WARNING To all Meteor owners.

Isn’t this just time expired magnesium – square grain structure causes a clean, rapid break from a micro crack. Owners of fancy race cars just replace it after a certain amount of cycles/hours. WW2 aircraft never lasted long enough for it to be an original issue in the 40’s. It is today, if the WW2 component is nudging 75 years old, with a history of hard landings and then keen volunteers looping towing cable from leg to tractor.

Folks want to replace original mag castings with aluminium these days, but it is probably the mag casting acting as a sacrificial anode that preserved the larger aluminium structure over the decades. I can understand if a mag casting is deeply buried within a structure, but if it bolts on, it can be replaced after a certain number of hours, if you invest in the casting pattern. If the aluminium has higher mechanical strength than the magnesium it replaces, it might add a factor of safety, or it might change the way force is transmitted through a structure. The world divides into magnesiumphobes and magnesiumphiles.

You have to be German to know and love magnesium and bratwurst. An old goat of a thing like a Meteor would have DTD285 magnesium castings, basically prewar German Elektron, same as half the mass of the Luftwaffe.

What to do with the Museum static with low budget kept out in the weather? Maybe steel stands under the jacking points? The maggie is just slowly fizzing away…

The pin appears to be located inside an aluminium bronze (spec DTD197A in old money but now B23) bushing which is a shrink fit into the aluminium casting/forging, so the pin will rotate within the bush.

Lack of lubrication may well be some of the issue, as not only does it lubricate the joint it also keeps moisture at bay if done on a regular basis. There is a reason why a re-greasing of landing gear is called up after a pressure wash (if it is allowed at all, depends on operator and advice from gear manufacturer).

Also, steel pivot pin in Ali casting equals dissimilar thermal expansion rates (and if not lubricated dissimilar metal corrosion), so these things will crack.
How long before we see museum pieces with trestles permanently supporting them?

Being as they are displayed outdoors I wonder how often water ingress in the joint freezes over the years. Water expands when it freezes and can cause internal stress loading.

Reminds me of a few occurrences on F27 Dowty NLG where a similar thing happens on the wheel lever shock absorber mounting lugs, see here for a report on one such instance
http://rnsa.is/media/1433/2008-05-21_m07407_aig35_tf-syn_final_report.pdf

With the F27 there was a mandatory modification to carry out a heat treatment to the main aluminium parts that basically changed the specification from DTD5024 to DTD5104 due to instances of stress corrosion (and also extended the safe life of a number of compoents); although the gear subject in the report should’ve been modified by that time it maybe other landing gears produced in that era by Dowty are susceptible to stress corrosion.

As far as I’m aware the NLG on the F27 are still subject to regular NDT inspection on the shock absorber mounting lugs on the wheel lever amongst other parts.

Is it weldable? There is a cracking aircraft welder in Long Eaton

er….

Glad to hear no one got hurt, the problematic Valiant spec was DTD683 – is this of that composition or is it just plain magnesium?

We have moved it with no undue force around the taxiway to the museum it appears to be old the other side has failed on the fork due to I guess stress. It’s a clean failure with no marks or corrosion. The aircraft is fairly complete we now have a winch but need a pylon a rear seat stolen at North Weald I believe and a stick top. We need 2 catches for the centre fuel tank cover. I wondered why the bottom aerial at the back was filed off the tacan shark fin one. We would like to get 2 under wing tanks if possible.

‘224 – Poor old girl. She’s been out doors since the early 70’s!
Its a fact of life that old castings will eventially fail, due to corrosion, and being under constant strain. Notwithstanding that an airframe like this that has been moved around a lot in its life.

I used to help look after her at North Weald in the 80’s. One story that comes to mind were the events that took place on the night of the mid-October gales in 1987. ‘224 used to be kept on the Southern side of the airfield, and the night of the strong gales, she took a trip across the airfield, mainly backwards! The aircraft did not have any of the nose weights fitted due to the forward structure being mid-refurbishment, and the gales pushed the tail down and moved it right across to the western side of the airfield. It didn’t touch anything else fortunately, and somehow managed to stay on the perimiter track. Underneath the tail, there used to be a small triangular aerial fitted, that due to the tail scraping was pretty much worn away. Only the rubber skid prevented it from making more damage.

How complete is the airframe now?

[ATTACH=CONFIG]253577[/ATTACH]

Another place to look for cracks on Meteor U/D.

(Found during restoration of WS774)

Canberra nose leg and Shackleton tail leg are identical, thankfully, and it saved our bacon when we had a massive crack develop on WR963’s unit. The only differnces were the mudguards fitted on the Canberra, and the gear door actuator mechanism is slightly different on the Shackleton.

Aren’t the Mk.2 tail wheels related closely with Canberra nose legs?

John

I doubt anyone will go as far as x-ray or ultrasound; but a strip of paint and a visual check (and some dye penetrant if it looks suspiscious) is easily done. I know we’ll be looking at these areas on WS788 at Elvington tomorrow.

As has been said further up- its not just Meteors. Remember my fun with Shackleton tailwheel legs a few years ago?

Regards

Rich

I would expect NDT-ing for a static aircraft might be overkill (at least in a low-slung aircraft like the Meteor….an airplane that someone could conceivably be under might be another matter) and far too expensive for most owners.

For higher wing or large types, one day there might be restrictions for being under the thing.

It’s quite possible that the leg could have been cracked when the aircraft had been moved in the past. Most museum aircraft are moved by tractor with unskilled and untrained personnel, as well as on grass, which can induce severe transverse loading on undercarriages, so it’s quite possible the seeds were sown then for a future failure.

It’s been the case in the past that parts have failed long after the initial (rough handling) damage was done leading to failure and, in the case of flying aircraft, a serious incident or crash. Thank goodness there was no-one around when this leg broke.

Meteor legs are particularly beefy and were not prone to failure in service. However, they (or any other aircraft part) was not intended to sit outside unserviced for 40 years and still be expected to do the job for which they were intended – without maintenance. And there’s the rub; should we subject our static aircraft to regular and fairly intensive maintenance to ensure the structural integrity is maintained and discovered before, not after, an incident (which could be serious) has occurred.

Indeed, there may be a requirement by insurance companies that a (better) system of inspection is carried out by knowledgeable persons, though how a crack would be spotted in a mainleg is anyone’s guess. Perhaps there should be NDTing of critical parts?

I may be able to help with a replacement, Varsity.

Anon.

Watch out for Canberra ‘Epsteins’ then, they were/are known for cracking in storage! Although cracked ones could be flown with reduced g loads, but for how long I don’t know.

I was under the impression that quite a lot of the 50s and 60s era legs are pretty unstable due to their chemical composition which degrade over time leading to significant weakening. I believe Lightning legs are particularly likely to be prone to sudden failure. Think it came up in discussion I had with a museum recently that it was a flagged item on their conservation agenda.

FB

Is it weldable? There is a cracking aircraft welder in Long Eaton

I don’t want to disrespect your aircraft but the pin does look a bit corroded on the bottom in the picture. I suspect that this, or maybe frozen condensation on the unloaded side, has expanded causing a hairline crack. When the second crack appears causing total failure is then a matter of time.

Thanks Bruce.

John