13th Aug 2010, 18:53
permalink Post: 4
Point taken GF, but it was discovered during development flying that that the Olympus 593 could be relit, given sufficient IAS, at almost any altitude within the normal flight envelope. The variable inlet would even be automatically scheduled, as a funcion of N1, in order to improve relight performance at lower Mach numbers. I certainly agree that you would decelerate and lose altitude fairly quickly under these conditions, however a multiple flame out was never experienced during the entire 34 years of Concorde flight testing and airline operation. There was, as a matter of interest an un-commanded deployment of a Concorde RAT AT MACH 2!! (The first indications of the event were when the cabin crew complained about 'a loud propeller sound under the rear cabin floor'. A quick scan of the F/E's panel revealed the truth of the matter). The aircraft landed at JFK without incident, and the RAT itself, apart from a very small leak on one of the hydraulic pumps, was more or less un-phased by the event. Although it sounds horrific, a prop rotating in a Mach 2 airstream, the IAS it 'felt' would be no more than 530 KTS at any time. The RAT was of course replaced before the aircraft flew back to LHR.
Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff.
Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world.
Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff.
Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world.
22nd Aug 2010, 01:47
permalink Post: 56
Biggles78
You are right on the button. Under NORMAL circumstances, Concorde never flew supersonically in level flight. You would always follow the Vmo bug on the ASI during the supersonic climb. (The ASI pointer actually nudged into the bug; it was a beautiful design). Initially this would be at a constant Vc of 400 kts, the 400 KT segment then went off towards 530 KTS as you climbed. You then 'stuck' to 530 knots until a fraction over 50,000', when 530 KTS became Mach 2. You would then continue the climb at between Mach 2 and around Mach 2.02, depending on the temperature of the day. (the colder the temperature, the faster you tended to fly). There was an extremely complex AFCS mode for the supersonic climb, that I promise to cover in anaother post.
So yes, on the whole, TOC did equal TOD.
The 'subsonic climb' wasn't quite as you thought; you'd normally subsonic climb to FL280, staying there (at Mach 0.95) until the acceleration point. Mach 0.95 was 'subsonic cruise'. But you were on the right track.
Oh, and NOPE, they never boomed us either
Nick Thomas
Keeping the powerplants as separate as possible was a major design headache, but generally they were just that; there was a titanium centre wall between the two engines and a really substantial heatshield above the engine also, to protect the wing above. To give you an idea how all this worked in practice, in 1980 G-BOAF, flying at Mach 2 between JFK and LHR had a major failure of one of the engines, caused by a defective material ingot used in the forging of one of the 1st stage LP compressor blades; which was subsequently shed. (The analysis done by Rolls Royce ensured that no such incident ever happened again in the life of Concorde). The resulting mayhem terminated in a large amount of engine debris flying around, and a titanium fire burning in the engine bay also. The aircraft however decelerated and landed at Shannon safely. On inspection, although there was extensive damage found in the engine bay, the adjacent engine was completely unmarked, protected by the titanium centre wall, and more importantly, when the heat shield werer removed, the wing was found to be completely undamaged!
The only problem you ever had with the dual nacelle arrangement was if you had an engine surge above Mach 1.6 (These were relatively rare, but could happen with an engine or intake control system malfuntion). If one engine surged, the other would surge in sympathy, because of the shock system being expelled from one intake severely distorting the airflow into it's neighbour. These surges were loud, quite scary (to the crew that is, most passengers never noticed much), but in themselves did no damage at all. Delicate movement of the throttles (employed during the subsequent surge drill) would invariably restore peace and harmony again to all. (The intake on Concorde was self-starting, so no manual movement of the intake variable surfaces should be needed in this event). After this was over, normal flying was resumed again As I said before, these events were relatively rare, but when they did occur, they would be dealt with smartly and professionally; the engine and intake structure being undamaged. (Post surge inspetion checks were always carried out on the ground after an event, on both engine and intake, but nothing much was EVER found).
The reduction of fuel flow as you climbed was quite interesting. Although the throttles would be 'at the wall' (dry power remember), the electronic control system was constantly winding fuel off as a function of Static Air Temperature, as well as falling Total Pressure. The system was always 'tweaking' as you climbed, and you only used as much fuel as you really needed to stay at Mach 2. There were various ratings that would also be manually selected at various phases of flight; each rating change 'detuned' the engine slightly, so yes, you did not run the engine when flying fast at anywhere near the levels you did at lower speeds/altitudes. The engine final ratings were changed from 'Climb' to 'Cruise' manually at FL 500, just as you hit Mach 2).
Quote:
| Am I right or even slightly so in thinking that cruise climb and cruise descent was the flight and there was minimal actual level cruise in the "pond" crossing? |
So yes, on the whole, TOC did equal TOD.
The 'subsonic climb' wasn't quite as you thought; you'd normally subsonic climb to FL280, staying there (at Mach 0.95) until the acceleration point. Mach 0.95 was 'subsonic cruise'. But you were on the right track.
Oh, and NOPE, they never boomed us either
Nick Thomas
Quote:
| If an engine had a fire or an explosive failure; it would seem on the face of it that the adjacent engine could easily be affected. As everything on Concorde has a sound technical reason. I have been wondering what that reason or reasons was? and also if there was any inbuilt dividing protection between engines on the same wing? |
The only problem you ever had with the dual nacelle arrangement was if you had an engine surge above Mach 1.6 (These were relatively rare, but could happen with an engine or intake control system malfuntion). If one engine surged, the other would surge in sympathy, because of the shock system being expelled from one intake severely distorting the airflow into it's neighbour. These surges were loud, quite scary (to the crew that is, most passengers never noticed much), but in themselves did no damage at all. Delicate movement of the throttles (employed during the subsequent surge drill) would invariably restore peace and harmony again to all. (The intake on Concorde was self-starting, so no manual movement of the intake variable surfaces should be needed in this event). After this was over, normal flying was resumed again As I said before, these events were relatively rare, but when they did occur, they would be dealt with smartly and professionally; the engine and intake structure being undamaged. (Post surge inspetion checks were always carried out on the ground after an event, on both engine and intake, but nothing much was EVER found).
Quote:
| Would I also be right to assume that the max power delivered by the engines would reduce at altitude, thus even if the engines were run at near to available max power at high altitude it would be no way near the max power at lower levels? |
22nd Aug 2010, 03:45
permalink Post: 60
Nick Thomas
... My other query concerns the FE. I understand that he set take off power etc...
Actually the F/E didn’t set T/O power, but did set most of the other power settings.
Broadly speaking, taxy-out to gear up, and gear down to engine shut down, the handling pilot operated the throttles. At other times, it was (almost) always the F/E.
Bear in mind that several of the routine engine power changes were effected through controls other than the throttles. For instance, selection of the re-heats, engine control schedules, engine ratings and intake lanes were all switch selections.
... I also understand that he also checked the pilots inputs into the INS system...
Correct, using INS3.
...So was he/she also a qualified pilot?..
No, they were professional flight engineers, who held a Flight Engineers Licence; they were not pilots biding their time before moving to the right hand seat.
I believe one or two may have held a PPL, but that was purely incidental, not a requirement.
All of the Concorde FEs had spent years on the VC10, B707, DC10, L10-11 or B747 fleets before coming to Concorde.
Biggles78
...Am I right or even slightly so in thinking that cruise climb and cruise descent was the flight...
Cruise climb, yes. Cruise descent, no.
...and there was minimal actual level cruise in the "pond" crossing?..
Correct, any level flight in the “cruise”, was just coincidence, probably caused by the outside air temperature increasing very gradually. Typically, she drifted up at around 30 to 50 fpm, but, if encountering warmer air, she would start to drift back down, in order to maintain M2.0.
... As you have said, fuel flow was reduced the higher you got. I think it was 5T per powerplant at FL500 down to 4.1T at FL600...
Rather optimistic figures for FL500 I’d have said! 6,000kg/hr/engine would have been nearer the mark!
...I am curious to see how much less fuel would have been used at the higher FLs considering it was reduced by 900Kg/hr for just 10K feet...
The reason the fuel flows dropped so much at the higher altitudes was that the aircraft had to be a lot lighter before she would get up there. It was her lighter weight that was the primary reason for the reduced fuel flows, not the higher altitude.
Forgive me if I’ve misunderstood you, but in her cruise climb, Concorde was flown at her optimum speed (M2.00) with (constant) optimum power set (max cruise power) and so (assuming a constant OAT above the tropopause) the only thing which affected her cruising altitude was her weight.
So, in theory at least, in cruise climb, she was always at her optimum altitude.
Any variation from that optimum altitude, such as a premature climb to higher altitudes, would have cost fuel, not saved it.
... How much of the descent was carried out while supersonic...
At the decel point, the cruise climb ceased and she was flown level at constant altitude. The F/E partially throttled back the engines and she stayed in level flight until her speed reduced to 350kts IAS, typically M1.5.
This took about 50nm, and most of the passengers would have sworn that they were already descending.
She then descended at 350kts IAS, meaning the Mach number would reduce constantly. On a straight in approach to JFK, with no subsonic cruise section, she would become subsonic descending through (around) FL350.
