Why don't fighter jets have missiles that fire backward?

Factual Questions
1

This might seem silly, but I recently heard about a fighter jet which was capable of launching air-to-air missiles in different directions, so that it could fire one at a pursuing plane.

This made me wonder- why did it take so long to think of this? What is so hard about having air-to-air missiles that fire backwards? One of the biggest limitations of a fighter jet seems to be its ability to acquire a target before its opponent does. In maneuvering, each jet tries to set up a firing solution against the other. This is because each plane can only fire at a target in front of it…which is limiting.

Why spend so much effort on maneuverability? Wouldn’t it be simpler to develop long-range air-to-air missiles which can be fired in different directions? No matter where a bogey is, you can plug him, no need for fancy high-G maneuvers because your firing arc is much larger than his.

2

This is a WAG, but a forward-launched missile (or cannon shell or bullet) adds the velocity of the plane to the speed its propellant gives it. Rear-launched weapons would have to overcome the plane’s forward speed to get up to speed in the opposite direction. This would be wasteful of missile fuel, thus reducing the weapon’s effective range.

3

Well, for one thing firing backward complicates the control and stability problem. If you fire backwards there comes a time when the airframe has zero velocity relative to the air mass and this, for a guided missile, can be somewhat awkward. How do you maintain attitude and control through the region of very low airspeed and when the direction of airflow over the control surfaces reverses?

Ground launched missiles and rockets have this problem and for guided missibles some sort of rail is provided and the only thing that is done for a while is to prevent instability with no guidance provided. Or the missile can have control surfaces in the rocket exhaust like Polaris, or a controllable nozzle on the motor, or something. But these are all complications because they are in addition to aerodynamic control which is required unless the rocket motor burns all the way to the target.

4

Several airforces now use a helmet mounted sight to control the seekerhead of infrared-guided AAMs. The Israelis pioneered it, and it seems to great stuff for dogfighting, since you no longer have to ‘point’ your plane to get a lock. Still, the engagement envelope is limited. No launching ‘up’ or anything like that.

Short-range AAMs have very short ‘burn times’, and coast for most of their flight. That means they lose energy the further they go, and each manuever they perform drains still more energy. This limits what they can do. The most manueverabe (Python3, Aphid) have very short ranges (several kilometers), and the longest ranged ‘short range’ missles (Aim-9X) are not as manueverable.

Modern fighter develpment doesn’t leave a lot (any) of room for rear-facing radar. How else could a rear-firing missle be targeted?

The Russians played around with this concept, sort of. They developed ‘Air to Air Cruise Missles’ to go after our AWACS planes. These were to be launched from a EW variant of the Su-24 Fencer, which would use it’s electronics suite to find the AWACS (not hard, since they would be almost constantly transmitting) and then launch off a modified cruise missle, which would home in on the AWACS transmissions. Useless against a fighter, but against a airliner with a massive disk on top, who knows? Like much Russian gear, it was probably a great idea, poorly executed.

The big problem with BVR (beyond visual range) missle engagements is identifying the target. This is a bigger problem for America than for most, since it is fair to assume that most aircraft in a given theater will be ours. Figure the same problems when shooting backwards.

Still, an offshoot of the late Cold-war Tacit Rainbow program was a air-air cruise missle, a Phoenix replacement, of sorts. Dunno if that is still going on, given that the AMRAAM/Sidewinder-X combo is top of the herd for the forseeable future.

5

I don’t see why a missile launched forwards can’t be arced around to hit a target behind the jet. Missiles can make turns that would incompacitate a human. All it would take is for there to be a target lock computer on the jet with a camera facing backwards. Surely someone has to have thought of this…

6

First off, a big congrats to Brutus for the line of the week:

Like much Russian gear, it was probably a great idea, poorly executed.

Awesome!

Now, to the OP. David Simmons, Brutus and Thaumaturge have all provided excellent posts.

But to the OP: remember, if you are shooting missiles out the back of a fighter, you have LOST the fight!

