SARH launch warning on RWR.

[fltsimbuff]

I just confirmed that the Phoenix does in fact have an inertial sensor system which is part of the guidance (not control) section.

Whether that translates to a functional INS, hard to tell.

 

I also confirmed that it uses both SARH and ARH modes, but not the usage mechanism.

 

Is the method used to confirm something you can share? I'd definitely like to learn more about its guidance system.

 

My assertion of poor terminal maneuvering performance is based on the fact it is gliding by the time it reaches a distant target. For High-flying targets it doesn't have a ton of energy to work with by the time it gets there. It would be better for lower-flying targets, though ground clutter could be an issue there for its active sensor.

 

It was primarily designed for an intercept role which would involve attacking lumbering bombers at that range before they could fire their jumbo cruise missiles, and "falling through" them. A more maneuverable aircraft, like say a Mig-25 or 31 probably would not have a lot of trouble escaping if they saw it coming. A 1,000lb missile trying to make high G turns with only inertia and gravity to rely on is going to be a pretty low PK.

 

Don't get me wrong, I was sad to see the Phoenix retired (and the Tomcat too). We are only starting to finally recapture some of the range capability we had when it was in service (AMRAAM AIM-120D), but as far as missiles go, it had to be a bit of a pig at the longer ranges compared to other missiles.

 

We are rather far afield of the topic at this point. I mentioned the Phoenix in the first place while proposing that there might be certain "data" present in the tracking illuminators that allow the missiles to know which target belongs to them, which might be useful by an RWR system. As the F-14 with the AIM-54 has the capability to launch on 6 different target simultaneously it would be a good example assuming it does any SARH tracking at all.

 

I've seen plenty of other posts by you that lead me to believe you know what you're talking about, so I trust whatever you've been able to confirm, but I would still like to know where you get the info. A very interesting discussion either way.

[KingMen1]

I have a question too. So if you're locked by an enemy fighter with AESA radar (e.g. MiG-35) and fires you a SARH missile like R-27ER will you get any warning?

[Shadow KT]

What about aim-7 launches in flood mode? Last time I tested that, there was no missile launch warning for such fired missile in that mode

[GGTharos]

Is the method used to confirm something you can share? I'd definitely like to learn more about its guidance system.

 

I read the parts list and maintenance doc.

 

My assertion of poor terminal maneuvering performance is based on the fact it is gliding by the time it reaches a distant target. For High-flying targets it doesn't have a ton of energy to work with by the time it gets there. It would be better for lower-flying targets, though ground clutter could be an issue there for its active sensor.

 

That is a lot of assumptions.

High-flying aircraft can't really maneuver, and the Phoenix was also intended to destroy cruise missiles. Pretty much most missiles are gliding when they encounter their target at BVR ranges, but that doesn't stop them from keeping a lot of speed and thus maneuvering potential.

As for ground clutter etc, depends on the missile version.

 

As the F-14 with the AIM-54 has the capability to launch on 6 different target simultaneously it would be a good example assuming it does any SARH tracking at all.

 

In TWS modes there is no 'tracking illumination', pretty much by default :) Although the F-14 was required to use STT for bombers at around 90nm or longer, and 50nm or so for fighters IIRC.

[GGTharos]

That is a bug.

 

What about aim-7 launches in flood mode? Last time I tested that, there was no missile launch warning for such fired missile in that mode

[GGTharos]

I'm sure you would. The R-27ER requires a stable waveform to guide on, so you can't be playing LPI tricks.

 

I have a question too. So if you're locked by an enemy fighter with AESA radar (e.g. MiG-35) and fires you a SARH missile like R-27ER will you get any warning?

[KingMen1]

Interesting! Thank you ;)

[fltsimbuff]

I read the parts list and maintenance doc.

 

That is a lot of assumptions.

High-flying aircraft can't really maneuver, and the Phoenix was also intended to destroy cruise missiles. Pretty much most missiles are gliding when they encounter their target at BVR ranges, but that doesn't stop them from keeping a lot of speed and thus maneuvering potential.

As for ground clutter etc, depends on the missile version.

