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More KC-46A woes....

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More KC-46A woes....

Old 18th Aug 2015, 15:57
  #321 (permalink)  
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What have they been saying about the risks of concurrent production........

First flight of Air Force tanker test plane delayed about a month

......The flight-test schedule is already very compressed due to earlier delays.

A key program milestone previously scheduled for this month was already pushed out to next spring, as late as April. It’s the Pentagon’s formal go-ahead for Boeing to build production tankers, which comes only after the company has successfully demonstrated the required refueling capabilities during flight tests. Now Boeing will have one less month to get the flight-test results it needs for that formal approval.

In the meantime, because it cannot meet the end delivery target any other way, Boeing has begun building the first production tankers even before the first KC-46 test flight, much less the formal Air Force go-ahead.bThat, of course, introduces risk.

If flight tests turn up issues that require design adjustments, any already built tankers will have to be retrofitted, which is much slower and more costly than doing modifications during the initial assembly process................

---------------------------------------------

On the upside, they see to have avoided any flutter issues.

Boeing completes KC-46 flight flutter tests

The Boeing KC-46 Pegasus aerial refuelling aircraft test programme has successfully completed flight flutter tests on EMD 1 aircraft, marking the conclusion of an integral part of the certification process. Flutter testing is a prime requisite for aircraft capabilities testing that ensures the design of the new aircraft is structurally sound.

The completion of this testing will result in an expanded flight envelope and the ability to safely put more crew on board for further testing. In addition, the testing included the wing aerial refuelling pods (WARP) and a stowed refuelling boom.......
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Old 18th Aug 2015, 16:32
  #322 (permalink)  
 
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If flight tests turn up issues that require design adjustments, any already built tankers will have to be retrofitted, which is much slower and more costly than doing modifications during the initial assembly process................
Indeed. And this has bit Boeing badly on the 787 program. Of the fleet of flight test aircraft, only one has been successfully refurbished for delivery. And that took so long and was so expensive that no others have been refurbished. And the next dozen or more airframes after that (the "terrible teens"') are sitting in Everett without engines and (at least so far) without prospective buyers because they don't know what it is going to take to certify them for delivery. And even if change incorp and certification is accomplished, they will never have the performance of the later airplanes and because of their uniqueness, the buyers will always have support/maintenance issues with them.
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Old 18th Aug 2015, 18:13
  #323 (permalink)  
 
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787 Tankers

If Boeing was a UK company, if the MoD saw a number of of early 787s with no prospective purchasers, no doubt at one point they would have thought of converting them into tankers. Pity about the battery problems.

At least in the US this is unlikely.
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Old 18th Aug 2015, 18:20
  #324 (permalink)  
 
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At least in the US this is unlikely.
With the 767 based KC-46 program already underway, that would seem essentially impossible. But I'll bet that if the UK MoD expressed an interest, Boeing would be glad to unload the terrible teens for a very attractive price.
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Old 18th Aug 2015, 19:22
  #325 (permalink)  
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Not sure why, perhaps making holes in the back of the composite fuselage or the wing structure - but when asked why the 767 airframe was selected over 787 as a tanker - a Boeing rep stated that the 787 airframe was fundamentally unsuitable to be converted to a tanker. And with plenty of other Boeing and Airbus airframes with tanker pedigrees, I can't see any use for them except as BBJs.
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Old 18th Aug 2015, 19:46
  #326 (permalink)  
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ORAC wrote:
...a Boeing rep stated that the 787 airframe was fundamentally unsuitable to be converted to a tanker...
That is indeed correct. Lord knows why he made such a self-destructive comment.... Was it just a ploy to keep the ageing 767 viable?
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Old 18th Aug 2015, 19:52
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tdracer,
Thanks for that info. Interesting, the last tanker / receiver full scale ground testing trial I saw was just with F34.
By the way, is it TD1, TD2 or TD3?

OAP
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Old 19th Aug 2015, 01:17
  #328 (permalink)  
 
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Reportedly, Boeing has in fact found buyers for the 'terrible teens' - and several of the "pre-teens' have already been delivered (Boeing wrote off the first three 787s several years ago - they're being gifted to museums). They've been updating the early build 787s at the "Everett Modification Center" or EMD. EMD is the same building where they are doing the KC-46 conversions (it's towards the south end of Paine Field, basically the opposite end as the main Boeing Everett). The early focus was on the slightly later production 787s as they needed less work and could be processed more quickly, then working 'backwards' towards the earlier aircraft that need more work.

Beagle, I've also 'heard' that the 787 is enough of a point design that it wouldn't make a good freighter either - I'm guessing that the main deck floor isn't strong enough and would require a major redesign (and unlike aluminum it's not a matter of simply increasing the gauge), but that's just an educated guess.

