Posts about: "Shannon" [Posts: 15 Page: 1 of 1]ΒΆ

M2dude
August 22, 2010, 00:47:00 GMT
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Post: 5884837
Biggles78
Am I right or even slightly so in thinking that cruise climb and cruise descent was the flight and there was minimal actual level cruise in the "pond" crossing?
You are right on the button. Under NORMAL circumstances, Concorde never flew supersonically in level flight. You would always follow the Vmo bug on the ASI during the supersonic climb. (The ASI pointer actually nudged into the bug; it was a beautiful design). Initially this would be at a constant Vc of 400 kts, the 400 KT segment then went off towards 530 KTS as you climbed. You then 'stuck' to 530 knots until a fraction over 50,000', when 530 KTS became Mach 2. You would then continue the climb at between Mach 2 and around Mach 2.02, depending on the temperature of the day. (the colder the temperature, the faster you tended to fly). There was an extremely complex AFCS mode for the supersonic climb, that I promise to cover in anaother post.
So yes, on the whole, TOC did equal TOD.
The 'subsonic climb' wasn't quite as you thought; you'd normally subsonic climb to FL280, staying there (at Mach 0.95) until the acceleration point. Mach 0.95 was 'subsonic cruise'. But you were on the right track.
Oh, and NOPE, they never boomed us either
Nick Thomas
If an engine had a fire or an explosive failure; it would seem on the face of it that the adjacent engine could easily be affected. As everything on Concorde has a sound technical reason. I have been wondering what that reason or reasons was? and also if there was any inbuilt dividing protection between engines on the same wing?
Keeping the powerplants as separate as possible was a major design headache, but generally they were just that; there was a titanium centre wall between the two engines and a really substantial heatshield above the engine also, to protect the wing above. To give you an idea how all this worked in practice, in 1980 G-BOAF, flying at Mach 2 between JFK and LHR had a major failure of one of the engines, caused by a defective material ingot used in the forging of one of the 1st stage LP compressor blades; which was subsequently shed. (The analysis done by Rolls Royce ensured that no such incident ever happened again in the life of Concorde). The resulting mayhem terminated in a large amount of engine debris flying around, and a titanium fire burning in the engine bay also. The aircraft however decelerated and landed at Shannon safely. On inspection, although there was extensive damage found in the engine bay, the adjacent engine was completely unmarked, protected by the titanium centre wall, and more importantly, when the heat shield werer removed, the wing was found to be completely undamaged!
The only problem you ever had with the dual nacelle arrangement was if you had an engine surge above Mach 1.6 (These were relatively rare, but could happen with an engine or intake control system malfuntion). If one engine surged, the other would surge in sympathy, because of the shock system being expelled from one intake severely distorting the airflow into it's neighbour. These surges were loud, quite scary (to the crew that is, most passengers never noticed much), but in themselves did no damage at all. Delicate movement of the throttles (employed during the subsequent surge drill) would invariably restore peace and harmony again to all. (The intake on Concorde was self-starting, so no manual movement of the intake variable surfaces should be needed in this event). After this was over, normal flying was resumed again As I said before, these events were relatively rare, but when they did occur, they would be dealt with smartly and professionally; the engine and intake structure being undamaged. (Post surge inspetion checks were always carried out on the ground after an event, on both engine and intake, but nothing much was EVER found).
Would I also be right to assume that the max power delivered by the engines would reduce at altitude, thus even if the engines were run at near to available max power at high altitude it would be no way near the max power at lower levels?
The reduction of fuel flow as you climbed was quite interesting. Although the throttles would be 'at the wall' (dry power remember), the electronic control system was constantly winding fuel off as a function of Static Air Temperature, as well as falling Total Pressure. The system was always 'tweaking' as you climbed, and you only used as much fuel as you really needed to stay at Mach 2. There were various ratings that would also be manually selected at various phases of flight; each rating change 'detuned' the engine slightly, so yes, you did not run the engine when flying fast at anywhere near the levels you did at lower speeds/altitudes. The engine final ratings were changed from 'Climb' to 'Cruise' manually at FL 500, just as you hit Mach 2).

