Hi M2 Dude

Thanks very very much for your long reply and good explanation.:ok:

- So once we select the Engine schedule to mode Hi or F/O the Prim nozzle will
open wider causing the pressure at the Prim nozzle to drop and hence the
higher flow of the exhaust through the LP turbine = Higher N1 RPM.
Am I understand it correctly?

- According to your reply, the E schedule that will provide the most thrust is
the Low mode since the prim nozzle area will be the smallest among all of the
other mode which mean the highest pressure and temperature.
Am I understand it correctly? And if so why do BA [as far as I know] told the FE
to use Hi mode? Because the higher thrust can be obtain with higher N1?

- Also does the the Hi mode can deliver the higher N1 RPM, does that mean
the Engine control unit must deliver the higher fuelflow rate in order to keep
N2 run at the constant speed [higher N1 speed => higher pressure => more resistance
=> higher Fuelflow require to keep N2 run at constant speed]

Thanks for all of your reply!:ok:

Best Regards

Vortex :}

Roger

My appreciation for your complement. Anyone, yank or otherwise, who does not appreciate the long term and continuing world wide cooperation that is required for any project like Concorde or Apollo is simply being xenophobic. Today, Boeing has a large engineering bureau in Moscow, BMW has a design office in California.

Many of the engineers that worked on Apollo, 747 and, even, the C-5, were Canadian ex-pats fired from the Avro Arrow program shutdown. BTW, my nomination for least appreciated, least known but most ambitious aircraft design.

GF

Hi Landroger
But for those of us who were brought up as engineers in an analog world its not so scary.
remember by the late 60s chopper stabilised amps were well established and drift was much better controlled,
Is it an analog world out there? I think so :ok:
rod

Mr Vortex
More or less you are correct yes, but remember that schedule selection was more or less automatic. (E Flyover was armed prior to take-off, and E-MID during approach by the E/O, otherwise it was more or less a 'hands off' afair).
Oooo no, we are way adrift here I'm afraid. I'm trying not to get too 'heavy' with this explanation, and I've enclosed below the Rolls-Royce E Shedule diagram to try and help clarify everything. (I've edited out the exact equation figures in deference to Rolls-Royce). Where N1/√θ and N2/√θ is quoted, the term 'θ' related to T1 in degrees K/288. (288 deg's K being 15 deg's C). The hotter things are the higher the spool speed scheduled is, and visa-versa for lower temperatures. Only at a T1 of 15 deg's. C (Standard day temperature) does N/√θ equate to N. (But remamber that T1 is TOTAL temperature, that varies with Mach Number).
The use of E LOW above 220KIAS was not only strictly inhibited by the automatics, if you over-rode the automatics and 'hard selected' E LOW, the aircraft would fall out of the sky when reheat was cancelled at Mach 1.7. This was because the low N1/√θ scheduled by E LOW would now invoke an N2/√θ limit (The E3 Limiter in the diagram) and claw off fuel flow by the tonne.
The most efficient schedule for supersonic cruise was E HI which again would be automatically selected.
E-MID was automatically selected during afterburning operation, to minimise the chance of an N1 overspeed on cancellation of reheat. E-MID could also be selected by the E/O for noise abatement approach.
E Flyoverwas as we discussed before used for take-off flyover noise abatement as well as subsonic cruise if desired. (If Mach 1 was exceeded with E Flyover still selected, a yellow NOZZLE light illuminated and E HI would be automatically selected.
I sincerely hope that this blurb is not clear as mud, feel free to ask away.
Nope, that is the beauty of it all. Because of the part choking of the LP turbine section of the engine, the pressure changes due to Aj variation were felt exclusively by N1 and not N2. (Clever, these Rolls-Royce guys:)).
Regards

Dude :O
http://i1237.photobucket.com/albums/...chedules-1.jpg

Landroger
It always was a bit of a paradox; in terms of fuel price and environmental concerns, Concorde was about 5 years too late. But in ELECTRONICS terms she was 10 years too early. Bearing in mind that the first Intel 4004 was not even commercially available until 1971. When the decision was taken in late 1970 to 're-design' the analog air intake control system into a digital one, there was nothing to fall back on; a BAC custom guided missile processor (used I believe on both the Rapier and Sea Dart SAMs) had to be adapted. This processor was, as I've yawned on about before, comprised of multiple double sided PCBs completely stacked with TTL ICs. In spite of being a total antique and a dinasore (just like me :{) this thing was really cutting edge technology at the time, even using a 64 bit data word. The AICS as again I've yawned on about before, was the WORLD's first commercial airborne digital control sysstem, but the Concorde analog stuff in fact worked pretty well indeed.:ok:

