Recliner <recliner.usenet@gmail.com> wrote:
> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com> wrote:
>
>> <MrSpud_pw@245n.co.uk> wrote:
>>> On Sat, 17 Jul 2021 15:49:32 -0000 (UTC)
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> <MrSpud_e2v98p@w3w6mngetumx5n9ivmowik.gov> wrote:
>>>>> On Sat, 17 Jul 2021 15:20:20 -0000 (UTC)
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> Talking about high costs, the latest MR (arrived today) reports that
>>>>>> several vehicles may have to be replaced from 800026 and 802005, as such
>>>>>> large body sections were cut away for analysis that it won't be viable to
>>>>>> weld in new sections. It's unclear how many will need to be replaced.
>>>>>>
>>>>>> It's now thought that all the 800, 801 and 802 sets in service (182 sets
>>>>>> with four operators) will eventually develop the cracks, so Hitachi is to
>>>>>> set up repair bases at Eastleigh and Newton Aycliffe. The 5-car 800s will
>>>>>> be first in line for the repairs, as they're the worst affected.
>>>>>
>>>>> Sounds like the 8xx series is slowly changing from the best of railway tech
>>>>> into an absolute turkey. Its a shame, but I find it hard to believe an
>>>>> experienced railway builder like Hitachi couldn't forsee this problem. Its
>>>>> hardly some high tech never-done-before engineering.
>>>>
>>>> The problems seem to be because the DfT demanded the unusually long, thin
>>>> 26m body. UK loading gauge (effectively, narrow gauge) bodies aren't
>>>> usually more than 23m long. That seems to have led to extra stresses around
>>>> the bogie bolsters. It's not clear if the latest cracks, in the coupler
>>>> plates, are also a consequence of the longer overhang, and consequently
>>>> greater movement at the couplers due to the over-long bodies.
>>>
>>> Sure, but all this can be and should have been modelled and frankly its basic
>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>> that neither the engineers or the modelling computers forsee this.
>>>
>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>> it charges so much for them that it's probably still in the bkack.
>>>
>>> More than likely.
>>>
>>>
>>
>> You have a touching faith in modelling……..
>
> Neil does have a very good point that an experienced train builder like
> Hitachi really should be able to design/test new
> trains that don't quickly develop expensive cracks in multiple places.
> There are suggestions that they chose the wrong
> alloy for one component, failed to heat treat it properly after the
> welding, and obviously messed up the finite element
> modelling. Those look like novice mistakes (I was performing stress creep
> cycle analysis using finite element models
> almost 50 years ago, and thought things had moved on a bit since then).
>
> It's not as if it's a revolutionary new design: the A train family has
> been in service for decades, and in service in
> the UK for over a decade. Yes, there are some new elements in the IETs,
> but surely Hitachi knows the design well enough
> by now to be able to evolve it without these embarrassing problems.
>

Perhaps over confidence. Having designed similar but shorter carriages they
may not have considered that the longer vehicles might have had a strongly
non linear effect in some forces in critical areas. Modelling is only as
good as the quality of your model and the quality of the inputs you give
it. Japan also prides itself in the speed from start to delivery. That, of
necessity, will reduce testing, where in this case the faults only become
apparent after a certain time. In effect they’ve missed out the beginning
of the bath tub curve.

Tweed wrote:

> Modelling is only as
>good as the quality of your model and the quality of the inputs you give
>it.

Quite! I recall a colleague passing data from a train
performance program to a sub-contractor whilst preparing for a
quotation. After a few iterations of different input conditions,
it was noticed that the program output didn't seem to be affected
by significant changes.

Back to the drawing board. :-(

Chris
--
Chris J Dixon Nottingham UK
chris@cdixon.me.uk @ChrisJDixon1

Plant amazing Acers.

On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
Tweed <usenet.tweed@gmail.com> wrote:
><MrSpud_pw@245n.co.uk> wrote:
>> Sure, but all this can be and should have been modelled and frankly its
>basic
>> engineering. It doesn't say a lot about Hitachis railway engineering division
>
>> that neither the engineers or the modelling computers forsee this.
>>
>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>> it charges so much for them that it's probably still in the bkack.
>>
>> More than likely.
>>
>>
>
>You have a touching faith in modelling……..

If you ever fly in an airliner you'd better had too. Or did you think they're
still designed on boards by men with rulers and set squares?

