Posts by user "M2dude" [Posts: 257 Total up-votes: 1 Page: 10 of 13]¶

SUPERSTAB
To hopefully further clarify, this was controlled from the SFC computer and was a two part mix:
1) With Vc < 270 KTS the AUTOSTAB pitch damping was increased as a function of pitch rate and pitch rate DOT, Vc DOT and corrected (wing) incidence. Maximum possible demand limited to 8\xb0 nose down.

2) With Vc < 140 KTS and alpha/alpha rate greater than 19.5\xb0 (this itself would generate the 'wobbler' or 'unmistakable warning') a 4\xb0 nose down signal is generated over a 1 second time constant.

I hope the enclosed diagram helps to put it all in place.

Best Regards
Dude

EXWOK
Clive, I think we need your help here. I was also told, both while I was at Fairford and during one of my two ground school courses at Filton in the early 80s, that the lateral stiffeners (underneath the wing just inboard of the Rib 12 area) were added to reduce outer wing flexure and in themselves gave us a performance penalty. Can you shed any light Clive?

Best regards
Dude

CliveL
Tee hee, can't get away with anything here anymore Clive Yes, of course (as ever ) you are correct; it was technically a hybrid system: The servo loops, in terms of ramp and spill door demand signals and resolver position feedback signals etc. DID use conventional analogue drive and servo amplifiers within the AICU, it was the massive arithmetic computation UP-STREAM of these that was digital. I always used to like to refer to the AICS as 'an analog front end with a digital brain'. But that's just me .
But as you say Clive, none of the control law sophistication (including the synthesising the intake face total pressure and local Mach numbers from mainline aircraft raw air data) would have been possible using analog computation.

Best regards
Dude

Mr Vortex
The Thrust recuperator (or thrust recovery nozzle) was fitted to the outlet of #1 (that is, left hand) forward discharge valve (outflow valve in Boeing speak) only. It was a variable 'louvre' type nozzle that would progressively close between 3 and 7.5 PSI diff'. The idea was to direct pressurisation outflow air directly backwards along (theoretically) the aircraft centre line (That at least was the theory). I read somewhere that at max diff' (10.7 PSIG) it would recuperate some 600 lb of thrust. HOWEVER, this system was fitted to the #1 system only (1 & 2 were used on alternate flights) and there was no performance penalty when the thing was not working. Here are a couple of diagrams.

Best Regards
Dude

I took this one over the Atlantic, of G-BOAF, BA002 at Mach 2 FL 560 from G-BOAD FL 480 Mach 1.9 (test flight) in July 2003. (Mach 3.9 closing ).

Best rgards
Dude

CliveL
The dual pressurisation systems each had two discharge valves, one just aft of the nose undercarriage and the other at the rear of the aircraft. The forward valves would carry away the electronics rack discharge air, where the aft would vent the underfloor area. There was no common discharge point Clive, no. The #2 system forward valve would just throw the air overboard, without the sophisticated 'nozzling' of the #1 system. So I guess we have to go figure just how useful the thrust recuperation system was, but I personally think that EXWOK got it right.
ChristiaanJ
The stiffenersd did not go over the bathtub joints my friend, , they were inboard.

Mike-Bracknell
Unfortunately Mike your photo is a little too far outboard to show them. We need to go a little more inboard and slightly further aft. I've been through my photos and can't yet find one. (Honest CliveJ, it is the truth, they DO exist ).

A very happy Christmas to everyone here; Personally I am working right through Christmas AND New Year (darned aeroplanes)
Dude

ChristiaanJ
Yippeeeee we have a winner. Coffin Dodgers photo of my poor old G-BOAA shows the stiffeners perfectly. (I was starting to think that I had gone even more bonkers than usual, and was imagining the things ).

Best regards to all
Dude

First of all a hearty 'Happy New Year' to all our readers. As I've been 'away' for a week or so, I hope you will all indulge me as I answer a few posted points. (I totally agree with what Bellerophon said about restricting our posts to the 'techy' and nostalgic stuff, so will not respond to anything else here) .

