hi im not too familiar with pprune yet and im not sure if this is the right forum but does anyone know why the SR71 didnt use a straight wing instead of an ogee wing like the concorde? if it could cruise above mach 3 then one would think the wing itself would be a more supersonic design rather than transonic. Straight wings reduce shock wave drag where as swept wings delay supersonic airflow which is useless in hypersonic cruise...

I'm confused. The SR-71 had a delta wing.

Vinni3,
A "delta wing" is triangular.
Look at the F-102, or the French Mirages, or the Avro Vulcan, or the Valkyrie.
Those are delta wings.
The wing of the SR-71 is much closer to the "ogee" wing of Concorde.

Edit: sorry, you're not really wrong... the wing as such is pretty well triangular.
The major difference lies in the 'chines', the flat horizontal extensions of the forward fuselage, and outboard of the engine nacelles.
Their effect is the same as that of a "double delta", and similar to that of the "ogee" wing shape of Concorde.

coobg002,
I'll try to give you a reasoned answer... but later. Dinner's been called!

CJ

coobg002,

I'm not an aircraft designer, just an avionics engineer with an aeronautical engineering background, so my answer can only be partial...

Pity you cannot ask the question directly to "Clarence" Johnson, because he used both solutions for two of his best-known Mach 2+ designs...

The F-104 had indeed a very small, very thin, straight wing.
The SR-71 had a wing shape not totally unlike Concorde; admittedly the wing shape itself was more a delta, but the 'chines' of the forward part of the fuselage played an important role.


I would say.... every design is a compromise.
You don't start with a good-looking shape, you start with a specification.

In the case of the F-104 it was for an interceptor, something simple and fast, with a (relatively) limited range.
So you chose a big engine, you stuck a cockpit at the front, and you added the smallest straight wings that would do the job.
Not exactly ideal at low speed... the F-104 had huge "blown" flaps and even so it was still pretty "hot" during approach and landing.
As to what to do after an engine failure.... the procedure for a dead-stick landing was in the manual, but generally the "she flies like an angel, but she glides like a brick" would prevail, and you'd punch out.

In the case of the SR-71, much like Concorde, it was the 'spec' that was totally different.
Long-range supersonic cruise (hence space for fuel in the wing was prized), but also acceptable low-speed handling.
Think of the repeated air-to-air refuelling for the Blackbird, or the subsonic sectors in a typical LHR-JFK flight for Concorde.

So for anything that can still take off and land at an acceptable speed and perform well subsonically when needed, yet cruise at Mach 2 or Mach 3, the ogee/delta wing has turned out to be the best compromise.

CJ

Wasn't it the case that the F-104 had a reputation for killing a lot of capable pilots due to it's slow speed characteristics even WITH a working engine?

An optimist was a Luftwaffe Starfighter pilot who quit smoking!

GF

Nope.
I don't think this is the thread to discuss the F-104 story (I'll happily exchange some PMs, if you want. I was involved with the F-104 a long time ago, even if only on the sideline).
But in very brief, the German AF took on operating a big fleet of a new and not yet fully mature variant of the F-104, while lacking the needed maintenance competence, or enough pilots with the necessary skills.
The slow-speed characteristics had very little to do with it.

CJ

The SR-71 tech notes describe it as having a delta wing (Ogee applies to an S shaped wing) where the outboard portion has negative conical camber to move the centre of lift inboard to relieve loading on the nacelle carry through structure. Also improves the max lift characteristics of the outboard wing at high angles of attack and enhances crosswind landing capability.

The chines improve directional stability at increasing angles of attack at all speeds, but their primary purpose is to provide a substantial proportion of the total lift at high supersonic speeds and eliminate the need for canards or special nose up (drag producing) trimming devices.

christiaanj
 

hey mate i think youre right (by the way to the bloke who said its delta, it doesnt matter whether its delta or ogee when you are hypersonic, they both are poor when all the airflow over the upper surface is supersonic).
Anyway it must have something to do with structure design, fuel storage and transonic operations including air to air refuelling. It also might have somethng to do with getting supersonic in the first place. Even with the concorde it is sometimes a little confusing why they would use the ogee wing but i honestly think it is because cruise is not the only stage of flight, there is climb, descent and landing etc. Also, the concorde was only just supersonic (as in ALL airflow supersonic) so at times keeping the wing surface subsonic in cruise would be advantageous. I would have bloody loved to speak to the designer of the SR 71 in person, would be an interesting experience. What an aircraft

With all due respect, I don't think you have any understanding.