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galaxy flyer
August 22, 2010, 01:11:00 GMT
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Post: 5884860
M2Dude

Yes, 4,000 hours in Lockheed's contribution to wide-body cargo planes. The marvel in all of these planes from the '60s that they were designed by men who began their engineering careers during WW II, used slide rules and tested nearly everything in the sky. I asked a Lockheed engineer (a Canadian from the Avro Arrow program which throw off a number of engineers to the US) how many guys did the actual design work--his answer was something like 300. With GE engines, the Galaxy is finally reaching its potential. A proper plane--it has a Flight Engineer.

My one contact with the Concorde was when I flew a US corporate jet in the mid-80s for a British-American company (industrial gases, you can guess the rest) whose MD was an American who worked in London. During the summer, like clockwork, he worked in London on the Friday mornings, take the mid-day Concorde to JFK. Customs would meet him AT THE GATE, clear him and turn him over to us for the short flight to Martha's Vineyard. His wife could recognize the plane, meet us at the airport at noon for lunch. On Monday, the return trip would unfurl in reverse. NOT one bit of that story can happen today, I cannot imagine US Border officials doing such a thing.

I did hear that a Concorde did once need a engine change in Dulles.

One more question, could the Concorde lose pressurization, descend to some low level (FL180 or below, perhaps FL100) and make it to scheduled destination or would a divert to Shannon or Gander be required? What was a low level cruise speed?

I was recently at Duxford and did tour the Concorde there, amazing how small the cabin was--DC-9-like.

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M2dude
August 22, 2010, 11:29:00 GMT
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Post: 5885435
Galaxy Flyer
One more question, could the Concorde lose pressurization, descend to some low level (FL180 or below, perhaps FL100) and make it to scheduled destination or would a divert to Shannon or Gander be required? What was a low level cruise speed?
We never had a case of lost pressurisation, ever. The cabin windows had dual laminated panes; an inner pressure pane and an outer thermal pane. We had dual systems that kept the cabin at a max diff' of 10.7 PSI, the engine bleeds pushing about 200lb of air per minute into the cabin. This allowed you to fly the cabin at an altitude of around a 6000' maximum only, right up to TOD. If you HAD to fly subsonically, the ideal was Mach 0.95 at FL290. (Subsonically the aircraft had similar range to normal, but took well over twice as long of course). If however you had to shut down an engine, your range deteriorated quite dramatically, and a diversion was usually sought.