CliveL
I accept and understand of course Clive that this was a difficult issue to predict with any certainty, it was just a shame that's all, that the Type 28 never fully lived up to its promise and potential. However, the one aspect of the SNECMA design that was very poor indeed was Secondary Nozzle system integrity. Throughout the operational life of Concorde, there were almost more operational disruptions due to short-fallings here (bucket runaways) than any other issue. It was only near the very end of Concorde's operational life that modifications were finally forthcoming from SNECMA to address this.

Poornamechoice
I am so sorry to dispel this particularly charming story, but there were absolutely no keys as such for Concorde, Sorry (But I am so glad that you are enjoying this wonderful thread).

ChristiaanJ
Oooooh speaking for myself (and I suspect a whole lot more of the BA Concorde familly) there is a void alright. Having lived with the 'lady' day in, day out for almost 30 years (up to November 2003) there was an absolutely yawning chasm left for me personally. (The world of the blunties is just not the same.. just a whole lot slower ).
What is gratifying though, is the enormous amount of interest that there still is for Concorde; both in this thread and in the world at large. I guess she lives on after all.

These pictures of 101 etc are absolutely marvellous; I really like the 'sexy' wing shape photo's. One little unique point about 102; she flew with a different intake control system to any other Concorde, being an 'improved' Ultra Electronics analog system. (Although the intake itself was aerodynamically the same as the later aircraft). Never really understood why our French friends chose this particular path with this aircraft. (Perhaps CliveL can shed some light on this??).
Very best regards to all.

Dude

Clive & Christian
Gentlemen, I think you will find that 102 did indeed have a totally 'unique' analog intake control system. Not only were the RDCUs (not AICUs in this case chaps) totally different, there were major architectural changes over the prototype system too. Also, although the basic intake structure was the same as 101 and all subsequent aircraft, there was still the prototype approach to local pressure sensing adapted, ie. Intake face total pressure P∞ sensed directly via the infamous 'magic holes' rather than using digitally synthesised values based on mainline aircraft manometric probe, total (pitot)pressure. As 101's intakes only went 'live' in mid-march 1973, I assumed that maybe they (AS) wanted an operative intake system from the outset on 102 when it first flew in January of that year. What puzzled me was why they went for this seemingly enhanced (and expensive) analog system on 102 and not the original system. (As 102 used a production type intake, I guess that they would have to have at least made some changes to the control system ; there was no exotic double hinged 'Dump Door', but the far simpler and elegant 'Spill Door' with integral Aux' Inlet Vane that was known and loved by us all). Rumour had it that AS still wanted to pursue the 'magic holes' solution and were dead against the decision to go digital. (This particular decision was taken in October 1970, which makes the 102 AICS route seem all the more strange).

And ChristiaanJ; what you guys achieved with the MAX CLIMB/MAX CRUISE was nothing short of remarkable. Just about the most exotic (and complex) autopilot mode that I've ever seen, that solved so MANY problems. (Still the only A/P mode I've ever seen where the Autothrottle is engaged in a speed mode at the same time as the AUTOPILOT ).
Best regards

Dude

atakacs

Quote:

Just wondering was that the maximum speed "in" the design ? I understand that "the higher & the colder = the faster" was the key to the performance and that the Mach +/- 2.0 cruise was implied by limiting altitude to FL 600 in order to mitigate cabin depressurization consequences. I guess there where also thermal issues but was, say, Mach 2.2 @ FL700 "warmer" than Mach 2.0 @ FL600 ?

Really an answer for CliveL, but I'll have a go. The short answer to your question is 'oh yeah, big time'. Total temperature varies with the SQUARE of Mach number and static temperature. Depending on the height of the tropopause itself as well as other local factors, there can be little or no significant variation of static temperature between FL600 and FL700. The 400\xb0K (127\xb0C) Tmo limit was imposed for reasons of thermal fatigue life, and equates to Mach 2.0 at ISA +5. (Most of the time the lower than ISA +5 static air temperatures kept us well away from Tmo). In a nutshell, flying higher in the stratosphere gains you very little as far as temperature goes. (Even taking into account the very small positive lapse above FL 650 in a standard atmosphere). As far as the MAX SPEED bit goes, Concorde was as we know flown to a maximum of Mach 2.23 on A/C 101, but with the production intake and 'final' AICU N1 limiter law, the maximum achievable Mach number in level flight is about Mach 2.13. (Also theoretically, somewhere between Mach 2.2 and 2.3, the front few intake shocks would be 'pushed' back beyond the lower lip, the resulting flow distortion causing multiple severe and surges).
On C of A renewal test flights (what I always called the 'fun flights') we DID used to do a 'flat' acceleration to Mach 2.1 quite regularly, as part of the test regime, and the aircraft used to take things in her stride beautifully. (And the intakes themselves were totally un-phased by the zero G pushover that we did at FL630). This to me was an absolute TESTAMENT to the designers achievement with this totally astounding aeroplane , and always made me feel quite in awe of chaps such as CliveL.

