View Full Version : probably a daft question...
bluekangaroo
12th Dec 2008, 22:06
but as i am scared of flying, i would appreciate some comments?
was on a flight today and while crossing the Atlantic, the plane hit some turbulance-this was scary, but worse was looking at the flight data on the screens showing ground speed of 705mph-tail wind 170mph. Seemed like the plane was going way too fast (hope this doesnt sound daft)-is this normal as it scared the life out of me that it could go so fast as it normally seems to be between 5-600.
again, apologies if its a daft question
Rainboe
12th Dec 2008, 22:54
It's not that unusual across the Atlantic to be sitting in a jetstream of over 200mph, sometimes even 200 knots which is about 230mph. It will probably be completely smooth. Aeroplanes try and make use of these jetstream winds to reduce fuel requirements, and avoid them coming the other way. Gogle jetstream winds and read all about it.
Seemed like the plane was going way too fast (hope this doesnt sound daft)
The plane isnt going that fast, picture the airport moving walkways, if you walk at a certain speed on a walkway, you will get to the end faster. The wind is like the moving walkway!
Mutt
G SXTY
13th Dec 2008, 08:33
The aeroplane's speed across the ground is pretty irrelevant in terms of performance (although it matters in getting you to your destination on time!).
What matters is its speed through the air. If the airmass its travelling in is already moving at, say, 200mph, then you have 500 + 200 = 700mph, and everyone gets there early. The faster the better. :ok:
Aeroplanes will seek out tailwinds and try and avoid headwinds, for obvious reasons.
manintheback
17th Dec 2008, 13:04
A query on the above. At cruise of say 36000ft and speed in excess of 700mph with a 200mph+ tail wind are you knocking on the door of the sound barrier and supersonic flight?
The tail wind doesn't make a difference as we measure the speed in relation to the air the aircraft is moving through. The analagy of the moving walkway is a good one, but you have to ignore the fact on a moving walkway you would encounter more air resistance, it doesn't work like that in an aircraft as the air is also moving. Hope this helps.
Tim_CPL
17th Dec 2008, 17:11
You'd only be supersonic if you airspeed was >600MPH (or whatever the speed of sound is at that ALT and TEMP). You airspeed is 500MPH, and your speed over the ground is 700MPH, so no, you are not supersonic.
Hi from a fellow previous scaredy-cat passenger!
There is no such thing as a daft question, just a daft answer! If you're nervous as I was, then ask questions. You'll find plenty of superb help on this site.
Can I direct to a fab website I found when I first flew after a ten year break and as I landed I vowed I'd never fly again ... which I had to do otherwise I'd have never got home!
www.flyingwithoutfear.com (http://www.flyingwithoutfear.com)