Posts about: "Avionics" [Posts: 15 Page: 1 of 1]¶

Biggles78
Sorry Biggles78, I'd forgotten to answer your CofG query, so here we go: CofG was a really critical parameter on Concorde, being a delta, with no tailplane made it more so at take off speeds, and as we've previously said, was how we trimmed the aircraft for supersonic flight. CG was expressed as a percentage of the aerodynamic chord line. To get indication of CG you needed to know the mass of fuel in each tank; easy, from the FQI system. You needed to know the moment arm of each tank, (fixed of course). You then needed the zero fuel weight (ZFW) and zero fuel CG (ZFCG); these were manually input into the CG computers by the F/E, from load control data. The final parameter you needed was total fuel weight, again easy from the FQI system.
The 'normal' T/O CG was 53.5%, but in order to increase fuel weight (and hence range) an extra 'bump' was enabled to allow a max T/O CG of 54%. (CG was indicated on a linear gauge, with forward and aft limit 'bugs' either side of the needle. These bugs would move as a function of Mach and at the lower end of the speed range, A/C weight also). As the A/C accelerated, the limit bugs would move rearwards (with of course the rearward shifting centre of pressure) and so the fuel would be moved from the two front trim tanks 9 & 10 to the rear tank. 11. Once tank 11 reached it's preset limit (around 10 tonnes), the remainder of the 'front' fuel would automatically over-spill into tanks 5 & 7. (Once the fuel panel was set up, the whole process was controlled with a single switch). At Mach 2, the CG would be around 59%, the whole rearwards shift being in the order of 6'. As we said before, the 'final' CG could be tweaked to give us a 1/2 degree down elevon, for minimum drag.
I really hope this helps Biggles78.

Guys, back to the Airbus thing; My friend ChristiaanJ gave some really accurate insights, (he always does) but there is another legacy that carries on the this day; some of the audio warning tones were COPIED from Concorde into Airbus. (For example, the A/P disconnect audio is identical). I think this is great, and gives 'our' aircraft a lasting everyday legacy.

As far as the fly by wire goes, Concorde had a relatively simple analog system, with little or no envelope protection (Except at extreme angles if attack). As has been previously poted before, production series test aircraft 201, F-WTSB, pioneered the use of a sidestick within a new digital fly by wire Controlled Conviguration Vehicle sytem, with envelope protection and attitude rate feedback. (This evolved into the superb system known and loved by the Airbus community). It is a really bizaar twist of fate that the Concorde FBW system has more mechanical similarities to the system used in the B777 than Airbus. (Mechanically similar at the front end, with an electric backdrive system moving the column in A/P mode; Concorde being backdriven by a hydraulic relay jack).
As a final piece of irony; the Primary Flight Control Computers on the B777 are designed and built by GEC Marconi Avionics in Rochester Kent, now BAe Systems. This is the same plant where Elliot (becoming Marconi and finally GEC Marconi Avionics) developed and built the UK half of the AFCS computers. Isn't this aviation world strange?
Galaxy Flyer
Your inputs here are great, and I'm sure appreciated by all. (I assume from your name that you were a C5A pilot. While I was in the RAF on C-130's, our Lockheed rep' used to supply us all with company magazines, that were full of stuff on this new (it was then) giant of the sky. I fell in love with it there and then).
Anyway, back to Conc': The decel' positions were carefully worked out and adhered to; the aim was to be subsonic to within (I think) 50 nm of the east coast. I'll wait for one of my Concorde pilot friends to confirm that here, but i think I'm correct. I do have a fond memory of one flight out of JFK; we were temporarily 'held' by Boston ATC to Mach 1.6 (and at around FL440) because of an Air France Concorde heading for JFK. We saw this guy above us, at around FL580 on a near reciprical , doing Mach 2, screaming straight over the top of us. We were excited by this amazing spectacle, and so were the AF crew over the VHF ('you never boomed us, did we boom you?'). But the most excited person of all was this guy in Boston ATC. ('I've never seen anything like it guys, your two blips whistled over each other on my my screen like crazy').
Stliton
As far as the F/D noise levels were concerned, once the nose and visor were raised, it was as if someone had switched off the noise . The main source of noise up there was just the equipment cooling, and that was not bad either. It was, in my view, little noisier up than most subsonics. (But not the 744, where you are so far away from all the racket ).
Ozgrade3
You're making us blush here; thanks for your comments, I think we are just trying to share some of our experiences (and 'bit's we've picked up over the years).
From my perspective, I did write some stuff used by our pilots, AF even got a copy or two I think.