Quote:

Also wondering what was the max altitude ? Was high altitude stall (for the lack of a better word) ever experimented during tests or training ?

Well the maximum altitude EVER achieved in testing was I believe by aircraft 102 which achieved 68,000'. As far as the second part of your question goes, not to my knowledge (gulp!!) but perhaps CliveL can confirm.

Shaggy Sheep Driver
So glad you are enjoying the thread, and absolutely loved the description of your flight in OAD and your photo is superb. I don't think it is possible to name a single other arcraft in the world that could be happily flown hands off like this, in a turn with 20\xb0 of bank at Mach 2. (One for you ChristiaanJ; The more observant will notice that we are in MAX CLIMB/MAX CRUISE with the autothrottle cutting in in MACH HOLD. Oh, we are in HDG HOLD too ).
Now for your question A very good question. The anti-skid system used a fixed simulated nose wheel rolling speed Vo signal as soon as the undercarriage was down and locked, this was confirmed by the illumination of the 8 'R' lights on the anti-skid panel. The illumination of these lights confirmed that there was full ant-skid release from the relevant wheel, due to there being of course zero output initially from the main gear tachos but this simulated Vo output from the nose gear tacho. The Vo signal therefore ensured that the aircraft could not be landed 'brakes on' (all the main wheels think they are on full skid) and that there was anti-skid control pending lowering of the nose-wheel. As the main wheels spin up on landing, their tacho outputs now start to back off the Vo signal, and braking can commence. As the nose leg compresses, the Vo signal is removed and the Nose-wheel tachos(their were 2 wired in parallel) spin up, their output will now replace the Vo signal, and full precise anti skid operates.
As far as your air conditioning question goes, you needed an external air conditioning truck to supply cabin air on the ground. Not needed in the hangars of course, but come departure time if these trucks were not working, then the cabin could become very warm/hot place indeed (depending on the time of year). Oh for an APU
Best regards

Dude

A really wonderful photo.
As you say, as the main gear tachos spin up the brakes no longer they think that they are in full skid and can be applied. The only electronic 'protection' as such is the anti-skid itself via that Vo signal in the anti-skid unit (known as the S.P.A.D. box). This would still help control and limit main wheel braking. However the professionalism of my friends such as EXWOK, NW1 and Bellerophon was the REAL protection here. I will let one of them explain the normal braking procedure on landing.
Best regards

Dude

OK, here is a more unusual photo, but it's not as bad as it looks. It's a photo I took of OAD in 1994 during pushback in IAD. Occasionally if there was an excess of fuel lying in the bottom of the combustion chamber you used to get about 3 or 4 seconds of rather scary looking flames coming out of the jet pipe. It was never a problem, but looked quite spectacular (especially at night )





Best regards

Dude

Shaggy Sheep Driver
I personally agree about that photo, YUCH!!

Now about the cabin pressure thing: The pressurisation system would control to a MAXIMUM differential of 10.7 PSIG. Now at 60,000' the static pressure is 1.04 PSIA and at that altitude we would not QUITE be able to hold a cabin altitude of 6000', more like 6,200-6,300'. This is because 6000' altitude corresponds to a static pressure of 11.78 PSIA, giving us a diff' of 10.76 PSIG. Still as near as dammit mind, and for the MAJORITY of Atlantic crossings 6000' was fine. Such a 'civilised' cabin pressure was just one of the 1000 reasons that you never 'felt' as if you'd just flown over 3000 miles in Concorde.
Here is a diagram of the pressurisation panel.