For a straight in approach, in zero wind, on a standard day, from FL600 to touchdown, typical figures would be something like a track distance of around 200nm, flying time of 22 minutes and 3,500kg of fuel.
Into LHR, she had to be subsonic much further away from her destination, and then had a subsonic cruise section on airways, so a slightly different procedure was used, and approaching FL410 she was slowed still further, becoming subsonic around FL400.
Anonymous
In response to your PM, earlier posters were correct in what they posted, however the manual reversion they refer to is a reversion from electrical to mechanical signalling to the flying controls.
There was no way to operate the flying controls manually in the absence of hydraulic power.
... My other query concerns the FE. I understand that he set take off power etc...
Actually the F/E didn’t set T/O power, but did set most of the other power settings.
Broadly speaking, taxy-out to gear up, and gear down to engine shut down, the handling pilot operated the throttles. At other times, it was (almost) always the F/E.
Bear in mind that several of the routine engine power changes were effected through controls other than the throttles. For instance, selection of the re-heats, engine control schedules, engine ratings and intake lanes were all switch selections.
... I also understand that he also checked the pilots inputs into the INS system...
Correct, using INS3.
...So was he/she also a qualified pilot?..
No, they were professional flight engineers, who held a Flight Engineers Licence; they were not pilots biding their time before moving to the right hand seat.
I believe one or two may have held a PPL, but that was purely incidental, not a requirement.
All of the Concorde FEs had spent years on the VC10, B707, DC10, L10-11 or B747 fleets before coming to Concorde.
Biggles78
...Am I right or even slightly so in thinking that cruise climb and cruise descent was the flight...
Cruise climb, yes. Cruise descent, no.
...and there was minimal actual level cruise in the "pond" crossing?..
Correct, any level flight in the “cruise”, was just coincidence, probably caused by the outside air temperature increasing very gradually. Typically, she drifted up at around 30 to 50 fpm, but, if encountering warmer air, she would start to drift back down, in order to maintain M2.0.
... As you have said, fuel flow was reduced the higher you got. I think it was 5T per powerplant at FL500 down to 4.1T at FL600...
Rather optimistic figures for FL500 I’d have said! 6,000kg/hr/engine would have been nearer the mark!
...I am curious to see how much less fuel would have been used at the higher FLs considering it was reduced by 900Kg/hr for just 10K feet...
The reason the fuel flows dropped so much at the higher altitudes was that the aircraft had to be a lot lighter before she would get up there. It was her lighter weight that was the primary reason for the reduced fuel flows, not the higher altitude.
Forgive me if I’ve misunderstood you, but in her cruise climb, Concorde was flown at her optimum speed (M2.00) with (constant) optimum power set (max cruise power) and so (assuming a constant OAT above the tropopause) the only thing which affected her cruising altitude was her weight.
So, in theory at least, in cruise climb, she was always at her optimum altitude.
Any variation from that optimum altitude, such as a premature climb to higher altitudes, would have cost fuel, not saved it.
... How much of the descent was carried out while supersonic...
At the decel point, the cruise climb ceased and she was flown level at constant altitude. The F/E partially throttled back the engines and she stayed in level flight until her speed reduced to 350kts IAS, typically M1.5.
This took about 50nm, and most of the passengers would have sworn that they were already descending.
She then descended at 350kts IAS, meaning the Mach number would reduce constantly. On a straight in approach to JFK, with no subsonic cruise section, she would become subsonic descending through (around) FL350.
For a straight in approach, in zero wind, on a standard day, from FL600 to touchdown, typical figures would be something like a track distance of around 200nm, flying time of 22 minutes and 3,500kg of fuel.
Into LHR, she had to be subsonic much further away from her destination, and then had a subsonic cruise section on airways, so a slightly different procedure was used, and approaching FL410 she was slowed still further, becoming subsonic around FL400.
Anonymous
In response to your PM, earlier posters were correct in what they posted, however the manual reversion they refer to is a reversion from electrical to mechanical signalling to the flying controls.
There was no way to operate the flying controls manually in the absence of hydraulic power.
24th Aug 2010, 15:56
permalink Post: 94
There were questions about the JFK 31L take-off.
I think this is it....
YouTube - Concorde British Airways take-off
CJ
PS The YouTube legend says last t/o from Heathrow, obviously wrong.
I think this is it....
YouTube - Concorde British Airways take-off
CJ
PS The YouTube legend says last t/o from Heathrow, obviously wrong.
24th Aug 2010, 18:13
permalink Post: 96
Attitudes
Always more nose up than a conventional a/c.
As you note, about 4 in the CRZ. About 10.5 degs on approach.
As part of the performance calcs we calculated a 'theta 2' value of pitch. This was bugged on the ADI with a little bug controlled from a thumbwheel on the yoke - at all speeds very accurate pitch control was required, hance this device and the ADI being calibrated in 1 degree increments.
Theta 2 was attitude reqd to obtain V2 in the first segment with one engine out, i.e. the target attitude if an engine failed after V1. Once the gear was up (second segment) one would pitch up a little to hold V2 until 600ft then start initial accel.
On all engines, one held it until 250kts then pitched up to maintain that speed. You'd typically reach it before passing over the M25 departing LHR to the West.
In all cases, as soon as SID altitude or noise abatement limits had been reached you went to the barber's pole asap (400kts initially) as this was where best performance lay.
As you note, about 4 in the CRZ. About 10.5 degs on approach.
As part of the performance calcs we calculated a 'theta 2' value of pitch. This was bugged on the ADI with a little bug controlled from a thumbwheel on the yoke - at all speeds very accurate pitch control was required, hance this device and the ADI being calibrated in 1 degree increments.
Theta 2 was attitude reqd to obtain V2 in the first segment with one engine out, i.e. the target attitude if an engine failed after V1. Once the gear was up (second segment) one would pitch up a little to hold V2 until 600ft then start initial accel.
On all engines, one held it until 250kts then pitched up to maintain that speed. You'd typically reach it before passing over the M25 departing LHR to the West.
In all cases, as soon as SID altitude or noise abatement limits had been reached you went to the barber's pole asap (400kts initially) as this was where best performance lay.
24th Aug 2010, 22:49
permalink Post: 101
ChristiaanJ
aaah yes, Max Climb/Max Cruise modes. I'd not forgotten this my friend, I was going to say a few words about that in a future post, but maybe we can do that now. (And I'd love to hear more of your comments on this here too, ChristiaanJ). The intake and autopilot modifications were in a way complimentary it's true, but really dealt with separate problems, at least in my view:
The intake control unit software change (a change to the control law that limited engine N1 as a function of intake local Mach number, Mo, and inlet total temperature, T1) was able to put an absolute limit on aircraft achievable Mach number during Mmo overshoots, but it would not PREVENT Mmo overshoots occurring altogether, it was more of a safety brake. This particular overspeed problem manifested itself well before route proving, and in fact the intake system 'fix' resulted in the Thrust Auto Reduce System being deleted, electronic control boxes and all. The TAR system was fitted on all development aircraft equiped with the digital intake system, and it tried (in vain) to limit extreme Mach overshoots. The production aircraft retained the TAR wiring and locked out circuit breakers, as well as two vacant spaces on the electronic racks. The prime reason for all these efforts were that some of the rapid excessive Mach overshoots quite often drove the intake into surge; the modification to this N1 limiter control enabled engine mass flow to be controlled in such a way that these surges could be prevented during temperature shears. The aircraft Mach limit was an extremely useful fringe benefit.
The AFCS mode change from what was Max Op and Max Op Soft (always loved that name) to Max Climb/Max Cruise was at a stroke able to deal with the regular Mmo overspeeds that kept on occuring during, as you say, the route proving trials of 1975, when British aircraft G-BOAC and the French aircrfraft F-BTSD carried out pre entry into service evaluation flights, SD sadly was the aircraft that was tragically lost at Gonez in July 2000). The Max Climb/Max Cruise AFCS mode combo is a mode like no other that I've personally seen before or since anywhere, (it for instance resulted an elsewhere taboo; an autopilot and an autothrotte working together IN A SPEED MODE).
