19th Aug 2010, 11:16
permalink Post: 25
Biggles78
Stupid, you? no way!! (Besides, I'm Mr Stupid of the aviation world, that's my title
). The thing is, out here in the world of flying machines, there are almost an infinite number of questions (and hopefully answers too). This applies to just about all aircraft from the Wright Flyer up!!.
Keep asking away, there are so many of us Concorde 'nuts' out here who are more than happy to help out/bore the socks off you.
Fuel burns: The problem was that when flying slow/taxying, Concorde was an extreme gas guzzler, even when idling each engine burnt around 1.1 tonnes/hour (so every 15 minutes after push back meant over a tonne gone). A typical taxi fuel would be around 1.4/1.5 tonnes, depending on the runway in use on the day. I'd have to leave it to some of my pilot/F/E friends to remember some of the specific fuel burns after take off etc, but I can at least give you some interesting consumption figures:
At the beginning of the take off roll, each engine would be burning around 21 tonnes/hour. (Made up of around 12 T/Hr dry fuel (Fe) and 9T/Hr afterburner (reheat to us Brits) fuel (Fr). As Fr was scheduled against Fe, as a function of inlet total temp (T1) by the time V2 was reached (around 220 KTS) the rising T1 has pushed the total fuel flow (Ft) up to a staggering 25 tonnes/hour/engine. As i've pointed out before in previous topics, although the afterburner only gave us a 17% improvement in take off thrust, it was responsible for around an 80% hike in fuel burn. (Hence that is whay it was only used sparingly). However when reheat was used for transonic acceleration, it used a dramatically reduced schedule (roughly a 60% rise in fuel flow) , so it was not quite as scary. The afterburner would be lit at the commencement of the acceleration (0.96 Mach) and cancelled completely at 1.7 Mach. After this time the aircraft would accelerate on dry power only up to mach 2 and beyond. (The cooler the temperature the quicker the time to Mach 2). On an ISA+ day, it sometimes felt that the aircraft was flying through cold porridge, and could take quite a while to get to Mach 2 after reaheat cancellation, where as on a nice ISA - day, she would go like a bat out of hell, and the AFCS would have to jump in to prevent overspeeds.
Before I hit some more numbers, let me say that with Concorde, TOC = TOD!! After reheat cancellation at Mach 1.7, the aircraft would be at FL 430. The aircraft would climb at an IAS of 530 KTS until Mach 2 was reached at fractionally over FL500. From then on the aircraft would cruise/climb as fuel was burnt, up to a maximum of FL600. On warmish days (eg. the North Atlantic) TOD would typically be around FL570-580. On a cool day (the lowes temperatures would of course be reached in the more tropical regions; the LGR-BGI sector encountered this), FL 600 would be reached easily and she would love to climb some more. BUT, the aircaft was only certificated to 60,000' with passengers onboard, for decompression emergency descent time reasons, and so we were stuck with it. The pity is of course, the fuel burn would have been improved, but we never were able to take advantage of this. On test flights however, the aircraft would routinely zoom climb to FL 630. On her maiden flight, aircaft 208 (G-BOAB) reached an altitude of 65000'; the highest recorded Concorde altitude was on one of the French development aircraft, which achieved 68,000'. On a technical point, the analog ADC's were 'only' calibrated to 65,000'.
Anyway, back to some figues; at Mach 2, 50,000', the typical fuel burn per engine would be around 5 tonnes/hour, falling to around 4.2 tonnes/hour at 60,000'.
THE NOSE You are quite correct in your assumption, there were two positions of droop: 5 deg's for taxi/take-off and low speed flight and 12.5 deg's for landing. The glazed visor retracted into the nose and could ONLY be raised once the nose was fully up, and had to be stowed before the nose could move down. There were 2 emergency nose lowering sysyems; one using stby (Yellow) hydraulics and a free-fall system. Free-fall would drop the nose all the way to 12.5 deg's, the visor free falling into the nose also.
Stupid, you? no way!! (Besides, I'm Mr Stupid of the aviation world, that's my title
). The thing is, out here in the world of flying machines, there are almost an infinite number of questions (and hopefully answers too). This applies to just about all aircraft from the Wright Flyer up!!.
Keep asking away, there are so many of us Concorde 'nuts' out here who are more than happy to help out/bore the socks off you.
Fuel burns: The problem was that when flying slow/taxying, Concorde was an extreme gas guzzler, even when idling each engine burnt around 1.1 tonnes/hour (so every 15 minutes after push back meant over a tonne gone). A typical taxi fuel would be around 1.4/1.5 tonnes, depending on the runway in use on the day. I'd have to leave it to some of my pilot/F/E friends to remember some of the specific fuel burns after take off etc, but I can at least give you some interesting consumption figures:
At the beginning of the take off roll, each engine would be burning around 21 tonnes/hour. (Made up of around 12 T/Hr dry fuel (Fe) and 9T/Hr afterburner (reheat to us Brits) fuel (Fr). As Fr was scheduled against Fe, as a function of inlet total temp (T1) by the time V2 was reached (around 220 KTS) the rising T1 has pushed the total fuel flow (Ft) up to a staggering 25 tonnes/hour/engine. As i've pointed out before in previous topics, although the afterburner only gave us a 17% improvement in take off thrust, it was responsible for around an 80% hike in fuel burn. (Hence that is whay it was only used sparingly). However when reheat was used for transonic acceleration, it used a dramatically reduced schedule (roughly a 60% rise in fuel flow) , so it was not quite as scary. The afterburner would be lit at the commencement of the acceleration (0.96 Mach) and cancelled completely at 1.7 Mach. After this time the aircraft would accelerate on dry power only up to mach 2 and beyond. (The cooler the temperature the quicker the time to Mach 2). On an ISA+ day, it sometimes felt that the aircraft was flying through cold porridge, and could take quite a while to get to Mach 2 after reaheat cancellation, where as on a nice ISA - day, she would go like a bat out of hell, and the AFCS would have to jump in to prevent overspeeds.
Before I hit some more numbers, let me say that with Concorde, TOC = TOD!! After reheat cancellation at Mach 1.7, the aircraft would be at FL 430. The aircraft would climb at an IAS of 530 KTS until Mach 2 was reached at fractionally over FL500. From then on the aircraft would cruise/climb as fuel was burnt, up to a maximum of FL600. On warmish days (eg. the North Atlantic) TOD would typically be around FL570-580. On a cool day (the lowes temperatures would of course be reached in the more tropical regions; the LGR-BGI sector encountered this), FL 600 would be reached easily and she would love to climb some more. BUT, the aircaft was only certificated to 60,000' with passengers onboard, for decompression emergency descent time reasons, and so we were stuck with it. The pity is of course, the fuel burn would have been improved, but we never were able to take advantage of this. On test flights however, the aircraft would routinely zoom climb to FL 630. On her maiden flight, aircaft 208 (G-BOAB) reached an altitude of 65000'; the highest recorded Concorde altitude was on one of the French development aircraft, which achieved 68,000'. On a technical point, the analog ADC's were 'only' calibrated to 65,000'.