The idea was that you selected a desired cabin altitude and the system would control to maintain that altitude all the way up to max diff. You could control the rate of presurisation too, to minimise popping ears etc. (Personally I always found Concorde particualarly good in that respect). There is one minor goof in the diagram, in that the discharge valve position indicator show both systems in operation. You only ever had one of the two systems in operation (via the SYS1/SYS2 selector switches). The only exception to this was on the ground when both systems were powered (and both sets of valves fully open).
Best regards

Dude

OK, here is a photo that I took at Fairford in November 1976. I'd just had my very first Concorde flight on a brand new G-BOAD, and took this flight deck photo in the hangar later that afternoon (the doors are open hence the late afternoon Cotswold sky. The point of this rather poor (sorry guys, I was young for goodness sake) photo is to look at just how subtly different the 1976 flight deck WAS.



The first thing I know EXWOK and BELLEROPHON will (maybe) notice is that originally OAD had a 'normal colour' electroluminescent light plate on the visor indication panel. (If I remember rightly (it was a million years ago chaps) when this one 'stopped lighting' we could not get a replacement and had to rob 202 (G-BBDG) at Filton; this one being the same black development aircraft colour that OAD has to this day.
The OTHER first thing that you may notice is the Triple Temperature Indicator on the captains dash panel. (The first officer had his in in similar position). These got moved around (twice in the end) when TCAS was installed in the mid-90's. It was amazing just how much equipment got moved around over the years, in order to 'shoe-horn in' various bits of extra equimpent.
The cabin altimeter here fitted just above the #1 INS CDU also got moved (to the centre consul) when the FAA 'Branniff' modifications were embodied later in the 70's. It's spot got occupied by a standy altimeter mandated by the FAA but this was removed after Branniff ceased flying Concorde; the cabin altimeter returning to it's former home. The REALLY observant will notice that there is neither an Autoland Ca3/Cat2 identifier on the AFCS panel (glued on by BA at LHR) or the famous and precision built 'Reheat Capabilty Indicator' flip down plate fitted to the centre dash panel a few years later by BA.
Also not shown here, as they were buyer furnished equipment also fitted at on delivery LHR, are the two ADEUs (Automatic Data Entry Units, or INS Card readers). These were located immediatel aft of the CDU's and were used for bulk waypoint loading ('bulk' being 9, the most that the poor old Delco INU memory could handle). These were removed in the mid 90's when the Navigation Database was fitted to Concorde INUs, and bulk loading then was achieved by simply tapping in a 2 digit code. (Hardly the elegence of FMS, but still very elegent in comparison with the ADEU's, and worked superbly). A little note about these ADEU things; You inserted this rather large optically read paper data card into the thing and the motor would suck the unsuspecting card in. As often as not the ADEU would chew the card up and spit the remnants out, without reading any data, or not even bother spitting out the remnants at all. Removing these things FINALLY when the INUs were modified was absolute joy!!
ps. When G-BOAG (then G-BFKW) was delivered in 1980 it had neither any of the Branniff mods or ADEUs fitted. (Also the INS was not wired for DME updating). This meant that obviously she could not fly IAD-DFW with Branniff but also she could not do LHR-BAH either, because of the lack ADEUs. (You could not manually insert waypoints quick enough over the 'Med', or so the guys told me. So for the first few years good old FKW/OAG just used to plod between LHR and JFK. And plod she did, superbly. She never did get the ADEUs (not necessary thank goodness when the INUs got modified) but we wired in DME updating and so she could navigate around with the best of them.
My gosh I do prattle on, sorry guys.
Best regards

Dude

PS Welcome back Landlady, hope you've recovered from your fall XXXX

SpeedbirdConcorde
Hi again my friend. To further expand on CliveJ's superb explanation: Mechanical control inputs were fed to each of the 8 Powerd Flying Control Units (PFCUs), but in electronic signalling (either Blue or Green) these inputs were de-clutched at the PFCU input lever. When Fly By Wire' signalling is not available, the mechanical inputs (which as CliveL quite rightly points out) are driven by the Relay Jacks, now are locked to the input lever and can now move the input jack of the PFCU (known as the spool valve) and subsequently cause the PFCU to drive the control surface. (The body of the PFCU moved, the main jacks were attached at each end to structure and so obviously did not move). Hopefully this diagram will help visualising the process a little easier:

