22nd Aug 2010, 15:47
permalink Post: 69
Quote:
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Originally Posted by
Biggles78
...The altitude flown was due to temperature and weight of the areoplane. This is true of all aeroplanes...
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I will see if I can reword it to make it comprehensible.
Thank you for the Instrument Panel image that I have now added to my collection. What is the Yellow Arc on the Mach metre that starts at about M1.12?
Do you remember if you had a signifigant headwind at that stage? I notice that the G/S is 1,139kts was this fairly standard for an East-West flight? (DUH me. Just read the fastest crossing was an east-west direction. Winds must have been quite favorable) I am now guessing the displayed G/S would be fairly typical, plus or minus a bit.
The Glide Ratio, even if it is a highly educated guess, is impressive. I would not have expected it to have been about the same as a B747. How many more times is this Lady going to surprise me with her performance.
Also notice the ball is slightly off to the left even though it is still inside the lines. Was this normal or does it need a tad more rudder trim? Can't imagine it is really out of balance.
Quote:
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Originally Posted by
Bellerophon
Everyone preferred it that way, especially the F/O and F/E!
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ChristiaanJ thanks for the CoG diagram. That I am still getting my head around. There is a large range at the bottom and top of the speed range but fairly narrow in the mid speed range. Seems like 165T was a less complex balancing act than it was at 105T.
The center rear fuselage gear unit, what was that for? I have seen it deployed on many occasions but I can't for the life of me remember if it was during T/O or LDG however it didn't seem to be extended every time the aeroplane flew. Was this used during loading so she didn't accidently "rotate" at the ramp or to avoid a tailstrike during LDG? I can't imagine an over rotate during T/O.
And a big Thank You to Bellerophon for sharing his knowledge with this thread.
26th Aug 2010, 16:43
permalink Post: 132
Quote:
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Originally Posted by
Brit312
Surges were not an uncommon or common event on Concorde, but when they happened - as they usually affected both engines on that side - the aircraft would lurch /yaw and everybody on board would know about it...
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So the prototypes were equipped with "autorudder" computers. They used pressure sensors in the engines to detect engine failures, and they would then kick in a "pre-dosed" amount of rudder, that would then be "washed-out" gradually while the pilot dealt with the issue and added rudder trim.
They were manufactured by SFENA, and since I was their flight test support at Fairford, they became automatically my "babies".
The computers (analog, big boxes, the same size as the autopilots or air intake computers) were extremely reliable (we had only two passive faults during the entire flying career of 002).
Unfortunately the same could not be said of the pressure sensors, and since it was always easier to "pull" a computer than a pressure sensor, we found a computer on the bench every few weeks, which then had to be taken through a full test spec and sent back with "no fault found", before anybody was willing to look at the sensors.
Luckily a better solution was found, using a lateral accelerometer, and from the preprod aircraft onwards, each big separate autorudder computer was replaced by a single board tucked away in the autostab computer.
Since the function was always "on", there was no separate autorudder engage switch. Many years later, I discovered that several airline Concorde pilots did not even know the function existed....
CJ
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
31st Aug 2010, 18:04
permalink Post: 170
DozyWannabe
Good point I suppose, but you could say that the six Concorde prototypes, Pre-Production and Production Series Test aircraft were also development aircraft, and yet more or less worked just as it said on the tin', where the TU144, in spite of all the facilities of Andrei Tupolev's design bureaux, not to mention more or less unlimited Soviet state funds produced a machine that in my opinion really BELONGED in a tin can. (I know this is all off topic, honest guys, I won't mention this stuff again
).
In reality the Soviets really lacked both propulsion technology as well as the systems expertise required to build an aircraft with even a remote hope of Mach 2 cruise, let alone safe and comfortable enough for fare paying passengers. The original aircraft had all for engines in one giant nacelle, and the landing gear retracted into the engine inlet duct itself, great for an undistorted flow path to the engines
. The variable inlets were manually operated by the flight engineer as well, no automatics here. In the mid 1970's the Russians even approached PLESSEY to build a digital engine control unit for the TU144. A similar PLESSEY unit had been VERY successfully flight trialled on production series aircraft 202 (G-BBDG) and only lack of funds prevented it being used on the production aircraft. As this unit could obviously be used for Soviet military applications, there was objection from the UK government, and more than just a little trans-Atlantic pressure applied, and so this venture never happened.
Until the advent of the Mig-29 and Sukhoi SU-27 this really was not the case. I'm afraid I'm with galaxy flyer on this; If you look at the air war over Vietnam, when an F4 met a MIG 19 or MIG 21 in an even air-to-air combat, the MIG was going down. (OK this could be partially down to superior US pilot traing etc, but if you look at the handful of skirmishes where the 1960's/1970's Soviet aircraft were engaged in Combat against US or French built fighters, the MIGs never really did very well at all). However, the aircraft that the Russians have been producing from the Mig 29 onwards seem to be in a completely different class now; hope they really are the good guys now.
ANYWAY, back on topic
Lurking SLF
No problem at all Darragh, please keep visiting us and post here also anytime.
Nick Thomas
I'm not sure that I can describe the DEBOW process remotely as eloquently as my friend Bellerophon did, I particularly loved the 'out of balance tumble-drier' bit, but starting a hot or even warm engine, even at DEBOW, you could certainly 'feel' the noise on the flight deck, until the shaft distortions evened out.
Now for the PFM bit, equally eloquently alluded to by Bellerophon:
DEBOW itself was maintained by a special sub-idle datum in the electronic Engine Control Unit, and once the engine was accelerated towards normal idle (61-65% N2, depending on the temperature of the day) even if the switch described by Bellerophon was accidently re-selected, an electronic inhibit gate in the ECU prevented this sub-idle datum from being used again that engine cycle.
You're welcome Nick, actually the roll and yaw trims operated in a similar manner to the pitch, although of course these was applied by a manual trim wheel only. (No French bike bell either
). Rotation of either wheel (more a giant knob actually) merely shifted the neutral datum of the relevant artificial feel unit, which in turn shifted the rudder pedals or control yoke; the resolvers for the FBW system would in consequence demand this 'trimmed' control surface movement.
Dude
Quote:
| Well, it was essentially a development airframe pressed into premature service for the sake of beating a western project into the air. One wonders whether the story would have been different if the designers had been allowed to take their time and develop it properly. |
).
