Why are missiles always forward facing?

[Conure]

Hey guys, I was just looking up flight tactics in general and how it is important to manoeuvre enemy aircraft into LoS..Why aren't missiles (specifically AtA) on rotating racks which are adjustable in azimuth and altitude? Surely this would make sense as then the vehicle could attack from any angle. It'd take some immense situational awareness to keep track of this type of weapon system but surely some of it could be automated..

 

I understand this would in some cases impact on aerodynamics (eg of aircraft is in steady flight and the missile points directly down, suddenly you've got a missile shaped airbrake), but at the very least rotation in azimuth would work?

 

I know there are probably some good reasons why it's not so, given that the aeronautical engineers tend to be pretty smart..But my common sense tells me it should be possible!

 

Cheers

[Kuky]

not really, the missile has to start off flying into the wind and that is where aircraft is heading... actually some racks are little facing inwards and downwards but that's because the airflow in that area is in same direction (air around airframe/wings does not travel in parallel)

 

But while on this subject I've been wondering why don't they make a radar dome that can rotate more so that it can face 90° left/right so that it can allow your aircraft go into a beam without loosing lock

Edited January 22, 2011 by Kuky

[Conure]

not really, the missile has to start off flying into the wind and that is where aircraft is heading... actually some racks are little facing inwards and downwards but that's because the airflow in that area is in same direction (air around airframe/wings does not travel in parallel)

 

But while on this subject I've been wondering why don't they make a radar dome that can rotate more so that it can face 90° left/right so that it can allow your aircraft go into a beam without loosing lock

 

Why does it have to start facing into the wind? I understand that if the aircraft is doing 350 knots then the missile will accelerate at 350 knots + whatever the rate of acceleration is, but presumably it would be chasing a target also moving at a similar speed which negates said acceleration advantage. Similarly if firing backward at a target on your own tail the missile would accelerate entirely under its own energy, however this would be toward a target moving toward the missile at (eg) 350 knots, negating velocity advantage resulting from forward facing flight..At the very least this would force evasive action from attacking craft and force it off the tail.

 

Maths was never my strong point though...I won't even pretend that I'm proposing some kind of viable formula! lol..

[104th_Crunch]

They have been jets with rear facing missiles. The Su-34 has rear facing missiles and radar.

[Kuky]

With rear facing missiles there is an issue of zero velocity, how they solve that I don't know, I guess the missile goes through that stage very quickly so zero airflow over its control surfaces is not an issue, probably they have designed special contror surface shape for that exact situation?

[GGTharos]

It doesn't negate that advantage. In fact it would turn into a dis-advantage, and this is why there are no operational rear-firing missiles. The useful ranges was too short, and you have up two racks to shoot someone who got on your tail - ie. you lost the fight. At this point you're not likely to survive, and aiming a missile that's pointed behind you is not exactly easy. In general your aircraft is geared to attack stuff in front of it, though lately attack foot-prints have been expanding and some weapons are capable of covering the entire azimuth for attack.

 

It just gets too complicated to have rotating missile launchers, and useless as well. The aerodynamic impact is quite significant.

 

Why does it have to start facing into the wind? I understand that if the aircraft is doing 350 knots then the missile will accelerate at 350 knots + whatever the rate of acceleration is, but presumably it would be chasing a target also moving at a similar speed which negates said acceleration advantage. Similarly if firing backward at a target on your own tail the missile would accelerate entirely under its own energy, however this would be toward a target moving toward the missile at (eg) 350 knots, negating velocity advantage resulting from forward facing flight..At the very least this would force evasive action from attacking craft and force it off the tail.

 

Maths was never my strong point though...I won't even pretend that I'm proposing some kind of viable formula! lol..

[159_Archer]

As we know, all AC have to be thoroughly tested in all aspects of their operations, and that includes the use of all the munitions and equipment pods they carry. AFAIK this is why some A2G missiles/weapons are loaded onto ejector rails to ensure they seperate properly, and not just stuck onto any-old simple rail.

 

I'm sure the engineers involved will have considered anything like the above -if it was likely to be be feasable. I know the Russkies did experiment with a rearward facing R-73 (IIRC) for defence-purposes, but don't think they use it thus.

 

I would image trying to launch most ordnance 'sideways' or similar from any fast-mover would result in damage, or possibly death! When you consider the forces involved and think about what direction the weapon would take from the rail upon firing, I'm sure the first fraction of a second is determined by the oncoming air-flow. Probably shove the missile straight into the wing!

[GGTharos]

Thrust vectoring.

 

With rear facing missiles there is an issue of zero velocity, how they solve that I don't know, I guess the missile goes through that stage very quickly so zero airflow over its control surfaces is not an issue, probably they have designed special contror surface shape for that exact situation?

[effte]

First off, aerodynamics. As pointed out, the missiles need to be streamlined on the rails. Having them pointed nose into the wind ensures this without adding complexity to the design.

 

Second, sensors. You can't fire a missile off blindly - it needs guidance and/or lock. The sensor suite of a fighter, including the eyes of the pilot, has traditionally (and for good reason) been pointed mainly forward. The missile's own seeker will naturally be limited in the rear hemisphere.

 

These days there are several missiles which, when combined with helmet-mounted sights or other off-boresight targeting systems, can engage targets off the nose of the aircraft. This is not done through pivoted pylons though, but rather by making the missiles manoeuvrable enough to allow them to turn around once off the rails.

 

I think the Soviet R-73 was the first. It by far predated the later western alternatives, and had NATO and the rest of the world seriously concerned.

 

I also present to you... the AIM-9X, complete with cheesy music*.

 

Then there's the IRIS-T, seriously impressive bit of kit!

 

Israel have the Python-5, and there are a couple of others which I think have off-boresight capability to various degrees. More than you want to know about it on Wikipedia, I'm sure. :)

 

*) Now we know what the musical talent behind Iron Eagle 3 did once he got fired and his citizenship revoked for his sins (i e taking part in the creation of that movie).