tdscanuck From Canada, joined Jan 2006, 12710 posts, RR: 80
Reply 2, posted (5 years 8 months 1 week 11 hours ago) and read 3121 times:
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.