Anyway, back to some figues; at Mach 2, 50,000', the typical fuel burn per engine would be around 5 tonnes/hour, falling to around 4.2 tonnes/hour at 60,000'.
THE NOSE You are quite correct in your assumption, there were two positions of droop: 5 deg's for taxi/take-off and low speed flight and 12.5 deg's for landing. The glazed visor retracted into the nose and could ONLY be raised once the nose was fully up, and had to be stowed before the nose could move down. There were 2 emergency nose lowering sysyems; one using stby (Yellow) hydraulics and a free-fall system. Free-fall would drop the nose all the way to 12.5 deg's, the visor free falling into the nose also.
Last edited by M2dude; 19th Aug 2010 at 12:40 . Reason: mistooks
19th Aug 2010, 13:21
permalink Post: 26
Mate, if you could have seen my jaw drop when I read the T/O burn you would probably hurt yourself laughing to much. That is just incredible but the cruise flow seems like stuff all especially considering the speed. The idle flow was also a bit of a jaw dropper.
Was surprised, yet again, that Mach 2 was achieved without reheat. They really were/are an amazing powerplant.
On my list of regrets, not getting a flight on Concorde would be in the top 5. If they hadn't grounded them what sort of life did the airframes have left in them?
Was surprised, yet again, that Mach 2 was achieved without reheat. They really were/are an amazing powerplant.
On my list of regrets, not getting a flight on Concorde would be in the top 5. If they hadn't grounded them what sort of life did the airframes have left in them?
20th Aug 2010, 12:06
permalink Post: 34
Biggles78
I know these fuel flows seem crazy (If take-off fuel flows had been maintained the endurance of the aircraft would have been about 55 minutes!!). But as the majority of the flight was carried out at Mach 2 and above, with the relatively miniscule fuel flows, you can see how we were able to cross the Atlantic with relative ease. It was the subsonic bit that was the pain.
The powerplant was as you say truly amazing. We had an, as yet, unmatched engine/intake combination, with a variable primary and secondary nozzles. The variable intake allowed supersonic operation with maximum pressure recovery, minimum aerodynamic drag, as well as extreme operational stability. (Extreme temperature shears, that would have caused surge/unstarts in military installations) were dealt with as a total non event). It's astonishing to believe, but at Mach 2 cruise, the intake provided approximately 63% of the powerplant thrust. It was controlled by the world's first airborne digital control system. (The system computers were built by the Guided Weapons Division of what was then BAC). The combination of the variable intake, plus the LP and HP compressors gave an overall compression ratio of 80:1.
The engine itself, being supplied with air at an ideal pressure, could run at an almost conststant TET, thanks to the variable primary nozzle. This also allowed N1 and N2 (corrected for total temperature) to be controlled more or less independently and run as close as possible to their separate surge lines throughout the entire flight envelope.
The variable secondary nozzle (wide open above Mach 1.1) allowed the jet efflux to gently expand against a cushion of air that was passed over the rear ramp of the intake, through the engine bay and into the annulus of the nozzle itself. This prevented thrust being wasted by the jet efflux widely splaying as it met ambient air that was at a pressure of as little as 1.04 PSIA.
It was this integrated powerplant that made true supersonic cruise possible
The airframe life issue was sort of like 'how long is a piece of string?'. The airframes are lifed in supersonic cycles, (which had been extended before, with modifications) and studies were always underway as far as further life extensions were concerned. (Basically the airframe was as tough as a brick outhouse in structural terms). The only real area of concern was the crown area (the roof
). There was a design flaw here in that the structure had not been designed fail-safe (allegedly by designed a Korean designer at A\xe9rospatiale who, it was said, went a bit loopy). When the FAA evaluated the design (in order for the aircraft to be registered in the USA, for Braniff operations out of IAD) they wanted 'crown planking' to be fitted externally, which would have added over a tonne to the weight of the aircraft, as well as producing some not inconsiderable drag. Fortunately a compromise was reached and additional NDT inspections were carried out, as well as more limited structural modifications. There was a long term, cost effective solution being studied, which would have cured the problem altogether. (The changes would have been mandated, over new requirements for ageing aircraft)
Nick Thomas
Nick, the whole expansion issue was one of the biggest issues that had to be addressed. Wiring looms would 'snake' in some underfllor areas to take up expansion, but the biggest difficulty of all were the mulitudes of hydraulic lines. These required sliding expansion joints, with of course seals to prevent leakage. When a seal deteriorated YPU GOT A LEAK!! (Fluid at 4000 PSI tends torun for freedom very quickly
). As far as fittings go, ChristiaanJ is quite right, you tried to anchor at one end only. I seem to remember that the passenger seat rails travelled over a roller afair. Fuel lines wer less of a problem, because their relative lengths were less.
I also agree wholeheartedly with ChristiaansJ's explanation about the 'friction' thing, I never really liked those stories. As a matter of interest, 127 deg's, for Mach 2, that would be at ISA +5 (-51.5 deg's C). Any warmer than that and we could not achieve Mach 2, due to the Tmo limit of 127. I remember one year, for several weeks we had unusually high north Atlantic temperatures; these impacted both the flight time AND the fuel burn. The further away you were from Mach 2, the higher the fuel consumption. (The faster you flew, the less fuel you burnt. How's that for a paradox?).
At ISA (-56.5 deg's C) temperatures, the total temperature was at around 118 deg's C.
ChristiaanJ
I remember the 17.5 degree position on the nose; it always looked as if the aircraft was trying to eat ants to me
. I can not recall personally anyone removing the 12.5 deg' stops for access, although this could of course have been done on your side of the 'puddle' I guess.
As far as the APU ducting issue goes (hee, hee, not often we disagree Christiaan
) we are just going to have to agree to disagee about this, although I accept that two 4" diameter pipes (PLUS THERMAL INSULATION) might have done it, BUT I still stand by the other points.
Stlton
Unfortunately not; the keel beam area was extremely thin and there was not anywhere near enough room. Interesting solution on the 727 though, I never knew that one.
Quote:
Mate, if you could have seen my jaw drop when I read the T/O burn you would probably hurt yourself laughing to much. That is just incredible but the cruise flow seems like stuff all especially considering the speed. The idle flow was also a bit of a jaw dropper.
|
Quote:
| Was surprised, yet again, that Mach 2 was achieved without reheat. They really were/are an amazing powerplant. |
The engine itself, being supplied with air at an ideal pressure, could run at an almost conststant TET, thanks to the variable primary nozzle. This also allowed N1 and N2 (corrected for total temperature) to be controlled more or less independently and run as close as possible to their separate surge lines throughout the entire flight envelope.
