Concorde question

[M2dude]

speedbirdconcorde

Regarding the rather important role of the elevons on Concorde where there any failures during her time in the skies ?

Yes we did, just a couple if I remember correctly and relatively minor failures at that. (Regular ultrasonic NDT inspections had been instigated to pre-empt these failures from actually occuring). New elevon purchases were rightly seen to be the answer to the problem; the poorly designed trailing edge extension modifications of the late 1970's were as was said before, the source of these failures, due to moisture ingress in the honeycombe structure).

Mr Vortex

I've just wonder that does the Concorde use a surge tank or
some a kind of a NACA duct like on B737 for pressurize the fuel in a tank?

As has been posted previously, there was a small NACA duct on the right hand side of the fin, that provided the air source for fuel tank pressurisation. This pressure was controlled to 1.5 PSIG.

Also, in Concorde F/E panel around the fuel control panel there're switch call trim pipe drain switch. Which I tried to read and figure it out but finally I don't know what it actually do and in which circumstance do we need to use it

This switch operated two valves that would drain out any residual fuel for maintenance (for example, replacing a vent valve); it was not used very often however.

Islander539 and ChristiaanJ
The actions of Airbus at Filton are nothing short of disgusting. By 'removing the insulation' you will need to strip the cabin completely bare (seats, galleys, ceiling panels and all of the side-wall panels). They say that 'Filton was only ever going to be an interim home for Concorde', what total crap!!
The idea is to 'cocoon' the aircraft 'until a permanent home is found'. I hope all readers here realise that this will involve BREAKING UP THE AIRFRAME to make it road transportable. The reasons that scarebus are giving for all this are vague and misleading, but here's my take. There are pressures around from various people and bodies 'to return a British Concorde to flying condition.' Now a lot (NOT ALL) of these people although very well intentioned are not that well informed and their wishes are not reasonably possible. But the pressures exist nonetheless, and scarebus will do anything to prevent this possibility, nomatter how unlikely, from being progressed. So we have G-BOAF, the youngest Concorde in the world, with the lowest airframe hours, in pretty good structural condition (she's suffered from being outside for 7 years, but nothing terminal) and actually in the hands of the dreaded scarebus (who would rather forget that Concorde ever existed, and was almost certainly the reason why they even noe exist). Doesn't take much working out now, does it?

Dude

[M2dude]

EXWOK

Or was it 18?? Late at night here - I'll think about it tomorrow!

I think you will find it was 18° TLA mate (age catching up with us??? . OK I know it has been 7 years).
The 18° TLA limitation was set to prevent TOD 'pop' surges, due to the resulting large intake ramp angle causing excessive compressor face distortion (the one side effect of the intake 'thin lip' modification).

Best Regards
Dude

[EXWOK]

Thanks Dude. Age and time catching up, but probably mostly caused by having been awake for 24hrs when I posted!

Seemed a good idea at the time.

I echo your fears about AF - it would be nice to see some of the enthusiasts with wild ideas scale them down a bit and focus on saving AF rather than an impossible pipedream.

Has AF really accrued fewer hours than AG, with her time out of service?

Always my fave so I'm particularly keen she doesn't get butchered.

[M2dude]

EXWOK

Has AF really accrued fewer hours than AG, with her time out of service?

arghhhhhh.. age is catching up me ME
You are quite correct, Alpha Gulf accrued 2000 less airframe hours than Alpha Fox, mainly due to her protracted 'holiday' between 1982 and 1985.
Totally agree with you about not letting the scarebus b****s buther OAF. OAA became a truly pitiful sight when they chopped the wings off for transportation. (You can still see the massive 'cut lines' on the wings, the effect of this effectively in my view 'killing' the aeroplane).
It's all a little personal for me too; I did my very first LHR-JFK in OAF in September 1982, returning the following day in OAA. (Hutch, Chris Norris and Chopper Bill were the operating crew..... This old fart can still remember something I guess).

Regards
Dude

[CBLong]

Orbital effect?

Hi M2dude, or anyone,

This very interesting thread reminded me of something I pondered many years ago... it occurred to me that Concorde, or any fast aircraft for that matter, must experience an apparent reduction in weight due to its speed. In other words, if Concorde went even higher and faster, it would eventually become weightless and could remain in orbit, but even at 60,000 feet and Mach 2, it would experience some reduction in weight, due to (for want of a better term) the centrifugal effect of travelling very fast in a circle, following the Earth's curvature.