It's great that Bellerophon is posting here again; we need a steely eyed Concorde pilot's input here (not just the boffins/nutters and nerds [that's me ]. To touch more on a couple of his valid points;
Fuel burn: The aircraft would naturally require less fuel as she became lighter and as a consequence gently climbed to maintain cruise Mach number, this is what the engine control system was doing all the time, even though the throttles were wide open it was 'tweaking'.. BUT, the decreasing IAS as you climbed, due of course to the reducing density, just like any other aircraft meant that drag was reducing too, so it was a combination of both of these factors, reducing weight and reducing drag.
Flying controls: It was a slightly weird but wonderful arrangement; pilots inputs would move a servo valve in the hydraulic relay jack, the jack would move in response and drive both a resolver AND mechanical linkages. The resolver ourput was sumed with the flying control position resolvers, and the error signal was fed into an autostab' computer, where it was summed with stabilisation demands (primarily axis rate and acceleration). The autostab computer would the directly drive the surface, and the reducing error signal would reduce the demand etc. While all this was going on, the mechanical linkages would slavishly follow, but as long as you were in FBW (what we used to call 'signalling') mode, these mechanical inputs were de-clutched at the PFCU, so did nothing at all. Only if there was an EXTREMELY unlikely failure of BOTH FBW channels would these inputs be clutched in and the flying control group (rudders, inner elevons or outer and mid' elevons) would then be in Mechanical signalling. The system redundancy was checked after engine start on every flight. But to reinforce what Bellerophon stated, there was no mechanical reversion here; without hydraulics you had nothing. Another aside here; the designers, being paranoid like all good designers (no offence Christiaan ) were worried what would happen if the controls would somehow jam up. A jammed mechanical flying control input run itself would have no effect on FBW operation whatsoever, due to spring boxes being fitted to the runs. A 'Mech Jam' light would be set, together with a separate red light and audio warning, but this was all. But to completely protect against the aircraft was fitted with a Safety Flight Computer (SFC) system. The idea was, if a control axis (pitch or roll only) jammed up, the captain could press down on a switch light set between the two halves of his control wheel, (at the centre of the 'W') and the Emergency Flight Controls would activate. Strain gauges at the front of the control wheel, two sets on each control column for pitch and roll axis, would input into an SFC that would covert the control force into an elevon demand. These commands were then fed into the autostab' computers, and hence directly into the controls. (A little like L-1011 CWS in a way). There was a little test button that was used to test this system, again after engine start. So although the controls were jammed, the aircraft could still be flown. (Never used in anger I'm pleased to report).
But there was a problem; if this system was inadvertantly used, the results could have been catastrophic, as the system was extremely sensitive indeed, and full elevon movement could be enabled with only moderate effort. Because of this hairy prospect some safeguards were obviously put in place. The first safeguard was an interlock in the autostab' engage logic; If the switchlight had been inadvertently selected beforehand (the light was green by the way) you would not be able to engage pitch or roll autostab's (both channels too) so you would not be going flying until that was fixed. The second safeguard was a little more subtle; A plastic, frangible cover was fitted over the switchlight, unless the captain pressed reasonably hard the cover would prevent the switchlight from being pressed. At least that was the theory, in practice this little bit of plastic could be a pain in the ass . It was carefully fashioned, and I seem to remember BAe charging the airlines a few hundred pounds each for these things. If some wally fitted the cover upside down (and unless you were careful it was easy to do) THE THING WOULD NOT BREAK!! I remember at Fairford in 1976, G-BOAD was on pre-delivery flight testing, and the late great test pilot John Cochrane was doing a test of the system. The cover on this occasion HAD been fitted upside down, and of course he could not plunge his thumb through it and engage the EFC button. After trying everything, in the end he removed a shoe, took out his pen, and smashed the plastic cover until it broke. (It's OK, the autopilot was engaged at the time). Unfortunately, his combined shoe/pen emergency device also wrecked the switchlight as well, so the system still could not engage. (There was only a switchlight on the captain's side). After he landed and he confronted us all with his dilemma, he was shaking; not with rage but with laughter. (This was the great John Cochrane, sometimes the dour Scotsman but he was always able to see the lighter side). After that event, careful instructions were issued regarding the fit of the cover, and it was modified and made a little more frangible.

Last edited by M2dude; 22nd August 2010 at 23:02 . Reason: will engineers ever learn to spell?

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Brit312
September 03, 2010, 18:24:00 GMT
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Post: 5911811
Biggles,

The Braniff crews [ I think it was 5 sets of crew] were trained for Concorde with some of crews trained in France whilst the others were trained in the UK. Flying training was done using an Air France Concorde
F-BVFA with flying being at Shannon initially but when they ran out of fuel it was moved to Montpellier. As their operation was to be subsonic they were only trained to operate the aircraft subsonically, but they were given a supersonic trans Atlantic trip as an observer.

ChristiaanJ

If I remember correctly ground effect tended to force the aircraft nose down, so requiring the pilots to pull back on the stick as if they were flaring ,but in fact what they were doing was as you say maintaining the pitch attitude constant. I have to say that in the early days the landing could be a bit of a hit or miss affair with some being perfect and some less so. The crews were originally taught to pull the power off in one stroke at about 15ft, but later they used to bleed it off and in my opinion this improved the landings greatly.

The problem with landing Concorde was when it got into ground effect if you let the nose drop you lost a lot of lift and arrived somewhat heavily. However if you pulled too hard you could raise the nose too much and suffer a big loss of speed causing a subsequent un-attractive landing, and you could also touch the tail wheel. This touch would be noticed by the ground engineer after landing as a scuff mark on the tail gear tyres. Therefore your friendly F/E on his external check prior to departure would always check the tail wheel tyres for scuff marks and if there were any you could inform the engineers at the other end of the trip that they were there prior to you taking the aircraft, and they would have to go and find another crew to blame


At touch down the pilots eye height was similar to that of a 747 pilot at touch down. Below 800ft when the aircraft had slowed down to landing speed the pitch attitude was such that the F/E could not see the runway ahead






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M2dude
October 16, 2010, 01:43:00 GMT
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Post: 5997965
SNN is Shannon my friend.
Oh, and you may want to copy questions again; there is an extra one I've added.
Best Regards

Dude

Last edited by M2dude; 16th October 2010 at 08:50 .