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?

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.

If your talking about real profit, does anyone know what the true development costs were and how many airframes they would have had to sell to break even.
With the governments (or you and I really) paying all the up front costs the suggestion that concorde was ever profitable is a bit of a myth . Technical tour de force that it was.:confused:
rod

I would say that the SR-71, and the Tu-144, are in a way honorary members of the Concorde family, so I don't mind if they fly into the discussion every now and then.

The full list of names (up to 2002) for both BA and AF can be found in "The Concorde Story" by Chris Orlebar. For BA, a quick count shows about 170 names. That book also mentions, that the maximum number of crews qualified at any one time was 28, in 1980, and that the average was about 20 crews.

Photos can lie.... or rather, they are rarely close-up enough to show clearly where corrosion has set in.

As an example, F-BVFC at Toulouse, which was the last one to remain at least taxyable, now has some patches of corrosion starting to show, when you know where to look. Not to mention the nasty smell of damp and mould in the cockpit which bodes no good for what's going on underneath the floor.

And even F-BTSD, kept "live" to some extent at Le Bourget, leaks some hydraulic fluid (like all Concordes did on the ground), so it's easy to imagine the dried-out hydraulic and fuel seals on the other museum aircraft.


http://img.photobucket.com/albums/v3...9210129w-1.jpg

And yes, that's kitty litter...
The composite material of the floor and the hydraulic fluid don't agree too well.

I'll leave M2dude to answer that one.

CJ

Have a quick look here:
Concorde FAQ
(Scroll down to "How much does a Concorde cost?" and "Did Concorde make a profit for the airlines?".)
IIRC, break-even was slightly over 100 airframes.

You are making the usual mistake of confusing development costs and operating costs.

The development costs were covered by the governments, so it that respect, yes, Concorde was a commercial disaster. Even so, the Concorde project paid for much of the groundwork of what was later to become the European Airbus consortium, so it certainly wasn't all wasted money.

BA and AF bought their first aircraft, much like all those other airlines that chickened out would have done.
Maybe they got a bit of a discount as launch customers, but they certainly paid for them!
BA and AF were never expected to pay for the development costs... you could say that was not their problem!

BA's operations were in the beginning subsidised, until they "bought out" the government, and revised their cost and pricing structure.
After that, overall, the BA Concorde operation was profitable until the end. Maybe the bottom line of the operation wasn't huge, but it was certainly positive and no myth.

AF's operations, for various reasons, were less of a success story....

CJ

With all due respect Cristiaan Im not mistaking operating costs and development costs.
If I as a company develop and sell a product then its not profitable until all the development costs have been recovered. Operating costs are a matter for the buyer, not the manufacturer.:)
I know the costs were covered by the governments and that was what I was really asking, what was the break even quantity for the manufacturers.
Obviously the benefits to the existance and technological advance of Airbus is a seperate and unquantifyable matter
rod

Sorry.
The way your question was formulated didn't make that clear to me.

Exactly.
For the governments and the manufacturers, there was never even a mention of "profits", was there?
The only serious mention of "profits" has always been the BA operation, and they were just one of the 'buyers'.
Even if in the end they acquired two more aircraft (three if you count DG) for relatively nothing, when you start looking at the operating costs over the 27 years, those totally dwarf the initial acquisition costs.

I would really have to do a 'back-of-the-envelope' calculation to extract a break-even quantity from the limited data in the link I posted earlier.
Also, Concorde #17 would already have been a prototype "B" Concorde"... how much of that is included in the development cost figure?
With only 16 production aircraft, we were only just on the start of the "learning curve"... how exactly that would have evolved compared to other aircraft is anybody's guess.
Although, there was a trend already, since the last Concordes off the production line were already a ton lighter than the first ones.

