26th Dec 2010, 14:31
permalink Post: 1013
It could be felt on the flight deck, although the onset was not particularly noticeable, and tended to be masked by the fact that one generally lowered the visor and dropped the nose to 5 degs at about the same time.
27th Dec 2010, 14:04
permalink Post: 1026
A pot pourri of responses after my Christmas reading!
This actually is interesting in that the n umbers 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.
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.
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!
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".
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 direction
That's enough for today!
CliveL
Quote:
|
Originally Posted by
M2Dude
I hope this one is interesting; it's a Rolls Royce diagram illustrating what the wildly varying differences were in terms of the engine between take off and supersonic cruise. The primary nozzle can be seen at the rear of the engine, together with the reheat assembly and the secondary nozzle (reverser buckets).
|
This actually is interesting in that the n umbers 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.
Quote:
|
I
s this another item that Airbus used for the A330/340? I can't remember the exact arrangement for Concorde, but the 330 uses a clever lever arrangement at the top of the leg.
I was not even aware of this A33/340 similarity, sounds yet another case of Airbus using Concorde technology. (Immitation still is the greatest form of flattery I guess). As far as I am aware Concorde had none of the lubrication issues that you describe. M2Dude |
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:
|
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:
|
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:
|
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 direction
That's enough for today!
CliveL
3rd Jan 2011, 22:15
permalink Post: 1074
Quote:
|
Originally Posted by
DozyWannabe
Was there a reason - other than it was the second example built - that the French pre-production model had the longer tail assembly fitted, whereas 101 did not?
|
01 first flew in December 1971, 02 in January 1973, more than a year later.
So I suppose a lot of the planned improvements "came to fruition" just about then.
Apart from the new visor, 01 still looked a lot like another prototype, while 02 was externally almost indistinguishable from the production aircraft (long tail, new nozzles/thrust reversers, tail wheel, etc.).
However, from my own limited experience, as far as the cockpit layout, and systems like the AFCS, were concerned, 01 was already far closer to the production version than to the prototypes, which were still very much mid/late '60s designs.
The two prototypes were very much experimental and proof-of-concept aircraft, and it's interesting to see in how many aspects they differ from the final production aircraft.
CJ
15th Jan 2011, 10:59
permalink Post: 1100
A Journey Back In Time !!
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
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
Last edited by M2dude; 15th Jan 2011 at 11:29 .
28th Feb 2011, 23:20
permalink Post: 1221
Quote:
| 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. |
12th Mar 2011, 21:49
permalink Post: 1239
The engine starting sequence was also in airline operation 3-4-2-1. At the gate the altered sequence was 3-2 prior the pushback and 4-1 after due to safety reasons for ground crew and for noise restrictions at some airport stands.
Brit312 explained in post #140:
I must admit that I am no expert (not yet
), but it seems both sequences follow the logic to feed the blue hydraulic by engine#3 first, then one of the two yellow systems (2 or 4) and the green hydraulic (engines 1&2) which supplies power to some more services than the blue (droop nose and visor, landing gear, main wheel brakes with anti-skid and nosewheel steering).
Well, I hope, this was not a stupid answer before I took a chance for a nonstupid question
- but I am so exited about this thread and just want a little bit to give back!
Thanks for the probably best thing ever I have found in the internet. Thank you M2dude, Brit312, ChristiaanJ, Exwok, Bellerophon, Landlady et al.!
Brit312 explained in post #140:
Quote:
|
Yes we always started just the two inboard engines prior to push back and the outers when the push back was complete. This was for a number of reasons, but I do seem to remember it was not unheard of to break the tow bar shear pin on the initial push, so the less power the better
Remember that Concorde had no APU and no across the ship ducting for stating engines, therefore prior to push an air start unit was plugged into each pair of engines and the inboard engines would be started. This allowed, after push back, air from each inboard engine to be used to start it's outboard engine. The other good reason for starting the inboards prior to push was that with no APU the cabin temp would rise quite quickly [specially in places like Bahrain in summer] and never mind the passengers comfort, but some of M2dude and ChristiaanJ fancy electronic equipment was very temp sensitive , especially those intake control units down the rear galley. With Two engines running we could use their bleed air to at least try and hold the cabin air temp during the push back |
), but it seems both sequences follow the logic to feed the blue hydraulic by engine#3 first, then one of the two yellow systems (2 or 4) and the green hydraulic (engines 1&2) which supplies power to some more services than the blue (droop nose and visor, landing gear, main wheel brakes with anti-skid and nosewheel steering).
Well, I hope, this was not a stupid answer before I took a chance for a nonstupid question
- but I am so exited about this thread and just want a little bit to give back!
Thanks for the probably best thing ever I have found in the internet. Thank you M2dude, Brit312, ChristiaanJ, Exwok, Bellerophon, Landlady et al.!
11th Aug 2011, 13:32
permalink Post: 1423
Thank you
Dude
Many thanks for your comprehensive reply, you have indeed answered my curiosity and I couldn't for the life of me think of the words "circuit breakers" when I typed my message but you are right, thats what I meant in terms of the area behind the Captain and where the fourth cup holder is
.