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OAB11D
October 16, 2010, 13:47:00 GMT
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Post: 5998740
questions

Humble SLF here, hope it is ok to have a stab at the questions, mods please feel free to delete if necessary.

1) How many Concorde airframes were built?

22, 20 that flew and 2 test frames

2) As far as the British constructed aircraft went, name the destinations that were served?. Regular flight numbers only, excludes charters etc.

New York, Washington, Miami, Barbados, Toronto, Bahrain and Singapore, no British registered aircraft ever operated to or form Dallas, should not forget BAs most popular destination of all time-London


3) What was the departure time for the ORIGINAL morning LHR-JFK Concorde services? (Not called the BA001 then either).

0930-Local

4) Further to question 3 above, what WERE the original flight numbers for the BA001 and BA003? (The morning and evening LHR-JFK services?).

193 & 195 respectiveley

5) There were no less than FORTY SIX fuel pumps on Concorde. What was the breakdown for these? (Clue; don't forget the scavange pump ).

Pass


6) What was the only development airframe to have a TOTALLY unique shape?

101, G-AXDN


7) This one is particularly aimed at ChristiaanJ. What was the total number of gyros on the aircraft?

pass


8) How many wheel brakes?

8


9) What Mach number was automatic engine variable intake control enabled?

1.3


10) Above each bank of engine instruments were three lights, a blue, a green and an amber. What did they each signify?

Not sure here, best guess -green was part of the take-off moniter -red failure-blue reverse

11) At what airfied were the first BA crew base training details held?

Prestwick, shannon, and one in France


12) What LHR runways did Concorde use for landing and take-off? (Trick question, not as obvious as it might seem).

28L , 28R, 27L, 27R, 9L, 9R 10L 10R, 23

13) What operator had serious plans to operate Concorde from SNN to JFK in the early 1980's?

Fed-ex


14) What development aircraft did not exceed Mach 2 until fifteen months after her maiden flight?

214? G-BFKW

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M2dude
October 22, 2010, 08:26:00 GMT
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Post: 6010620
Devil Ze Concorde Quiz Mk 2 (Or is it Mach 2?).... Ze Answers

