Originally Posted by
astroglider
I'm doing some research on fuel balancing procedures for various aircraft. I have no experience with aircraft equipped with tip-tanks and was wondering what the fuel burn procedure is for them? Say a Learjet. I know you have to add fuel to the tanks in a certain order...but what about when you burn the fuel?
Anyone?
Airplanes with tip tanks vary greatly.
The Lear 25 and 35/36 fuel directly into the tip tanks and use pumps to transfer to the center tank. If you're fueling the "tips only: you can fuel full blast with no kick back. If they need to transfer to the center tank, you have to wait longer to re top the tip tanks. The 36 has a bigger center tank so you may have to wait around longer.
The Westwind I has tip tanks but fuels through fuel inlets on top of the fuselage and flows into the wings and tip tanks. There are also manual valves (little sticks under the wing you pull to manually open) to allow fuel to flow to the tips.
The Westwind II had singlepoint.
MU-2 are just monsters. Tip tanks and inner wing tanks. No fuel imbalance over 50 gallons and getting to the 15 gallon inner tanks was always a PITA due to the limited space between the fuselage and the engine. The even had weird fuel caps.
It was always fun to watch the wing drip as you fueled one side or the other. Especially if you were alone. Also, NEVER place a ladder under the wind or tip tank.
Twin Cessnas were interesting, the tips were the main tanks and the wing tanks were the aux tanks (except the later models with out tip tanks like the 414A and 421C).
The return fuel line from the engine flowed ONLY into the main tank (tips) this means you had to burn from the tips for at LEAST an hour before using aux tanks. If you use the aux first, the return fuel will overflow the main tanks the dump the excess overboard.
Also, some of them had nacelle tanks to add to the complications.
I'm pretty sure that bonanza tip tanks were directly piped to the wing tanks, (not 100% sure on this one)
G-2's also had tip tanks but I'm not sure about the fueling requirements and burn on that one.