Do you know, was this effect considered significant enough to come into the designed performance calculations? I think the effect was in the order of a 2% reduction in weight, if my back-of-envelope calcs were anywhere near correct.

Cheers,

Chris.

[EXWOK]

2% seems a bit high to me - but I haven't tried to calculate it yet.

Coriolis effect was measurable if you looked for it - about 1 degree of bank, I recall.

I believe the control laws of the FBW Airbii have to take it into account, as they command 1g in level flight. I'm sure there are people out there who know.....

[ChristiaanJ]

Just some notes on the side.

Originally Posted by M2dude

...By 'removing the insulation' you will need to strip the cabin completely bare (seats, galleys, ceiling panels and all of the side-wall panels).

With the lack of comm from Airbus, of course we don't know the details, but I would have thought the problem is essentially the under-floor insulation, the same that causes the musty smell in the Fox-Charlie cockpit. If so, I doubt they'd bother to strip the cabin.

They say that 'Filton was only ever going to be an interim home for Concorde'.

This is nothing new.
For "Filton", read "Filton airfield and the Airbus site".

The idea is to 'cocoon' the aircraft 'until a permanent home is found'. I hope all readers here realise that this will involve BREAKING UP THE AIRFRAME to make it road transportable.

At present, the 'permanent home' is planned to be at Cribb's Causeway, where land is already available.
Since this is only just on the other side of Filton airfield, so far there is no question of breaking up the airframe, or road transport.

The reasons....here's my take. There are pressures around from various people and bodies 'to return a British Concorde to flying condition.' Now a lot (NOT ALL) of these people although very well intentioned are not that well informed and their wishes are not reasonably possible. But the pressures exist nonetheless, and scarebus will do anything to prevent this possibility, no matter how unlikely, from being progressed.

I doubt this.... The "pressures" from these bodies and people consist only of noises on internet forums and in the press. As long as BA (as the owner), Airbus (as the current 'guardian' and legacy manufacturer) and the CAA (as the regulatory body) say "NO", Airbus knows perfectly well it'll never happen, pressures or no pressures.

My own take is simply, that they're fed up with a Concorde on their site, that their early 'enthusiasts' who campaigned for 'A Concorde at Filton' have now left, and that it's now Airbus exerting pressure on the Concorde Trust and other bodies to provide that 'permanent home' they've been talking about for years.

G-BOAF, the youngest Concorde in the world, with the lowest airframe hours, in pretty good structural condition...

To be exact, 18,257 hours and 5,639 supersonic cycles
As noted in another post, not the lowest, but a lot less than the 23,000+ hours of G-BOAD and G-BOAE.

In 2003, the issue with G-BOAF was that she was almost 'out of hours', with only a few hours left until the next big overhaul (an 'Inter', IIRC).
At the time, this was the reason why G-BOAF did not partake to the full extent in the flying during the last months, so as to have a few hours 'spare' for the last few flights, and of course the final flight.

Nowadays of course this is pretty irrelevant since any aircraft after seven years outside would need a 'Major' overhaul at the very least .
And that's another reason why Airbus wouldn't be bothered by those "pressures" mentioned earlier... they know perfectly well nobody is going to come up with the £100M +++ to re-create the necessary infrastructure.

CJ

[ChristiaanJ]

Originally Posted by CBLong

Concorde, or any fast aircraft for that matter, must experience an apparent reduction in weight due to its speed. I think the effect was in the order of a 2% reduction in weight, if my back-of-envelope calcs were anywhere near correct.

Well, here are my back-of-envelope calcs, with approximate figures, so everyone can check. (After all this IS Tech Log.)

'Centrifugal acceleration' = v² / r
Speed of sound 300 m/sec, aircraft speed Mach 2 = 600 m/sec, v² = 360 000
Earth radius 6000 km = 6 000 000 m
Accel 360 000 / 6 000 000 m/sec² = 0.06 m/sec²
Gravity: 1 g = 10 m/sec²
So the weight loss is 0.06/10 = 0.006 = 0.6 %
So a Concorde 'en route' at 300 000 lbs would actually weigh 1800 lbs less due to this effect.

But there's another effect.....
You're flying at 18 000 m (60 000 ft), so you're 18 km further from the centre of the earth than on the ground, and gravity decreases as the square of the distance.
Again with approximate figures:
You're 6018/6000 = 1.003 further away. Ratio squared = 1.006 (or rather 1/1.006=0.994).
And there goes another 0.6 %!

