ChristiaanJ - Upon reflection, I'm not sure that it was the Relight Envelope, but the shape is similar to an engine performance relationship where the 'horse's neck' was referred to.

But the Relight Envelope was established by demonstrating relights during flight testing, on the basis of a theoretical envelope.

There would have been much discussion on the build standard and state of deterioration of engines involved and so on.

Sorry I haven't a copy of the Envelope, but I'm sure it will be in the Flight Manual.

Vmo reduction below 5000ft
 

I was always under the impression this was the equivalent of the 'bird speed' limitation some older Boeings carry.

We would definitiely have performed better if we could have got to 400kts at, say 3000'.

Interestingly, this was a fairly blunt instrumenet insofar as it was based on pressure altitude, so departing from Nairobi (where there's a good chance of meeting sizable birds) one would find the barber's pole already at 400kts or so.

CAAAD

From the Cruise Control Manual:

http://i303.photobucket.com/albums/n...scan0005-1.jpg

Best Regards

Bellerophon

Well as that well known lady Randy Mice-Davies said " They would say that wouldn't they" (That shows my age!)

Seriously, they couldn't possibly know that the new nozzle fell short of it's design promise. There was no means of measuring thrust in flight installed on the aircraft and even if there had been the possible precision would not have allowed one to make such judgement. The only certain thing in aircraft design is weight, and that could be established unequivocably - it was lighter than the original. Any aerodynamicist looking at the two designs could tell you that the drag of the TRA (Tuyere Reverse Aval) was going to be less than that of the prototype nozzle, but establishing an exact value was another matter.

For the record. the idea of a new design originated in Sud Aviation. The development of the design was entrusted to a joint BAC/RR/Sud/Snecma team (I was one of that team, so maybe I am biased!). Snecma were not very keen on the idea of a new nozzle, largely from pride and a strong NIH factor, but one could not in fairness blame them for any performance shortfall - it was a joint effort.

CliveL

A pot pourri of responses after my Christmas reading!

This actuallyis interesting in that the numbers show one of the fundamental features that made the Ol 593 such a good choice. If you look closely at the TO and cruise values you will find that at TO the overall compressor pressure ratio is 13.5 the compressor exit temperature 460 degC and the turbine inlet temperaure is 1152 degC. In cruise the pressure ratio is 10.5, the compressor exit is 565 degC and the TET 1100 degC.

Somebody, I can't find the exact post, was asking whether the elevated cruise total temperatures affected engine life, and here we see why this is so. As Christian said in another posting, when you compress air it gets hotter - from 21 degC to 460 degC at take off and from 127 degC to 565 degC in cruise. A fundamental limit on engine operation is the turbine entry temperature. Not only does it affect the maximum TO thrust you can get but also the continued exposure to cruise TETs has a very big effect on engine fatigue life, and engine manufacturers have shown extremes of ingenuity when developing new materials and ways of cooling the blades to increase allowable TET.

The problem with supersonic operations is that you start from an elevated intake delivery temperature so that when the flow exits the compressor it is already very hot 565 instead of 460 to be exact. But the maximum temperature one can stand for fatigue reasons is limited, therefore the amount of fuel you can pour in must be limited also, and the thrust you can develop per pound of airflow is roughly proportional to the fuel input/temperature rise. To get any sensible cruise thrust then one must squeeze the cruise TET as high as you dare for fatigue reasons but also you need to keep the compression ratio down so that the temperature going into the combustion chambers is as low as you can get away with. This tend to drive engines designed for extended supersonic operations to having a low pressure ratio. This is against the trend in subsonic operations where compression ratios have been steadily increasing along with bypass ratios.


The net result then is that the engine must be designed with a low OPR and must operate with cruise TET much closer to its TO TET value than would be necessary, or indeed desirable, on a subsonic design.



Actually, here, as on some other apparent carry-overs, one should look at the equipment supplier rather than the aircraft manufacturer to trace continuity. Here we have Messier supplying Concorde's gear and Dowty (OK they are now part of Messier) supplying the A330. And having worked on both, I seem to remember that the means of doing the shortening are quite different.