Galaxy Flyer
As always GF you make your point really well. As far as Concorde went, the very few American (Branniff) pilots who flew her thought she was totally amazing, and the American BA engineers at JFK and IAD absolutely adored the aeroplane.
And back to your 'charriot', the C5 has been a staggeringly successful aeroplane in terms of US service. and is still thriving (big modernisation programme underway). Not bad for an aircraft that entered USAF service in 1969!!! :D
Regards

Dude :O

There are several answers.....

One thing to bear in mind is that a lot of the computing was closed-loop, usually with several loops within loops.
Such closed loops do not require a very high precision or very narrow tolerances inside the loop.
In the Concorde AFCS, most of such computing was based on the use of +/-1% components (resistors, capacitors...) which were stable enough over their lifetime, and the ubiquitous LM101A integrated operational amplifier, which had low enough offsets and drift for the application. Occasionally we had to use the LM108 op-amp (more precise) and +/-0.1% components.

And where the analogue electronic computing was totally inadequate, we used... electro-mechanical computing, using synchros, resolvers and servo loops.

As M2dude says "in ELECTRONICS terms she was 10 years too early".
He's right.
She dates from that precise era, where technology changed from discrete components through the very first integrated logic circuits to mass-produced 'airworthy' logic and analogue circuits, but where the micro-processor was still in the future.
She was really the culmination of the "classic" era, before "digital" took over.

I could waffle on for hours... but don't know where to start?
Ask your questions, to let me know what you want to know.

CJ

Galaxy Flyer
 

You're right there GF - the AVRoe Arrow is a complete mystery to me and I've heard of the Martin Baker single seat fighters and the Percival Peregrin! :hmm: :)

Roger.

Re the Avro Arrow....
I knew about the aircraft, but had to read up again about the history.

Sounds like TSR-2... very different aircraft, very different mission.... but same damn politicians....

CJ

Landroger
Off topic I know but just in case you have not seen last months issue of "The Aeroplane" there are a couple of articles on the Martin Baker single seater fighters.
Regards
Nick

M2, he mentioned ........ HE MENTIONED IT!! :{ :{ :{ :{

May I just chip in with what a wonderfull read, and to think this thread started with a simple?? question about the non existant APU 3 months ago!!

ps Landlady where are you?? we need another recollection please from the cabin to break up the technical stuff we may not fully understand but still find totally enthralling in a typical understated British way

ChristianJ and M2dude et al many thanks

Always love to hear stories like this....I am sure there are many more ! Cheers Christiaan ( and m2dude ) for such great information on our beloved icon....

Reg:

Ancient tale.

There's this SR-71 Blackbird stooging around Cuba on a top-secret mission, at FL500+ and Mach 2+.... when they get a call requesting them to change heading "because of traffic at your altitude".
Traffic at THEIR altitude ??
Anyway, they comply, and shortly, yes, there's an Air France Concorde out of Caracas (Air France flew there in the early days) slowly sailing across their flight path.

speedbirdconcorde,
You forgot the punchline....

Two guys in full pressure suits and bonedomes and all the rest....
Meeting close on a hundred people in shirt sleeves and summer dresses, sipping a glass of champagne, and just being served hors d'oeuvres.
Same speed, same altitude...

CJ

The accessibility of this thread to the 'man in the street', such as I, has confirmed to us what an astounding example of technical achievement Concorde is (not was!). (I'm going to stick my neck out and suggest that the cancellation of say the A380 would not engender a Pprune thread such as this).

Maybe a bit of a sentimental/daft question but may I ask what personal effects the discontinuation of Concorde had on the crews, the engineers and anyone 'hands on' with the aircraft?