I dont think this question has been asked so far and I always wonder, did they all fly the same or did the crews know that each airframe had her own foibles? I do understand that AA was a bit heavier than AG but were there examples of knowing that AC was a bit slow to get her nose and visor down for example?
Many, many thanks for your contributions and expertise I do so enjoy reading this thread, even with a heavy heart knowing shes no longer pushing Mach 2.00.
Regards
Sidders
Many thanks for your comprehensive reply, you have indeed answered my curiosity and I couldn't for the life of me think of the words "circuit breakers" when I typed my message but you are right, thats what I meant in terms of the area behind the Captain and where the fourth cup holder is
.
I dont think this question has been asked so far and I always wonder, did they all fly the same or did the crews know that each airframe had her own foibles? I do understand that AA was a bit heavier than AG but were there examples of knowing that AC was a bit slow to get her nose and visor down for example?
Many, many thanks for your contributions and expertise I do so enjoy reading this thread, even with a heavy heart knowing shes no longer pushing Mach 2.00.
Regards
Sidders
12th Aug 2011, 09:53
permalink Post: 1426
hissinsid
Really one for one of my pilot friends to answer, but there was the one issue where OAC had a heavier right hand wing than the left!! (Due to a major repair done in the early 1980's). And as you correctly point out, the last few aircraft built were indeed lighter than their earlier cousins.
speedbirdconcorde
Love the bit about the latte machine.
An updated flight deck would indeed look radically different than our 'classic' Concorde office
.
Perchance to dream
Personally I think this country needs to find a vision again, not just the money.
Reverserbucket
The hole you mention was a supersonic book stowage. Not very high tech I'm afraid.
Regards to all
Dude
Quote:
| I dont think this question has been asked so far and I always wonder, did they all fly the same or did the crews know that each airframe had her own foibles? I do understand that AA was a bit heavier than AG but were there examples of knowing that AC was a bit slow to get her nose and visor down for example? |
speedbirdconcorde
Love the bit about the latte machine.
An updated flight deck would indeed look radically different than our 'classic' Concorde office
.
Perchance to dream
Personally I think this country needs to find a vision again, not just the money.
Reverserbucket
The hole you mention was a supersonic book stowage. Not very high tech I'm afraid.
Regards to all
Dude
17th Nov 2011, 00:00
permalink Post: 1480
Quote:
|
Originally Posted by
Kiltrash
We cannot let this thread be consigned to the annals of forgotten history
There must still be a million questions that you always wanted to ask about this wonderfull plane |
Quote:
|
So here is mine
On Wikipedia they tell us there were 20 Concordes built, 14 production and 6 pre production |
There were two prototypes , 001 and 002 (the ones with the odd porthole visors).
There were two preproduction aircraft: 01, the British one, with a full 'look-through' visor' and 02, the French one, the first one that looked like the production model, with both a 'full' visor, and the 'pointy' tail.
Then there were two 'near-production' aircraft, that were used for certification, route-proving, and suchlike, but that never entered airline service (201 and 202, now best known as 'F-WTSB' and "Delta-Golf").
And yes, then there were 14 production aircraft, that in the end all made it into service with BA and AF.
Quote:
|
Also Wiki tell us there were 67 olympus 593 engines built
Forgive me but this does not seem possible, not enough engines were built to satisfy 'new' engines for 'new' planes on the production line. |
The '67' figure probably refers only to the version of the 593 engnes for the production aircraft (4x14=56, plus spares), and not to the earlier versions used for development/testing, for the prototypes, the preprods and the cerification aircraft.
Quote:
| Does this mean that the 6 pre production a/c donateded some engines to production aircraft so some BA and AF planes flew, even from new, with 'used' engines?? |
Funnily enough, there's a current discussion on a French Concorde forum on the same subject, trying to figure out not only exactly how many engines were built, but also the "where are they now?".
It would be a nice item to add to the "Concorde Story". We may have to appeal to the RR Historical Trust to open their archives, and tell us exactly how many Olympus 593's were built, and what they can tell us about their history.
CJ
17th Feb 2012, 12:55
permalink Post: 1568
Quote:
|
Someone's done the same sort of thing, albeit on a smaller scale, for the Bugatti Type 35. Is this the sort of thing you're contemplating?
1924 Bugatti Type 35 |
Quote:
| I think you might find you're conversing on this thread with some of the people who actually had a hand in creating the diagrams in the first place, etc. |
I think I'll try modeling the nose cone w/cutouts and the visor operations when I get some time next week. It's very simple, and a good place to begin animating the mechanics of lowering/raising the nose cone/visor.
18th Feb 2012, 12:59
permalink Post: 1569
Quote:
|
Originally Posted by
YearoftheTiger
I think I'll try modeling the nose cone w/cutouts and the visor operations when I get some time next week. It's very simple, and a good place to begin animating the mechanics of lowering/raising the nose cone/visor.
|
It's not Rube Goldberg, but it's still a pretty complex mechanism, with rails, hydraulic cylinders, uplocks (both hydraulic and manual), intermediate stops for the 5\xb0 and 12.5\xb0 positions, etc.
And you'll discover that (even on the production aircraft) the nose can still be lowered to 17.5\xb0 by removing a set of mechanical stops (IIRC the reason for that is already mentioned earlier in the thread).