The diagram shows Green & Blue hydraulics supplied but the electro-valves (opened by the respective FBW channel) are both closed. You can see that the mechanical input lever is 'locked' to the PFCU input lever which will drive the SPOOL VALVE directly. When FBW is enabled, either the Blue or Green (never both together) ELECTRO-VALVE are signalled open, the ensuing hydraulic pressure then pushing the input clutch upwards and disengaging the mechanical input. FBW demands are now fed to the respective SERVO VALVE which will hydraulically send the SPOOL VALVE in the desired direction.
The Relay Jacks could be considered to be a little like a PFCU (you had 2 RJs per axix) but instead of the servo valves being driven by the FBW system they were driven by the autopilot and instead of driving a control surface, they drove the control runs. In manual flight the input spool was driven via a mechanical input lever, which would drive the RJ spool a little like Mech' signalling drove the PFCU spool. In A/P mode the mechanical input rod was de-clutched \xe0 la PFCU, but (and here's the clever part) this input was locked to the body of the Relay Jack which when it moved, drove the pilot's control in sympathy. (Control column, yoke or rudder pradals). As the respective control(s) was moved by the Relay Jack, the corresponding FBW position sensor (resolver) would change position and generate the FBW demand. (As the surface moved there was a feedback resolver at PFCU level).
As far as the FBW channels themselves went; there were 2 electronic signalling modes, Blue and Green, sub-divided into 3 groups (Inner Elevons, Outer & Mid Elevons and Rudders). Each group was independently monitored, and a fault in say the Rudder channel alone, would result in the rudders ONLY changing lanes. NOW ( ), The normal control channel was BLUE, and if this failed you would drop the respective channel into GREEN and if this failed you would drop into MECH. The selector switches (1 per group) enabled you to select BLUE/GREEN/MECH in that order. If for some reason you were selected to GREEN, a failure of that signalling lane would not drop you 'up' into BLUE, but into MECH. Your switch would only be in this position if you'd had a problem with BLUE, however you would select this on pushback while you were testing the flying controls, otherwise you spent your whole life selected to BLUE. As far as BA went, I can never remember a time personally when all 3 groups dropped from BLUE to MECH, but very rarely you might get a fault that caused a single group to briefly drop to MECH. Just about one of the very few common mode failures to each of the 3 groups would be a failure of the respective FBW static inverter. This thing, which was rightly monitored up to the hilt, produced a 26 Volt 1800 Hz output. (1800 Hz was chosen as this is not a harmonic of aircraft mainline 400 Hz AC supply)
Best regards

Dude

NW1
Ahhh the Tech refresher days. Not being an EO it would not have been me, no. But the 'trainers' often used to come seek me out in the hangar and (over coffee, not beer I'm afraid) confer about various system quirks and nasties to use on you guys during the tech' refreshers. (So I guess can be blamed for a few of the 'stinkers', sorry ). And I definately know who you mean by describing him as a 'chatty' EO.... a truly great guy though.
Mech' signalling during decel'??, OUCH!! I would have thought that the 'supersonic dustbin lid' description would have been quite an accurate description of what must have been a very uncomfortable experience indeed. It was quite a vivid and scary description, I can just imagine trying to move the 3 switches up to BLUE from MECH and stabbing the reset buttons while your seat and the selector panel are seemingly going backwards and forwards, up and down in different directions!! . On the C of A renewal test flights I seem to remember that MECH was only tried fairly briefly at a very subsonic 300 KTS during the early stages of the flights, but even then it felt like the aeroplane was riding a sea of different sized golf balls and the outer wing sections seemed to flap about quite enegetically in a world of their own; it was pure bliss when we reset into BLUE. It really shows us all just how good the FBW and autostab really was, the fact that the aeroplane handled so beautifully throughout such an enormous envelope. Well done CliveL and ChristiaanJ and all you designer chaps. .
Now NW1, I bet you can still really do the flying control check in your sleep ( ), but 'Great times, great aircraft, great people' is certainly a marvelous way to sum up such an amazing time of our lives. I still feel honoured and very lucky to have been a small part of it all for so many years.
And as for March... Yes I will be there; see you on the 4th.
Best regards

Dude

Good to have you back here again Howie

Quote:

Really alternate side Ignitors? All RR aero engines I have worked on always sparked up both sides every time, well the Avon, Spey 202, RB199 & the Oly 20202 (Vulcan) and industrial Oly did. Would this have made a difficulty with starting logic?? Was there LH & RH Ignition selector switch maybe?

