ORIGINAL: Montague
Heh, actually in flight, you don't need to have the clunk move to the front of the tank. And in practice it doesn't.
When you dive, there's enough G-force to hold the fuel at the back of the tank, so your plane runs out of air before your engine runs out of fuel. Holding the plane still and nose-low isn't something that happens in flight unless you really work at it.
Eh... this is a misconception.
We covered this ad-nauseum in the other thread.
The plane does not accelerate in a nose down attitude fast enough to hold the fuel at the back of the tank.
To keep the fuel back there it would need to maintain an ACCELERATION rate equal (rather greater than) to 1G/(percentage inclination to the horizon)*some factor.
e.g. the further the nose is down, the higher it must maintain a constant acceleration rate.
Of course that can't happen so that means, even in a slight nose down attitude the clunk can become uncovered esp. when say coming in for a landing on a long glide.
This is not too problematic until the plane starts running down on fuel.... that is at less than half a tank the problem starts to surface, but at about 1/4 tank it really kicks in as all it takes is a -15 degree or so attitude to uncover the clunk. The uncovered clunk makes the plane behave as if it were out of fuel prematurely.
Of course one could argue that why fly this amount of fuel... but then I like to maximize my flight times.