Wishing you luck and courage with your venture, and I will be curious to see the final result!
CJ
8th May 2013, 16:05
permalink Post: 1714
For the french speaking (or reading) people here, I just found a mine of very interesting informations about Concorde on this website:
Accueil
This site has a database of thousand of concorde flights with the following datas: Date and time of the flight, airframe used, technical and commercial crews, guests, departure/arrival airports and flight type (regular, charter world tour...).
On top of that, many infos and stories around Concorde can also be found there.
I can't resist to translate one of those stories (I'm far from being a native english speaker or a professional translator; so forgive me for the misspellings and other translation mistakes). It is a report about one of the biggest incident that happened to the prototype 001 during the flight tests:
Shock of shockwaves
We were flying with Concorde at Mach 2 since 3 month already on both side of the Channel. The prototype 001 did outstrip 002 which was supposed to be the first to reach Mach 2.
Unfortunately, a technical issue delayed 002 and Brian Trubshaw fairly let Andr\xe9 Turcat be the first to reach Mach 2 with the 001 which was ready to go.
The flight tests were progressing fast and we were discovering a part of the atmosphere that military aircrafts hardly reached before. With Concorde, we were able to stay there for hours although limited by the huge fuel consumption of the prototypes.
The Olympus engines did not reached their nominal performance yet and, most of the time, we had to turn on the reheat in supersonic cruise to maintain Mach 2.
The reheat is what we call afterburner on military aircrafts. Fuel is injected between the last compressor stage of the low pressure turbine and the first exhaust nozzle. This increases the thrust for the whole engine and its nozzle.
The 4 reheats, one for each engine, are controlled by the piano switches behind the thrust leavers on the center pedestal between the two pilots. Air was fed into the engines through 4 air intakes, one for each engine, attached 2 by 2 to the 2 engine nacelle, one under each wing. The advantage in terms of drag reduction was obvious.
However, tests in wind tunnel showed that, at supersonic speed, if a problem happens on one engine, there was a great chance for the adjacent engine to be affected as well by the shockwave interference from one air intake to the other despite the presence the dividing wall between the two intakes. So we knew that an engine failure at mach 2 would result in the loss of 2 engines on the same side, resulting in a lateral movement leading to a strong sideslip that would likely impact the 2 remaining engines and transform the aircraft into the fastest glider in the world.
This is why an automatic anti sideslip device was developed and installed on the aircrafts.
The air intakes are very sophisticated. At mach 2, it creates a system of shockwaves that slows down the air from 600 m/sec in front of the aircraft to 200 m/sec in front of the engine while maintaining a very good thermodynamic performance. In supersonic cruise, the engines, operating at full capacity all the time, were sensitive to any perturbation and reacted violently with engine surge: the engine refusing the incoming air.
Stopping suddenly a flow of almost 200kg of air per second traveling at 600m/sec causes a few problems. As a result, a spill door was installed under the air intake and automatically opened in such event.
To control the system of shockwaves and obtain an efficiency of 0,96 in compression in the air intake, 2 articulated ramps, controlled by hydraulic jacks, are installed on the top of the air intakes in front of the engines. Each ramp is roughly the size of a big dining room table, and the 2 ramps, mechanically synchronized, move up or down following the instruction of an highly sophisticated computer that adapts the ramp position according to the mach number, the engine rating and other parameters such as skidding.
At that time, it was the less known part of the aircraft, almost only designed through calculation since no simulator, no wind tunnel, did allow a full scale test of the system.
The control of the system was analog and very complex but it was not easy to tune and we were moving ahead with a lot of caution in our test at mach 2.
On the 26th of January 1971, we were doing a nearly routine flight to measure the effect of a new engine setting supposed to enhance the engine efficiency at mach 2. It was a small increase of the rotation speed of the low pressure turbine increasing the air flow and, as a result, the thrust.
The flight test crews now regularly alternate their participation and their position in the cockpit for the pilots.
Today, Gilbert Defer is on the left side, myself on the right side, Michel R\xe9tif is the flight engineer, Claude Durand is the main flight engineer and Jean Conche is the engine flight engineer. With them is an official representative of the flight test centre, Hubert Guyonnet, seated in the cockpit's jump seat, he is in charge of radio testing.
We took off from Toulouse, accelerated to supersonic speed over the Atlantic near Arcachon continuing up to the north west of Ireland.
Two reheats, the 1 and the 3, are left on because the air temperature does not allow to maintain mach 2 without them.
Everything goes fine. During the previous flight, the crew experienced some strong turbulence, quite rare in the stratosphere and warned us about this. No problem was found on the aircraft.
We are on our way back to Toulouse off the coast of Ireland. Our program includes subsonic tests and we have to decelerate.
Gilbert is piloting the aircraft. Michel and the engineers notify us that everything is normal and ready for the deceleration and the descent.
We are at FL500 at mach 2 with an IAS of 530 kt, the maximum dynamic pressure in normal use.
On Concorde, the right hand seat is the place offering the less possibility to operate the systems. But here, we get busy by helping the others to follow the program and the checklists and by manipulating the secondary commands such as the landing gear, the droop nose, the radio navigation, comms, and some essential engine settings apart from the thrust leavers such as the reheat switches.
