AIM-120C

Because the AIM-120C has clipped wings and fins, does the "120C" give up any maneuvering ability compared to the AIM-120B? Are the clipped wings and fins increased in other dimensions to give the missile the same total area for these control wings and fins?

Adrian

Regardless of whether it's slightly less maneuverable in a certain region of the flight envelope, the AIM-120C is obviously a less draggy missile than the AIM-120B. Less drag means more speed and range. More speed means more maneuverability too, so the AIM-120C should be going faster than the AIM-120B when it intercepts a target. If it's not going faster than an AIM-120B at the end-game stage, that means it's trying to intercept a target that would have been outside the AIM-120B's range. I suppose the only place an AIM-120B might have an advantage is at really close ranges where its bigger fins *might* be able to generate greater axial/normal forces and pitching moment. But we're talking really close range where the thing's rocket motor is still burning. Overall, the AIM-120C is probably a more capable missile in terms of aerodynamics. Having really huge fins for sharp turns doesn't necessarily make a better, more lethal A-A missile.

avon1944 wrote:Because the AIM-120C has clipped wings and fins, does the "120C" give up any maneuvering ability compared to the AIM-120B? Are the clipped wings and fins increased in other dimensions to give the missile the same total area for these control wings and fins?

Adrian

You've seen too many movies. How many g's does a missile need to pull to hit a target that doesn't know its been fired upon until its too late to react? If you're a baseball fan like me, then you know how difficult it is to hit a 99mph fast ball... Now imaging trying to react at EXACTLY the right moment to avoid being hit by an aim-120 thats closing speed is over mach +3. Those couple inches of fin don't matter that much. Lights out and game over.

fox100 wrote:

avon1944 wrote:Because the AIM-120C has clipped wings and fins, does the "120C" give up any maneuvering ability compared to the AIM-120B? Are the clipped wings and fins increased in other dimensions to give the missile the same total area for these control wings and fins?

Adrian

You've seen too many movies. How many g's does a missile need to pull to hit a target that doesn't know its been fired upon until its too late to react? If you're a baseball fan like me, then you know how difficult it is to hit a 99mph fast ball... Now imaging trying to react at EXACTLY the right moment to avoid being hit by an aim-120 thats closing speed is over mach +3. Those couple inches of fin don't matter that much. Lights out and game over.

You know that brings up something I've wondered about on and off over the years but with the F-22's pretty much 360 degree IIR missile warning system has it ever been looked at to have the aircraft fly the evasive manuever itself? Seems with the computers running the show (and being able to think faster) for the last few seconds of the incoming missile's flight that it might be more effective at generating a miss than the pilot. Just a thought.

sferrin wrote:

fox100 wrote:

avon1944 wrote:Because the AIM-120C has clipped wings and fins, does the "120C" give up any maneuvering ability compared to the AIM-120B? Are the clipped wings and fins increased in other dimensions to give the missile the same total area for these control wings and fins?

Adrian

You've seen too many movies. How many g's does a missile need to pull to hit a target that doesn't know its been fired upon until its too late to react? If you're a baseball fan like me, then you know how difficult it is to hit a 99mph fast ball... Now imaging trying to react at EXACTLY the right moment to avoid being hit by an aim-120 thats closing speed is over mach +3. Those couple inches of fin don't matter that much. Lights out and game over.

You know that brings up something I've wondered about on and off over the years but with the F-22's pretty much 360 degree IIR missile warning system has it ever been looked at to have the aircraft fly the evasive manuever itself? Seems with the computers running the show (and being able to think faster) for the last few seconds of the incoming missile's flight that it might be more effective at generating a miss than the pilot. Just a thought.

Interesting and plausible I guess...The Typhoon already has a "Bitchin`Betty" which tells the pilot what action to take in terms of maneuvering the airplane when under missile attack. If the aircraft can generate those commands from the DASS, it isn`t a stretch to imagine a fully automated system.
Kind of a difficult one for pilots to get their head around I would have thought. Would you trust a computer which has more S.A. than you to pull you out of the s"@t?

