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Flash2001
10th Nov 2003, 04:58
Coupla questions on Concorde for those who know...

1: How loud was the sonic boom on the ground on track and at cruise?

2: How far either side of track could it be heard under average conditions?

3: At what points in altitude and distance travelled did it normally pass through mach 1?

4: During what parts of the flight regime was reheat used?

5: In a normal trans Atlantic trip, how much of its fuel had it consumed to get to cruising altitude?

Like most of us I'm sorry to see it go. Worse is that with no replacement, the many lessons learned cannot be applied. The knowlege is lost.

After an excellent landing you can use the airplane again!

Whispering Giant
10th Nov 2003, 05:43
Flash2001

In answer to 1 of your question's - Concorde used reheat on takeoff to about 1000ft and then again when accelerating to and through mach1 and was again switched off once mach1.7 was reached whereby 100% raw engine power was used - reheat was only needed to get through the high resistance area around mach1.

Mach1 had to be reached or passed by 100miles off the coast, in the UK this was 100nm off the coast at Coombe Martin on the north coast of Devon on one of the SST tracks across the Atlantic -in the USA the accelaration point was just off the coast of Nantucket Island, normal altitude that mach 1 was passed was between 30000-45000 ft it would varie each day depending on the outside air temp.

Hope this answer's a couple of yr questions

rgds
W.G

Skylion
10th Nov 2003, 06:56
When Concordes supersonic audiability was being checked by Capt John Hutchinson in Port Dickson Malaysia due to complaints that it was rattling windows and waking people up there while still supersonic over the Straits of Malacca en route into Singapore the verdict was that the sonic boom, having gone directly downwards from the aircraft then spread up to 20 miles each side. The noise depended on atmospheric conditions but in an area familiar with tropical thunderstorms even the worst booms were hardly shattering,- more a dull thud than a crack. The loudest complainer,- almost the only complainer,- was an elderly Brit. By edging slighly further out into the Straits to avoid Port Dickson the only known recipients of the boom were the staff of a lighthouse in Indonesia, and they didnt seem fussed at all.

fritzi
10th Nov 2003, 07:31
At what points in altitude and distance travelled did it normally pass through mach 1?

Mach 1 is achieved at around 32,000 ft.

Concorde cant be less than Mach 1 at 45,00 feet if you want to fly efficiantly.

reheat was only needed to get through the high resistance area around mach1

Afterburners are required to be used from around M0.96 to M1.7

BizJetJock
10th Nov 2003, 07:35
Having several times been underneath Concorde whilst on a boat, the "boom" is like someone firing two shots with a .22 rifle just behind your ear:ooh:
Much as I love Concorde as a technical achievement, I can understand why they didn't let her go supersonic over land.
BTW, the development cost in today's money was only about twice what's just been spent on on Bush/Blair's adventure in Iraq so far - I know which I'd rather have my taxes spent on:mad:

Taking Over, Nigel
10th Nov 2003, 13:07
How many naieve articles have I read over the last umpteen years about successors to the mighty Concorde?!
However the reality is that there will be successors ONLY if they are more efficient than 747's & A 380's etc (not likely with today's technology.)
Why MORE efficient?? - because of the humongous development costs. Yes, I know wars cost a lot- but no tax payer would allow their government to spend that sort of money developing an aeroplane. And no aeroplane company would spend the money unless guaranteed success.
Just like I don't think man will walk on the moon again. Too expensive!
Sadly, the Concorde is permanently dead.
:(

Flash2001
11th Nov 2003, 03:44
Efficient?

Yeahbut...

If an SST saves 2.5 hr on a trans Atlantic crossing and a ticket costs $5000.00 more than first/business then it is efficient for anyone whose time costs more than $2500/hr to use it. There are quite a few people around who meet that requirement.

Would that I were one!

After an excellent landing you can use the airplane again!

paulo
11th Nov 2003, 05:56
Ahem: "Concorde Uses" not "Concorde Used",etc. Not over yet dear chap.

(Although with today's departure, maybe the noise abatement procedure is a thing of the past. :ok: )

Bellerophon
12th Nov 2003, 00:16
Flash2001

1: How loud was the sonic boom on the ground on track and at cruise?

Ever so quiet! :D You could hardly hear it at all! :D

The intensity of the boom depended on many factors. If youíve ever been on a boat when she passed right overhead, at around 32,000 ft, shortly after starting to accelerate, then that was probably as loud as it got. I havenít, and have heard varied reports from those who have.

I have been on a boat when she has passed not to far from overhead, around 57,000 ft shortly before decelerating, most of the passengers thought it was the dull rumble of distant thunder.


2: How far either side of track could it be heard under average conditions?

35 miles away was reckoned to be boom free.

