ITman, nice question.
I haven't seen any of the detailed (block) diagrams, so I'm not sure at all how the sidestick was "hooked into" the AFCS.

Don't forget Concorde already used "electrical flying control signalling" (aka "Fly-By-Wire")., so system integration would have been easier than on some other aircraft.

For those unfamiliar with the story... F-WTSB, very late in its career, was used for some flight trials with a sidestick controller fitted to the left-hand position (the right-hand seat controls still being the normal ones,and with the right-hand seat occupied by a 'safety' pilot).
The flight test data were later "fed" into the A-320 programme.

How much of the "rate" control and other A-320 control logic was already implemented in the test system is unknown, AFAIK....
Would be interesting to know some more about it, I agree!

CJ

The side stick fitted to 201 (in 1977 according to Flight International), was very much proof of concept for what would be the future A320 programme sponsored by the French government, very very limited hours were flown using it apparently (like 10!). The next step I believe in the development was to fit it onto a FBW modified A300 in the early 80s, but for the initial tests to see if a pilot could fly with a "computer joystick" it had to be done on Concorde as this was the only a/c with a suitable FBW system.

It would be good to know how it was done, but I guess it could have been wired into the emergency flight control system, which relied on electrical strain gauge inputs to move the control surfaces if there was a control column jam.

asc12


Well yes, there is no magic difference. You could calculate the lift and drag using the same methods as you would for any other delta winged aircraft, or indeed for aircraft with a 'classic' planform. You might have a bit of trouble handling the effects of camber, especially leading edge camber, if you were starting from a clean sheet of paper, but skin friction, form drag and lift curve slope (attached flow) are all calculable by standard methods. You might be pushed to get a decent estimate of lift dependent drag - I spent many hours in my youth looking for wind tunnel results on low aspect ratio delta wings to get some idea of what might be expected, but once you have tunnel tests on 'your' aircraft course there is no problem.


Again the answer is yes - in subsonic cruise (0.93M in this case) exactly the same sort of aerodynamics applies - different in detail, but the same in principle.


CliveL

SSD

I should perhaps add a bit to my first response, which was:

Although delta wings do not stall in the classic sense there is nevertheless a limit to what lift they can provide. As the AoA increases the vortices also increase in intensity, but there comes a point where the vortex flow becomes unstable and the vortex 'bursts', i.e. the circular motion degenerates into chaos and the diameter of the 'vortex' increases greatly.


The point in the vortex track at which this happens moves up towards the wing TE as AoA increases and when it reaches the TE the wing pressure distributions change and you get a break in the pitching moment curve. This happens earlier on one wing if you have sideslip, so you then tend to get a wing drop. This does not meet the airworthiness requirements so effectively vortex bursting over the wing equates to stalling.


[On another thread it has been pointed out that on the FA18 vortex bursting (off the LE extension) has caused handling problems due to interference with the fins]

I can't add too much as I was only on the fringes of this.


I think it might have been done by fitting a D/A converter to substitute the digital signals from the sidestick for the normal Concorde stick resolver output. The 'laws' could then be treated as a special case of pitch damper etc. inputs so that the standard Concorde electrical signalling system could be used downstream. I don't know this for sure, it is just a thought - maybe Christiaan could comment on its feasibility.


I think they were looking at at least the rate control but probably not all the envelope protections. Certainly at that time we were having discussions with them about the merits of their FBW laws against the laws we (BAe) were trying out on our BAC1-11 flying test bed. No prizes for guessing who won that argument. :ouch:


And before anyone asks; no I don't remember (if I ever knew) how we were implementing FBW into the 1-11!


CliveL

My only reasoning for guessing on the Emg flight system was that its would be easy to turn on and off and recover to the normal flying controls.

For a very short test programme, well ahead of any A320 programme which did not come about till 1984, I suspect this was no more than a belt and braces to see if you could fly an aircraft from a side mounted stick.

GordonRoxburgh
 

That cannot of been the sole objective, surely Gordon? Concorde was far too complex and expensive an aeroplane to simply want to prove that with her? Wasn't the F16 flying then? That had side stick - and a 'lay down in the bath' seating position didn't it? :eek:

As for the aerodynamics, what a fascinating discussion! I'll readily admit it is mostly on the fringes and way above my understanding, but I can hang on to enough of it to make the subject utterly intriguing. My maths are not and never were anywhere near good enough to make this a career choice, but the image conjured of vorteces and laminar flows and shock waves is quite beautiful.