The crews, the engineers and anyone 'hands on' with the aircraft would have known that they were involved with something very special. Moreso I detect from such posters that they seemed to have a relationship with the aircraft which went beyond the normal level of any professional working with interesting technology.

Were these people such well balanced types that they shrugged and took in their stride or was there seething but repressed anger? Was there a feeling of personal loss that such a thing would never happen again?

Haven't worded my question very well but I guess you can see what I'm getting at.

Cron.

Bugger...its past midnight and I'm still reading this thread !:) Time to hit the sheets before I find a Concorde vid to start watching lol

As others have said...brilliant thread and great to hear from all the Concorder's...

You are all responsible for my red-eyes in the morning :-) :ok:

Cron

If you watch some of the more recent Concorde programmes, such as "Concorde's Last Flight", you'll hear and see the reaction of the various people (including our very own Dude) from the BA side of things as they talk about their charge. The AF crews also have that same look on their faces in the few programmes I've seen them in.

I think that Concorde was a running love affair for a lot of people, especially for those that flew her, looked after the passengers and maintained her but the effect of a Concorde pass on just about anyone was noticeable. Every head turned and looked skyward, and kept looking even after the aircraft was out of sight. People who lived below the regular flight paths, who might have been expected to be upset by the noise, used to come outside and watch on every occasion. I've seen almost a whole street appear a few minutes before a departing Concorde that passed over Reading and be rewarded with a great view in brilliant sunshine.

Not many aircraft have that kind of following....:ok:

In my best 'Comic Book Guy' accent - Best Thread Ever......

We've heard from Engineers, Pilots, Designers, 'Ambassadors'.... How about ATC??? Are there any out there with their memories?? Was life slightly different when "No Speed Restriction" was offered and Concorde hit 400 kts+ instead of the mere mortals at +/- 300 kts?? Anything unusual in their handling on the way into LHR/JFK/IAD/BGI etc for sequencing?? Any general anecdotes to recollect?? Heathrow Director, are you out there? Your name sort of gives you away.....

Keep it up everybody!!

:ok:

PS - Was there ANYTHING on the Charger(ski) that was better or more advanced??

Thanks a lot M2Dude :ok::D

So if we select E Low at M>1.7 the N2 will ovespeed and hence higher fuelflow. Am I understand it right? Also, what E mode provide the
best config shape [lest sat suitable] that provide a con-di nozzle for
maximize thrust. [Not open to wide that exhaust can't reach M1 at the
throat of Prim nozzle].

And another quesrion here, the engine control unit use which parameter to control the thrsut. The EGT, or N2, or P7.

Thanks for yours reply.

Best Regards

Vortex :E

PS. thanks for your nice graph and fuel vent schematics too.

Feathers,

"If you watch some of the more recent Concorde programmes, such as "Concorde's Last Flight", you'll hear and see the reaction of the various people (including our very own Dude) from the BA side of things as they talk about their charge. The AF crews also have that same look on their faces in the few programmes I've seen them in."

Is this a different show from the discovery programme - if so, is it available on DVD or is it 'streamable' somewhere ?

cheers,

d

"Concorde's Last Flight" was shown a couple of months ago, on Channel 4 I think, but my memory may be playing up. No, it isn't, see here.

Concorde's Last Flight - Concorde's Last Flight - Channel 4

It's not on 4OD, so you will have to search other video sites and see if you can find it. Interesting, nothing really new and earth-shattering but some good things in it.

Cron
You sure touched a nerve or two there Cron. I can only speak for myself, but to me Concorde was more than a job, far more than just 30 years of my life, she was (and still is) an amazing and astoundingly beautiful aircraft. She was flown by dedicated, highly professional crews, some of which I still regard as some of my best friends. She carried an enormous variety of people, from the wealthy and famous to old Granny having a chance of a lifetime birthday treat. She epitomised what dedicated men (and women too) can achieve in the field of adversity when there is sufficient talent and dedication available to overcome massive political and technical hurdles. These guys and gals produced what is to me simply avaiation perfection. There is another aspect of Concorde's life that is seldom mentioned, that of live organ transportation across the Atlantic (in both directions I might add). I wonder just how many lives were saved by this marvelous use of speed. (The organs were transported in refrigerated containers and the speedy transport from the aeroplane was both slick and professional. I could go on.... but will give instead my personal feelings regarding this 'world without Concorde. The real TRUE story of why Concorde was withdrawn from service is for another time (this story has already been alluded to several times in this thread), but I am stilll filled with feelings of sadness, of guilt (was there really nothing any of 'us' could have done?) but mainly a deep feeling of anger and revulsion towards a small handfull of nasty little individuals that managed to destroy something so wonderful, so unique and so special for ALL the wrong reasons. I just hope these characters look back and are truly proud of themselves; this aviation 'crime' is right up there with the TSR-2 cancellation in my view.
But life goes on, and I had to spend the next few years learning all about those Boeing things. (You know I never realised that it was possible to fly WELL BELOW the speed of sound ;)).

