Straight wing better in gusty conditions

[buzzc152]

Simple question ; are straight wings better at coping with gusty conditions than a swept wing ? If so, why ?

[PDR1]

Straight wings can have less/no inherent yaw-roll coupling.

PDR

[Mad (Flt) Scientist]

A straight wing will in general have a higher CL-alpha slope than a swept wing of otherwise equivalent performance. Thus the gust response of a straight wing will be greater than the equivalent swept wing.

That was one reason for the swept wing (or sweeping wing, for the relevant aircraft0 for a low level penetration role. You get better ride quality from the swept wing.

But it depends what you are considering as the "mission" - if it's landing and low speed stuff rather than high speed low level stuff, then straight may well win out.

[westhawk]

"Better" is a rather broad term to describe handling characteristics! And open to some subjective interpretation perhaps?

However if the question is related to what type of wing design would provide the smoother ride in turbulence, then wing loading would probably be a more directly relevant consideration than sweep angle alone. So too would the cross-sectional shape of the airfoil have a greater influence upon how much increase or decrease in lift resulted from a given change in AOA.

In addition, several other factors such as wing camber and it's effect upon CP location, and stabilizer and flight control surface area/distance from the CG can affect pitch stability in the bumpy stuff. This will have an effect upon the perceived quality of the ride.

In other words, there are a whole host of design factors which can affect how "good" an airplane rides out atmospheric turbulence, wing sweep angle being just one of them. The big advantages of wing sweep being related to less mach induced drag at higher sub-sonic/trans-sonic cruise speeds, some compromises to handling characteristics may be deemed necessary by the designers in order to achieve the desired performance.

It seems that allot of effort has been directed towards solving swept wing related handling difficulties! But then that's a pretty good definition of what what airplane designs really are: A series of performance, economic and operational design compromises made in order to produce an airplane which can be built at an optimal profit. The quest to achieve the "perfect" airplane design continues...

Swept, straight, highly loaded wing or otherwise, Just build me an airplane suitable for it's intended purpose and I'll be happy to fly it!

[Capn Bloggs]

Give me a swept-wing jet at max landing weight minus a bit any day. Straight wings are for Cessnas and boats...

[misd-agin]

Higher wing loading is your friend, until you screw it up and it gets away from you.

[FE Hoppy]

For the same wing loading a swept wing will give a smoother ride.

[mustangsally]

I'm confused. Straight wings are not sweep wings. A metro liner or C-130 has a straight wing. All Falcon's, Lear's, Cessna's have sweep wings. Boeing's and Airbus's have sweep wings. Or, are we looking at stiff wings compared to flexing wings? Just a quick think, B-52's had a high flex wing, B-727, 737, A-320 have little or no vertical flex. the B787 is reported to have more flex to promote soother cruise comfort. I'm missing your point.

[Intruder]

I suspect there is more to it than a simple sweep vs straight, or stiff vs flexible, decision. Dynamics, damping, and resonant frequencies likely all come into play.

The best-riding airplane I've flown in turbulence was the Douglas A-4 Skyhawk: stiff, swept delta wing, high wing loading.

[aterpster]

Mad:

But it depends what you are considering as the "mission" - if it's landing and low speed stuff rather than high speed low level stuff, then straight may well win out.

Thus, the smart guys included yaw dampers. At first not so smart with part-time yaw dampers, but soon with full-time yaw dampers. (Parallel vs. series?)

[RVF750]

Wing loading is the key in turbulence. I used to much prefer my landing little Cessna's flapless in gusty conditions for that reason.

I suspect a good part of this relate to cross wind where a straight wing does win out due to a far reduced roll moment with yaw. Thus you can get better cross wind limits. Not nice to hit the stops on the wheel in a 737 with winglets but it happens regularly....

[gus_eng]

@Mad (Flt) Scientist

Hi, I'm new in the forum so I can't PM you. May I directly contact you? I have a question regarding an old post of you.

Thanks!

[Mad (Flt) Scientist]

sure, go ahead