 

 

It wasn't only my assumptions. Nearly every document I've read about the AIM-54 has detailed the same limitation. Most Air-to-Air missiles don't weigh a half ton, which makes a big difference. Poor terminal performance at range against maneuvering targets is pretty much "common knowledge" when it comes to the Phoenix.

 

Soviet "Cruise missiles" of that era were pretty much full fighter-size airframes that flew a mostly straight path to the target at low altitudes and required guidance from a controlling aircraft (imagine a Mig-17 hanging under the bomber's wing and you get the idea).

 

The controlling aircraft would stay at high altitude a long range from the fleet spotting ships with radar and sending radio commands to the cruise missiles. The long range of the Phoenix was intended to take out the bombers before they got in range of their cruise missiles and/or take out the controlling aircraft. The C model had some improvements made to it for better tackling smaller targets but dealing with large #s of large bombers at range was what the Phoenix was originally designed for.

 

If the Phoenix had the technology back in 1966 to take out cruise missiles at long range, modern AMRAAM development would have been redundant. It was designed to counter a very specific threat and used a number of clever tricks to accomplish that goal, although with some well known weaknesses.

 

In TWS modes there is no 'tracking illumination', pretty much by default :) Although the F-14 was required to use STT for bombers at around 90nm or longer, and 50nm or so for fighters IIRC.

 

The AWG-9 Radar tracked in "spotlight mode" where it would shift from each of the 6 targets one at a time, not keeping a constant track on any one target. If the target were able to move a significant amount out of the "spotlight" between intervals the track would be lost.

 

Most pre-AESA TWS radars work in a way similar to this, painting tracks with additional energy, but not a constant beam. Using phased arrays and remembering the track locations they can continue to be "spotlighted" on subsequent scans. As mechanical motion swept the radar cone away from the tracks the phase-change capability of the radar could continue to hit specific areas with an increased amount of energy.

[GGTharos]

It wasn't only my assumptions. Nearly every document I've read about the AIM-54 has detailed the same limitation. Most Air-to-Air missiles don't weigh a half ton, which makes a big difference. Poor terminal performance at range against maneuvering targets is pretty much "common knowledge" when it comes to the Phoenix.

Why does it have 'poor terminal maneuvering'? Is it lack of speed, missile's structural limitation, seeker limitation, or control limitation. So, for simulation this isn't really enough.

 

If the Phoenix had the technology back in 1966 to take out cruise missiles at long range, modern AMRAAM development would have been redundant. It was designed to counter a very specific threat and used a number of clever tricks to accomplish that goal, although with some well known weaknesses.

It wouldn't have been redundant at all. It operates quite differently, better than an AIM-54. It does away with weaknesses in the AIM-54 system. As for the 54 itself, it was upgraded to engage small targets in clutter quite quickly IIRC.

 

Most pre-AESA TWS radars work in a way similar to this

No, they really don't. Not a lot of radar sets use spot-lighting. TWS tracks are a software thing. Spotlighting slows down the scan, and it can trigger an RWR. On the other hand, you can use it to track out of the designated search azimuth/elevation. Pros and cons.

 

Using phased arrays and remembering the track locations they can continue to be "spotlighted" on subsequent scans. As mechanical motion swept the radar cone away from the tracks the phase-change capability of the radar could continue to hit specific areas with an increased amount of energy.

That's sort of how it works, but not quite. TWS always remembers the track locations. There's a reason why it's called a radar track - it's a file in memory. :) AESA radars use SWT which is a different method, though on the surface it will appear to be very similar, and in the end it accomplishes the same thing - just better.

[fltsimbuff]

Why does it have 'poor terminal maneuvering'? Is it lack of speed, missile's structural limitation, seeker limitation, or control limitation. So, for simulation this isn't really enough.

 

It is physics. Objects with more mass have more inertia. Momentum can be helpful to get you to a target in a straight line, but inertia is bad when you need to make a high G turn. The high speed and loads of inertia from sheer mass and speed make it more difficult to maneuver. These are the same laws of physics that have a huge impact on dogfights and every other AAM or SAM. Big and heavy = sluggish turning unless you've got the thrust to maintain energy and some massive control surfaces.