On Sun, 18 Jul 2021 13:49:30 -0000 (UTC)
Tweed <usenet.tweed@gmail.com> wrote:
>Recliner <recliner.usenet@gmail.com> wrote:
>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
>> Neil does have a very good point that an experienced train builder like
>> Hitachi really should be able to design/test new
>> trains that don't quickly develop expensive cracks in multiple places.
>> There are suggestions that they chose the wrong
>> alloy for one component, failed to heat treat it properly after the
>> welding, and obviously messed up the finite element
>> modelling. Those look like novice mistakes (I was performing stress creep
>> cycle analysis using finite element models
>> almost 50 years ago, and thought things had moved on a bit since then).
>>
>> It's not as if it's a revolutionary new design: the A train family has
>> been in service for decades, and in service in
>> the UK for over a decade. Yes, there are some new elements in the IETs,
>> but surely Hitachi knows the design well enough
>> by now to be able to evolve it without these embarrassing problems.
>>
>
>Perhaps over confidence. Having designed similar but shorter carriages they
>may not have considered that the longer vehicles might have had a strongly
>non linear effect in some forces in critical areas. Modelling is only as

So you're saying their models and engineers didn't take into account the
effect of greater leverage forces? If they ignored something that fundamental
what more complex factors did they skim over too?

<MrSpud_17VwhRsCh@59j51jh.tv> wrote:
> On Sun, 18 Jul 2021 13:49:30 -0000 (UTC)
> Tweed <usenet.tweed@gmail.com> wrote:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
>>> Neil does have a very good point that an experienced train builder like
>>> Hitachi really should be able to design/test new
>>> trains that don't quickly develop expensive cracks in multiple places.
>>> There are suggestions that they chose the wrong
>>> alloy for one component, failed to heat treat it properly after the
>>> welding, and obviously messed up the finite element
>>> modelling. Those look like novice mistakes (I was performing stress creep
>>> cycle analysis using finite element models
>>> almost 50 years ago, and thought things had moved on a bit since then).
>>>
>>> It's not as if it's a revolutionary new design: the A train family has
>>> been in service for decades, and in service in
>>> the UK for over a decade. Yes, there are some new elements in the IETs,
>>> but surely Hitachi knows the design well enough
>>> by now to be able to evolve it without these embarrassing problems.
>>>
>>
>> Perhaps over confidence. Having designed similar but shorter carriages they
>> may not have considered that the longer vehicles might have had a strongly
>> non linear effect in some forces in critical areas. Modelling is only as
>
> So you're saying their models and engineers didn't take into account the
> effect of greater leverage forces? If they ignored something that fundamental
> what more complex factors did they skim over too?

That’s entirely possible. If there’s an effect they didn’t anticipate
either their model may not have covered it or they may not have
investigated the conditions that cause it.

Sam

--
The entity formerly known as Sam.Wilson@ed.ac.uk
Spit the dummy to reply

On Mon, 19 Jul 2021 10:35:31 -0000 (UTC), Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:

><MrSpud_17VwhRsCh@59j51jh.tv> wrote:
>> On Sun, 18 Jul 2021 13:49:30 -0000 (UTC)
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
>>>> Neil does have a very good point that an experienced train builder like
>>>> Hitachi really should be able to design/test new
>>>> trains that don't quickly develop expensive cracks in multiple places.
>>>> There are suggestions that they chose the wrong
>>>> alloy for one component, failed to heat treat it properly after the
>>>> welding, and obviously messed up the finite element
>>>> modelling. Those look like novice mistakes (I was performing stress creep
>>>> cycle analysis using finite element models
>>>> almost 50 years ago, and thought things had moved on a bit since then).
>>>>
>>>> It's not as if it's a revolutionary new design: the A train family has
>>>> been in service for decades, and in service in
>>>> the UK for over a decade. Yes, there are some new elements in the IETs,
>>>> but surely Hitachi knows the design well enough
>>>> by now to be able to evolve it without these embarrassing problems.
>>>>
>>>
>>> Perhaps over confidence. Having designed similar but shorter carriages they
>>> may not have considered that the longer vehicles might have had a strongly
>>> non linear effect in some forces in critical areas. Modelling is only as
>>
>> So you're saying their models and engineers didn't take into account the
>> effect of greater leverage forces? If they ignored something that fundamental
>> what more complex factors did they skim over too?
>
>That’s entirely possible. If there’s an effect they didn’t anticipate
>either their model may not have covered it or they may not have
>investigated the conditions that cause it.

