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View Full Version : Max speed for Concorde!

Diesel8
15th Aug 2004, 21:02
I think normal cruise was 2.02 there abouts, but was wondering what the max speed attained was, during testing or preproduction!

Thanks

Milt
16th Aug 2004, 03:27
Max IMN, CAS and TAS achievied in a Concord.

Interesting question.

Peter Baker if you see this you should know.

And what were its g limits and could you monitor for max skin tempertures during cruise.

dudduddud
16th Aug 2004, 06:22

The Max Speed was limited by the Max skin temperature of the tip of the nose protrusion. 126 degrees C.

Old Smokey
16th Aug 2004, 07:09
IF dudduddud is correct in quoting 126°C as imposing the upper speed limit (I have no way of knowing otherwise), AND there were no other CAS / Mach No. limits, -

At and above the Tropopause (11000 M / 36089.2 Ft) and at ISA Temperature (-56.5°C), a TAT of 126°C translates to M 2.0522 and a TAS of 1177.3 Kt. The associated CAS will depend on the particular Flight Level, and as a sample -

F/L 450 = CAS 716.3 / EAS 518.0
F/L 500 = CAS 650.7 / EAS 459.4
F/L 550 = CAS 589.1 / EAS 407.3

Temperature deviation from ISA will, of course, change these values.

John Farley
16th Aug 2004, 11:17
I think this has cropped up before and a search might help.

I have no personal knowledge of the details but would make two comments

Certification normally needs to see speeds 10% above those cleared for service, plus the temp limit would only apply once the thing had hot soaked up.

If you hung around slow at height to cold soak it down before a dash you would be more likely to reach some other chosen limit before the skin temp got in the way

SR71
17th Aug 2004, 08:13
Old Smokey,

T_0/T=1+(\gamma-1)/2*M^2.

I concur.

I've always wondered what the max Mach of the SR-71 was. The limitation was a CIT (Compressor Inlet Temperature) of 427C. I calculate that with ISA-50C, using the same equations Mach 4 was possible.

The flight manual (http://www.sr-71.org/blackbird/manual/5/5-8.htm) lists Mach 3.2 as the design flight Mach number but in the book "The Untouchables", flight crew record seeing in excess of 3.5 on an operational sortie in exactly the circumstances I describe.

Richard Graham describes the problem with the SR-71 (on Pg 167 of "The SR-71 Revealed - The Inside Story) with different ISA devs.

I've seen ISA+21C and <ISA-20C so maybe one day, somewhere, it saw M~=4.

:ok:

northwing
24th Aug 2004, 22:11
The limits at the top end were 530 knots CAS, M2.05 or T1=400 deg K (=127 deg C) At least, that was what they were when I worked on it in the late 60's. I seem to remember that the T1 limit stopped you getting M2.0 if the temperature was warmer than about ISA + 5 deg C, but you can work it out from the 1+0.2M^2 formula. From memory I think they had one of the prototypes up to M2.075, possibly faster.

farqueue
26th Aug 2004, 20:23
SR71, I read of a study to see what the ultimate limit was, and it was M3.5 +- a bit. This was where the temp on the centre of the windscreen was so high that there was reduction of strength on the seal/mounting.

Don't think I want it getting that friendly :) Sorry I can't remember where I saw that. Mary may know.