Quote:

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Originally Posted by Brit312

The Britannia and now you are talking about the love of my life and yes I do remember the story of the nose and visor selector, but we have forgotten the most obvious. Where do you think they got the idea for the control column from

---

Yes, they both came out of the Bristol drawing office. One minor anecdote: the 'ramshorn' stick was a novelty to the Concorde flight test crews but they got to like it, or at least put up with it. All went well until it came to the time when Dave Davies, the ARB Chief Test Pilot, came to put his rubber stamp on the aircraft.

Concorde's seats, just like those on your car, could be moved back and fore to get your legs on the pedals and up and down so you could see over the bonnet (sorry, instrument panel). The control column of course stayed in one place, so the relationship of the 'horns' to ones thighs varied with ones height. Andre Turcat was about 6ft 2in, Trubbie and the others of average height. The smallest regular pilot was Jean Franchi at, I suppose, about 5ft 7 or 5ft 8. No problems. But Dave Davies was short like me and he found that he could not get full back stick and full aileron because the ramshorn fouled his thighs.


Consternation! Completely unacceptable! I don't know what arguments they used to convince him it was all OK really, but it got through certification. I would certainly be interested to learn from the pilots in this group as to whether it was ever a problem.

Quote:

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Originally Posted by exWok

........which was one reason it was so important to touch down with the wings level - even a very small angle of bank could result in bucket contact as they translated to the reverse position. It was a surprise coming to Concorde to find it was even more restrictive than the 747 in this respect

---

I can't resist this one!. Has anyone ever noticed/wondered about the tiny bit of the outer elevon that has been chopped off? That was my first real input into the design as a young erk looking at variability of touchdown conditions and coming to the conclusion that if the pilot got into trouble and was trying to pick up a trailing wing with too much AoA as well then he was likely to hit the ground with the downgoing elevon. I persuaded my boss that this was so and we made a small adjustment.
In self defence I am going to plead that this was well before the days of the Type 28 nozzle, so the issue of buckets contacting the ground first never came up!

Quote:

---

As far as your point about the prototype engines; they were way down on thrust anyway, (even without the 'help' of the silencers), produced more black smoke than a 1930's coal fired power station.

---

To the point where an American Airline maintainance engineer, watching a prototype taking off and with full benefit of being located strategically for maximum sideline noise, remarked on what he described as 'visible acoustic radiation'

On another occasion, it was reputed that Stanley Hooker, watching a TO in the company of HRH the Duke of Edinburgh, remarked that "You know Sir that that noise represents less energy than it takes to boil an egg". to which he got the reply "Then I must congratulate you Sir Stanley, on producing so much noise for the expenditure of so little energy".

Quote:

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Originally Posted by CJ

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?

---

There was an effect and in consequence the aircraft performance brochures were formally calculated for north/south flight. Pity really, it would sometimes have been nice to be able to fly guarantee performance demonstrations in the most favourable directionhttp://images.ibsrv.net/ibsrv/res/sr...ies/shiner.gif

That's enough for today!

CliveL

Spot on, Clive.

I've said something similar (while at the same time being full of admiration and effusive praise for M2Dude). It's worth bearing in mind that at the time (2003 or thereabouts), AI were fighting a battle to keep the A380 project viable (like Boeing with the 747, they'd effectively "bet the company" on the project's success) - and sadly, in terms of business realpolitik Concorde was costing them money, being just a small-run legacy airframe capable of operating profitably for a single customer. Things weren't going to get any better, and as such AI's decision was as understandable as it was regrettable.

I have far less sympathy for BA, who acted with what seemed to me indecent haste to permanently mothball the airframes (the press at the time speculating that Branson would try to get his hands on at least one of them), and while the UK Concorde community have a right to feel aggrieved at the way things panned out - the fact that what was left of BAe effectively bowed out of the Airbus consortium, the better to focus on military hardware with the Americans, meant that we'd thrown away any chance of having a say in what happened to Concorde in the end.

EDITED TO ADD : In reference to Bellerophon's post below - this was *not* intended to take the technical discussion off-course. I was simply trying to thank Clive for summing up how I felt about the whole situation far better than I ever could. Sincere apologies if this was misconstrued as such.

May I echo a plea that ChristiaanJ has already posted on this thread, and respectfully suggest that we try and keep this thread free from opinions and debate about the Gonesse accident and the subsequent withdrawal of Concorde from commercial service?