It's pretty difficult to actually see an incoming AIM-120. It's not like an SA-2 which was the size of a telephone pole. Even if its motor is still burning, it doesn't leave a smoke trail. If it's motor has burned out (which is quite likely), you're not going to see much of anything until it's too late. Evading an AIM-120 in the real world basically consists of reacting to an aircraft that has the capability of firing one as though it has fired one. If you don't detect the aircraft that might have fired an AIM-120 at you, you'll have to have enough energy/speed to drag it out or outmaneuver it based on what your RWR tells you regarding the locating (usually just bearing) of the AIM-120's active radar seeker head. This is enough to either keep the missile on your 3/9 line in hopes that you can force it to bleed off enough energy pulling lead pursuit such that it can't pull enough G to intercept your aircraft at end-game or to put the missile on your 6 and attempt to drag it out.

Perhaps there are classified missile warning systems on fighters these days that can pinpoint exactly where incoming missiles are in relating to your aircraft. I'd be impressed if there were. As it is right now, however, all a pilot really has to go on in defeating an incoming AIM-120 or similar missile is his RWR, situational awareness of potential AIM-120-capable shooter aircraft, and speed. As for all this talk of AIM-120s doing Mach 3+ at the end-game/terminal guidance phase of the intercept... unlikely. Unless you're firing at a target coming straight at you at relatively close range, the AIM-120 isn't going to be flying anywhere close to its max rated speed at end-game. This is especially true if you're talking about a low altitude intercept. AIM-120s may do Mach 3-4 at high altitudes, but not down low. Range and speed are significantly reduced at low altitudes relative to high altitudes. And it's important to remember that once the missile's rocket motor burns out, it's decelerating. If its rocket motor has burned out and it's pulling high G lead pursuit, it's decelerating rather quickly. Let's not tread the AIM-120 as though it's some super missile that hits its targets no matter what. Like any other missile, it has to be fired within the right parameters to ensure a kill on a fast mover.

Raptor_One wrote:Perhaps there are classified missile warning systems on fighters these days that can pinpoint exactly where incoming missiles are in relating to your aircraft. I'd be impressed if there were. .

Modern RWR and defensive suites can give you range/bearing and speed if we believe the advertising brochures. Check out the systems on the Gripen for example which are publicly quoted as being capable of such....If the Typhoon can give maneuvering guidance on the fly to a pilot with an AAM on his/her tail, the detection/ranging capabilities of these gizmos`becomes pretty obvious.

SARH missiles have to be guided first until within seeker range, fighters have a whole host of goodies designed to detect datalink signals and other discreet comms` guidance. I cannot comment on their effectiveness though.

I think from what I have read on the forum from real deal pilots, it is perfectly possible to "out think" and out-maneuver a missile. That is without even thinking about active countermeasures such as towed decoys/chaff/flares.

Like I said, you have to be able to actually see something in 3 dimensions to effectively outmaneuver it. You're not going to see an AIM-120 with the naked eye very well. And unless you have some virtual reality helmet tied into sensors that can see a relatively small missile like the AIM-120 at a much longer range than the human eye, you won't be pulling advanced maneuvers to defeat it. The whole idea of outmaneuvering a small A-A missile comes down to sensors, including your own eyes. If they're not good enough to see exactly what the missile is doing far enough out for you as the pilot to react effectively, you won't be able to counter it with fancy flying. You'll have to rely on brute force tactics like just flying really fast while keeping the missile on your 3/9 line or putting the missile on your six and flying really fast down on the deck. Eventually you'll bleed the missile of energy like this if you start your counter maneuver early enough. You can do these maneuvers by simply knowing the missile's bearing. I don't believe there's any helmet mounted display that gives you a virtual reality image of the real world showing you depictions of incoming A-A missiles at like... 20 miles. If you had that, and the display was updated at a fast enough rate, you could literally outmaneuver incoming A-A missiles. I believe this level of sensor fusion and man-machine integration is 20 years into the future.

Raptor_One wrote:Like I said, you have to be able to actually see something in 3 dimensions to effectively outmaneuver it. You're not going to see an AIM-120 with the naked eye very well. And unless you have some virtual reality helmet tied into sensors that can see a relatively small missile like the AIM-120 at a much longer range than the human eye, you won't be pulling advanced maneuvers to defeat it. The whole idea of outmaneuvering a small A-A missile comes down to sensors, including your own eyes. If they're not good enough to see exactly what the missile is doing far enough out for you as the pilot to react effectively, you won't be able to counter it with fancy flying. You'll have to rely on brute force tactics like just flying really fast while keeping the missile on your 3/9 line or putting the missile on your six and flying really fast down on the deck. Eventually you'll bleed the missile of energy like this if you start your counter maneuver early enough. You can do these maneuvers by simply knowing the missile's bearing. I don't believe there's any helmet mounted display that gives you a virtual reality image of the real world showing you depictions of incoming A-A missiles at like... 20 miles. If you had that, and the display was updated at a fast enough rate, you could literally outmaneuver incoming A-A missiles. I believe this level of sensor fusion and man-machine integration is 20 years into the future.