In reality the Soviets really lacked both propulsion technology as well as the systems expertise required to build an aircraft with even a remote hope of Mach 2 cruise, let alone safe and comfortable enough for fare paying passengers. The original aircraft had all for engines in one giant nacelle, and the landing gear retracted into the engine inlet duct itself, great for an undistorted flow path to the engines
. The variable inlets were manually operated by the flight engineer as well, no automatics here. In the mid 1970's the Russians even approached PLESSEY to build a digital engine control unit for the TU144. A similar PLESSEY unit had been VERY successfully flight trialled on production series aircraft 202 (G-BBDG) and only lack of funds prevented it being used on the production aircraft. As this unit could obviously be used for Soviet military applications, there was objection from the UK government, and more than just a little trans-Atlantic pressure applied, and so this venture never happened.
Quote:
| Those "agricultural" fighters can mix it up with the best the west has to offer (until - or if - the F22 comes online) in terms of manoeuvering ability, if not in terms of weapons. |
ANYWAY, back on topic
Lurking SLF
No problem at all Darragh, please keep visiting us and post here also anytime.
Nick Thomas
Quote:
| 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. |
Now for the PFM bit, equally eloquently alluded to by Bellerophon:
DEBOW itself was maintained by a special sub-idle datum in the electronic Engine Control Unit, and once the engine was accelerated towards normal idle (61-65% N2, depending on the temperature of the day) even if the switch described by Bellerophon was accidently re-selected, an electronic inhibit gate in the ECU prevented this sub-idle datum from being used again that engine cycle.
Quote:
| 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. |
). Rotation of either wheel (more a giant knob actually) merely shifted the neutral datum of the relevant artificial feel unit, which in turn shifted the rudder pedals or control yoke; the resolvers for the FBW system would in consequence demand this 'trimmed' control surface movement.
Dude
3rd Sep 2010, 19:58
permalink Post: 202
ChristiaanJ
During AUTOLAND a flare manoeuvre was instigated by the Pitch Computer at 50' radio, where a fairly simple flare law was invoked. I seem to remember that the law , which used a combination of radio rate (from the RadAlt) and vertical acceleration (from the INS) gave you a commanded height rate of 10'/second at 50', exponentially reducing to 1.7'/second at point of main wheel touch down.
The autoland on Concorde was both extremely accurate and reliable, and an awful lot of guys said they hated using it 'because it can land the aircraft
better than I can'; their words NOT mine. (Personally I never bought that one, the guys were just modest as far as I was concerned
). This in my opinion is an absolute testament to the AFCS designers; ChristiaanJ and his colleagues at SFENA and GEC Marconi.
To give the complete final approach story; as the aircraft tracked the glideslope in LAND mode, the autopilot G/S deviation, like most aircraft, was geared as an inverse function of radio altitude, and at 75' radio this deviation was flushed down the loo altogether, leaving the A/P to hold radio rate for just a few feet. At 50' the flare was instigated, and at around 35' DECRAB was commanded, where the yaw channel would use a rudder input alone to 'kick off drift' and align the aircraft with the runway centreline. (Concorde did not employ a fwd slip manoeuvre in crosswind conditions, being a slender delta). The 'final' command was at 15' radio, when the autothrottle smartly retarded the throttles. (The Pitch Computer flare law of course continuing to control decent rate all the way down). On touchdown the autopilot would be manually disengaged and the nose gently (usually
) lowered to the ground. (Concorde was only designed and certified as a CAT 3A system, so there was no automatic rollout guidance. However there was a runway guidance symbol on the ADI, which used a combination of Localiser deviation and lateral acceleration, to give you runway rollout track).
Now the flare law was tested every autoland, at G/S capture, and failure of this test resulted in the loss of LAND 3 status on the landing display panel. The most common defect of all with the Concorde autoland was in fact failure of the flare test, when at G/S capture, the previously illuminated LAND 3 indication would drop all of it's own to LAND 2. A simple changeover of autopilot paddle switches would nail the offending Pitch Computer, which would then be replaced before the next trip.
Dude
Quote:
| During landing, Concorde isn't flared at all, it is flown onto the ground at a constant pitch attitude. |
The autoland on Concorde was both extremely accurate and reliable, and an awful lot of guys said they hated using it 'because it can land the aircraft
better than I can'; their words NOT mine. (Personally I never bought that one, the guys were just modest as far as I was concerned
). This in my opinion is an absolute testament to the AFCS designers; ChristiaanJ and his colleagues at SFENA and GEC Marconi.
To give the complete final approach story; as the aircraft tracked the glideslope in LAND mode, the autopilot G/S deviation, like most aircraft, was geared as an inverse function of radio altitude, and at 75' radio this deviation was flushed down the loo altogether, leaving the A/P to hold radio rate for just a few feet. At 50' the flare was instigated, and at around 35' DECRAB was commanded, where the yaw channel would use a rudder input alone to 'kick off drift' and align the aircraft with the runway centreline. (Concorde did not employ a fwd slip manoeuvre in crosswind conditions, being a slender delta). The 'final' command was at 15' radio, when the autothrottle smartly retarded the throttles. (The Pitch Computer flare law of course continuing to control decent rate all the way down). On touchdown the autopilot would be manually disengaged and the nose gently (usually
) lowered to the ground. (Concorde was only designed and certified as a CAT 3A system, so there was no automatic rollout guidance. However there was a runway guidance symbol on the ADI, which used a combination of Localiser deviation and lateral acceleration, to give you runway rollout track).
Now the flare law was tested every autoland, at G/S capture, and failure of this test resulted in the loss of LAND 3 status on the landing display panel. The most common defect of all with the Concorde autoland was in fact failure of the flare test, when at G/S capture, the previously illuminated LAND 3 indication would drop all of it's own to LAND 2. A simple changeover of autopilot paddle switches would nail the offending Pitch Computer, which would then be replaced before the next trip.
Dude
7th Sep 2010, 00:15
permalink Post: 242
I have two recollections which I treasure. The first is of a sales demo ride for a VIP party I had to organise from Abu Dhabi on 29th August 1974; one by one we went to the flight deck to look around, which is when I first saw the gap by the F/E panel as the skin stretched. The flight took us overhead Dubai and then halfway to Bombay with a level turn at M2 and back along the outward track. The contrail was close by the RH side and gave a tremendous impression of what the speed really meant.
Some 13 or 14 years later I had the privilege of a jump seat ride from Exeter for the whole of one of the round-the-bay flights. We flew North to join the westbound route to the acceleration point at minimum separation behind the schedule Concorde to New York (or perhaps Washington?). The display as the other aircraft's nose lifted and the aircraft accelerated was awesome.
