Why the small wing?

Always wondered why the F-16 has a tailhook, or how big a bigmouth F-16's mouth really is ? Find it out here !
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johnwill

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Unread post01 Apr 2019, 17:50

madrat wrote:Johnwill-

The LERX on F-16 has always intrigued me. I notice the F-16 has a very narrow LERX similar to the Hornet. Was a wider LERX, like on a Super Hornet, counter productive? The F-35 seems to use a decoupled LERX with the chine from the upper intake forming sort of a bi-plane effect not really dissimilar than how Rafale shapes the canard shoulder over the leading edge of the main wing. I have to imagine again, the net effect just wasn't a benefit or we would have seen something similar backfir to the F-16. Was the LERX in the F-16 changed much from the concept to the final product, e.g. to get to its current shape?


LERX on a twin vertical tail airplane can be a can of worms due to interaction of the vortices with the tails. The Hornet found that out the hard way, so ever since then, designers have been very careful to avoid that problem while still meeting the RCS, lift, and drag needs. As always, the final design is a compromise between several competing requirements.

Several different shapes were studied during design of YF-16, but once the shape was selected it wasn't changed, even to the current airplanes.
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n3sk

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Unread post02 Apr 2019, 23:29

So it seems the wing design of the F-16 is the best compromise. Any change causes issues that are not worth the effort or negatively affect another aspect of performance.

The CTF’s do cause minor yaw control issues and high speed. They do not and much meaningful lift.

Power is the answer to make up for the added weight.

One place I commonly see vapor vortices is the lerx and wings leading edge meet. If there is enough pressure to squeeze moisture out of the air, is this also a sign of turbulence and drag??

This question is a bit off topic but relates. These vortices mentioned which cause problems for twin tail jet, is that why the Su-57 has levcons. Is it an attempt to alleviate this issue and smooth out the airflow over the top of the fuselage. Will we see these in future design?
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madrat

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Unread post03 Apr 2019, 02:23

Levcons seem to act like Handley-Page slats. keeping the front edge inline with airflow then smooths laminar airflow over the wing I reckon. Just from an eyeball guess, it probably helps smooth airflow at high AoA.

Instead of levcons, I think any future changes on a design should be to cut drag. I wonder how a Y-tail like on F-117A would function on an F-16 by eliminating both the vertical stabilizer and horizontal tail planes. Maybe the ventral side of the tail section could be slat free with some sort of aerodynamic package that more closely conforms to the body. Stuff like that. The downside is it's money thrown into the wind since we already have F-35A.
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saberrider

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Unread post03 Apr 2019, 05:20

n3sk wrote:So it seems the wing design of the F-16 is the best compromise. Any change causes issues that are not worth the effort or negatively affect another aspect of performance.

The CTF’s do cause minor yaw control issues and high speed. They do not and much meaningful lift.

Power is the answer to make up for the added weight.

One place I commonly see vapor vortices is the lerx and wings leading edge meet. If there is enough pressure to squeeze moisture out of the air, is this also a sign of turbulence and drag??

This question is a bit off topic but relates. These vortices mentioned which cause problems for twin tail jet, is that why the Su-57 has levcons. Is it an attempt to alleviate this issue and smooth out the airflow over the top of the fuselage. Will we see these in future design?

The vortices is a s presense from the medium AOA in flight on F16 LEX's. Sweept angle (more 60 degree's) create them at lowAOA. They're being useful at high pitch angles when WINGS start to loose lift to drag ( increase)
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saberrider

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Unread post21 Apr 2019, 09:53

The wings are small (wingspan wise) to accomplish minimum drag request for the payloads .
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vilters

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Unread post21 Apr 2019, 20:49

The production F-16's wing is 10% bigger then the YF-16 wing, and many of us want to torture the clowns that shelved the XL-F-16 WIng.
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