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TS-IOR
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Performance : Freighters Vs. Pax Airliners :

Fri Feb 05, 2010 3:34 pm

Regarding aerodynamic profile... does freighters have a slightly better performance than a passengers airliner of same type ?!

I mean does the lack of windows create a significant ( 1%) improve in performances ?!

For instance, a MD-11F vs MD-11 pax, both with new engines, same load, same fuel quantity, same runway length, same weather, same cost index...
 
Rj111
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RE: Performance : Freighters Vs. Pax Airliners :

Fri Feb 05, 2010 4:35 pm

Weight reduction is probably the biggest factor, and even then the difference is probably marginal.
 
tdscanuck
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RE: Performance : Freighters Vs. Pax Airliners :

Fri Feb 05, 2010 4:46 pm

Quoting ts-ior (Thread starter):
Regarding aerodynamic profile... does freighters have a slightly better performance than a passengers airliner of same type ?!

I suspect the lack of windows has a very very small aerodynamic effect...the boundary layer is going to be substantially thicker than any variation due to the window joints over most of the fuselage. However, as previously noted, the weight savings from the lack of window belt can be considerable.

Quoting ts-ior (Thread starter):
For instance, a MD-11F vs MD-11 pax, both with new engines, same load, same fuel quantity, same runway length, same weather, same cost index..

It's better to specify same gross weight than same load...it's very unlikely that the -11 and -11F have the same OEW, so same load would imply different gross weight, and all your performance factors come from gross weight.

Tom.
 
lowrider
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RE: Performance : Freighters Vs. Pax Airliners :

Fri Feb 05, 2010 7:26 pm

Quoting RJ111 (Reply 1):
Weight reduction is probably the biggest factor,

Freighters aren't always lighter. In some cases a stronger floor must be installed, along with the main deck door, and a cargo handling system. None of these things are light.
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Rj111
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RE: Performance : Freighters Vs. Pax Airliners :

Fri Feb 05, 2010 9:48 pm

Quoting Lowrider (Reply 3):

Quoting RJ111 (Reply 1):
Weight reduction is probably the biggest factor,

Freighters aren't always lighter. In some cases a stronger floor must be installed, along with the main deck door, and a cargo handling system. None of these things are light.

True but this thread is specific to the lack of or presence of windows. And windows always add weight.

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