There was no automatic ignition selection logic as such built into the start sequence, but a manually selected L & R ignition selector switch. The reason of course to alternate L & R selection during starting was to detect otherwise dormant ignition failures if 'BOTH' was always selected. (Modern A/C with AUTOSTART do not have this problem, if an ignitor fails during the engine start sequence the other is automatically selected and an ignition status message is set on the lower EICAS screen). The ignition L/R selector switch was bypassed during engine operation by the auto-ignition system, where if the engine control unit detected a flame out (set at 58% N2) both ignitors would automatically fire up. The sequence would release onece the perceived N2 rose above 63%. The ignition system had several reliability issues, the first was the plugs themselves. Penetration into the 'can' was crucial; if it were more than about 130 thou', the tip would very quickly burn off. We soon learned that a penetration check was vital when fitting a plug and shims needed to be used to get the correct penetration. The other reliability issue was the ignition leads themselves; For the first 10 years of service they were a major pain until 'they' (Rolls-Royce) finally got it right. Also until Rolls modified the lead clipping, it could take 3 to 4 HOURS to change a lead. The dual channel HEIU itself was as good as gold, and seldom let us down, It was a very powerful 8 Joule 2KV beast, and you obviously treated it with utmost respect.

Best regards
Dude

ChristiaanJ
You young vandal you Christian. I'm just conjuring up the visual, a young ChristiaanJJ, vacuum cleaner hose in one hand and horizon in the other, the gyro whirring round at warp speed. (What voltage and frequency suction air did you use ? HAHAHA).
I seem to remember the Chipmunk used to use a cute little 'vaccy' gyro horizon. I pulled many of these apart during my RAF training. (Sometimes I even managed to get the odd one or two back together and working again).

Best regards
Dude

Brit312
The main problem with testing ignitors in the hangar was residual fuel. The LH ignitor sat right at the bottom of the can, and sometimes had a small puddle of fuel lying over it. This would produce a small 'whoof' of smoke out of the jet-pipe for about a second or two as the ignitors fired, but no more than that. The main danger was forgetting to trip the START PUMP C/Bs before you did the ignition check. If you did you had a guaranteed fire in the can (the pump would run as you know as soon as 'START' was selected and stayed running for 30 seconds after the start switch was returned to NORMAL) which was very messy (and scary as hell too). The only remedy was to grap a start truck, make sure the C/B is finally tripped and dry motor the engine until all the smokey stuff is gone. (It did no damage, but made a hell of a lot of smoke; the fire brigade were never best pleased). But provided the ignition checks were done correctly there was no ptoblem. (In nearly 30 years of doing ignition checks CORRECTLY, I never once saw a problem. Saw a few when people did forget to trip the start pump C/B however.
In any case as far as the 'ground engineers' doing the check of the ignitors, in my opinion if you are doing a pre-flight check, there is no point doing it unless it is pre-FLIGHT. Just about every other system on the aircraft got tested right up to when you boys arrived at the aircraft, but quite rightly you tested them again. (The whole point of 'us' testing systems was to pre-empting failures before they could impact the departure time).
If you even bothered to read what I wrote "But the 'trainers' often used to come seek me out in the hangar and .....confer about various system quirks and nasties....". I never suggested that anyone but the trainers themselves wrote the tech refreshers; but several of the guys (not you, obviously) waited 'til I was back from leave etc to ask away over coffee about some specific system QUOTE quirks and nasties UNQUOTE they figured I would know about and could use in their refresher.
Or perhaps you are suggesting that I am hallucinating or worse?

Dude

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