The normal procedure consists in stopping the reheat before lowering the throttle.
Gilbert asks me to do it. After, he will slowly reduce the throttle to avoid temporary heckler. Note that he did advise us during the training on the air intake to avoid to move the thrust leaver in case of engine surge.
As a safety measure, I shut down the reheat one by one, checking that everything goes fine for each one. Thus I switch off the reheat 1 with the light shock marking the thrust reduction. Then the 3\x85
Instantly, we are thrown in a crazy situation.
Deafening noise like a canon firing 300 times a minute next to us. Terrible shake. The cockpit, that looked like a submarine with the metallic and totally opaque visor obviously in the upper position, is shaken at a frequency of 5 oscillation a second and a crazy amplitude of about 4 to 5 G. To the point that we cannot see anymore, our eyes not being able to follow the movements.
Gilbert has a test pilot reaction, we have to get out of the maximum kinetic energy zone as fast as possible and to reduce speed immediately. He then moves the throttle to idle without any useless care.
During that time, I try, we all try to answer the question: what is going on? What is the cause of this and what can we do to stop it?
Suspecting an issue with the engines, I try to read the indicators on the centre control panel through the mist of my disturbed vision and in the middle of a rain of electric indicators falling from the roof. We cannot speak to each other through the intercom.
I vaguely see that the engines 3 and 4 seem to run slower than the 2 others, especially the 4. We have to do something. Gilbert is piloting the plane and is already busy. I have a stupid reaction dictated by the idea that I have to do something to stop that, while I can only reach a few commands that may be linked to the problem.
I first try to increase the thrust on number 4 engine. No effect so I reduce frankly and definitively. I desperately look for something to do from my right hand seat with a terrible feeling of being helpless and useless.
Then everything stops as suddenly as it started. How long did it last, 30 seconds, one minute?
By looking at the flight data records afterward, we saw that it only last\x85 12 seconds!
However, I have the feeling that I had time to think about tons of things, to do a lot of reasoning, assumption and to have searched and searched and searched\x85! It looked like my brain suddenly switched to a fastest mod of thinking. But, above all, it's the feeling of failure, the fact that I was not able to do anything and that I did not understand anything that remains stuck in my mind forever.
To comfort me, I have to say that nobody among the crew did understand anything either and was able to do anything, apart from Gilbert.
The aircraft slows down and the engine 3 that seemed to have shut down restart thanks to the auto ignition system. But the 4 is off indeed.
Michel makes a check of his instruments. He also notes that the engine 4 has shut down but the 4 air intakes work normally, which makes us feel better. After discussing together, we start to think that we probably faced some stratospheric turbulence of very high intensity, our experience in this altitude range being quite limited at that time. But nobody really believes in this explanation. Finally, at subsonic speed, mach 0.9, with all instruments looking normal, we try to restart engine 4 since we still have a long way to go to fly back to Toulouse.
Michel launches the process to restart the engine. It restarts, remains at a medium rotation speed and shuts down after 20 seconds, leaving us puzzled and a bit worried despite the fact that the instrument indicators are normal.
Gilbert then decide to give up and won't try to restart this engine anymore and Claude leaves his engineer station to have a look in a device installed on the prototype to inspect the landing gear and the engines when needed: an hypo-scope, a kind of periscope going out through the floor and not through the roof.
After a few seconds, we can hear him on the intercom:
"Shit! (stuttering) we have lost the intake number 4."
He then describes a wide opening in the air intake, the ramp seems to be missing and he can see some structural damages on the nacelle.
Gilbert reacts rapidly by further reducing the speed to limit even more the dynamic pressure.
But we don't know exactly the extent of the damage. Are the wing and the control surfaces damaged? What about engine 3?
We decide to fly back at a speed of 250 kts at a lower altitude and to divert toward Fairford where our british colleagues and the 002 are based. I inform everybody about the problem on the radio and tell them our intentions. However, I add that if no other problems occur, we will try to reach Toulouse since we still have enough fuel.
Flying off Fairford, since nothing unusual happened, we decide to go on toward Toulouse. All the possible diversion airport on the way have been informed by the flight test centre who follows us on their radar.
At low speed, knowing what happened to us and having nothing else to do but to wait for us, time passes slowly, very slowly and we don't talk much, each one of us thinking and trying to understand what happened. However, we keep watching closely after engine 3.
Personally, I remember the funny story of the poor guy who sees his house collapse when he flushes his toilets. I feel in the same situation.
Gilbert makes a precautionary landing since we don't rely much on engine 3 anymore. But everything goes fine.
At the parking, there is a lot of people waiting for us and, as soon as the engines stop, we can see a big rush toward the nacelles of the right hand side engines.
Gilbert and myself are the first to get off the plane and we are welcomed down the stairs by Andr\xe9 Turcat and Jean Franchi who came out from the crowd watching at the right hand side nacelle.
They both behave the same way, with a slow pace attitude, the same look, a mix of disbelief and frustration.
Andr\xe9 is the first to speak: "I can't believe we were not on this flight, really unlucky\x85". Yes, this flight was supposed to be just a routine flight\x85!
