some info of internal/external fuel tank
sequence
The normal fuel transfer procedure from external to internal is
to transfer fuel from the centerline tank first, then from the
external wing tanks. However, this may be overridden by setting the
fuel transfer switch to WING FIRST.... according to the Falcon 4
(SP3) manual.
According to that same manual, the fuel system of the F-16 is based
on the Forward/ Right Left/Aft layout. The fuel is divided into two
systems, the F/R and L/A, and is fed from both systems to the
engine. In this way balance is maintained and the aircraft does not
become too nose or tail heavy or have a tendency to roll.
The fuel storage system is composed of the following:
* Two Reservoir tanks, these hold 480lbs of fuel each and feed the
engine directly. One reservoir is for the F/R and the other L/A
system.
* Forward and aft fuel tanks hold the bulk of the internal fuel.
They feed into the appropriate reservoir tanks.
* The wing tanks which feed the forward and aft tanks, the left
wing tank feeding the aft main tank, and the right feeding the
forward tank. These tanks hold 550lbs of fuel each.
* External tanks feed into the wing main tanks. The wing externals
feed into the appropriate wing tank, and the centerline feed into
both. Capacity is dependent on the tank size loaded.
The fuel is transferred from the reservoirs to the engine. There
are fuel pumps that are normally activated to aid the transfer, but
the main transfer mechanism is gravity and siphoning between tanks.
The fuel then goes through the Fuel Flow Proportioner (FFP). It
adjusts flow rates from the two systems to maintain the balance of
fuel between F/R and L/A systems to maintain the aircraft's center
of gravity. Should the FFP fail (it is part of the 'A' hydraulic
system) then erratic distribution may occur leading to a center of
gravity imbalance.
The fuel then goes through the main fuel valve to the engine (where
it burns!). The amount of fuel in the F/R and L/A is shown on the
fuel gauge. More important is the ratio of the fuel in the tanks.
If the difference is too large, a center of gravity imbalance will
occur. Attention to the fuel gauge indicators is important beyond
just assessing remaining fuel.
by Whity
PostPosted: Feb 03, 2004 - 05:38 PM
