Posts about: "Microprocessor" [Posts: 13 Pages: 1]

Ozegrade3, Biggles78 and all,
I agree, the more of the history that we can write down somewhere, the better....
Just look at the "Did You Fly the Vulcan?" thread here on PPRuNe....

A chance remark by M2dude reminded me of something I meant to write about sometimes... and that has barely been mentioned in the various Concorde stories.
It's the huge gap between the prototypes on the one hand, and the pre-production and production aircraft on the other hand.

It's not just the visor, or the shorter tail.

In my own "field", the AFCS (autopilot, etc.), there was not a lot of similarity between the prototypes and their successors.
The prototypes were "proof-of-concept", designed in the early to mid 1960s.
The pre-production aircraft were designed in the end of the '60s and already close to the production aircraft in most respects.

Some of this difference was due to the very sudden and rapid evolution in electronic technology, with the arrival of the integrated circuit in particular.
The microprocessor - in a way just a large integrated circuit - didn't arrive in time... I don't think there was a single microprocessor on board Concorde until the days that they had to fit TCAS (in the '90s, IIRC).

I'll have to see how to do it.... maybe write it off-line and post snippets on here, then move it into a blog or suchlike?

ChristiaanJ
For once my friend you're not quite correct. The Plessey PVS1580 Aircraft Integrated Data System, fitted to all BA aircraft from mid' 1977 used a microprocessor in the data entry panel. In the mid-80's, a fault interrrogation module was fitted to the Engine Control Units; this used a 4 bit Intel 4004. Otherwise (as usual ) we agree.
I've some production series CG diagrams, that I will post here when I can find out how to do it......

You're right, M2dude, I should really have written that there were no \xb5Ps on board when she first went into service (1976), and that they only slowly filtered in afterwards.

Another example on the BA aircraft, of course, in full view of the pax, were the "Marilake" cabin displays that showed Mach, altitude, speed, etc. that replaced the earlier Mach-only displays, and where everybody just HAD to have their picture taken once at Mach 2. Each of the four displays (two up front, two at the back) had a micro-processor.

Not sure when those were first fitted.... it was during one of the cabin re-do's and livery changes.

I thought it might be nice to throw in a few trivia questions here to lighten things up. Most readers of this thread should be able to answer fairly easily; if necessary by checking back on some of the previous posts in the thread. (All questions relate to the BA fleet). Or there is always Uncle Google :
1) How many fuel tanks werer there on Concorde?
2) How many seats were there?
3) At what approximate altitude and KNOTS EAS was Mach 2 achieved?
4) Only one BA Concorde had three different registrations, what was it?
5) What was the maximum permitted altitude in passenger service?
6) How many wheels on the aircraft
7) How many flying control modes were there?
8) How many positions of nose droop were there?
9) What was the first microprocessor application on the aircraft?
10) How many main electrical sources were there?

Answers tomorrow

Dude

1) How many fuel tanks werer there on Concorde? - Lots
2) How many seats were there? - 12, the rest were freight bays
3) At what approximate altitude and KNOTS EAS was Mach 2 achieved? - Very high and very fast but NOT very very fast
4) Only one BA Concorde had three different registrations, what was it? - The one that was made at Filton
5) What was the maximum permitted altitude in passenger service? - Feet, metres or FL?
6) How many wheels on the aircraft - Just enough
7) How many flying control modes were there? - Fast, very fast and very very fast
8) How many positions of nose droop were there? - With the STOP or without?
9) What was the first microprocessor application on the aircraft? - Pacman (wild guess)
10) How many main electrical sources were there? - Tomato and BBQ

So what do I win?