The condition of the nacelle is impressive. We come closer and everybody move aside for us with a look of disbelief and respect as if we were hell survivors.
The ramps of the intake 4, those 2 "dining tables", have completely disappeared leaving a hole where we can see the hydraulic jacks and the stub rod where the ramps were attached.
Indeed, only the ramps were missing, apparently ejected forward which was unbelievable knowing how fast we were flying. The ramp slipped under the nacelle causing some damages on it and on the hood of one of the elevon's servo control. Fortunately, the control did not suffer any damage.
What is left of the rear ramp seems to be blocked down inside the intake in front of the engine and we can see behind it the first blades of the compressor, or what is left of it, not much.
The engine swallowed a huge amount of metal but no vital parts of the aircraft has been damaged, no hydraulic leaks, no fuel leaks. I remembered at that time the stories of some B58 Hustler accident where the loss of an engine at mach 2 almost certainly ended with the complete loss of the aircraft. Our Concorde has only been shaken. This incident strengthened the trust I had in this plane. And I was not unhappy to have experienced this ordeal, especially when I saw the frustration on the face of Andr\xe9 Turcat and Jean Franchi.
But we had to understand what happened and how; and also why the ramp's fixing broke.
It didn't take much time to get the answers.
I unintentionally triggered the problem when shutting down the reheat of engine 3. The sudden stop of the fuel flow did of course stop the combustion and the back pressure behind the low pressure turbine. But, probably because of the modification made on the engine before the flight, the stop of the reheat has not been followed by the normal closing movement of the primary nozzle to compensate the pressure drop. So the low pressure turbine ran out of control, dragging down the low pressure compressor which reacts by surging.
Despite the opening of the spill door, the engine surge led to a sudden movement of the shockwaves in the air intake creating a surge in the intake itself. A similar surge happened in the adjacent intake 4 followed by a surge of the corresponding engine. This caused an excessive pressure above the ramps and the fixings of the intake 4 did not hold.
Since it was the first time we experienced a surge in the air intake, we had little knowledge of the stress it would create on the ramps. This led to miscalculation of the strength of the ramps's frames and they did brake.
Another mistake: instead of installing the motion detectors on the ramp itself, to make the production easier, they have been placed on the arms of the hydraulic jacks. This is why Michel R\xe9tif thought that the position of the ramps were correct. The hydraulic jacks did not suffer any damage and were still working normally even if the ramps were missing.
All the data recorded during this event helped us in redesigning the air intakes and the flight test program resumed three month later.
After this, we deliberately created dozen and dozen of air intake surge to fine tune the way to regulate them with digital calculator this time.
From now on, even if it was still very impressive, it was safe and their intensity was not comparable with what we experienced with the missing ramps.
However, a french president may kept a lasting memory of this, much later, during a flight back from Saudi Arabia. This time, I was on the left side, Gilbert on the right and Michel was still in the third seat\x85 But that's another story.
For me, the lasting impression of failing and being helpless during this incident made me wonder what a commercial pilot would have done in this situation. This plane was designed to be handled by standard commercial pilots and not only by the flight test pilots.
At that time, I was interested in taking in charge the management of a training center for the pilots of the future Airbus's clients. This event pushed me that way and I made it clear that I wanted to add the flight training on Concorde in this project. This has been agreed and I did it.
And the Concorde training program now covers the air intake surges and how to deal with them.
Jean PINET
Former test pilot
Member and former president of the Air and Space Academy
Accueil
This site has a database of thousand of concorde flights with the following datas: Date and time of the flight, airframe used, technical and commercial crews, guests, departure/arrival airports and flight type (regular, charter world tour...).
On top of that, many infos and stories around Concorde can also be found there.
I can't resist to translate one of those stories (I'm far from being a native english speaker or a professional translator; so forgive me for the misspellings and other translation mistakes). It is a report about one of the biggest incident that happened to the prototype 001 during the flight tests:
Shock of shockwaves
We were flying with Concorde at Mach 2 since 3 month already on both side of the Channel. The prototype 001 did outstrip 002 which was supposed to be the first to reach Mach 2.
Unfortunately, a technical issue delayed 002 and Brian Trubshaw fairly let Andr\xe9 Turcat be the first to reach Mach 2 with the 001 which was ready to go.
The flight tests were progressing fast and we were discovering a part of the atmosphere that military aircrafts hardly reached before. With Concorde, we were able to stay there for hours although limited by the huge fuel consumption of the prototypes.
The Olympus engines did not reached their nominal performance yet and, most of the time, we had to turn on the reheat in supersonic cruise to maintain Mach 2.
The reheat is what we call afterburner on military aircrafts. Fuel is injected between the last compressor stage of the low pressure turbine and the first exhaust nozzle. This increases the thrust for the whole engine and its nozzle.
The 4 reheats, one for each engine, are controlled by the piano switches behind the thrust leavers on the center pedestal between the two pilots. Air was fed into the engines through 4 air intakes, one for each engine, attached 2 by 2 to the 2 engine nacelle, one under each wing. The advantage in terms of drag reduction was obvious.
