Airfoil twist

Anything goes, as long as it is about the Lockheed Martin F-22 Raptor
  • Author
  • Message
Offline

Patriot

Senior member

Senior member

  • Posts: 348
  • Joined: 02 Sep 2006, 17:48
  • Location: Poland / UK

Unread post20 Oct 2017, 13:05

I'm not sure whether this thing have been already touched or not but this is the question. I've noticed that Raptor's wing is somehow convoluted somewhere starting from midsection to the wingtip, leading edge is flexed clearly down and trailing edge is flexed up. I guess F-35 has more or less the same feature. I havnt seen it on F-18s, F-16s, not quite sure about F-15.

What tahat actually is and what it's for? I'm guessing it has to be benefitial from an aerodynamic standpoint.. I dont know, less induced drag, supercruise? Im wondering.

It's quite well visible on a frontal plane

Image
Offline

vanshilar

Senior member

Senior member

  • Posts: 365
  • Joined: 26 Aug 2015, 11:23

Unread post20 Oct 2017, 14:12

Though this won't fully address your question (especially as to whether or not this is the reason why the F-22 has it), but this is known as washout.

https://en.wikipedia.org/wiki/Washout_(aviation)
Offline
User avatar

rheonomic

Senior member

Senior member

  • Posts: 383
  • Joined: 30 Apr 2015, 03:44
  • Location: US

Unread post20 Oct 2017, 18:57

Most wings will have different airfoils, etc along the span to allow the aerodynamics guys to tailor the lift distribution, help out with S&C, etc.
u = (CB)⁻¹(cvdt_des - CAx)
Offline
User avatar

count_to_10

Elite 3K

Elite 3K

  • Posts: 3148
  • Joined: 10 Mar 2012, 15:38

Unread post21 Oct 2017, 03:36

My guess would be that the twist has to do with the angle of attack various parts of the wing stall at.
Einstein got it backward: one cannot prevent a war without preparing for it.

Uncertainty: Learn it, love it, live it.
Offline

johnwill

Elite 2K

Elite 2K

  • Posts: 2003
  • Joined: 24 Mar 2007, 21:06
  • Location: Fort Worth, Texas

Unread post21 Oct 2017, 07:06

Another benefit of twist in the wing is reduced structural weight, both in the wing and the fuselage. There are two kinds of wing twist, static and elastic. Static is the twist with zero load on the wing. Elastic is the twist due to load on the wing. For F-16, static is 3 degrees from wing root to tip. Elastic can be as much as 4 degrees, so total twist can be up to 7 degrees.

So how does that save structural weight? As mentioned earlier the tip area has a lower angle of attack and lift due to the twist. That moves the center of lift inboard and reduces wing bending moment and fuselage bulkhead moment for the required total wing lift.
Offline

mixelflick

Elite 1K

Elite 1K

  • Posts: 1641
  • Joined: 20 Mar 2010, 10:26
  • Location: Parts Unknown

Unread post21 Oct 2017, 15:18

This feature is more prominent from the back IMO, and I've often wondered why it's there too.

Gives it an edgier look IMO. From the front or back, she looks real mean...

Return to General F-22A Raptor forum

Who is online

Users browsing this forum: No registered users and 7 guests