I realize this thread is two years old...but I just came across it and would like to clear up some of the misconceptions here about what causes the high amount of thrust produced by the Concorde inlet duct...
I’ve also just come across this thread after two years, and although I for sure don’t want to repeat any of the millions of electron-volts expended in the excellent discussions I thought it might be of interest to have some additional comments ‘from the inside’.
The first thing I would like to say is that we always thought of the total system as “powerplant”. As in any aircraft powerplant (engine) the forces on the various components vary – some produce drag, others thrust. Part of the intake had a thrust component, part had drag. Similarly with the engine itself and the propelling nozzle. It is really a bit misleading to say that “the intake produced thrust”. For us it was just one component of the powerplant that gave a thrust .- and we weren't particularly bothered whether that came from pressures on the diffuser walls or momentum changes, What mattered for us was that the intake efficiency (pressure recovery and intake external drag) was as high as possible. (not intake drag as high as possible of course). I can't stress too highly that the powerplant had to be considered a
s a whole!
Dude’s remark:
The important concept to grasp is that you have to consider the powerplant as the 'engine' if you like. It's the intake, engine and nozzle assembly that were able to work together in such perfect harmony, but each component was totally codependant on the others.
was absolutely on the mark. Other things I found interesting:
Post #15 B377
Wonder how much of this was learned from the use of the 593s on the 1950s Victor bombers albeit these were not supersonic?
Not a lot!
Post #31 Landroger
The whole concept of 'Supercruise' is quite stunning and the thought occurs; was it played for, or a happy outcome of the way the design froze?
Very definitely played for !
You are saying though, that it could not maintain Mach 2 without reheat
Yup!
Post # 33 M2Dude
The problem was that having decided that an analog intake system would never be able to provide the level of control and stability required for certification, the technology almost had to be invented. In 1970, when relatively late on, in project definition terms, it was decided to use 'throw 'away' the analog system and replace it with a completely new digital one, there came a problem; there was no such thing as an airborne digital control system, and so one had to be 'invented' in Bristol.
The analogue system wasn’t thrown away exactly – we retained the inner ‘analogue’ system that did the closed loop dynamic control of ramps etc. and wrapped a digital system around it to define the control ‘laws’ to which the intake operated.
Post #39 Mr Optimistic
Of course you would need 10^-9 now, don't suppose safety was quite the game it was now.
Actually Concorde was the first civil aircraft to be certificated using this 10^-9 approach, although the rules were of course contained in TSS Standards not enshrined in FARs. Also we adopted a far more pragmatic ‘engineering’ way of working than the almost blind faith in numbers that seems to be the case today!
Post #56 M”Dude
For a supersonic aircraft, how good your whole 'engine' in this context is relies on solely how well designed the 'front bit', the 'rotating middle bit' and the 'back bit' are, and how they work together. Weakness in any one of these three is gonna cost you performance and/or fuel (and trans-Atlantic range is just not possible; ask Tupolev).
Post #66 Pugilistic Animus
and it illustrates that the Great Art of Aerodynmics is Experimental - a little twist here a little waxing and polishing,..., a little area cut away from there...and it---- Still Flies
Ain’t that the truth!
Post #56 again
And all this done with slide rules, protractors and the backs of hundreds of cigarette packets, without any mathematical modelling in sight.
Also true, but only two of the team smoked (mind you they made up for the others)
Post #67 M2 Dude
If I may, I would now like to mention the 'some oil lamps and diesel oil' story.
True, but we also did the ‘Hi-tech’ bit. I thought people might be interested in the actual flow visualisation results we got from the lamp black and diesel fuel trick:
Post #100 M2Dude
The next part is pure comic opera; MBB then approach BAC for financial compensation with regard to this copyright infringement, (yep!! BAC design and develop the Concorde intake, give all the necessary knowledge and 'know how' to MBB for the Tornado and then are required to PAY THEM for the pleasure??).
but there is a bit of poetic justice; the final Tornado intake was a very poor design, with excessive levels of fuselage boundary layer ingestion and shockwave control.
In fairness to MBB, one should say that the Tornado had conflicting design requirements in that there was a need for efficient subsonic performance to give loiter (CAP) endurance, so they were forced to compromise a bit on the purely supersonic efficiency.
Hope I haven’t hogged too much space!