However, tests in wind tunnel showed that, at supersonic speed, if a problem happens on one engine, there was a great chance for the adjacent engine to be affected as well by the shockwave interference from one air intake to the other despite the presence the dividing wall between the two intakes. So we knew that an engine failure at mach 2 would result in the loss of 2 engines on the same side, resulting in a lateral movement leading to a strong sideslip that would likely impact the 2 remaining engines and transform the aircraft into the fastest glider in the world.
This is why an automatic anti sideslip device was developed and installed on the aircrafts.
The air intakes are very sophisticated. At mach 2, it creates a system of shockwaves that slows down the air from 600 m/sec in front of the aircraft to 200 m/sec in front of the engine while maintaining a very good thermodynamic performance. In supersonic cruise, the engines, operating at full capacity all the time, were sensitive to any perturbation and reacted violently with engine surge: the engine refusing the incoming air.
Stopping suddenly a flow of almost 200kg of air per second traveling at 600m/sec causes a few problems. As a result, a spill door was installed under the air intake and automatically opened in such event.
To control the system of shockwaves and obtain an efficiency of 0,96 in compression in the air intake, 2 articulated ramps, controlled by hydraulic jacks, are installed on the top of the air intakes in front of the engines. Each ramp is roughly the size of a big dining room table, and the 2 ramps, mechanically synchronized, move up or down following the instruction of an highly sophisticated computer that adapts the ramp position according to the mach number, the engine rating and other parameters such as skidding.
At that time, it was the less known part of the aircraft, almost only designed through calculation since no simulator, no wind tunnel, did allow a full scale test of the system.
The control of the system was analog and very complex but it was not easy to tune and we were moving ahead with a lot of caution in our test at mach 2.
On the 26th of January 1971, we were doing a nearly routine flight to measure the effect of a new engine setting supposed to enhance the engine efficiency at mach 2. It was a small increase of the rotation speed of the low pressure turbine increasing the air flow and, as a result, the thrust.
The flight test crews now regularly alternate their participation and their position in the cockpit for the pilots.
Today, Gilbert Defer is on the left side, myself on the right side, Michel R\xe9tif is the flight engineer, Claude Durand is the main flight engineer and Jean Conche is the engine flight engineer. With them is an official representative of the flight test centre, Hubert Guyonnet, seated in the cockpit's jump seat, he is in charge of radio testing.
We took off from Toulouse, accelerated to supersonic speed over the Atlantic near Arcachon continuing up to the north west of Ireland.
Two reheats, the 1 and the 3, are left on because the air temperature does not allow to maintain mach 2 without them.
Everything goes fine. During the previous flight, the crew experienced some strong turbulence, quite rare in the stratosphere and warned us about this. No problem was found on the aircraft.
We are on our way back to Toulouse off the coast of Ireland. Our program includes subsonic tests and we have to decelerate.
Gilbert is piloting the aircraft. Michel and the engineers notify us that everything is normal and ready for the deceleration and the descent.
We are at FL500 at mach 2 with an IAS of 530 kt, the maximum dynamic pressure in normal use.
On Concorde, the right hand seat is the place offering the less possibility to operate the systems. But here, we get busy by helping the others to follow the program and the checklists and by manipulating the secondary commands such as the landing gear, the droop nose, the radio navigation, comms, and some essential engine settings apart from the thrust leavers such as the reheat switches.
The normal procedure consists in stopping the reheat before lowering the throttle.
Gilbert asks me to do it. After, he will slowly reduce the throttle to avoid temporary heckler. Note that he did advise us during the training on the air intake to avoid to move the thrust leaver in case of engine surge.
As a safety measure, I shut down the reheat one by one, checking that everything goes fine for each one. Thus I switch off the reheat 1 with the light shock marking the thrust reduction. Then the 3\x85
Instantly, we are thrown in a crazy situation.
Deafening noise like a canon firing 300 times a minute next to us. Terrible shake. The cockpit, that looked like a submarine with the metallic and totally opaque visor obviously in the upper position, is shaken at a frequency of 5 oscillation a second and a crazy amplitude of about 4 to 5 G. To the point that we cannot see anymore, our eyes not being able to follow the movements.
Gilbert has a test pilot reaction, we have to get out of the maximum kinetic energy zone as fast as possible and to reduce speed immediately. He then moves the throttle to idle without any useless care.
During that time, I try, we all try to answer the question: what is going on? What is the cause of this and what can we do to stop it?
Suspecting an issue with the engines, I try to read the indicators on the centre control panel through the mist of my disturbed vision and in the middle of a rain of electric indicators falling from the roof. We cannot speak to each other through the intercom.
I vaguely see that the engines 3 and 4 seem to run slower than the 2 others, especially the 4. We have to do something. Gilbert is piloting the plane and is already busy. I have a stupid reaction dictated by the idea that I have to do something to stop that, while I can only reach a few commands that may be linked to the problem.
I first try to increase the thrust on number 4 engine. No effect so I reduce frankly and definitively. I desperately look for something to do from my right hand seat with a terrible feeling of being helpless and useless.
Then everything stops as suddenly as it started. How long did it last, 30 seconds, one minute?
By looking at the flight data records afterward, we saw that it only last\x85 12 seconds!