This problem encountered primarily at lower lattitudes, (for example, G-BOAC doing route proving flights out of Singapore), occurring initially as the aircraft reached Mach 2. It was termed 'the insurmountable problem', but the AFCS designers (such as ChristiaanJ) fortunately did not have 'insurmountable problems' in their vocabulary. The issue was that the aircraft would have been climbing rapidly at Vmo of 530 KTS, with throttles at the gate as usual, At exactly 50,189' we hit what was known as 'the corner point' in the flight envelope, where 530 KTS IAS equated to Mach 2 exactly. Max Op mode would then 'let go' of the Vmo segment, and try and control the aircraft to Mach 2. (As the aircraft climbed, Vmo itself would progreesively decrease in order to equate to Mmo, or 2.04 Mach). But in very cold conditions, the aircraft still 'wanting' to accelerate, and the simple Max Op/Max Op Soft modes just could not cope with gentle pitch changes alone. The problem became even bigger during the cruise/climb when severe temperature shears occured, and routinely regular Mmo exceedences occured. Something had to be done, and something WAS done and how; enter Max Climb/Max Cruise. It was really a classic piece of design, where the aircraft would do the initial supersonic climb in Max Climb mode. This mode itself was relatively simple, in that it was more or less a Vmo -Vc hold mode. That meant that the difference at selection between indicated airspeed, Vc and Vmo would be maintained, with a vernier datum adjust to this being available. In practice this mode was selected pretty much at Vmo, so datum adjusting was not always required. Now comes the clever part; the autothrottle, this would operate in standy mode at this point, just waiting there doing nothing, with the throttles at maximum as before. So the aircraft would now climb as Vmo increased to 530 KTS, and then following a now constant Vmo of 530 KTS until the magic 'corner point' (51, 189' remember). Now all hell would break loose; the mode would automatically change to Max Cruise, the autothrottle would also be automaically selected to Mach Hold mode (initially datumed here to Mach 2) and the throttles would retard, attempting to hold this Mach 2 datum, and the autopilot is commands a 'fly up' signal, over a 20 second lag period to 600'/minute. Now comes an even cleverer (?) part; the autothrottle Mach Hold datum is gradually increased over a 100 second period towards Mach 2.02, and so in stable conditions the throttles would now gradually increase again until they once more reach the maximum limit. At this point, the autothrottles now come out of Mach Hold mode and back into the waiting in the wings standby mode. The autopilot would now cancel it's 600' fly up, demand, returning to a datum of Mach 2. There was a little more complexity built in also, where the difference between the 'commanded' and actual vertical speeds offset the autoplilot Mach 2 datum. This would apply whether the autothrottle had cut in (+600'/min demand) or with the throttles back at maximum (0'/minute demand. A positive climb error tweaked the cruise Mach up slightly, a negative error (eg. in a turn) the converse was true. The effect of all of this complexity was that the aircraft itself could 'scan' until it settled at a point where the throttles could be at maximum, and the speed between Mach 2 and 2.02. On the North Atlantic, with warmer ISA temperatures, there was usually just the initial routine with the autothrottle as you hit the corner point. However at lower lattitudes (eg. LHR BGI) there could be a few initial autothrottle intercepts before things settled down. This whole incredible routine completely took care of the insurmountable problem, a problem that was shown not only to be insurmountable, but was put to bed forever, by people like ChristiaanJ.
I hope that my explanation here does not sound too much like gibberish.
EXWOK
I think you've guessed right as far as my identity goes; it's great that it's not just Concorde pilots I can bore the socks off now
PS. I bet the ex-SEOs LOVED your comments
Dude
aaah yes, Max Climb/Max Cruise modes. I'd not forgotten this my friend, I was going to say a few words about that in a future post, but maybe we can do that now. (And I'd love to hear more of your comments on this here too, ChristiaanJ). The intake and autopilot modifications were in a way complimentary it's true, but really dealt with separate problems, at least in my view:
The intake control unit software change (a change to the control law that limited engine N1 as a function of intake local Mach number, Mo, and inlet total temperature, T1) was able to put an absolute limit on aircraft achievable Mach number during Mmo overshoots, but it would not PREVENT Mmo overshoots occurring altogether, it was more of a safety brake. This particular overspeed problem manifested itself well before route proving, and in fact the intake system 'fix' resulted in the Thrust Auto Reduce System being deleted, electronic control boxes and all. The TAR system was fitted on all development aircraft equiped with the digital intake system, and it tried (in vain) to limit extreme Mach overshoots. The production aircraft retained the TAR wiring and locked out circuit breakers, as well as two vacant spaces on the electronic racks. The prime reason for all these efforts were that some of the rapid excessive Mach overshoots quite often drove the intake into surge; the modification to this N1 limiter control enabled engine mass flow to be controlled in such a way that these surges could be prevented during temperature shears. The aircraft Mach limit was an extremely useful fringe benefit.
The AFCS mode change from what was Max Op and Max Op Soft (always loved that name) to Max Climb/Max Cruise was at a stroke able to deal with the regular Mmo overspeeds that kept on occuring during, as you say, the route proving trials of 1975, when British aircraft G-BOAC and the French aircrfraft F-BTSD carried out pre entry into service evaluation flights, SD sadly was the aircraft that was tragically lost at Gonez in July 2000). The Max Climb/Max Cruise AFCS mode combo is a mode like no other that I've personally seen before or since anywhere, (it for instance resulted an elsewhere taboo; an autopilot and an autothrotte working together IN A SPEED MODE).
This problem encountered primarily at lower lattitudes, (for example, G-BOAC doing route proving flights out of Singapore), occurring initially as the aircraft reached Mach 2. It was termed 'the insurmountable problem', but the AFCS designers (such as ChristiaanJ) fortunately did not have 'insurmountable problems' in their vocabulary. The issue was that the aircraft would have been climbing rapidly at Vmo of 530 KTS, with throttles at the gate as usual, At exactly 50,189' we hit what was known as 'the corner point' in the flight envelope, where 530 KTS IAS equated to Mach 2 exactly. Max Op mode would then 'let go' of the Vmo segment, and try and control the aircraft to Mach 2. (As the aircraft climbed, Vmo itself would progreesively decrease in order to equate to Mmo, or 2.04 Mach). But in very cold conditions, the aircraft still 'wanting' to accelerate, and the simple Max Op/Max Op Soft modes just could not cope with gentle pitch changes alone. The problem became even bigger during the cruise/climb when severe temperature shears occured, and routinely regular Mmo exceedences occured. Something had to be done, and something WAS done and how; enter Max Climb/Max Cruise. It was really a classic piece of design, where the aircraft would do the initial supersonic climb in Max Climb mode. This mode itself was relatively simple, in that it was more or less a Vmo -Vc hold mode. That meant that the difference at selection between indicated airspeed, Vc and Vmo would be maintained, with a vernier datum adjust to this being available. In practice this mode was selected pretty much at Vmo, so datum adjusting was not always required. Now comes the clever part; the autothrottle, this would operate in standy mode at this point, just waiting there doing nothing, with the throttles at maximum as before. So the aircraft would now climb as Vmo increased to 530 KTS, and then following a now constant Vmo of 530 KTS until the magic 'corner point' (51, 189' remember). Now all hell would break loose; the mode would automatically change to Max Cruise, the autothrottle would also be automaically selected to Mach Hold mode (initially datumed here to Mach 2) and the throttles would retard, attempting to hold this Mach 2 datum, and the autopilot is commands a 'fly up' signal, over a 20 second lag period to 600'/minute. Now comes an even cleverer (?) part; the autothrottle Mach Hold datum is gradually increased over a 100 second period towards Mach 2.02, and so in stable conditions the throttles would now gradually increase again until they once more reach the maximum limit. At this point, the autothrottles now come out of Mach Hold mode and back into the waiting in the wings standby mode. The autopilot would now cancel it's 600' fly up, demand, returning to a datum of Mach 2. There was a little more complexity built in also, where the difference between the 'commanded' and actual vertical speeds offset the autoplilot Mach 2 datum. This would apply whether the autothrottle had cut in (+600'/min demand) or with the throttles back at maximum (0'/minute demand. A positive climb error tweaked the cruise Mach up slightly, a negative error (eg. in a turn) the converse was true. The effect of all of this complexity was that the aircraft itself could 'scan' until it settled at a point where the throttles could be at maximum, and the speed between Mach 2 and 2.02. On the North Atlantic, with warmer ISA temperatures, there was usually just the initial routine with the autothrottle as you hit the corner point. However at lower lattitudes (eg. LHR BGI) there could be a few initial autothrottle intercepts before things settled down. This whole incredible routine completely took care of the insurmountable problem, a problem that was shown not only to be insurmountable, but was put to bed forever, by people like ChristiaanJ.
I hope that my explanation here does not sound too much like gibberish.
EXWOK
I think you've guessed right as far as my identity goes; it's great that it's not just Concorde pilots I can bore the socks off now
PS. I bet the ex-SEOs LOVED your comments
Dude
Last edited by M2dude; 25th Aug 2010 at 01:14 . Reason: missed out some info' (sorry)
27th Aug 2010, 21:15
permalink Post: 143
Thanks Brit312 and ChristiaanJ.
Living in Bristol we used to see her go over on the way in to LHR and on a quiet day with the wind in the right direction we could sometimes here a very faint version of the "BaBoom" that was in the linked video.
Such a shame that they didn't keep at least one in a relatively easier to restore to flight condition and send it on the air show circuits with the Vulcan. With the talk of analogue FBW and PFCUs it reminded me of some of the Vulcan controls that I have read about, was there much technology transfer from the Vulcan to Concorde in the design stage?
Living in Bristol we used to see her go over on the way in to LHR and on a quiet day with the wind in the right direction we could sometimes here a very faint version of the "BaBoom" that was in the linked video.
Such a shame that they didn't keep at least one in a relatively easier to restore to flight condition and send it on the air show circuits with the Vulcan. With the talk of analogue FBW and PFCUs it reminded me of some of the Vulcan controls that I have read about, was there much technology transfer from the Vulcan to Concorde in the design stage?