As promised here are the answers to our trivia quiz.
Actually there were 14 (but if you are not necessarily a Concorde person, 13 is acceptable). There were '13 fuel tanks, numbered 1 - 11' as we used to tell all the visitors to the aircraft, (The wingtip tanks 5A & 7A making up the extra 2) PLUS a single small scavenge tank at the rear of the aircraft that was used to remove fuel from the vent lines and return this fuel via a transfer pump back to tank 3. (A fuel level sensor would trigger the pump with only 1 US Gallon of fuel in the tank). If the trim gallery became over-pressurised (ie tank 3 already full to the brim) an overflow relief valve (ORV) underneath the rear of the aircraft would open and dump the contents of the tank overboard. There was a flight deck indication if the scavenge pump was running in flight to give the crew an indication that a tank somewhere was probably over-filling and to take the appropriate action. There was one added goody about the ORV; If you were on the ground with the refuel door open and due to a refuelling overfill anywhere, fuel entered the scavenge tank, at 7 gallons the ORV would open and rapidly dump the fuel on the floor. For this reason a vent pipe and fuel drum was often placed underneath the ORV during high load refuels. If this was not fitted and you just happened to walk underneath the aircraft at the wrong moment during fuelling........
As a total aside to all this (or me going off on a tangent yet again) the fuel tanks themselves were gently air pressurised above 44,000' to around 2.2 PSIA. This was to prevent the beginnings of any boiling of the fuel in the tanks, due to the low ambient pressure/high fuel temperatures, causing pump cavitation. (Boiling itself could not occur much below 65,000'). A small NACA duct at the right side of the fin was used to supply the ram air for tank pressurisation, the two vent valves in the tail cone, one per trim gallery, closing off automatically at around 44,000', the pressure being controlled by a pneumatic valve, with full automatic over-pressure protection. OK sorry guys and gals, back to the answers:
This is the stinker.... there were 114 (although at entry into service there were 115!!). 100 passenger seats + 6 cabin crew seats + 5 flight deck seats (including the fold up seat in the aisle at the rear) PLUS 3 LOO SEATS (Originally 4 loos, the fourth loo being removed in the early 1980's).
50,189' and 530 KEAS, but we'll settle for anything around FL500 being correct.
Aircraft 216, G-BOAF, the last Concorde ever built. When 216 first flew in 1979 she was a variant 192 'British Unsold Aircraft' and was registered as G-BFKX. In late 1979, BA purchased the aircraft and it was subsequently converted to a Type 102 British Airways variant, and after modifications were complete, test flights were carried out from Filton under the registration of G-N94AF. This registration was to enable the aircraft to participate in the Braniff interchange between IAD and DFW, but when the Braniff Concorde adventure unfortunately ended in 1980, she was again re-registered to G-BOAF, this is how she was delivered to BA later that year.
Easy one this I hope; 60.000'. (As we've said before this limitation was imposed because of the dual window failure / emergency descent time consideration, not as a performance issue. On test flights 63,000' was routinely attained, and altitudes of up to 68,000' were achieved during development flying. (On her maiden flight, G-BOAB achieved 65,000' and Mach 2.04; the first British constructed Concorde to achieve Mach 2 on her maiden flight, and the ONLY one of the original five BA aircraft to achieve this).
Hopefully an easy one... there were TWELVE: 2 nose wheels, 8 main wheels and 2 tail wheels. (No, even I'm not nasty enough to include the wheels on the bar trolleys ). Oh, and there were 9 wheel brakes, one for each main wheel and as was mentioned in a previous post, a single steel disc brake for the nose wheels (the nose having a live axle), for automatic use during gear retraction only.
Three modes; Blue electronic signalling, green electronic signalling and mechanical signalling. I suppose we COULD be pedantic here and include the Emergency Flight Control mode where even with a jammed control column/control wheel, strain gauges (and Safety Flight Control Computers of course) would still enable you to control the elevons.
OK, three basically. Up (Duh!), 5 degrees for taxi/take off and low speed flight and 12.5 degrees for landing. As ChristiaanJ quite rightly pointed out in an earlier post, the prototype (and pre-production) aircraft landing position was 17.5 degrees of droop. (In my view the nose of the aircraft looked a little like an armadillo in this extreme configuration).
In 1977 the new digital Plessey PVS 1580 Aircraft Integrated Data System was progressively fitted to the BA fleet, this being the first microprocessor application on Concorde, this application being followed in several other systems during the life of the aircraft. The 'final' applications being TCAS and the superb retrofitted Bendix RDR-4A weather radar system.
No we are not including torch batteries and emergency lights etc. There were a total of seven main power sources: 4 x 60KVA AC generators, one per engine, a single 40KVA hydraulically powered emergency generator and 2 lead acid (or ni-cad in the case of G-BOAG) main aircraft batteries. (Not a terribly Re-Volting question I hope).

I hope this quiz was fun and not too perplexing to any of you guys.

