bikerthai From United States of America, joined Apr 2010, 1598 posts, RR: 4 Reply 5, posted (8 months 2 weeks 9 hours ago) and read 5995 times:
Quoting Spacepope (Reply 2): Did it actually lose the boom or the hose? They say both in the article, however on the EADS boom, the parts are separate.
I know we engineers are not English majors, but a careful reading of the article states:
"A boom is a rigid hose that extends from the undercarriage of the plane . . ."
which is "literary" correct . . .
"rigid hose" sounds better than a "pipe".
Spacepope From Vatican City, joined Dec 1999, 2739 posts, RR: 1 Reply 6, posted (8 months 2 weeks 8 hours ago) and read 5932 times:
Quoting bikerthai (Reply 5): "A boom is a rigid hose that extends from the undercarriage of the plane . . ."
Kind of a strange thing to hang off the landing gear, however I'm just a paleontologist, what do I know! So it was indeed the whole dangly off the back of the aircraft part that came loose.
If there only was a word for a rigid hose. Something like pipe. Quick, to the Pulitzermobile!
kanban From United States of America, joined Jan 2008, 2468 posts, RR: 21 Reply 7, posted (8 months 2 weeks 8 hours ago) and read 5911 times:
A rigid hose also implies a flaccid state.... Don't think we want to go there
It's odd that there is no back up retention device that would prevent this.. like the chains used as back up on trailers.. although landing the tanker with an 18 ft pipe dangling beneath it's belly might be impossible
what is also curious is can this happen during refueling taking out the receiver a/c.?
mffoda From United States of America, joined Apr 2010, 908 posts, RR: 0 Reply 8, posted (8 months 2 weeks 8 hours ago) and read 5886 times:
Form the article:
"A boom is a rigid hose that extends from the undercarriage of the plane to feed a second aircraft with extra fuel so it can continue flights without landing. Designed and built by Airbus, the boom measures 11.6 meters (38 feet) when retracted and 18 meters when fully extended."
The last sentence clearly refers to the boom and not a Probe-and-drogue system.
kanban From United States of America, joined Jan 2008, 2468 posts, RR: 21 Reply 10, posted (8 months 2 weeks 6 hours ago) and read 5789 times:
Quoting bikerthai (Reply 9): You don't want the chains. It would be like having an oversize nun-chuck whipping around near your stabilizer.
recognize that if fully detached it's a problem, but at some point of extension, and before reaching the drop point, there should be a stop.. even if it has an override allowing the operator to jettison the unit like a lizard dropping it's tail.. by the way are they designating this series of the planes "Lizards"?
Dynamics is not my forte. But once things start to go, I don' t think there's much you can do except to let it go gracefully. Otherwise, any additional weight for a "back-up" device would be better spent beefing the boom up.
The picture is just not consistent with the rest of the article, where they describe the piece that was dropped as being a boom, and they point out in the text that they understand the difference between a boom and a drogue/hose setup.
The picture is just not consistent with the rest of the article, where they describe the piece that was dropped as being a boom, and they point out in the text that they understand the difference between a boom and a drogue/hose setup.
That article in AW tells the story of the photo...
"Four tankers have been delivered to Australia as well as a single aircraft to the U.K., which uses a centerline retractable hose system instead of a boom. A single Saudi Arabia tanker has been completed but has not yet entered operations."
from above: "as well as a single aircraft to the U.K., which uses a centerline retractable hose system instead of a boom.'
KC135TopBoom From United States of America, joined Jan 2005, 11711 posts, RR: 52 Reply 15, posted (8 months 1 week 6 days 10 hours ago) and read 5290 times:
Quoting bikerthai (Reply 9): Must have been some file photos of a different airplane . . . you know how that is . . .
No, not a different airplane, that is still an A-330MRTT. But it is a different version. The picture is of the RAF Voyager KC3 version which does not have a boom (neither does the Voyager KC2 version). The picture is of an airplane that has not been delivered to the RAF yet. IIRC, the RAF currently has one Voyager KC2 in flight testing. The difference between the KC2 and KC3 versions is the KC3 has the centerline hose drum-reel system in addition to the WARPs. The KC2 version only has the WARPs.
neutronstar73 From United States of America, joined Mar 2011, 215 posts, RR: 0 Reply 16, posted (8 months 1 week 6 days 8 hours ago) and read 5234 times:
How many times does this have to happen for EADS? Don't they know how to put a tanker together or what?
