I hate to destroy Fantasy Island here but this says in abstract considreations for storing fuel in an aircraft:
1 Introduction
A fighter aircraft fuel system is a system of many
parts. Fuel fills up large parts of the aircraft not occupied
with other equipment and the many different
systems of the aircraft often pass through the tanks.
To keep control of the center of gravity the tanks are
divided into smaller parts and are interconnected by
pipes. Fuel is pumped between the tanks to a collector
tank which has a negative g-load compartment to
enable the aircraft to fly inverted. The tanks are also
pressurized to avoid evaporation of the fuel at high
altitudes.
When designing aircraft fuel systems several issues
demand detailed simulation models for analysis.
The most important are
x Is it possible to provide the engine with fuel
with enough pressure regardless of what pilot
maneuvers and equipment faults that occur?
x Can the amount of accessible fuel be correctly
determined at all times?
x Can the structural strength of the hull and all
installation parts be estimated with good
precision?
When these problems are solved, questions related
to optimization of weight, fuel consumption,
and heat storing capabilities as well as other issues
need to be considered.
The fuel system simulation models needed to describe
the system tend to be large (~400 state variables,
~16000 time-varying variables) due to the
high number of parts involved. The combination of
fuel (incompressible fluid) and pressurization air
(compressible fluid) and the necessity to handle both
fast time constants (as when a tank get full) and slow
time constants (heat storage) make the models stiff
and a bit awkward to work with. Still, the information
gained from using the simulation models more
than pays off the work spent to keep the models executable
and is seen as a prerequisite for successful
fuel system design work at Saab Aeronautics. A
theoretical background on fuel system design can be
found in [1] and how Dymola and other simulation
tools are used in the system design process is described
in [2] and [3].
His “pinching” comment amplifies how clueless on aircraft construction he actually is, oh wait, it is here, ZEE PLANE–ZEE–PLANE!
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