Thanks again everyone.

Roger.

Gordon,

[quote] My only reasoning for guessing on the Emg flight system was that its would be easy to turn on and off and recover to the normal flying controls. [quote]

I see what you mean, but surely it would be just as easy to insert a kill switch in other systems?

I'm with Landroger on this in that I feel they would want to do a lot more than just find out if aircraft can be flown with a sidestick. I would expect them to want to know about how much stick movement was optimum and this they could not do with the EMG solution (if I have read your remarks correctly that would have been a stick fixed/force signalled system?)

I am also pretty certain that they investigated control laws; with a simple 'can you fly with a sidestick?' system they would surely be effectively in a electronic version of mechanical signalling?, and although you could fly the bird in mechanical it would be making life difficult for yourself, which is the last thing you want to do when investigating something really new.

I think Gordon probably meant "airliner" rather than "aircraft".

The implementation of FBW on the F-16 was intended to solve a very different problem than that of the A320 series. The F-16 was one of the most maneouverable fighters of it's day, but the way General Dynamics achieved that was by having an aerodynamically unstable airframe that *required* constant computer correction to keep her airborne and going in a straight line. The A320 was designed to be as aerodynamically stable as any other airliner, but the FBW was simply designed to assist the pilot by easing the workload when it came to actually controlling the thing, as well as provide safety features as backstops when things got hairy.

The only Western analogue FBW aircraft of the time of comparable size to an airliner (IIRC) were the Avro Vulcan and Concorde. France had no Vulcans, so the airworthy test Concorde they had to hand was the obvious choice.

I personally doubt very much if the Emergency Pilot would be the 'way in' for the sidestick input. EFC ROLL commands were inputed from the SFC computer to the Autostab computers as 'stab demands' and therefore drove the MIDDLE and OUTER elevons only for roll. To make matters worse, if your test flight was really 'exciting' and you found yourself at any time at Vmo + 20 KTS, roll control would be through the middle elevons ONLY. I'm with CliveL in that the most likely scenario would be for the demand would feed via a D/A converter somehow. (It would be great to find out though).
I would have thought that the whole venture was a proof of concept by SFENA for future implementation in the Airbus family. This excersise would have been both costly and highly complex at system level, any other reason would really have been quite daft.

Best Regards
Dude :O

If the Flight article from the 80s that says only 10 hrs of flying was done is correct, it can only have been for limited in flight handling and not anything approaching the limits of the understood flight envelope......and I sure you would not have been contemplating take offs and landings.

A few of the Toulouse ex pats might be the people who would know, Dudley Collard etc...

Farewell Tour Details
 

Hi,

I am trying to find out some details of the Farewell Tour for a project I am undertaking.

The flights I refer to were are the following:

Heathrow - Birmingham - Heathrow (20 October 2003)
Heathrow - Belfast - Heathrow (21 October 2003)
Heathrow - Manchester - Heathrow (22 October 2003)
Heathrow - Cardiff - Heathrow (23 October 2003)
Heathrow - Edinburgh - Heathrow (24 October 2003)

All of these flights were scheduled to leave Heathrow at 10:00 hours and arrive at their respective locations at 11:45, and the return was to leave at 16:05 and arrive at Heathrow at 17:45 (apart from the last Edinburgh flight which left Edinburgh earlier in order to get to Heathrow around 16:00)

Does anybody have any details of the routings that these flights took? I have some information about the Edinburgh flight but I cannot find anything out about the others, if anyone can supply me with anything it would be very much appreciated.

Also, were these flights purely subsonic or was there a short supersonic section in there somewhere, after all it doesn't take 1:45 to get to Cardiff, Birmingham or Manchester etc if you go direct.

Many thanks in advance for anything you can offer.

Regards,

Steve.

Steve,

I don't have exact details, but I understand the Manchester, Birmingham, Cardiff and Belfast flights were supersonic "round the bay". The round the bay was essentially a trip out to 8w on the normal supersonic flight path, turning 70 miles around the tip of lands end, then decelerating back in down the English channel over Guernsey, where they then routed to the relevant airports.

