Originally posted by bipeflyer:
...I have already got some advice re. balance in flight,another guy who flys i.c. ducted fans has a DCU F-14,he advises,as you do,to 'give a couple of clicks'of up trim in minimum sweep conditions.
I finally found the info I was looking for on variable geometry wing designs.
It's at: http://www.hq.nasa.gov/office/pao/Hi...468/ch10-4.htm
Basically, the full-size aviation community went through this exercise with the Bell X-5. They found that when the wing pivot points are on or near the aircraft centerline, then an expected CG shift occurs. The solution for the X-5 was to incorporate a translation mechanism that "slid" both wings forward as they swept rearward.
Research done at the NASA Langley Research Center showed that the CG shift could be minimized by moving the pivot point outboard, away from the centerline and incorporating a highly swept "cuff" that supports the wing and fairs it to the fuselage.
These design features were used on the F-111, F-14, B-1, RAF Tornado and MiG 23/27.
This basically agrees with what your friend who flys the DCU F-14 said about trim changes.