Most contributors to this thread will doubtless have strongly held opinions and views on both these topics. Some have posted comments here, but whilst I respect their views and their knowledge, are not these topics already more than adequately catered for on other threads and forums? Frankly, I have to confess that I have grown weary with most such threads, and, in general, neither read them nor contribute to them.

I do, however, greatly value having just one Concorde thread devoted purely to technical comments, anecdotes and personal reminiscences. Perhaps, if others feel similarly, we might try and keep this thread that way?

Happy New Year

Bellerophon

Number of Wheel Brakes
 

Question 8: Nine (includes one for the nose axle, used only during gear retraction.)

Sorry Bellerophon, I most definitely did NOT want to reopen any debate, but I felt that the previous remarks left unsaid things that should have been said. I fully agree that the value of the thread lies in the technical discussions.

I will now SHUT UP on the subject

CliveL

Peak fuel consumption - question
 

I have been a Concorde fan since I won a flight on it in 1980, courtesy of a competition in the Birmingham Evening Mail.

I got the Haynes Manual for Christmas. On page 95 there is a diagram and photo of the centre dash panel, showing among other things the fuel consumption gauges, which, remarkably, read up to 35 tonnes per engine per hour. There appears to be two digital displays per gauge as well as an analogue display.

What was the peak consumption per engine, and why two digital displays on each gauge?

To refresh memories, here's the only, not very helpful, entry in the Flying Manual that I've found.

http://img.photobucket.com/albums/v3...24fuelflow.gif

My guess is that the upper digital counter indicates the proportion of the fuel flow that goes to the reheat but it's only a guess.

Sorry, I have no figure for the max fuel consumption.
The '35 tonnes/hr' limit on the indicator is obviously beyond the upper limit, like the speedo on a car.....
But yes, fuel consumption at takeoff with reheat was horrendous, and would have emptied all the tanks in an hour or less.

CJ

Any chance of you telling the tale?

We're looking forward to a few more people like you telling their story.

Peronally, I still remember vaguely there's a tale of the customers of a country pub somewhere in England actually chartering a Concorde for a "round-the-bay" flight, but I've never been able to find the full story.

CJ

Thankyou to everyone on this thread for without a doubt the best thread i've ever read on any internet forum - the passion and knowledge floors me. I have zero aviation background but Concorde has a place in my heart....I was wondering however if someone on here knows about the following story? To this date i've no idea what bits are the truth and what is just rumout.

My grandad (departed earth long before I was old enough to ask him questions about it unfortunately) worked for a company (don't believe they were a specific aerospace firm just a precision engineering firm, he also worked on flaps/droops on Tridents and said he had many a sleepless night when G-ARPI initially crashed). They won the contract to make the keys for Concorde, my grandad makes the keys according to the designs, and for extra measure thinking they will be a souvenir no doubt one day decides he will make a set for himself (and who knows, I could've ended up with them). So the story goes the dies then get destroyed.

Launch day of Concorde comes, BA lose the set of original keys made and only asked ever for one set - the launch looks in jeopardy and a somewhat panicked launch party are wondering what they are going to do. Luckily my grandad steps up and says you have been saved, as he had a spare set all along and gives them to BA who launch as planned but loses out his souvenir in the long run.

As I say to date I have no idea if its the truth or not and it could be alot of artistic licence across the years (I can't believe they made just the one set, but don't know whether they were common keys or specific to the aircraft or what), but thought if anyone would know its someone on here and give me something to tell my grandkids if its true!

Thankyou, and long may this thread continue.

"round-the-bay"
 

During my regrettably short tenure working with "The Machine" these charters were known by one or two folk as "Bangs around the Bay"...

anyhow.. back to CJ's question, They may not be alone, but the splendid Bell at Aldworth did a pub charter in '78... Heritage Pubs, National Inventory
(see last paragraph)

And yes, wholeheartedly agree with PNC and others keep this up!

GB

My Concorde Trip
 

As prompted by ChristiaanJ. I won the trip in a competition using Prestel (anyone remember that?). I was using my employer's Prestel set and had to lie about it else the prize would have been raffled among my colleagues;).