28th Aug 2010, 03:37
permalink Post: 149
SLF in the jump seat
I rode Concorde two or three times and what a ride it was!
On one occasion I had booked to travel BA 'J' class from Washington to Delhi on a regular business trip. Out of DCA to JFK they booked me on the 'Concorde shuttle' (a Dash 8 of US Airways, believe it or not) to connect with a 744 to LHR and another connection on to Delhi. At DCA check in the agent mumbled something about a catering problem out of JFK, but I took no particular notice. On arrival at Kennedy an agent with a name placard diverted me to the Concorde gate, a nice surprise indeed, even for a BA Gold Card holder.
On boarding Concorde, I gave my business card to the purser, asking that she pass it forward. A few minutes later as the door was closing she came back to pass along an invitation from the skipper to join them in the cockpit. During the short delay for start clearance, the captain briefed me on the Canarsie 31L departure I was about to watch from the jump seat behind. "3-2-1 GO" as the aircraft lept forward, V1/Vr/V2, 100', roll left 30 degrees to track towards Canarsie, 1' 30" (or something similar, some details are long forgotten now) power back for 500'/minute ROC to 3,000', then accelerate to 250K as the heading continued around for the outbound course and the ocean crossing. A true aerial ballet.
For the balance of the climb I plied the guys with questions and received courteous and detailed answers to every one, along with a 'freebie' - some hilarious repartee between the BALPA captain and the management F/O type, with occasional interjections by the Engineer. I stayed through the supersonic acceleration until I thought I'd worn out my welcome at cruise climb, returning to my seat in the mid cabin area for lunch. They invited me back for the descent and approach, which was very well appreciated.
On descent over the U.K. and passing through 10K' abeam Southampton, as I remember it we got a yellow 'Radiation' caution light (normally to warn of higher than normal levels of radiation in the tropoause from sun spot activity, I believe), which caused me to ask WTHWT? The slightly bored F/O said, as he cancelled the light, "Oh, its 'just' a nuclear power plant down there, we get this all the time"! (And for all these years I had swallowed the PR line from the nuclear industry that they were squeaky clean, unlike those of us in the aircraft manufacturing business??)
The approach and landing at LHR was fascinating to watch, without the frenetic activity of the departure. No flaps and no configuration change after gear down, virtually no flare, perhaps even a little nose down pitch as I observed (was that true??) the handling pilot just let it float into ground effect for a gentle touch down, snappily into reverse and heavy, but not maximum braking. It looked easy, of course.
The F/E was a key part of the entire operation and I find it hard to believe that a Concorde "B" would have eliminated his position, no matter how automated the systems might have become. The whole flight was very, very professionally handled with that air of apparent casualness that comes only from a very disciplined team operating at the peak of performance. A true joy to watch.
I guess I was just a minor part of the vaunted 'halo' effect that BA marketing always claimed for Concorde - its ability to pull additional traffic to its worldwide services in a very competitive business climate. But it sure worked for me! And all because of a catering misadventure, or was that just an excuse??
However, the thing that has always truly amazed me about Concorde is that this machine was created by two companies, two countries, with two languages, two systems of measure and two very different cultures in a period before the invention of Computer Aided Design and on-line communications! What a marvellous thing that mankind created. My hat off to you all.
Thank you, John, that was some flight!
TC
On one occasion I had booked to travel BA 'J' class from Washington to Delhi on a regular business trip. Out of DCA to JFK they booked me on the 'Concorde shuttle' (a Dash 8 of US Airways, believe it or not) to connect with a 744 to LHR and another connection on to Delhi. At DCA check in the agent mumbled something about a catering problem out of JFK, but I took no particular notice. On arrival at Kennedy an agent with a name placard diverted me to the Concorde gate, a nice surprise indeed, even for a BA Gold Card holder.
On boarding Concorde, I gave my business card to the purser, asking that she pass it forward. A few minutes later as the door was closing she came back to pass along an invitation from the skipper to join them in the cockpit. During the short delay for start clearance, the captain briefed me on the Canarsie 31L departure I was about to watch from the jump seat behind. "3-2-1 GO" as the aircraft lept forward, V1/Vr/V2, 100', roll left 30 degrees to track towards Canarsie, 1' 30" (or something similar, some details are long forgotten now) power back for 500'/minute ROC to 3,000', then accelerate to 250K as the heading continued around for the outbound course and the ocean crossing. A true aerial ballet.
For the balance of the climb I plied the guys with questions and received courteous and detailed answers to every one, along with a 'freebie' - some hilarious repartee between the BALPA captain and the management F/O type, with occasional interjections by the Engineer. I stayed through the supersonic acceleration until I thought I'd worn out my welcome at cruise climb, returning to my seat in the mid cabin area for lunch. They invited me back for the descent and approach, which was very well appreciated.
On descent over the U.K. and passing through 10K' abeam Southampton, as I remember it we got a yellow 'Radiation' caution light (normally to warn of higher than normal levels of radiation in the tropoause from sun spot activity, I believe), which caused me to ask WTHWT? The slightly bored F/O said, as he cancelled the light, "Oh, its 'just' a nuclear power plant down there, we get this all the time"! (And for all these years I had swallowed the PR line from the nuclear industry that they were squeaky clean, unlike those of us in the aircraft manufacturing business??)
The approach and landing at LHR was fascinating to watch, without the frenetic activity of the departure. No flaps and no configuration change after gear down, virtually no flare, perhaps even a little nose down pitch as I observed (was that true??) the handling pilot just let it float into ground effect for a gentle touch down, snappily into reverse and heavy, but not maximum braking. It looked easy, of course.
The F/E was a key part of the entire operation and I find it hard to believe that a Concorde "B" would have eliminated his position, no matter how automated the systems might have become. The whole flight was very, very professionally handled with that air of apparent casualness that comes only from a very disciplined team operating at the peak of performance. A true joy to watch.
I guess I was just a minor part of the vaunted 'halo' effect that BA marketing always claimed for Concorde - its ability to pull additional traffic to its worldwide services in a very competitive business climate. But it sure worked for me! And all because of a catering misadventure, or was that just an excuse??
However, the thing that has always truly amazed me about Concorde is that this machine was created by two companies, two countries, with two languages, two systems of measure and two very different cultures in a period before the invention of Computer Aided Design and on-line communications! What a marvellous thing that mankind created. My hat off to you all.
Thank you, John, that was some flight!
TC
Last edited by twochai; 28th Aug 2010 at 04:05 .
2nd Sep 2010, 19:44
permalink Post: 191
Hydraulic failures
I had the pleasure of one trip as SLF on Concorde LHR - JFK (1978/9? grey cells depleting) which involved a return to LHR after dumping fuel due to hydraulic failure of two systems. No complaints from me, two take offs and landings for the price of one plus two hours of additional catering at LHR while the aircraft was fixed. Big run on asprins by the time we approached JFK!
However on the second departure the AC also suffered loss of hydraulic systems and I understood that it arrived at JFK on one system. After a storm delay at JFK I departed on AA listening to the ATC on the IFE with the Concorde following. Yet again the Concorde requested fuel dump and return due to hydraulic failures. The previous days I believe the Concorde had also experienced hydraulic failures and at one point BA cancelled some flights. AF were not experiencing the same problems and I read several years later that the problem was attributed to minute quantities of water being introduced into the system by a repenishing tanker being parked outside, wheras AF stored their tanker inside. The water then generated steam when the system ran with consequent seal failures.
Is the above cause correct, or was there more to the story?
Apart from all the normal Concorde observations, I also noticed that when trolling around over Bristol dumping fuel at a relatively high AoA the rear outboard surfaces, I was seated at the rear, vibrated at an alarming aplititude and frequency. Would this be caused by aerodynamic buffet or rapid auto pilot control inputs?
Thanks in anticipation.
However on the second departure the AC also suffered loss of hydraulic systems and I understood that it arrived at JFK on one system. After a storm delay at JFK I departed on AA listening to the ATC on the IFE with the Concorde following. Yet again the Concorde requested fuel dump and return due to hydraulic failures. The previous days I believe the Concorde had also experienced hydraulic failures and at one point BA cancelled some flights. AF were not experiencing the same problems and I read several years later that the problem was attributed to minute quantities of water being introduced into the system by a repenishing tanker being parked outside, wheras AF stored their tanker inside. The water then generated steam when the system ran with consequent seal failures.
Is the above cause correct, or was there more to the story?
Apart from all the normal Concorde observations, I also noticed that when trolling around over Bristol dumping fuel at a relatively high AoA the rear outboard surfaces, I was seated at the rear, vibrated at an alarming aplititude and frequency. Would this be caused by aerodynamic buffet or rapid auto pilot control inputs?
Thanks in anticipation.
2nd Sep 2010, 23:55
permalink Post: 192
Hi canuck slf, Your incident was not the hydraulic contamination one, I'll describe that one in a minute or so below.