Just have a button on the dash that says "Hyperspace" and let the computer figure it out for you.

I'm sure it would be possible for the on-board A.I. (you wouldn't call it just a "computer" if it could maneuver the aircraft to evade a missile) to do a decent job flying an aircraft in all sorts of combat modes. The problem is sensor coverage. If the AI doesn't have sensors available to literally "see" targets like a pilot would, it won't be worth squat. The A.I. in Falcon 4.0 (recent versions) is actually pretty good given the relatively limited computing power it has to work with. If you had a dedicated processor you could offload all A.I. functions to, you could program it to do all sorts of interesting things in real time. The thing about a combat flight sim like Falcon 4 is that the A.I. DOES in fact have the ability to "see" a wide variety of things just as a human flying his virtual jet does. In fact, to make the AI behave more realistically, you have to code in all sorts of limits and whatnot on what it can see, when it can see something, what alerts it, and so on. It's the opposite with an AI in a real aircraft. You have to give it a lot of different sensor data to work. You also have to make it work with that sensor data in a human-like fashion. Oh... and although the AI in a combat flight sim like Falcon 4.0 is decent, a good virtual pilot can still smoke it 10/10 times.

It would be useful to have an on-board A.I. to pilot the aircraft in cases where the pilot lost consciousness, was injured, etc. Oh, and if the AI can see the missile well enough to evade it, there's a way to display that sensor data to the pilot so that he can make similar or better tactical decisions. AI can beat a grand master chess player, but only after the grand master starts getting tired and loses concentration. In that sense, having an AI would be good in case the pilot was feeling really out of it (GLOC, unforeseen medical condition, etc.).

Clipped wings are there only to provide space for the internal bay of F-35 and F-22. The factory decided not to manufacture different variants for each plane in the eventory for commonality reasons. So you can remove 120 from an F-16 and place it onto the f-22. The extra range of the 120C is derived from compacted electronics wich allowed to extend the mottor a bit. Smarter software also provides optimized trajectories to provide less drag losses in flight.

Clipped wings were found to have neglible inpact on perfomance by themselves alone.

Pilotasso wrote:Clipped wings are there only to provide space for the internal bay of F-35 and F-22. The factory decided not to manufacture different variants for each plane in the eventory for commonality reasons. So you can remove 120 from an F-16 and place it onto the f-22. The extra range of the 120C is derived from compacted electronics wich allowed to extend the mottor a bit. Smarter software also provides optimized trajectories to provide less drag losses in flight.

Clipped wings were found to have neglible inpact on perfomance by themselves alone.

Do you have references to backup your claims here? In other words, can you cite articles, technical reports, etc.? Sorry, but I'm not going to take your word for it. If you can provide concrete sources to backup your statements, I will. Trust, but verify.

Aiforces monthly, Mike Spick and Bill Gunston Books. I got One particulary interesting "Great Book of modern Airplanes" Wich is a compilation of many other books. A-10, F-14, F-18, F-16, F-15, Stealth fighters, European fighters and Russias migs and Suckhois put together. In each teen fighter description theres detailed info about each weapon, AMRAAM Included. 2003 re-edition with updated material.

But the most detailed article I have comes from Airforces Mothly "ADVANCED AIR TO AIR MISSILES" (2 part report IN 2 seperate issue, this ones BVR) issue of September 2000 if Im not mistakened.(have to confirm this at home) And thats the one Im recalling in my previous post. It compares all past, present and future versions of the AMRAAM and the internal and external differences, perfomance improvments and with description of other missiles as well.

Plus I work in the aeronautical industry and I have some relations with the work being donne with MLU F-16's in my country.