BN2A
errrr nope. :E
Regards

Dude :O

Mr Vortex
Not quite; remember that the N1s and N2s in the E SCHEDULE graph are non-dimentional. ie. they vary with temperature. As the temperature rises (with increasing Mach Number) the scheduled spool speeds increase. What really happens (I did not explain it correctly first time) is that the much lower N1 demanded by the use of E LOW at high speed results in a much further closed primary nozzle than normal, pushing up TET (and EGT) and we run hard into the EGT limiter, which claws fuel flow off, to the extent that the ramps and spill doors come down to their preset limits, almost as if there is a flame-out. The net result is a huge reduction in thrust. The condi was formed as the primary nozzle naturally took up a near fully open position in supersonic cruise and the wide open secondary nozzle buckets completed the picture. The schedule used here was E HIGH. I've noticed a couple of errors on the graph, the main one being that E HIGH is used with reheat off but with Vc > 220 KIAS
Apart from being set as a variable limit, EGT normally played no role in the control loops (there were 2 loops, the 'governor' and 'positioner' loops). P7 played no part whatsoever in any case, the main variables were; N2, throttle valve position, throttle transmitter position, T1, total pressure and static temperature..

Feathers McGraw
Oh nooooo... I've been outed :}
Best regards

Dude :O

I have just come back from the pub so am being more open than normal. So I have to come out of the closet to admit that Concorde is the only inanimate object that I find "so sexy". I also think that most people that have contributed to this thread would agree with me.
Regards
Nick

M2 Dude

Back in August of 1997 I had the privilege of a ride in G-BOAC out of CYYZ on a flight to now where ie east of JFK up to FL550 Mach 2.0 etc.
It was back in a gentler day with a visit to the flight deck and I can still remember it all is if it was yesterday. As you can tell by web name I am industry and I really appreciated the short time I had in the Flight Deck. Unfortuneatly I was one of 99 that day so I did not get a chance to ask all the questions but the fuel system and fuel pump mini lecture from the flight engineer was stunning.
Please accept my sincere thank you and to Christian as well.
Like the Avro Arrow the TSR-2 the Concorde will live long in our minds.
One last comment many years ago we were number 2 on 09R in LHR and Concorde takes off in front of us. We were in an L-1011 that day and it shook as if a metal saw was trying to cut us in two. The Flight Service Director came running in white as a ghost and his first words were "What the #@&*" was that.........................
Please keep writing your story and if I ever run across you on the other side of the "pond" the bitter is on me

I remember once decending into JFK, still at about M1.7ish on the 001 and the 002 was climbing out having just accelerated. Through disruption to schedules (this would not usually happen) the AF pair were in the same state (one in, one out, both supersonic). I asked the controller (I *think* it was NY centre) if that was the first time he'd ever had four supersonic airliners, simultaneously, on his watch - the reply was effusive and summed up the really positive reaction that aeroplane engendered in people working with it in any field...

To the ATC question, one experience. I was flying a Falcon 10 into KIAD one afternoon, level in the mid-teens, indicated 300-ish, when the ATCO vectored us off the airway for overtaking traffic. Now, in 1980, the DA-10 was considered pretty hot stuff for biz jets. We asked for an increase in speed and offered 400 KIAS or better. We took the vector, to watch the Speedbird speed by. As magnificent as pictures are, in flight a couple of miles away it is stunning.

