d end up with a security violation and loss of clearance.
I realized just now looking to post this that a more recent thread, SR-71 Blackbird, what’s that red outline on its back?, goes into the nozzle-designation in fueling quite deeply as a drift, and it might be looked at profitably here.
But to centralize the topic back here, particularly because thaae brand new KC 46 Pegasus is on-line (heh) in this thread and in the field…
This little vid was just posted of an F-35 nighttime refueling. Basically all the guidelines for orientation (discussed in the SR-71 thread) are unused, and they just turn the lights on full. Right?
Which makes me wonder about other orientation methods. I seem to remember the automated "robotic-assisted’ boom operation plan; I can’t remember if that was in a DARPA teaser or Boeing trailer for the Pegasus. It would make sense for mechanical location signaling, right?
That was done in almost total darkness while the camera is looking through what amounts to NVGs. The “bright lights” you think you see are actually real dim. From 1000 feet away you’d have no idea there were any airplanes there at all.
For a couple seconds as one aircraft backed away you can see the painted markings near the receiver port. And for all of them you can see two marker lights just ahead of the port as well as the lit interior of the port. All of which are there to aid the boomer in seeing what he’s doing and calibrating her aim.
Automated refueling goes with automated pilotless vehicles. Both of which are on-the-cusp tech.
As to the DefenseTech article, USAF always starts the ball rolling on the next generation acquisition just about the time they declare IOC on the latest one. They’re already talking now about what will replace the F-22 and F-35.
To be sure there’s usually 3 or 4 false starts before they get a program that gets funded for R&D, much less gets built. And as the General said, we always say we’re willing to by European aircraft, but Congress always has other ideas. Oh darn. Crocodile tears are shed in the name of NATO togetherness and USAF goes back to biz as usual.
But it’s not too soon for USAF to begin thinking about the next tanker after the KC-46. They’re also pretty excited about the idea of blended wing/body aircraft for an airlifter to replace the C-17. As are the civilian cargo carriers. It’s tech that’s tantalizingly almost ready to fly. It just needs a critical mass of plausible pre-orders to get some airframer and engine team to get serious with prototyping.
As LSLGuy already said, that video is filmed with a night vision device of some kind. Lighting that is not NVG-compatible will look like a road flare in NVGs, even when very dim. Since the vast majority of USAF boom refueling is currently done with the boom operator “unaided” (without NVGs or other night vision devices), there’s no need for the additional cost of NVG-compatible receiver lighting for refueling ops. That will change, however, once the KC-46 comes online with it’s remote-view refueling systems - at that point, receiver aircraft will either have NVG-compatible receiver lighting retrofitted, or flight testing will determine settings on the existing lighting that will minimize the blooming effects of non-NVG lights in a night vision device, while allowing for proper references during refueling.
Depending on your boredom level, you can go here and watch the tankers fly their patterns. Just have to do the search on the right for ‘currently airborne military aircraft’. I just counted 18 tankers but didn’t look to see if that’s global or just over the US.
j/k