As far as your adventure goes, in the early days of Concorde operation there was an on-going issue of hydraulic seal failures. This led to the sort of thing that you described, where a major seal failure would occur, resulting in the loss of a main system. The standby Yellow system would be switched in to replace the failed one, and depending on the nature of the initial failure, could leak out of the same failed seal. (There were a couple of 'common areas', they were the intake spill door jack, and the Powered Flying Control Units; failures here could result in a double system fail). Your incident was almost certainly due to one of these cases. In the early 1990's the original Neoprene hydraulic seals were replaced with a new Viton GLT seal; this material had far superior age shrinking characteristics to Neoprene, and more or less cured the problem overnight. Eventually all the seals in each aircraft were replaced, and apart from a very few isolated cases, dual system losses were eliminated forever. Air France suffered a similar proportion of failures, however as their flying hours were a fraction of BA's, the effects were not as immediately apparent.
As far as far as the hydraulic contamination story goes, this happened in 1980 but involved one aircraft only, G-BOAG, but in it's original registration of G-BFKW. (having previously been on loan from British Aerospace, where it flew originally as a 'white tail' under this registration). The fragile nature of Concorde hydraulic fluid was not fully understood at this time, and as you say, a hydraulic drum dispenser had inadvertently been left exposed to the atmosphere, and had subsequently suffered water contamination, and this contaminated fluid had found it's way into G-BOAG. Now this hydraulic fluid, CHEVRON M2V has only two vices: One is that is extremely expensive, and the second is that it is highly susceptible to water contamination, EXTEMELY SO. If my memory serves me correctly, the maximum allowable level of water in the fluid is about 8ppm. (parts per million) and the fluid that was analysed after G-BOAG's problems was at about 30 ppm. The water deposits in the fluid gave the equivalent effect of 'rusting up' of critical hydraulic components. I was investigating an air intake control defect the previous day to the incident, but like everybody else had no idea that the real issue here was one of major systems contamination. We were all convinced that we had nailed the problem, only to find that the aircraft turned back on it's subsequent LHR-JFK sector with more serious problems, not only affecting the air intakes, but the artificial feel system also. It was now that we realised that there had to be a hydraulics problem here, and after fluid analysis, the awful truth was discovered. After this event, and the fragilities of M2V fluid were better understood, a strict regime of housekeeping was put in place in terms of fluid storage, and no such incidents with BA ever occurring again. The aircraft itself did not fly again for nine months, all components that were affected were removed from the aircraft and completely stripped and overhauled. Also all of the system hydraulic lines had to be completely purged, until there were no further traces of any contamination. After the aircraft was finally rectified, she successfully again returned to service with her new 'BA' registration of G-BOAG. However the following year, during a C Check, it was decided that due to spares shortages, and the closure of the LHR-BAH-SIN route, there just was not being enough work for seven aircraft, and therefore G-BOAG would be withdrawn from service. (In terms of spares, BA at the time for instance only had six sets of aircraft galleys, as aircraft went in for C checks the galley was 'robbed' to service the aircraft coming out of it's own C check). The aircraft was parked in a remote hangar, and was only visited when a component had to be 'robbed' for another Concorde, and the aircraft soon fell into disrepair, was filthy externally and became a really sad sight. Many people (not myself I might add) were adamant that G-BOAG would never fly again. However, in 1984 things had really started to improve for Concorde, with the charter business increasing and the LHR-JFK route in particular becoming a staggering success. It was decided that OAG would be returned to an airworthy condition. In 1985, with a fresh new interior, and with the new BA colour scheme, she was finally returned to service; and remained as one of the mainstays of the fleet right up to the end of Concorde services in October 2003. She now resides at the Boeing Museum of Flight in Seattle. (I have particularly fond memories of G-BOAG; in a previous post I mentioned flying through an electrical storm in late 1991 over Saudi Arabia, while returning from BKK-BAH to LHR. What I forgot to mention was the spectacle of DOZENS of fierce fires burning on the ground, towards our starboard horizon. These were Sadams oil fires, still burning in Kuwait. It made a sombre contrast to the amazing electrical spectacle right in front of us).
As far as low speed flying control activity was concerned, this was a combination of the fairly flexible outer wing sections, being buffeted by low speed turbulence (the wing tip tanks 5A & 7A also being empty), as well as some autostab inputs. This was perfectly normal, and part of the design our aircraft. However the development aircraft had even more flexible outer wing sections, which used to almost straighten up in high speed flight. However due to fatigue concerns, external lateral stiffeners were added to the underside of the wings during production of the airline aircraft. (these can be easily seen from underneath the wings, just outboard of the nacelles). Unfortunately these external stiffeners also resulted in over a one tonne fuel penalty to the production aircraft, due to increased weight, as well as higher drag in a critical part of the wing aerodynamic surface.
Dude
As far as your adventure goes, in the early days of Concorde operation there was an on-going issue of hydraulic seal failures. This led to the sort of thing that you described, where a major seal failure would occur, resulting in the loss of a main system. The standby Yellow system would be switched in to replace the failed one, and depending on the nature of the initial failure, could leak out of the same failed seal. (There were a couple of 'common areas', they were the intake spill door jack, and the Powered Flying Control Units; failures here could result in a double system fail). Your incident was almost certainly due to one of these cases. In the early 1990's the original Neoprene hydraulic seals were replaced with a new Viton GLT seal; this material had far superior age shrinking characteristics to Neoprene, and more or less cured the problem overnight. Eventually all the seals in each aircraft were replaced, and apart from a very few isolated cases, dual system losses were eliminated forever. Air France suffered a similar proportion of failures, however as their flying hours were a fraction of BA's, the effects were not as immediately apparent.
As far as far as the hydraulic contamination story goes, this happened in 1980 but involved one aircraft only, G-BOAG, but in it's original registration of G-BFKW. (having previously been on loan from British Aerospace, where it flew originally as a 'white tail' under this registration). The fragile nature of Concorde hydraulic fluid was not fully understood at this time, and as you say, a hydraulic drum dispenser had inadvertently been left exposed to the atmosphere, and had subsequently suffered water contamination, and this contaminated fluid had found it's way into G-BOAG. Now this hydraulic fluid, CHEVRON M2V has only two vices: One is that is extremely expensive, and the second is that it is highly susceptible to water contamination, EXTEMELY SO. If my memory serves me correctly, the maximum allowable level of water in the fluid is about 8ppm. (parts per million) and the fluid that was analysed after G-BOAG's problems was at about 30 ppm. The water deposits in the fluid gave the equivalent effect of 'rusting up' of critical hydraulic components. I was investigating an air intake control defect the previous day to the incident, but like everybody else had no idea that the real issue here was one of major systems contamination. We were all convinced that we had nailed the problem, only to find that the aircraft turned back on it's subsequent LHR-JFK sector with more serious problems, not only affecting the air intakes, but the artificial feel system also. It was now that we realised that there had to be a hydraulics problem here, and after fluid analysis, the awful truth was discovered. After this event, and the fragilities of M2V fluid were better understood, a strict regime of housekeeping was put in place in terms of fluid storage, and no such incidents with BA ever occurring again. The aircraft itself did not fly again for nine months, all components that were affected were removed from the aircraft and completely stripped and overhauled. Also all of the system hydraulic lines had to be completely purged, until there were no further traces of any contamination. After the aircraft was finally rectified, she successfully again returned to service with her new 'BA' registration of G-BOAG. However the following year, during a C Check, it was decided that due to spares shortages, and the closure of the LHR-BAH-SIN route, there just was not being enough work for seven aircraft, and therefore G-BOAG would be withdrawn from service. (In terms of spares, BA at the time for instance only had six sets of aircraft galleys, as aircraft went in for C checks the galley was 'robbed' to service the aircraft coming out of it's own C check). The aircraft was parked in a remote hangar, and was only visited when a component had to be 'robbed' for another Concorde, and the aircraft soon fell into disrepair, was filthy externally and became a really sad sight. Many people (not myself I might add) were adamant that G-BOAG would never fly again. However, in 1984 things had really started to improve for Concorde, with the charter business increasing and the LHR-JFK route in particular becoming a staggering success. It was decided that OAG would be returned to an airworthy condition. In 1985, with a fresh new interior, and with the new BA colour scheme, she was finally returned to service; and remained as one of the mainstays of the fleet right up to the end of Concorde services in October 2003. She now resides at the Boeing Museum of Flight in Seattle. (I have particularly fond memories of G-BOAG; in a previous post I mentioned flying through an electrical storm in late 1991 over Saudi Arabia, while returning from BKK-BAH to LHR. What I forgot to mention was the spectacle of DOZENS of fierce fires burning on the ground, towards our starboard horizon. These were Sadams oil fires, still burning in Kuwait. It made a sombre contrast to the amazing electrical spectacle right in front of us).
As far as low speed flying control activity was concerned, this was a combination of the fairly flexible outer wing sections, being buffeted by low speed turbulence (the wing tip tanks 5A & 7A also being empty), as well as some autostab inputs. This was perfectly normal, and part of the design our aircraft. However the development aircraft had even more flexible outer wing sections, which used to almost straighten up in high speed flight. However due to fatigue concerns, external lateral stiffeners were added to the underside of the wings during production of the airline aircraft. (these can be easily seen from underneath the wings, just outboard of the nacelles). Unfortunately these external stiffeners also resulted in over a one tonne fuel penalty to the production aircraft, due to increased weight, as well as higher drag in a critical part of the wing aerodynamic surface.
