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#1
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Why a Swept-Wing?
Pardon my ignorance on all matters concerning modern aviation but just
why the hell would you want to sweep a wing forward? Doesn't that make any aircraft unstable? If so, why would any pilot feel safe in it? Has anyone ever made one work? James Dandy |
#2
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"James Dandy" wrote in message
m... Doesn't that make any aircraft unstable? If so, why would any pilot feel safe in it? I imagine it would move the centre of lift forward of the centre of gravity, which might help to increase lift at slow speed or high angle of attack. (I think..) Si |
#3
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This is taken from Aerospace web
http://www.aerospaceweb.org/aircraft/fighter/s37/ "The advantages of forward sweep have long been known as such wings offer lower wave drag, reduced bending moments, and delayed stall when compared to more traditional wing shapes. Unfortunately, forward sweep also induces twisting strong enough to rip the wings off an aircraft built of conventional materials. To solve this problem, the Su-47 makes use of composite materials carefully tailored to resist twisting while still allowing the wing to bend for improved aerodynamic behavior. " "However, Sukhoi has apparently decided to abandon the forward-swept wings of the S-37, and the future production model will return to a more conventional wing layout. If true, Sukhoi may have reached the same conclusion as NASA did following testing of the X-29--the benefits of forward-swept wings are just not worth the extra cost and complexity associated with their design and manufacture." Curt "James Dandy" wrote in message m... Pardon my ignorance on all matters concerning modern aviation but just why the hell would you want to sweep a wing forward? Doesn't that make any aircraft unstable? If so, why would any pilot feel safe in it? Has anyone ever made one work? James Dandy |
#4
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"C Knowles" wrote in message m... This is taken from Aerospace web http://www.aerospaceweb.org/aircraft/fighter/s37/ "The advantages of forward sweep have long been known as such wings offer lower wave drag, reduced bending moments, and delayed stall when compared to more traditional wing shapes. Unfortunately, forward sweep also induces twisting strong enough to rip the wings off an aircraft built of conventional materials. To solve this problem, the Su-47 makes use of composite materials carefully tailored to resist twisting while still allowing the wing to bend for improved aerodynamic behavior. " "However, Sukhoi has apparently decided to abandon the forward-swept wings of the S-37, and the future production model will return to a more conventional wing layout. If true, Sukhoi may have reached the same conclusion as NASA did following testing of the X-29--the benefits of forward-swept wings are just not worth the extra cost and complexity associated with their design and manufacture." Actually, once the notch filter was adjusted such that the wing did not delaminate, there was no benifit to forward swept wings. The program falsified X-29 flight test data and USAF was quite punative in blackballing the whole group. Perhaps Mary would like to speak to that issue, as she was very close. "James Dandy" wrote in message m... Pardon my ignorance on all matters concerning modern aviation but just why the hell would you want to sweep a wing forward? Doesn't that make any aircraft unstable? If so, why would any pilot feel safe in it? Has anyone ever made one work? James Dandy |
#5
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On Sun, 11 Jan 2004 09:57:12 -0800, "Tarver Engineering"
wrote: Actually, once the notch filter was adjusted such that the wing did not delaminate, there was no benifit to forward swept wings. Uh... excuse me, but what's a "notch filter" in this context? -- __________ ____---____ Marco Antonio Checa Funcke \_________D /-/---_----' Santiago de Surco, Lima, Peru _H__/_/ http://machf.tripod.com '-_____|( remove the "no_me_j." and "sons.of." parts before replying |
#6
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"machf" wrote in message news On Sun, 11 Jan 2004 09:57:12 -0800, "Tarver Engineering" wrote: Actually, once the notch filter was adjusted such that the wing did not delaminate, there was no benifit to forward swept wings. Uh... excuse me, but what's a "notch filter" in this context? In the feedback control system of the X-29 was a z-transform type filter at 3.2 Hz. This was a simple third order filter in the original airframe. Once the filter was altered to eliminate the flutter problem on the second airframe, there was no manuverability advantage. The first airframe having a delaminated wing by that time. |
#7
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On Mon, 12 Jan 2004 08:04:07 -0800, "Tarver Engineering"
wrote: "machf" wrote in message news On Sun, 11 Jan 2004 09:57:12 -0800, "Tarver Engineering" wrote: Actually, once the notch filter was adjusted such that the wing did not delaminate, there was no benifit to forward swept wings. Uh... excuse me, but what's a "notch filter" in this context? In the feedback control system of the X-29 was a z-transform type filter at 3.2 Hz. This was a simple third order filter in the original airframe. Once the filter was altered to eliminate the flutter problem on the second airframe, there was no manuverability advantage. The first airframe having a delaminated wing by that time. Oh, I see... I forgot that the X-29 had to rely heavily on electronics, and thought maybe it was some mechanical equivalent or something. Thanks for clearing that up. Ah, z-transforms... It's been quite a while, but I used to be pretty good at that stuff. -- __________ ____---____ Marco Antonio Checa Funcke \_________D /-/---_----' Santiago de Surco, Lima, Peru _H__/_/ http://machf.tripod.com '-_____|( remove the "no_me_j." and "sons.of." parts before replying |
#8
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#9
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#10
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The Hansa jet had forward sweep- the one pilot that had flown said type
stated no unkind words on the plane. Pat |
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