The variable secondary nozzle (wide open above Mach 1.1) allowed the jet efflux to gently expand against a cushion of air that was passed over the rear ramp of the intake, through the engine bay and into the annulus of the nozzle itself. This prevented thrust being wasted by the jet efflux widely splaying as it met ambient air that was at a pressure of as little as 1.04 PSIA.
It was this integrated powerplant that made true supersonic cruise possible
Quote:
| On my list of regrets, not getting a flight on Concorde would be in the top 5. If they hadn't grounded them what sort of life did the airframes have left in them? |
). There was a design flaw here in that the structure had not been designed fail-safe (allegedly by designed a Korean designer at A\xe9rospatiale who, it was said, went a bit loopy). When the FAA evaluated the design (in order for the aircraft to be registered in the USA, for Braniff operations out of IAD) they wanted 'crown planking' to be fitted externally, which would have added over a tonne to the weight of the aircraft, as well as producing some not inconsiderable drag. Fortunately a compromise was reached and additional NDT inspections were carried out, as well as more limited structural modifications. There was a long term, cost effective solution being studied, which would have cured the problem altogether. (The changes would have been mandated, over new requirements for ageing aircraft)
Nick Thomas
Nick, the whole expansion issue was one of the biggest issues that had to be addressed. Wiring looms would 'snake' in some underfllor areas to take up expansion, but the biggest difficulty of all were the mulitudes of hydraulic lines. These required sliding expansion joints, with of course seals to prevent leakage. When a seal deteriorated YPU GOT A LEAK!! (Fluid at 4000 PSI tends torun for freedom very quickly
). As far as fittings go, ChristiaanJ is quite right, you tried to anchor at one end only. I seem to remember that the passenger seat rails travelled over a roller afair. Fuel lines wer less of a problem, because their relative lengths were less.
I also agree wholeheartedly with ChristiaansJ's explanation about the 'friction' thing, I never really liked those stories. As a matter of interest, 127 deg's, for Mach 2, that would be at ISA +5 (-51.5 deg's C). Any warmer than that and we could not achieve Mach 2, due to the Tmo limit of 127. I remember one year, for several weeks we had unusually high north Atlantic temperatures; these impacted both the flight time AND the fuel burn. The further away you were from Mach 2, the higher the fuel consumption. (The faster you flew, the less fuel you burnt. How's that for a paradox?).
At ISA (-56.5 deg's C) temperatures, the total temperature was at around 118 deg's C.
ChristiaanJ
I remember the 17.5 degree position on the nose; it always looked as if the aircraft was trying to eat ants to me
. I can not recall personally anyone removing the 12.5 deg' stops for access, although this could of course have been done on your side of the 'puddle' I guess.
As far as the APU ducting issue goes (hee, hee, not often we disagree Christiaan
) we are just going to have to agree to disagee about this, although I accept that two 4" diameter pipes (PLUS THERMAL INSULATION) might have done it, BUT I still stand by the other points.
Stlton
Quote:
|
Not to beat a dead horse, but, on the choice of location for APU, the 727 had a problem with this but for different reasons. Because of the location of the engines that were all mounted at the rear, the Aircraft was quite tail heavy and adding more weight with an APU in the tail section was not desirable.The solution found that I have not seen in any other Aircraft was to mount it in the wheel well transversely across the keel beam with the exhaust out and over the right wing. Quite unusual but it worked fine with the restriction that it could only be operated on the ground.
Its all academic now but, just out of curiosity could this have worked on the Concorde |
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, 12:02
permalink Post: 90
MEMORIES
Like so many in the Concorde family, I have millions, I'd like to share a couple here. I remember at Fairford in mid 1974, a CAA test pilot (I honestly forget the gentleman's name) was taking the British pre-production A/C 101 (G-AXDN) for a special test flight. The reason that this flight was so special was that for the first time, the CAA were going to do an acceptance flight trial of the brand new digital air intake system. This revolutionary system had been retro fitted to 101 barely a year earlier, and being a brand new (and totally unique, in electronics terms) system had been plagued with teething troubles. It was quite reasonable for any airworthiness authority to have serious misgivings about any system that was going to wave great big metal lumps around in front of the engine compressor face, and that if only a few degrees out from the commanded position out could cause the engine to 'backfire' etc.
So anyway, 101 took off and disappeared into the very blue sky and we waited, and waited, AND WAITED. (I'd only left the RAF and joined the project a few months previously, and did not want my new association with this amazing aircraft to end). I was biting my nails, drinking coffee, losing my hair... (without the help of M2V
). Anyway after about 2 1/2 hours the aircraft returned to Fairford, and everybody crowds around the crew for the debrief. A very stern faced CAA pilot looked at us all, broke into a grin and said "as far as I'm concerned gentlemen, you've got yourselves an airliner". At that point the room was a study of total happiness, blessed relief, and a need to go to the loo..... But from my point of view, I will remember those words forever.
101, which now resides at the Imperial War Museum Duxford was the fastest Concorde ever. She achieved Mach 2.23, which was an incredible irony, as Concorde can trace a large part of it's developement history back to the BAC 223, proposed SST.
As far as flying memories go, I just don't know where to start; My first ever Concorde flight was in November 1976, out of Fairford on a pre-delivery test flight on G-BOAD. (Now sadly bobbing up and down on the Hudson, next to the USS Intrepid). I was staggered how fast and high we flew (Mach 2.08, FL580). Most of my flying up to that date had been in C-130's in the RAF, at around 340 KTS and FL300; Concorde also being infinately quiter in flight than the good old Herc'. I remember a BA QA guy showing me how I could touch the skin of the aircraft at Mach 2 (You reached behind a door busstle flap, moved your hand through some insulation until you felt bare metal). OUCH!! it was hot, very hot.
But I think one of my most memorable flight memories was aboard G-BOAG, (now residing in the Boeing Museum of Flight in Seattle) returning from BKK, having stopped off to refuel in BAH. We were forced to fly subsonic over Saudi, and got caught in this amazing electrical storm, There was St Elmo's fire cracking and bubbling all over the visor panels, but just as incredible was the long blue electrical discharge coming off of the nose probe; it seemed to extend about 50' in front of the aircraft. The crime was, none of us on the F/D had a camera. Every time I bump into the captain on that day (are you reading this Ian?), we go back to remonissing about that incredible flight. Also, later on the same sector, after we had decelerated to subsonic cruise again, this time flying up the Adriatic, we had another fascinating sight: It was getting quite dark now, and here we were, travelling at Mach 0.95 at FL290, when above us was all this Mach 0.8 ish traffic at around FL330-350. All we could see were all these navigation and ant-coll' lights above us, seemingly travelling backwards. It was quite a sight. On the original BAH-BKK sector a week earlier, we flew through some of the coldest air I'd ever seen; The air was at ISA -25, and at Mach 2 our TAT was only about 85 deg's C. (You could feel the difference too; the cabin windows felt only warm-ish to the touch). The upside also of all this was that your fuel burn was much lower than usual. (The only downside of course is that your TAS is a little lower). Rolls Royce did some analysis on the flight, and were amazed at how well the propulsion systems coped with some of the temperature sheers that we encountered, sometimes 4 to 5 deg's/second. They said that the prototype AFCS had been defeated by rises of only 0.25 deg's/second ).