There were two main differences with the IETs, compared to previous A Trains, and it could be that Hitachi didn't
properly model the combination of the two:

- Much longer carriages (the class 395 cars are 20m long, while class 800 cars are 26m long)

- Heavy diesel gen-sets and fuel tanks mounted under the motored cars, which needed higher floors as a result.

Most A Trains are Cape gauge commuter or regional trains, with maximum speeds of about 120-160 km/h, so the class 800
power cars are much longer, much heavier, and run at much higher speeds than most A Trains (apart from the shorter,
lighter class 395s).

Recliner <recliner.usenet@gmail.com> wrote:
> On Mon, 19 Jul 2021 10:35:31 -0000 (UTC), Sam Wilson
> <ukr@dummy.wislons.fastmail.co.uk> wrote:
>
>> <MrSpud_17VwhRsCh@59j51jh.tv> wrote:
>>> On Sun, 18 Jul 2021 13:49:30 -0000 (UTC)
>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
>>>>> Neil does have a very good point that an experienced train builder like
>>>>> Hitachi really should be able to design/test new
>>>>> trains that don't quickly develop expensive cracks in multiple places.
>>>>> There are suggestions that they chose the wrong
>>>>> alloy for one component, failed to heat treat it properly after the
>>>>> welding, and obviously messed up the finite element
>>>>> modelling. Those look like novice mistakes (I was performing stress creep
>>>>> cycle analysis using finite element models
>>>>> almost 50 years ago, and thought things had moved on a bit since then).
>>>>>
>>>>> It's not as if it's a revolutionary new design: the A train family has
>>>>> been in service for decades, and in service in
>>>>> the UK for over a decade. Yes, there are some new elements in the IETs,
>>>>> but surely Hitachi knows the design well enough
>>>>> by now to be able to evolve it without these embarrassing problems.
>>>>>
>>>>
>>>> Perhaps over confidence. Having designed similar but shorter carriages they
>>>> may not have considered that the longer vehicles might have had a strongly
>>>> non linear effect in some forces in critical areas. Modelling is only as
>>>
>>> So you're saying their models and engineers didn't take into account the
>>> effect of greater leverage forces? If they ignored something that fundamental
>>> what more complex factors did they skim over too?
>>
>> That’s entirely possible. If there’s an effect they didn’t anticipate
>> either their model may not have covered it or they may not have
>> investigated the conditions that cause it.
>
> There were two main differences with the IETs, compared to previous A
> Trains, and it could be that Hitachi didn't
> properly model the combination of the two:
>
> - Much longer carriages (the class 395 cars are 20m long, while class
> 800 cars are 26m long)
>
> - Heavy diesel gen-sets and fuel tanks mounted under the motored cars,
> which needed higher floors as a result.
>
> Most A Trains are Cape gauge commuter or regional trains, with maximum
> speeds of about 120-160 km/h, so the class 800
> power cars are much longer, much heavier, and run at much higher speeds
> than most A Trains (apart from the shorter,
> lighter class 395s).
>

It's not like Hitachi don't have experience of building longer or faster
trains, though; just not under the A-Train brand.

