Documentary on Concorde on C5

[Russell]

There is a 2 part documentary on Concorde, talking to designers, engineers, politicians, etc on Channel 5.  First part was the other night.

I found it interesting and it had some new information that I was not aware of.

Can anyone expand on the novel, and if the documentary is to be believed unique, air intake ducts that allowed it to cruise at supersonic speeds without afterburners - known as super cruising.  The inlet ducts provided up to 60% of the thrust at supersonic speeds.  No other aircraft, even today, has this capability we were told.  Why??

Cue anecdote of Tornado pilot requesting permission to perform an intercept only to be left behind despite being on afterburners!

[pcolbeck]

The super-cruise thing is bollocks. Well there definition of it was correct and Concorde does have it but it wasn't the first or last aircraft to have it. The English Electric Lightening was the first and others include:

SR-71 Blackbird
Dassault Rafele
Eurofighter Typhoon
SAAB Grippen
SU-35

Its not common but it's a well understood technology that's been deployed where needed, mainly to give fighter better loiter time.

[Jakob W]

Super-cruise in general requires an airframe with low amounts of transonic and supersonic drag, and engines with decent amounts of dry thrust and reasonably efficient intakes under super-cruise conditions. What Concorde had was highly optimised components for all of these: in particular, the intakes' control system varied the geometry depending on the flow conditions to set up a system of shocks in the intake ducts; this decelerated the flow smoothly to subsonic conditions at the engine compressor face. Such an elaborate system was only really feasible in a large aircraft, and was only worthwhile for an aircraft that needed to cruise for large amounts of time at high Mach numbers, so I think Concorde was the only type to use something like this in service. (I think the B-1A bomber originally had complex moveable intakes, but when it was redesigned as the B-1B they were deleted.)

[spesh]

You're correct on the B-1A having variable-geometry intakes - the ramps were taken out and replaced by serpentine ducts which hid the compressor faces as part of the efforts to reduce the aircraft's radar signature when the B-1 program was resurrected by the Reagan administration.

However, Concorde was not the only type to use variable internal inlet ramps:

F-15:
http://www.f-15e.info/joomla/technology/engines/100-air-inlets

F-14:
http://www.anft.net/f-14/f14-detail-airintake-07l.jpg
https://combatace.com/applications/core/interface/imageproxy/imageproxy.php?img=http://www.anft.net/f-14/f14-detail-airintake-01.gif&key=fa18d0e9ac390fdef27e7750f39a0f3fbc80a95fb1f92b63740963b4854b94ba

Tornado:
https://c1.staticflickr.com/2/1513/23794698270_031aedd59c_b.jpg
http://www.b-domke.de/AviationImages/Tornado/Images/Tornado_GR4_ZA543_6751.jpg

[Jakob W]

Hmm, I'd thought the Concorde system was proportionally  much larger compared to the F-14 and F-15 intakes, but looking at the layouts I can find online it doesn't actually seem to be that much bigger. I wonder what it was that made the difference, then - just that it didn't have to be usable at high AOA as well, the nice clean underwing location, or something else?

[spesh]

Everything was optimised for supercruise - the engines were at their most efficient at 2.0 Mach and 18,000m altitude, the fuselage had a high fineness ratio (length/width) and the ogival wings had high lift/drag. Also, the trim was adjusted by transferring fuel to shift the centre of gravity, instead of setting aerodynamic surfaces (trim tabs) which would have increased drag.

https://en.wikipedia.org/wiki/Concorde#Range

[cygnet]

Yet again this forum provides excellent distillation of the science stuff.

[Jakob W]

Agree on the total airframe optimisation, but from what I distantly remember from my propulsion lectures, the Concorde intakes were particularly efficient even for a VG system - a quick Google suggests 94% or so pressure recovery?

[fuzzy]

I loved the comment from the chief boffin along the lines "Anyone can go supersonic if you throw enough money at it- except the Americans" at which point, the corners of his mouth may have twitched slightly into a bit of a smirk