OK guys, here are the answers. If you disagree about any of them then fire away, the old memory certainly 'aint perfect.
1) How many Concorde airframes were built?
As many of you have guessed, there were 22: The 14 production airframes, the 2 production series development aircraft (201 & 202), the 2 pre-production airframes (101 & 102) and the 2 prototypes 001 & 002. PLUS, the major fatigue test specimen at the RAE Farnborough and the static test specimen at CEAT in Toulouse. The CEAT tests actually tested the wing to destruction; I seem to remember it was something like a 200% overload before the wing failed at the root. And great but rather sad pictures VOLUME , never seen these before.
2) As far as the British constructed aircraft went, name the destinations that were served?. Regular flight numbers only, excludes charters etc.
OK, from MY memory , we have: London LHR (duhhh!!), Bahrein BAH, Singapore SIN, New York JFK, Washington IAD, Dallas DFW, Miami MIA, Toronto YYZ, Barbados BGI, and Riyadh RUH. As well as charters being ommited, so are some of the special 'surprise' shuttle appearances that Concorde would make, substituting a subsonic to and from destinations such as Manchester and Edinburgh.
3) What was the departure time for the ORIGINAL morning LHR-JFK Concorde services? (Not called the BA001 then either).
11:15
4) Further to question 3 above, what WERE the original flight numbers for the BA001 and BA003? (The morning and evening LHR-JFK services?).
The BA193 and BA 195.
5) There were no less than FORTY SIX fuel pumps on Concorde. What was the breakdown for these? (Clue; don't forget the scavenge pump ).
OK, there were 12 engine feed pumps (3 per engine) 8 main transfer tank pumps (2 each for the transfer tanks 5, 6, 7 & 8), 4 'A' tank pumps (2 each for 5A & 7A), 8 trim-transfer tank pumps (2 electric pumps each for tanks 9, 10 & 11 PLUS 2 hydraulically driven pumps for tank 9), 4 electric engine start pumps (there was a single electric start pump per engine that delivered fuel to it's own dedicated start atomiser in the combustion chamber. The pump automatically ran when the engine HP valve was set to OPEN and would continue running for 30 seconds after the DEBOW switch was returned to the 'normal' position), 4 engine first stage pumps (a single mechanically driven pump per engine), 4 second stage pumps (a single pneumatically driven pump, sometimes termed 'the turbopump, per engine. This would cut out at around 20,000'), our scavenge tank pump (triggered automatically when there was 7 US gallons in the tank; pumping it back into tank 2. This pump was identical to an 'A' tank transfer pump), and FINALLY, a single de-air pump for tank 10. The pump would drive the fuel through a mesh, removing air bubbles from the fuel. Tank 11 used the L/H trim pump for de-air (similar principle)and would be switched on during take-off. This is why the tank 5 trim inlet valve being set to over-ride OPEN would result in the tank being highly pressurised in the case of the Gonesse disaster; the pump would obviously pressurise the L/H trim gallery and any tank on that side with an open inlet valve!!!
6) What was the only development airframe to have a TOTALLY unique shape?
G-AXDN, aircraft 101. (A production wing, fuselage, droop nose and intakes, but with the short tail section and secondary nozzles of the prototypes.
7) This one is particularly aimed at ChristiaanJ. What was the total number of gyros on the aircraft?
Ready ChristiaanJ? There were 18....Yes, the single SFENA standby horizon, 9 INS gyros (one per X,Y and Z platform in each of the 3 INUs), 8 autostab' rate gyros (one per axis for each of the 2 autostab' computers PLUS a monitor gyro for the pitch axis). The radar by the way used attitude signals from the INS.
8) How many wheel brakes?
9. One per main wheel plus the single 'in flight braking' nose wheel brake.
9) What Mach number was automatic engine variable intake control enabled?
Mach 0.7!!! Between this and Mach 1.26 the intake surfaces were positioned as a function of engine N1 if the engine was shut down for any reason. (Otherwise of course the intake surfaces were fully up). You needed a sub idle N1 of 57% and below for all this to happen, and it was to assist relight performance and reduce buffet. Between Mach 1.26 and 1.32 the ramps were driven down slightly to about 5%, full supersonic scheduling itself commencing at Mach 1.32.
10) Above each bank of engine instruments were three lights, a blue, a green and an amber. What did they each signify?
Already brilliantly answered by Brit312 (as well as the FSLabs diagram). Yep, Geen GO, T/O monitor armed, fuel flow and P7 at or above datum, A/C on ground, reverse not selected and CON light not on. Amber CON (Reheat selected and not detected, N1 OK or reverse selected and primary nozzle (Aj) not at minimum. Blue REV; steady buckets at reverse, flashing buckets in transit.
11) At what airfield were the first BA crew base training details held?
Fairford, followed by Brize Norton, and then a host of airfields from Prestwick and Shannon to Chateauroux.
12) What LHR runways did Concorde use for landing and take-off? (Trick question, not as obvious as it might seem).
OK, probably no surprises now:
Landing - 27L & R, 9L & R (prior to LHR mag' deviation update were 28L & R & 10L & R) together with 23/05.
Take off - 27L (28L), 9R (10R) and 9L. (10L never happened as take offs on this runway only occurred in 2003).
13) What operator had serious plans to operate Concorde from SNN to JFK in the early 1980's?
It was FedEx, they planned to operate two stripped out aircraft, leased from BA, between Shannon and JFK as high value parcel carriers. The idea was that parcels would be flown in from all over Europe by small FedEx feeder aircraft and the parcels transferred to Concorde which would then speed on to JFK in around 2 1/2 hours. It never happened because of a combination of economics appraisal by FedEx and BA deciding that it could would not release the aircraft anyway.
14) What development aircraft did not exceed Mach 2 until fifteen months after her maiden flight?
A/C 101, G-AXDN first flew on 17th December 1971 with FIXED INTAKES!! (101 was going to be the launch vehicle for the new digital intake control system, but the 'boxes' were still being designed). This placed an operating limit of Mach 1.5 on the aircraft, limiting her ability with such a restricted flight envelope. She returned to Filton in late 1972 for installation of the system, as well as the new Olympus 593-602 engine. (The engine, very similar to the production Mk 610 version, used a quite revolutionary annular combustion chamber, and eliminated at a stroke the thick smoke exhaust that had up to then been Concorde's unwanted visual signiture). The aircraft flew more or less smokeless on 15 March 1973, achieving Mach 2 soon afterwards. As ChristiaanJ pointed out, the British prototype 002 had a similar gap, actually significantly higher, of 19 months. (The French aircraft 001 had an even longer gap of some 20 months).