Anna Noyd-Dryver

Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> On Mon, 19 Jul 2021 10:35:31 -0000 (UTC), Sam Wilson
>> <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>
>>> <MrSpud_17VwhRsCh@59j51jh.tv> wrote:
>>>> On Sun, 18 Jul 2021 13:49:30 -0000 (UTC)
>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
>>>>>> Neil does have a very good point that an experienced train builder like
>>>>>> Hitachi really should be able to design/test new
>>>>>> trains that don't quickly develop expensive cracks in multiple places.
>>>>>> There are suggestions that they chose the wrong
>>>>>> alloy for one component, failed to heat treat it properly after the
>>>>>> welding, and obviously messed up the finite element
>>>>>> modelling. Those look like novice mistakes (I was performing stress creep
>>>>>> cycle analysis using finite element models
>>>>>> almost 50 years ago, and thought things had moved on a bit since then).
>>>>>>
>>>>>> It's not as if it's a revolutionary new design: the A train family has
>>>>>> been in service for decades, and in service in
>>>>>> the UK for over a decade. Yes, there are some new elements in the IETs,
>>>>>> but surely Hitachi knows the design well enough
>>>>>> by now to be able to evolve it without these embarrassing problems.
>>>>>>
>>>>>
>>>>> Perhaps over confidence. Having designed similar but shorter carriages they
>>>>> may not have considered that the longer vehicles might have had a strongly
>>>>> non linear effect in some forces in critical areas. Modelling is only as
>>>>
>>>> So you're saying their models and engineers didn't take into account the
>>>> effect of greater leverage forces? If they ignored something that fundamental
>>>> what more complex factors did they skim over too?
>>>
>>> That’s entirely possible. If there’s an effect they didn’t anticipate
>>> either their model may not have covered it or they may not have
>>> investigated the conditions that cause it.
>>
>> There were two main differences with the IETs, compared to previous A
>> Trains, and it could be that Hitachi didn't
>> properly model the combination of the two:
>>
>> - Much longer carriages (the class 395 cars are 20m long, while class
>> 800 cars are 26m long)
>>
>> - Heavy diesel gen-sets and fuel tanks mounted under the motored cars,
>> which needed higher floors as a result.
>>
>> Most A Trains are Cape gauge commuter or regional trains, with maximum
>> speeds of about 120-160 km/h, so the class 800
>> power cars are much longer, much heavier, and run at much higher speeds
>> than most A Trains (apart from the shorter,
>> lighter class 395s).
>>
>
> It's not like Hitachi don't have experience of building longer or faster
> trains, though; just not under the A-Train brand.
>

Perhaps not much experience of heavy, underfloor diesel gen sets?

In message <sd408i$dp5$2@dont-email.me>, at 13:55:30 on Mon, 19 Jul
2021, Recliner <recliner.usenet@gmail.com> remarked:

>> It's not like Hitachi don't have experience of building longer or faster
>> trains, though; just not under the A-Train brand.
>
>Perhaps not much experience of heavy, underfloor diesel gen sets?

Is it just the bi-modes which have experienced cracking? (Genuine
question, I've not seen it mentioned).
--
Roland Perry

Roland Perry <roland@perry.co.uk> wrote:
> In message <sd408i$dp5$2@dont-email.me>, at 13:55:30 on Mon, 19 Jul
> 2021, Recliner <recliner.usenet@gmail.com> remarked:
>
>>> It's not like Hitachi don't have experience of building longer or faster
>>> trains, though; just not under the A-Train brand.
>>
>> Perhaps not much experience of heavy, underfloor diesel gen sets?
>
> Is it just the bi-modes which have experienced cracking? (Genuine
> question, I've not seen it mentioned).

The cracks detected so far are mostly in the early trains which have done
more mileage, which are all bimodes. But Hitachi apparently expects all the
26m long vehicles to need repairs, but not the 24m EMR vehicles.

<MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
> Tweed <usenet.tweed@gmail.com> wrote:
>> <MrSpud_pw@245n.co.uk> wrote:
>>> Sure, but all this can be and should have been modelled and frankly its
>> basic
>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>
>>> that neither the engineers or the modelling computers forsee this.
>>>
>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>> it charges so much for them that it's probably still in the bkack.
>>>
>>> More than likely.
>>>
>>>
>>
>> You have a touching faith in modelling……..
>
> If you ever fly in an airliner you'd better had too. Or did you think they're
> still designed on boards by men with rulers and set squares?
>
>

New planes go through quite an extensive test programme. They don’t go from
model to passenger flight. I’ve no issue with CAD and simulation, but
simulation does need validation.

Tweed <usenet.tweed@gmail.com> wrote:
> <MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> <MrSpud_pw@245n.co.uk> wrote:
>>>> Sure, but all this can be and should have been modelled and frankly its
>>> basic
>>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>>
>>>> that neither the engineers or the modelling computers forsee this.
>>>>
>>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>>> it charges so much for them that it's probably still in the bkack.
>>>>
>>>> More than likely.
>>>>
>>>>
>>>
>>> You have a touching faith in modelling……..
>>
>> If you ever fly in an airliner you'd better had too. Or did you think they're
>> still designed on boards by men with rulers and set squares?
>>
>>
>
> New planes go through quite an extensive test programme. They don’t go from
> model to passenger flight. I’ve no issue with CAD and simulation, but
> simulation does need validation.

I’m not sure if it’s done for every aircraft, but many airliners had a
ground test airframe that was put through simulated flight cycles much more
quickly than any flying example, so they would see e.g. fatigue problems in
that long before they were likely in real life. That was certainly true
for Concorde and seems to have been true for the A380.

