Slightly O/T? Speed....

Left LHR on Thursday night (11/1/07) on VS350 to Mumbai. We took off 35 minutes late at 22.20 and once airborne Captain warned of turbulence as far as Germany.

As we motored along (turbulence not too bad) I noticed we were touching speeds of 652mph (1,043km for those younger viewers[:p]).

We touched down in Mumbai at 11.45 (25 mins early), a net 1 hour gain on flight time. Is this "speed" pretty fast? Anyone experienced faster times? What is (if any) maximum speed of an aircraft + tailwind?

I noticed the return flight (VS351) left 30 minutes late and including this delay was about a net hour late on scheduled return time - headwind kicked in on way back I guess[|:)]

[preiffer]

I've been at 700mph ground speed a few times, with a 100+ tail wind. The aircraft will max out at Mach .086 ish, so anything over that speed (changes on any given day) will always be due to heavy winds.

Thanks for that.

Just had a look at a web site:

http://www.globalaircraft.org/converter.htm

Apparently Mach 1 at 40,000 feet is @660mph (ground speed).

We were at 39,000 feet which equates to .99 mach.

Not that you would know (being in the air[:w]), but presumably at 700mph+ there was/is a sonic boom?

I got to 700+ when travelling bck from JFK on a BA 747. This was due to 100+ tailwinds from hurricane Wilma. We escaped Florida just in time!!

[preiffer]

It all depends on the day, though. Mach 1 at FL400 on a standard ISA day is 660 - but I believe that will change dramatically with temperature changes also.

Also, bear in mind - was it 660kts or 600mph? (a mile is less than a knot)

Having read the title, I was going to suggest that this topic would be more suited to the new OT forum[:w]

I know yachts have a max speed based on the lenth/design of the hull (I'm sure Jeremy could elaborate); do a/c have the same effect whereby they cannot go over a certain speed no matter how much the extra force is?

VS.

Originally posted by preiffer
I've been at 700mph ground speed a few times, with a 100+ tail wind. The aircraft will max out at Mach .086 ish, so anything over that speed (changes on any given day) will always be due to heavy winds.

By the way, I believe it's .86 mach. .086 is quite slow. [y]

[preiffer]

Good point Nick. Oh, the slip of a zero... [:I]

Depending on how accurate flight sim 2004 is, i think that if a 747-400 goes much over mach 0.90 it will become very unstable and the nose will start to 'nod' up and down.

Like i said though, it could just be on fs2004 that it does this. Not totally sure if a real 747 would do this.

[preiffer]

Well, by the look of it - at least one VS 747 has made "waves"... [:0]

[Scrooge]

Originally posted by preiffer
Well, by the look of it - at least one VS 747 has made "waves"... [:0]

Nice find [y]

Originally posted by KenUK
Thanks for that.

Not that you would know (being in the air[:w]), but presumably at 700mph+ there was/is a sonic boom?

It all gets very complicated, but the fact is the aircraft is not traveling at 700 mph in the air, that is the ground speed, you need to take what ever ground speed the aircraft is doing then add or subtract the speed of the air stream the aircraft is in.

Originally posted by hairy114
Depending on how accurate flight sim 2004 is, i think that if a 747-400 goes much over mach 0.90 it will become very unstable and the nose will start to 'nod' up and down.

Like i said though, it could just be on fs2004 that it does this. Not totally sure if a real 747 would do this.

FS is not all that accurate, posky puts out some pretty good models, but they still have a number issues with the flight modeling.

Just a silly fact (and pretty well known) a 747 SP N4522V did go supersonic, but it was in a dive and the aircraft did sustain structural damage.

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