Concorde question
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Hi Christiaan
I have noticed that I missed a bit in my earlier reply, You will not find a CPU chip as you suggested ,instead an ALU was used with sub-routines it was a RISC before they were invented.].
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a quick question : was it possible to have 2 supersonic runs on the same flight?
Meaning 2 separate Supersonic legs with a subsonic one in the middle for say tech reasons or just sonic bang suppression over a sensitive area ..
And another while I am here , on the LHR -Bahrein route when did supersonic flight actually started and where it ended...?
Meaning 2 separate Supersonic legs with a subsonic one in the middle for say tech reasons or just sonic bang suppression over a sensitive area ..
And another while I am here , on the LHR -Bahrein route when did supersonic flight actually started and where it ended...?
Regarding your first question I don't see any regular routing where this would have happened. I think there would not be any technical impossibility, though.
For the second part I guess somewhere above the Adriatic? But would be curious to know too...
For the second part I guess somewhere above the Adriatic? But would be curious to know too...
Last edited by atakacs; 3rd Mar 2021 at 19:04.
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Probably the early marketing flight planning software had no means of calculating that.
I believe a double acceleration-deceleration on a single sector was considered to be too fuel thirsty.
There may have been other limitations such as managing the c.g.
I believe a double acceleration-deceleration on a single sector was considered to be too fuel thirsty.
There may have been other limitations such as managing the c.g.
AF registrations
Hi all,
thanks for the read. I think I've managed every single post (although I skimmed some of the *deeply* technical stuff).
As SLF (but always subsonic) I hope I can ask a question.
The registrations used by BA are clear in their origin - but for Air France, any particular reason for F-BVFx and F-BTSx?
thanks for the read. I think I've managed every single post (although I skimmed some of the *deeply* technical stuff).
As SLF (but always subsonic) I hope I can ask a question.
The registrations used by BA are clear in their origin - but for Air France, any particular reason for F-BVFx and F-BTSx?
ATC Watcher
it was possible - if the total route was short enough. And you had ~60000 kilos of fuel to waste.
Key points:
- Concorde's speed was directly related to altitude - going subsonic required descending to FL400 or below. With a corresponding decrease in Mach/true airspeed. Very poor fuel efficiency below Mach 1.7 - couldn't hold speed without afterburner/reheat. Don't forget how much Concorde's flight profile and range absolutely depended on turning the engine/nacelle system into a ramjet from Mach 1.7-2.02 to work "commercially" at all. The old "at Mach 2.02 cruise, 85% of the thrust came from the nacelle" idea.
- to get back to supersonic flight required repeating the whole climb-and-accelerate profile with AB/reheat fuel flowing by the tonne, until re-acquiring Mach 1.7 at FL400±.
which leads to:
Nope. It was far more efficient to simply maintain Mach 2.02 and bypass India (and Sri Lanka) to the south. Circling all the way around them while maintaining supersonic speed and altitude used less fuel than: descend - slow to subsonic - cross India on a direct route - climb and accelerate back to supersonic.
You can google up some maps of Concorde routes (e.g. Paris-Dakar, Dakar-Rio). Actual routes, not airline "schematics." And see that it was almost always preferable and more efficient to get out over an ocean ASAP and get the ramjet effect going at Mach 1.7+, and then stay out over water as long as possible. Even if it meant an indirect "dogleg(s)" route covering more miles. Except for some intentionally "transcontinental" routes like KHI-CCU, Perth-Sydney, Dulles-Dallas.
it was possible - if the total route was short enough. And you had ~60000 kilos of fuel to waste.
Key points:
- Concorde's speed was directly related to altitude - going subsonic required descending to FL400 or below. With a corresponding decrease in Mach/true airspeed. Very poor fuel efficiency below Mach 1.7 - couldn't hold speed without afterburner/reheat. Don't forget how much Concorde's flight profile and range absolutely depended on turning the engine/nacelle system into a ramjet from Mach 1.7-2.02 to work "commercially" at all. The old "at Mach 2.02 cruise, 85% of the thrust came from the nacelle" idea.
- to get back to supersonic flight required repeating the whole climb-and-accelerate profile with AB/reheat fuel flowing by the tonne, until re-acquiring Mach 1.7 at FL400±.
which leads to:
Did the BAH to SIN route involve slowing down over India?
You can google up some maps of Concorde routes (e.g. Paris-Dakar, Dakar-Rio). Actual routes, not airline "schematics." And see that it was almost always preferable and more efficient to get out over an ocean ASAP and get the ramjet effect going at Mach 1.7+, and then stay out over water as long as possible. Even if it meant an indirect "dogleg(s)" route covering more miles. Except for some intentionally "transcontinental" routes like KHI-CCU, Perth-Sydney, Dulles-Dallas.
Sounds like a topic for a new thread. If it's as good as this one I can't wait.
Also did they have the same fuel transfer complexity to maintain CoG during cruise
I think the canard were for low speed control and stability as I think they retracted for supersonic flight.
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There are various sources on the web that claim varying Mach/supersonic time restrictions for the the Pepsi-branded Concorde, mainly based on the inability/reduced capability of the dark livery to "deflect heat". This seems a bit strange given the black paint of the SR-71 and I'd appreciate comments by anyone in the know about this.
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This extract from Norman Harpur’s 1966 paper on “The Structure of the Concorde” explains it pretty well I think. Norman was the chief structures engineer on the British side so he can be classed as someone with definitive knowledge.
“At Mach numbers of about 2 it pays to paint the external surface white. Despite what the textbooks say, a white surface can be made almost as good as a black surface at radiating heat away from itself whereas it is much better than a black surface in reflecting solar radiation. Under these circumstances, at these speeds, a white surface will result in a cooling of something like 10 deg C. If we increase the speed of the aircraft, up to say a Mach number of 3, far more heat is transmitted by skin friction and the effect of solar radiation is relatively small. In these conditions it now becomes important to have the highest possible emissivity on the surface to reduce the heat as much as possible and here, even though relatively small, the gain between white paint and black paint is important. Therefore the Mach3 supersonic transport should really be painted black.
“At Mach numbers of about 2 it pays to paint the external surface white. Despite what the textbooks say, a white surface can be made almost as good as a black surface at radiating heat away from itself whereas it is much better than a black surface in reflecting solar radiation. Under these circumstances, at these speeds, a white surface will result in a cooling of something like 10 deg C. If we increase the speed of the aircraft, up to say a Mach number of 3, far more heat is transmitted by skin friction and the effect of solar radiation is relatively small. In these conditions it now becomes important to have the highest possible emissivity on the surface to reduce the heat as much as possible and here, even though relatively small, the gain between white paint and black paint is important. Therefore the Mach3 supersonic transport should really be painted black.
Would anybody be able to post a picture of one of the Pooleys sliderules developed specifically for Concorde operations? It was used for descent planning and is mentioned in the book Flying Concorde.