Not meaning to go off onto a (yet another) tangent; Negative temperature shears, very common at lower lattidudes, always plagued the development aircraft; you would suddenly accelerate, and in the case of a severe shear, would accelerate and accelerate!! (Your Mach number, quite naturaly, suddenly increased with the falling temperature of course, but because of the powerplant suddenly hitting an area of hyper-efficiencey, the A/C would physically accelerate rapidly, way beyond Mmo). Many modifications were tried to mitigate the effects of severe shears, in the end a clever change to the intake control unit software fixed it. (Thanks to this change the production series A/C would not be capable of level flight Mach numbers of any more than Mach 2.13, remembering that Mmo was set at 2.04).
There was one lovely story, involving the Shah of Iran, having one of MANY flights in a developmment aircraft. The aircraft encounterd quite a hefty series of temperature shears that plagued havoc with some Iranian F4's that were attempting to close on the Concorde, to act as an escort for the Shah. (or so the strory goes). I'm still trying to picture these F4's, on full afterburner trying to get close to a Concorde cruising away on dry power). It is said that the F4's were having such difficulties, due to their relatively crude powerplant, coping with the temperature changes, that the Concorde was ordered to slow down, 'so the escorting F4's could catch up'!! True or not, it is part of Concorde folklore.
Dude
Like so many in the Concorde family, I have millions, I'd like to share a couple here. I remember at Fairford in mid 1974, a CAA test pilot (I honestly forget the gentleman's name) was taking the British pre-production A/C 101 (G-AXDN) for a special test flight. The reason that this flight was so special was that for the first time, the CAA were going to do an acceptance flight trial of the brand new digital air intake system. This revolutionary system had been retro fitted to 101 barely a year earlier, and being a brand new (and totally unique, in electronics terms) system had been plagued with teething troubles. It was quite reasonable for any airworthiness authority to have serious misgivings about any system that was going to wave great big metal lumps around in front of the engine compressor face, and that if only a few degrees out from the commanded position out could cause the engine to 'backfire' etc.
So anyway, 101 took off and disappeared into the very blue sky and we waited, and waited, AND WAITED. (I'd only left the RAF and joined the project a few months previously, and did not want my new association with this amazing aircraft to end). I was biting my nails, drinking coffee, losing my hair... (without the help of M2V
). Anyway after about 2 1/2 hours the aircraft returned to Fairford, and everybody crowds around the crew for the debrief. A very stern faced CAA pilot looked at us all, broke into a grin and said "as far as I'm concerned gentlemen, you've got yourselves an airliner". At that point the room was a study of total happiness, blessed relief, and a need to go to the loo..... But from my point of view, I will remember those words forever.
101, which now resides at the Imperial War Museum Duxford was the fastest Concorde ever. She achieved Mach 2.23, which was an incredible irony, as Concorde can trace a large part of it's developement history back to the BAC 223, proposed SST.
As far as flying memories go, I just don't know where to start; My first ever Concorde flight was in November 1976, out of Fairford on a pre-delivery test flight on G-BOAD. (Now sadly bobbing up and down on the Hudson, next to the USS Intrepid). I was staggered how fast and high we flew (Mach 2.08, FL580). Most of my flying up to that date had been in C-130's in the RAF, at around 340 KTS and FL300; Concorde also being infinately quiter in flight than the good old Herc'. I remember a BA QA guy showing me how I could touch the skin of the aircraft at Mach 2 (You reached behind a door busstle flap, moved your hand through some insulation until you felt bare metal). OUCH!! it was hot, very hot.
But I think one of my most memorable flight memories was aboard G-BOAG, (now residing in the Boeing Museum of Flight in Seattle) returning from BKK, having stopped off to refuel in BAH. We were forced to fly subsonic over Saudi, and got caught in this amazing electrical storm, There was St Elmo's fire cracking and bubbling all over the visor panels, but just as incredible was the long blue electrical discharge coming off of the nose probe; it seemed to extend about 50' in front of the aircraft. The crime was, none of us on the F/D had a camera. Every time I bump into the captain on that day (are you reading this Ian?), we go back to remonissing about that incredible flight. Also, later on the same sector, after we had decelerated to subsonic cruise again, this time flying up the Adriatic, we had another fascinating sight: It was getting quite dark now, and here we were, travelling at Mach 0.95 at FL290, when above us was all this Mach 0.8 ish traffic at around FL330-350. All we could see were all these navigation and ant-coll' lights above us, seemingly travelling backwards. It was quite a sight. On the original BAH-BKK sector a week earlier, we flew through some of the coldest air I'd ever seen; The air was at ISA -25, and at Mach 2 our TAT was only about 85 deg's C. (You could feel the difference too; the cabin windows felt only warm-ish to the touch). The upside also of all this was that your fuel burn was much lower than usual. (The only downside of course is that your TAS is a little lower). Rolls Royce did some analysis on the flight, and were amazed at how well the propulsion systems coped with some of the temperature sheers that we encountered, sometimes 4 to 5 deg's/second. They said that the prototype AFCS had been defeated by rises of only 0.25 deg's/second ).
Not meaning to go off onto a (yet another) tangent; Negative temperature shears, very common at lower lattidudes, always plagued the development aircraft; you would suddenly accelerate, and in the case of a severe shear, would accelerate and accelerate!! (Your Mach number, quite naturaly, suddenly increased with the falling temperature of course, but because of the powerplant suddenly hitting an area of hyper-efficiencey, the A/C would physically accelerate rapidly, way beyond Mmo). Many modifications were tried to mitigate the effects of severe shears, in the end a clever change to the intake control unit software fixed it. (Thanks to this change the production series A/C would not be capable of level flight Mach numbers of any more than Mach 2.13, remembering that Mmo was set at 2.04).
There was one lovely story, involving the Shah of Iran, having one of MANY flights in a developmment aircraft. The aircraft encounterd quite a hefty series of temperature shears that plagued havoc with some Iranian F4's that were attempting to close on the Concorde, to act as an escort for the Shah. (or so the strory goes). I'm still trying to picture these F4's, on full afterburner trying to get close to a Concorde cruising away on dry power). It is said that the F4's were having such difficulties, due to their relatively crude powerplant, coping with the temperature changes, that the Concorde was ordered to slow down, 'so the escorting F4's could catch up'!! True or not, it is part of Concorde folklore.
Dude
Last edited by M2dude; 24th Aug 2010 at 15:31 . Reason: spelling (again) :-(
24th Aug 2010, 14:59
permalink Post: 92
Fascinating thread. Please keep it going.