However, I have the feeling that I had time to think about tons of things, to do a lot of reasoning, assumption and to have searched and searched and searched\x85! It looked like my brain suddenly switched to a fastest mod of thinking. But, above all, it's the feeling of failure, the fact that I was not able to do anything and that I did not understand anything that remains stuck in my mind forever.
To comfort me, I have to say that nobody among the crew did understand anything either and was able to do anything, apart from Gilbert.
The aircraft slows down and the engine 3 that seemed to have shut down restart thanks to the auto ignition system. But the 4 is off indeed.
Michel makes a check of his instruments. He also notes that the engine 4 has shut down but the 4 air intakes work normally, which makes us feel better. After discussing together, we start to think that we probably faced some stratospheric turbulence of very high intensity, our experience in this altitude range being quite limited at that time. But nobody really believes in this explanation. Finally, at subsonic speed, mach 0.9, with all instruments looking normal, we try to restart engine 4 since we still have a long way to go to fly back to Toulouse.
Michel launches the process to restart the engine. It restarts, remains at a medium rotation speed and shuts down after 20 seconds, leaving us puzzled and a bit worried despite the fact that the instrument indicators are normal.
Gilbert then decide to give up and won't try to restart this engine anymore and Claude leaves his engineer station to have a look in a device installed on the prototype to inspect the landing gear and the engines when needed: an hypo-scope, a kind of periscope going out through the floor and not through the roof.
After a few seconds, we can hear him on the intercom:
"Shit! (stuttering) we have lost the intake number 4."
He then describes a wide opening in the air intake, the ramp seems to be missing and he can see some structural damages on the nacelle.
Gilbert reacts rapidly by further reducing the speed to limit even more the dynamic pressure.
But we don't know exactly the extent of the damage. Are the wing and the control surfaces damaged? What about engine 3?
We decide to fly back at a speed of 250 kts at a lower altitude and to divert toward Fairford where our british colleagues and the 002 are based. I inform everybody about the problem on the radio and tell them our intentions. However, I add that if no other problems occur, we will try to reach Toulouse since we still have enough fuel.
Flying off Fairford, since nothing unusual happened, we decide to go on toward Toulouse. All the possible diversion airport on the way have been informed by the flight test centre who follows us on their radar.
At low speed, knowing what happened to us and having nothing else to do but to wait for us, time passes slowly, very slowly and we don't talk much, each one of us thinking and trying to understand what happened. However, we keep watching closely after engine 3.
Personally, I remember the funny story of the poor guy who sees his house collapse when he flushes his toilets. I feel in the same situation.
Gilbert makes a precautionary landing since we don't rely much on engine 3 anymore. But everything goes fine.
At the parking, there is a lot of people waiting for us and, as soon as the engines stop, we can see a big rush toward the nacelles of the right hand side engines.
Gilbert and myself are the first to get off the plane and we are welcomed down the stairs by Andr\xe9 Turcat and Jean Franchi who came out from the crowd watching at the right hand side nacelle.
They both behave the same way, with a slow pace attitude, the same look, a mix of disbelief and frustration.
Andr\xe9 is the first to speak: "I can't believe we were not on this flight, really unlucky\x85". Yes, this flight was supposed to be just a routine flight\x85!
The condition of the nacelle is impressive. We come closer and everybody move aside for us with a look of disbelief and respect as if we were hell survivors.
The ramps of the intake 4, those 2 "dining tables", have completely disappeared leaving a hole where we can see the hydraulic jacks and the stub rod where the ramps were attached.
Indeed, only the ramps were missing, apparently ejected forward which was unbelievable knowing how fast we were flying. The ramp slipped under the nacelle causing some damages on it and on the hood of one of the elevon's servo control. Fortunately, the control did not suffer any damage.
What is left of the rear ramp seems to be blocked down inside the intake in front of the engine and we can see behind it the first blades of the compressor, or what is left of it, not much.
The engine swallowed a huge amount of metal but no vital parts of the aircraft has been damaged, no hydraulic leaks, no fuel leaks. I remembered at that time the stories of some B58 Hustler accident where the loss of an engine at mach 2 almost certainly ended with the complete loss of the aircraft. Our Concorde has only been shaken. This incident strengthened the trust I had in this plane. And I was not unhappy to have experienced this ordeal, especially when I saw the frustration on the face of Andr\xe9 Turcat and Jean Franchi.
But we had to understand what happened and how; and also why the ramp's fixing broke.
It didn't take much time to get the answers.
I unintentionally triggered the problem when shutting down the reheat of engine 3. The sudden stop of the fuel flow did of course stop the combustion and the back pressure behind the low pressure turbine. But, probably because of the modification made on the engine before the flight, the stop of the reheat has not been followed by the normal closing movement of the primary nozzle to compensate the pressure drop. So the low pressure turbine ran out of control, dragging down the low pressure compressor which reacts by surging.
Despite the opening of the spill door, the engine surge led to a sudden movement of the shockwaves in the air intake creating a surge in the intake itself. A similar surge happened in the adjacent intake 4 followed by a surge of the corresponding engine. This caused an excessive pressure above the ramps and the fixings of the intake 4 did not hold.
Since it was the first time we experienced a surge in the air intake, we had little knowledge of the stress it would create on the ramps. This led to miscalculation of the strength of the ramps's frames and they did brake.