Then on landing, handflown by the FO (currency requirement?), we seemed to be heading for a touchdown halfway down the runway. It was truly terrifying to a simple PPL, and just as I was about to let out a strangled sob the mainwheels touched down precisely on the markers, well below and behind. Apart from the terror, what impressed me was that as far as I could see the FO was flying the aircraft exactly as you would a Tiger Moth; stick, throttle and rudder. I know that there was far more to it than that, but that's how it appeared.
What a gorgeous aircraft. My model, in its original Gulf Air colours as presented in 1974, flies in the ceiling of my office.
Some 13 or 14 years later I had the privilege of a jump seat ride from Exeter for the whole of one of the round-the-bay flights. We flew North to join the westbound route to the acceleration point at minimum separation behind the schedule Concorde to New York (or perhaps Washington?). The display as the other aircraft's nose lifted and the aircraft accelerated was awesome.
Then on landing, handflown by the FO (currency requirement?), we seemed to be heading for a touchdown halfway down the runway. It was truly terrifying to a simple PPL, and just as I was about to let out a strangled sob the mainwheels touched down precisely on the markers, well below and behind. Apart from the terror, what impressed me was that as far as I could see the FO was flying the aircraft exactly as you would a Tiger Moth; stick, throttle and rudder. I know that there was far more to it than that, but that's how it appeared.
What a gorgeous aircraft. My model, in its original Gulf Air colours as presented in 1974, flies in the ceiling of my office.
19th Sep 2010, 18:53
permalink Post: 401
Quote:
|
Originally Posted by
Bellerophon
I'm not aware of what Haynes may say about Concorde - I don't have a copy of the book and haven't read it - however it is well documented that landings at weights up to 130,000 kgs were permitted on Concorde, provided various conditions were met.
It was a Conditional Procedure called Fuel Saving Landing . BA did not plan flights to land at 130,000 kgs but the procedure was available for use when required. In practice it was rarely used, and the occasions on which it was used tended to be following a return to the departure airfield, or a diversion in the early part of the flight, with the aircraft still above the (normal) maximum landing weight, in order to reduce the amount of fuel to be jettisoned. |
By the way, I highly recommend this book to everybody, a different point of view, new photos and nice info regarding this bird.
Quote:
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Originally Posted by
M2Dude
Hi again. Yes, the Ronivaniemi charters were supersonic) and VERY popular).
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Nice info regarding BA004! But if a repair was needed, would BA004 take-off anyway to Gatwick or Birmingham? Has it ever arrived a bit late?
Quote:
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Originally Posted by
ChristiaanJ
My own question to an aerodynamicist would be :
Looking at the subtle camber of the leading edge, is there any vortex lift at all during subsonic cruise (Mach 0.95+) or is there a fully attached airflow at that speed / angle of attack to obtain the best possible subsonic cruise? And if so, when does the breakaway first start? |
Quote:
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Originally Posted by
Jo90
Was there some particular airspeed where the airflow pattern changed markedly?
|
Thank you all, awesome topic!!
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..........
20th Sep 2010, 23:48
permalink Post: 434
Nick - good question. The elevons were not hidden at high AoA (no elevators, no T-tail issue) but high alpha longitudinal stability was an issue in early development, one of the fixes were the moustache strakes you see at the front - they help energise the wing vorteces and improve rudder authority at high AoA. Apparently. Well that's what they told us at ground school - the result was that right up to limiting AoA all flight controls were effective, including the potentially blanked-off rudder. IIRC the stick-shake was at about 16 degrees which left about 3 degrees slack above approach AoA and it all worked just fine in that environment.
21st Sep 2010, 00:07
permalink Post: 435
Finally, after 3 nights reading this thread in my spare time i've come to the end of it (for now - it's an organic thing!) and i'd just like to echo the thanks from a wide-eyed SLF who always ran outside of my house every time she went overhead twice a day - and what a noise
Anyway, I have 2 questions to put to the assembled experts:
1) Earlier it was mentioned that the tailwheel was the only piece of bad design on the Concorde. Does this mean that the rudder failures were as a result of corrosion/fatigue of a sound original design and that it was just a bit of bad luck that nobody could have foreseen? also, how easy was it to remedy?
2) Were the rudder separation and the in-flight "hole in the wing" issue (reported on the Concorde TV programme) the most serious issues experienced during service? or were there any other issues which manifested themselves such that the passengers were oblivious but the crew were more than a little concerned?
Thanks!
Mike.
(p.s. - my wife's still chuckling at the Prince Philip story)
Anyway, I have 2 questions to put to the assembled experts:
1) Earlier it was mentioned that the tailwheel was the only piece of bad design on the Concorde. Does this mean that the rudder failures were as a result of corrosion/fatigue of a sound original design and that it was just a bit of bad luck that nobody could have foreseen? also, how easy was it to remedy?
2) Were the rudder separation and the in-flight "hole in the wing" issue (reported on the Concorde TV programme) the most serious issues experienced during service? or were there any other issues which manifested themselves such that the passengers were oblivious but the crew were more than a little concerned?
Thanks!
Mike.
(p.s. - my wife's still chuckling at the Prince Philip story)
21st Sep 2010, 18:06
permalink Post: 443
For Mike_Bracknell
The rudder failures weren't really down to a fault with the original design, here's the story as I remember it:
The ctrl surfaces are made of a honeycomb-core bonded to the skins, essentially. They originally had a blunt trailing-edge, as was then de-rigeur with supersonic design. At some stage it was decided that a sharp trailing edge was actually beneficial so they had an extension fitted, which had the unfortunate effect of allowing a certain amount of water ingress to the core. Heating and expansion of this lead to disbonding and ultimately failure of the surfaces. (I suspect my engineering colleagues will have a much better and more accurate explanation).
Now - here's the important bit, and another example of this aeroplane's excellent failsafe engineering; Concorde had two rudders, one above the other (same as the 747). Each is driven by one dual-bodied PFCU. You ABSOLUTELY don't want a PFCU endangered by ctrl surface damage so each surface is divided in two, either side of the PFCU control horn.
Visualise the PFCU attached to the centre of two surfaces with an end rib on each, but skinned to look like one surface. Therefore, in the case of the surface suffering damage, it can only spread to a point short of the all-important PFCU. Look at the rudder-failure pictures and you'll see what I mean.
So - far from the 'rudder' breaking up, the reality is that half of one of the rudders had failed.
It was somewhat inevitable that Concorde's control sfcs would suffer, given the horrific loads they endured, and this was dealt with at the design stage. The elevons had the same sort of design.
It does of course look bad when you land with bits missing and this, plus the Regulators and company safety depts ensured that eventually some HUGELY expensive replacements were built.