I see from photo in post 66 that pitch attitude at Mach 2 was about 4 nu. Could you say what attitudes were normal at other stages of flight?
I think I read that initial rotation was to a pre-computed attitude which allowed for simultaneous climb and acceleration. What was the speed typically when re-heat was cancelled at I assume 1000 agl?
Jo
I see from photo in post 66 that pitch attitude at Mach 2 was about 4 nu. Could you say what attitudes were normal at other stages of flight?
I think I read that initial rotation was to a pre-computed attitude which allowed for simultaneous climb and acceleration. What was the speed typically when re-heat was cancelled at I assume 1000 agl?
Jo
26th Aug 2010, 10:23
permalink Post: 128
take-off performance
Galaxy flyer -
TO perf calcs were basically sinilar to a susonic type, which involved a tabulation for each runway in a manual and an A4 proforma.
It was no more complex than a 'Classic' 747, but with a slightly different emphasis - e.g. all take-offs at full, reheated thrust, calculation of fuel transfer or burn off during taxy to achieve TOCG, calculation of timings and thrust setting for runway-specific noise abatement procedures, calculation of theta 2, and planned fuel flow and P7 to set in the take-off monitor (A system designed to aid, but not substitute, the decision of the FE as to whether TO thrust had been achieved, as well as auto selection of contingency power if a failure was detected).
You'd also determine whether a single reheat failure was acceptable that day - the little '3' or '4' bug at the lower left of the engine instruments was set as a visual reminder.
Not sure what you mean by Vzf? No flaps on this machine, so no change. May be a difference of nomenclature. Since there is no defined stalling speed for a delta (by conventional standards we lifted off about 60kts below 'stalling speed') Vzrc was substitued. This is the speed at which full thrust would result in a zero rate of climb. On three engines, this was the basis of the perf calculation, but we also calculated 2-eng Vzrc's gear up and gear down. IIRC they would come out at about 250kts/300kts.
On a transatlantic sector you would do all this and the speeds would invariably be within 5 kts of 160/190/220kts. (V1,Vr,V2)......
In the end we had a little handheld computer which would perform take off calcs, but to be honest it was only a minute more effort to carry out a manual calc.
TO perf calcs were basically sinilar to a susonic type, which involved a tabulation for each runway in a manual and an A4 proforma.
It was no more complex than a 'Classic' 747, but with a slightly different emphasis - e.g. all take-offs at full, reheated thrust, calculation of fuel transfer or burn off during taxy to achieve TOCG, calculation of timings and thrust setting for runway-specific noise abatement procedures, calculation of theta 2, and planned fuel flow and P7 to set in the take-off monitor (A system designed to aid, but not substitute, the decision of the FE as to whether TO thrust had been achieved, as well as auto selection of contingency power if a failure was detected).
You'd also determine whether a single reheat failure was acceptable that day - the little '3' or '4' bug at the lower left of the engine instruments was set as a visual reminder.
Not sure what you mean by Vzf? No flaps on this machine, so no change. May be a difference of nomenclature. Since there is no defined stalling speed for a delta (by conventional standards we lifted off about 60kts below 'stalling speed') Vzrc was substitued. This is the speed at which full thrust would result in a zero rate of climb. On three engines, this was the basis of the perf calculation, but we also calculated 2-eng Vzrc's gear up and gear down. IIRC they would come out at about 250kts/300kts.
On a transatlantic sector you would do all this and the speeds would invariably be within 5 kts of 160/190/220kts. (V1,Vr,V2)......
In the end we had a little handheld computer which would perform take off calcs, but to be honest it was only a minute more effort to carry out a manual calc.
26th Aug 2010, 13:55
permalink Post: 130
EXWOK
Excuse me, Vzrc was exactly what I meant. I remember reading it in the Concorde CDG report and wondered if it figured into daily per calcs or was it a more technical
If you could depart with 3 reheats, I guess it wasn't a problem with the transition to supersonic flight? What I find amazing is the F-22 goes on about super cruise but here was a plane designed over 40 years that routinely super cruised.
GF
Excuse me, Vzrc was exactly what I meant. I remember reading it in the Concorde CDG report and wondered if it figured into daily per calcs or was it a more technical
If you could depart with 3 reheats, I guess it wasn't a problem with the transition to supersonic flight? What I find amazing is the F-22 goes on about super cruise but here was a plane designed over 40 years that routinely super cruised.
GF
27th Aug 2010, 20:41
permalink Post: 142
notfred
,
Not exactly the same subject, but still brake-related.
Some of the earlier-mentioned items like "3-2-1-NOW", the little 3/4 tab for the afterburners, the "T/O monitor lights" and such, were all due to the fact that it was not possible to run up Concorde to full take-off thrust, light the reheats, check everything, and only then release the brakes.... she would start to slide forward well before full thrust was reached.
Only 185 tons TOW, only ten little wheels... in brief, not enough "grip" to keep almost 70 tons thrust stationary !
CJ
Not exactly the same subject, but still brake-related.
Some of the earlier-mentioned items like "3-2-1-NOW", the little 3/4 tab for the afterburners, the "T/O monitor lights" and such, were all due to the fact that it was not possible to run up Concorde to full take-off thrust, light the reheats, check everything, and only then release the brakes.... she would start to slide forward well before full thrust was reached.
Only 185 tons TOW, only ten little wheels... in brief, not enough "grip" to keep almost 70 tons thrust stationary !
CJ
27th Aug 2010, 21:32
permalink Post: 144
ChristiaanJ
The way I remember it was
"3-2-1 now" was to ensure that all 3 crew members started their stop watch at the same time i e on the call of NOW as that was the point the throttles were moved rapidy to the forward stops. In fact the noise abatement timing assumed the engines were allowed to accelerate at their own rate, rather than at a rate controlled by the crew
"Green lights" served two purposes
1] To allow the pilots to have a quick reference as to the state of the engines during the Take off
2] Prior to the nose gear mod ona rough runway [when it could be difficult to red the engine instruements] it did give the F/E an indication that the engines had reached the basic power required
3/4 tab. as different T/Os required diferent minimum reheats either 3 or 4
The small 3/4 tab was there just to visually remind crew as a back up to the briefing whether they were on a 3 or 4 reheat day
I have not I believe been on an aircraft where you run up to full power before releasing the brakes, but there again the memory could be fading, and I am sure the sudden release of brakes at full power would not do them any
good
Mind you I could be wrong
The way I remember it was
"3-2-1 now" was to ensure that all 3 crew members started their stop watch at the same time i e on the call of NOW as that was the point the throttles were moved rapidy to the forward stops. In fact the noise abatement timing assumed the engines were allowed to accelerate at their own rate, rather than at a rate controlled by the crew
"Green lights" served two purposes
1] To allow the pilots to have a quick reference as to the state of the engines during the Take off
2] Prior to the nose gear mod ona rough runway [when it could be difficult to red the engine instruements] it did give the F/E an indication that the engines had reached the basic power required
3/4 tab. as different T/Os required diferent minimum reheats either 3 or 4
The small 3/4 tab was there just to visually remind crew as a back up to the briefing whether they were on a 3 or 4 reheat day
I have not I believe been on an aircraft where you run up to full power before releasing the brakes, but there again the memory could be fading, and I am sure the sudden release of brakes at full power would not do them any
good
Mind you I could be wrong
27th Aug 2010, 22:25
permalink Post: 146
Brit312
Your memory is not fading; the ONLY disadvantage with carbon brakes is their susceptabilty to over-torque damage. For this reason 'max power on brakes wasalways verboten. I seem to remember that the development A/C with steel brakes could be 'wound up' on the brakes. But the improved braking performance, not to mention a 1,200lb weight saving of carbon made this a small price to pay.
