Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Max Q wrote:If Airbus has truly perfected automated air refueling then surely this is the answer and a significant advance
Could we see the boom operators position vanish completely?
Max Q wrote:If Airbus has truly perfected automated air refueling then surely this is the answer and a significant advance
Could we see the boom operators position vanish completely?
ThePointblank wrote:Max Q wrote:If Airbus has truly perfected automated air refueling then surely this is the answer and a significant advance
Could we see the boom operators position vanish completely?
No, because someone has to monitor the connection, manage fuel flow, and take over in case of an emergency.
Grizzly410 wrote:Sure the system could be portable to KC-46, but that would probably request way to much integration work. At this point Boeing is better of squeezing its supplier to make the existing work !
WIederling wrote:Grizzly410 wrote:Sure the system could be portable to KC-46, but that would probably request way to much integration work. At this point Boeing is better of squeezing its supplier to make the existing work !
You can't squeeze an empty zit
The mentioned application range would imho indicate that installation/integration on KC46 would be low hanging fruit. ( put the sour grapes in the trash.)
Grizzly410 wrote:I’m afraid such a change would only provide some certainty using a proven system, but time and money wise I’m not so sure about this being a good idea at all.
Grizzly410 wrote:ThePointblank wrote:Max Q wrote:If Airbus has truly perfected automated air refueling then surely this is the answer and a significant advance
Could we see the boom operators position vanish completely?
No, because someone has to monitor the connection, manage fuel flow, and take over in case of an emergency.
Even if I don't know how AAR are operated in general, and only the nominal way of working of the A3R I can assure you Airbus Defense&Space goal is very much to get rid of the boom operator. A3R is only a first step to achieve this.
LyleLanley wrote:
If the KC-46 has taught the AF anything, it's that there's a huge gulf between what the contractor promises and what is actually delivered.
747classic wrote:...
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744SPX wrote:I completely understand using the 767 airframe, but it still blows my mind that they are using a nearly 40 year old engine design when this thing is supposed to be flying for the next 50 years. Never understood the decision to drop the blended winglets either (from the previous competition). I realize fuel economy isn't a concern for the AF, but this makes it look like they are trying to burn as much fuel as they possibly can.
747classic wrote:The GE CF6-80C2 would have been the real low risk solution, because this engine is by far the preferred engine at civil 767's and was already installed at the Italian and Japanese 767 tankers.
Seen all the time consuming issues with the WARPS - wing flutter on these aircraft, why choosing another engine type and another warp manufacturor, with a different flow pattern and weight causing the same difficult to solve problems. (nor solved yet, after how many years)
The lobby of PW must have been very strong to get this engine at the KC-46A.
LyleLanley wrote:Max Q wrote:
Well, there’s no room for an ARO station until you design it in and build it
It could have been done
Sorry, I should have been more specific: there's no room for an ARO station AND the required gas. To say nothing of the centerline drogue or the LAIRCM pod on the belly. The 46 is volume-limited and the RARO station was seen as the best way to mitigate that deficiency.
LMP737 wrote:747classic wrote:The GE CF6-80C2 would have been the real low risk solution, because this engine is by far the preferred engine at civil 767's and was already installed at the Italian and Japanese 767 tankers.
Seen all the time consuming issues with the WARPS - wing flutter on these aircraft, why choosing another engine type and another warp manufacturor, with a different flow pattern and weight causing the same difficult to solve problems. (nor solved yet, after how many years)
The lobby of PW must have been very strong to get this engine at the KC-46A.
I believe it's the result of PW underbidding GE.
kitplane01 wrote:I don't understand this. The photos I've seen of the KC-46 show a clear interior ready for cargo, and not a fill-every-space gas tank.
LyleLanley wrote:Maybe more if some of the KC-10 design/test experience were still in the company.
LyleLanley wrote:Maybe more if some of the KC-10 design/test experience were still in the company.
ssteve wrote:It's been quite a few decades. It's amazing what organizations will forget over those years, especially when the last go-round didn't use CAD. Old ideas get rediscovered and old mistakes get repeated.
747classic wrote:
The cheapest option is most of time not the best option, but in this case it could have been (USAF) politics ?
LMP737 wrote:747classic wrote:
The cheapest option is most of time not the best option, but in this case it could have been (USAF) politics ?