Since the two effects are not related, that's 1.2 % 'weight loss'.

Obviously, the INS (inertial navigation system) 'knew' all of this... it even knew the earth isn't round.

But it might be interesting to know where else this came into play.
One example : in theory the aircraft did weigh 1.2 % less, so the lift was 1.2 % less and the drag was 1.2 % less, so the fuel consumption was less too, so did Concorde have another 50-odd miles range thrown in 'free' by flying higher and faster than it's low-down subsonic brethren?

Even a passenger weighing 165 lbs would already have lost 2 lbs, just by flying on Concorde.
But of course, that's where Landlady comes in... "champagne, caviar, anyone?"

CJ

[Nick Thomas]

I have yet another question!

This one concerns the FE and his Sharp pocket computer. On the ITVV DVD the FE explains that he takes a set of engine readings and then enters them into the pocket computer to arrive at an engine trend which he then plots onto a graph. I noticed that the graph was titled "EGT trend".

As there are EGT gauges on the front panel, I was wondering why readings taken directly from the gauges were not used or does the computer average out the EGT for the four engines? Are the EGT readings taken over a standard period of time or for different phases of flight etc?

Looking at the readings it appeared that he had recorded a lot more readings than just the EGT. He also added that the readings were handed to the ground engineers at the end of each flight.

It would be interesting to know what readings were recorded and the significance of them to the ground engineers. Also could the FE deduce anything form the EGT trend graph?

Regards
Nick

[M2dude]

ChristiaanJ

With the lack of comm from Airbus, of course we don't know the details, but I would have thought the problem is essentially the under-floor insulation, the same that causes the musty smell in the Fox-Charlie cockpit. If so, I doubt they'd bother to strip the cabin.

With respect my friend that is utter codswallop. You can doubt things all you want, they've already said that they would remove it all; that by definition means all the cabin side-walls, galleys and roof panels, as well as the underfloor areas. When G-BBDG (202) was cocooned at Filton they did just that, and the only intact part of the interior left was the flight deck!!

At present, the 'permanent home' is planned to be at Cribb's Causeway, where land is already available. Since this is only just on the other side of Filton airfield, so far there is no question of breaking up the airframe, or road transport.

Unfortunately, this lot have a habit of talking with forked tongue as far as Concorde goes; you can not in any way be sure about this, and we should really stop believing everything that this lot in Toulouse tell us. (Recent history here has taught us this all too well, and nothing would please scarebus more than there to be no reminders of Concorde at all on the airfield at Filton). More to the point, there is absolutely no certainty that the Cribb's Causeway site will ever be built anyway, you just can NOT say that the airframe will not ne broken up for road transportation, because if she does go to another museum in the absence of the Cribb's Causeway site being built, that will DEFINATELY happen. But at least we now have another 'written off' British Concorde; I guess this fact obviously pleases some people

I doubt this.... The "pressures" from these bodies and people consist only of noises on internet forums and in the press. As long as BA (as the owner), Airbus (as the current 'guardian' and legacy manufacturer) and the CAA (as the regulatory body) say "NO", Airbus knows perfectly well it'll never happen, pressures or no pressures. My own take is simply, that they're fed up with a Concorde on their site, that their early 'enthusiasts' who campaigned for 'A Concorde at Filton' have now left, and that it's now Airbus exerting pressure on the Concorde Trust and other bodies to provide that 'permanent home' they've been talking about for years.

Total crap I'm afraid Christian. You can doubt it all you want; you're entitled to your opinions as we all are here. But the fact remains that there is a certain producer of airframes in Europe that has come out with nothing but lies and deceit with regard to Concorde, since early 2003, and it continues to do so to this day. (Guesses anyone?) You conveniently seem to forget that it was scarebus themselves who unilaterally closed the Concorde Filton exhibit...'for maintenace' .. YET ANOTHER TOTAL PACK OF LIES!!
And as far as responding to pressures; They could not give a flyingabout Concorde pressures, they JUST DO NOT WANT TO KNOW!! And yes they are fed up with Concorde.. poor dears. Perhaps OAF should never have gone to Filton in the first place; The continuing thought of Filton bending over backwards to please it's French masters makes one want to throw up. The basic fact remains that any British Concorde anywhere NEAR an Airbus plant is nothing more than an embarassment to them, and is fundimantally always in jeapordy.