But the original figures, at various stages, for the break-even point were in the order of 100 to 150 airframes, IIRC.

Unquantifiable in money terms, yes.
In terms of years lost, maybe not entirely.
I'll have to look up all the dates. But if Concorde had been "nipped in the bud", I would guess we would have lost ten years of experience in cooperation in development and manufacture.

In a roundabout way, look at the cancellation of the Boeing 2707 SST in 1971.
The figures at the time showed that the US had spent almost exactly the same amount on SST development as had been spent for Concorde at the same time.
For that, Boeing had a hangar-full of design drawings, a couple of nice-looking wooden mock-ups, and a few test articles for the swing-wing.
At the same date, we already had two prototypes and a pre-prod aircraft flying, and the production line getting under way.

What did we gain? Only a few Concordes, but also a European aircraft industry capable of meeting Boeing on its own terms.

What did Boeing gain? Some swing-wing design experience for the B1.. and even that wasn't much use... look at the B1-B.

CJ

Yes Its all a terrible terrible waste.
So you have to ask why nobody foresaw the problems of supersonic flight over populated areas, If it hadnt been for that maybe concorde would have been a commercial success as distinct from a technological one.
rod

Biggles78
oooo that's a hard one to answer. The financial crisis that we are (I hope) clambering out of would almost certainly have impacted in a big way the load factors on the aeroplane. This almost certainly would have resulted in at least a severe curtailment in the operating schedule, but quite possibly now she would be absolutely THRIVING in the recovering world airline business. To answer your question fully, I think that there would at least NOW have been the willing and ability within the airline to keep her going in a big way, but there would be major expense over the last and next few years. The FAA SFAR88 directive would have already resulted in a major review of all fuel tank wiring and components. (However this appplies to any aircraft, ageing ones in particular). EGPWS would have been mandated by now, which means provision for at least one (probably two) GPS antennas. This upside of this would have meant the relative ease of incorporating a more accurate navigation system, the Litton LN93 system (Laser INS with GPS update) was already being looked at before retirement. A major structural modification to the fuselage crown area would certainly have been mandated under the FAA/EASA ageing aircraft programme, although the mods were pretty much drawn up before retirement (and would have been a permanent fix for the one chink in her supersonic armour). It is also probable that predictive windshear would have been activated. (The Bendix RDR4a had this capability but it was disabled in Concorde). I think that for PWS and RWS to operate correctly you'd need some sort of pilot display in any case.
Another seperate issue would be having sufficient 'O' licensed Engineering Officers in the airline; due to basic demographics there would be precious few left in the airline now. (My personal guess is that pilots would have to be trained as to qualify as P3's).
So although it would be far from easy to keep her going, if she was earning sufficient current and potential revenues, then I'd say yep!! (But this is just my humble opinion of course).

Dude :O

Whilst Concorde only resulted in a small production run and from that perspective it was not successful. I think that CJ's last post shows that the (unforseen at the time) spin offs and the subsequent success of Airbus means that in my view Concorde was not "a terrible terrible waste".

Maybe this is not the right place to ask this but I have been wondering for a while what leasons have been learnt from Concorde that could be applied to the design of a future SST? I hope it's not that one should never again be attempted!
Regards
Nick

M2dude,
It's the answer I would have given, but without your know-how and background.
Also, the near-monopoly, with only a hundred seats on offer a day, would probably have assured enough customers for whom time was indeed money, and for whom being able to 'pop over' to NY and back the same day, in person, wold far outweigh 'video conferencing'.

If I said 'near-monopoly', it was because 'straight-out' / 'straight-back-in' business jets are already aiming to provide a similar (if not the same) service, with the added advantage, compared to LHR-JFK-LHR, of being capable of providing more "door-to-door".

I suspect that, if a SSBJ didn't need so much "back from the ground up" engineering, one would already be flying.