First they had a boom fall off during testing. Then the embarrassing issue that the UK tankers couldn't refuel Tornado aircraft. Now they have a second boom fall away.
Maybe they should do a bit more design work or just farm out the boom work to Boeing.
mffoda From United States of America, joined Apr 2010, 908 posts, RR: 0 Reply 17, posted (8 months 1 week 6 days 1 hour ago) and read 5045 times:
I've been considering this response to this thread for a couple of days now. While not wanting to initiate a flame fest, it reminds me of the heated discussions regarding the USAF tanker competition. Particularly about the program risks for either contender.
In light of these recent developments regarding the two recent boom losses by the A-330MRTT, one has to wonder about the experience level of the two competitors to support this niche capability? Boeing 60+ years of continuous production/support with refueling booms. And Airbus with very little, primarily probe and drogue experience.
All other considerations aside, It would seem that this capability is of primary concern to the USAF, who are so much more reliant on the boom then most of our allies are. I'm not sure how long this boom issue will continue until a fix is found (as this does not seem to be a software fix as originally thought from the first incident), but this would certainly result in program delays and cost increases (Risk) yes?
kanban From United States of America, joined Jan 2008, 2468 posts, RR: 21 Reply 18, posted (8 months 1 week 5 days 9 hours ago) and read 4887 times:
TopBoom, what are the mechanics of boom tube extension and retraction, and how would a boom tube detach itself or extend itself clear out of the boom? (feel free to correct my terminology)
KC135TopBoom From United States of America, joined Jan 2005, 11711 posts, RR: 52 Reply 19, posted (8 months 1 week 5 days 6 hours ago) and read 4824 times:
Assuming the EADS Boom is of similar construction to the Boeing Gen III/IV/V/VI Booms, and attached in a similar manner, this could be a failure of the trunion where the Boom actually attaches to the tanker. The trunion has mechanical limits, as any piece of machinery does. Remember the Boom is a seperate piece of equipment from the tanker itself. On the Boeing Gen III Boom (KC-135) which I am most familure with, the extension/retraction mechinism is a chain and sprocket arrangement, driven by a hydraulicly powered motor. There are two mechanical stops, at full extension and full retraction. The ruddervators are hydraulic powered flight control surfaces, controlled by valves connected to the ruddervator stick, which is similar to the stick in a fighter aircraft. The extension/retraction is a seperate lever on the instrument panel. The KC-10 uses joysticks on the armrests for these functions, and my guess is this is what is in the A-330MRTT.
Not knowing what parts failed and what parts remained attached to the tanker, I can only guess what the failure might be.
1.) An unknown hydraulic or electrical surge that cause the ruddervators to become uncontrolable, thus exceeding the trunion limits and the entire boom breaking off.
2.) A failure of the extension mechenism, overruning the mechanical stop and shooting the fuel tube out of the Boom.
legs From Australia, joined Jun 2006, 207 posts, RR: 0 Reply 21, posted (8 months 1 week 5 days 2 hours ago) and read 4699 times:
Forgive what might be a slightly silly question at this point, but did Airbus/EADS develop the boom system themselves, or did they contract the boom design out to a third party?
KC135TopBoom From United States of America, joined Jan 2005, 11711 posts, RR: 52 Reply 22, posted (8 months 1 week 5 days ago) and read 4648 times:
Quoting legs (Reply 21): Forgive what might be a slightly silly question at this point, but did Airbus/EADS develop the boom system themselves, or did they contract the boom design out to a third party?
They developed their own Boom after looking at the French C-135FRs.
KC135TopBoom From United States of America, joined Jan 2005, 11711 posts, RR: 52 Reply 24, posted (8 months 1 week 2 days 10 hours ago) and read 4198 times:
Has anyone got more information on this incident? Do we know what parts of the Boom fell of, or was it the entire Boom? Do we have any pictures of the tanker, after it landed, or the Boom laying on the ground in Spain? I would think the tanker received at least some damage to its hydraulic and electrical systems.
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