In 2003, the issue with G-BOAF was that she was almost 'out of hours', with only a few hours left until the next big overhaul (an 'Inter', IIRC). At the time, this was the reason why G-BOAF did not partake to the full extent in the flying during the last months, so as to have a few hours 'spare' for the last few flights, and of course the final flight.

Big deal, she needed a C Check. Unlike in France, a Concorde major (D check) here did not take over a year to complete, and an inter could be in and out of the shed in a couple of months. Oh, and the check was completed correctly and thoroughly.

And that's another reason why Airbus wouldn't be bothered by those "pressures" mentioned earlier... they know perfectly well nobody is going to come up with the £100M +++ to re-create the necessary infrastructure.

I tend to agree with the RTF point, the £££££'s involved are generally prohibitive and it will probably never happen, but you and I have been in aviation long enough to realise that nothing is impossible. (At least not this side of the Channel). All aircraft left outside in the elements are obviously going to suffer, and it is irony of ironies that the FRENCH aircraft are generally stored indoors in the dry and warm, where the British were ALL intitially stored outside, exposed to the elements. (Only OAC in Manchester and OAE in BGI are now finally cared for under cover, the poor old 'wing clipped' OAA in Edinburgh does not really count). This ridiculous fact is is a source of both wonder and ANGER in the minds of most Concorde people in the UK. (Makes me sick personally!!).

Dude

[M2dude]

Nick Thomas

Looking at the readings it appeared that he had recorded a lot more readings than just the EGT. He also added that the readings were handed to the ground engineers at the end of each flight.
It would be interesting to know what readings were recorded and the significance of them to the ground engineers. Also could the FE deduce anything form the EGT trend graph?

Oh the Rolls Royce EGT Trend Monitoring Programwas an incredible piece of kit indeed Nick. The idea was that you would input Mach, TAT, N1, N2 and EGT itself. The computer program written in BASIC (I still have a copy) would then calculate the 'brochure' EGT for those conditions (the brochure itself being based on a 127° ISA +5 day), and what the delta from this brochure figure actually was. This delta EGT trend over the last few flights was then plotted (it was the delta rather than the actual brochure itself that we were interested in) and if there was a sudden jump or dip from the previous flights, it was indicative of something wrong with the engine. A severe dip was indicative of compressor damage and a severe jump indicative of turbine damage. Boroscope inspections would be carried out in such a case, and the Trend Program was better than 90% accurate in terms of predicting engine problems, although these problems became less and less common as the engine design became more mature. (As a result of modifications embodied in the engine over the years). FOD damage ended up being the most common cause of headaches here.
The obvious remedy for confirmed compressor or turbine damage was to 'pull' the engine and replace it with a 'new' one; the damaged engine was then sent to Treforest in Pontypridd for overhaul. (These guys by the way did a really superb job ).

Best Regards
Dude

[Lord Bracken]

I would be grateful if any of the fantastically knowledgable posters on here could provide more details of the formation flying that went on on December 24, 1985.

YouTube - Concorde formation (from the cockpit)
YouTube - CONCORDE FORMATION (eventual publicity video)

Seems like a wonderful experience.

Another vote from me for best PPruNe thread ever - thank you all very much for taking the time to produce such fascinating reading.

[Nick Thomas]

Thanks Dude for your clear answer.

Now am not sure if the following has been discussed earlier on this thread, so please accept my apologies if it has.

Dude in your answer you mentioned putting an overhauled engine onto the wing. Therefore how many engines were available to BA? I guess production of the engines stopped many years ago. Am I correct to assume that? and if so when was the last engine produced? How long normally would an engine be on Concorde before it would need servicing? Would it have been possible to keep on overhauling the engines? and if not would the lack of engines have resulted in the grounding of Concorde before grounding due to air frame considerations?
Regards
Nick

[M2dude]

Nick I can't quite remember the numbers, (I must find out) but we always had a sufficient float of spare engines to cope with out needs. Engine changes in the early days of operation were quite common, with average on wing live being little more than 600 hours. Eventually, through modifications the on wing life more than quadrupled, but still only a fraction of the time that a big fan engine would stay on wing. (The Olympus 593 was subject to so much more thermal and mechanical stress than a subsonic engine during cruise flight). Although the last engines were built at Patchway (Bristol) sometime in the 1980's (IIRC) there was virtually no limit to the number of times that an engine could be overhauled, as new turbine and compressor blades, combusion chamber components etc. were always being manufactured during airline service. Apart from pulling engines due to EGT Trend induced boroscope inspections, another reason was as the result of an engine oil sample chemical analysis, where the presence of certain contaminant metals would indicate such things as potential gearbox failures.
But in order to fully answer your question Nick, we could have carried on operating Concorde almost indeffinately, as far as engines went.