I hope you guys had fun with this one, regards to all

Dude

Last edited by M2dude; 22nd October 2010 at 10:21 . Reason: oops, misssed out question 2

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Brit312
October 22, 2010, 14:44:00 GMT
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Post: 6011345
Fairford, followed by Brize Norton, and then a host of airfields from Prestwick and Shannon to Chateauroux
In 1987 we also used Machrihanish because they were digging up the end of Prestwicks runway which made it too short for touch and go

In1998 we also used Porto as I think Chateauroux asked us to leave after too many noise complaints

Before we started base flying at Brize Norton there was a lot of negative opinion about it due to possible noise. The first day of training the airport was saturated with noise complaints, however what the local population did not know was that the Concorde had gone U/S and did not fly on that day. They could not see due to cloud cover but what they were complaining about were the RAF VC-10 in the circuit , and these aircraft had been training there for months with no complaints.

Shannon was always considered too risky for Concorde to base it self at for Base training, however in 1998 when things in N.Ireland had settled down a bit we did base a Concorde for a few days in Shannon for base training.

If I remember correctly during all the flight testing program at Fairford, BAC built a lay-by on the main road so that the public could watch the aircraft come and go free of charge. Apparently some bright spark bought himself a white coat and a roll of parking tickets and started charging people for parking. Now that is what you call free enterprise

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M2dude
October 23, 2010, 11:22:00 GMT
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Post: 6012930
Brit312
In 1987 we also used Machrihanish because they were digging up the end of Prestwicks runway which made it too short for touch and go
I was up at Prestwick in 1988. and I remember that several details were carried out doing touch and goes at Machrihanish also, when the late GREAT John Cook was running things flight training wise.
In1998 we also used Porto as I think Chateauroux asked us to leave after too many noise complaints
Concorde noisy? What WERE they talking about
Before we started base flying at Brize Norton there was a lot of negative opinion about it due to possible noise. The first day of training the airport was saturated with noise complaints, however what the local population did not know was that the Concorde had gone U/S and did not fly on that day. They could not see due to cloud cover but what they were complaining about were the RAF VC-10 in the circuit , and these aircraft had been training there for months with no complaints.
Oh this was typical; so many of, shall we say, the less sensible members of our species, would blame Concorde for absolutely ANYTHING, whether sh was flying or not
Shannon was always considered too risky for Concorde to base it self at for Base training, however in 1998 when things in N.Ireland had settled down a bit we did base a Concorde for a few days in Shannon for base training.
Actually a few training sesions were carried out there in the mid to late 1990's, before the norm, became Chateuroux. I remember 'Dirty Nellies' fondly, as anyone who is familiar with SNN will understand.
If I remember correctly during all the flight testing program at Fairford, BAC built a lay-by on the main road so that the public could watch the aircraft come and go free of charge.
It was not so much as a lay by as a real car park, right on the edge of the runway. Whenever the aeoroplane was going to fly, word got around and the car park filled up quickly. Right up to when the Fairford Flight Test Centre was closed in early 1977, the car park was always filled to overflowing.

Thanks for coming up with the additional flight training airfields Brit312, my poor old memory is fading... FAST......