“Fatigue testing examines how the aircraft structure responds to stress
over a long period of time and during different stages of its operations,
such as taxiing on the runway, take-off, cruising and landing.

“To re-create these conditions, a combination of loads is placed on the
airframe and activated by 184 computer-operated hydraulic jacks. The A380’s
fatigue testing lasted 26 months up and was conducted to 2.5 times the
design service goal.”

<https://www.electronicsweekly.com/certification-and-test/general-certification-and-test/the-importance-of-fatigue-analysis-for-aerospace-airbus-a380-wing-rib-case-history-2012-07/>

Sam

--
The entity formerly known as Sam.Wilson@ed.ac.uk
Spit the dummy to reply

On 19/07/2021 17:49, Sam Wilson wrote:
> Tweed <usenet.tweed@gmail.com> wrote:
>> <MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>> <MrSpud_pw@245n.co.uk> wrote:
>>>>> Sure, but all this can be and should have been modelled and frankly its
>>>> basic
>>>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>>>
>>>>> that neither the engineers or the modelling computers forsee this.
>>>>>
>>>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>>>> it charges so much for them that it's probably still in the bkack.
>>>>>
>>>>> More than likely.
>>>>>
>>>>>
>>>>
>>>> You have a touching faith in modelling……..
>>>
>>> If you ever fly in an airliner you'd better had too. Or did you think they're
>>> still designed on boards by men with rulers and set squares?
>>>
>>>
>>
>> New planes go through quite an extensive test programme. They don’t go from
>> model to passenger flight. I’ve no issue with CAD and simulation, but
>> simulation does need validation.
>
> I’m not sure if it’s done for every aircraft, but many airliners had a
> ground test airframe that was put through simulated flight cycles much more
> quickly than any flying example, so they would see e.g. fatigue problems in
> that long before they were likely in real life. That was certainly true
> for Concorde and seems to have been true for the A380.
>
> “Fatigue testing examines how the aircraft structure responds to stress
> over a long period of time and during different stages of its operations,
> such as taxiing on the runway, take-off, cruising and landing.
>
> “To re-create these conditions, a combination of loads is placed on the
> airframe and activated by 184 computer-operated hydraulic jacks. The A380’s
> fatigue testing lasted 26 months up and was conducted to 2.5 times the
> design service goal.”
>
> <https://www.electronicsweekly.com/certification-and-test/general-certification-and-test/the-importance-of-fatigue-analysis-for-aerospace-airbus-a380-wing-rib-case-history-2012-07/>
>

Wasn't that one of the reasons why the latest twin engined Boeing
airliner was claimed to a be another 727 variant to avoid the more
rigorous testing that a new airliner would have had to undergone?

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 19/07/2021 17:49, Sam Wilson wrote:
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> <MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>> <MrSpud_pw@245n.co.uk> wrote:
>>>>>> Sure, but all this can be and should have been modelled and frankly its
>>>>> basic
>>>>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>>>>
>>>>>> that neither the engineers or the modelling computers forsee this.
>>>>>>
>>>>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>>>>> it charges so much for them that it's probably still in the bkack.
>>>>>>
>>>>>> More than likely.
>>>>>>
>>>>>>
>>>>>
>>>>> You have a touching faith in modelling……..
>>>>
>>>> If you ever fly in an airliner you'd better had too. Or did you think they're
>>>> still designed on boards by men with rulers and set squares?
>>>>
>>>>
>>>
>>> New planes go through quite an extensive test programme. They don’t go from
>>> model to passenger flight. I’ve no issue with CAD and simulation, but
>>> simulation does need validation.
>>
>> I’m not sure if it’s done for every aircraft, but many airliners had a
>> ground test airframe that was put through simulated flight cycles much more
>> quickly than any flying example, so they would see e.g. fatigue problems in
>> that long before they were likely in real life. That was certainly true
>> for Concorde and seems to have been true for the A380.
>>
>> “Fatigue testing examines how the aircraft structure responds to stress
>> over a long period of time and during different stages of its operations,
>> such as taxiing on the runway, take-off, cruising and landing.
>>
>> “To re-create these conditions, a combination of loads is placed on the
>> airframe and activated by 184 computer-operated hydraulic jacks. The A380’s
>> fatigue testing lasted 26 months up and was conducted to 2.5 times the
>> design service goal.”
>>
>> <https://www.electronicsweekly.com/certification-and-test/general-certification-and-test/the-importance-of-fatigue-analysis-for-aerospace-airbus-a380-wing-rib-case-history-2012-07/>
>>
>
> Wasn't that one of the reasons why the latest twin engined Boeing
> airliner was claimed to a be another 727 variant to avoid the more
> rigorous testing that a new airliner would have had to undergone?
>
>

737, not 727. All models of the 737, even the current MAX model, are
treated as variants of the original 1968 model, which has the further
'benefit' that they are tested to comply with the less stringent rules from
the mid-1960s.

