The solution will be:
1) undo bolts
2) apply higher strength loctite
3) do up bolts
Bet that costs them a few million tho...
Paris because she knows how to tighten my nuts.
The famous V-22 Osprey tiltrotor, which flies like a plane but tilts its props upwards to land and take off like a helicopter, appears to have hit yet another technical snag. The V-22 with rotors tilting Hey, Joe - is it supposed to make that rattling noise? The troubled military combo-copter, which suffered through a …
I would have thought that for operations in theatre a quick fix/workaround involving lock-wire and/or locktite* (other brands of thread locking compound are available) would keep the Marines flying for now.
*unless it is a locktite issue. It doesn't work with heat as any fule no.
Paris, 'cos she's tightened a few nuts in her time...
... split pins through the nut and the bolt? Didn't this used to be fairly simple idiot proof technology that meant nuts were not overtightened and could not come loose. Easy to inspect and cheap to replace.
I would have used the boffin pic but this is not rocket science... merely aeronautical engineering.
Mines the one with the pliers and a bent screwdriver in the pocket.
As a member of the US Air Force for over 6 years and working on the EC-130H, findings like this are not completely uncommon with air frames. Even after 50 years of service, the C-130 has the occasional issue (I can recall this happening three times over my 6 years) that will ground the entire fleet for a day while instructions on how to fix the problem are disseminated. Most issues are "patched" via updated maintenance Technical Orders (TO's).
The spookiest thing to consider is that on a long enough time line all equipment will achieve catastrophic failure. Things will always break and sometimes 2 or 3 of the wrong things break at the same time and elevation becomes greater than altitude and your equipment will "give up the ghost".
What about the Osprey makes this more difficult to prevent than on any other helicoptor?
It's a side effect of vibration, and machines have been using a wide range of solutions for a long time. Drilling a hole through a nut and bolt, and threading wire through, went out of favout before WW2. Aviation mechanics have been checking critical parts since before the RAF was formed.
No wonder there were questions about the maintenance standards.
"This thing has been a death trap since inception but the enemy loves them, loud, slow moving targets that if not shot by a blind man with an Ak-47, it will likely fall out of the sky on its own!" Which is very similar to the twaddle certain armchair generals and self-proclaimed experts said about the early helicopters, right up to the Vietnam War when the Huey finally silenced the anti-helo brigade. Even Lewis's much-loved Chinooks had their fair share of teething troubles and maintenance issues, and the Chinook didn't break new ground technically in the same way the Osprey has.
In normal flight mode the Osprey has the advantage of a conventional transport plane - higher speed and better range than a conventional helo - and can land vertically like a helo. Yes, the price is eye-watering, and the budget has gone very high, but even today's Osprey offers the US forces a rapid vertical insertion and extraction platform no other country can match. Personally, I'd rather the RAF bought them than Lewis's Chinooks.
Anonymous Coward is trying to be clever by asking CC "So how many have been lost in Iraq to enemy action so far?" Nice try.
... the fact that our AC is no doubt aware of is that the Osprey are being deployed to Iraq in a largely photo opp / PR effort with extraordinary precautions used to keep them out of harms way.
Osprey will be successful in Iraq because the program depends on it, not because they will be in any way tested in a realistic combat environment.
drilled nuts and lockwire out of favour since WWII??
Not on a lot of aircraft I fly.
Simple, light, cheap, effective and easy to check in preflight.
Also much easier to deal with when the bolts need to come out than locktite.
Lockwire dates back decades, but so do many effective safety methods.
Bring on the Simplex pusher contra-rotating chopper anyway.
Also simpler mechanically, same speed, same landing as V22.
If any of you lot are into racing any thing remotely considered mechanical or powered by an infernal combustion engine you will know that lock wire is a must no lock wire no race also if it is heat and fuel that is degrading whatever is being used then they should try Hylomar© or Golden Hermitite© both are nonsetting thread compounds if they don't already that is.
RE: V-22 in Iraq
"....the fact that our AC is no doubt aware of is that the Osprey are being deployed to Iraq in a largely photo opp / PR effort with extraordinary precautions used to keep them out of harms way...." Hmmmm, not what I heard. I don't know any Osprey pilots myself, but I've been told the Osprey's speed makes it prefered for overflying areas with expected heavy groundfire. The one downside of the V-22 in such ops has been the lack of a forward-firing gun to lay better suppressive fire, but I hear an under-nose turret may soon sort that.
RE: What If
"... they'd taken all the money spent on V-22 Osprey development, testing and production and just bought more Chinooks instead? Actually, a lot, lot, lot more Chinooks." The basic Chinook design is fifty years old. It wasn't exactly cheap itself to develop, and to produce a version that offers the same performance as the V-22 would require a massive investment and a lot of new tech. Whilst relatively reliable, it is still slow and short on range compared to the Osprey.
My hope is the USMC will stick with it long enough to get it sorted and the unit price down, then Westland can cut a deal to make some here in the UK for the RAF. ;)
I heard this from a locktite salesman so take it with as much salt as you like...
Apparently there was a mod for the Mirage fighters that required taking the wing apart at a considerable cost, just to apply a drop of locktite to a nut on the end of a hydraulic actuator piston rod. The cost of the dismantling did not appeal to the Aussie air force, so after a bit of thought they came up with a way of reaching in through an available opening with a long paintbrush. The problem is of course that locktite has wonderful wicking properties, which are good for making sure it finds its way into the threads, but not so good when it finds its way along the actuator arm. Of course the paintbrush approach did not lend itself to fine control of the quantity applied. Supposedly the pilot found out about this when one of the elevons did not work after take off. The locktite had wicked through the nut and the assembly on the end of the rod, along the rod, and into the hydraulic seal on the cylinder, locking the whole thing solid. The way the story was told to me, he did get the thing down again in one piece.
I do have my doubts about this story....surely a competent pilot would check the freedom of movement of the controls after the airframe has been worked on? On the other hand, it was the Aussies. I can believe it wicking into place where it is not wanted. I had some leak onto a selection of tools on the bench once, it glued them together quite well even exposed to the open air.
In the old days we had castellated nuts with a split pin. Simple, reusable, utterly bloody idiot proof (it's very easy to tell from visual inspection if someone's reused a split pin - and such is rarely a problem anyway) and never come undone unless deliberately removed.
Now we have nyloc nuts. More complicated, must be replaced rather than reused, impossible to tell without dissassembly if a new one's been used or not and have a nasty habit of loosening themselves. But quicker to assemble and thus preferred by manufacturers.
We have now developed thread-locking compounds to disguise the shortcomings of self-locking nuts....
Isn't progress wonderful?
F117 reported to have taken off missing with 7 bolts missing. Specifically 7 (of the 8) holding the wing on.
Amazingly it still took off.
*Read in an article on the strength of composite strucutures and peoples perception of them as failure prone. Not really surprising if that is the usal standard of maintenance.
Incidently some years back NASA was listed as America's biggest user of Lockwire & split pins as it seems to have been phased out everywhere else.
You'd expect this to be on the list of "Stuff we should check in design" but I guess not.
golden hermitite and (blue) hylomar are gasket compounds, not adhesives!
loctite 648 is a high strength, high temperature adhesive, failing that, uhu "endfest 300" epoxy will withstand 150c+..
however, using those make dissassembly very difficult.
a far better solution would be a castle nut and lock/split pin.
Yes they do give lots of warning IF you look at them often enough,but I have seen several lorries with only one on any of the wheels and lots of split ones at the side of the road also great at a few hundred RPM but the prop on this beast probibly goes a bit faster than that.
@ William Henderson I know that.
Biting the hand that feeds IT © 1998–2022