The ctrl surfaces are made of a honeycomb-core bonded to the skins, essentially. They originally had a blunt trailing-edge, as was then de-rigeur with supersonic design. At some stage it was decided that a sharp trailing edge was actually beneficial so they had an extension fitted, which had the unfortunate effect of allowing a certain amount of water ingress to the core. Heating and expansion of this lead to disbonding and ultimately failure of the surfaces. (I suspect my engineering colleagues will have a much better and more accurate explanation).
Now - here's the important bit, and another example of this aeroplane's excellent failsafe engineering; Concorde had two rudders, one above the other (same as the 747). Each is driven by one dual-bodied PFCU. You ABSOLUTELY don't want a PFCU endangered by ctrl surface damage so each surface is divided in two, either side of the PFCU control horn.
Visualise the PFCU attached to the centre of two surfaces with an end rib on each, but skinned to look like one surface. Therefore, in the case of the surface suffering damage, it can only spread to a point short of the all-important PFCU. Look at the rudder-failure pictures and you'll see what I mean.
So - far from the 'rudder' breaking up, the reality is that half of one of the rudders had failed.
It was somewhat inevitable that Concorde's control sfcs would suffer, given the horrific loads they endured, and this was dealt with at the design stage. The elevons had the same sort of design.
It does of course look bad when you land with bits missing and this, plus the Regulators and company safety depts ensured that eventually some HUGELY expensive replacements were built.
29th Oct 2010, 16:25
permalink Post: 627
jodelistie
First of all Rod, welcome to our Concorde thread, and thank you very much for your kind words.
Now as far as the rumour goes, I'm afraid that it is nonsense, however the truth is an even more complex story of collusion, betrayal and intrigue. You may read that 'Concorde was retired by BA and Air France purely due to economic reasons', however that is not quite the case (and as far as THIS side of the English Puddle goes, is total poppycock!!). Now BA lost a huge amount of her regular traffic as a result of the 9/11 tragedy and also as a result of the 2003 Iraq war, but things were improving nicely. In her 27 years of operation, Concorde had survived countless dips in her traffic, only to return stronger as market conditions improved.
It is early 2003, and French Concorde traffic to the USA has almost vanished, down to single digit loads. This is due mainly to total French opposition the impending US/UK invasion of Iraq, and US businessmen using BA Concorde almost exclusively. (French business seems to be boycotting the US altogether, so their contribution to passenger loads virtually ceased). Due to the apalling loads, AF are losing absolutely MILLIONS of Euros, at a time when the carrier is trying to privatise itself ... but there is more:
In the same February, AF very nearly lost ANOTHER Concorde, yet again largely down to total incompetence and lack of adherence to established procedures. Aircraft F-BTSD was flying between CDG and JFK when there was a failure of the reheat delivery pipe that runs from the engine 1st stage fuel pump to the reheat shut-off valve. This failure, although not particularly serious, led to a chain of events that very nearly resulted in the loss of the aircraft, and all those onboard. (Air France engines were overhauled seperately to BA, who never experienced this particular failure). What was required in the case of this failure was a precautionary engine shut-down, closing off the fuel supply to the engine totally, and a descent/deceleration to subsonic speed, carefully monitoring fuel consumption all the time. Unfortunately the crew 'forgot' to shut down the fuel LP valve, and this resulted in the fuel continuing to gush out of the failed pipe at an alarming rate. (Oh, and also they forgot to monitor the fuel consumption). Only after the crew FINALLY noticed that they were still losing fuel did they remember to close the engine LP valve, but it was almost too late. The aircraft just managed to land in Halifax, with barely enough fuel left in the tanks to taxi!! So, herer we are, AF are horrified that they have come very close to yet another disaster, knowing full well that yet again human error was a major factor.
But there is more....
One week later another AF aircraft loses part of a rudder panel due to de-lamination of the honeycomb surface, not particularly serious in itself, but it put even more jitters up the trousers of AF. (Rudder failures had happened to BA aircraft many years previous to this, but BA had purchased brand new and improved rudders from Airbus UK in Filton, but Air France chose not too).
So it seems that the chairmen of both Air France and Airbus (who regards Concorde as a waste of its valuable resources) have a 'secret' meeting to plan what was effectively the murder of Concorde. There is no way that AF want BA to carry on flying Concorde while they have to cease operations, so the plan is for Airbus to make a huge hike in their product support costs; these costs would have to be borne by BA exclusively, which they both knew would not be possible. If these support costs were not met, there would be no manufacturers support, and without this there would be no type certificate, and without this, no more Concorde.
Their (AF & Airbus) hope was that BA would not challenge this move legally, and sadly for the world of aviation they did not. At a meeting, BA AND AIR FRANCE!!!! were told by Airbus about the hike in product support costs, and BA would also have to cease operations. BA were not even allowed to continue until March 2004 (the Barbados season was nearly fully booked already), and so would have to cease operations in October 2003.
But the British were far from blameless in all this; a now retired very senior British airline person had always obsessively HATED Concorde, so the French conspiracy was a very early Christmas present for him; he finally got what he had always wanted. The 'end of Concorde' anouncement by both airlines was made in April 2003; AF had got what their executives wanted and finished flying in May, reluctantly leaving BA to fly until late October. If you want a full (and extremely well informed) explanation of what happened in that whole debacle, the article by Don Pevsner is worth reading. It can be found at this website:
THE BETRAYAL OF CONCORDE
There is absolutely no doubt in my mind that without the truly disgusting events in France in early 2003, Concorde would still be proudly flying for BA. (And with modifications and enhancements would fly safely for many more years).
quote** "in the hands of true professionals, Concorde was the safest aircraft that ever flew. and in the hands of BA crews at least, she was always just that..*
Oh and yes you were correct, the Olympus (the world's first ever 2 spool engine) was originally a 'Bristol-Siddeley' design, before BS were absorbed into Rolls-Royce. Stanley Hookers book is in my view totally superb, a true classic.
Dude
Quote:
| On which there was a splendid rumour that what put the final nail in the great birds coffin was that our transatlantic allies realised that if hijacked there was nothing that could catch her !! |
Now as far as the rumour goes, I'm afraid that it is nonsense, however the truth is an even more complex story of collusion, betrayal and intrigue. You may read that 'Concorde was retired by BA and Air France purely due to economic reasons', however that is not quite the case (and as far as THIS side of the English Puddle goes, is total poppycock!!). Now BA lost a huge amount of her regular traffic as a result of the 9/11 tragedy and also as a result of the 2003 Iraq war, but things were improving nicely. In her 27 years of operation, Concorde had survived countless dips in her traffic, only to return stronger as market conditions improved.