On 19/07/2021 20:10, Recliner wrote:
> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> On 19/07/2021 17:49, Sam Wilson wrote:
>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>> <MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
>>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
>>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>>> <MrSpud_pw@245n.co.uk> wrote:
>>>>>>> Sure, but all this can be and should have been modelled and frankly its
>>>>>> basic
>>>>>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>>>>>
>>>>>>> that neither the engineers or the modelling computers forsee this.
>>>>>>>
>>>>>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>>>>>> it charges so much for them that it's probably still in the bkack.
>>>>>>>
>>>>>>> More than likely.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> You have a touching faith in modelling……..
>>>>>
>>>>> If you ever fly in an airliner you'd better had too. Or did you think they're
>>>>> still designed on boards by men with rulers and set squares?
>>>>>
>>>>>
>>>>
>>>> New planes go through quite an extensive test programme. They don’t go from
>>>> model to passenger flight. I’ve no issue with CAD and simulation, but
>>>> simulation does need validation.
>>>
>>> I’m not sure if it’s done for every aircraft, but many airliners had a
>>> ground test airframe that was put through simulated flight cycles much more
>>> quickly than any flying example, so they would see e.g. fatigue problems in
>>> that long before they were likely in real life. That was certainly true
>>> for Concorde and seems to have been true for the A380.
>>>
>>> “Fatigue testing examines how the aircraft structure responds to stress
>>> over a long period of time and during different stages of its operations,
>>> such as taxiing on the runway, take-off, cruising and landing.
>>>
>>> “To re-create these conditions, a combination of loads is placed on the
>>> airframe and activated by 184 computer-operated hydraulic jacks. The A380’s
>>> fatigue testing lasted 26 months up and was conducted to 2.5 times the
>>> design service goal.”
>>>
>>> <https://www.electronicsweekly.com/certification-and-test/general-certification-and-test/the-importance-of-fatigue-analysis-for-aerospace-airbus-a380-wing-rib-case-history-2012-07/>
>>>
>>
>> Wasn't that one of the reasons why the latest twin engined Boeing
>> airliner was claimed to a be another 727 variant to avoid the more
>> rigorous testing that a new airliner would have had to undergone?
>>
>>
>
> 737, not 727.

Doh! Always get those two confused! Not seen a 727 in years, are there
any still flying?

All models of the 737, even the current MAX model, are
> treated as variants of the original 1968 model, which has the further
> 'benefit' that they are tested to comply with the less stringent rules from
> the mid-1960s.
>

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 19/07/2021 20:10, Recliner wrote:
>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>> On 19/07/2021 17:49, Sam Wilson wrote:
>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>> <MrSpud_i3hlVA4c@duyjxeglvbef.org> wrote:
>>>>>> On Sat, 17 Jul 2021 16:19:11 -0000 (UTC)
>>>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>>>> <MrSpud_pw@245n.co.uk> wrote:
>>>>>>>> Sure, but all this can be and should have been modelled and frankly its
>>>>>>> basic
>>>>>>>> engineering. It doesn't say a lot about Hitachis railway engineering division
>>>>>>>
>>>>>>>> that neither the engineers or the modelling computers forsee this.
>>>>>>>>
>>>>>>>>> Any unreliability or maintenance issues cost Hitachi, not the customer, but
>>>>>>>>> it charges so much for them that it's probably still in the bkack.
>>>>>>>>
>>>>>>>> More than likely.
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> You have a touching faith in modelling……..
>>>>>>
>>>>>> If you ever fly in an airliner you'd better had too. Or did you think they're
>>>>>> still designed on boards by men with rulers and set squares?
>>>>>>
>>>>>>
>>>>>
>>>>> New planes go through quite an extensive test programme. They don’t go from
>>>>> model to passenger flight. I’ve no issue with CAD and simulation, but
>>>>> simulation does need validation.
>>>>
>>>> I’m not sure if it’s done for every aircraft, but many airliners had a
>>>> ground test airframe that was put through simulated flight cycles much more
>>>> quickly than any flying example, so they would see e.g. fatigue problems in
>>>> that long before they were likely in real life. That was certainly true
>>>> for Concorde and seems to have been true for the A380.
>>>>
>>>> “Fatigue testing examines how the aircraft structure responds to stress
>>>> over a long period of time and during different stages of its operations,
>>>> such as taxiing on the runway, take-off, cruising and landing.
>>>>
>>>> “To re-create these conditions, a combination of loads is placed on the
>>>> airframe and activated by 184 computer-operated hydraulic jacks. The A380’s
>>>> fatigue testing lasted 26 months up and was conducted to 2.5 times the
>>>> design service goal.”
>>>>
>>>> <https://www.electronicsweekly.com/certification-and-test/general-certification-and-test/the-importance-of-fatigue-analysis-for-aerospace-airbus-a380-wing-rib-case-history-2012-07/>
>>>>
>>>
>>> Wasn't that one of the reasons why the latest twin engined Boeing
>>> airliner was claimed to a be another 727 variant to avoid the more
>>> rigorous testing that a new airliner would have had to undergone?
>>>
>>>
>>
>> 737, not 727.
>
> Doh! Always get those two confused! Not seen a 727 in years, are there
> any still flying?