Dude

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M2dude
November 07, 2010, 00:34:00 GMT
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Post: 6044389
Oh darn it Feathers, if you insist (LOL).
First of all, what is rotating stall? All gas turbine engines are prone to this to some degree or another, the Olympus was particularly prone (so we discovered to our cost). What happens is that extremely LOW figures of N2, small cells of stalled air rotate around the anulus of the early stages of the HP compressor (at approximately half the rotational rpm), resulting in parts of the airflow becoming choked and highly distorted. This often results in the combustion process being disturbed to the extent that combustion instead of occuring in the combustion chamber, occurs in the turbine itself. This of course results in massive overheating of the turbine blades and stators (and is what is suspected occured in the #2 engine on G-BOAA in 1991.
To prevent running in rotating stall, the Olympus automatic fuel start schedule would accelerate the engine quickly to around 67% N2 before dropping back to the normal idle figure of around 65% N2. (The stall clearance N2 figure was ambient temperature dependant, the higher the temperature the higher the N2 that was required and hence scheduled by the automatics).
What had happened on G-BOAA was an engine starting/accelerating problem, where the N2 ran at a sub-idle of around 40% N2 for several minutes. This was enough for the malignant effects of rotating stall to take hold, and the resulting turbine blade failure over the Atlantic the following day. In all fairness to everyone involved, none of us, including Rolls Royce realised just how potentially serious this phenonomen was, and salutary lessons were learned by one and all. (The following year Air France had a similar failure; their first and last also).
I flew out to Shannon on a BAC 1-11, that was sent to fly the Concorde passengers back to London. As I and my colleague were coming down the ventral door steps of the 1-11, a chirpy Aer Lingus engineer asks 'have you guys come to fix the broken engine?, there are bits of it lying in the jet pipe'. Now up to now, from the information we'd been given in London, we thought that we were going to be looking at either an intake or engine induced surge, a few systems checks and boroscope inspections and we'd all be on our way, so we naturally thought the Aer Lingus guy was joking. He was most certainly was not; as you looked into the jetpipe (through the secondary nozzle buckets) you could see a large quantity of metal debris, accompanied by a strong smell of burnt oil. I remember this day well, it was the day that the first Gulf war ended; how ironic.
The aircraft departed on three engines, flown by a management crew late the following day, my colleague and I returned to London by Aer Lingus one day later. (No passengers whatsoever are permitted on ferry flights, even expendable ones like me).

Dude

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dixi188
December 11, 2010, 19:04:00 GMT
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Post: 6116565
A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp.
I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.

A double engine change ensued.

Question, how fast was the ramp going if the A/C was at Mach 2?

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ChristiaanJ
December 11, 2010, 19:59:00 GMT
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Post: 6116631
Originally Posted by dixi188
A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp.
I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.
Maybe M2dude remembers the occasion?

First time that happened was on prototype 001 in the very early days, when an engine "spit out" the entire ramp (there's a photo in Trubshaw's book).
The ramps and actuators were 'beefed up' considerably afterwards... I didn't know an in-service aircraft had suffered a similar mishap.

Question, how fast was the ramp going if the A/C was at Mach 2?
Good question.... not being an "engine man" I've always been amazed how a nice steady Mach 2 flow, slowed down to Mach 0.5 at the engine inlet, is capable of totally choking off and even reversing itself in less than a second.... no wonder it's usually accompanied by a big bang!

CJ

PS I have no record of any of the British development aircraft ever having lost a ramp, notwithstanding the number of deliberate engine surges they went hrough. But then maybe I wasn't told....

