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jumpseatflyer
Topic Author
Posts: 155
Joined: Fri Sep 23, 2005 12:13 pm

V1 is the "commitment speed," at which the plane becomes obligated to fly.

My question:
What if the runway is extremely long, and the a/c in question, say a 737 [I know I'm probably hinting towards a 3 mile runway], has enough room to safely stop even well after the descision speed? If such is the case, what is the point of V1?

In other words, if there is a formula that factors runway length into the descision speed, what is it?

Thanks.
-Paul, down here at the young folks home

BDKLEZ
Posts: 1803
Joined: Sun Jun 26, 2005 11:57 am

 Quoting Jumpseatflyer (Thread starter):V1 is the "commitment speed," at which the plane becomes obligated to fly

Actually, you should more clearly define V1 as "decision speed" as this is the point at which if there are any difficulties with the take-off roll, then the a/c will be able to successfully stop before reaching the end of the runway. The pilots then have only a few second to make that "decision" to continue with or abort the take-off.
Trespassers will be shot; survivors will be shot again!

Derik737
Posts: 264
Joined: Sat Dec 11, 2004 5:53 am

 Quoting Jumpseatflyer (Thread starter):What if the runway is extremely long, and the a/c in question, say a 737 [I know I'm probably hinting towards a 3 mile runway], has enough room to safely stop even well after the descision speed? If such is the case, what is the point of V1?

Also remember most takeoffs are not full-thrust. Airlines derate takeoffs based on temperature, runway length and conditions. So even on a long runway, you may eat a lot of it up.

FlySSC
Posts: 5334
Joined: Tue Aug 12, 2003 1:38 am

 Quoting Jumpseatflyer (Thread starter):My question: What if the runway is extremely long, and the a/c in question, say a 737 [I know I'm probably hinting towards a 3 mile runway], has enough room to safely stop even well after the descision speed?

V1 is calculated according to many factors : weather, Runway conditions, weight, wind direction/force, outside temperature, etc ...

The case you decribe is very frequent on big airports : an A320 or a B737 or an ATR42 taking off from a 3900 meters Runway ...

In that case, V1 = VR most of the time ... which means that the pilots can abort the take off until the very end of their take off run.

HT
Posts: 5864
Joined: Sat May 07, 2005 6:20 am

Attention ! Pun !

"V1" is a Fieseler Fi103 which itself did not have a "V1"-speed
http://en.wikipedia.org/wiki/V-1_flying_bomb
http://www.luftfahrtmuseum.com/htmd/dtf/fi103.htm
http://www.kheichhorn.de/html/body_fieseler_v1.html

Apart from my unfitting answer, the initial post might have been better off in forum "tech&op´s" ... ?!

Have fun,
-HT
Carpe diem ! Life is too short to waste your time ! Keep in mind, that today is the first day of the rest of your life !

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