Wingtip shape (rounded, squared)

[gjs238]

What are the advantages and disadvantages of the different wingtip shapes?
Why did some designs choose one over the other?

Thanks

 

[drgondog]

What are the advantages and disadvantages of the different wingtip shapes?
Why did some designs choose one over the other?

Thanks

There existed a perception that aerodynamically a rounded wingtip lessened the intensity of the vortex at the wingtip. Although this concept is true, it is negligible in in subsonic flow.

At the end of the day, the taper ratio is more important - primarily for low speed roll control/delay tip stalls.

 

[Grampa]

Is that the reason why Messerschmitt chosed to build the Me 109 F and later version whit rounded wingtip instead of the old square version?

 

[davebender]

The Me-109F and Me-109G were about 50mph faster. Perhaps that is a factor.

 

[drgondog]

It is hard to say how much contribution to Reducing tip vortex, and thereby mitigating induced drag, the rounded wing tip contributed. Horner for example estimates that the rounded tip effectively decreased aspect ratio by 2% but I can't (yet) see a discussion on corresponding effect of a 'square' tip.

Willy must have seen a benefit because the rounded tip should be a little more expensive. Having said this you have to think that the empirical results were not conclusive as neither the Mustang of the HellCat, etc had rounded wingtips in any version.

The increase in speed from E to F/G was a lot more about Hp than the extremely small possible contribution to reduced induced drag by the wing tip geometry. At max speed the Drag is overwhelmingly due to Parasite Drag than Drag due to lift - as the AoA and corresponding CL is at a minimum at max speed.

 

[davparlr]

I suspect that any advantages of rounded wing tips disappears with increased airspeed which would imply it is part of induced drag. It appears that very few, if any, unlimited racers have rounded wing tips where every mph is a valuable asset. Like spinners, huge increases in hp makes any advantages negligible.

 

[swampyankee]

I suspect that the two major reasons for rounded wingtip are aesthetics and ease of manufacture, especially when fabric covered. There are tip treatments known at the time that reduce induced drag, such as endplates or tip tanks; later Whitcomb's winglets (inspired by F.W. Lancaster's work in the late 19th Century)

 

[Graeme]

The ultimate "square" wingtip...