The PW4000 series are proven motors, probably going to be one of the most reliable pieces of equipment on that aircraft.
texl1649 wrote:At a certain point, I wonder if Boeing will consider scrapping the current system and installing something from someone else for USAF. I don’t see any way to salvage the current one to meet all requirements/standards USAF is holding them to.
zeke wrote:texl1649 wrote:At a certain point, I wonder if Boeing will consider scrapping the current system and installing something from someone else for USAF. I don’t see any way to salvage the current one to meet all requirements/standards USAF is holding them to.
Why would the USAF go back to the vendor who could not supply the system that was originally contracted, why not just get the vendor with the product that works to perform the work directly. Adding Boeing into the picture would add not value to the process at all, just additional red tape and cost.
747classic wrote:
That's may be true, but seen all the development/ flight testing performed already at the 767-200/CF6-80C2 with warps it's not the most cost effective solution.
On top of that, most civil 767's are powered by GE engines, the second preffered engine type is P&W and the few RR powered 767 aircraft are destined to be scrapped soon.
LMP737 wrote:747classic wrote:
That's may be true, but seen all the development/ flight testing performed already at the 767-200/CF6-80C2 with warps it's not the most cost effective solution.
On top of that, most civil 767's are powered by GE engines, the second preffered engine type is P&W and the few RR powered 767 aircraft are destined to be scrapped soon.
You agree that the PW4000 series of motors are a proven design. Do you have any evidence that shows that it's not the cost effective to have the Pratt motors on other than there are more GE powered 767 flying?
747classic wrote:LMP737 wrote:747classic wrote:
That's may be true, but seen all the development/ flight testing performed already at the 767-200/CF6-80C2 with warps it's not the most cost effective solution.
On top of that, most civil 767's are powered by GE engines, the second preffered engine type is P&W and the few RR powered 767 aircraft are destined to be scrapped soon.
You agree that the PW4000 series of motors are a proven design. Do you have any evidence that shows that it's not the cost effective to have the Pratt motors on other than there are more GE powered 767 flying?
The PW4000 is also a proven design, but not the preferred option on the 767 series, on top of that : all late built civil 767's are powered by GE engines.
More important however :
The interaction on the KC767A between the GE CF6-80C2 engine, the 767-200 fuselage plus wing platform and the WARP's were finally resolved after many, many test flight hours and re-designs, delaying the KC767A delivery for more than a year.
Why choose a new engine type (weight en arerodynamics differ) and a new WARP design for the KC-46A, requiring a lot of extra testing to understand the flutter modes with and without WARP's installed.
IMHO the USAF selected the PW4000 only at costs/hour and under-estimated that the integration of this engine into the KC-46A with WARP's had to be certified again and would require a lot of (flight ) tests again.- no lessons learnt from the past.
At this moment the WARP's are still not FAA certified (why FAA certify a military refuleing pod by the FAA ??) and operational and will need a lot of additional (flight) testing to understand the flutter modes with another engine type (PW4062) installed.
If the GE engine had been selected a lot of these very expensive WARP flutter flight test, that finally are in progress now (see link below), could have been avoided.
See Matt Cawby's Paine Field blog of Feb 20th : http://kpae.blogspot.com/2020/02/paine- ... ry-20.html
And : http://www.paineairport.com/kpae18820a.htm
ThePointblank wrote:The WARP's on the KC-767 and KC-46 are not identical.
The KC-767's WARP's were made by Smiths Aerospace and are no longer manufactured.
The KC-46's WARP's are made by Cobham.
They are both different units with different flow characteristics.
JayinKitsap wrote:Boeing in their proposal for the RFP had already selected the PW's. Why, I don't know, but this GE vs PW debate was going on all during the RFP period and selection. I thought they should have done the GEnX but at that time it didn't have years of in flight experience for reliability. I don't think the USAF was able to select the engine.
scbriml wrote:...I think Boeing put out an RFP for engines for their proposed tanker and selected the cheapest. They had to keep costs as low as possible. Offering an engine that wasn’t even certified on the 767 would have been hugely expensive and likely lost them the competition.
LyleLanley wrote:kitplane01 wrote:I don't understand this. The photos I've seen of the KC-46 show a clear interior ready for cargo, and not a fill-every-space gas tank.
