Winglets
04-04-2008, 04:34 PM
#2
Line Holder
Joined APC: Apr 2007
Position: my desk, studying
Posts: 29
04-04-2008, 05:02 PM
#3
Gets Weekends Off
Joined APC: Jul 2007
Position: C-17 bunk/in the kiddie pool
Posts: 216
Yup, CCX beat me to the punch, 9' winglets on the C-17.
Fuel is definitely a problem in the military. I have seen a 180 in regards to fuel planning for a typical mission. They are much more concerned (as they should be) at saving fuel. Before prices went high, you could pretty much get away with anything, with only the weakest of excuses. Lately they have been holding our feet to the fire more and more on landing with excess gas.
Fuel is definitely a problem in the military. I have seen a 180 in regards to fuel planning for a typical mission. They are much more concerned (as they should be) at saving fuel. Before prices went high, you could pretty much get away with anything, with only the weakest of excuses. Lately they have been holding our feet to the fire more and more on landing with excess gas.
04-04-2008, 06:31 PM
#4
Moderate Moderator
Joined APC: Mar 2008
Position: Curator at Static Display
Posts: 5,681
Whitcomb Winglets & Fighters
Mmaviator:
They could be used---but there is no reason to.
Winglets are used on civil jets because they give part of the benefit of a longer wingspan and therefore higher aspect-ratio. Think "High-aspect" like a high performance sailplane. Longer wings mean less energy loss to wingtip vortices.
However, long wings mean a longer lever trying to break the wing off at the wingroot. That means you have to build your wing stronger--and therefore, heavier.
Winglets give some of the increase in apparent "span," but with less bending-moment.
Fighters:
Since the wings of fighters are generally built for strength anyway (most modern fighters allow up to 9 g, which means they are built to a 13-g ultimate strength), the small gain in efficiency in level-flight is offset by the increase in weight. Weight is a performance-killer in a dog-fight.
Plus, the drag of external weapons, whether they are missiles, bombs, or self-defense jammers, is a far greater variable than the meager savings by using winglets.
Winglets would also make a bigger radar signature, which means easier detection by the enemy.
They could be used---but there is no reason to.
Winglets are used on civil jets because they give part of the benefit of a longer wingspan and therefore higher aspect-ratio. Think "High-aspect" like a high performance sailplane. Longer wings mean less energy loss to wingtip vortices.
However, long wings mean a longer lever trying to break the wing off at the wingroot. That means you have to build your wing stronger--and therefore, heavier.
Winglets give some of the increase in apparent "span," but with less bending-moment.
Fighters:
Since the wings of fighters are generally built for strength anyway (most modern fighters allow up to 9 g, which means they are built to a 13-g ultimate strength), the small gain in efficiency in level-flight is offset by the increase in weight. Weight is a performance-killer in a dog-fight.
Plus, the drag of external weapons, whether they are missiles, bombs, or self-defense jammers, is a far greater variable than the meager savings by using winglets.
Winglets would also make a bigger radar signature, which means easier detection by the enemy.
Last edited by UAL T38 Phlyer; 04-05-2008 at 02:50 PM.
04-05-2008, 04:07 PM
#5
Gets Weekends Off
Joined APC: May 2007
Position: A320 CA
Posts: 1,531
Yup, CCX beat me to the punch, 9' winglets on the C-17.
Fuel is definitely a problem in the military. I have seen a 180 in regards to fuel planning for a typical mission. They are much more concerned (as they should be) at saving fuel. Before prices went high, you could pretty much get away with anything, with only the weakest of excuses. Lately they have been holding our feet to the fire more and more on landing with excess gas.
Fuel is definitely a problem in the military. I have seen a 180 in regards to fuel planning for a typical mission. They are much more concerned (as they should be) at saving fuel. Before prices went high, you could pretty much get away with anything, with only the weakest of excuses. Lately they have been holding our feet to the fire more and more on landing with excess gas.
04-08-2008, 01:08 PM
#8
Gets Weekends Off
Joined APC: Feb 2008
Position: retired
Posts: 645
from the flight deck of the 1900, everything looks big..
In heavy summer rainstorms, I tuck the beech under the tails of the big tin ahead on the taxiways so that I can open the storm window without getting drenched.
Just kidding...
In heavy summer rainstorms, I tuck the beech under the tails of the big tin ahead on the taxiways so that I can open the storm window without getting drenched.
Just kidding...
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