 

It wouldn't have been redundant at all. It operates quite differently, better than an AIM-54. It does away with weaknesses in the AIM-54 system. As for the 54 itself, it was upgraded to engage small targets in clutter quite quickly IIRC.

 

That is pretty much my point. It was great at what it was designed to do (well, in theory), but had major weaknesses. There were trade-offs made so that it could accomplish its core mission (quickly reaching long ranges) that made it not so good at other things (engaging smaller more agile targets at range). The AMRAAM isn't an improved Phoenix, but a missile built to be better all around.

 

No, they really don't. Not a lot of radar sets use spot-lighting. TWS tracks are a software thing. Spotlighting slows down the scan, and it can trigger an RWR. On the other hand, you can use it to track out of the designated search azimuth/elevation. Pros and cons.

 

Spotlighting does not slow down the scan in Phased Array radars. They might decrease the total transmit power available for the scan, but it doesn't slow the scan down. The mechanical scan mechanism does not change speed of traversal. The "steering" is done by Phasing.

 

That's sort of how it works, but not quite. TWS always remembers the track locations. There's a reason why it's called a radar track - it's a file in memory. :) AESA radars use SWT which is a different method, though on the surface it will appear to be very similar, and in the end it accomplishes the same thing - just better.

 

Memory of the track is 1 part of TWS mode. The other half involves allocating additional energy to maintenance of those tracks. A simple track memory is not enough to guide a missile onto a target, but both methods are used together. AESA is Phased Array and then PESA taken to the next level. They implement many more transmitters and eliminate the need for mechanical steering altogether.

 

Interestingly, a similar sort of "Phased Array" technology has now found its way into Wifi routers under the 802.11ac standard in a feature called "beam forming."

[GGTharos]

It is physics. Objects with more mass have more inertia. Momentum can be helpful to get you to a target in a straight line, but inertia is bad when you need to make a high G turn. The high speed and loads of inertia from sheer mass and speed make it more difficult to maneuver. These are the same laws of physics that have a huge impact on dogfights and every other AAM or SAM. Big and heavy = sluggish turning unless you've got the thrust to maintain energy and some massive control surfaces.

 

I think you misunderstand. A missile doesn't care about all that if it's fast in terminal. There's simply no time to divest it of its speed - that's laws of physics, too. That's why you see huge missiles with huge range being fearsome today.

 

That is pretty much my point. It was great at what it was designed to do (well, in theory), but had major weaknesses. There were trade-offs made so that it could accomplish its core mission (quickly reaching long ranges) that made it not so good at other things (engaging smaller more agile targets at range). The AMRAAM isn't an improved Phoenix, but a missile built to be better all around.

I don't want to go in circles, my point is that details are very, very important when it comes to simulation. The 54A/C and AWG-9 were built using the capabilities of the time. At that time, it appears that an M-link wasn't exactly available for a fighter-based radar. It's not like one couldn't be retrofitted, but it appears that this never happened, for reasons unknown.

 

Spotlighting does not slow down the scan in Phased Array radars. They might decrease the total transmit power available for the scan, but it doesn't slow the scan down. The mechanical scan mechanism does not change speed of traversal. The "steering" is done by Phasing.

Anything 'extra' the AESA does will slow it down. It might not seem like it because it's very nicely managed, but it does slow down.

 

Memory of the track is 1 part of TWS mode.

Yep, the other part is the missile uplink with MCUs.

 

The other half involves allocating additional energy to maintenance of those tracks.

No, it does not. It's simply not necessary and may not even be desirable. When it comes to AWG-9 and 54's, requirements may differ.

 

A simple track memory is not enough to guide a missile onto a target, but both methods are used together.

It's quite enough. That's pretty much how every modern fighter does it. Spotlighting is usually commanded either manually or if an STT track is dropped/dropping in order to recover it. It isn't used in the course of maintaining the radar track, or for guidance.

 

Interestingly, a similar sort of "Phased Array" technology has now found its way into Wifi routers under the 802.11ac standard in a feature called "beam forming."

You have your technological dates upside down. Beam forming has been around for-ever. The difference is that the onboard radio chips in the routers can now support multiple simultaneous streams fed through multiple antennae. Antennae can be designed to beam-form, or not. It's not a new thing, and it doesn't resemble what the AESAs/PESAs do. To make that part more clear, you can't 'program' the beam shape. It's set to whatever the antenna design is.