Edinburgh was supersonic out over the north sea.

gordonroxburgh
It matters not I'm afraid Gordon. I would not have thought that anyone would design ANY flying control system, experimental or otherwise, that does not have full potential authority in all axis. := As we do not know what the PROPOSED flight regime was, on the part of SFENA and Aerospatiale,we also can not assume that any particular manoeuvr would not have been considered. (But as I said before, it would be great to find out the whole story).
The limited authority for roll autostabilisation (and hence Emergency Flight Control) was of course a very deliberate piece of design. (You could test the Emergency Pilot on the ground at ADC Test 2 (Which simulated several seperate overspeeds, including Vmo +20) and when you put in a roll demand (against some resistance), only the MIDDLE elevons deflected. It really looked wierd on the ICOVOL as well as outside the aircraft.
(To any chaps or chapesses who are not aware, above Vmo+20 KCAS, a system known as OUTER ELEVON NEUTRALISATION was invoked, where any input demand to the outer elevons was met by an automatic equal and OPPOSITE input, that of course completely neutralised the demand, giving a zero OUTER elevon deflection).

Best regards
Dude :O

gordonroxburgh,

Many thanks for that, I had a feeling that's how it would have been.

I assume the return would be routed from say Birmingham or Manchester towards UPGAS to enable it to pick up the normal routing to do the trip out to 8 West and then back into Heathrow.

Not sure how the Belfast one would have routed though, back down to the Bristol Channel via the Irish Sea, or cut across Ireland and pick the track back up when she was back over the Atlantic?

Thanks,

Steve.

FBW Aircraft of the 60s
 

"The only Western analogue FBW aircraft of the time of comparable size to an airliner (IIRC) were the Avro Vulcan and Concorde. France had no Vulcans, so the airworthy test Concorde they had to hand was the obvious choice."

The Vulcan wasn't pure fly-by-wire. It's control surfaces were remotely signalled but had a physical connection rather than electrical. Sort of fly-by-stiff wire :-)

One of the spin-offs of having Concorde at Manchester is that it is used by many different organisations for events. One a while back had a discussion about Technology benefits due to Concorde, part of that was about Concordes "1sts". First FBW was challenged as the feeling was that there must have been another by then. Nobody could think of another so it stood the debate. Is anyone aware of any others ?

FBW Aircraft of the 60s
 

If you limit consideration to aircraft that entered serial production, you may be correct. If aircraft that were prototyped and flew are included then the Avro Arrow was probably the first, as it was designed, flew a partial test program, and got cancelled all prior to 1960!

Not the first time that's mentioned.
Do you (or does anybody ele) have a schematic of the Vulcan system?
It should be on my CD of the Vulcan manual, but unfortunately my CD drive is on strike.....

MFgeo, I think we're talking Europe here... the Avro Arrow was Canadian,so I would think it unlikely the flight test results would have been available to Airbus.

CJ

Knowing more now about the safety system, I am agreement with you, getting straight in at resolver level looks the best bet on how it may have been done.

I have some feelers out to see if I can get Dudley C's contact details. As Gordon says, he would/should be a good source - keep fingers crossed

CliveL

Vulcan Schematic
 

ChristianJ

Is this what you wanted ?

http://www.flickr.com/photos/josh43/5659650094/

Thanks, johnjosh43.

Not a hundred percent legible (lack of resolution), but I'll try to decipher it.

I agree, no trace of any electrical signalling ("FBW").

CJ

Fuel Burn
 

I have been reading these all night, and find all this information really helpful in learning more about this wonderful aircraft.. I do have a question, what was the fuel burn in Mach 2 cruise?? I did not find anything specific about that, and I was just curious..

Thanks
Mark M

About 18 tons an hour I think. More like 80 tons an hour at take-off! The higher and faster she went, the more efficient she became!

Thats gotta be 18 tons (2000 lb) or roughly 9000 lbs per hour, at cruise?? The 80 ton to top of climb would be 40000 lbs an hour??? Wow..

Thanks
Mark

I don't know the fuel flow figures but from the type certificate data the max fuel load was 210,000 lbs and the max take off weight was 410,000 lbs. More than half its weight at take off was fuel.

The figure of 18 tons per hour or about 40,000 lbs per hour in the cruise would be about right as the max duration of flight was about 4 hours.

For a mid-cruise weight of say 300,000 lb and a lift/drag ratio of 7.5 the thrust required would have been 40,000 lbf and the powerplant sfc was around 1 lb/hr/lbf, so 40,000 lb/hr is just about right.