Another mistake: instead of installing the motion detectors on the ramp itself, to make the production easier, they have been placed on the arms of the hydraulic jacks. This is why Michel R\xe9tif thought that the position of the ramps were correct. The hydraulic jacks did not suffer any damage and were still working normally even if the ramps were missing.
All the data recorded during this event helped us in redesigning the air intakes and the flight test program resumed three month later.
After this, we deliberately created dozen and dozen of air intake surge to fine tune the way to regulate them with digital calculator this time.
From now on, even if it was still very impressive, it was safe and their intensity was not comparable with what we experienced with the missing ramps.
However, a french president may kept a lasting memory of this, much later, during a flight back from Saudi Arabia. This time, I was on the left side, Gilbert on the right and Michel was still in the third seat\x85 But that's another story.
For me, the lasting impression of failing and being helpless during this incident made me wonder what a commercial pilot would have done in this situation. This plane was designed to be handled by standard commercial pilots and not only by the flight test pilots.
At that time, I was interested in taking in charge the management of a training center for the pilots of the future Airbus's clients. This event pushed me that way and I made it clear that I wanted to add the flight training on Concorde in this project. This has been agreed and I did it.
And the Concorde training program now covers the air intake surges and how to deal with them.
Jean PINET
Former test pilot
Member and former president of the Air and Space Academy
Last edited by NHerby; 9th May 2013 at 17:24 .
10th Jun 2015, 04:28
permalink Post: 1890
Here's a link to the six development aircraft, with pix of all of them.
CONCORDE SST : PROTOTYPE FLEET
Several had different paint schemes throughout their history, so that may not be definitive. But there are variations that can narrow down which might be in your painting: long or short tailcone, and small window or large greenhouse cockpit visor.
Three of the six are British G registrations, and three have French F-numbers. Three have "...01" production numbers. As ChristiaanJ says, none would be registered "1-GEE" - but that might have been something added for a specific test flight or for some other reason unrelated to registration. They were repainted occasionally (including one painted in BA livery on one side and AF livery on the other, for a time.)
CONCORDE SST : PROTOTYPE FLEET
Several had different paint schemes throughout their history, so that may not be definitive. But there are variations that can narrow down which might be in your painting: long or short tailcone, and small window or large greenhouse cockpit visor.
Three of the six are British G registrations, and three have French F-numbers. Three have "...01" production numbers. As ChristiaanJ says, none would be registered "1-GEE" - but that might have been something added for a specific test flight or for some other reason unrelated to registration. They were repainted occasionally (including one painted in BA livery on one side and AF livery on the other, for a time.)
15th Jun 2015, 21:44
permalink Post: 1898
@ BN2A
I'm sure the real experts will "adjust" my understanding - but I believe Concorde, loaded for the transatlantic "Sierra" routes, could hit about 5000 fpm peak VS when climbing at 400 KIAS between ~10,000 and ~28,000 feet (wherever 400 KIAS = M 0.99). Leaving a coastal airport (New York, Barbados, Dakar), she would quickly be clear of land and could more or less transition directly through Mach 1 as soon as she reached 28-30,000 feet.
Those 4 Olympus engines could maintain Mach 2 with no afterburner at 50,000+ feet, so they had tons of excess power down low. Again my understanding is that they stayed at 100% dry thrust from brake release until TOD (except for subsonic cruise segments), with the AB added for takeoff, and when accelerating from Mach 0.96 through Mach 1.7.
Mach 2.00 was reached in about 30 minutes @ ~51,300 feet, depending on atmospherics - a relatively long slow slog compared to the initial climb and acceleration.
From inland airports such PDG or Heathrow, there was a "pause" for level subsonic cruise (M 0.94-0.96) in the high 20s until clear of the coastline by 20 miles (over La Manche or the mouth of the Bristol Channel.)
@ leb001 - greenhouse visor, BA livery, and short tail - probably G-AXDN (aircraft 101). Although I'll defer to the experts, as always.
I'm sure the real experts will "adjust" my understanding - but I believe Concorde, loaded for the transatlantic "Sierra" routes, could hit about 5000 fpm peak VS when climbing at 400 KIAS between ~10,000 and ~28,000 feet (wherever 400 KIAS = M 0.99). Leaving a coastal airport (New York, Barbados, Dakar), she would quickly be clear of land and could more or less transition directly through Mach 1 as soon as she reached 28-30,000 feet.
Those 4 Olympus engines could maintain Mach 2 with no afterburner at 50,000+ feet, so they had tons of excess power down low. Again my understanding is that they stayed at 100% dry thrust from brake release until TOD (except for subsonic cruise segments), with the AB added for takeoff, and when accelerating from Mach 0.96 through Mach 1.7.
Mach 2.00 was reached in about 30 minutes @ ~51,300 feet, depending on atmospherics - a relatively long slow slog compared to the initial climb and acceleration.
From inland airports such PDG or Heathrow, there was a "pause" for level subsonic cruise (M 0.94-0.96) in the high 20s until clear of the coastline by 20 miles (over La Manche or the mouth of the Bristol Channel.)
@ leb001 - greenhouse visor, BA livery, and short tail - probably G-AXDN (aircraft 101). Although I'll defer to the experts, as always.