I could've written that better as "the KC-46 is volume-limited underneath its cargo floor". If Boeing fitted a conventional (window) ARO station to the KC-46 it would have to be underneath the cargo floor, due to the geometry of the fuselage and the practicality of the window installation. Unfortunately, in order to fulfill contractual obligations for amount of fuel to be offloaded as well as have them be accessible for field repairs and still have a decently aft CG for fuel burn, Boeing had to fill every nook and cranny of the aft underfloor with fuel tanks. This meant no room for a conventional ARO station. There's plenty of room in the forward cabin for a Remote ARO station (RARO), but no room down below in the aft section for an ARO station. In the end, the KC-45 was superior in every manner except ramp space/infrastructure: it's nearly the size of a KC-10 whereas the KC-46 is much closer in size to the KC-135 so it's more apt to be "plug and play" with the hangars/ramp space the KC-135 uses. The price you pay with a smaller tanker, though, is that everything has to fit in a much smaller volume. Boeing couldn't do it with an ARO station.
Re: the points you bring up, you can't really zoom with the cameras they have installed. It's just not practical. #2 also aren't issues. CRM will be the same whether in the very back or the forward cabin, but there's still a door separating the operators from the pilots, i.e. they're all communicating via interphone. It's not any safer and egress is a non-starter in a jet with no parachutes/useable exits. #1 and 3 are pretty much spot-on, though, and are the reasons why Boeing went with RARO. Unfortunately, they started with #3 and went cheap with #1.
Cheap, quick, good. You can have 2/3, and Boeing even screwed up the 2nd.
kc135topboom wrote:Actually the body fuel tanks in the KC-46 are smaller than those in the KC-135, holding less capacity of fuel, and the aft cargo compartment could have been used for a Boom Pod, similar to the KC-10 Boom Pod.
The KC-46A carries just slightly more fuel than the KC-135R.
The KC-45 is a lot bigger than the KC-10, in fact the KC-45 would have been the second largest airplane in the USAF, by wing span, behind the C-5. The A-330 wingspan is bigger than the current VC-25A, but not the future VC-25B. Since the USAF would have bought 179 KC-45As, that would have required a huge investment in infrastructure and ramp space.
Cameras have an inherent flaw in the fast the lens needs to be mounted on the outside of the airplane and along the bottom and lower fuselage sides. These areas tend get dirty in flight, not to mention minor fluid leaks that run along the sides and bottom of the airplane. All airplanes eventually leak. This contaminates the camera lens inflight when it is impossible to clean the lens. I've never had this problem using the Mk. 1 eyeball and a window.
P.S. the P&W engines were selected to keep the price low, that is also why the KC-46A does not have thrust-reversers.
LyleLanley wrote:
We'll have to agree to disagree on the TRs.
Ozair wrote:LyleLanley wrote:
We'll have to agree to disagree on the TRs.
If you had the time to read previous KC-46 threads on TRs you would see we have been over this multiple times.
The USAF did not require thrust reversers for the KC-46 as part of the requirement set, it was not a cost savings exercise by Boeing, it was an acknowledgement by the USAF that they don’t want them. Similar to the TRs being removed by the USAF for the CFM56 as used by the KC-135R.
kc135topboom wrote:
Cameras have an inherent flaw in the fast the lens needs to be mounted on the outside of the airplane and along the bottom and lower fuselage sides. These areas tend get dirty in flight, not to mention minor fluid leaks that run along the sides and bottom of the airplane. All airplanes eventually leak. This contaminates the camera lens inflight when it is impossible to clean the lens. I've never had this problem using the Mk. 1 eyeball and a window.
kc135topboom wrote:P.S. the P&W engines were selected to keep the price low, that is also why the KC-46A does not have thrust-reversers.
LyleLanley wrote:I get that the TRs weren't an AF requirement, but that doesn't mean Boeing had to delete them. It simply meant it was contractor discretion to include them or not. My contention is that Boeing deleted them because they were in a bind as the KC-46 empty weight was steadily increasing (redundant wiring, fuel-tank inerting, armor, etc.) and saw the TRs as low-hanging fruit. When the AF and Boeing hashed out the details, the AF agreed with Boeing that they weren't a requirement and, hence, not needed. If Boeing had kept the TRs, the AF would've been fine with that, too, so long as they met all the contractual requirements.
LyleLanley wrote:Fun fact: TRs weren't a requirement for the KC-10 Extender, either. McD kept them because it was cheaper to keep them on than to take them off and they had enough weight margin to leave them. They also weren't originally going to be crewed with an FE... A more experienced/trained boom operator would've taken over the role of the FE.