It was a 1 hour and 40 minute flight from Manchester to Paris, via Ireland and the Atlantic Ocean, accelerating to Mach 2.0 and immediately slowing down again. It was a charter flight in which the other 99 seats were occupied by the most successful fire extinguisher salesmen from a company called Chubb. Return was the following day, on a BAC 111. I spent a beautiful September evening in Paris, and it cost me a fortune. Having arrived by Concorde I tried to live up to the image, seeing a show in the Lido, buying a meal on the Champs Elysee, and buying souvenirs for the wife and children. I later discovered that all the fire extinguisher salesmen had spent the night in the hotel bar:sad:.

What I remember about the flight was the phenomenal acceleration on take-off, at a light weight, the spectacular climb rate, and the fact the window got perceptibly warm when supersonic. Also, as I was sitting near the back I could see the floor of the aircraft flexing slightly, a bit like a fishing rod. We only went to 43,000 feet so the sky did not get very dark.

A bit of politics here: I always thought that Concorde was Britain's admission ticket to the European Union. And national pride - nothing wrong with that!

911slf

...I have been a Concorde fan since I won a flight on it in 1980...

Lucky devil! I'm glad you enjoyed the flight.


...There appears to be two digital displays per gauge as well as an analogue display...

http://i303.photobucket.com/albums/n...s/P4290024.jpg

Only the lower digital counter was actually a display, and was a digital repeater of the total fuel flow information being displayed by the pointer on the dial. The upper digital counter was merely a digital indication of the value to which the internal yellow triangular bug had been set by the F/E using the bug setting knob on the lower right of the gauge.

Very briefly, during the pre-flight set up, the F/E would calculated the expected fuel flows for each engine, during the take-off whilst using re-heats. He would set this on the bug, and this achieved two things.

Firstly, it gave him a good visual indication whether the required fuel flows were being achieved. Too low a fuel flow would indicate a re-heat problem on that engine.

Secondly, it programmed the expected fuel flow into the engine take-off monitor, as this was one of the parameters that had to be satisfied in order for the monitor to illuminate the Green “Clear-to-Go” light.

The Green “Clear-to-Go” light was one of three “Power Management” lights immediately above the N2 gauge for each engine, the other two being an Amber “Configuration” light and a Blue “Reverse” light. Some take-offs would require all four Green lights to be on, other take-offs, depending on ambient conditions, aircraft weight and runway length, might only require three Green lights.


...What was the peak consumption per engine, and why two digital displays on each gauge?...

The maximum peak consumption predicted was 21,700 kg/eng/hr, or 86,800 kg/hr total. This would have been predicted for a re-heated take-off, at +8°C, at an elevation of -1,000 PA.

More typically, on a standard day, at a sea level airfield, 20,700 kg/eng/hr, or 82,800 kg/hr total. You can probably see why we turned the re-heats off fairly quickly!


...accelerating to Mach 2.0 and immediately slowing down again....we only went to 43,000 feet so the sky did not get very dark...

43,000 ft is actually a bit too low for Concorde to be at M2.0, as you may see from this graph of her Flight Envelope. She would have been limited to around 525 kts / M1.7 at that height, so I suspect you may have been a little higher than you remember, possibly somewhere around 53,000 ft.


Happy New Year

Bellerophon

That's a very 'Concorde' picture, Bellerophon.

Gentle descent in the crz, N1 max, N2 max, similar fuel burn per engine as a 747 (but over double the speed), Airspeed and Mach numbers just shy of the barber's poles, must have been well above FL500 given the Mach number yet the cabin alt is a smidge over 5000'.

Elapsed time 1hr 31, Longitude over 41W. Took me over three hours to get to 40W yesterday.......

PS and it has to be OAD, because for some reason the nose/visor control panel is black. I've no idea why I can remember stuff like that, but not the name of someone I met last week......

Further PS ref. the fuel flow gauge - somone wondered if the target flow veeder counter was for reheat. We now know that it wasn't, but you will see a small 'Fe' annunciation in the 9 o' clock position indicating that the gauge is measuring engine flow only. When fuel is being supplied to the reheats this changed to 'Ft' with a white background to indicate that the gauge was displaying combined fuel flow. (Fe=engine, Ft=total)

thanks Bellerophon, and EXWOK for a comprehensive reply.:ok: