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UK military spending review   General Military Discussion

Started 13/3/21 by autogun; 12733 views.
schnuersi

From: schnuersi

8-Jun

DavidPawley said:

And welds that have gaps in them.

Seriously? How did they manage to do that? This is such a basic thing if this isn't done right it can be safely assumed nothing is.

RovingPedant

From: RovingPedant

8-Jun

schnuersi said...

Seriously? How did they manage to do that? This is such a basic thing if this isn't done right it can be safely assumed nothing is.

It's entirely possible that someone isn't aware of stitch welding. I seem to recall mention that the spacing in some of the stitch welded parts were irregular, but that's kind of a different thing.

schnuersi

From: schnuersi

8-Jun

RovingPedant said:

It's entirely possible that someone isn't aware of stitch welding.

This is possible but unlikely.
Usually allmost all parts of an AFV are seam wealded. Only this way it will be gas and water tight. Also the load and potential stress on most parts require it.

RovingPedant

From: RovingPedant

8-Jun

schnuersi said...

This is possible but unlikely.
Usually allmost all parts of an AFV are seam wealded. Only this way it will be gas and water tight. Also the load and potential stress on most parts require it.

Any joints that have a sealing or ballistic function yes. Seam welded and on both sides. 

Internal or external stiffening ribs or welds which do not have sealing or ballistic functions are often stitched to reduce the heat and residual stress put into the structure.

DavidPawley

From: DavidPawley

8-Jun

No, it was just shitty workmanship and no QA, not stitch welding.

The hulls were not within spec and that's why they weren't accepted.

Running gear couldn't be installed because hull out of true is one complaint I recall.

DavidPawley

From: DavidPawley

8-Jun

schnuersi said:

if this isn't done right it can be safely assumed nothing is.

Correct.

graylion

From: graylion

9-Jun

DavidPawley said:

No, it was just shitty workmanship and no QA, not stitch welding. The hulls were not within spec and that's why they weren't accepted. Running gear couldn't be installed because hull out of true is one complaint I recall.

where were they built?

DavidPawley

From: DavidPawley

9-Jun

Spain. Shipped to UK to be mated to other components.

RovingPedant

From: RovingPedant

10-Jun

The hulls are built in Spain and the assembly is in the UK (Wales to be specific) but I don't know exactly where the split is. I suspect that running gear and power train is fitted in Spain before shipping ( it would be a pain to move around otherwise) while turrets and electronics are fitted in the UK. Consequently much of what is reported, if true, is an internal problem for GD, provided that they don't try to ship it to the MoD in that condition. That said one of the official reports noted that much of the noise and vibration generated by the platform originates with problems with the drivetrain and running gear*

I've seen complaints about engineering problems before and often they are either not true or an extrapolation from what is true based on a lack of engineering knowledge, so I prefer to wait for a bit more detail before flying off the handle. The QA problems with Ajax fabrication have ranged from welds being the wrong length (quite possible but not ideal if you're stitch welding) to the hull sides being different lengths (pretty difficult if they're being cut on anything like modern machinery) to welded bosses being true to each other but variable to other features (very common on previous generation AFVs - you'd like to think we've tightened up general tolerances a bit) but people like to take that kind of information and create an impression of tacked together wriggly tin  with chewing gum stopping the more egregious leaks long enough to get it out of the factory.  I don't think Ajax is perfect but it strikes me that it's something that can be fixed.

*It must be borne in mind that noise and vibration on all tracked vehicles mostly originates with the drivetrain and running gear, even when it's working perfectly - it's fundamentally an awful lot of metal being thrown around at high speeds and lots of metal-to-metal impacts.

schnuersi

From: schnuersi

11-Jun

Such problems really are not uncommon.
As soon as multiple companies are involved things get messy quickly. If its multiple companies from multiple countries it gets worse and if its multiple companies from multiole countries from multiple cooperations its an invitation to disaster.

Several of the current multi national projects suffer from this. Even the ones concidered successfull.
I for example know that the final assembly of the Boxer is a nightmare because this is where the parts produced all over Europe come together. Especially the mission module and the hull. The latters often don't fit. Some workers told me they usually don't fit. The tollerances are defined and given as per international norm but there are local interpretations and preferences. This is enough to cause quite a lot of trouble.

RovingPedant said:

That said one of the official reports noted that much of the noise and vibration generated by the platform originates with problems with the drivetrain and running gear*

That really is rather problematic. Vibration problems usually are because of the interaction of several parts. There often is no single source or cause. This can be very tough to pinpoint and fix. It seems strange though that Ajax has such troubles since its based of an exsiting and mature vehicle. This hints at either poor integration of systems and modifications or changes to the basic layout without proper analysis and testing. If the latter is the case these proplems might not be fixable at all without a major rework.

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