The 3/4 tab; that takes me back, it was officially called the 'Reheat Capability Indicator', definately not the most sophisticated part of the Concorde flight deck. (I seem to remember that before the 'RCI
' was fitted, an INS CDU Waypoint thumbwheel was used as a 3 or 4 reminder).
Oh and ChristiaanJ; I always loved that clip.
Dude
Your memory is not fading; the ONLY disadvantage with carbon brakes is their susceptabilty to over-torque damage. For this reason 'max power on brakes wasalways verboten. I seem to remember that the development A/C with steel brakes could be 'wound up' on the brakes. But the improved braking performance, not to mention a 1,200lb weight saving of carbon made this a small price to pay.
The 3/4 tab; that takes me back, it was officially called the 'Reheat Capability Indicator', definately not the most sophisticated part of the Concorde flight deck. (I seem to remember that before the 'RCI
' was fitted, an INS CDU Waypoint thumbwheel was used as a 3 or 4 reminder).
Oh and ChristiaanJ; I always loved that clip.
Dude
31st Aug 2010, 00:01
permalink Post: 164
M2dude I have another question concerning "debow" You very clearly answered my original question on another thread. I just wondered how the engine was kept at a sub idle 30% N2? Was it done by careful metering of the fuel? and if not how was it done? I ask because the throttles would be closed during start up.
The whole engine installation with the ramps, spill doors, reheats and noozles must have been a nightmare to "fine tune" through all the different phases of flight.
Thanks for the explanation of how the pitch was "trimmed" Due to Concorde having elevrons instead of ailerons; was the aileron trim dealt with in a similar way? I guess the rudder trim could be applied normally.
Thanks again
Nick
The whole engine installation with the ramps, spill doors, reheats and noozles must have been a nightmare to "fine tune" through all the different phases of flight.
Thanks for the explanation of how the pitch was "trimmed" Due to Concorde having elevrons instead of ailerons; was the aileron trim dealt with in a similar way? I guess the rudder trim could be applied normally.
Thanks again
Nick
5th Sep 2010, 11:56
permalink Post: 217
In-Flight Reverse (A case of Bucket and See)
Capt Chambo
Concorde was, as EXWOK says, could use reverse in flight, on the inboard engines only, and only as far as reverse idle, the mechanism of which was quite complex and did on occasion not do work as advertised. Bear in mind here that the Rolls Royce Olympus 593 was a pure turbojet with no bypass, and so a hot stream reverser only had to be used; the reverser buckets acting directly on the efflux as it did any reverser in the 'old' days. Also the same buckets that were used for reverse were also progressively opened up between Mach 0.55 and wide open at Mach 1.1, this giving a vital control enhancement to the divergencing efflux. The overall effect of this was to give a true overall convergent/divergent nozzle assembly, the ideal for any supersonic aircraft.
As far as inflight reverse goes, the amount of HP compressor delivery air (P3) required to actuate the bucket airmotor in flight at an idle thrust settings, was quite minimal to say the least, and some help was definitely needed here. The moment that inflight reverse was selected (on the inboard engines only remember) the OUTBOARD engines would have their idle N2 automatically increased, and some of THEIR P3 air supply was also automatically ported over (via an isolation valve) to the inboard buckets. This whole process was required in order to give a little added muscle to the bucket airmotors, and give the system a fighting chance. Even this however was still not quite enough, the inboard travelling buckets required minimal air loading on their surface, and so the primary nozzles for the affected engines (the primary nozzle lived just aft of the LP turbine, aft of the reheat assembly) was automatically signalled wide open in order to assist matters here, by reducing gas velocity. One the buckets had reached full reverse the primary nozzle was then signalled full close (this applied for normal ground reverse also) and the automatic increased idle on the outboard engines was cancelled. To enable the described process to occur, provided all four engines were at idle, a solenoid latched button on the F/E's station could be selected. This signalled a circuit that enabled the selection of idle reverse on the inboard engines only, the opening of the P3 isolation valve, the raising of the outboard engine's idle and maximum primary nozzle angle for the outboards as soon as reverse was then selected..
The whole system was just a little fragile here; failure of either the extra air supply, or the raised idle on the 'other' engine was usually enough to stop the process working correctly.
EXWOK
While flying 'up front' I only ever experienced the use of inflight reverse once. (The captain was a bit of an Animal, if you flying guys see what I mean
). I would not say that it felt as if we'd hit a brick wall, as I'd expected the sensation to feel, more like we were flying into the dumped contents of a very large manure truck
. The whole operation was so slick, we'd dumped the required amount of IAS more or less within a second or two, and normal thrust was immediately selected. As so often happened with you guys, you made it look too easy.
As far as the speed of the airmotor goes, I seem to remember that it was something in the order of 80,000 RPM at max chat; as you say faster (around twice as fast) as the standby horizon motor.
The basic core airmotor (not the whole assembly) was the same Garrett unit used on the P&W JT9 as well as the RB-211.
Dude
Concorde was, as EXWOK says, could use reverse in flight, on the inboard engines only, and only as far as reverse idle, the mechanism of which was quite complex and did on occasion not do work as advertised. Bear in mind here that the Rolls Royce Olympus 593 was a pure turbojet with no bypass, and so a hot stream reverser only had to be used; the reverser buckets acting directly on the efflux as it did any reverser in the 'old' days. Also the same buckets that were used for reverse were also progressively opened up between Mach 0.55 and wide open at Mach 1.1, this giving a vital control enhancement to the divergencing efflux. The overall effect of this was to give a true overall convergent/divergent nozzle assembly, the ideal for any supersonic aircraft.