Ozair wrote:I understand what you’re suggesting and agree but I’d like the think that in evaluating the proposal that the USAF would have considered the long term sustainment of a platform with TRs and one without. While TRs would play only a small part in that overall cost picture every little bit helps right.
Additionally my understanding was the brakes were so much better today than 30,40,50 years ago that they have more than compensated for the loss of TRs on the respective tanker fleet.
Ozair wrote:Ha, FEs like Navs are a dying breed. Way too many old timer Navs clogging up higher RAAF ranks although not sure what a lot of Air Forces will do once the pilots are removed. How long till the first major air force is lead by someone whose only hours are in remote vehicles?
Ozair wrote:LyleLanley wrote:I get that the TRs weren't an AF requirement, but that doesn't mean Boeing had to delete them. It simply meant it was contractor discretion to include them or not. My contention is that Boeing deleted them because they were in a bind as the KC-46 empty weight was steadily increasing (redundant wiring, fuel-tank inerting, armor, etc.) and saw the TRs as low-hanging fruit. When the AF and Boeing hashed out the details, the AF agreed with Boeing that they weren't a requirement and, hence, not needed. If Boeing had kept the TRs, the AF would've been fine with that, too, so long as they met all the contractual requirements.
I understand what you’re suggesting and agree but I’d like the think that in evaluating the proposal that the USAF would have considered the long term sustainment of a platform with TRs and one without. While TRs would play only a small part in that overall cost picture every little bit helps right.
Additionally my understanding was the brakes were so much better today than 30,40,50 years ago that they have more than compensated for the loss of TRs on the respective tanker fleet.LyleLanley wrote:
747classic wrote:I don't want to rake up the TR discussion again but saying that better brakes can compensate for the loss of TR's is only valid in perfect braking conditions. On (short) runways with braking action less than good, i always prefer additional TR's, because even super-brakes don't work with a very low friction between the tyres and runway
Stitch wrote:747classic wrote:To be fair, most major USAF bases have very long runways as the tankers need a fair bit of tarmac to get off the ground when at MTOW per a study I looked at...
kitplane01 wrote:Less weight, less maintenance, more reliability, less purchase price, and (as long as the Air Force does not use icy runways) no problems.
bikerthai wrote:By the way, news has it that they finally have a solution for the camera system that will make the Air Force happy.
bt
bikerthai wrote:kitplane01 wrote:Less weight, less maintenance, more reliability, less purchase price, and (as long as the Air Force does not use icy runways) no problems.
Or for the price of one set of TR cascades, blocker doors, and actuators, you can pay the cost of keeping one runway deiced for a decade![]()
I'm talking about the deicing solution and not the trucks![]()
By the way, news has it that they finally have a solution for the camera system that will make the Air Force happy.
bt
kc135topboom wrote:Any details about the camera fix on the KC-46A?
After a lot of study, the Air Force has learned that operator age, gender and pupillary distance can all affect how well the system works. Now they are measuring many more factors to ensure that the RVS represents the 3D reality that exists outside the aircraft, he said.
“Things are a lot better when you have technical people leading. You get to agreements faster. So I’m excited for the future of the program as long as scientists and engineers continue to lead,” he said. “I wish I could say more. We’re still negotiating with Boeing . But we’re making progress, and we’re trending in the right direction.”
The Air Force now believes a correction for the Boeing KC-46 tanker’s major technical problem won’t be available until at least 2023, forecasting a one-year delay to previous estimates, its top general said Tuesday.
The service is now targeting a 2023-2024 timeframe to begin fielding a fix for the Remote Vision System, Air Force Chief of Staff Gen. Dave Goldfein said during a Senate Armed Services Committee hearing. The RVS, manufactured by Rockwell Collins, is a series of cameras that allows users to steer a refueling boom into the aircraft receiving gas.
The slow pace of a fix prompted concerns from senators, who indicated that Congress may use the yearly defense policy bill to further pressure Boeing to move quickly.
The new timeline is an effectively a one-year delay from the three to four year timeframe anticipated for a fix in 2019, which would have put a resolution in 2022-2023. Boeing is already delivering KC-46s to the service, and it could take even longer than the projected 2023 start date to begin retrofitting the KC-46s in its possession with new hardware and software, Goldfein added.
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