Dude
Last edited by M2dude; 3rd Sep 2010 at 00:07 .
5th Sep 2010, 02:29
permalink Post: 215
It was certificated - up to a point. Problematic? Maybe not, but it was a part of the flt envelope to be treated with respect.
Obviously there are no spoilers, and once you translate to 'vortex lift' (stalled in conventional terms) there is definitely no shortage of drag. (This happened at about 250kts at landing weight).
Supersonic - it was certainly no sailplane and an ability to increase drag wasn't required.
So - there is a bit of the flight envelope where you are subsonic, descending at about 350kts IAS, where you may need a bit of drag; e.g. to make the FL140 limit on the OCK 1A SID (as it then was) to LHR.
To facilitate this, engines 2 and 3 could be selected to reverse idle within certain strict limitations (most of which have now left my brain). The mechanism was to ask the SFE to arm the system on his panel and then to select reverse on the inboards. Where the system was slightly unreliable was that you were running the air-driven buckets with the engines at idle thrust - consequently they sometimes didn't make a full reverse selection, in which case you canx reverse on that engine and managed on one.
Clearly the big event would be if they didn't translate into fwd thrust, which is one of the reasons it wasn't done below 10 000'. I'm not aware of this happening.
To be honest it was only really used when ATC threw an alt constraint at you during the descent, because in general if you just pitched down to 380kts (Vmo when subsonic at typical approach weights) you would get the height off comfortably.
Obviously there are no spoilers, and once you translate to 'vortex lift' (stalled in conventional terms) there is definitely no shortage of drag. (This happened at about 250kts at landing weight).
Supersonic - it was certainly no sailplane and an ability to increase drag wasn't required.
So - there is a bit of the flight envelope where you are subsonic, descending at about 350kts IAS, where you may need a bit of drag; e.g. to make the FL140 limit on the OCK 1A SID (as it then was) to LHR.
To facilitate this, engines 2 and 3 could be selected to reverse idle within certain strict limitations (most of which have now left my brain). The mechanism was to ask the SFE to arm the system on his panel and then to select reverse on the inboards. Where the system was slightly unreliable was that you were running the air-driven buckets with the engines at idle thrust - consequently they sometimes didn't make a full reverse selection, in which case you canx reverse on that engine and managed on one.
Clearly the big event would be if they didn't translate into fwd thrust, which is one of the reasons it wasn't done below 10 000'. I'm not aware of this happening.
To be honest it was only really used when ATC threw an alt constraint at you during the descent, because in general if you just pitched down to 380kts (Vmo when subsonic at typical approach weights) you would get the height off comfortably.
8th Sep 2010, 06:52
permalink Post: 268
As per a previous post of mine, I've uploaded a takeoff and landing from JFK - LHR, including the very minor blip on roll from JFK and the 1990mph on the Marilake.
YouTube - uvs040403 002 3
YouTube - uvs040403 002 3
9th Sep 2010, 08:29
permalink Post: 291
What a fascinating read, thanks to all guys contributing to it.
The fact that the Conc still fascinates so many people after so many years is the best prove of its uniqueness. Never flown on one, but having brought clients to it I remember a time where we parked right under the nose of an AF example at CDG with our tiny Cheyenne. The Pax was lead from our airplane up the stairs and off they went. (1989ish, I was a wet as a fish F/O then) Queing in Heathrow a few years later I couldn't hear my KingAirs engines for quite a while when the guys opened up and fired the cans. Fond memories and still the most graceful airplane I saw in my life.
I still use the opportunity to see the 2 examples at the museum at Le Bourget when there. Having seen a documentary on the first flights in Toulouse and Filton I had a trip to Filton a few days later and sitting in the air field ops Landrover was sort of a time travel.
We had the pleasure to have ex FE\xb4s and an ex Capt. as trainers at FlightSafety in Farnborough. Very nice blokes and I should add, very capable and knowledgable guys. One can see why they were on the sharp end.
Sorry that I cant ask a good question right now, just had to get my thanks off my chest!
The fact that the Conc still fascinates so many people after so many years is the best prove of its uniqueness. Never flown on one, but having brought clients to it I remember a time where we parked right under the nose of an AF example at CDG with our tiny Cheyenne. The Pax was lead from our airplane up the stairs and off they went. (1989ish, I was a wet as a fish F/O then) Queing in Heathrow a few years later I couldn't hear my KingAirs engines for quite a while when the guys opened up and fired the cans. Fond memories and still the most graceful airplane I saw in my life.
I still use the opportunity to see the 2 examples at the museum at Le Bourget when there. Having seen a documentary on the first flights in Toulouse and Filton I had a trip to Filton a few days later and sitting in the air field ops Landrover was sort of a time travel.
We had the pleasure to have ex FE\xb4s and an ex Capt. as trainers at FlightSafety in Farnborough. Very nice blokes and I should add, very capable and knowledgable guys. One can see why they were on the sharp end.
Sorry that I cant ask a good question right now, just had to get my thanks off my chest!
9th Sep 2010, 17:52
permalink Post: 301
M2D
A B747-400 at max take off weight (398tonnes) ex LHR would typically have a V1 ~ 155 kts, a Vr of about 170 and a V2 of 182 kts, so not dissimilar V1 speeds, but very different Vr and V2.
[I should add that this figures are for using reduced thrust and about 1.6 EPR on the RB211-524G engines where max thrust is about 1.72 EPR. Full thrust may result in an increased V1, I would guess].
This would suggest similar braking capabilities bearing in mind the differing TOWs involved. As to the relative brake unit weights I couldn't comment, nor therefore on the relative design pros and cons.
Numbers offered purely in response to your request.
A B747-400 at max take off weight (398tonnes) ex LHR would typically have a V1 ~ 155 kts, a Vr of about 170 and a V2 of 182 kts, so not dissimilar V1 speeds, but very different Vr and V2.
[I should add that this figures are for using reduced thrust and about 1.6 EPR on the RB211-524G engines where max thrust is about 1.72 EPR. Full thrust may result in an increased V1, I would guess].
This would suggest similar braking capabilities bearing in mind the differing TOWs involved. As to the relative brake unit weights I couldn't comment, nor therefore on the relative design pros and cons.
Numbers offered purely in response to your request.
12th Sep 2010, 08:57
permalink Post: 326
Hi again Stilton. We really need one of the flying folk to answer this one fully, I am not sure what drill there was for this scenario, but I'm sure there was one. The Concorde flying manual had a drill for everything, from a four engine flame out at Mach 2 to a blocked toilet (ok, maybe not the loo thing ), and one of my winged friends EXWOK, Bellerophon,
SEO
Brit312 would remember one.
As far as your point about moving the CG further aft; you never had oodles of fuel to play with , and I'm sure that the guys will mention about handling the aircraft on approach with the CG too far aft. (After landing four tonnes of fuel were transferred from Tanks 5 & 7 into the empty fwd Trim Tank 9, 'to aid ground stability'. ie, help stop the aircraft from trying to sit on it's rear end as the passengers got off).
As far as your visor query goes, well the visor is either up, or retracted into the nose. The nose itself (which I suspect is what you are really referring to) would already be at the fully down 12 1/2 degree setting for landing anyway.
Oh, and back to the ground stability issue, was Concorde ever sat on it's tail by accident? Oh yes, just once to my knowledge. In May 1977, aircraft G-BOAA was returned to Filton for some modifications that were required, and part of these 'mods' was some improvements to the main trim-transfer pipes connecting the three trim transfer tanks 9, 10 & 11, as well as the trim tanks 5 & 7. Now the flow into tank 11 (the rear tank) had to be checked, but there was insufficient fuel at the front of the aircraft for stability. This shortcoming was passed on to the BAe manager in charge of everything, who stuffily refused to listen, and INSISTED that these transfer checks were carried out, 'do as I tell you, I am the manager here'. The man's sole concession to any sort of common sense was to allow a BAe employee to sit on the flight deck 'and watch the CG indicator', what the point of this was, well your guess is as good as mine. The name of the guy sitting on the flight deck was... John Thomas. (Hilarious I know, but true). So in goes the fuel, and in a very short period of time, John Thomas notices that the roof of the Filton assembly hangar seems to be slowly getting closer, and closer, and BANG!! The aircraft nose is high into the roof section of the hangar, but fortunately because the hangar is so huge, the nose did not hit anything, it was just stuck up there, complete with a very worried/terrified John Thomas who is sitting terrified in the captain's seat, staring at the hangar roof. The rear of the aircraft however was not so lucky. The right hand inner elevon came down on top of a hydraulic rig, damaging the elevon badly, as well as FLATTENING the rig. The opened #3 engine bay door came down on some large access steps, tearing the corner of the door. (not much left of the steps either). The rear fuselage, in the area of the hydraulic tanks, was holed quite badly by some access staging, entire spectacle coming to a very 'grinding' halt.