As far as inflight reverse goes, the amount of HP compressor delivery air (P3) required to actuate the bucket airmotor in flight at an idle thrust settings, was quite minimal to say the least, and some help was definitely needed here. The moment that inflight reverse was selected (on the inboard engines only remember) the OUTBOARD engines would have their idle N2 automatically increased, and some of THEIR P3 air supply was also automatically ported over (via an isolation valve) to the inboard buckets. This whole process was required in order to give a little added muscle to the bucket airmotors, and give the system a fighting chance. Even this however was still not quite enough, the inboard travelling buckets required minimal air loading on their surface, and so the primary nozzles for the affected engines (the primary nozzle lived just aft of the LP turbine, aft of the reheat assembly) was automatically signalled wide open in order to assist matters here, by reducing gas velocity. One the buckets had reached full reverse the primary nozzle was then signalled full close (this applied for normal ground reverse also) and the automatic increased idle on the outboard engines was cancelled. To enable the described process to occur, provided all four engines were at idle, a solenoid latched button on the F/E's station could be selected. This signalled a circuit that enabled the selection of idle reverse on the inboard engines only, the opening of the P3 isolation valve, the raising of the outboard engine's idle and maximum primary nozzle angle for the outboards as soon as reverse was then selected..
The whole system was just a little fragile here; failure of either the extra air supply, or the raised idle on the 'other' engine was usually enough to stop the process working correctly.
EXWOK
While flying 'up front' I only ever experienced the use of inflight reverse once. (The captain was a bit of an Animal, if you flying guys see what I mean
). I would not say that it felt as if we'd hit a brick wall, as I'd expected the sensation to feel, more like we were flying into the dumped contents of a very large manure truck
. The whole operation was so slick, we'd dumped the required amount of IAS more or less within a second or two, and normal thrust was immediately selected. As so often happened with you guys, you made it look too easy.
As far as the speed of the airmotor goes, I seem to remember that it was something in the order of 80,000 RPM at max chat; as you say faster (around twice as fast) as the standby horizon motor.
The basic core airmotor (not the whole assembly) was the same Garrett unit used on the P&W JT9 as well as the RB-211.
Dude
Last edited by M2dude; 5th Sep 2010 at 13:25 .
7th Sep 2010, 08:39
permalink Post: 250
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).
Yes ChristaanJ, I FINALLY managed to upload stuff here.
Yes ChristaanJ, I FINALLY managed to upload stuff here.
13th Sep 2010, 11:29
permalink Post: 339
EXWOK's superb post above really characterises what Concorde was all about; An aircraft with 100 Champagne sipping passengers sitting in total comfort, the aircraft sat at Mach 2 - 2.02, 60,000' and wanting really to both climb and accelerate, but having to be restrained to prevent this and the engines poodling along and nothing approaching their maximum power. Seven cabin crew happily looking after their one hundred charges and three VERY lucky guys, sat at the front of this wonderful aircraft in shirtsleeve comfort and having really the best time of anyone aboard.
ANY fighter of the time would have to have been on full afterburner with the pilot in a sweaty flying suit and bone dome and only able to stay at anything like this speed for a VERY few minutes.
To EXWOK and the other guys (and gal
) I take my hat off, because you made it happen. Because of all you guys BA had 27 years of highly successful and TOTALLY SAFE Concorde operation. In the VERY few times that things did not go to plan, your skill and professionalism made the hairiest of moments seem like total routine.
And stilton my friend, we are in debt to you for starting this thread in the first place. Keep asking away and we'll all do our best to give you as straight an answer as possible; it's really fun for us too.
ANY fighter of the time would have to have been on full afterburner with the pilot in a sweaty flying suit and bone dome and only able to stay at anything like this speed for a VERY few minutes.
To EXWOK and the other guys (and gal
) I take my hat off, because you made it happen. Because of all you guys BA had 27 years of highly successful and TOTALLY SAFE Concorde operation. In the VERY few times that things did not go to plan, your skill and professionalism made the hairiest of moments seem like total routine.
And stilton my friend, we are in debt to you for starting this thread in the first place. Keep asking away and we'll all do our best to give you as straight an answer as possible; it's really fun for us too.
Last edited by M2dude; 13th Sep 2010 at 12:26 .
13th Sep 2010, 20:35
permalink Post: 348
Hi again
I 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.
Thanks Landlady for your posts on Concorde. As SLF I never flew on her but thanks to you I now have an idea of what a wonderful experience it would have been.
Regards
Nick
I 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.
Thanks Landlady for your posts on Concorde. As SLF I never flew on her but thanks to you I now have an idea of what a wonderful experience it would have been.
Regards
Nick
14th Sep 2010, 10:49
permalink Post: 350
Blue concorde
-------------------------------------------------------------------------
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
-------------------------------------------------------------------------
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
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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
20th Sep 2010, 16:18
permalink Post: 424
Interesting & nostalgic thread. Nice to see this monumental aviation achievement still generates such passion...
In case it's of interest (and suitable health warning as the memory fades)...
The heat did evaporate water vapour in the airframe - reducing corrosion. I remember when the 5 BA aircraft were returned to service, after the post-accident mods, their weight and balance certificates were prepared and found to be out by (IIRC) more than a tonne. This represented water in the airframe present after a year on the ground, and was gone again after a couple hours of supercruise on return to service. Back to the weighbridge for new W&B Certificates....
Vortex lift caused buffet which felt very similar to a conventional wing's stall/low speed buffet. At landing weights (I hate the trend of using the term "mass": weight is a force, mass is not!) you felt the buffet start as you reduced speed (CAS: Vc) to about 250kts. It was handy as a reminder that you should select visor down / nose to five below 250kts (the recommendation was as you slowed through 270kts, but latterly we were in the habit of holding at 250kts nose/visor up - I think TCAS was quoted as a backup to the more limited visibility in that config). At takeoff weights, the buffet went at more like 270kts accelerating. So I'm pretty sure there was no vortex lift at AoA > 7 degrees (250kts at LW).
Recommended subsonic cruise at MTOW was F260 / M0.95 which was equal to Vmo of 400kts (CAS). It was best cruise because Vc=400kts was also min drag at MTOW. F280 meant a slightly more draggy speed of 384kts, but some preferred it because when cleared to climb & accelerate supersonic (the official expression was "go for it") it gave you a bit of slack against Vmo when eng put the reheats in. But we tended to ignore the overspeed warning anyway: it was supposed to go really really fast...
We never flew with visor down and nose up unless it was bust - that config was only used during pushback (except one captain who always thought it looked better visor up....). Visor down max Vc was 325kts/M0.8 so it would limit subsonic cruise, and besides it made a racket like that.
It was a beaut in x-winds - a total lack of yaw-roll couple meant you just straightened the 'plane up with rudder and carried on into the flare as normal. No roll to counteract, and the sideways "lift" created by the rudder deflection on the fin pretty much equalled the x-wind drift. Nice.
Wind limits were Crosswind 30kts (15kts contaminated or autoland), Headwind for autoland 25kts (or manual "reduced noise" approach: that's a technical way we used to reduce the noise footprint down to 800' by flying at 190kts then reducing to a target speed of Vref+7kts at that point). Tailwind 10kts. All these limits were, of course, subject to "on the day" performance limits calculated at the time. I seem to remember there was an over-arching limit of 6000' on r/w length, subject again to "on the day" performance limits. OK, I cheated on this paragraph and dug out FM Vol 2a.
