Weight, Balance and Polar Moment of Inertia

[photofly]

The most extreme example I can think of offhand, would be concorde.

Anything else *require* retrimming by moving fuel in flight?

[looproll]

Interesting discussion. Thanks for the contribution CS!

[trampbike]

I didn't know about the Concorde trim system. Very interesting!
Did they have a flight engineer dedicated on monitoring that fuel system? Must have been a pretty daunting task.

[Colonel Sanders]

Anything else *require* retrimming by moving fuel in flight?

I'm sure there are lots. B-58 Hustler comes to mind.

http://50.137.56.231/b-58/history_engines.cfm

The fuel system was the most complex and sophisticated yet installed in an operational aircraft due to the tight space restrictions, the problem of fuel "stacking" or movement of fuel in the tanks due to high-G manuevers, and complex center of gravity requirements to keep the airplane properly balanced. The JP-4 fuel was stored in four main tanks, termed forward, aft, reservoir and balance units. Two more fuel tanks were installed in the under-fuselage pod (a total of 4172 US gallons in the MB or LA pod and 3885 US gallons in the TCP pod).

The center of gravity could be maintained either automatically or manually by transferring fuel between the forward, aft and balance tanks.

By the end of 1957, the YB-58 had attained a maximum speed of Mach 2.11 at altitudes over 50,000 feet. It had made two successful pod drops from 42,000 feet at speeds of over Mach 2. Malfunctions in the fuel system caused the fuel to slosh around (fuel stacking) in the fuel tanks when the aircraft accelerated or slowed down, causing stability problems.

When I was a little kid, I had a nice framed painting
of the Hustler on the wall of my bedroom. In retrospect
I had a pretty weird childhood, though of course at the
time I didn't know that. Wonder where that painting
ever ended up.