Thanks from the peanut gallery seconded.

If anyone's looking for a good home for Concorde avionics, perhaps they might consider the National Museum of Computing at Bletchley Park, which has many fine examples of British electronics (LATCC donated an old ATC system) and is making a good fist of curating them.

I know the people there quite well, and would be delighted to put anyone in touch.

R

twochai
It is wonderful that you have such fond flying memories of Concorde;in the pre-911 days there was a fairly liberal open door policy for flight deck visits (Although all passengers were made to feel really special, it is so great that the guys had you up front for so long on that flight. You just never lose those sort of memories, I know).
The Radiation Meter was an interesting addition to Concorde's collection of avionics kit. It was primarily designed to detect solar proton, as well as neutron radiation, (the detector element lived behind the fwd r/h wardrobe as I remember and was a total pain in the 'you know where' to get at). The indicator displayed the dose rate in millirems/hour, with amber and red triggers, triggering a master alarm. (The amber was a mere caution, whereas the red was a warning. I can't quite remember any figures, but a descent was required with a genuine red warning. I think I'm correct in saying that no such descent was ever required, at least in the UK). There was a huge amount of concern initially about crews long term exposure to radiation, after all there is a fairly linear relationship between solar radiation and altitude. In reality however Concorde crews received far less radiation than subsonic crews; although the dose rates may have been higher, the sector times were a fraction of a lot of the subsonic routes. (Even a subsonic LHR-JFK is WELL over twice the sector length). Nuisance ambers were not uncommon, a certain 'facility' in Berkshire would often register as the aircraft over-flew, as well as MANY years ago, Three Mile Island itself. I remember that there were long term plans to replace the radiation meter with a portable 'carry on' device that was being trialled. (Spares for the detector were becoming very difficult to obtain).

Dude

Something I think I hinted at before, was how much the two Concorde prototypes differed from the aircraft that followed, even from the pre-production aircraft.

Wherever you look... the cockpit, the visor, the engines, the tail, the avionics, other systems... the prototypes were a first "iteration", designed and built to prove the concept.

The real development was done on what were the real "development aircraft", the pre-production and first two production aircraft (even if 01 / G-AXDN was a bit of a hybrid, retaining the short tail and the early engine nozzles).

I hope sometime the story; of how different were 001 and 002 from those that followed, will go on record before it fades into the mists of time.

CJ

landlady, your recollections of JC are so typical of what most people that knew him had. He was an astonishing character, an extremely talented flyer with a wicked wit to match. I remember many years ago, while travelling as 'passenger' with him on a charter flight, I was in the rear cabin during taxi, when there was a minor problem on the flight deck. Over the PA came these dulcet tones 'OY, AC/DC (due to me having an avionics 'bent', this was John\x92s nickname for me), GET YOURSELF UP HERE NOW'. With my street cred' totally blown away, a (then) young and highly embarrassed me slunk his way up to the flight deck, trying not to look at the 100 or so faces looking at me in total mirth.
I think everyone that ever came into contact with John misses him enormously, like all of his friends I know I do.
Please keep posting landlady, your memories are priceless to us all.

Dude

coobg002 ,

I'm not an aircraft designer, just an avionics engineer with an aeronautical engineering background, so my answer can only be partial...

Pity you cannot ask the question directly to "Clarence" Johnson, because he used both solutions for two of his best-known Mach 2+ designs...

The F-104 had indeed a very small, very thin, straight wing.
The SR-71 had a wing shape not totally unlike Concorde; admittedly the wing shape itself was more a delta, but the 'chines' of the forward part of the fuselage played an important role.


I would say.... every design is a compromise.
You don't start with a good-looking shape, you start with a specification.

In the case of the F-104 it was for an interceptor, something simple and fast , with a (relatively) limited range.
So you chose a big engine, you stuck a cockpit at the front, and you added the smallest straight wings that would do the job.
Not exactly ideal at low speed... the F-104 had huge "blown" flaps and even so it was still pretty "hot" during approach and landing.
As to what to do after an engine failure.... the procedure for a dead-stick landing was in the manual, but generally the "she flies like an angel, but she glides like a brick" would prevail, and you'd punch out.