GF

a330pilotcanada
I'm so glad that the guys on Alpha Charlie looked after you so well on that flight. Meeting fellow aviators was always most pleasurable for my 'flying chums' and they's always wax lyrical with absolute pride. I can also only apologise on behalf of the enrire fleet for the underwear replacement that your Flight Service Director; the aeroplane DID look stunning from that close I know. :D
If the beers are on you my friend that will be great (but you can #make mine a Bud' if that's ok :ok:
Best Regards

Dude :O

In 2000 I was on my way to Helsinki in a Finnair A321 at Heathrow taxying out towards 28R when looking out of the windows we realised that a Concorde was passing to the left of us. Just at that moment the ceiling screens folded down and the forward facing camera powered up, showing us the whole of the Concorde as it turned onto the runway and spooled up. The whole of the fuselage of our 'bus was rattling away, and then as the noise decreased we were cleared to line up ourselves and the screens showed rapidly receding reheat flames through a cloud of exhaust smoke. Despite being cleared to take off immediately, we were naturally left well behind, I could just see the Concorde climbing out to the west as we turned north and then east to head off across to the North Sea.

No prizes for guessing which flight I would have preferred to be on....:(

Thanks very much M2Dude for your answer. :D

I'm wonder if all 4 Olympus 593 all died in flight and unable to restart. Is it
possible to be able to land at the nearest airport?
I've heard some of the double delta fighter like saab 35 Draken suggested that
if engine was died inflight, ejection was recommend since it isn't possible to land
[maybe due to the enormous of drag create while aircraft approaching the
runway]. So if i'm wrong please correct me. I'm no expert in saab draken.:sad:

Thanks for all of yours reply. :ok:

Best regards

Vortex :E

Many thanks to Dude, Christiaan and all the others for a wonderful thread.

Yesterday, being in New York, I headed off to the Intrepid museum on the Hudson to see BOAD - I spent ages wandering around marvelling at this beautiful machine, people must have thought I was crazy ignoring the other exhibits!

Unfortunately, never had the chance to fly in Concorde, but did go out to see 002 when she flew into Melbourne in 1972 (I can still remember the experience in fine detail, even now - I must sort through my photos one day, I'm sure there are shots there somewhere).

Only other times I saw her were on the ground in Heathrow - always a highlight of my London visits!

Mr Vortex

An ejection was recommended because it was possible, not that was necessarily impossible to land a Draken dead stick. F-16s have done a number of them, I witnessed one at KTPA. There was a video of the HUD view of one at NAS Glenview, IL.

To your question, it would depend on distance to go to the airport, glide ratio (high but probably not terribly worse than any conventional airliner) and most importantly the capability of the RAT providing hydraulic power.

M2dude, any idea of the min IAS for the RAT to provide the juice and hydraulics? Would it be as low as Vapp minus some margin?

GF

The "venom" is in the tail of your question.....
Best glide angle for Concorde is in the order of 1:10, so with an multiple failure at 40,000ft (7.5 miles) your "nearest airport" would have to be well within a distance of 75 miles.
(BTW, I think somebody earlier already mentioned that a large part of the actual descent from top-of-descent was with the engines barely above idle, so that it was much like a glide. It was during the final hold, approach and landing, that it was preferable to have a few engines left.....)

Four-engine surges have happened a few times during flight testing, but I don't think there ever has been a four-engine flameout.

Re the SAAB Draken, I would think a dead-stick landing would be possible, but only IF you could arrive 'overhead' at about 10,000ft and IF you were well aware of the horrendous sink rate 'on the back of the drag curve' once you committed to the final approach and landing.
Even the F-104G, not known for its gliding qualities, could be and has been landed dead-stick - there is a section on the subject in the flight manual. On the 104, things were further complicated by the fact that without an engine you also lost the "blown flaps", so your landing speed was a lot higher.

In Western Europe, with its densely populated areas on the one hand, and a lot of airbases on the other hand, there were certainly cases where you thought twice before 'punching out'.

CJ

QUOTE]I'm wonder if all 4 Olympus 593 all died in flight and unable to restart. Is it
possible to be able to land at the nearest airport[/QUOTE]

As CristiaanJ says , it depends on how far the nearest airfield was away, but given that there was one close enough then yes in theory it was possible.