Best Regards
Dude

[M2dude]

Lord Bracken

I would be grateful if any of the fantastically knowledgable posters on here could provide more details of the formation flying that went on on December 24, 1985.

This wonderful event was to to celebrate the 10th anniversery of Concorde passenger services by way of a four ship photo/video shoot. The twp pilots involved on the first video, Capt's Dave Leney and John Hutchinson were two of the nicest gentlemen that I have ever had the pleasure of knowing.
The co-ordination of the event required a great deal of co-operation from Air Traffic Control and was an incredible spectacle.
Best Regards
Dude

[ChristiaanJ]

M2dude,
I remember reading a fairly detailed account of the day somewhere, either in a book or on the internet. Would you know where?

One snippet was that during the four-in-line formation, the line-up was less than perfect, and that afterwards there was a lot of good-natured ribbing among the pilots, whether n° 2 should have slowed down just a tad, or whether it were n° 3 and 4 who couldn't quite catch up....

IIRC, it was the same specially outfitted Lear Jet that filmed the formation, that also was used to take some of the other well-known Concorde air-to-air shots, and that was used for the filming of "Airport 79 - Concorde".

CJ

[CAAAD]

Dude - I think basic engine hardware was in good supply, but there were concerns about the control amplifier component availability.

We have a couple of Olympus intake blanks which we find absolutely perfect for gardening with our aged knees.

[ChristiaanJ]

Originally Posted by CAAAD

Dude - I think basic engine hardware was in good supply.... We have a couple of Olympus intake blanks which we find absolutely perfect for gardening with our aged knees.

Yes, I can imagine they would be perfect for that!
Not to mention the vast quantity of spare compressor and turbine blades and stator vanes, spread far and wide after the end-of-service, through the spare parts auctions.



(The model is a design that was part of my engineering studies - late '60s - but the compressor vane is real Concorde.)

....but there were concerns about the control amplifier component availability.

Tell us more?
M2dude and myself already have mentioned the same problem with the AICU (air intake control computer) in this thread.
People do only rarely realise how rapidly technology was changing in the early Concorde days, and how difficult it was to procure components that sometimes were already obsolete when Concorde entered service.

CJ

[M2dude]

ChristiaanJ
There is THIS link from Gordon Roxborough's superb 'ConncordeSST site' CONCORDE SST : 10th Anniversary
As you can see the event occured on Christmas Eve in 1985. As you can see from the video, Capt John Hutchinson was also aboard G-BOAG as a commentator, the F/O being John 'Noj' White. (After leaving the fleet when he got his command, Noj eventually returned to Concorde many years later as Capt Noj).
At the bottom of the web page I am 99% sure that Gordon got it wrong when he said that the reason that there were only 6 aircraft for the Boxing day 'group photo' was that the seventh aircraft was in the paint shop. I was there when we did the photo shoot, and I am pretty sure the only reason we never had aircraft 7 was that it was in JFK.

CAAAD

Dude - I think basic engine hardware was in good supply, but there were concerns about the control amplifier component availability.

I wouldn't be at all surprised (the Ultra ECA was a real steam powered piece of kit) but we always managed to get obsolete/obsolescent electron component somewhow. I remember when we test flew the Plessey (I think) digital ECA on G-BBDG in the late 1970's it was a fraction of the size, ran cooler and the engine parameters were more stable too. Such a pity that we never went down that road for the production aircraft.

Regards
Dude

[speedbirdconcorde]

Discussing the formation video...and video in general, I would assume there is one hell of a lot of footage out there that we have never seen ( at least I hope so ! )....we see snippets here and there but I wonder what happened to most of it ? Would be depressing to think some of it ended up in old tins and junked somewhere. Really referring to the days of construction and testing - would love to see video of the engine testing, flight testing, fuel rig, and the folk involved. Even more footage of the formation video or some of that spectacular footage we see of Concorde behind the 'chase plane' in flight...amazing stuff. Is most of it in the hands of BA or .... ?

Cheers.