"Advances in aerodynamics have made the swing-wing obsolete"

[Basil]

Can the very thick wing root sections of the swing-wing B-1 and Tu 160, which extend to the swivel bearing, be regarded as supercritical airfoil section? If yes, you have examples of a supersonic application.

 

[Scott Kenny]

Can the very thick wing root sections of the swing-wing B-1 and Tu 160, which extend to the swivel bearing, be regarded as supercritical airfoil section? If yes, you have examples of a supersonic application.

Maybe? I'm not sure they have quite the right shape. A supercritical airfoil isn't just an elliptical leading edge, it's a flat upper surface back a ways.

 

[Colonial-Marine]

I was recently doing some reading on the history of the F-111 and the difficulties with the wing carry-through box structure resulting in the cold proof load testing procedure. It got me to thinking if there is any information available on what issues the Soviets encountered during the service of their VG fighters and bombers?

I'd have to presume this is one of those unforeseen types of structural failures where if GD hadn't encountered it first with the F-111 other designer would have when their VG aircraft entered service.

 

[pathology_doc]

Here are a few pics:

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That thing's wing looks like its mother had a night out with a Handley-Page Victor.

 

[Cannonfodder43]

I was recently doing some reading on the history of the F-111 and the difficulties with the wing carry-through box structure resulting in the cold proof load testing procedure. It got me to thinking if there is any information available on what issues the Soviets encountered during the service of their VG fighters and bombers?

I'd have to presume this is one of those unforeseen types of structural failures where if GD hadn't encountered it first with the F-111 other designer would have when their VG aircraft entered service.

https://twitter.com/x/status/1776649789003682154

View: https://twitter.com/BaA43A3aHY/status/1776649789003682154?s=19

 

[Scott Kenny]

That sounds like a very complicated hinge joint on the Su24...

Anyone got pictures of it?

 

[Kiltonge]

Apparently the F-8 SCW demonstrator was an absolute beast, test pilots had to be told to stop mugging F-14s etc.

It also landed at 200kts, and the 15,000ft Edwards concrete runway was too short for to land there. Maybe VG would have helped...

Supercritical profiles are great for transonic cruise, but aren't a panacea.

 

[Scott Kenny]

It also landed at 200kts, and the 15,000ft Edwards concrete runway was too short for to land there. Maybe VG would have helped...

Supercritical profiles are great for transonic cruise, but aren't a panacea.

They got rid of the variable-incidence part?

 

[F-14ATomcat]

I have constantly encountered this statement, and it always felt iffy to me. Is this actually true? Can anyone actually point to what advancements have reduced the need for swing-wings? I feel like, when we look at famous swing-wing aircraft (F-14, Su-25 Tu-160) we see the same patterns: T/W way less than 1, incredibly broad flight envelope from loitering, to supersonic flight and huge range.

I feel like there's no recently designed aircraft with this set of requirements, modern aircraft tended to mostly designed for either low-to medium speeds (F-35) to medium-to-high ones (F-22).

If you came up to a designer and asked him to design an aircraft today that can do all the same things an F-14 or a Tu-160 can, I doubt they could make one without swing wings. True, modern engines have better T/W than ones in the 70s, but I doubt that alone would compensate.

In life like in aerodynamics, any step in one direction means you lose another direction.

If you choose left you lose right, if you go up you are not going down.

That is the same in aerodynamics, Variable geometry wings are the same, modern aircraft can achiefve STOL with thrust vectoring nozzles, swiveling engines, such as V-22, each and every technology has advantages and disadvantages.

However when designers adopt a technology they need to consider their needs and prioritize what is the best for their aircraft needs.