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M2dude
December 11, 2010, 21:17:00 GMT
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Post: 6116745
Talking Them darn intakes

Hi Guys, quite a few little points here, so here's my angle(s):
Pedalz
were the intake ramps in front of the engines ever known for problems? Especially during supersonic cruise where the airflow through the compressors and position of the ramps was determined by an exacting science which could turn into quite a situation if disturbed. Which hydraulic system actuated these ramps?
Ooo yes. The biggest problems we ever had associated with the ramps themselves were wear in the seals at the sides of the forward ramp. Even a few thou' over the maximum allowable side gap was enough to make the intake unstable and susceptible to surging. (It is quite interesting that the rear ramp side gaps were not in the least bit critical, and if Concorde intake development had continued, the rear ramps were going to be deleted altogether). Other failure factors were control unit malfuntions, rapid sensor drift; all of these causing either ramp/spill door drift or runaway. Primary nozzle misbehaviour could also result in intake surges. Having said all that, the monitoring of the intake system was truly superb, and surface runaways, themselves quite rare, would usually be picked up by the control system monitors causing either a lane switch or if that did not work, a total 'red light' failure with the surfaces frozen. No surge was treated as 'just one of those things', and much midnight oil was burned and hair pulled out (so that's what happened to mine ) to try and find the cause of the surge.
My friend EXWOK perfectly answered the intake hydraulics allocations.
Due to the shape of the leading edge and positioning of the intakes themselves, could it be possible that disturbed airflow from a problem ramp or donk could also effect it's outboard neighbour (if I'm right in presuming that only the inboard engine surging etc. could effect the outboard and not vice versa)?[/
EXWOK was right on the ball here as usual, in fact above Mach 1.6 an interactive surge was more or less guaranteed. The cause of interactive surge had nothing to do with the wing leading edge position, but to the radially generated distortion field coming out of the FRONT of the surging intake, severely distorting the adjascent intakes airflow. It mattered not if the originating surge was an inboard or an outboard intake, the other guy would always go also, above Mach 1.6.
You might want to take a look at 'When Intakes Go Wrong Part 1:
http://www.pprune.org/tech-log/42690...-thrust-5.html
and Parts 2 & 3:
http://www.pprune.org/tech-log/42690...-thrust-5.html
Not to mention Part 3:


dixi188
A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp. I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.
I can never recall this particular event happening with BA , certainly not as a result of a ramp failure. Although in the near 28 years of operation we had quite a few SNN diversions, none that I can ever recall were as the result of a ramp structural failure. The two major SNN diversions that I can recall were G-BOAF in the early 80s when an LP1 blade failed and resulted in a totally wrecked engine (although a completely contained failure) and G-BOAA in 1991, with another wrecked engine due to running in rotating stall. (Both of these events were covered previously in our thread). ChristiaanJ has mentioned quite rightly the event with A/C 001 spitting a ramp out, and Air France had a ramp failure going into JFK. (Covered previously in our thread, due to certain 'human foul ups'). I am not sure, but I think that this one in JFK DID require a double engine change in JFK. (Usually from SNN a BA aircraft would be 3 engine ferried back to LHR).

ChristiaanJ
PS I have no record of any of the British development aircraft ever having lost a ramp, notwithstanding the number of deliberate engine surges they went hrough. But then maybe I wasn't told....
Nope, you are quite right, no more French or British development aircraft ever suffered a ramp linkage failure again. The 001 ramp failure was a salutary lesson to the design team, and the intake assembly became tougher than old boots after that, nomatter WHAT you threw at it.


Due to the lateness of the hour (and me being up at 4 ), that will have to do for now guys.

Best regards to all
Dude

Last edited by M2dude; 12th December 2010 at 03:51 . Reason: Adding a bit and correcting another

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NineEighteen
June 13, 2015, 11:04:00 GMT
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Post: 9010123
Former Concorde Captain Keith Myers was one of my IR procedural instructors around 13yrs ago at Redhill. He had some fascinating stories about the early days of operations. Flying circuits at Shannon for example.

I recall a story about timing from break release to Supersonic, I think, from Shannon. Would 9 minutes be realistic? I forget the detail.

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dixi188
January 30, 2023, 11:56:00 GMT
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Post: 11376777
Someone I used to know,(TO), was a F/O on a Concorde that had a double engine failure mid Atlantic. One engine surged and coughed an inlet door out of the front and it went down the adjacent engine, The vibration was very high and both engines were shut down. The Mayday call to Shanwick was that they may not make Shannon. The reply was that they would alert the coastguard.
IIRC they restarted the engine with the lowest vibration and made it to Shannon.
I saw some photos of the engine that ate the door and the compressor was a mess.

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