Not all AIM-120's have extended rocket motors. It came about with the AIM-120C5 version which gave it the extended burn, faster intercepts and improved launch range, Thats also true about the AIM-120C clipped wings, it had to do with being put on other aircraft for internal carry. Of course now there is the C7 version and the AIM-120D.
.
Cheers,

ViperDude
(Former Lead engineer for A/A Weapons on the F-16)

Raptor_One wrote:It's pretty difficult to actually see an incoming AIM-120. It's not like an SA-2 which was the size of a telephone pole. Even if its motor is still burning, it doesn't leave a smoke trail. If it's motor has burned out (which is quite likely), you're not going to see much of anything until it's too late. Evading an AIM-120 in the real world basically consists of reacting to an aircraft that has the capability of firing one as though it has fired one. If you don't detect the aircraft that might have fired an AIM-120 at you, you'll have to have enough energy/speed to drag it out or outmaneuver it based on what your RWR tells you regarding the locating (usually just bearing) of the AIM-120's active radar seeker head. This is enough to either keep the missile on your 3/9 line in hopes that you can force it to bleed off enough energy pulling lead pursuit such that it can't pull enough G to intercept your aircraft at end-game or to put the missile on your 6 and attempt to drag it out.

Perhaps there are classified missile warning systems on fighters these days that can pinpoint exactly where incoming missiles are in relating to your aircraft. I'd be impressed if there were. As it is right now, however, all a pilot really has to go on in defeating an incoming AIM-120 or similar missile is his RWR, situational awareness of potential AIM-120-capable shooter aircraft, and speed. As for all this talk of AIM-120s doing Mach 3+ at the end-game/terminal guidance phase of the intercept... unlikely. Unless you're firing at a target coming straight at you at relatively close range, the AIM-120 isn't going to be flying anywhere close to its max rated speed at end-game. This is especially true if you're talking about a low altitude intercept. AIM-120s may do Mach 3-4 at high altitudes, but not down low. Range and speed are significantly reduced at low altitudes relative to high altitudes. And it's important to remember that once the missile's rocket motor burns out, it's decelerating. If its rocket motor has burned out and it's pulling high G lead pursuit, it's decelerating rather quickly. Let's not tread the AIM-120 as though it's some super missile that hits its targets no matter what. Like any other missile, it has to be fired within the right parameters to ensure a kill on a fast mover.

Well, I agree w/most of what you say except about the KE or the equivalent speed of the slammer (I think you guys call them slammers) on "impact".

With the fleet of F-22's only being about 182 or 183, the airplane is going to be used as a standoff platform and ie spend the majority of its time far away enough from enemy airfields to not get pounced on unexpectedly so from other fighters. As such there are 3 possible (I'll limit it to 3 for the sake of being brief) scenarios for a slammer launch from a F-22.

1) Head on (25%)
2) "Side" shot (50%)
3) Tail shot (25%)

So (and this is GREATLY simplified), you have 75% chance of an F-22 launching a slammer in a scenario in which the velocity of the target does not take away from the KE of the missile. You have a 25% chance of the velocity of the target aircraft reducing the equivalent velocity. Considering that we're talking about the supercrusing F-22 and the aim-120, you must take into account the KE that the launching aircraft will impart to the missile.

We're not talking about a F-15/16/18 (with external tanks and stores) who is launching the missile from 0.9 mach and 30k ft... We're talking about an aircraft that has the capability of launching its missiles at over 2.0 mach and at altitudes exceeding what those legacy platforms are going to be launching at, and thus you have the benefit of gravity also adding to the KE of the slammer. Thus the F-22 driver has the added benefits of A) altitude and its thinner atmosphere, and B) Gravity as the Raptor will most likely be flying higher than the target.

(And I don't care what anyone says about the official crusing speed or ceiling of the F-22. Read all the books you want but do the math for yourselves; the Buffs of yesterday didn't have pressure suit attachments in them because they topped out at 40 or 50k. Anyway....)

So yes, in all probability the aim-120 launched from an F-22 will be on the order of 3.0 mach.

And besides the point, whomever is right or wrong doesn't matter much here as the F-22/aim-120 combo is not something any pilot would want to go up against. Regardless of 2.0 mach or 3.5 mach, if you're just using your eyeballs because your radar is giving you sh*t information or no information at all, then you could be the ****** 6-Million Dollar Man and not stand a chance of avoiding a plane-missile collision as your human reaction time isn't going to be good enough. I also doubt that in whatever conflict happens (and it will happen) that the F-22 is going to be firing 1 missile per 1 target. More like 2/target for a higher probability...