In the case of the SR-71, much like Concorde, it was the 'spec' that was totally different.
Long-range supersonic cruise (hence space for fuel in the wing was prized), but also acceptable low-speed handling.
Think of the repeated air-to-air refuelling for the Blackbird, or the subsonic sectors in a typical LHR-JFK flight for Concorde.

So for anything that can still take off and land at an acceptable speed and perform well subsonically when needed, yet cruise at Mach 2 or Mach 3, the ogee/delta wing has turned out to be the best compromise.

CJ

Can somebody explain to a "Volts and Amps and Ohms ancient" what "hotstreak injection" is/was (without getting scabrous)?

Many thanks for that story, M2dude, and no problem understanding it that one.

Same here.
Purists be damned.
Concorde wasn't created 'ab nihilo', in a vacuum, as it were.
So, placing her squarely in the aviation world of the time should be part of the thread and the story.

In my own field (avionics) both TSR-2 and Concorde are almost "snapshots" of technology at a given time, a technology which was changing very rapidly.

I may go and rabbit on about that some more, one of these days, but describing what happened in the avioncs/electronics field is always more difficult than the purely mechanical, engine and structure progress.

CJ

PS A few years ago I had a chance to have a close look at some of the TSR-2 electronics in the East Fortune (Scotland) museum.
IIRC a lot of it was Ferranti.
It was an eye-opener as to how much technology had already changed from TSR-2 to Concorde.

Another pie-in-the-sky Q for you guys:

Concorde carried 100 fare-paying pax.

Hence, If you were looking to redesign Concorde today, to be more cost effective, you would I assume look to increase passenger loads?

Would this purely be a case of sticking everything in the photocopier and hitting the 'enlarge 150%' button? or could you have got away with expanding the cabin width or lengthwise without totally ruining the performance envelope? (a total redesign of the structure notwithstanding)

and which way would you expand? cabin width or length? or both?

Also, I assume a lot of the heavy analogue avionics kit would be replaced with lighter, microprocessor-controlled kit, giving more space and weight for fuel?

The Olympus engines replaced with more efficient ones given the march of technology?

So basically, if the British & French governments had another brain-fart and decided in 2011 to build Concorde2, what would you keep? what would you junk? and what realistically would we end up with in terms of pax numbers, performance, range, etc?

(you have an unlimited budget but need to make the thing a better economic prospect than if just presented with a fleet of de-mothballed Concordes).

Cheers,
Mike.

Not a lot! Well maybe the pitots.

I spent a lot of time on this in the 80s, but really one has to assume that Sir Lancelot put the Philosopher's Stone in the Holy Grail and buried it under the (other) end of Finnegan's rainbow and that YOU KNOW WHERE TO DIG!

When I left it the project looked a lot like this photograph that Christiaan found and posted on another site:



About 200 PAX, area ruled fuselage, new wing planform, flaps maybe, canard/foreplane, new shorter/lighter intake design,separate nacelles, new materials (probably not composites), digital avionics etc. but most of all a revolutionary new engine concept that nobody has invented yet. This engine has to produce lots of quiet thrust for airfield operation (low specific thrust) and lots of thrust with low frontal area for cruise (high specific thrust). Any takers?