There were loads of other limitations which were, by and large, more "esoteric" than a conventional airliner and which had to be learned for the conversion course. It really made the head hurt, and would have been impossible without a big loverrly picture of the beast on the wall chucking out yellow smoke and making noise. Even a static picture of her seemed to make noise...
No one who flew it could really believe their luck, but one thing for sure is "they don't build them like that any more"...
Ahhhhhhhhhhhhhh..........
In case it's of interest (and suitable health warning as the memory fades)...
The heat did evaporate water vapour in the airframe - reducing corrosion. I remember when the 5 BA aircraft were returned to service, after the post-accident mods, their weight and balance certificates were prepared and found to be out by (IIRC) more than a tonne. This represented water in the airframe present after a year on the ground, and was gone again after a couple hours of supercruise on return to service. Back to the weighbridge for new W&B Certificates....
Vortex lift caused buffet which felt very similar to a conventional wing's stall/low speed buffet. At landing weights (I hate the trend of using the term "mass": weight is a force, mass is not!) you felt the buffet start as you reduced speed (CAS: Vc) to about 250kts. It was handy as a reminder that you should select visor down / nose to five below 250kts (the recommendation was as you slowed through 270kts, but latterly we were in the habit of holding at 250kts nose/visor up - I think TCAS was quoted as a backup to the more limited visibility in that config). At takeoff weights, the buffet went at more like 270kts accelerating. So I'm pretty sure there was no vortex lift at AoA > 7 degrees (250kts at LW).
Recommended subsonic cruise at MTOW was F260 / M0.95 which was equal to Vmo of 400kts (CAS). It was best cruise because Vc=400kts was also min drag at MTOW. F280 meant a slightly more draggy speed of 384kts, but some preferred it because when cleared to climb & accelerate supersonic (the official expression was "go for it") it gave you a bit of slack against Vmo when eng put the reheats in. But we tended to ignore the overspeed warning anyway: it was supposed to go really really fast...
We never flew with visor down and nose up unless it was bust - that config was only used during pushback (except one captain who always thought it looked better visor up....). Visor down max Vc was 325kts/M0.8 so it would limit subsonic cruise, and besides it made a racket like that.
It was a beaut in x-winds - a total lack of yaw-roll couple meant you just straightened the 'plane up with rudder and carried on into the flare as normal. No roll to counteract, and the sideways "lift" created by the rudder deflection on the fin pretty much equalled the x-wind drift. Nice.
Wind limits were Crosswind 30kts (15kts contaminated or autoland), Headwind for autoland 25kts (or manual "reduced noise" approach: that's a technical way we used to reduce the noise footprint down to 800' by flying at 190kts then reducing to a target speed of Vref+7kts at that point). Tailwind 10kts. All these limits were, of course, subject to "on the day" performance limits calculated at the time. I seem to remember there was an over-arching limit of 6000' on r/w length, subject again to "on the day" performance limits. OK, I cheated on this paragraph and dug out FM Vol 2a.
There were loads of other limitations which were, by and large, more "esoteric" than a conventional airliner and which had to be learned for the conversion course. It really made the head hurt, and would have been impossible without a big loverrly picture of the beast on the wall chucking out yellow smoke and making noise. Even a static picture of her seemed to make noise...
No one who flew it could really believe their luck, but one thing for sure is "they don't build them like that any more"...
Ahhhhhhhhhhhhhh..........
22nd Sep 2010, 23:54
permalink Post: 447
You had to stop and look.
Quote:
| Having spent the last 11 years based JFK, it never got old to see this magnificient bird arrive and I think to a man, or woman, every one always took a moment to look. |
I have loved aeroplanes since I was very young - I genuinely understood Bernouli's principle when I was about nine - and I always looked at aeroplanes, indeed I still do. But most of the time, when the engine note was obviously a 747 or 727 (noisey!) or some such, I would perhaps concentrate on what I was supposed to be doing. But in the early evening, the absolutely inimitable sound of 593s would draw the eyes of nearly everyone in our area. We saw her every day and yet we all looked. Always. Extraordinary.
Not being in the flying profession, I only have two Concorde stories of my own. Back before the M25 was completed and it stopped at Poyle, I would take the opportunity to use what became the Poyle northbound on ramp as a 'plane spotters' place. One evening I stopped in the gathering dusk and got out to watch a few planes. 737s and 757s abounded as the light faded, leaving a broad, light blue band across the horizon, tinged with peach and little colour anywhere else.
Then I heard her on her way and the old heart beat a bit quicker. Suddenly she was up and passing and my mind's eye took the photograph I always wanted and now will never get.
Concorde, silhouetted against the horizon, the cabin lights just visible, but the four, electric blue reheat exhausts - including shock diamonds - the only other colour in the monochrome image. Unforgettable.
The second was day time. I was parking my car in the north car park - when it was basically all the way down one side of 27R. On my way, I think, to Stockholm Arlander, I was ignoring the succession of 'light iron' going by very close. Again, I heard her light up and just stood and waited. Fabulous sight of Concorde, just rotating as she passed me and climbing away to the west trailing thunder ..... and every car in the north car park sounding their tribute when the reheat set off their alarms.
You just had to look - every time.
Roger.
24th Sep 2010, 14:57
permalink Post: 463
Being from the far side of the pond, my opportunities to see Concorde have been few. But I was privileged to be at Oshkosh in 1985 when Concorde made the first of many appearances at the EAA airshow. After the 1000 mile trip in the back of a 172RG, my world view of aviation was not the most positive. However, Concorde, with the late Captain John Cook at the controls changed all that in an instant.
I remember his approach to Rwy 36 and how quiet the 100,000 or so crowd became. He landed then surprised the crowd will a full reheat touch and go, followed by the always spectacular and precise low level display.
The Concorde stayed parked there for the week with a several hour queue to get a look inside. As I recall they did at least one charter.
I happened to be near the end of the runway during a takeoff and Concorde flew right over me. I have an up-close and personal photo of nothing but the underside of the wing with the undercarriage retracting.
It would be nice if she was still in the air, but at least I get to regularly visit the Air France Concorde on display at IAD.
-Old Ag
I remember his approach to Rwy 36 and how quiet the 100,000 or so crowd became. He landed then surprised the crowd will a full reheat touch and go, followed by the always spectacular and precise low level display.
The Concorde stayed parked there for the week with a several hour queue to get a look inside. As I recall they did at least one charter.
I happened to be near the end of the runway during a takeoff and Concorde flew right over me. I have an up-close and personal photo of nothing but the underside of the wing with the undercarriage retracting.
It would be nice if she was still in the air, but at least I get to regularly visit the Air France Concorde on display at IAD.
-Old Ag