So now we have this Concorde G-BOAA, due to be returned to BA the following day, sat down on top of a lot of equipment, it's nose high in the air with a terrified John Thomas requiring a change of underwear.
(The brilliant manager of course was nowhere to be seen). The aircraft was eventually returned to it's rightful attitude by someone WITH some sense instructing Mr Thomas on how to slowly, a little at a time, pump the fuel from Tank 11 forward into Tank 9.
And was OAA returned to BA the following day? errr no. The best skin repair man that BAe had to offer was sent from Weybridge to sort out the holes in the rear fuselage (he did an amazing job) and the crunched bits of aeroplane were repaired or replaced. OAA flew back to Heathrow four short (??) days later.
Dude
As far as your point about moving the CG further aft; you never had oodles of fuel to play with , and I'm sure that the guys will mention about handling the aircraft on approach with the CG too far aft. (After landing four tonnes of fuel were transferred from Tanks 5 & 7 into the empty fwd Trim Tank 9, 'to aid ground stability'. ie, help stop the aircraft from trying to sit on it's rear end as the passengers got off).
As far as your visor query goes, well the visor is either up, or retracted into the nose. The nose itself (which I suspect is what you are really referring to) would already be at the fully down 12 1/2 degree setting for landing anyway.
Oh, and back to the ground stability issue, was Concorde ever sat on it's tail by accident? Oh yes, just once to my knowledge. In May 1977, aircraft G-BOAA was returned to Filton for some modifications that were required, and part of these 'mods' was some improvements to the main trim-transfer pipes connecting the three trim transfer tanks 9, 10 & 11, as well as the trim tanks 5 & 7. Now the flow into tank 11 (the rear tank) had to be checked, but there was insufficient fuel at the front of the aircraft for stability. This shortcoming was passed on to the BAe manager in charge of everything, who stuffily refused to listen, and INSISTED that these transfer checks were carried out, 'do as I tell you, I am the manager here'. The man's sole concession to any sort of common sense was to allow a BAe employee to sit on the flight deck 'and watch the CG indicator', what the point of this was, well your guess is as good as mine. The name of the guy sitting on the flight deck was... John Thomas. (Hilarious I know, but true). So in goes the fuel, and in a very short period of time, John Thomas notices that the roof of the Filton assembly hangar seems to be slowly getting closer, and closer, and BANG!! The aircraft nose is high into the roof section of the hangar, but fortunately because the hangar is so huge, the nose did not hit anything, it was just stuck up there, complete with a very worried/terrified John Thomas who is sitting terrified in the captain's seat, staring at the hangar roof. The rear of the aircraft however was not so lucky. The right hand inner elevon came down on top of a hydraulic rig, damaging the elevon badly, as well as FLATTENING the rig. The opened #3 engine bay door came down on some large access steps, tearing the corner of the door. (not much left of the steps either). The rear fuselage, in the area of the hydraulic tanks, was holed quite badly by some access staging, entire spectacle coming to a very 'grinding' halt.
So now we have this Concorde G-BOAA, due to be returned to BA the following day, sat down on top of a lot of equipment, it's nose high in the air with a terrified John Thomas requiring a change of underwear.
(The brilliant manager of course was nowhere to be seen). The aircraft was eventually returned to it's rightful attitude by someone WITH some sense instructing Mr Thomas on how to slowly, a little at a time, pump the fuel from Tank 11 forward into Tank 9.
And was OAA returned to BA the following day? errr no. The best skin repair man that BAe had to offer was sent from Weybridge to sort out the holes in the rear fuselage (he did an amazing job) and the crunched bits of aeroplane were repaired or replaced. OAA flew back to Heathrow four short (??) days later.
Dude
14th Sep 2010, 10:49
permalink Post: 350
Blue concorde
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Yes, so my not-so-trivial questions, aimed more for F/E and Ground Engineers are:
1) with the same quantity on tanks 6 and 8, for example, 10 tons, there would be a roll tendency? I suspect yes, but not sure.
2) Using valves 6/7 and 5/8 would make lateral unbalance gone or they just leveled the fuel height on each pair of tanks? (Assuming that all these 4 tanks had the same height, what sounds logical to me)
3) Is there any table with these tanks quantities to reach lateral balance or the F/E did fine tune just by making elevons level?
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In answer to your questions , unlike the chart for C of G purposes there was no such chart for lateral trim rreasons. We would just transfer fuel across the ship so as to keep the elevons level at between 0 and 1 degree down. However when transfering fuel across the ship as the paired tanks are fore and aft of the C of G then when getting lateral trim you also affect the
C of G.
It is along time ago now and I cannot recall actual figures but your suggestion of between 500 and 700 kgs is I think a good ball park figure
The interconnect valves were never used under normal circumstances, but give it a go it might just over come your problem.
Nick Thomas
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remember that around 1980 one Concorde was painted on one side in the Singapore livery. Obviously the flight to Singapore would need at least one fuel stop. What I have always wondered is which part of the route was flown supersonic? Was she granted any overland supersonic rights? Also was it feasible to have a short supersonic section followed by a subsonic bit and then back to supersonic? I guess that having to use reheat to accelerate
twice to mach 2 would use too much fuel.
It was actually G-BOAD that was 1/2 painted in Singapore Airlines colours in the last part of !977
For more info on this subject check out this web site
CONCORDE SST : Singapore Concorde Services
The original route LHR- Bahrain flew subsonic across Europe and then accelerated to supersonic just off the coast in the north of the Adriatric. It was Supersonic then all the way to Bahrain avoiding islands in the Med but crossing the coast of the Lebenon still at supersonic speeds. This sector even with the long subsonic period [0.95 Mach] still cut the journey time LHR to BAH by 2.5 hours. For the crews the return trip to LHR was more exciting as once the throttles were opened to full power their position never changed until TOD. Once airbourne ---- reheat off at----------------- 500 ft
climb rating[switches] at----1000ft
climb/accel at 0.95r/heats back on and
away you go
The Bahrain - Singapore sector were my favourite though with only a short delay after Take Off before being cleared supersonic and because of the cold air temps at 50000ft plus the old girl would go up to 60,000ft and cruise there at Mach 2.0 and we would roar just south of Sri Lanka north of Indonesia and down the Malacca Straits slowing down and trying to avoid all the thunder heads
Although nothing actually to stop accelerating twice in a sector the fuel use on a long trip would usually not make this viable
NOTE How do you get the posh blue quote inserts
-------------------------------------------------------------------------
Yes, so my not-so-trivial questions, aimed more for F/E and Ground Engineers are:
1) with the same quantity on tanks 6 and 8, for example, 10 tons, there would be a roll tendency? I suspect yes, but not sure.
2) Using valves 6/7 and 5/8 would make lateral unbalance gone or they just leveled the fuel height on each pair of tanks? (Assuming that all these 4 tanks had the same height, what sounds logical to me)
3) Is there any table with these tanks quantities to reach lateral balance or the F/E did fine tune just by making elevons level?
----------------------------------------------------------------------------
In answer to your questions , unlike the chart for C of G purposes there was no such chart for lateral trim rreasons. We would just transfer fuel across the ship so as to keep the elevons level at between 0 and 1 degree down. However when transfering fuel across the ship as the paired tanks are fore and aft of the C of G then when getting lateral trim you also affect the
C of G.
It is along time ago now and I cannot recall actual figures but your suggestion of between 500 and 700 kgs is I think a good ball park figure
The interconnect valves were never used under normal circumstances, but give it a go it might just over come your problem.
Nick Thomas
---------------------------------------------------------------------
remember that around 1980 one Concorde was painted on one side in the Singapore livery. Obviously the flight to Singapore would need at least one fuel stop. What I have always wondered is which part of the route was flown supersonic? Was she granted any overland supersonic rights? Also was it feasible to have a short supersonic section followed by a subsonic bit and then back to supersonic? I guess that having to use reheat to accelerate
twice to mach 2 would use too much fuel.
It was actually G-BOAD that was 1/2 painted in Singapore Airlines colours in the last part of !977
For more info on this subject check out this web site
CONCORDE SST : Singapore Concorde Services
The original route LHR- Bahrain flew subsonic across Europe and then accelerated to supersonic just off the coast in the north of the Adriatric. It was Supersonic then all the way to Bahrain avoiding islands in the Med but crossing the coast of the Lebenon still at supersonic speeds. This sector even with the long subsonic period [0.95 Mach] still cut the journey time LHR to BAH by 2.5 hours. For the crews the return trip to LHR was more exciting as once the throttles were opened to full power their position never changed until TOD. Once airbourne ---- reheat off at----------------- 500 ft
climb rating[switches] at----1000ft
climb/accel at 0.95r/heats back on and
away you go
The Bahrain - Singapore sector were my favourite though with only a short delay after Take Off before being cleared supersonic and because of the cold air temps at 50000ft plus the old girl would go up to 60,000ft and cruise there at Mach 2.0 and we would roar just south of Sri Lanka north of Indonesia and down the Malacca Straits slowing down and trying to avoid all the thunder heads
Although nothing actually to stop accelerating twice in a sector the fuel use on a long trip would usually not make this viable
NOTE How do you get the posh blue quote inserts
14th Sep 2010, 16:32
permalink Post: 354
YOU are the best!
