Forum: Technology

...other than relaxed stability. Every since fly-by-wire and relaxed stability, no new variable-sweep wings have been incorporated into aircraft design. Sure, it adds weight and complexity, but, with the now widespread use of composites and emphasis on both long endurance and high penetration speeds, could variable sweep make a come-back, for example in a supersonic/supercruising but long-loitering UCAV? I'd be interested in your thoughts.

Btw, I'm aware of the switchblade, but that design seems to be more trouble than it's worth, especially for a larger scale design.

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Elite 1K Joined: Aug 19, 2004 - 09:19 AM Posts: 1092

Besides weight and complexity, variable geometry wings are difficult (if not impossible) to make stealthy. In addition, you don't have many (if any) wing pylon stations available for a swing wing design. You get a much more well-rounded aircraft without swing wings than with.

Salute!

Rap has it nailed.

Swing-wings, big planes.

RCS is a bitch when you look at the wing roots.

later,

The last new variable sweep fighter that was produced was the Tomcat. Every U.S. fighter produced since then has a smaller turning radius, is lighter, easier to maintain, and has a lower RCS...even the Eagle.

The B-1 has an RCS something like 1/4 the size of the BUFF, but is by no means stealthy. Later, the B-2, of course, went to a fixed-flying wing design.

Variable sweep is archaic technology.

Another thing is that Mach 2.5 has fallen out of favor as a prime requirement. Fixed wings are more than capable of supporting performances up to Mach 1.8~2 without compromising low speed handling and cruise efficiency. The BIGGEST reason for swing wings is to support flight in the Mach 2~2.5 bracket.

The problem is that that is not something we care about too much. We'll rather focus on being able to cruise at Mach 1.7 than being able to make a short dash at 2.5.

I'm kind of wondering if VG wings could gain more effectiveness if they had an increased ability to modify the aerodynamic characteristics of a fighter plane?

What if it could be used for forward sweep in addition to unswept and rearward swept configurations? Various advantages (and disadvantages) have been shown for FSW, so adding them to a jet's repertoire of planforms could potentially enhance its combat effectiveness when the situation calls for it (such as high agility and high AoA performance).

Would I be correct in assuming that the Tomcat and other such VG aircraft utilized a mechanical method for moving the wings? Might a system that uses electromagnetic components to move the wings be more efficient and less likely to break down? You know, like how some levitating trains and roller coasters use magnets to move. Using electromagnets powered by the aircraft's engines might offer a safer system as there are no moving parts (other than the wings themselves, obviously).

Feel free to shoot my ideas down, though.

Kryptid wrote:

I'm kind of wondering if VG wings could gain more effectiveness if they had an increased ability to modify the aerodynamic characteristics of a fighter plane?

What if it could be used for forward sweep in addition to unswept and rearward swept configurations? Various advantages (and disadvantages) have been shown for FSW, so adding them to a jet's repertoire of planforms could potentially enhance its combat effectiveness when the situation calls for it (such as high agility and high AoA performance).

Would I be correct in assuming that the Tomcat and other such VG aircraft utilized a mechanical method for moving the wings? Might a system that uses electromagnetic components to move the wings be more efficient and less likely to break down? You know, like how some levitating trains and roller coasters use magnets to move. Using electromagnets powered by the aircraft's engines might offer a safer system as there are no moving parts (other than the wings themselves, obviously).

Feel free to shoot my ideas down, though.

I think the electromagnetic components would probably be very heavy, not to mention power intensive. I think a wing like that also has problems with changing the CG and center of lift pretty dramatically, which probably wouldn't be able to be dealt with without further additions of weight and degradation of performance.

I remember you from DA, by the way!

Quote:

I think the electromagnetic components would probably be very heavy, not to mention power intensive. I think a wing like that also has problems with changing the CG and center of lift pretty dramatically, which probably wouldn't be able to be dealt with without further additions of weight and degradation of performance.

