Posts by user "M2dude" [Posts: 257 Total up-votes: 1 Page: 12 of 13]¶

Jane-DoH
OK here we go:

1) The first shock was generated from the top lip of the intake

2) A second shock is generated from the fwd ramp hinge

3) A third isentropic fan shock is generated from the progressively
curved section of the fwd ramp

4) A 4th shock was generated fron the bottom lip
5) A terminal shock system is generated by the coalescence of
still supersonic and now subsonic air at the upper section of the ramp
area.



Hopefully these two diagrams will help. The first hand illustration above gives the 'theoretical' shock pattern and the second below gives an illustration of practical flows within the inlet. Both assume critical operation at Mach 2.


I hope all this blurb helps


Best regards
Dude

CliveL
Clive, thank you so much for your correction; I will ammend this diagram in my files immediately.
(As always you are of course 100% on the bal. And what do aerodynamisits know about aerodynamics anyway ).

Best regards
Dude

Ahhhh... the famous Reheat Capability Indicator. (Yes that was its official title). I seem to remember that before we did the modification to fit the 'RCI' in the late 1970s, the guys used to set an INS CDU thumbwheel as a memo to whether the take-off was a 'go-er' or a 'stopper'.
It seems a million years ago when we fitted this high presicion lump of alluminium. (Hang on a minute, it WAS ).

Best regards
Dude

And a thank you from me CliveL for your superb explanations regarding intake shock structure. It can not be over-emphasised just what an amazing achievement the Concorde engine/intake combo was. I can think of no other design in the world, before or since, civil or military, where a supersonic engine/intake marriage gave such incredidable levels of performance, stability and predictability. I just regard myself as being extremely fortunate to have been able to 'play with' this amazing kit for so many years and see what design excellance really is. (And at least pertly understand it too).

Jane-DoH
One of the real beauties of the Concorde intake was that it was completely self-startiing, and so unstarts as such were never heard of.
Regarding the vibrations thing, here is my post #80: I seem to remember that Rolls Royce proposed a solution of their own, whre the right hand pair of engines would rotate ant-clockwise (viewed from the front) rather than the clockwise norm for just about any 'Roller' that I can think of. Although this would have completely solved the vibration problem, and was great business for the folks at RR in Patchway (just about doubling the required number of engines) it was a pretty lousy idea if you were an airline and required a much latger holding of spare engines.

OMG Clive yes, sorry about that. I remeber it well now, I just did a search and posted up my original.

For take-off reheat was selected (armed) on all 4 engines together, and certainly not in pairs. (As was stated previously, once 81% N1 was reached the reheat light-up sequence was automatically initiated). You would not wind up on the brakes either, the carbon brakes were extremely sensitive to overtorquing. For transonic acceleration however you are quite right about the 'burners in pairs' bit.

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).

CliveL
The RELIFE programme had already taken the aircraft to 8,500 cycles, and the escence of RELIFE 2 had already been agreed when the maggots pulled the plug in late 2003. My own personal guess is that we'd now be looking at RELIFE 3 within a few years if we were still operating. It always really was a case of 'how long's a piece of string' as far as how long the aeroplane could be kept flying.

She was a a test airframe only, although in circa 1985/86 we did look at modifications that would bring her up to production aircraft standard. The modifications required to the powerplant alone (mainly engine and intake control logic and management) were truly massive, as well as other things like engine instrumentation and other systems' control management. The total cripler however was the cost of a TOTAL RESKIN of the forward fuselage section (Component 30, made at Brooklands). The production series aircraft had a thicker skin here, and we were told that the CAA insisted on this being done as part of any conversion to airliner standard. Costs of around \xa330 were being banded about for bringing the entire airframe up to production aircraft standard. Also of course she had an MEPU when flying rather than a HYRAT for emergency power and of course a large flight test observers position.
I worked on 202 personally quite a bit during the mid to late 70's, but she never remotely 'felt' like a real production aircraft. Even aircraft 204 (G-BOAC) in her pre-route proving days was a radically different beast. (The OAC post route-proving modifications although at system level were quite extensive, these were miniscule in comparison to the differences between 202 and what we like to call 'the REAL Concorde'. Don't get me wrong, 202 did some absolutely stirring work in terms of route-proving and certification trials, and the restoration done at Brooklands is most impressive indeed, but she is and always was, nothing other than a test aircraft. She was no more a production airframe in reality than the pre-production aircraft 102, and I'm afraid that anyone thinking that she is anying other than this is truly deluding themselves my friend.
I'm sorry if this reality is dissapointing steve-de-s, but if you want to see a Concorde that is truly representative of what the aircraft was really all about I suggest that you pop up to either Manchester or East Fortune. (The only airliner museums in the UK now open to public viewing). The Manchester exhibit in particular is truly superb and beautifully kept by some great people, and shows you exactly what Concorde, THE AIRLINER was actually like, rather than just seeing a test specimin. (A superb specimin 202 indeed she was, but this is ALL she ever was, a test specimin).