CJ

Nick Thomas
Hi again Nick, I totally agree that anyone suggesting tha Concorde was a 'terrible waste' is either totally mis-informed or naive; either way they are totally wrong anyway. The Airbus spinoffs as well as the know how gained on both sides of the English Puddle were immense. What she brought to BA as a brand of course is a totally different matter; for BA she was just the best thing since sliced bread.
As far as another SST, well you never know. I maintain that in aviation you can never say 'never', but far more likely than an SST as such is a hypersonic sub-orbital machine such as the Reaction Engines Lapcat. In any case such a venture will require immense financial investment as well as HUGE political balls to have any sort of chance of becoming anything more than a paper aeroplane. More conventional SST designs are around both in Europe and Japan, perhaps a trans-continental venture is the answer here?

ChristiaanJ
I'm with you on the business jet angle, it's such a quick and convenient way of getting from city centre to city centre. And as for the SSBJ, it did sound promising didn't it, that would have been the ultimate business travel tool. (Shall you and I design a 'mini-conc') ?:D
Regards to all

Dude :O

SSBJ?
 

M2Dude wrote:

You'd have to say that designing and building the aeroplane probably isn't the tough issue. I mean you could probably adapt a military design - a Tornado can lift more than six tons of stores can it not? So that's a ton of people, a ton of bling to keep them comfortable and four tons of fuel ...... oh.:uhoh:

The tough thing needed, the really clever thing that Concorde did and no other aeroplane, sorry, only one other aeroplane - our 'honorary Concorde' the SR71 - would be to design the engine /intake /nozzle configuration that would let our 'Tonkorde' supercruise at Mach two, while running on the smell of the stuff. :ok:

Roger.

As a Yank, the Concorde was Europe's, including the UK, of course, Apollo project. And nothing short of it, either. Concorde required industrial cooperation and collaboration on a huge scale, ground-breaking technology that is still paying back in the 21st century and required political daring unheard of today. Huge applause! :ok::D:D

Think of the Sixties projects--Apollo, Concorde, 747, SR-71, motorways, the Beatles, miniskirts--none possible today, the politics alone would kill 'em.

GF

GF I agree totally. All great projects and Apollo, Concorde and the SR 71( a plane I know very little about but from what I have read on this thread, it's obvious that I should make ever effort to find out more. An interesting way to spend these cold winter evenings) were all conceived within approx 50 years of the Wright brothers first powered flight. (Typing conceived reminded me of the other great sixities advance designed to stop that. Extreme thread drift so I apologise in advance!).
Once again thanks to M2dude and CJ for being so generous with your time and knowledge.
Nick

Can I just throw a comment in ?

In about 1992/1993 [not sure of the date now] I was lucky enough to exchange my JED->LHR BA Economy ticket for a Concorde Ticket for 400 notes.

All I can really remember about the flight is the noise, acceleration and comfort [not to mention the stunningly good on-board service Landlady]. I got a quick cockpit visit and have a treasured photo of me crouching between the pilots.

I know it's a long shot but did anyone here crew on one of the flights to Jeddah ?

Oh, I forgot the "two shoves in the back" presumably from inboard/outboard application of reheat to go through the sound barrier.

Thanks for a wonderfully informative thread - it's so heartening to see so many people who haven't forgotten this aircraft.

Sorry again folks more misunderstanding when I said terrible waste I meant the cancellation and grounding not the work done
rod

