With the exception of the Panavia Tornado, fighters do not have thrust reversers. Why is this? Why does the Panavia Tornado have them?
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asked May 13, 2015 at 14:25
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$\begingroup$ The de.wikipedia.org/wiki/Saab_37 Viggen also uses thrust reversers. $\endgroup$– jklinglerCommented May 30, 2016 at 10:23
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5 Answers
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Thrust reversal is a complex system (equals money) and it uses significant amount of fuel (also equals money). It is not a very efficient means to reduce the speed of a landing aircraft either, and other methods (e.g. brakes or drogue parachutes) are much better suited.
The biggest advantage of thrust reversal is that it cancels out the idle forward thrust working against the aircraft. Canceling out idle thrust isn't an issue on most fighters, as they have an engine nozzle that is open at ground idle to prevent any thrust from being produced. This nozzle probably also makes it a bit difficult to integrate Thrust reversals, but the Panavia Tornado proves it can be done.
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$\begingroup$ ... saving fuel on reverse thrust but always taking off with full afterburner... I don't think so $\endgroup$– JanCommented Oct 25, 2019 at 6:41
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$\begingroup$ @Jan Rather than alluding what you think and downvoting, it is appreciated if you can provide some evidence. $\endgroup$– FarhanCommented Oct 26, 2019 at 15:49
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$\begingroup$ I can only speak for the civilian sector where a friend of mine who flies large commercial aircraft told me that their company instructed them to be light on the brakes and rather use full reverse thrust. You can always refuel but changing the brakes costs time during the turn around and thus a lot of money. Given the mission profile of military jet fighters - takeoff as quickly as possible, have air superiority at the target region by being as light as possible and having a higher thrust/weight ratio than the enemy - being economical is not top priority. $\endgroup$– JanCommented Oct 27, 2019 at 13:55
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$\begingroup$ In short the answer should be: Thrust reversal is a complex system which adds unnecessary weight which reduces the effectiveness of the fighter. Leaving it away reduces the turn radius and improves handling qualities of the fighter. $\endgroup$– JanCommented Oct 27, 2019 at 13:57
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$\begingroup$ It of course comes at the cost of having to change the brakes more often but better repair an aircraft after the fight than not having an aircraft after a fight. $\endgroup$– JanCommented Oct 27, 2019 at 14:01
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It has nothing to do with cost or wasting fuel.
A military jet is notoriously designed to do the best it can, to hell with how much it costs. If expense of construction was a concern, they'd think it was ridiculous to build from exotic components just to shave a few pounds.
Fuel efficiency and fuel cost is only a concern in terms of being economical as possible in order to have the best range to attack the enemy, or to loiter on station on patrol. Wasting a little fuel on landing is inconsequential; why else would jet fighters have fuel dumps? It's common to jettison any few thousand extra pounds of fuel to get landing weight down, and it's also common to take extra fuel on from the tanker just in case. So you take three times as much fuel as you need to get back to base, then when you get there safely, you just dump it so you're light enough to land.
They don't include reversers because the extra weight and space they need would be better used for something else like fuel or avionics.
Military jets, especially fighters, are ridiculously expensive to operate, not just buy. Commercial aircraft, on the other hand, need to do things cheaply, with little maintenance and short turn-around times. Passenger aircraft and airlifters are far larger and heavier than fighters; that's why they need reverse thrust. A big enough parachute is a real pain to pack back up again, and replacing worn out brakes is expensive. A thrust reverser is extra initial expense, but it pays for itself.
Military large airlifters use thrust reversers to quickly unload and return for more, and to land on short runways; that's rarely a concern for a fighter. They may also need to turn themselves around for takeoff; while a fighter could be pushed by hand in a pinch, a C-5 Galaxy, not so easy. It's not surprising, in the few fighters that have a reverser (the Tornado and the Saab Viggen), landing on short or icy runways was a primary motivation, coupled with rapid turnaround, and the fact that parachutes are only effective at high speeds.
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6$\begingroup$ Welcome to Aviation.SE Kel! If you could do us a favor and break down your one giant paragraph into smaller ones... It's a little hard to follow as it's currently structured. $\endgroup$– Jae CarrCommented May 30, 2016 at 2:20
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$\begingroup$ I agree with this answer. Fuel is dirt-cheap compared to everything else about a fighter, including operating costs. The reason is weight and space. Fighters need to be as light as possible for the sake of maneuvering. They also prefer to be a small target. Yes, the answer should be broken up into smaller paragraphs. But I upvote because I agree with pretty much every sentence. $\endgroup$– DrZ214Commented Jun 16, 2016 at 5:12
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Fighter aircraft are specialized tools optimized for a specific purpose: to destroy enemy forces (in the air and on the ground). Everything that is not vital to that mission is quite literally dead weight that reduces the performance of the aircraft as it relates to its specific purpose. Jet fighters are not required to "taxi back" on the tarmac, and simpler "speed brakes" are more effective at slowing down in flight.
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Fighter aircraft are specialized tools optimized for a specific purpose: to destroy enemy forces in the air and on the groundthe latter I would call them bombers, though, not fighters. $\endgroup$– FedericoCommented May 13, 2015 at 15:51 -
7$\begingroup$ @Federico: I think you will agree that many fighter aircraft have ground attack capabilities. $\endgroup$ Commented May 13, 2015 at 15:56
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$\begingroup$ that's the "fighter-bomber" mashup (of which the Panavia is a member). if we want ot be purists, no, fighters are not made to attack ground targets, if we include fighter-bombers then, instead, yes I agree with you. $\endgroup$– FedericoCommented May 13, 2015 at 16:03
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1$\begingroup$ @Federico The F-16.. What every pilot calls it (unless you're a C-model driver). $\endgroup$– user3309Commented May 13, 2015 at 19:11
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1$\begingroup$ As long as we're splitting hairs about role designation, the correct terminology is actually attack or strike. For example the F/A-18 is a fighter attack aircraft, and is also called a strike fighter. Just like the air force has the F15E strike eagle. In summation, everyone is wrong, and we're all retarded for even caring. $\endgroup$ Commented May 17, 2015 at 6:33
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The old Saab Viggen fighter also has thrust reversers. This was part of what made it so capable on short or improvised runways. Wasn't useful enough to keep in the Gripen that replaced it, that is a much more conventional 4.5 generation fighter.
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It is because they already have several ways of braking, so they don't need reverse exhaust.link This should explain to you the braking systems used by the f-16 instead of reverse exhaust. This jet you are describing may not have as many braking systems as a normal jet does so it uses reverse exhaust.
