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.
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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