Landroger
SSBJ is Supersonic Business Jet Rog', there have been a few designs but the most famous (and had the most potential) was the Sukhoi-Gulfsteam S21. This aircraft would carry about a dozen passenges at Mach 2.2, with a range of 4,500 miles. Gulfstram pulled out of the partnership; there werer serious doubts about the viability of the Russian engine as well as serious aerodynamic issues too.
I would not personally utter 'Concorde and Tornado' in the same breath Rog; you need to carry this 6 tonnes over more than several HUNDRED miles. There is absolutely no comparison between the performance of Concorde and the Tornado I'm afraid, you'd need to base any military adaption on a far better design than that.
Although design of the powerplant for any future SST is pivotal to the whole design, you still need an aerodynamic model with a significantly higher lift/drag ratio than Concorde to make the project viable. And as good as the SR-71 was (I'm one of her biggest fans) she was still using afterburning/reheat at Mach 3 cruise.
galaxy flyer
Great to see you back here GF. I DO hope that you are wrong about mini-skirts :{
You are so right about the massive industrial collaboration required; it seems that there was so much more of a 'daring spirit' in the 1960's, makes you wonder where all the balls have gone today. (Oh I know, there are so much more deserving :\ causes than aviation for us to spend BILLIONS of $'s and £'s on today).
Nick Thomas
No need to apologise for any thread drift Nick; this is such a diverse thread now; your points are perfectly valid here. And thanks for your kind comments again Nick; CJ the rest of the guys and myself are more than happy to bore the socks off of you and all the other posters and readers.
hoofie
So glad that you enjoyed your Concorde experience. The Jeddah flights were a fairly brief 'experiment',it would be great if one of my pilot/flight engineer friends here did a trip, we'll soon know. The double 'shove in the back' would indeed as you say have been the inboard/outboard reheat selection. Glad you are enjoying the thread, it is certainly bringing back memories for me about this seemingly eternal aereplane.
jodeliste
No problem Rod, I think most of us here agree about that one. A terrible waste and a giant leap BACKWARD in aviation.

Dude :O

Still be interested to know if anyone foresaw the supersonic over habitation problem and if so why it was not seen as important at the outset?
rod

That's not the first thing that sprang to mind* :}







(*must get it out of the gutter)

Forgotten point ...
 

While working at a certain establishment near the banks of the Garonne, it occurred to me one day that, while the US and USSR were busy fielding Mach 2 bombers, two European nations working together developed and for many years successfully operated an equally fast aircraft for peaceful purposes.
After living and working in Germany beforehand during a period where the possibility of being nuked (or just irradiated by fall-out) if the Cold War got hot (and it seemed about to do so from time to time) was very much on many people's minds, Concorde's peaceful purpose was a real and welcome contrast.
A beautiful creation, whether airborne or standing as a gate guardian, not built to destroy or deter.
The only thing it threatened, perhaps, was a perception in the US that it threatened their supremacy in the commercial world - which they also felt about the concurrent Airbus project in the subsonic market. And we all know where that led !

I rather think that the US did know a lot about supersonic flight over land by large and heavy aircraft.. part of the NASA operations with the XB-70 were precisely aimed at establishing that...and they had a few years of experience with the B-58.

That being said a quandary would have existed....the effects were known..and yet there was massive government investment and pressure to develop exactly the type of airframe that generates these effects.

At some point during the development of Concorde, there were a number of flights performed in the UK where RAF Lightnings flew at supersonic speed over various places to assess the effects, including how many complaints were received.

I don't remember exactly when this happened, but I would guess about 1970. What I do remember was being in my bedroom in North London when there was a double boom and just managing to see for an instant the aircraft that made it heading south towards Central London before disappearing behind the trees and houses at the bottom of our garden. I can't recall how high it was flying but it did look very small from my perspective.

Of course by this time Concorde was already flying so it was clear that it would have to stick with its general configuration and deal with overflight problems by changes in routing, but I did enjoy the experience. I think it was the first sonic boom I had ever heard, but I was already interested enough in aircraft to know what it was.

Feathers McGraw,
Nice one.
Concorde itself also did some of the early test flying in "boom alley", a route along the west coast of Scotland and over the Irish Sea.
The result was the usual batch of bogus claims for glass damage, minks eating their young, etc., even on days when Concorde didn't fly....

I would say that 99% of the stories about Concorde (and other supersonic aircraft) actually causing damage are fiction.
However, a sonic bang IS loud, and totally unexpected, hence startling, and NOT what you want when you are doing a precision job, for instance.
IMO a few dozen bangs a day, every day, would never have been acceptable.