It is early 2003, and French Concorde traffic to the USA has almost vanished, down to single digit loads. This is due mainly to total French opposition the impending US/UK invasion of Iraq, and US businessmen using BA Concorde almost exclusively. (French business seems to be boycotting the US altogether, so their contribution to passenger loads virtually ceased). Due to the apalling loads, AF are losing absolutely MILLIONS of Euros, at a time when the carrier is trying to privatise itself ... but there is more:
In the same February, AF very nearly lost ANOTHER Concorde, yet again largely down to total incompetence and lack of adherence to established procedures. Aircraft F-BTSD was flying between CDG and JFK when there was a failure of the reheat delivery pipe that runs from the engine 1st stage fuel pump to the reheat shut-off valve. This failure, although not particularly serious, led to a chain of events that very nearly resulted in the loss of the aircraft, and all those onboard. (Air France engines were overhauled seperately to BA, who never experienced this particular failure). What was required in the case of this failure was a precautionary engine shut-down, closing off the fuel supply to the engine totally, and a descent/deceleration to subsonic speed, carefully monitoring fuel consumption all the time. Unfortunately the crew 'forgot' to shut down the fuel LP valve, and this resulted in the fuel continuing to gush out of the failed pipe at an alarming rate. (Oh, and also they forgot to monitor the fuel consumption). Only after the crew FINALLY noticed that they were still losing fuel did they remember to close the engine LP valve, but it was almost too late. The aircraft just managed to land in Halifax, with barely enough fuel left in the tanks to taxi!! So, herer we are, AF are horrified that they have come very close to yet another disaster, knowing full well that yet again human error was a major factor.
But there is more....
One week later another AF aircraft loses part of a rudder panel due to de-lamination of the honeycomb surface, not particularly serious in itself, but it put even more jitters up the trousers of AF. (Rudder failures had happened to BA aircraft many years previous to this, but BA had purchased brand new and improved rudders from Airbus UK in Filton, but Air France chose not too).
So it seems that the chairmen of both Air France and Airbus (who regards Concorde as a waste of its valuable resources) have a 'secret' meeting to plan what was effectively the murder of Concorde. There is no way that AF want BA to carry on flying Concorde while they have to cease operations, so the plan is for Airbus to make a huge hike in their product support costs; these costs would have to be borne by BA exclusively, which they both knew would not be possible. If these support costs were not met, there would be no manufacturers support, and without this there would be no type certificate, and without this, no more Concorde.
Their (AF & Airbus) hope was that BA would not challenge this move legally, and sadly for the world of aviation they did not. At a meeting, BA AND AIR FRANCE!!!! were told by Airbus about the hike in product support costs, and BA would also have to cease operations. BA were not even allowed to continue until March 2004 (the Barbados season was nearly fully booked already), and so would have to cease operations in October 2003.
But the British were far from blameless in all this; a now retired very senior British airline person had always obsessively HATED Concorde, so the French conspiracy was a very early Christmas present for him; he finally got what he had always wanted. The 'end of Concorde' anouncement by both airlines was made in April 2003; AF had got what their executives wanted and finished flying in May, reluctantly leaving BA to fly until late October. If you want a full (and extremely well informed) explanation of what happened in that whole debacle, the article by Don Pevsner is worth reading. It can be found at this website:
THE BETRAYAL OF CONCORDE
There is absolutely no doubt in my mind that without the truly disgusting events in France in early 2003, Concorde would still be proudly flying for BA. (And with modifications and enhancements would fly safely for many more years).
quote** "in the hands of true professionals, Concorde was the safest aircraft that ever flew. and in the hands of BA crews at least, she was always just that..*
Oh and yes you were correct, the Olympus (the world's first ever 2 spool engine) was originally a 'Bristol-Siddeley' design, before BS were absorbed into Rolls-Royce. Stanley Hookers book is in my view totally superb, a true classic.
Dude
Last edited by M2dude; 29th Oct 2010 at 16:52 . Reason: spelling (yet again) :-(
5th Nov 2010, 11:56
permalink Post: 663
I have to admit that some of the subsonic fuel burn figures for Concorde were truly eye watering, and without massive engine and airframe modifications there was precious little in service that could be done to improve things. Paradoxically improvements to the
supersonic
efficiency of the powerplant were easier to implement, and several modifications were implemented, tried or proposed to improve fuel burn:
Way back in the late 1970's we did a major modification to the intakes that increased capture area by 2.5% and gave us typically a 1.6% improvement in trans-Atlantic fuel burn, and although this was our biggest performance improvement modification, there were more:
The famous elevon and rudder trailing edge extension modifications (that due to poor design, produced in later life the water ingress induced honeycomb failures) together with the re-profiled fin leading edge modification, I never saw the performance gains quantified (anyone have any ideas?).
Can anyone here remember the riblet trial? In the mid 1990's Airbus supplied 'stick on' plastic riblets, applied to various areas on the under-side of the wing on G-BOAG. These riblets had very fine undulations moulded into the surface; the idea being that as the air flowed through and around the riblet patches, boundary layer turbulence, and hence induced drag would be reduced. Now, the performance gains (if any) were never quantified, mainly because the riblet patches either peeled off or the surface deteriorated with the continuous thermal cycle. (I was over in JFK when the aircraft first arrived after having the riblets fitted, and as the crew were trying to proudly show me these amazing aerodynamic devices, they were sadly embarassed, as several had dissapeared in the course of a single flight).
There was one modification, proposed by Rolls Royce in the late 1990's that did have quite a lot of potential; this was to increase the engine N1 by around 1.5%. This would have had the effect of increasing engine mass flow and therefore reducing the drag inducing spill of supersonic air over the lower lip of the intake. Depending on the temperature, the performance gains were in the order of a 1.5% improvement in fuel burn at ISA Plus upper atmosphere temperatures ('normal' LHR-JFK) to none at all at significant ISA Minus temperatures (LHR -BGI). The modifacation had been trialed on G-BBDG before her retirement in the early eighties, and was proven in terms of performance enhancement and engine stability. In order to keep TET at the pre-modification level, there was a small increase in N2 commanded also. (The higher N1 required an increase in primary nozzle area, reducing TET). The main reason for the modification not being implemented was one of cost; The Ultra Electronics Engine Control Units were analog units, and the modification was a simple replacement of two resistors per unit. However because ultimate mass flow limitation was also controll by the digital AICU (built by British Aerospace Guided Weapons Division) the cost of getting a software update for this exremely 'mature' unit was found to be prohibitive.
