I am certainly glad neither of them did. It resulted in a piece of engineering art.

I've been trolling these forums for many a year and this has been or hopefully will continue to be the most fascinating, absorbing and educational thread I have ever seen.

Thank you gentlemen for your insights. 👍

Hopefully you mean "trawling". We would not want the moderators to get the wrong idea!

Concorde AICU
 

I have flitted through the threads, and have a few comments that might be of interest.
There were no classified components in the AICU, however there was company confidential in that we did not want the competition to have our lead, also there was an American embargo on delivering equipment with the 5400 series TTL logic integrated circuits which were milspec and chosen for their environmental screening.
Some of the printed circuit boards were 8-layer.
The program was contained in 512 lines of 24 bit instructions.

Concorde AICU
 

Hi Christian,I was a development engineer at Filton working on the AICU at first but ending up in charge of avionics test.
So as far as your AICU is concerned - I have handled all the boards extensively.
I first worked on the "A" model - the first manufactured box, followed by "A bar" (logically, not "A").
These did not have the doghouse connector on the front, and in order to see what was going on in the program, we made a strobe unit hard wired to the digital boards, this was followed by the connector on the front and an AICU test box.
When first switched on the whole unit rattled at high speed as all the relays chattered.
I spent several days adding decoupling capacitors on all the boards.
The birds nest chassis wiring was chosen to prevent cross- talk.
This was at the start of 1972, but I can still remember a lot of it.
Someone mentioned a prom change at Casablanca, I carried out a prom change there just before the C of A flight.
I am a volunteer at the Bristol Aero Collection, and we have just received a drawing cupboard with the AICS drawings.
We are at the moment documenting archives. One of the volunteers is Ted Talbot who I used to work with, and has been mentioned in posts.
Feel free to ask questions, I may remember the answers!

consub,
Slightly amazed about your note re the 5400 series TTL being embargoed.
I pulled a random board from "my" AICU, and all of it is 5400 series, datecodes 71 and 72.
I hope you can tell us some more...
I've been sniffing round the boards, but I haven't found the CPU or the clock... and yes, I know the AICU dates from before the arrival of the microprocessor!

Concorde AICU
 

Hi Christian,I was a development engineer at Filton working on the AICU at first but ending up in charge of avionics test.
So as far as your AICU is concerned - I have handled all the boards extensively.
I first worked on the "A" model - the first manufactured box, followed by "A bar" (logically, not "A").
These did not have the doghouse connector on the front, and in order to see what was going on in the program, we made a strobe unit hard wired to the digital boards, this was followed by the connector on the front and an AICU test box.
When first switched on the whole unit rattled at high speed as all the relays chattered.
I spent several days adding decoupling capacitors on all the boards.
The birds nest chassis wiring was chosen to prevent cross- talk.
This was at the start of 1972, but I can still remember a lot of it.
Someone mentioned a prom change at Casablanca, I carried out a prom change there just before the C of A flight.
I am a volunteer at the Bristol Aero Collection, and we have just received a drawing cupboard with the AICS drawings.
We are at the moment documenting archives. One of the volunteers is Ted Talbot who I used to work with, and has been mentioned in posts.
Feel free to ask questions, I may remember the answers!

Quite true about 5400 ttl, you had to sign that it wouldnt be exported when you bought it, however no one ever checked. the us govt were very touchy about "state of the art" ics in those days, mind you 5400 was only 7400 that passed more stringent temp tests;)

@rodlittle

Not just more stringent temperature tests. 5400 was also tolerant of twice the variation in supply voltage as 7400 (+/- 10% rather than 5%) and came in ceramic packages with hermetic seals rather than post-molded plastic packages (which could, over time, allow fluids to reach, and corrode, the active components and/or bond wires).

Hi Christian,
We chose the components for their environmental tests, and all the AICS components were subjected to acceptance testing when received, which was a bit of a problem sometimes because the BAC goods inwards system was so slow that some of the expensive ADC/DACs that were not quite good enough were returned to Harris, but were out of warranty by the time they were returned. The embargo was not just the 5400 TTL I/Cs but all milspec. components.
Its stretching my memory, but AICU1 was the ADC board, 2-5 were the processor, 6-10 were the prom boards. There was a bought in board (AICU 17 I think) that was supplied by ?????, that processed the sensor unit data.
The AICS was filled with redundancy, as well as the obvious 2 AICUs per intake, and 4 sensor units, the program calculated the output data with dummy inputs - twice, and if these were correct, the proper inputs were used and the result was output to the doors. On the analogue bit there were two channels for each output and at the end one output was compared with the other and if different a fail was produced.
We haven't opened the plan chests with the AICS drawings yet.
As well as the 8 AICUs on G-BOAF, we have the prototype AICU that was used on the AICS systems rig.