(Where I live, we get about one a month, when a Mirage returning from the Mediterranean misjudges his deceleration, so I'm still regularly reminded of what they sound like.)

Christian

Tonkorde.
 

Sorry Dude, didn't realise that use of the 'T' word would upset you so! :) Perhaps you were frightened by one when you were a baby? :D:D I picked the T*****o randomly to illustrate the contrast between a military supersonic design and Concorde. She really wasn't a converted bomber and even by using up every ounce of a Tonka's lifting capacity, it would still run out of fuel before it reached the Fastnet Rocks, let alone anywhere useful. :eek:

I must have missed something about the SR71 while we were discussing 'Inlet Thrust' on the other thread. I thought there was at least some part of the performance envelope where the Blackbird 'supercruised?' If not, then Concorde's ability in this area is all the more astonishing. :ok:

While mentioning the SR71, a striking image of them - to me anyway - was of the streams of fuel, leaking from every seam of the fuselage immediately following in-flight refuelling. These apparently 'sealed up' when she expanded in supersonic flight. How did Concorde avoid this rather startling phenomenon?

Roger.

Landroger
Come on Rog, let's not be silly now. I was not 'upset', and you can use the 'T' word any time you feel that you need to lad. It's just that you used a very poor example to use when, I don't know what your point was anyway, comparing Concorde with any other aeroplane.
The J58 powerplant design for the SR-71 is superb, and considering the early 1960's era that it was developed, was nothing short of astounding.
For Mach 3 cruise air is bypassed around the engine core and fed staright into the afterburner duct, where it supplied the afterburner directly. Still a remarkable design though, even now.
Oh she didn't; she just leaked. (not on the same scale as the SR-71 though).. If you were nuts enough to walk under a fully fueled Concorde without an umbrella you often got quite wet and smelly. The leaks were 'drips' and not running streams, and maximum permissable leak rates were mandated and controlled, but if she became particularly 'drippy' it was straight back to the hangar for tank re-sealing for our Concorde. The fuel tanks were sealed using liquid viton rubber, the idea being that the viton when it solidified would filll in all the nooks and crannies of the tanks. Controlling leaks was one of the most time and labour consuming aspects of Concorde maintenance, to get in and seal some of the smaller tanks was challenging to say the least, and some pretty small chappies were required for some of the tank areas.
I still remember that when we were building Concorde, this idiot of a production manager at Filton (the same one that was responsible for the debacle of G-BOAD sitting on her tail) insisted that the fuel tanks were filled with fuel as soon as the tanks were completed, whether the sealant was dry or not. I still wonder how much of the in-service leak maladies could be directly attributed to him.

Dude :O

Fascinating stuff again Dude, I'd never realised that even that leak rate existed on Concorde but then maybe other airliners leak a bit too, I don't make a habit of walking around under them (more's the pity).

As for the SR-71, the construction was a bit like a lot of ribs with sliding clips that attached the skins to them, hence things could slide about to cope with the heating at Mach 3+. Kelly Johnson often referred to this as his "Mach 3 Ford Tri-motor".

The fuel used (JP-7) had a tendency to rot the wiring in the aircraft, so they were re-wired quite often during their lives. All Sleds sat in pools of fuel when hangared, unless they were totally empty.

Refuelling was usually carried out at about 33,000 feet, and as the tanks filled it became necessary to light minimum afterburner on one engine to maintain contact with the tanker. The nose was always yawed the same way because only one of the windshield panes was de-misted so this side was always used to maintain sight of the tanker's underside.

After tanking a descent was commenced to about 26,000 feet to help with acceleration to supersonic speed, as far as I am aware all supersonic flight was made with afterburner selected.

I remember reading some time ago that fuel consumption was in order of 8,000 US gal per hour. Not sure if that is an average or whether it covers only Mach 3 cruise.

Hello all to all members and Concorde Expert,

I have been read this thread and it is so great. I'm enjoy reading it all day long!!
I have some question that I'm wonder about the Concorde.

1. I've heard that Concorde use the primary nozzle to modulate the noise and
the speed of the N1 compressor. How does it work? and does it help to reduce
the noise a lot?