Variable geometry wings are fine as long as the design really needs it.
Current aircraft do not need them, for example if you compare F-14 a naval fighter versus Rafale M you can see the VG wing on F-14 is maintanance intensive and adds heavy extra weight, canards do not replace VG wing advantages in STOL but if you add very light materials on Rafale the need for VG wing simply disappears since a light airframe can generate enough lift for slow speed landings and short take offs

A straigh wing is the best for lift at low speeds but not the best for high speeds, Deltas are the opposite, so priorities mean, other technological solutions to reduce disadvantages.

the Canard on Rafale adds lift at low speed, while the wing box and pivot of the swiveling wing in F-14 adds weight and since the wing is not fixed is relatively weakly joined to the fuselage, so both systems have disadvantages, but an engineer will decide what other technologies might help to reduce the disadvantages.


Another disadvantage of VG wings is stability due to the center of lift moving as the wing is sweep.
On F-14 they tried to fix it with wing gloves vanes so at the end it is a highly complicated aircraft mechanically speaking, so Rafale is up to some degree a simplier aircraft, and simplicity helps maintainance.


In few words is not only a single technology what matters but a combination of technologies that will decide what technologies an aircraft will use.

 

[F-14ATomcat]

I have constantly encountered this statement, and it always felt iffy to me. Is this actually true? Can anyone actually point to what advancements have reduced the need for swing-wings? I feel like, when we look at famous swing-wing aircraft (F-14, Su-25 Tu-160) we see the same patterns: T/W way less than 1, incredibly broad flight envelope from loitering, to supersonic flight and huge range.

I feel like there's no recently designed aircraft with this set of requirements, modern aircraft tended to mostly designed for either low-to medium speeds (F-35) to medium-to-high ones (F-22).

If you came up to a designer and asked him to design an aircraft today that can do all the same things an F-14 or a Tu-160 can, I doubt they could make one without swing wings. True, modern engines have better T/W than ones in the 70s, but I doubt that alone would compensate.

Aerodynamic studies are always made using some conditions, for example if they compare two canards of different swept, the rest of its features are the same, however when designing an aircraft it is a combination that will decide what set of technologies are needed to be used.

Tu-160 is still in production, the first question is why?
technically B-2 as a stealth machine is far much modern and needed, but Tu-160 is fast, and has cruise missiles good enough to be fire out of the reach of enemy air defences.

The logic of why it is still in production is based upon advantages and disadvantages.
It is a very fast machine, VG wings allow high speed at altitude and low speed landings at the same time.

The F-14 was simply retired because it was expensive to operate, I mean you have a modern aircraft in production with VG wings the Tu-160, simply because still represents a good solution based upon economics and performance.

To say a B-2 is better will depend for what, speed? no, stealth? yes each aircraft has a function, even an agrcultural aircraft has advantages a stealth fighter has not, everything depends for what? for flying very low and slow almost near the ground an agricultural aircraft is better, for evading radar and downing aircraft the stealth fighter is better.

 

[Hanz2k]

Tu-160 is still in production, the first question is why?

Don’t want to disappoint you, but the reason is that Russia is just not able to produce anything more advanced. They never acquire domestic knowledge about large composit structures manufacturing process. Look at famous Su57 wing bolts - this make the picture of the state of Russian airplane design capabilities. They want to go stealth with PAK DA, which based on rumors was B2-esque flying wing design. But it was too much for Russia.

They are trying to play around Tu160 airframe deficiencies with new cruise missiles with 6500km range just to give it some fighting chance.

 

[paralay]

What are the disadvantages of the Tu-160 airframe?

The percentage of materials in the design of the Su-57 airframe:
aluminum alloys - 40.5 - 44.5 %,
titanium alloys - 18.6%,
composites - 22 - 26%.

The percentage of materials in the design of the F-22 airframe:
aluminum alloys - 16 % ( for the prototype - 32 % ),
titanium alloys - 39 % ( 27 % ),
composites - 24% (21 % ).


composite wing of the MS-21 liner

 

[Hanz2k]

- F35 - 35% composites.
- Eurofighter Typhoon - 40% composites.
- A350XWB - 50% composites.
- B2 bomber - around 80% are different forms of composites.