Nothing In Particular

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Ray P
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Re: Nothing In Particular

Post by Ray P » Mon Jan 13, 2020 6:49 am

andrew Ivimey wrote:
Sun Jan 12, 2020 2:37 pm
Is anything? ::-----)
Well, we're not and our brains play tricks on us so even if it was identical we would probably say it wasn't the same.

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andrew Ivimey
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Re: Nothing In Particular

Post by andrew Ivimey » Mon Jan 13, 2020 8:39 am

Yes we do do that dont we.

And 'it' probably has changed anyway.

Here's a tale.

Do you remember the chocolate drops that Woolworth's used to sell back in the 60s - they disappeared late 70s. Bloody Common Market! Political correctness gone mad!! What does it matter if they weren't actually made if chocolate!!!

Sometime in the 90s I started to look for them - they couldn't really have vanished, banished to the developing world or further away even. I searched the U.K.s sweet shops big and larder but my quest remained frustrated. And then in the 21st century I was strolling down a little street in Whitby with my wife and I dashed into a sweet shop I had previously visited years before....

To cut a long story short I bought all they had and sure enough the chic drops were still being manufactured in Yorkshire, somewhere.

Having then eaten around 4kg of this delightful confection 'fairly' quickly ( I gave a few sweets away) I decided I had had a life's allowance of choc drops and no longer craved, fancied or desired, in the least, those lovely, as I remembered , far off youthful memories ever again.

But I'm sure they were the real thing.
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.

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ed
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Re: Nothing In Particular

Post by ed » Mon Jan 13, 2020 9:02 am

jack wrote:
Mon Jan 13, 2020 3:51 am
Really interesting article about the 737 MAX and the MCAS system written by a guy who is a pilot and longtime software engineer. Thoughtful and well written...

https://www.google.com/amp/s/spectrum.i ... r.amp.html
wow....My first thought was 'do not read this if you are planning an overseas holiday in the near future'. Then, rationally, I thought but the average person reading this wont worry because it applies to 737 max, and they are all grounded. But does it!

from an ex-pilot and ex-software engineer point of view I could point out a few journalistic features but I don't think the article is aimed at techies. I think the writer has done a superb job of illustrating the problem....but I wont' look forward to an invite to dinner, not with the size of his dinner plates.
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Nick
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Re: Nothing In Particular

Post by Nick » Mon Jan 13, 2020 11:11 am

jack wrote:
Mon Jan 13, 2020 3:51 am
Really interesting article about the 737 MAX and the MCAS system written by a guy who is a pilot and longtime software engineer. Thoughtful and well written...

https://www.google.com/amp/s/spectrum.i ... r.amp.html
Yep, all that information was out there around the time that Boeing were still claiming that the cause was not their fault.

I am a bit worried though with the view that you can achieve redundancy with two sensors.
Resistance isn't futile it's V / I.

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Mike H
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Re: Nothing In Particular

Post by Mike H » Mon Jan 13, 2020 3:23 pm

And this is page No. 737! How spooky is that
 
I have boxes and boxes full of components, but never the right ones!

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jack
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Re: Nothing In Particular

Post by jack » Mon Jan 13, 2020 5:11 pm

Nick wrote:
Mon Jan 13, 2020 11:11 am
I am a bit worried though with the view that you can achieve redundancy with two sensors.
It's a level of redundancy. The idea is that whatever happens, the human should be able to override the bitey dog...
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Nick
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Re: Nothing In Particular

Post by Nick » Mon Jan 13, 2020 5:31 pm

jack wrote:
Mon Jan 13, 2020 5:11 pm
Nick wrote:
Mon Jan 13, 2020 11:11 am
I am a bit worried though with the view that you can achieve redundancy with two sensors.
It's a level of redundancy. The idea is that whatever happens, the human should be able to override the bitey dog...
Yes, but it talks about the redundancy of two angle-of-attack sensors with the assumption that the human would provide the vote to determine which one had failed if they give different readings. But in heavy fog (for example) you are down to just the two sensors, as the human can't provide the final vote.

As you know I am sure, you can't detect a faulty sensor is you only have two. Its not about the dog. Now there may well be other sources of information that the system will use, but my point is that in his writing he is guilty (IMHO) of the same flawed reasoning that he points the finger at the Boeing developers for.
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Ray P
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Re: Nothing In Particular

Post by Ray P » Mon Jan 13, 2020 6:38 pm


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andrew Ivimey
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Re: Nothing In Particular

Post by andrew Ivimey » Mon Jan 13, 2020 6:43 pm

And Birmingham is getting radical with motor cars!
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.

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IslandPink
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Re: Nothing In Particular

Post by IslandPink » Mon Jan 13, 2020 6:49 pm

Bring it on !
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ed
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Re: Nothing In Particular

Post by ed » Mon Jan 13, 2020 7:39 pm

Nick wrote:
Mon Jan 13, 2020 5:31 pm

But in heavy fog (for example) you are down to just the two sensors, as the human can't provide the final vote.

As you know I am sure, you can't detect a faulty sensor is you only have two. Its not about the dog. Now there may well be other sources of information that the system will use, but my point is that in his writing he is guilty (IMHO) of the same flawed reasoning that he points the finger at the Boeing developers for.
that was one of the points I took issue with, but didn't voice in my post. If the 2 flow sensors are at odds with each other, and he did mention angle of attack was determined here(not always the case) then reference should be made to the artificial horizon, which also gives pitch as well as roll. Isn't this the third arbiter which he mentions is omitted from the test?

certainly in the cessna the artificial horizon is the life saver in limited vis, but I'm not sure what else they have on the 737. either way I'd like the pilot to be able to pull the plug on the computer.......but I'm a cable and rods kind of guy.

I have wondered on more than one occasion what would happen if I took my foot off in the fast lane of the motorway and the ecu took no notice. I had a diesel landrover that did the very same thing before flybywire was invented. Some previous owner had tied the air butterfly linkage assembly with bailing twine because the ball joint had broken. I was happily driving on the dual carriageway approaching Slough and took my foot off the accelerator when the beast started making a loud knocking sound and gaining speed....very scary...I only escaped by standing on the brake with all my weight and yanking the handbrake as hard as I could. It seems (I was told later) that the diesel pump was starved but the air kept on coming, so it started feeding on sump oil...go figure.

fly by wire? mmmm
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Nick
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Re: Nothing In Particular

Post by Nick » Tue Jan 14, 2020 11:14 am

and the ecu took no notice.
Probably much the same as a corroded throttle cable. Its not as if the older alternative was fault free as you said in the same post.

And I believe all cars are designed such that he breaking system can overpower the engine.

You also have a clutch in those cases.
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Ali Tait
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Re: Nothing In Particular

Post by Ali Tait » Tue Jan 14, 2020 12:18 pm

It’s a known fault with modern diesels that the engine can “runaway”, the engine will burn the engine oil to run.Usually results in over revving until the engine destroys itself. Rare but it happens.
Image[/img]

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shane
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Re: Nothing In Particular

Post by shane » Tue Jan 14, 2020 7:00 pm

For all our cyclists.

Beautifully engineered, but I don’t think I could cope with the enormity of the potential disaster.


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jack
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Re: Nothing In Particular

Post by jack » Tue Jan 14, 2020 7:16 pm

shane wrote:
Tue Jan 14, 2020 7:00 pm
For all our cyclists.

Beautifully engineered, but I don’t think I could cope with the enormity of the potential disaster.
It's a bomb under your meat and two veg 😱
Nick
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