A certain 'brainy' SEO and myself were working on a modification to improve fuel burn on ISA minus sectors. The idea was to force the autopilot, in Max Cruise at low temperatures only , to fly the aircraft close to Mmo, rather than at Max Cruise speed of Mach 2 - 2.02; this would have given us gains of up to 1%, depending on the temperature. The basic electronics involved for the modification were relatively straightforward, but it was never pursued due to the complexity of dealing with temperature shears and the cost of certification.
Dude
Way back in the late 1970's we did a major modification to the intakes that increased capture area by 2.5% and gave us typically a 1.6% improvement in trans-Atlantic fuel burn, and although this was our biggest performance improvement modification, there were more:
The famous elevon and rudder trailing edge extension modifications (that due to poor design, produced in later life the water ingress induced honeycomb failures) together with the re-profiled fin leading edge modification, I never saw the performance gains quantified (anyone have any ideas?).
Can anyone here remember the riblet trial? In the mid 1990's Airbus supplied 'stick on' plastic riblets, applied to various areas on the under-side of the wing on G-BOAG. These riblets had very fine undulations moulded into the surface; the idea being that as the air flowed through and around the riblet patches, boundary layer turbulence, and hence induced drag would be reduced. Now, the performance gains (if any) were never quantified, mainly because the riblet patches either peeled off or the surface deteriorated with the continuous thermal cycle. (I was over in JFK when the aircraft first arrived after having the riblets fitted, and as the crew were trying to proudly show me these amazing aerodynamic devices, they were sadly embarassed, as several had dissapeared in the course of a single flight).
There was one modification, proposed by Rolls Royce in the late 1990's that did have quite a lot of potential; this was to increase the engine N1 by around 1.5%. This would have had the effect of increasing engine mass flow and therefore reducing the drag inducing spill of supersonic air over the lower lip of the intake. Depending on the temperature, the performance gains were in the order of a 1.5% improvement in fuel burn at ISA Plus upper atmosphere temperatures ('normal' LHR-JFK) to none at all at significant ISA Minus temperatures (LHR -BGI). The modifacation had been trialed on G-BBDG before her retirement in the early eighties, and was proven in terms of performance enhancement and engine stability. In order to keep TET at the pre-modification level, there was a small increase in N2 commanded also. (The higher N1 required an increase in primary nozzle area, reducing TET). The main reason for the modification not being implemented was one of cost; The Ultra Electronics Engine Control Units were analog units, and the modification was a simple replacement of two resistors per unit. However because ultimate mass flow limitation was also controll by the digital AICU (built by British Aerospace Guided Weapons Division) the cost of getting a software update for this exremely 'mature' unit was found to be prohibitive.
A certain 'brainy' SEO and myself were working on a modification to improve fuel burn on ISA minus sectors. The idea was to force the autopilot, in Max Cruise at low temperatures only , to fly the aircraft close to Mmo, rather than at Max Cruise speed of Mach 2 - 2.02; this would have given us gains of up to 1%, depending on the temperature. The basic electronics involved for the modification were relatively straightforward, but it was never pursued due to the complexity of dealing with temperature shears and the cost of certification.
Dude
Last edited by M2dude; 5th Nov 2010 at 15:49 .
7th Nov 2010, 01:04
permalink Post: 675
Odd question this which requires a bit of background to give authenticity.
When I could afford to fly R22s from an airfield neat Stratford on Avon the Heli company\x92s owner\x92s son attended some kind of auction of Concorde parts and came back with part (or all) of a Concorde rudder which was duly mounted on the hanger wall.
I gazed long and hard at it (closest I ever got to the supreme lady) and noticed a series of mysterious \x91bolts\x92 sticking out of the rear edge of the rudder. One of the helicopter engineers present rubbed his beard thoughtfully and surmised they may be \x91static wicks\x92 \x96 but nobody present was really sure.
All this of course went straight over my head but whilst they were all on tea break I managed to chip of a couple of flecks of deep blue paint from the rudder and stash them in a match box. (Back in Birmingham later that evening I sat with friends in the garden of the 'Rose and Crown' and we all touched reverentially those paint chips that had been places we could only dream of \x96 but I digress).
What were those bolt like things on the trailing edge of the rudder?
When I could afford to fly R22s from an airfield neat Stratford on Avon the Heli company\x92s owner\x92s son attended some kind of auction of Concorde parts and came back with part (or all) of a Concorde rudder which was duly mounted on the hanger wall.
I gazed long and hard at it (closest I ever got to the supreme lady) and noticed a series of mysterious \x91bolts\x92 sticking out of the rear edge of the rudder. One of the helicopter engineers present rubbed his beard thoughtfully and surmised they may be \x91static wicks\x92 \x96 but nobody present was really sure.
All this of course went straight over my head but whilst they were all on tea break I managed to chip of a couple of flecks of deep blue paint from the rudder and stash them in a match box. (Back in Birmingham later that evening I sat with friends in the garden of the 'Rose and Crown' and we all touched reverentially those paint chips that had been places we could only dream of \x96 but I digress).
What were those bolt like things on the trailing edge of the rudder?
7th Nov 2010, 07:34
permalink Post: 677
Cron
Sounds like the helicopter engineer's guess was right, they'd be the static wick mountings.
Feathers McGraw
Yes there was, that was the problem alright Feathers. I'd only heard an engine stuck in rotating stall during startup once; even on the flight deck it sounded like a tom cat with his gonads trapped in a vice, and we shut the thing down straight away. (The engine, not the tom cat
).
It was mainly a case of increased vigilance during engine start; it was always noticable to see rotating stall clearance on startup as the N2 went past normal idle and then rolled back. As far as modifications go, I'd designed a modification to detect and alert the crew if rotating stall had not been cleared on startup, but it was felt to be too costly and complex, when increased vigilance by all could prevent the nasty event happening in the first place. (I suppose only one BA occurence in 27 years is not so bad, and if the automatics did their job you had no problem anyway). But now at least EVERYBODY was aware of the malignant consequences of not clearing rotating stall on startup; it was no longer just a phrase that we all learned in training, but scary reality.
Dude
Quote:
| I gazed long and hard at it (closest I ever got to the supreme lady) and noticed a series of mysterious \x91bolts\x92 sticking out of the rear edge of the rudder. One of the helicopter engineers present rubbed his beard thoughtfully and surmised they may be \x91static wicks\x92 \x96 but nobody present was really sure. |
Feathers McGraw
Quote:
| I assume that there must have been some sort of fuel control failure for a sub-idle N2 to establish with the engine lit. |
).