Onceapilot, I don't understand the question
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Old 19th Aug 2015, 13:05
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A video of an umbrella opening. please do not be offended.

Originally Posted by tdracer View Post


Scuttlebutt is that Boeing is going after the vendor that supplied the "mislabeled" stuff with a vengeance






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Old 19th Aug 2015, 13:31
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Beagle, I've also 'heard' that the 787 is enough of a point design that it wouldn't make a good freighter either - I'm guessing that the main deck floor isn't strong enough and would require a major redesign (and unlike aluminum it's not a matter of simply increasing the gauge), but that's just an educated guess.
The same thing was said about the 777 back in the day. It was supposedly too highly optimized for the passenger mission that neither a freighter nor a tanker mod would be cost effective. But that was overcome and there are now well over a hundred 777 freighters in service. I'd guess that 787 will eventually follow a similar path. As for the floor beams, it would seem that adding a few layers of carbon composite would be equivalent to upping the gauge of an aluminum floor beam. But perhaps more significantly, the 787 uses different kind of seat tracks than past aircraft. Maybe that will become a driver for a freighter version.
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Old 19th Aug 2015, 22:22
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777F has aluminium floor beams. The reason 777 pax to freighter conversion has not happened yet is because the floor beams would have to be replaced. Has been proposed but don't think started yet
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Old 20th Aug 2015, 18:53
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Freighter conversions are (generally) not driven by the engineering of the conversion. 90% or more of the engineering has been accomplished for a passenger to freighter conversion. The main driver historically has been the residual value of the donor passenger aircraft. Historically, residual value drops sufficiently after 20 years to make passenger to freighter conversions cost effective. But used 777s are holding their value longer than usual, so there aren't enough used 777s available to make a conversion program cost effective.

As for replacing the floor beams, that's relatively straight forward. All the floor boards would need to be removed anyway and once they're out, access to the floor beams is not that difficult. Much more difficult, complex, and invasive is adding an upper deck freighter door.
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Old 20th Aug 2015, 19:41
  #333 (permalink)  
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KenV wrote:
Much more difficult, complex, and invasive is adding an upper deck freighter door.
Well, Elbeflugzeugwerke managed to find a cost-effective way of converting the A300/A310 to include a freight door.... Customers came in droves.

Is it just a Boeing issue that makes such a conversion for the 777 difficult?
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Old 20th Aug 2015, 21:21
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Well, Elbeflugzeugwerke managed to find a cost-effective way of converting the A300/A310 to include a freight door.... Customers came in droves.
Is it just a Boeing issue that makes such a conversion for the 777 difficult?
Ummmm, no. Indeed, there is no "issue" at all. (You really seem to have a hard on for Boeing.) As already mentioned, there are well over a hundred 777 Freighters flying around. The engineering is done. As is the certification. The only reason I mentioned the door at all was in answer to someone suggesting that modding the floor beams was a problem for 777. It is not. That's pretty easy. Adding the door is much harder, but Boeing has done that countless times on several different aircraft types both large and small and has already done so on the 777.

As I already said, what's missing is availability of donor 777 passenger aircraft to convert into freighters. Without passenger aircraft to convert, there can be no conversion program. The problem is that it's really hard to find anyone willing to get rid of their used 777s. And if customers "came in droves" to convert A300/A310, it was because there were "droves" of used A300/A310 passenger aircraft that the airlines were getting rid of even though there was still lots of life left in them. That just is not happening with the 777. Yet. This may be due to there not being any real replacement for 777s. We'll have to wait and see if that starts happening when enough A350s and 787-10s enter airline fleets.
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Old 20th Aug 2015, 22:03
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Oh my, KenV , my query re. Boeing was intended to establish whether there is some constructional quirk which renders freighter conversion more difficult than it is for other manufacturers' aircraft...

Perhaps one reason customers preferred the A300/310 conversion out of choice, rather than the 767, was because the A300/310 has a wider fuselage cross-section (it's the same as the A330), providing greater cargo flexibility.
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Old 21st Aug 2015, 01:44
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The 787 main deck floor is an integral part of the fuselage barrel - it's not all bolted together like it is on aluminum aircraft. So strengthening the floor for cargo is non-trivial. A production freighter would require a complete redesign of the fuselage barrel (and likely new tooling), while retrofit would be a nightmare.