I figured that the center of lift would be a problem. I had the idea of using a variable-dihedral V-tail to help keep the center of lift under control, but that would add to weight and complexity.

Quote:

I remember you from DA, by the way!

You have an account there?

Kryptid wrote:

Quote:

I think the electromagnetic components would probably be very heavy, not to mention power intensive. I think a wing like that also has problems with changing the CG and center of lift pretty dramatically, which probably wouldn't be able to be dealt with without further additions of weight and degradation of performance.

I figured that the center of lift would be a problem. I had the idea of using a variable-dihedral V-tail to help keep the center of lift under control, but that would add to weight and complexity.

Quote:

I remember you from DA, by the way!

You have an account there?

Sure do.
http://prinzeugn.deviantart.com/

Hmm, now that I think about it, it'd be pretty hard to get all the connections (electrical, etc.) to work correctly on that through the whole range of motion. And pylons. Although, really, that would be a trip to get that working... an aerodynamicist's wet dream.[/url]

dwightlooi wrote:

Another thing is that Mach 2.5 has fallen out of favor as a prime requirement. Fixed wings are more than capable of supporting performances up to Mach 1.8~2 without compromising low speed handling and cruise efficiency. The BIGGEST reason for swing wings is to support flight in the Mach 2~2.5 bracket.

*cough* bull$hit.

How many Mach 2.5 capable aircraft have had swing wings? Exactly ONE- the F-111F.

There you go sferrin! The F-111F: The TRUE "Switchblade". Light the blow torches baby! Cool

The Statue of Liberty Wing: Libyan Urban Renewal

TC wrote:

There you go sferrin! The F-111F: The TRUE "Switchblade". Light the blow torches baby! Cool

The Statue of Liberty Wing: Libyan Urban Renewal

I have an F-111 book around here somewhere that talked about further developements of the TF-30. They had plans for taking it all the way to 30,000lbs+ Shocked

That woulda been something in either the F-111 or the Tomcat. Also there was a guy over on rec.aviation.military who said they briefly had an F up to Mach 2.8.

Not sure on the exact Max speed of the 'Vark, but to give you a little taste, so to speak, I quote Gums:

Gums wrote:

The 'vark was the premier low-level jet for a few decades. If you had a bad setup, no way could you run it down. And it had lots longer legs than the Thud, which could also "go in at 600 knots, then come out FAST!"

If the 'Vark was hauling @$$, down in the weeds, Fuhgeddaboudit. No way to catch that sucker. An Iraqi Mirage Driver found this out the hard way against an EF flying TFR in ODS...to date the F-111 fleet's only AA kill, and all they had to do was fly straight, low, and fast. Laughing

The fastest-moving thing I've ever seen up close was a Thud. The second-fastest moving thing I've ever seen up close is a 'vark. That's my story and I'm sticking to it!

Last edited by LinkF16SimDude on Nov 21, 2008 - 07:11 PM; edited 1 time in total

May be slightly Off Topic

but Vark related.

When I moved to Klamath Falls, OR back in '89, I took US95/NV140 north outta Winnemucca, NV (whatdahell's a "Winnemucca"?!) up towards Denio Junction...just cuz it looked like a nice drive. Out in the middle of the desert floor I spot this, well, spot, comin' right at me really REALLY low and really...REALLY fast. At about 3/4 mile the spot turned into a Vark with the wings fully swept.

At the merge he was (my guess) maybe 150 ft. off the deck and easily doin' 500+ indicated. There was nobody and nothing out there besides me and my overstuffed Caprice Classic to keep him from flyin' that low if he wanted. Rattled the car a bit but I maintained my cool. 570+ knots o' closure will do that to a Caprice. Wink

My guess was they spotted me on the ground map radar or whatever gadget they used miles before I even noticed 'em and they decided to have a chuckle. Twisted Evil

Looked in the rear view and they were nice enough to gimme a couple of wing rocks before disappearin'. Cool

Forum: Technology

Whatever happened to variable sweep...