Best regards
Dude

Well in that case you are obviously right I suppose and BA, BAe (as it was) and the CAA were all wrong as far as component 30 goes. And everything that I was told at Fairford was wrong too. I guess it goes to show I suppose that all these bodies can be wrong.
There were several semi-structural and 'heavy' system components that were robbed by BA (I removed some stuff myself in the mid 80's and early 90's), but the fact remains that there were massive system differences that could never be reconciled by simple 'mods'. The fact also remains that she was a 5100 variant aircraft and not a 5101/5102 variant (or a 100 series aircraft either) and was significantly D-I-F-F-E-R-E-N-T to the 'real' aircraft, the airliners. I was THERE and I SAW the differences myself enough times for goodness sake, and the fact remains she was NEVER an airliner and never had any real prospect of being one. (But as I said before, she was a wonderful TEST specimin and did some stirling work). Brooklands really has a lot to offer the visitor as an exhibit I suppose but if you want to see Concorde THE AIRLINER then you really need to go elsewhere. Manchester in the only place where you can now see an intact production series Concorde in the UK and as I said before is NOW lovingly cared for by some brilliant people.

Regards
Dude

CliveL (And ChristiaanJ)
Sure can Clive. These are the BA 5102 numbers, Air France 5101 numbers were corespondingly identical chronologically.: G-BOAC - 5102-01. G-BOAA - 5102-02. G-BOAB - 5102-03. G-BOAD - 5102-04. G-BOAE - 5102-05. Although G-BOAG (G-BFKW) and G-BOAF (G-BFKX) were originally Variant 192 (British Unsold) aircraft, these correspondingly became 5102-06 and 5102-07. I wonder if anyone here remembers G-BOAF doing her pre-delivery flying at Filton registered as G-N91AF? I remember when I was at Filton doing one of my Concorde type courses in 1980, and there was good old Foxy Lady with her 'Branniff' registration. She was re -re-registered to G-BOAF prior to delivery to BA.

The Component 30 skin thickness issue was not relevant for RELIFE 2 ; you and I know that the major 'skin' issue here was the centre fuselage crown area. The issue of Component 30 was a 201/202 issue only. (Assuming that the French had the need/desire/capability of adding another airframe to their fleet.
And sorry everyone about the \xa330 cost of converting 202 into an airliner, I meant (dumb ass that I am) \xa330 MILLION.

Best regards
Dude

I personally doubt very much if the Emergency Pilot would be the 'way in' for the sidestick input. EFC ROLL commands were inputed from the SFC computer to the Autostab computers as 'stab demands' and therefore drove the MIDDLE and OUTER elevons only for roll. To make matters worse, if your test flight was really 'exciting' and you found yourself at any time at Vmo + 20 KTS, roll control would be through the middle elevons ONLY. I'm with CliveL in that the most likely scenario would be for the demand would feed via a D/A converter somehow. (It would be great to find out though).
I would have thought that the whole venture was a proof of concept by SFENA for future implementation in the Airbus family. This excersise would have been both costly and highly complex at system level, any other reason would really have been quite daft.

Best Regards
Dude

gordonroxburgh
It matters not I'm afraid Gordon. I would not have thought that anyone would design ANY flying control system, experimental or otherwise, that does not have full potential authority in all axis. As we do not know what the PROPOSED flight regime was, on the part of SFENA and Aerospatiale,we also can not assume that any particular manoeuvr would not have been considered. (But as I said before, it would be great to find out the whole story).
The limited authority for roll autostabilisation (and hence Emergency Flight Control) was of course a very deliberate piece of design. (You could test the Emergency Pilot on the ground at ADC Test 2 (Which simulated several seperate overspeeds, including Vmo +20) and when you put in a roll demand (against some resistance), only the MIDDLE elevons deflected. It really looked wierd on the ICOVOL as well as outside the aircraft.
(To any chaps or chapesses who are not aware, above Vmo+20 KCAS, a system known as OUTER ELEVON NEUTRALISATION was invoked, where any input demand to the outer elevons was met by an automatic equal and OPPOSITE input, that of course completely neutralised the demand, giving a zero OUTER elevon deflection).

Best regards
Dude

I've been away 'cruising' for a few weeks (lecturing about Concorde) and thought it was time I popped back into this wonderful forum.
There were a few questions regarding ground running Concorde, so here are some 'facts' as far as I recall (Wrinkled old brain permitting).

Concorde was ALWAYS ground run in the detuners at the BA Engineering base at Heathrow, with the parking brake ON. (Save idle runs on the ramp after, say, replacing a PNC actuator etc. on departure. The required high power nozzle trim run could be deferred until the aircrafts return to LHR). Sadly I can confirm that the Concorde 'Hush House' was being demolished when I was last over the engineering patch a few weeks ago, and is probably all gone now.