Quote:
| What steps were taken to prevent his happening again? Modification of the fuel control scheduling or something else? |
Dude
10th Nov 2010, 13:04
permalink Post: 691
All due respect but this is the CONCORDE thread and it would be really nice if it could stay as such. If you wish to debate wing technology of other aeroplanes then please I would suggest a new thread be started on that subject. I daresay it would also make for an interesting discussion.
-----------------------------------------------------------------------
LandLady said in a post many moons ago that there was a pool of some 240 "Concorde Ambassadors" (sorry but CC and FAs don't sound right for this aeroplane) for Her. What was the numbers of Captains, First Officers and the all important Flight Engineers (sucking up to M2 with that one
)
Does anyone know how long did it take to fly from NZ (AKL if I remember correctly) to SYD (very early 90s I think). It is about the same distance at John O Groats to Lands End so I am guessing the 20 to 25 minute mark and how did the 2mt piece of rudder parting company with the fuselage at Mach 2.04 over the Tasman Sea affect or effect the handling characteristics? I remember the papers saying it was hardly a noticable event but I suspect the BA publicity department had a hand with that information.
I looked at the photos posted by a thoughtful member in an earlier post and wonder how former crew felt looking at them. The photos give the impression that you could kick the tyres and light the fires and they would be once again gracing the skies. Obviously they are unairworthy BUT the photos project a different image.
Final one for this post. If She was still flying, do you still think that BA (sorry but going to ignore AF on this one) would have sufficient patronage to keep Her as a going and profitable concern?
-----------------------------------------------------------------------
LandLady said in a post many moons ago that there was a pool of some 240 "Concorde Ambassadors" (sorry but CC and FAs don't sound right for this aeroplane) for Her. What was the numbers of Captains, First Officers and the all important Flight Engineers (sucking up to M2 with that one
)
Does anyone know how long did it take to fly from NZ (AKL if I remember correctly) to SYD (very early 90s I think). It is about the same distance at John O Groats to Lands End so I am guessing the 20 to 25 minute mark and how did the 2mt piece of rudder parting company with the fuselage at Mach 2.04 over the Tasman Sea affect or effect the handling characteristics? I remember the papers saying it was hardly a noticable event but I suspect the BA publicity department had a hand with that information.
I looked at the photos posted by a thoughtful member in an earlier post and wonder how former crew felt looking at them. The photos give the impression that you could kick the tyres and light the fires and they would be once again gracing the skies. Obviously they are unairworthy BUT the photos project a different image.
Final one for this post. If She was still flying, do you still think that BA (sorry but going to ignore AF on this one) would have sufficient patronage to keep Her as a going and profitable concern?
10th Nov 2010, 13:56
permalink Post: 692
Biggles
I think the rudder failure incident was covered in Brian Calvert's book, "Flying Concorde".
IIRC, after the rudder failed and separated the first indication of a problem was during deceleration, a light buffet or buzzing sensation was detected by the flight crew. There was no indication of the problem other than this.
The crew was informed of the problem by the tower during their landing, but I don't remember whether this was during the approach or once on the runway.
I think the rudder failure incident was covered in Brian Calvert's book, "Flying Concorde".
IIRC, after the rudder failed and separated the first indication of a problem was during deceleration, a light buffet or buzzing sensation was detected by the flight crew. There was no indication of the problem other than this.
The crew was informed of the problem by the tower during their landing, but I don't remember whether this was during the approach or once on the runway.
24th Nov 2010, 13:43
permalink Post: 764
Quote:
|
Originally Posted by
speedbirdconcorde
Regarding the rather important role of the elevons on Concorde
were there any failures during her time in the skies ?
|
M2dude may already have the details of "where", "when" and "how many" at his fingertips.
Otherwise a Google, with terms such as 'AAIB', 'DGAC', 'elevon failure' and suchlike in the query, should get you the answers.
The failures were similar to the rudder failures: part of the trailing edge of an elevon parting company with the aircraft, noticeable because of vibration, but without dire consequences.
CJ
18th Dec 2010, 15:20
permalink Post: 876
JFK 31L, Kennedy 9 Departure, Canarsie transition, Concorde climb
Speedbird 2, cleared take-off 31L.
You call 3-2-1 Now , start your stopwatch, pre-set to countdown from 58 seconds, and slam the throttles fully forward till they hit the stops. Four RR Olympus engines start to spool up to full power and four reheats kick in, together producing 156,000 lbs of thrust, but at a total fuel flow of 27,000 US gallons per hour. A touch of left rudder initially to keep straight, as the #4 engine limiter is limiting the engine to 88% until 60 kts when it will release it to full power. The F/O calls Airspeed building, 100 kts, V 1 , and then, at 195 kts, Rotate . You smoothly rotate the aircraft, lift-off occurs at around 10\xb0 and 215 kts. You hear a call of V 2 but you keep rotating to 13.5\xb0 and then hold that attitude, letting the aircraft accelerate.
The F/O calls Positive Climb and you call for the Gear Up . On passing 20 feet radio height, and having checked the aircraft attitude, airspeed and rate of climb are all satisfactory, the F/O calls Turn and you slowly and smoothly roll on 25\xb0 left bank to commence the turn out over Jamaica bay. Some knowledgeable passengers will have requested window seats on the left side of the aircraft at check-in, and are now being rewarded with a very close look at the waters of Jamaica Bay going by very fast! As you accelerate through 240 kts, the F/O calls 240 and you pitch up to 19\xb0 to maintain 250 kts and keep the left turn going to pass East of CRI.
54 seconds from the start of the take off roll you hear the F/O counting down 3-2-1 Noise whereupon the F/E cancel the re-heats and simultaneously throttles back to noise abatement power, around 96% as you pitch the nose down to 12\xb0 to maintain 250 kts. It is less than a minute from start of roll and already 435 US gallons of fuel have been used.
Speedbird 2, contact departure, so long.
Turning through heading 235\xb0M, the F/E quickly re-applies full dry power as you pitch up to 17\xb0 to maintain 250 kts, but simultaneously reduce the left bank to 7.5\xb0, in order to increase both the radius of turn (to stay on the optimum noise abatement track) and the rate of climb (less bank, higher RoC).
On climbing through 2,500 ft you increase the bank angle back to 25\xb0 left bank and as you approach the 253\xb0 radial JFK, you hear 3-2-1 Noise from the F/O for the second time. The F/E actions the second noise-abatement power cut back, you pitch down to 12\xb0 and, if not in cloud, sneak a quick peek out of your left hand window, looking for the car park by the Marine Parkway bridge, as you would ideally like to pass right over the car park, if possible, as we tip-toe quietly across the Rockaway Beaches, in order to minimise the noise impact on the residents.