Seriously, the US doctrine is to identify and kill the enemy BVR whenever possible. Using a combination of AWACS, EA-6Bs (and soon-to-be EA/F-18s), the fighters get a look, get a lock and then shoot. If you miss with a radar shot, throw out a heater (Sidewinder) that is better at close range. When you get inside missile range, use the gun. If (and ONLY if) the enemy gets behind you, throw out chaff (for radar-guided missiles) and flares (for IR guided missiles) and call on the radio for your buddies to target the bastard on your ass.

The aft-facing missile would be a last-ditch effort to save yourself. By flying with it, you would essentially be assuming that every line of defense provided to you was going to fail, and you would need to shoot a missile backwards.

I don’t think anyone in the USN or USAF would actually take off with one of those installed. (The USMC is excepted because they don’t normally know which end is forward, so they’d take off with anything installed). :wink: (Standard Marine dig, sorry)

Note: this post did not address the technical issues of aft-facing radar or IR sensors (difficult), as well as fire-and-forget missiles that can pull 15 Gs in a turn to intercept a target behind you (easy).

7

This seems like a perfect application for externally mounted, rear facing lasers. These could “blind” the pusueing pilot or the optics on his plane (they wouldn’t have to be of sufficient strength to actually damage the plane itself). I’ve always thought that “explosive chaff” would also be a good last minute counter measure to throw of pursuing planes.

8

Chaff is extremely effective and is used by almost all aircraft that go into combat. Its purpose is to confuse radar-seeking missiles by providing a very large, reflective radar target.

As for aft-facing lasers: how are they targeted? The effectiveness of chaff and flares is that they spoof the missile from every angle; a flare is really bright and hot from any way you look at it. A batch of chaff is likewise really reflective from any way a radar looks at it.

A laser, being an extremely narrow focused beam, would only be useful in the precise area that it was aimed. What is used to aim this laser? And once aimed, how does it maintain its target? If a fighter (or any airplane) gets targeted from behind, expect violent maneuvering in order to disrupt any missile solution. An aft-facing laser system would have to be able to compensate for rapid 9g onsets from the target aircraft as well as maintaining the track of the pilot’s eyes of the pursuing aircraft (which is also maneuvering).

Someday this maybe feasible, but the technology does not exist today to make this possible, much less deployable in combat.

9
      • I would also note that most aircraft missile engagements -usually- take place when the opposing aircraft are dozens of miles from each other. Strategists prefer to have planes lay back some distance and fire missiles, and let the missiles do the dogfighting–it works better.
        ~
10

Just for the heck of it, I’d like to mention that in both the book and the movie Firefox the titular MiG-31 (no relation to the real plane) has backward-firing missiles as well as forward-facing ones.

11

The old Russian Stormavik class ground attack aircraft from WW2 had a rear defensive gun position.

The Stormavik would make a low level attack with machinguns, autocannon, rockets & bombs, but would be vulnerable to fighter attacks during the run. The rear gunner was intended to defend against this, often very effectively.

Now, the Stormavik carried several tons of battleship steel armor, as a load-bearing part of its structural frame. This granted it immense strength. I have read accounts of Stormaviks taking multiple, direct-contact hits from German 88mm antiaircraft cannon, and not only surviving, but able to fly again with mere hours. :eek:

The explosive charge in an 88 mm shell is roughly equal to the one in a Sidewinder missile, except the Sidewinder is a proximity device–it goes off near the target, instead of hitting it.

Picture a WW2-type Stormavik, carrying tons of armor, but with the rear machine gun replced by a Stinger missile launcher.

If the craft can withstand contact hits from an 88, it can withstand proximity hits from a missile.

And the rear-firing Stinger missile could defend the craft admirably.

Does this mean that an upgraded Stormavik is now a viable combat aircraft?

12

At first I was thinking ‘why does it have to overcome forward speed and go in the opposite direction’? If the objective is to hit a pursuing aircraft, all you’d need is to reduce speed and the other aircraft would catch up to your missile. But the response is presumably that all missile guidance systems are designed around having positive forward airspeed… with the fins and what have you. They’d work backwards or not at all while the missile is still having air blowing past its base towards its nose, and that way there isn’t much chance that the second jet would actually hit it straight on - it would pass the missile to one side.

