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Post by graham on Sept 25, 2021 9:05:30 GMT
Would anyone know what track the morning BA Concorde flight to Dulles would have taken over southern counties please? We used to hear the boom at precisely the same time every morning and that was confirmed by a friend of my dad's who worked in the tower at Lyneham in the mid/late 70s.
But, on another forum I use, someone's telling me "impossible, the plane only went supersonic over water". As I understand it, the boom cone could extend outwards from the plane by as much as 50 miles and there's plenty of water west of Wiltshire within a 50 mile distance.
Can anyone shed any light please?
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Post by rh226 on Sept 25, 2021 11:28:54 GMT
Hi Graham,
IIRC, Concorde used to depart Heathrow and head West along Green 1 to LA (Lyneham). There it would depart airways and route direct down the Bristol Channel to point "Merlin" (now = MERLY ??) before going oceanic.
The other forum is correct in that supersonic flight was only permitted from about "Merlin" onwards, by which time Concorde would be climbing through FL440 or thereabouts. However, you are correct in that the cone can extend, and be heard, to quite a distance, Quite how far often depending on weather conditions at the time.
Bob
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Post by graham on Sept 25, 2021 11:52:38 GMT
Cheers Bob, I know it's what we heard every morning, I believe the IAD flight departed LHR at 10.30am and then passed over us slightly to our north. I've just read that the boom cone would extend approximately one mile for every thousand feet of altitude.
It was quire eerie as the birds would all stop chirping and then, you would hear the boom about ten seconds later.
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Post by Jeff on Sept 25, 2021 12:02:10 GMT
Would you hear the boom if it was created after passing you, doesnt the cone of sound travel forward?
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Post by michael on Sept 25, 2021 12:11:17 GMT
Graham,
It is so long since I had to know this information for my West End S5/S23 level planning at Wesr Drayton as well as flight Planning
the route was something like
N0550F260 CPT L9 MALBY DCT C/KESUP/N0740F280F430 DCT MERLY DCT LESLU NATSM C/5041N01500W/M200F450.
The route a seen was usually for acceleration at 15W but not being a controller can't remember if they accelerated from MERLY (Position roughly south of STU in the Bristol Channel,so long now
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Post by graham on Sept 25, 2021 12:55:15 GMT
Cheers Michael, could you put me in touch with an interpreter please to decipher your post? ;0)
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Post by graham on Sept 25, 2021 12:56:54 GMT
Found this online...
The bigger and heavier the aircraft, the more air it displaces. The shock wave forms a cone of pressurized air molecules which move outward and rearward in all directions and extend to the ground. ... The sharp release of pressure, after the buildup by the shock wave, is heard as the sonic boom.
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Post by michael on Sept 29, 2021 22:28:56 GMT
Graham, It is so long since I had to know this information for my West End S5/S23 level planning at Wesr Drayton as well as flight Planning the route was something like N0550F260 CPT L9 MALBY DCT KESUP/N0740F280F430 DCT MERLY DCT LESLU NATSM 5041N01500W/M200F450. The route a seen was usually for acceleration at 15W but not being a controller can't remember if they accelerated from MERLY (Position roughly south of STU in the Bristol Channel,so long now Sorry Graham,
Old habits Standard Flight Plan
From Heathrow after departure 550knots request FL260 via CPT (COMPTON) LIMA9 DIRECT KESUP (/ = after passing KESUP ACCELERATE TO 740Knots between FL280 to FL430 direct MERLY direct LESLU Nat Track SM 5041N 15W/ MACH 2 FL450
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Post by graham on Sept 30, 2021 6:50:56 GMT
Thanks Michael!
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