In supersonic flight Concorde trails a sonic boom behind her throughout her flight, and the rough dimensions of this boom carpet are 20nm wide (10nm either side of track) by about 15nm long, and extending all the way down to the ground.


3: At what points in altitude and distance travelled did it normally pass through mach 1?

At transatlantic weight, she would climb at her VMO of 400 kts IAS, and would therefore reach M1.0 climbing through 28,500 ft. The distance down range could vary considerably, but at best would at least 70 nm out of BGI, and could be considerably more out of LHR and JFK.


4: During what parts of the flight regime was reheat used?

From start of take-off roll to end of noise abatement, typically 80 seconds, and again during the transonic acceleration, from M0.93 to M1.70, typically 10 minutes.


5: In a normal trans Atlantic trip, how much of its fuel had it consumed to get to cruising altitude?

Around 40% of the trip fuel will be used in the first hour of flight.


fritzi

Concorde cant be less than Mach 1 at 45,00 feet if you want to fly efficiantly.

Correct, in fact Concorde cannot fly subsonic at 45,000 ft, period.


Whispering Giant

Mach1 had to be reached or passed by 100miles off the coast

The speed control points were not quite as restrictive as that.

On departure from the UK, the acceleration commenced at UPGAS, a position in the Bristol Channel only about 7 miles from Porthcawl, with the aircraft being supersonic fairly quickly thereafter.

On arrival into the UK, in Summer, the speed limit point was only about 35 miles from the Devon coast (Hartland Point), although it did move further out in Winter.

Regards to all

Bellerophon

Tinstaafl
12th Nov 2003, 04:15
Can't fly subsonic below FL450? That's fascinating. That's its equivalent of a low speed buffet boundary at that level?

Flash2001
12th Nov 2003, 05:55
Thank you gentlemen for your courteous and informed replies. I am having a little trouble rationalizing the crack of a .22 fired behind my ear with the rumble of distant thunder unless, of course, the .22 is fired at my ear in which case the question does not arise.

One additional question: In what part of the flight regime was Concorde behind the power curve?

After an excellent landing you can use the airplane again!

Tinstaafl
12th Nov 2003, 06:19
Flash, it depends on how quickly over time AND distance the sudden rise in pressure occurs, and again for the sudden drop.

A bullet has a very sudden rise over a very small distance, holds that high pressure over the very small lenght of the bullet, then the sudden drop in pressure. We hear that as a 'crack'.

I suspect in Concorde's case there's a fairly large difference in distance & time - comparatively speaking - so there's a less 'steep' rise in pressure, a noticeable delay then a less steep drop in pressure leading to a double 'boom'.

jrbt
12th Nov 2003, 08:28
When I (brag on) flew Concorde JFK-LHR 28 October 1986 as a courier for $250 (brag off), the windows measured about 3x4 inches. In one recent photo of Concorde interior I see the windows are much bigger than that. Were they enlarged, perhaps during the 2000-2001 refitting? Or did some Concordes have larger windows than others?

Flash2001
12th Nov 2003, 21:54
No Free Lunch

Yes, of course the spectral distribution is bound to be different. You don't hear much "Snap" from lightning at 12 or 12 miles. That's why I questioned the comparison to the .22.

After an excellent landing you can use the airplane again!

jrbt
13th Nov 2003, 01:35
My correction Paulo (ahem): *do* some Concordes have larger windows than others?

BahrainLad
13th Nov 2003, 02:00
<I think on>

That the prototypes 001/002 had windows approximately the same size as the 707.

However, the airline service (and I think the pre-production) models, i.e. the ones that you would have flown on, have much smaller windows, roughly the same size as my hand <brag on> tested on 08 Sep 2003, LHR-JFK BA001 <brag off> or the front cover of a paperback book.

This change was effected due to the requirements of descending in case of a window breakage from FL 58 down to a safe altitude. Smaller windows means that the air in the cabin escapes slower, and gives more time for an emergency descent to be completed. Quite a good reason, wouldn't you agree?

<I think off>

Bellerophon
13th Nov 2003, 07:23
Tinstaafl

Can't fly subsonic below FL450?

Well, we always tried to on landing, but I think I know what you mean! ;)

That's its equivalent of a low speed buffet boundary at that level?

Yes, in effect. Using the more traditional 1.3VS as a minimum speed in cruise would not be particularly relevant or useful on Concorde, and in fact VS is difficult to determine.

Instead, Concorde uses a speed called VLA (Lowest Authorised Speed) as her minimum speed for any stage of flight, and at FL410 her VLA is 300 kts IAS, which means that she must be at or above M1.0 to fly above FL410.

In practice, passing FL450 in a climb she would be nearer M1.8, with an IAS of 530 kts, some 230 kts above her minimum speed, not a bad margin!

Regards

Bellerophon