Wing stores positions

[JeremyH5]

Why are stores and fuel tanks on some aircraft wing tips angled downward relative to the line of the fuselage?

Examples are F16 and Nimrod.

[Eric Mc]

Probably to do with ensuring clean separation when they are released. The airflow pattern around different types of aircraft varies and the behaviour of stores when they are dropped has to be carefully planned and tested. It can go wrong sometimes -

https://www.youtube.com/watch?v=0NVNPn8ilKM

[Mave]

At a guess, to avoid aeroelasticity problems? With a large, high inertia object on the wing tip, you don't want it twisting the whole wing around.

Have a look at this...
http://m.youtube.com/watch?v=Xqbkdy3tBdA

Edited by Mave on Sunday 13th September 12:46

[JeremyH5]

Thanks for the quick replies chaps.

I'll have a look at those videos later; we're at Coventry for the XH558 club celebration so lots to see!

The Nimrod interior tour is well worth the trip.

Edited by JeremyH5 on Sunday 13th September 13:33

[dr_gn]

If it's just the wing tip stores you're looking at, it's probably because the wing tips are twisted down slightly to prevent tip stall ("washout") . It causes the middle part of the wing to stall before the tip, giving better handling at low speeds.

[Ginetta G15 Girl]

On Nimrod the fitting of the YELLOWGATE (Loral pod) at the wingtip caused problems as alluded to above; both with wingtip twisting moment as well as handling at the stall (tip stall).

If you look carefully at the upper wing surface in the region between the 4A tank (the fuel tank that projects forward of the wing) and the pod. you will notice a raft of vortex generators (they look like tiny vertical winglets). These were fitted to re-energise the Boundary Layer airflow and are indicative of the pod's effect on the airflow near the wingtip.

Nimrod MR2 pre YELLOWGATE, Nimrod MR1, and indeed Comet, lacked these vortex generators.

Having said all that, YELLOWGATE is an ESM system (Electronic Support Measures), ie it 'listens' to enemy radars. The configuration of the pod is also critical to the alignment of the antennae within and is optimised for the pitch attitude of the aircraft in the cruise.

Edited by Ginetta G15 Girl on Sunday 13th September 21:16