"Roy Smith" wrote in message
...
In article ,
Ron Natalie wrote:

Jim Macklin wrote:
The 727 has a prop. They install it under the tail while
parked.

Either that or you drop the rear airstairs if the plane is
so equipped. Don't know about the 727, but some of the
DC-9's you HAD to do that. When the plane was empty
it only took a couple of guys standing in the back to
tip it up off the nose gear.

I once read that the Concorde used to pump fuel around after landing to
move the CG far enough forward that departing pax wouldn't tip it over.

They also did a lot of active CG management (by pumping fuel around) in
flight as they went from subsonic to supersonic and back.

I found out during my Private checkride, during the oral portion, that
apparently the 747 has a tank in the tail and that the procedure used to be
basically "burn it when you want", but to avoid getting caught in an aft CG
situation, they pump the fuel from the tail tank to the main tanks as soon
as practical. My DE was a 747 captain for NWA, and he had asked me "Which
is more efficient, an aft CG or a forward CG? Which is more stable?" and we
were discussing things and he used the 747 as an example.