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Old 13th June 2008 | 23:37
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actus reus
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vertical CG

I
I believe that the now delayed A380F was to have the upper deck lowered approx 4" with reference to the pax version, to allow the use of large cargo pallets on the upper deck. The need here was to increase the available, combined total floor loading towards 10kg/square m. The flight control's authority to cope satisfactorily with the range of vertical CG was not in question IIRC.
I know you don't want to hear it but I can't help myself. I agree with MFS etc; the lift on the tailplane is negative in most civilian aircraft. If you wish to improve the SFC in the cruise, an aft CG will allow a reduction in trim drag on the tailplane. An aft CG will also help with the RTOW / Vspeed calcs.

If you wish to go even further but still shy away from exotic flight control systems such as the F16, then a reduction in the static margin will do even better (health warning on this though).
Under wing engines, amongst other things, allow the pylons by which they are attached to act as vertilons and the 'jet upset' recovery proceedure adopted by both BAC and AI (Mike C was the Boeing tp; I can't recall the AI tp) does call for the thrust to be reduced in the extreme nose high/low IAS situation
Actus

Last edited by actus reus; 14th June 2008 at 12:36. Reason: typo
 
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