Like, why not carry them slung under the wings like bombs? Fire bomb tanks have similar shapes and those were slung under the wings.
And from what I’ve seen of public modern fighter jets, they carry their drop tanks under their wings like a bomb.
In: Engineering
Some of them turned out to fly better with wingtip tanks in place, the tanks acted sort of similar to the winglets you see on modern airliners to reduce wingtip vortices. So if you’re going to put a big tank somewhere, might as well put it where it is aerodynamically beneficial. Some modern fighter jets mount missiles there for the same reason.
Also, this might seem counterintuitive, but mounting a heavy weight at the wingtips could reduce the stress on wingspars. The wings lift the whole weight of the fuselage, so if you add heavy tanks closer to the centerline that puts additional bending moment on the wings. Putting the heavy tanks near or at the wingtips helps distribute the load and reduce wing bending moment.
The thin wings and slim bodies of early jet fighters meant that they couldn’t carry a lot of fuel inside their wings or fuselage. So they had wing tip fuel tanks which also helped with reducing drag from wingtip vortices.
They stopped with it because as jets got faster and more maneuverable it put an unacceptable strain on the wings. Instead wings got thicker and shorter (with more room for fuel) and the internal fuel-tank structure got a lot more complicated. Not super complicated in early successors like the F4 phantom (which has very big fuel tank stretching all along the aircrafts belly), but F-14/F-15/F-16/F-18 have a whole bunch of internal fuel tanks trying to utilize every space inside the aircraft hull (the F-16 has 7 different fuel tanks for example. 2 in the wings and then 5 inside the fuselage).
Was looking into a good way to answer this, and came up with an older post in the Aviation sub… not quite ELI5 level, but there’s some good info in here:
What's the deal with wingtip tanks?
byu/SteveDaPirate inaviation
A common problem with fast fighters with thin wings is wing flutter. As the warplane streaks across the sky, small vibrations from numerous sources; engine, turbulence, pilot corrections, starts to add up and makes the wing vibrate and lose lift as the air movement gets disrupted. Putting a weight on the tips or near it dampens the vibrations and makes a smoother flight.
Latest Answers