:stuck_out_tongue: Any chance you could design a missile with its fins on backwards?? :]

13

http://aeroweb.lucia.it/~agretch/RAFAQ/R-73.html

Found this.

Otara

14

You’ll notice that on fighter planes, the nose cone of the plane and missiles are all some form of Ogive tangent or Von Kármán variant pointing in the direction of travel. The shape of nose cones is massively important as you’re balancing drag and stability (and more) in sub- and super-sonic flight. The aerodynamic characteristics of a missile are important in both it’s effect on the plane when mounted and it’s ability to detach, accelerate and maneuver when fired.

To have a rear-facing missile mounted to a fighter’s wing, it would need some sort of “butt-cone” :wink: attached to the rear end of the missile, facing in the plane’s direction of travel. With the extreme acceleration rocket motors achieve overcoming the delta-V of the plane is not an impossible task, but you would need to scale up the rocket motor to overcome this negative velocity (call it f(orward)-V) start and some truly amazing flight control system to keep the missile steady as it’s flying backwards (r(ear)-V).

The missile is launched with a f-V equal to the speed of the plane. It’s accelerating at r-V, determined by the (rather large) rocket motors installed… I don’t know the exact speed these missiles accelerate, but considering their size and lack of pilot, I imagine they pull some HARD acceleration…

So again, missile is launched, f-V equal to plane speed, r-V equal to rocket motor impulse, accelerating towards the point where f-V and r-V cancel each other out and the missile, momentarily, would have zero speed relative to the earth and then would continue to accelerate towards the target.

Considering the speeds involved in a dogfight, the time the rear-fired missile would take to a) not fall out of the sky while whizzing backwards and b) start accelerating from zero towards the target, it best be a couple few many kilometers away for this missile to get it’s act together.

The mode of failure would definitely be in the “whizzing backwards” part of its flight… the entire missile would have to be designed so the fins work in both directions of flight and be capable to keep it aloft as it has a speed graph that looks like an AC sine wave.

MinutePhysics on YouTube did an excellent video that (partially) applies here… why it’s so hard to get to the sun from earth !!! All about rearwards velocity and overcoming it, do scope it out… Hitting the Sun is HARD - YouTube

I hope this helps some… this is my first post here so be gentle :wink:

15

There’s a treaty specifically banning blinding lasers so it would probably be politically unfeasible to make one of these. The strength to burn a human eye is low enough that it wouldn’t do anything noticeable to the plane.

16

It is clear that some posters need to check out the documentary, Firefox, narrated by Clint Eastwood. The re-enactment of Soviet dogfighting tactics and the use of rear-firing missiles is the most interesting part.

17

During the Iraq war, the USA accomplished a lot with combined forces & laser guidance: a soldier/resistance fighter on the ground aimed a laser at an enemy installation, and a plane dropped a bomb that homed in on that laser targeted spot.

Here, you’re having our own planes have their own laser on their rear. No need for combined forces; we have painted a giant target on our own planes for an enemy to aim at. The pursuing plane can just launch a missile and tell it to follow that laser.

Much of the technology today seems to be for ‘stealth’; making your planes invisible or indistinguishable from background clutter. Putting a blazing laser on the rear of your plane would seem to be the opposite of that.

18

You really think so? Seems like:

  • a standard laser pointer from the ground can easily blind pilots, thanks to the divergence
  • consumer drone gimbals already work pretty well, or gimballess laser trackers
  • the military already has optical target tracking capabilities, or radar-based trackers like the CIWS used on ships
  • they’re already working on more powerful lasers for tracking even faster objects (missiles), this would just be a much smaller version

There’s the whole blinding thing by treaty, but that only applies to permanent blinding, not temporary disruptions of vision, right?

19

pilot141 last posted in 2015. Just in case you were expecting a response.

20

Guess you can’t go very fast when you keep looking backwards :slight_smile: Thanks.