2.Another thing about Primary nozzle. If i recall it correctly, the primary nozzle
can also use to control the Inlet Turbine temperature. Is that true? How is that work?

3.Finally, does some one have a schematic or the fuel vent system? :8

That's all of it. I will transform in to a nerd man reading a Concorde book in
the next couple days. :O

Thanks for all of yours reply.:ok:

Mr Vortex
First of all, 'welcome aboard'; I'll do my best to answer your queries.
The area of the primary nozzle Aj, was varied for 2 'primary' purposes :p:
a) To act as a military type 'reheat' or 'afterburning' nozzle; opening up to control the rise in jet pipe pressure P7, as reheat is in operated.
b) To match the INLET TOTAL TEMPERATURE RELATED (T1) speed of the LP compressor N1 to the HP compressor N2 against a series of schedules, ensuring easch spool is as close as safely possible to its respective surge boundary, (with a constant TET, see below) and therefore at peak efficiency.
Now, in doing this a complex set of variables were in place. As the nozzle is opened there is a REDUCED pressure and temperature drop across the LP turbine. This has the effect of enabling a HIGHER N1,as less work is being done by the turbine. Also the change (in this case a decrease) in the temperature drop across the turbine will obviously affect the turbine entry temperature, TET. A closing down of the nozzle would obviously have the opposite effect, with a DECREASE in N1 and an INCREASE in TET.
In practice at a given T1 there was always an ideal N1 versus N2 on the control schedule (known as the E Schedule), the TET staying more or less constant from TAKE-OFF to SUPERSONIC CRUISE!!
As far as noise abatement went; when reheat was cancelled and power reduced after take-off, an E Schedule known as E Flyover was automatically invoked. This had the effect of driving the primary nozzle nearly wide open, reducing both the velocity of the jet efflux and in essence the noise below the aircraft.
The real beauty of this primary nozzle system was that it really did not care if the engine was operating dry or with afterburning ('it' did not even know). P7 was controlled against a varying compressor outlet pressure, the variable being controlled by a needle valve operated by the electronic engine controller. (If this is unclear I can post a diagram here that shows this control in action).

As soon as I receive back the majority of my technical notes that I have out on long-term loan (I've requested their return) I will post a schematic here. But for now; The tanks were vented to atmosphere via tandem vent galleries, the two vents openings being on the left hand side of the tail-cone. At an absolute static pressure of 2.2 PSIA (around 44,000') twin electrically operated vent valves, also in the tail-cone, would automatically close; the tanks now being pressurised via a small NACA duct on the right side of the fin. A tank pressure of around 1.5 PSIG was maintained by the action of a small pneumatic valve at the rear of the aircraft. There was massive protection built in to guard against over-pressure (eg. if a tank over-filled in cruise).

I hope this answers some of your queries
Best Regards

Dude :O

It is still difficult to grasp the fact that, with the one exception Christiaan has told us about, all of the control electronics in Concorde were analogue. Some of the little tweaks Dude has just alluded to in his reply about the nozzles and the relationship of compressor speeds, for example. Most of them would be relatively easy - relative is a huge word of course :rolleyes: - if they were microprocessor controlled locally and sending/ receiving status and demand data to a bank of central computers. But to do it with analogue signals and controllers is mind boggling. :eek:

How all these signals and rates were calibrated and stayed calibrated is a mystery. The earliest scanners I worked on - mid seventies - were largely digital even then, but they did have quite big chunks of analogue circuitry. Virtually every process had to be self calibrating, most of them at the start of every scan. Even then drift was often a problem and sometimes problems would arise where drift exceeded the authority of the self calibration to manage it. :{

These pages of Concorde information are incredibly interesting, with more and more eyebrow raising revelations with each page. I still think that the nicest observation made was by Galaxy Flyer - an American, when many of his compatriots tend to the 'not invented here' school of appreciation.

And to compare Concorde with say the Apollo Project which inspired many a UK engineer, is praise indeed.:D

Roger.