The detuner chocks were like nothing else you could imagine. They were HUGE steel affairs that needed wheels to be wound down in order to move into position (took a couple of guys at least to move). Once in position forward and aft of the undercarriage, the wheels would be retracted and these 'chocks' would be tension chained together. Believe me, nothing was going to move these suckers!!

Engines WERE NOT run in symmetrical pairs, but the adjacent engine always was run at idle power. The reason for this was so that there was airflow over the T1 probe of the adjacent engine, a winding in this being used by the alternate engine control lane if needs meant it might be required if the main lane failed during the engine run. The way that the aircraft was tethered meant that symmetrical high power running was not any sort of issue.

We were very mean too. In the summer the hangar doors of TBK opposite would invariably be open during the day, the challenge was to see how long it took for us to make them close the doors to shut out the din. (Like I said, Concorde engineers were mean ).

Good to be back
Best regards to all
Dude

As I recall, they referred to this research project as a CCV (Controlled Configured Vehicle) design study. It would be great if we could get this confirmed, but they talked about subsonic drag reductions of 10 to 15% by flying (not taking off!!) with a far more aft CG than the norm. The 'system' I seem to remember, as a result naturally commanded some down elevon, which increased lift. As the aircraft could then fly with less alpha, I guess this is where the drag reduction comes from. (Clive, I wonder if you could find out through one of your contacts if this was true?).
I'd still personally like to know how the sidestick was integrated into the flying control system, I've been thinking and can not now believe that sidestick inputs could be simply input to the flying control system 'at resolver level'. Remember that the concept of the FBW system on Concorde was that resolvers were utilised as simple 4 wire synchros, and the pitch and roll axis utilised a CX/CDX/CT chain, which produced the error signal to the ESA's in the Autostab computers. Using a sidestick completely breaks up the chain, and my guess is that a seperate digital unit contained the flight rules which were summed against PFCU CT position and sidestick input would have been necessary. It is possible then that an analog output from this 'box' could be fed to the Autostab Computer ESAs and hence drive the elevons. I'm probably completely wrong, but I'd surely still love to know the truth. As you say Clive, ideal stuff for Concorde 2.

Best regards
Dude

Thanks for the info Clive, now all is explained. (And I take your point about the elevon deflection).

Best Regards
Dude

Concorde Profitability
Ahhh that question again. Just concentrating then on matters on the UK side of the English Channel. Prior to the Paris crash, BA was making a very healthy profit indeed on it's Concorde operation. There were some blots on the horizon that had to be overcome (Relife 2, SFAR regulation implementation, EGPWS and GPS navigation enhancement etc.) but all these things were 'doable' and under both study and disussion.
After the Paris crash came the horrible events of 9-11; around 40 regular BA Concorde passengers were tragically lost in the twin towers alone. When the aircraft returned to service in November 2001 the loads (and profitablity) were understandably taking a major hit, but as all times in her service life Concorde had the ability to weather the storm and was already bouncing back well. Unfortunately in 2003, due to some totally disgusting goings on, on the French side of the Channel, the aeroplane never got the chance to fully recover and BA services ceased in October of that year. (It is to the eternal shame of certain individuals on THIS side of the Channel that this French Disconnection was never challenged legally).
Concorde was only ever run (that is at least in the UK) for profit, but the hike in oil prices would obviously pushed up ticket prices significantly, and the massive economic downturn of last year would have certainly meant a temporary reduction in services. But in spite of all this, I firmly believe that Concorde would have weathered this storm, and would have been now earning those bucks for BA yet again.

John Hutchinson - The Wind Beneath My Wings
A superbly interesting read, written about arguably the most eloquent of all Concorde pilot speakers. One of lifes true gentlemen and a superb pilot, it is a long overdue biography, well done Hutch.

Best Regards
Dude .

Speaking as a fellow sentimental ol' bugger, Peter Benn's commentary 'delay' (a truly nice guy by the way) is a simple case of between Mach 0.98 and Mach 1.02 the displays only showed Mach 1.0. So that's where we get our delay from.
Mach 2 was a bigger 'lie'. Anytime you were above Mach 1.98 the displays would only show Mach 2. (I've been to Mach 2.1 on test fliights but the pesky things still only showed us Mach 2).

Best regards
Dude

Glad the Filton AF guys enjoyed their Concorde fix. (There is no other Concorde in the UK, bar none, that able to achieve this fix better than G-BOAC can ). As far as the gear door colours go, well the 'normal' colour is the light brown one that you describe, the green primer colour door is a replacement one. (As to when we did that replacement I really can't remember I'm afraid - Extreme Brain Fatigue ).
I'll have a closer look at that door when I'm next up in Manchester in 10 days.

Best Regards
Dude