Originally Posted by
Wizofoz
Agree with you up to this point- any positive G should not result in fuel feed problems, and Airliners sre stressed to (IIRC) +2.2 -1 G with flaps up.
Re Fuel feed:
Yes between 0 and 1g there is still a good chance of continuous fuel feed but the reliability will be reducing with the g load. Reason being that the inertial mass of the liquid remains the same while at the same time the force pulling the fuel down (into the outlet) reduces. Therefore disturbances will cause increasing levels of swirling in the tanks. Therefore with low fuel levels in the tanks keeping the sustained g > +0,5 in a non-aerobatic aircraft might not be a bad idea even though levels below should not immediately lead to disaster. It's just not extremely prudent.
The allowed stress level of an airframe will indeed only be the limiting factor for the altitude you need for the recovery.