As for 767 freighters, Boeing has build over 100 new production 767-300F, with firm orders for over 80 more. As to why you don't see more 767 freighter conversions, perhaps it's because 767s are sufficiently valuable as passenger aircraft that they don't get parked until there is little life left in the airframe (there are a lot of 767 passenger aircraft with over 100,000 hours that are still in service).
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Old 21st Aug 2015, 08:06
  #337 (permalink)  
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tdracer, Back in 2005, senior Boeing executives stated that '...the 787 is designed so close to the edge for efficiency that it could not be modified as a tanker'.

Modifying that fuselage to include a boom and probably some additional fuel tanks would, as you indicate, require a lot of redesign. Whether the highly flexible wing structure would cope with the plumbing and hardpoint requirements for wing AAR pods is another unknown.

But never say never....
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Old 21st Aug 2015, 12:51
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Oh my, KenV , my query re. Boeing was intended to establish whether there is some constructional quirk which renders freighter conversion more difficult than it is for other manufacturers' aircraft...
As I already "established", Boeing has made freighter versions of essentially every jet airliner they've built, from the 707 to the 777. The only exception (so far) is the 787 but that's a brand new airplane and a freighter version usually comes decades after the passenger version. There are no "constructional quirks". Indeed there are at least TWO non Boeing companies offering 767 freighter conversions and one offering a 767 tanker conversion. So no, there are no construction "quirks".

Once again, the biggest driver of freighter CONVERSION demand is the availability of donor passenger aircraft with hours left on the clock. If the airlines continue to fly their old passenger jets rather than sell them, there are no passenger jets to convert. So far that's the case with both the 767 and the 777. There are precious few 767s and 777s with hours left on them that the airlines sell off. Although lately, some airlines are converting their passenger 767s to freighters rather than selling them off. It's a simple way for them to break into the freight hauling market.

The A330 is no different. The first A330 freighter conversion is scheduled to deliver in 2016, that's 24 years after the A330's first flight in 1992. 777's first flight was in 1994. Maybe we'll see the first 777 conversion 24 years after first flight, which would put that first conversion in 2018. But again, that depends on the availability of cheap used 777s. And that depends on the willingness of airlines to sell off their passenger 777s at cheap prices. So far, the 777 is holding its residual value very well so that may take quite a bit longer. The operative word there is "may". Once enough A350s and 787-10s enter service, the value of old 777s may decline. We'll have to wait and see.

As for the 767 supposedly being too narrow to make a good (or flexible) freighter, you may want to ask why FedEX and many other dedicated cargo carriers have bought literally hundreds of them. And these are pricey brand new freighters and not some el cheapo conversion. The A330-200F has the same cross section as the A300/310. So far less than 50 have been sold. So if sales numbers are the criterion (which I doubt), then one would need to conclude that the 767's narrower fuselage is an advantage rather than a detriment to being an efficient freighter.

Last edited by KenV; 21st Aug 2015 at 15:25.
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Old 21st Aug 2015, 12:57
  #339 (permalink)  
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Well, KenV, whichever airliner ultimately proves best for conversion to trash-hauling, it'll undoubtedly be safer than the woeful MD-11F....
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Old 21st Aug 2015, 13:24
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The 787 main deck floor is an integral part of the fuselage barrel - it's not all bolted together like it is on aluminum aircraft. So strengthening the floor for cargo is non-trivial. A production freighter would require a complete redesign of the fuselage barrel (and likely new tooling), while retrofit would be a nightmare.
The 787's floor is not integral to the fuselage barrel. See link below.

Boeing Images - Search Result

The fuselage barrel sections are indeed baked as in integral unit, but those sections do not include the floor beams or even the floor beam attach fittings. Indeed, not even the frames (ribs) are integral to the barrel sections, only the skins and longerons (excuse me, my Douglas is showing. Boeing calls them stringers) are integral. The frames are bolted on later (as opposed to riveted for aluminum airplanes) and then the floor structure is bolted to the frames. ZA005, the only 787 flight test aircraft that has been refurbished and delivered was refurbed here in San Antonio. We did a LOT of work on the main deck floor beams, floor boards, and seat tracks. And yes, those floor boards and floor beams all come out and can be replaced.

Personally, I doubt that an airliner will ever have an integral floor. Why? Heavy maintenance and mod. Heavy maintenance and mod is what we specialize in here in San Antonia and doing that on an airplane with an integral floor would be a nightmare. There's a LOT of stuff that runs under the floors that would be really hard to gain access to if the floor was integral to the fuselage. Especially over the wing where there is no lower lobe.

I think the bigger issue will be adding a freighter door. That 787 fuselage barrel is glued together and baked in an autoclave. You can (relatively) easily add doublers and other parts to beef up an aluminum structure to compensate for a big hole cut in the side. I have no idea if that is possible for a plastic fuselage. At least today. If history holds, Boeing and Airbus will have about 20 years to figure out how to do that.
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