On Concorde there were two checklist to cater for a four engine failure that assumes the engine have flamed out but not seized thus the system can be fed by windmilling engines. The two drills are

4 ENGINE FAILURE ABOVE MACH 1.2

4 ENGINE FAILURE BELOW MACH 1.2

When above M1.2 the windmilling speed of the engines should keep the engine generators on line and you should have good hyd pressure also.
Therefore the main point of the drill at this speed is to try and relight the engines, by selecting relight on all 4 engines at the same time. You normally got the chance to go through 2 and some times 3 relight sequences before the speed dropped to Mach 1.2

At mach 1.2 with no engines then the windmilling speed is reaching a point where it is not sufficent to hold the generators on line so the drill concentrates on switching as much of the systems onto essential electrics which will be supplied by the hydraulically driven emergency generator.
To help support the yellow and green hyd system below M1.2 the ram air turbine is lowered. Engine relights will continue to be attempted but as you are on essential electrics now they can only be attempted individually.

If no relights and below 10,000ft then the c/list tells you to prepare the aircraft for landing by lowering nose/visor and gear by emergency systems with speed reduced now to 270 kts. To conserve hyd pressure being mainly derived now from the RAT for the flying controls the emerg gen is switched off during the approach and approch speed is 250 kts with min landing speed
of 200kts

During this all this descent the aircraft had to be flown and navigated, radio calls made along with PA and cabin briefing and all the normall descent checklist complied with so you can imagine it was quite a busy time

This drill used to be practised on the sim ,but the crew would normally find the engines started to relight before 10,000ft so as to give the crew confidence that the drill worked.

However after many years of operation there was some talk about doing away eith the drill as no one could envisage it ever happening. then the BA 747 lost all 4 engines in the volcanic ash cloud and all such talk stopped

Thanks for the very complete answer, Brit312. As I gather, Mr Vortex is a relative novice (from the profile, I'm making an assumption), an additional point. As supersonic flight was overwater, the loss of all engines above M1.2 pretty much precluded a airport landing except for initial acceleration and final deceleration. And, at that, initial acceleration would require a 180 degree turnaround, probably reducing the time above M1.2. Over sovereign land, you would, I presume, be going directly to the slower than M1.2 drill and the possibility of an airport landing.

GF

GF, that's another thing about Concorde....
I'm always amazed about how many people, who've never flown on Concorde, sometimes never even have seen her fly, still try to find as much about her as they can, even on technical issues they'd never bother with about for any aircraft (apart from maybe the SR-71).
It's worth passing on the heritage, I think.

CJ

Thanks for all of your reply.:)

As galaxy flyer said, I'm haven't met real Concorde in my life and neither see her
flying too. :sad: So I'm study about her for a while from flight simulator, manual,
some book, and this forum to get to know more about this amazing plane.
So if i'm bother you guys with a non sense question I'm apologize for that.

Best Regards

Vortex

I'll answer that with an ancient remark...
"There are no such things as stupid questions. There are only stupid answers".
So no need to apologize.
We'll do our best to answer, and do our best to keep the Concorde story 'alive'.

CJ

More than that, ChristaanJ, there are only stupid mistakes!

Mr Vortex. At your age, I was doing the same thing, asking all sorts of questions that required knowledge and understanding before my years and experience. Keep doing so, it is the only way to expand your mind. And you never know when that obscure fact will come in handy

GF

galaxy flyer
Well the RAT was 'advertised' to be able to maintain 4000 (ish) PSI on Green and Yellow systems down to around 200 KTS, so IN THEORY you'd be ok (ish), refering to Brit312's post. Incidently, one of the prime reasons that the engines were housed in twin nacelle pairs, rather than the original TU144 'monobloc' style was to eliminate the chance of a severe ripple surges flaming out all four engines. (But as the thing had half of the engine air passing over the massive stowed main undercarriage, they had other problems to worry about anyway).
I have to echo your point GF about carrying on asking questions, even if they may seem dumb at the time. It's all about how we all had to learn in the first place; Personally I'm happy to answer any questions at all here (the questions may not be stupid, but some of my answers...........:ugh:).
Regards to all

Dude :O

Thanks to all of your cheer up reply. I'm really appreciate that. :O

Best Regards

Vortex