Dude

I copied this off M2dude's post a couple of days ago, and tried to answer it all offline without cheating by looking up the answers elsewhere.

1) How many fuel tanks were there on Concorde?
LOL... 13.
I suppose that, for the same reason there was no row 13 in the cabin, somebody decided to name two of the tanks "5A" and "7A", rather than call the tail trim tank (named no.11) number 13.
Yes, I forgot the scavenge tank.
And since it was "BA Concordes only" I didn't want to add the hydrazine tank on the two preprod and the two certification aircraft.

2) How many seats were there?
Good question.
As Nick asked, which seats?
Nominally there were 100 pax seats in the cabin, although originally up to 127 were certified.
Five (three plus two jump seats) in the cockpit.
Cabin seats for the cabin crew.... I honestly don't know. Seven?
Wrong twice... six cabin crew seats, AND I forgot to count the loos!

3) At what approximate altitude and KNOTS EAS was Mach 2 achieved?
Roughly, FL500 and 530 kts.
But not being a pilot I had to check an instant on my flight envelope crib sheet, which I have at hand all the time.....
It seemed pointless to be TOO precise, because that assumed ISA and creeping exactly up the right edge of the envelope.

4) Only one BA Concorde had three different registrations, what was it?
Without looking it up, no idea. My guess is G-BOAF, with a white-tail reg, a "British" reg, and a pseudo-American reg.
IIRC, G-BOAG never had a pseudo-American reg, but I'm not sure without looking it up.
Brain not completely addled, then.

5) What was the maximum permitted altitude in passenger service?
FL600, as certified.

6) How many wheels on the aircraft?
Twelve, if you count the two Spitfire wheels at the back

7) How many flying control modes were there?
Four. Blue, green, mechanical and ... what did we call it? Control jam, CWS?
Ah, thanks, Emergency Flight Control. I always considered it as a separate mode, even if it was virtually never used.

8) How many positions of nose droop were there?
Four. 0\xb0, 5\xb0, 12.5\xb0 and 17.5\xb0 (the latter only on the prototypes, and purely mechanically, after removing a stop, on the other aircraft).

9) What was the first microprocessor application on the aircraft?
No idea... you (M2dude) mentioned a Plessey data acquisition system?
It was after "my time"...

10) How many main electrical sources were there?
Again, not sure... You're presumably are talking about primary sources.
There was an AC constant-drive generator on each engine.
Then there were two DC batteries.
And IIRC there was an AC generator running off the RAT hydraulic generator when pillar came to post.
Reading M2dude's answer, I suppose the emergency generator just ran off the hydraulics, not specifically off the RAT. Far more logical.

Nice one, M2dude!
And certainly not all trivia!

CJ

It is still difficult to grasp the fact that, with the one exception Christiaan has told us about, all of the control electronics in Concorde were analogue. Some of the little tweaks Dude has just alluded to in his reply about the nozzles and the relationship of compressor speeds, for example. Most of them would be relatively easy - relative is a huge word of course - if they were microprocessor controlled locally and sending/ receiving status and demand data to a bank of central computers. But to do it with analogue signals and controllers is mind boggling.

How all these signals and rates were calibrated and stayed calibrated is a mystery. The earliest scanners I worked on - mid seventies - were largely digital even then, but they did have quite big chunks of analogue circuitry. Virtually every process had to be self calibrating, most of them at the start of every scan. Even then drift was often a problem and sometimes problems would arise where drift exceeded the authority of the self calibration to manage it.

These pages of Concorde information are incredibly interesting, with more and more eyebrow raising revelations with each page. I still think that the nicest observation made was by Galaxy Flyer - an American, when many of his compatriots tend to the 'not invented here' school of appreciation.

And to compare Concorde with say the Apollo Project which inspired many a UK engineer, is praise indeed.

Roger.

Landroger
It always was a bit of a paradox; in terms of fuel price and environmental concerns, Concorde was about 5 years too late. But in ELECTRONICS terms she was 10 years too early. Bearing in mind that the first Intel 4004 was not even commercially available until 1971. When the decision was taken in late 1970 to 're-design' the analog air intake control system into a digital one, there was nothing to fall back on; a BAC custom guided missile processor (used I believe on both the Rapier and Sea Dart SAMs) had to be adapted. This processor was, as I've yawned on about before, comprised of multiple double sided PCBs completely stacked with TTL ICs. In spite of being a total antique and a dinasore (just like me ) this thing was really cutting edge technology at the time, even using a 64 bit data word. The AICS as again I've yawned on about before, was the WORLD's first commercial airborne digital control sysstem, but the Concorde analog stuff in fact worked pretty well indeed.

