Wing tip tanks

[wuzak]

Would wing tip tanks be a useful addition to fighter aircraft to extend their range?

Or would they impose the same performance limitations as drop tanks, without the benfit of being dropable?

 

[davebender]

In a perfect world (which doesn't exist) all fuel would be in fuselage located over center of gravity. That way fuel weight won't adversely effect roll.

Putting additional weight on wing tips would probably be worse for performance then centerline mounted drop tanks. Not to mention considerable strengthening of wings to support weight so far from wing root, which would also be bad for performance.

 

[FLYBOYJ]

Hang anything off the structure of an aircraft and it will degrade performance. Aircraft that were designed to carry tip tanks had some G loading limitations (T-33 comes to mind for me) but in some cases the tanks provide directional stability, this was true for the F-86.

 

[michaelmaltby]

On some AC, do tip tanks not help stabilize the wing tip and smooth vortices ....?

 

[gumbyk]

To a certain degree, but as Flyboyj said, g-loading limitations are a major.
Also, I think you would find that it would degrade roll-rate, with having greater mass further away from the roll axis.

 

[wuzak]

Weight in the wings helps counterbalance the bending in the wing due to lift.

I can see that wing tip tanks will restrict roll rate, particularly when they have fuel in them.

 

[Jenisch]

Not in WWII AFAIK, but there were fighters that had them.

 

[CobberKane]

The Grumman F9F Panther , the USN's first jet fighter, was equipped with wingtip tanks. counter intuitively, these were found to improve roll rate. No idea why.

 

[tomo pauk]

In ww2 fighters, the wing racks were found to reduce speed at very measurable rate, eg. P-51A was loosing 12 mph of max speed with 2 (fairly small) racks installed. The wing racks for the P-47 were also not very liked by pilots, their even bigger size contributing to drag even more.
The wingtip tanks can be installed with negligible drag added, but I guess that really big tanks would still be needed to be hung closer to the CoG, for structural reasons.

 

[GrauGeist]

The U.S. Navy's F2 Banshee also had tip tanks...

I always wondered if a "blister" tank on the fuselage sides would have been better than an outright tank slung under the fuselage, though I don't know if it was ever tried.

 

[GregP]

The F-15 has conformal tanks along the side of the fuselage that apparently result in less of a performance drop than regular tanks. I believe a version was also developed for the F-16. I might be wrong, but I thought the F-16's we sold to Poland had them.

 

[davebender]

It's my understanding Me-110D had one big conformal tank under fuselage. Wartime Germany didn't have time to work technical glitches out so it wasn't popular. Sometimes it didn't release properly which could be fatal for the aircraft.

 

[Milosh]

Spitfires had 3 sizes of tanks that could be attached to the underside of the fuselage.

 

[fastmongrel]

D.H. Venoms used wingtip tanks

 

[davebender]

IMO that looks like a decent job blending fuel tank into bottom of fuselage and it's positioned not to upset aircraft balance. Something similiar might have worked for long range escorts such as P-51D or perhaps a long range Spitfire.

 

[gumbyk]

View attachment 231817
IMO that looks like a decent job blending fuel tank into bottom of fuselage and it's positioned not to upset aircraft balance. Something similiar might have worked for long range escorts such as P-51D or perhaps a long range Spitfire.

Not likely with the P-51 - you'd disrupt the airflow into the radiator intake

They had something similar (Slipper tank) for the Spitfire, although it wasn't as conformal:

 

[drgondog]

Weight in the wings helps counterbalance the bending in the wing due to lift.

I can see that wing tip tanks will restrict roll rate, particularly when they have fuel in them.

True - but one of the first things a stress analyst will look at is a high G landing with full fuel.. lift at minimum, max down load.

 

[wuzak]

Would wing tip tanks on a Lancaster enabled them to upgrade to Griffons and maintain the range of the Merlin Lancaster?

 

[wuzak]

True - but one of the first things a stress analyst will look at is a high G landing with full fuel.. lift at minimum, max down load.

Understood.

I guess then it is a case of whether the AF is prepared to have aircraft damaged in such scenarios, and some sort of risk analysis done.

 

[davebender]

That looks pretty good. Could it be dropped?