Why are swing-wing fighter jets obsolete?

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Why are swing-wing fighter jets obsolete?

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Anonymous 0 Comments

At the time, variable geometry wings were a popular solution to the problem of wanting to reduce drag at transonic and supersonic speeds, whilst maintaining lift at low speeds. The trade-off is this moving part is vulnerable to wear and tear or failure, and is not good for stealth.

The modern focus is on stealth/low observability aircraft to protect the crew and increase mission success.

Anonymous 0 Comments

Swing wings were also designed before computers were powerful enough to handle the aerodynamic simulations required to design modern wings. These improved aerodynamics have made swing wings all but obsolete, since the aerodynamic benefits of a swing wing can usually achieved now in a fixed wing. The added weight and complexity of a swing wing is thus unnecessary.

Anonymous 0 Comments

Variable-sweep wing are very good at what they do. Allow the plane to have increased maneuverability and efficiency in both high and low speed.

The problem is that, the modern fighter doesn’t necessarily need that increased maneuverability at low speed. No matter how cool it is, dogfights are a thing of the past. Missile technology have improve a lot and are not just too dominant and they shaped the tactics of pilots. Missile also made anti-air defense extremely difficult to fight over, staying as far as possible of heavy anti-air defense is extremely important. Flying at low-speed would be extremely risky anywhere where air dominance isn’t already acquired.

Stealth is becoming a major factor in fighter design and well for that you need specific shape. A variable sweep-wing would just be extremely inferior to current design in term of stealth. Stealth is not just about staying invisible, but also making it harder for the enemy to lock on you and shoot you down.

Some people talk about moving parts are vulnerable, added weight are complicity. They are right that those things exist, but they are not a factor in why sweep wing are not longer used. If sweep wing were providing an important capability, the designer would just work with the added weight and complexity. Look at the F-35B, the fan is extremely vulnerable, add a lot of weight and is complex, but it provide the F-35B with an advantageous capacity that made those drawback worth it. The advantage of sweep-wing are just not worth it in the current battlefield.

Anonymous 0 Comments

Why adjust wing sweep when they can just adjust thrust vectors?

The F-14 needed the low speed lift specifically for carrier landings and takeoff, the maneuverability was a bonus. The F-35 variants used on carriers today can just takeoff vertically.

Anonymous 0 Comments

There’s one basic problem that swing wings were intended to solve.

First is the ability to generate lift while moving relatively slowly. For example, when taking off from an aircraft carrier.

Second is the ability to minimize drag when flying supersonic. For fuel efficiency but also to enable them to go really, really fast.

The problem is that you want an aircraft that is able to take off from an aircraft carrier, but also travel really fast. It was a kind of “you can do A or B but not both” kind of problem.

So they invented a wing that could move. That solved the “you can’t do both” part of the problem because now you can move the wing so that it CAN do both.

And then computers got much more powerful and we were better able to model the forces involved in both slow speed and high speeds and we were able to figure out a single wing that is able to handle both kinds of flying.

So once we figured that out, having a moveable wing is just extra parts that can break. So there’s no point in doing it that way anymore.

Anonymous 0 Comments

TLDR: we’re better at designing wings now, we have better materials, but mostly stealth.

Stealth is the real answer to the question. Having a moving wing is very bad for an aircraft’s radar cross section so modern fighters like the F-22 and F-35 have been forced to abandon the concept outright.

But other newer non-stealth aircraft have also preferred a fixed wing lately, so why is that?

Swing wings were a solution to allow aircraft to fly at lower speeds to maneuver and take-off and land, then swing to a low drag mode for flying at super sonic speeds.

Modern simulation software and material science (composites) has improved so much that we can make wings that have better flight characteristics without needing to swing.

The way fighters operate has also changed. For example speed used to be much more important than it is now. During Vietnam they realized that pilots rarely exceeded mach 1 because it just burned too much fuel. So modern jets are slower than before but way more efficient, able to cruise at supersonic speeds without the afterburner.

Missile technology has also improved a lot. Dogfighting is not obsolete, but it’s nowhere near as important as it was in Vietnam.

There’s an argument to be made that swing wings were also heavier and difficult to maintain, but to paraphrase a Youtube aviation engineer “Who cares, the benefits outweigh the downside. Maintenance on stealth aircraft is much much worse anyway and that didn’t stop them now did it?”

Anonymous 0 Comments

They make the aircraft more complex, resulting in it being much more expensive to operate and requiring a lot more maintenance to fly. The main advantage is that they can give you wing geometry that works well for both good low-altitude subsonic and high-altitude supersonic flight characteristics.

One of the main factors in why they’re obsolete is that aircraft are no longer the primary launch platform for most nuclear weapons. Every known nuclear-armed state besides the United Kingdom still keeps some that are launched from aircraft, but ballistic missiles launched from land and submarines are now more strategically important for most of them (exceptions may or may not include India, Pakistan, Israel, North Korea).

Let’s take two aircraft as examples:

1. The B-1 Lancer was designed to replace the B-58 Hustler (retired in 1970) in a supersonic nuclear strike capability. It was originally cancelled because of the expectation that they would have the B-2 with stealth capabilities that would be more useful than speed in precision nuclear strikes. However, because of the delay in B-2 development and the fact that it was so expensive, the US Air Force bought 100, the last of which are scheduled to be retired in the next few years. Its nuclear strike role was removed and it was repurposed for carrying huge amounts of conventional munitions, which it proved to be extremely capable of doing (it was the main aircraft in terms of munitions expended in Iraq and Afghanistan, alongside the much more numerous F-16). However, a multi-role fighter can do this fairly well and if you do need the greater range or munitions capacity of a bomber, the US Air Force typically likes to address both of those by putting more jets in the air, whether it’s a refueling aircraft to extend the range or more fighters to carry bombs. And both refueling aircraft and fighters have a wider range of stuff that they can be used for than a supersonic bomber.

2. The F-14 Tomcat was possibly the last true interceptor, definitely the last naval interceptor. The primary role of an interceptor is to take off, climb fast, and fly fast in a straight line at bombers. The expected main threat to a US Navy carrier group in the 1960s was in the form of the Tu-22M bomber (another supersonic variable-sweep wing aircraft), and the expectation was that in a strike against a carrier group (a carrier group is a carrier plus a few cruisers and destroyers whose job is to keep it safe, with cargo ships and maybe a submarine following it around), a certain portion of the missiles fired would have nuclear warheads. Taking a nuclear strike would be highly inconvenient for the operations of the carrier group, so they wanted something fast enough to engage fast incoming aircraft. The expansion of satellite and cyber reconnaissance coverage to a much greater degree than existed in the 1960s means that it’s possible to detect this kind of strike no later than when the planes take off, rather than possibly not before it’s close enough to appear on radar, so speed is less important (plus, the missiles fired by fighters are fast enough anyway).

Anonymous 0 Comments

Old: Engine big, engine no power even if big, we sweep wings to get faster for a big extra cost.

New: we don’t need super speed anymore because die aniway. We need super cruise, range; the big engine now also has the power and fuel economy to do so. Sweet wing cost much but gives marginal benefit.

Anonymous 0 Comments

There is also a big weight cost for variable-geometry wings. Complexity, cost, weight, maintenance – The technology can’t buy its way on the airplanes anymore.

Anonymous 0 Comments

Swing wing allowed aircraft to go slow and fast. The F14 is still the fastest navy aircraft ever. But we decided stealth is important and speed is not so important so we started optimizing for other things instead.