Galaxy Flyer
As always GF you make your point really well. As far as Concorde went, the very few American (Branniff) pilots who flew her thought she was totally amazing, and the American BA engineers at JFK and IAD absolutely adored the aeroplane.
And back to your 'charriot', the C5 has been a staggeringly successful aeroplane in terms of US service. and is still thriving (big modernisation programme underway). Not bad for an aircraft that entered USAF service in 1969!!!
Regards

Dude

There are several answers.....

One thing to bear in mind is that a lot of the computing was closed-loop, usually with several loops within loops.
Such closed loops do not require a very high precision or very narrow tolerances inside the loop.
In the Concorde AFCS, most of such computing was based on the use of +/-1% components (resistors, capacitors...) which were stable enough over their lifetime, and the ubiquitous LM101A integrated operational amplifier, which had low enough offsets and drift for the application. Occasionally we had to use the LM108 op-amp (more precise) and +/-0.1% components.

And where the analogue electronic computing was totally inadequate, we used... electro-mechanical computing, using synchros, resolvers and servo loops.

As M2dude says "in ELECTRONICS terms she was 10 years too early".
He's right.
She dates from that precise era, where technology changed from discrete components through the very first integrated logic circuits to mass-produced 'airworthy' logic and analogue circuits, but where the micro-processor was still in the future.
She was really the culmination of the "classic" era, before "digital" took over.

I could waffle on for hours... but don't know where to start?
Ask your questions, to let me know what you want to know.

CJ

Blue Wave
Although Marketing (bless 'em) and the usual 'Emperors New Clothes' brigade thought that this was wonderful, most of 'us' in the fleet thought that this was really quite a naff idea and would end up being a total annoyance to most regular Concorde passengers. The idea was that at Mach 1 a battery of blue lights would wash a single pulse from the rear to the front of the cabin. At Mach 2 you would get a double whammy blue light show to help ruin your concentration.

Marilake
I remember these 'improvements' to be embodied in 'project rocket' (as you say, pretty unreadable) but it would be interesting to look at the history of this thing. When it was first fitted in the mid to late 80s it proved itself to be total junk: Instead of using an off the shelf microprocessor design, Marilake Instruments decided to use a custom processor running from dedicated TTL/CMOS chips, it used a clumsy parallel instead of serial databus between the displays (stacks of extra wiring) ran red hot all the time (the toasty display units were surrounded by coats in the wardrobes to boot and also used a master/slave layout, where it the master (fwd right hand) display developed a fault you lost the whole shooting match. Just to put the cherry on the parfait, flight data had to be entered via a laughingly called 'hand held controller' that was fitted against the side of the C/B panel behind the captains seat. (This thing was so big that the supernumerary seat had to have restriction fitted to its fwd travel, to prevent the seat or occupier colliding with this monster). Now this thing, which was in reality a quite large LCD portable commercial computer terminal (it even ran BASIC!!), had to be initialised before every flight, and the crew had to input Baud Rates as well as all sorts of other bilge before the system would hopefully initialise. As often as not the system would lock up, and I'm quite sure that if this thing had not been tethered via a power and data cable, many a pilot or E/O would have tossed the thing out of the DV window!!. Reliability became so awful that eventually the whole system was disabled for about a year while Marilake were forced/coerced/threatened into a total system redesign. The final product, which ran nice and cool abandoned nearly all of the original hardware (no more master/slave arrangement either), utilised an ARINC 429 type databus and came equipped with new plasma displays which FINALLY worked rather well. The crap commercial computer terminal was replaced by a really neat data entry panel that was fitted on the left hand centre consul that worked pretty good from day 1. FINALLY the darned system worked.

Best Regards
Dude

Actually, formal proofs are used extensively in the design of microprocessors. The need for this is something the microelectronics industry learned the hard way after the Pentium I floating point division bug.

And, yes, there has been at least one case of a completely proved microprocessor design. The reason we haven't seen more is presumably because complete proof has turned out not to be necessary to achieve sufficient assurance of design correctness.

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!