Nice Vid of the old girl at Liverpool

Ted Talbot's book
 

Reading for a second time to see what I missed the first time.

On p86 he says 'It followed the idea of multi-vane auxiliary air inlets into history."

Anyone know the story on these inlets?

Thanks.

They were an attempt to avoid the mechanical complexities of the prototype double hinged 'barn door' combined dump door/auxiliary intake by having several 'blow-in' vanes set in the door which were locked when the door was operated as a dump door.
Had their own set of mechanical problems and the idea was abandoned in favour of a single blow-in door (production solution)

Article: Researchers now know why Concorde was doomed to fail
 

I think this article is pretty wacky but the source seemed legit (Duke University / University of Toulouse Professors writing in Journal of Applied Physics) so thought I'd put it out there for discussion. Caveat emptor!

Law of physics governs airplane evolution

Law of physics governs airplane evolution

Researchers believe they now know why the supersonic trans-Atlantic Concorde aircraft went the way of the dodo—it hit an evolutionary cul-de-sac. In a new study, Adrian Bejan, professor of mechanical engineering and materials science at Duke University, shows that a law of physics he penned more than two decades ago helps explain the evolution of passenger airplanes from the small, propeller-driven DC-3s of yore to today's behemoth Boeing 787s.

The analysis also provides insights into how aerospace companies can develop successful future designs. The Concorde, alas, was too far from the curve of these good designs, Bejan says. The paper appears online July 22, in the Journal of Applied Physics.[snip]

In the case of commercial aircraft, designs have evolved to allow more people and goods to flow across the face of the Earth. Constructal law has also dictated the main design features needed for aircraft to succeed; the engine mass has remained proportional to the body size, the wing size has been tied to the fuselage length, and the fuel load has grown in step with the total weight.

[snip] The chart shows how the ratio of mass to speed of animals follows the same general rules as airplanes. Note that the Concorde is way off of the historical trend.

http://cdn.phys.org/newman/gfx/news/...wofphysics.jpg

http://cdn.phys.org/newman/gfx/news/...wofphysics.jpg

It's a fascinating posit, and one for aviation nerds to discuss at length down the pub - I'll give it that!

The general trend follows, but he doesn't spend much time on external factors (such as the 747's degree of success being aided significantly by the tribulations of Lockheed's L1011 development and MD's reaction to the DC-10's flaws).

It's interesting that the article writer seized on the paragraph about Concorde to frame his article though - it's almost a footnote in the original journal piece!

This sounds similar to a parametric design process used at BAC Warton in '70s. Used data of size, weight, power, etc to predict features of future aircraft. No idea how far it went as I was flight test and this was in design dept, Explained by a colleague at the time.

Comparing subsonic jets with supersonic jets is comparing apples with oranges. They both grow on trees but there the similarities end.:ugh:

What this article shows is that the most efficient design will win out in the long run. Being the best in an evolutionary niche is no guarantee of long term survival. Being the fastest animal on earth doesn't help if there is no prey left to hunt. Having a slow metabolism that enables an animal to lie in wait for extended periods before ambushing unsuspecting prey works better. Or moving more slowly but capable of travelling large distances in order to find more food is also a successful strategy.

There will always be outliers in any system that appear to enjoy great success by specialisation, but in the long term the non specialist, adapt to anything creatures are the ones that survive.

Look at the types of cars people drive for an everyday demonstration of this fact. The majority of cars on the road are optimised to carry a reasonable load, at a reasonable speed and with reasonable fuel consumption. Evolutionary (economic) pressure has resulted in moderate increases in performance, comfort and safety, but we are not all driving around in cars that are hyper efficient and capable of 100mph+ performance while using a teaspoon of fuel per mile. We have gas guzzling monster 4x4 off road vehicles, exotic sports cars and small efficient city cars, but the majority of vehicles on the road fall into the distinctively average category.

If road surface conditions get much worse in the UK, then evolutionary pressure will drive up sales of 4x4 off road vehicles to cope with the atrocious driving conditions. Increased fuel costs will drive up sales of small efficient city cars where people don't need to drive long distances. Just what appears to be the current situation in the UK.

Efficiency trumps everything in nature and so it should in engineering. Get the most bang for your money and it is difficult to go wrong. Being in the top three of everything is far better than being first in one thing and bottom of the table in everything else. Specialisation is a poor long term survival strategy.

I'm not sure I buy that argument entirely. Yes, the non-specialist compromise design might capture a major chunk of the market. But that doesn't mean that the niche market doesn't exist: Monster cars are being sold for decades. So are RVs & bulletproof cars & gigantic mining earthmovers.

There's a tiny market for a gigantic transport plane or the behemoth seagoing barge that can transport mega machines. But doesn't mean that's a dead market or money can't be made there.

Perfect example of nonsense theory!
The geopolitical factors are completely ignored in order to make the analysis work.