CliveL

Out of interest with any successor to concorde, what lift/drag ratio is now technically possible, and likewise from more advanced powerplants that could be available now what lb/hr/lbf numbers could be achieved?

One other question if I may - how much of a compromise was concorde's wing with respect to the balance of supersonic vs sub-sonic efficiency? What I'm trying to ask is if the wing could be a variable geometry with no weight cost (impossible I know) how much more efficient could the supersonic wing have become - or was the compromise very much on the sub-sonic performance and not much to gain in terms of supersonic efficiency?

Once more - thanks for all the great answers to the really intriguing questions!! I'm fascinated by Concorde - and regret I never had the means to fly on her whilst she was still where she belongs!

I'll try!

The last time I had anything to do with it people were talking about L/Ds around 10.5 in cruise (up from 7.5).

There are technical issues why one cannot use high bypass engines for supersonic cruise, so the thermodynamic cycle would be much the same as the Olympus. That being so the only real gain would come from higher TETs today so the benefits would be limited - two or three percent sfc perhaps?

[Yes I know the USAF are flying supersonic cruise aircraft, but look at how much bypass their engines actually have and the supersonic cruise Mach Numbers]

Obviously the MOST IMPORTANT condition was supersonic cruise, so this dominated the compromise. OTOH, the reserve fuel was largely driven by subsonic performance, so one couldn't give too much away. It might surprise people, but the 0.93M specific range is much the same as the 2.0M value.

As for variable geometry wings (1970s style), the best I can offer is that Boeing started with a variable geometry design (with which they won the design competition), but as the design process progressed the amount of wing that varied got less and less until the Boeing aircraft looked very much like the Lockheed design that lost the original competition.

What do you think?;)

CiveL

Concorde Take-Off. MTOW, LHR, Calm, ISA day, Fuel SG 0.80

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Concorde Cruise/Climb. 140,000 kgs, ISA, Still Air, Optimum altitude for her weight, speed and number of operating engines:

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Concorde fuel usage.

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Concorde Range reduction.


It was this last figure, the circa 30% loss of range following an engine shutdown and subsequent deceleration to subsonic cruise, that perhaps most occupied the minds of her operating crews.

Coupled with the change from a generally benign environment of low winds and low temperatures at FL550+, to the more hostile environment of high temperatures and much stronger (head)winds to be expected around FL290, this meant that on routes such as LHR-BGI, the greater challenge was often keeping the 3-engined diversion airfield (usually ANU) in range, rather than the destination airfield (BGI).

Fortunately the fuel planning and monitoring on this route was eased greatly with the publication of some pilot-friendly "How-Goes-It" types of graphs and charts by one particularly bright Flight Engineer.

LHR-BGI, always a challenge, always enjoyable!


Best Regards

Bellerophon

I stand corrected, but am surprised it was so high :O

CliveL

You got me a little worried there, so I've just checked the figures I quoted in case I'd slipped up! They were extracted from the Cruise Control Manual (rather than from observation on an actual flight) for a lecture some years ago.

I'm relieved to say they appear to be correct. By way of contrast, to show the variation in fuel flow there could be, the following is perhaps typical of Concorde approaching her decel/descent point into BGI.


Concorde Cruise/Climb. 110,000 kgs, FL600, ISA -15°C:

Best Regards

Bellerophon

Bellerephon

Digging a little I see that your numbers correspond to an sfc of 1.23 where I was remembering a value around 1.0.
I forgot the installation losses :O

Best Regards

Clive

So, uh, what's happening here?

Feòrag NicBhrìde - So, what's this then?

Some very odd activity around Concorde recently at LHR, or so the poster claims. No idea if the pic is genuine or how recent it is if so, but it can't be that old.

Here's the link to the same image in Google Maps


So it is kosher.

June 27th, 2010 according to Google Earth :8

Well Google is wrong!

She has been moved to the new location!!

Google was right....

G-BOAB has been moved around LHR repeatedly, and she was indeed parked for some time inside the old "detuner" (engine run-up silencer), which is what that recent "what's this then" post and picture are all about.

It's a pity, really.... All the other British Concordes have found a "home" one way or another (except G-BOAF, maybe,, but let's not go into that for the moment), and G-BOAB is slowly becoming the "forgotten" Concorde.

CJ

You could send her over here, I'm sure there plenty of people in Aus who would love to give lots of love and attention!