YOU have been and will
ALWAYS
remain the history, a mile stone in the aviation world!
Thank you, merc\xed, danke, grazie, gracias for sharing with us your experiences on this beauty! I have never read a more interersting thread since when i read PPRuNe!
I wish it would be possible to live again those days, in which aviation was a REAL special issue sorrounded by magic!
Without being too much nostalgic again i want to deeply thank all of you sharing with us the magic of the supersonic lady!
Just one qst. Thanks to her extremely high speed Concorde was able to fly to JFK from LHR in just 3hrs and 30mins. Usually this is a normal flight from LIRF to UUDD where the flight crew, offcourse, flies as well the way back. The flight crew of concorde used to fly from LHR to JFK and then back as well or they were finishing their duty period in JFK and another crew was taking over them?
Thanks again guys!
Thank you, merc\xed, danke, grazie, gracias for sharing with us your experiences on this beauty! I have never read a more interersting thread since when i read PPRuNe!
I wish it would be possible to live again those days, in which aviation was a REAL special issue sorrounded by magic!
Without being too much nostalgic again i want to deeply thank all of you sharing with us the magic of the supersonic lady!
Just one qst. Thanks to her extremely high speed Concorde was able to fly to JFK from LHR in just 3hrs and 30mins. Usually this is a normal flight from LIRF to UUDD where the flight crew, offcourse, flies as well the way back. The flight crew of concorde used to fly from LHR to JFK and then back as well or they were finishing their duty period in JFK and another crew was taking over them?
Thanks again guys!
14th Sep 2010, 18:20
permalink Post: 357
Galaxy flyer
Absolutely correct the T-heads often went up past us at 60000ft, which is quite scarey when you think of the energy required to do that. Makes you as part of mankind seem somewhat insignificant.
Avoiding them as another problemas the Malacca Straits is quite narrow, well it is for Concorde trying hard not to boom the land on either side, but as I remember it there were two good points
The T-storms seemed to be normally over the land either side, but more important we would start to slow down shortly after entering the Malacca Straits and once subsonic we were in the same ball park as other aircraft , avoid them at all cost, and we could then fly over land without upsetting people
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bio161
No the crews flew just the one trans Atlantic sector and then got off for a rest. Well you could not have us boys working too hard now .
In fact it was just possible for the crews to do a return trip and indeed when there were crew problems this was indeed done.
Morning flight
The Concorde report time was 1.5 before departure and a turn around at JFK would have been about 1.5 hours so when all added up it could have just been done. However any delay to either service could result in the home bound flight being late or indeed cancelled due to flight time limitations. This the company deemed to be unacceptable risk on an aircraft which was sold as saving time.
In fact as the morning flight was on approach to JFK,the morning flight back to LHR was already taking off. For the crew to now wait for the late departure back to London would put them way over FTLimitations
That did not mean the crews only did one sector a day
LHR-IAD-MIA was a days work as was the return.
On some of the charter flights it was often a multi sector day such as
Sydney--Brisbane --Guam --Beijing
I was only doing the PR on that trip so I have not got the times but it did seem a long day's work
Absolutely correct the T-heads often went up past us at 60000ft, which is quite scarey when you think of the energy required to do that. Makes you as part of mankind seem somewhat insignificant.
Avoiding them as another problemas the Malacca Straits is quite narrow, well it is for Concorde trying hard not to boom the land on either side, but as I remember it there were two good points
The T-storms seemed to be normally over the land either side, but more important we would start to slow down shortly after entering the Malacca Straits and once subsonic we were in the same ball park as other aircraft , avoid them at all cost, and we could then fly over land without upsetting people
--------------------------------------------------------------
bio161
Quote:
| Just one qst. Thanks to her extremely high speed Concorde was able to fly to JFK from LHR in just 3hrs and 30mins. Usually this is a normal flight from LIRF to UUDD where the flight crew, offcourse, flies as well the way back. The flight crew of concorde used to fly from LHR to JFK and then back as well or they were finishing their duty period in JFK and another crew was taking over them? |
In fact it was just possible for the crews to do a return trip and indeed when there were crew problems this was indeed done.
Morning flight
The Concorde report time was 1.5 before departure and a turn around at JFK would have been about 1.5 hours so when all added up it could have just been done. However any delay to either service could result in the home bound flight being late or indeed cancelled due to flight time limitations. This the company deemed to be unacceptable risk on an aircraft which was sold as saving time.
In fact as the morning flight was on approach to JFK,the morning flight back to LHR was already taking off. For the crew to now wait for the late departure back to London would put them way over FTLimitations
That did not mean the crews only did one sector a day
LHR-IAD-MIA was a days work as was the return.
On some of the charter flights it was often a multi sector day such as
Sydney--Brisbane --Guam --Beijing
I was only doing the PR on that trip so I have not got the times but it did seem a long day's work
14th Sep 2010, 18:30
permalink Post: 358
Also, regarding the practicalities of flying LHR-JFK-LHR, one has to remember that there were two airframes involved - the first return flight having nightstopped JFK. So the early JFK-LHR service was just taxying out as the morning LHR-JFK landed.
It was possible to operate the early JFK-LHR (BA002) and then turn round at LHR to operate the late LHR-JFK (BA003) and this was done occasionally, generally at short notice to cover illness or crew shortages.
I only did it once and you certainly knew you'd done it afterwards....
It was possible to operate the early JFK-LHR (BA002) and then turn round at LHR to operate the late LHR-JFK (BA003) and this was done occasionally, generally at short notice to cover illness or crew shortages.
I only did it once and you certainly knew you'd done it afterwards....
16th Sep 2010, 08:22
permalink Post: 369
I don't think you'll be finding hydrazine on a pax-carrying aircraft anytime soon! And it wasn't an APU as such, but a source of power for non-normals potentially found in the flight test programme. M2D and ChristiaanJwill know far more.
The charter flights were different insofar as they often went to non-BA stations, so there was a bit more donkeywork to be done to get all the paperwork organised, but nothing a regular charter pilot won't be used to. Generally one would get a fuel plan/flight plan filed from Ops at LHR, but apart from LHR/JFK/BGI/IAD (and presumably MIA/BAH/SIN in earlier days) we produced our own loadsheet. I only once had to produce a fuel plan/route plan from scratch and that was at Sondrestrom (as it was) with a dodgy fax line. You'd have to file a flight plan occasionally.
We carried a ' PR ' on most of them - a line pilot or FE - to carry out a running PA and do general liaison. They were volunteered to do the loadsheet.
The atmosphere on board was very different - these were pleasure flights and so were the opposite of the JFK business run. Landlady may be able to elaborate on this.
The round-the-worlds were just a big charter in this respect. As you note we carried a 'flying spanner', since Concorde-qualified LAEs are hard to come by downroute. It looked like a great job on paper, but they were often at the airport for many hours before or after the sectors carrying out routine maintenance or dealing with snags.
I enjoyed the charters a lot - everyone was geared up for a good time and in general the flight had something different for us, too: Whether a lightweight departure on a 'round-the-bay', squeezing into a short runway (e.g. Bournemouth), visiting SFJ or Rovaniemi, or setting off around the world, predominantly to non-BA destinations. My favourites, though, were the RTBs out of Filton - EVERYONE was either connected to Conc development or manufacture, or was related to someone who was. Fantastic atmosphere. Shame the runway wasn't a bit longer........
The charter flights were different insofar as they often went to non-BA stations, so there was a bit more donkeywork to be done to get all the paperwork organised, but nothing a regular charter pilot won't be used to. Generally one would get a fuel plan/flight plan filed from Ops at LHR, but apart from LHR/JFK/BGI/IAD (and presumably MIA/BAH/SIN in earlier days) we produced our own loadsheet. I only once had to produce a fuel plan/route plan from scratch and that was at Sondrestrom (as it was) with a dodgy fax line. You'd have to file a flight plan occasionally.
We carried a ' PR ' on most of them - a line pilot or FE - to carry out a running PA and do general liaison. They were volunteered to do the loadsheet.
The atmosphere on board was very different - these were pleasure flights and so were the opposite of the JFK business run. Landlady may be able to elaborate on this.
The round-the-worlds were just a big charter in this respect. As you note we carried a 'flying spanner', since Concorde-qualified LAEs are hard to come by downroute. It looked like a great job on paper, but they were often at the airport for many hours before or after the sectors carrying out routine maintenance or dealing with snags.
I enjoyed the charters a lot - everyone was geared up for a good time and in general the flight had something different for us, too: Whether a lightweight departure on a 'round-the-bay', squeezing into a short runway (e.g. Bournemouth), visiting SFJ or Rovaniemi, or setting off around the world, predominantly to non-BA destinations. My favourites, though, were the RTBs out of Filton - EVERYONE was either connected to Conc development or manufacture, or was related to someone who was. Fantastic atmosphere. Shame the runway wasn't a bit longer........