Cheers

CL

I so remember the BAe AST images from the 1980s, I always thought what a potentially nice looking aeroplane she was. I guess that vastly improving the L/D & T/W ratios could go quite a long way to improving the operating economics, but the noise issue was always going to be the crippler. (I know that they were looking at a 'leaky' version of the OLY593, ie. a very low bypass ratio, but this of course would still not really cut the mustard as far as noise goes). I guess there are no current takers then
Clive, you really surprise me when you say you don't think that composites would be used from a future SST, is there a material reason for this? (I'm curious because being of a simple avionic brain, I always assumed composites would be used. But if anyone knows this stuff, you certainly would Clive ).
To answer Mike-Bracknell's original query, as far as avionics goes we can really go to town. For her age Concorde had some truly amazing aircraft systems, for instance the flying controls. To enable mechanical control (both FBW channels failed) there was a highly complex and heavy mixing unit under the rear floor. (To mix pitch and roll pilot mechanical demands into differential elevon demand inputs). This of couse would have to be done away with, as well as the relay jacks and replaced with a pair of side-sticks. (See posts on previous page). A 2 crew operation would obviously be the way to go, but neither desirable or possible in my view when Concorde was designed. A triplex or quadruplex flying control system (possibly even integrating autoflight) would replace the Concorde collection of several analog boxes with a very small handful of lightweight digital units.. The powerplant control will have major weight savings, just take a look at this lot. 8 Engine Control Units, 4 Bucket Control Units, 2 Nozzle Angle Scheduling Units, 4 Reheat Amplifiers, 8 AICUs, 4 Air Intake Sensor Units and a single Air Intake Test Unit could potentially be replaced by just 4 multi-channel EEC type units. (On subsonic aircraft the EECs are mounted on the engine itself, not sure if that's a good idea for an SST, given the operating environment. Air Data and Navigation systems take a major simplification and weight saving, the 3 INUs and 2 ADCs (All of them straight from the 'rent a hernia' store as far as weight goes), could be replaced by a single ADIRU and a SAARU. The fuel indication/management side of things (2 FQI packs, 2 level switching packs and 3 CG computers) would probably be replaced by a single Fuel Processing unit. Ahhhh perchance to dream

Best regards
Dude

Hi again Jane-Doh. Self starting meaning (at least to my non-aerodynamicist avionics infected brain) that the shock system will establish itself perfectly without specific movement of the variable surfaces. Similarly it will not experience the phenomonem (unstart) where the whole shock system will be violently expellled to the extent that it can not tbe safely re-established without changing both the engine power setting and the variable surface position. (This whole thing being the 'train wreck' phenomen ).
That was interesting stuff about the P38, I must admit I'd not heard that one. (Makes sense I suppose though, provided that the engine can be easily be re-positioned in such a way).

Interesting... but unlikely.

The first question : why? The old analogue systems still worked well.

Second question : who? There were only 14 aircraft in service... who would paid the immense bill for redesign and recertification?

A third question : we know one of the major factors in the 'end of service' decisions were related to the rapidly increasing maintenance costs (as billed by Airbus). A complete upgrade of the avionics (digital, glass cockpit, etc.) would not necessarily have resulted in less maintenance costs.... it would still have been for only 14 aircraft.

In the end, the only real and 'visible' avionics upgrade was the installation of TCAS, and that was only because it was made mandatory.

CJ

In actual fact BA looked very seriously in the mid 1980s at a limited glass cockpit, where the primary flight and engine instruments would be replaced by and EFIS/EICAS setup, ala Boeing 757. Studies were quite advanced, the main cited advantage was 'reduced cost of ownership.' It seems that the reason it never went any further was, now here's the irony, 'increased training costs. (You have to remember that the 757 was the only glass cockpit BA had at the time, with nothing much else on the horizon).
There would certainly needed to be other upgrades avionics wise, in the fullness of time, but the glass cockpit was not really top of the list. Glaring requirements were improved navigational accuracy, as well as EGPWS together with predictive and reactive windshear protection. (Although to really get the most out of this an EFIS type system is crucial). We (BA) were already looking at both EGPWS and the replacement of the DELCO Carousel 1VAC INS. The Litton 92 had been suggested early on, as it was the only laser INS available with a GPS card fitted, but it is possible that given time an IRS with separate MMR interface would have been used. (This of course now requires an FMC, with a potentially rather involved VNAV profile). As far as EGPWS (and GPS navigation), the main problem was going to be 'where to put the darned GPS antenna' up there on the fuselage crown, but this was being looked at right up to 2003. Providing there was an adequate way of displaying the warnings, predictive windshear protection would have been a breeze, as the Bendix RDR4B radar system (itself retrofitted in the mid 1990s) had the PWS capability merely disabled on Concorde). As Concorde was a highly profitable enterprise for BA during the vast majority of her service life, it is my view that natural avionics updates, such as those described, would have found their way onto Concorde given enough time. (EGPWS, GPS NAV as well as PWS protection would almost certainly have been on board by now).

Best regards
Dude

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!

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!