Concorde question

[ChristiaanJ]

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

[M2dude]

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') ?
Regards to all

Dude

[Landroger]

SSBJ?

M2Dude wrote:

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' ?
Regards to all

Dude

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.

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.

Roger.

[galaxy flyer]

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!

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

GF

[Nick Thomas]

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

[hoofie]

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.

[jodeliste]

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

[M2dude]

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

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

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

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

No problem Rod, I think most of us here agree about that one. A terrible waste and a giant leap BACKWARD in aviation.

Dude

[jodeliste]

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

[Mike-Bracknell]

Originally Posted by M2dude

Landroger
SSBJ is Supersonic Business Jet Rog'

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







(*must get it out of the gutter)

[Jig Peter]

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 !

[mfaff]

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.

[Feathers McGraw]

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.

[ChristiaanJ]

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

[Landroger]

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? 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.

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.

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.

[M2dude]

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.

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?

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

[Feathers McGraw]

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.

[Mr.Vortex]

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?

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

Thanks for all of yours reply.

[M2dude]

Mr Vortex

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

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 :
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).

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

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

[Landroger]

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 - 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.

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.

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!

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

Roger.