Keep the left turn going and intercept the 176\xb0 radial outbound from CRI, and at 5 miles DME from CRI, call for the F/E to slowly re-apply full climb power as you pitch up to maintain 250 kts. We are still in US territorial airspace, below 10,000 ft, and subject to statutory speed control.
Speedbird 2, present position direct to SHIPP, climb FL230, no speed control.
The F/O selects direct SHIPP in the INS and tells you that she has selected that information into your Flight Director. Having checked that the gear lever is at neutral, you call for the Nose Up , and then the Visor Up . Flight deck noise levels drop dramatically as the Visor locks up. Now more than 12 miles away from the coast, we are clear of US speed control requirements so lower the attitude to 9\xb0, accelerate to V MO , currently 400 kts, and ask for the After Take Off Checks.
Speedbird 2, present position direct to LINND, climb in the block FL550-600, accelerate Mach 2.0
Call for the Climb Checklist at Mach 0.7, which will trigger the F/E to start pumping fuel rearwards to move the CG aft, then when he's done that, straight into the Transonic Checklist . Maintain 400 kts IAS, and around 24,500 ft, at M0.93, ask for the re-heats back on, in pairs, and raise the nose by 3\xb0 to maintain 400 kts as they kick in.
Precise, smooth flying is required through the high drag transonic region, as the mach meter creeps up towards Mach 1. A sudden flicker on the VSI and Altimeter confirms that the shock wave has just passed over the static ports, and the aircraft is now supersonic. A quick glance at the elapsed time indicator shows that you\x92ve been hand flying for just over 9 minutes since the start of the take off roll.
Another fun start to a day in the office, and to think we got paid for doing it!
Best Regards
Bellerophon
Speedbird 2, cleared take-off 31L.
You call 3-2-1 Now , start your stopwatch, pre-set to countdown from 58 seconds, and slam the throttles fully forward till they hit the stops. Four RR Olympus engines start to spool up to full power and four reheats kick in, together producing 156,000 lbs of thrust, but at a total fuel flow of 27,000 US gallons per hour. A touch of left rudder initially to keep straight, as the #4 engine limiter is limiting the engine to 88% until 60 kts when it will release it to full power. The F/O calls Airspeed building, 100 kts, V 1 , and then, at 195 kts, Rotate . You smoothly rotate the aircraft, lift-off occurs at around 10\xb0 and 215 kts. You hear a call of V 2 but you keep rotating to 13.5\xb0 and then hold that attitude, letting the aircraft accelerate.
The F/O calls Positive Climb and you call for the Gear Up . On passing 20 feet radio height, and having checked the aircraft attitude, airspeed and rate of climb are all satisfactory, the F/O calls Turn and you slowly and smoothly roll on 25\xb0 left bank to commence the turn out over Jamaica bay. Some knowledgeable passengers will have requested window seats on the left side of the aircraft at check-in, and are now being rewarded with a very close look at the waters of Jamaica Bay going by very fast! As you accelerate through 240 kts, the F/O calls 240 and you pitch up to 19\xb0 to maintain 250 kts and keep the left turn going to pass East of CRI.
54 seconds from the start of the take off roll you hear the F/O counting down 3-2-1 Noise whereupon the F/E cancel the re-heats and simultaneously throttles back to noise abatement power, around 96% as you pitch the nose down to 12\xb0 to maintain 250 kts. It is less than a minute from start of roll and already 435 US gallons of fuel have been used.
Speedbird 2, contact departure, so long.
Turning through heading 235\xb0M, the F/E quickly re-applies full dry power as you pitch up to 17\xb0 to maintain 250 kts, but simultaneously reduce the left bank to 7.5\xb0, in order to increase both the radius of turn (to stay on the optimum noise abatement track) and the rate of climb (less bank, higher RoC).
On climbing through 2,500 ft you increase the bank angle back to 25\xb0 left bank and as you approach the 253\xb0 radial JFK, you hear 3-2-1 Noise from the F/O for the second time. The F/E actions the second noise-abatement power cut back, you pitch down to 12\xb0 and, if not in cloud, sneak a quick peek out of your left hand window, looking for the car park by the Marine Parkway bridge, as you would ideally like to pass right over the car park, if possible, as we tip-toe quietly across the Rockaway Beaches, in order to minimise the noise impact on the residents.
Keep the left turn going and intercept the 176\xb0 radial outbound from CRI, and at 5 miles DME from CRI, call for the F/E to slowly re-apply full climb power as you pitch up to maintain 250 kts. We are still in US territorial airspace, below 10,000 ft, and subject to statutory speed control.
Speedbird 2, present position direct to SHIPP, climb FL230, no speed control.
The F/O selects direct SHIPP in the INS and tells you that she has selected that information into your Flight Director. Having checked that the gear lever is at neutral, you call for the Nose Up , and then the Visor Up . Flight deck noise levels drop dramatically as the Visor locks up. Now more than 12 miles away from the coast, we are clear of US speed control requirements so lower the attitude to 9\xb0, accelerate to V MO , currently 400 kts, and ask for the After Take Off Checks.
Speedbird 2, present position direct to LINND, climb in the block FL550-600, accelerate Mach 2.0
Call for the Climb Checklist at Mach 0.7, which will trigger the F/E to start pumping fuel rearwards to move the CG aft, then when he's done that, straight into the Transonic Checklist . Maintain 400 kts IAS, and around 24,500 ft, at M0.93, ask for the re-heats back on, in pairs, and raise the nose by 3\xb0 to maintain 400 kts as they kick in.
Precise, smooth flying is required through the high drag transonic region, as the mach meter creeps up towards Mach 1. A sudden flicker on the VSI and Altimeter confirms that the shock wave has just passed over the static ports, and the aircraft is now supersonic. A quick glance at the elapsed time indicator shows that you\x92ve been hand flying for just over 9 minutes since the start of the take off roll.
Another fun start to a day in the office, and to think we got paid for doing it!
Best Regards
Bellerophon
21st Dec 2010, 20:20
permalink Post: 933
Here are the graphs that
CliveL
was referring to.
The Mach trim control law
The aircraft response to a double engine surge
Split into two halves (longitudinal and lateral response)
Note the almost immediate rudder response, long before the engine N2 rpm starts to wind down. I'll have something to say about that in a separate post....
CJ
The Mach trim control law
The aircraft response to a double engine surge
Split into two halves (longitudinal and lateral response)
Note the almost immediate rudder response, long before the engine N2 rpm starts to wind down. I'll have something to say about that in a separate post....
CJ