Quax .95
March 12, 2011, 21:49:00 GMT
permalink Post: 6302637

The engine starting sequence was also in airline operation 3-4-2-1. At the gate the altered sequence was 3-2 prior the pushback and 4-1 after due to safety reasons for ground crew and for noise restrictions at some airport stands.

Brit312 explained in post #140:

Quote:

Yes we always started just the two inboard engines prior to push back and the outers when the push back was complete. This was for a number of reasons, but I do seem to remember it was not unheard of to break the tow bar shear pin on the initial push, so the less power the better

Remember that Concorde had no APU and no across the ship ducting for stating engines, therefore prior to push an air start unit was plugged into each pair of engines and the inboard engines would be started. This allowed, after push back, air from each inboard engine to be used to start it's outboard engine.

The other good reason for starting the inboards prior to push was that with no APU the cabin temp would rise quite quickly [specially in places like Bahrain in summer] and never mind the passengers
comfort, but some of M2dude and ChristiaanJ fancy electronic equipment was very temp sensitive , especially those intake control units down the rear galley. With Two engines running we could use their bleed air to at least try and hold the cabin air temp during the push back

I must admit that I am no expert (not yet

), but it seems both sequences follow the logic to feed the blue hydraulic by engine#3 first, then one of the two yellow systems (2 or 4) and the green hydraulic (engines 1&2) which supplies power to some more services than the blue (droop nose and visor, landing gear, main wheel brakes with anti-skid and nosewheel steering).

Well, I hope, this was not a stupid answer before I took a chance for a nonstupid question

- but I am so exited about this thread and just want a little bit to give back!

Thanks for the probably best thing ever I have found in the internet. Thank you M2dude, Brit312, ChristiaanJ, Exwok, Bellerophon, Landlady et al.!

Subjects APU (Auxiliary Power Unit) Anti-skid Bleed Air Braking Cabin Crew Galley Hydraulic Intakes Landing Gear Visor

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Quax .95
April 06, 2011, 19:43:00 GMT
permalink Post: 6354590

Hello skyhawkmatthew!

M2dude gave a good answer on your question in post #1085, so I think I may quote this here again.

Quote:

Originally Posted by M2dude

As far as the MAX SPEED bit goes, Concorde was as we know flown to a maximum of Mach 2.23 on A/C 101, but with the production intake and 'final' AICU N1 limiter law, the maximum achievable Mach number in level flight is about Mach 2.13. (Also theoretically, somewhere between Mach 2.2 and 2.3, the front few intake shocks would be 'pushed' back beyond the lower lip, the resulting flow distortion causing multiple severe and surges).

The maximum altitude EVER achieved in testing was I believe by aircraft 102 which achieved 68,000'.

Subjects AICU (Air Intake Control Computer) Engine surge Intakes N1 (revolutions)

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Quax .95
April 07, 2011, 20:56:00 GMT
permalink Post: 6356891

Not quite right: the reheats ignite if

The N1 of number 4 engine is limited to a maximum value of 88% up to 60kts, thus within the operational requirements of the reheat.
(At temperatures colder than -35\xb0C the engine control schedule limits the N1 of all engines to 88% or less.)

Quote:

Originally Posted by Brit312

Up to 60 kts the F/E could reselect a failed reheat so hoping it would be OK by 100kts

Regards

Last edited by Quax .95; 11th April 2011 at 16:34 . Reason: T/O-case added

Subjects Afterburner/Re-heat N1 (revolutions)

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Quax .95
April 07, 2011, 22:15:00 GMT
permalink Post: 6357012

This might be because the #4 engine accelerates less fast than the others due to the limiter, reaching 81% N1 a little bit later. But this thread is too brilliant for presumptions (don't want to repeat the mistake of my first post...

). Let's see what the Concorde-geniuses add.

Last edited by Quax .95; 8th April 2011 at 23:53 . Reason: spelling

Subjects N1 (revolutions)

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Quax .95
May 12, 2011, 10:18:00 GMT
permalink Post: 6445737

Quote:

Originally Posted by M2dude

You would not wind up on the brakes either, the carbon brakes were extremely sensitive to overtorquing.

Looking at the pic of G-BOAB in the detuner brings me to the question how they performed the run-up. No brakes, just chocks?

Subjects Braking G-BOAB

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