The last scheduled passenger flight was as recently as January 2019:
<https://thepointsguy.co.uk/news/worlds-last-passenger-727-just-flew-for-last-time/>

But if you really fancy a ride with a difference on a 727, then your luck
is in, if you have $7000 to spare:
<https://www.gozerog.com/home/>

<https://www.businessinsider.com/zero-gravity-airplane-g-force-one-boeing-727-2020-10>

I believe there are still a dozen or so cargo 727s still in service, but
probably only sporadically.

On Mon, 19 Jul 2021 19:10:19 -0000 (UTC)
Recliner <recliner.usenet@gmail.com> wrote:
>Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> Wasn't that one of the reasons why the latest twin engined Boeing
>> airliner was claimed to a be another 727 variant to avoid the more
>> rigorous testing that a new airliner would have had to undergone?
>>
>>
>
>737, not 727. All models of the 737, even the current MAX model, are
>treated as variants of the original 1968 model, which has the further
>'benefit' that they are tested to comply with the less stringent rules from
>the mid-1960s.

I bet that little fact never appears in the sales brochure.

<MrSpud_pfydu8@ane2dwrvghbm2c4bd8p94.edu> wrote:
> On Mon, 19 Jul 2021 19:10:19 -0000 (UTC)
> Recliner <recliner.usenet@gmail.com> wrote:
>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>> Wasn't that one of the reasons why the latest twin engined Boeing
>>> airliner was claimed to a be another 727 variant to avoid the more
>>> rigorous testing that a new airliner would have had to undergone?
>>>
>>>
>>
>> 737, not 727. All models of the 737, even the current MAX model, are
>> treated as variants of the original 1968 model, which has the further
>> 'benefit' that they are tested to comply with the less stringent rules from
>> the mid-1960s.
>
> I bet that little fact never appears in the sales brochure.
>
>

The sales brochure (aimed at the airlines, not the pax) showed off that
existing 737 pilots could convert to the latest model with minimal
retraining (a short, self-administered online course lasting one to three
hours). This obviously benefited the airlines, as the pilots could
transition to the new model very quickly, at minimal cost and almost no
down-time. Unfortunately, it turned out that Being had missed out some key
information in the short intro course...

<https://edition.cnn.com/2019/03/22/us/max-8-boeing-self-administered-courses-lion-air-ethiopian-airlines-intl/index.html>

<MrSpud_pfydu8@ane2dwrvghbm2c4bd8p94.edu> wrote:
> On Mon, 19 Jul 2021 19:10:19 -0000 (UTC)
> Recliner <recliner.usenet@gmail.com> wrote:
>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>> Wasn't that one of the reasons why the latest twin engined Boeing
>>> airliner was claimed to a be another 727 variant to avoid the more
>>> rigorous testing that a new airliner would have had to undergone?
>>>
>>>
>>
>> 737, not 727. All models of the 737, even the current MAX model, are
>> treated as variants of the original 1968 model, which has the further
>> 'benefit' that they are tested to comply with the less stringent rules from
>> the mid-1960s.
>
> I bet that little fact never appears in the sales brochure.
>
>

It's not exactly a secret, though.

Anna Noyd-Dryver