[fltsimbuff]

I think you misunderstand. A missile doesn't care about all that if it's fast in terminal. There's simply no time to divest it of its speed - that's laws of physics, too. That's why you see huge missiles with huge range being fearsome today.

 

Think of a Bus trying to make a tight turn around a corner vs a small rally car going the same speed. The same principles apply. If a target breaks hard during terminal guidance upon seeing the Phoenix's active radar on their RWR, the much faster missile has to make a much higher G turn to catch them. Chaff and other countermeasures also become more effective when you can maneuver. The Phoenix was never built to deal with this, as it was intended to knock out larger aircraft that could not pull high G turns. For this use they were able to build it big and heavy, which allowed the long range. It was a trade-off.

 

I don't want to go in circles, my point is that details are very, very important when it comes to simulation. The 54A/C and AWG-9 were built using the capabilities of the time. At that time, it appears that an M-link wasn't exactly available for a fighter-based radar. It's not like one couldn't be retrofitted, but it appears that this never happened, for reasons unknown.

 

The Phoenix was built with 1960s technology and the AMRAAM with late 1980-90s tech. Sidewinders were designed in the 1950s but have had continual technology refreshes. The Phoenix and the Sidewinder were designed to do very different things. One was a light missile intended for close-in engagements, and were very agile. The other was a very heavy missile intended to reach long distances but sacrificed agility to do it. My point is that the Phoenix wasn't some state-of-the-art ahead of its time weapons system. By the 1960s we could send missiles long distances easily, but it was a trade-off using 1960s technology. The AIM-120 uses much newer technology to allow it to engage targets at range and up close and to do so in a much lighter airframe. This is a result of technological progression. I am not even sure we are disagreeing on this point. Saying that the Phoenix would have no problem with highly agile targets at long distances just doesn't make any sense given the data and what it was designed to do.

 

Anything 'extra' the AESA does will slow it down. It might not seem like it because it's very nicely managed, but it does slow down.

 

I wasn't talking about AESA, but Phased-Array mechanical radars. Even so that is not quite correct. Electronic steering is based on the principal that rather than having 1 ultra-powerful transmitter, you can have multiple transmitters of lower power, and "phase-shift" them so their waves overlap, effectively providing the power of a more powerful transmitter. However, if you don't need the power, you can have some transmitters not directly participating in the scan. This results in an effective loss of power at least part of the time, but doesn't slow it it down.

 

AESA radars are not used in the same way as mechanically steered radars. For example, the APG-77 on the F-22 contains about 2,000 individual transmit/receive modules. All modules can be scanning, giving the system very good range, or you can have some transmitters tracking in other parts of the sky so that the overall scan power is limited, but proceeds with the same speed. These operate in parallel. With advanced AESA radars they can even scan multiple parts of the sky at the same time resulting in a near instantaneous and continuous full-arc scan. As these radars become faster and more powerful, the line between scanning and tracking blurs.

 

It's quite enough. That's pretty much how every modern fighter does it. Spotlighting is usually commanded either manually or if an STT track is dropped/dropping in order to recover it. It isn't used in the course of maintaining the radar track, or for guidance.

 

With command-link guidance, sure. The discussion is about SARH. Remember that the missiles don't have antennas as large as a powerful AESA array and cannot take advantage of the same features for SARH mode. They need a more constant, higher amount of radiation illuminating the target. So even if the launching aircraft doesn't need to illuminate the target in the same way, a SARH missile still needs the track illuminated with enough power to pick up.

 

You have your technological dates upside down. Beam forming has been around for-ever. The difference is that the onboard radio chips in the routers can now support multiple simultaneous streams fed through multiple antennae. Antennae can be designed to beam-form, or not. It's not a new thing, and it doesn't resemble what the AESAs/PESAs do. To make that part more clear, you can't 'program' the beam shape. It's set to whatever the antenna design is.

 

Beam forming is not actually changing beam shape at all. It is electronic beam steering based on altering the RF phase. It is just called "beam forming" in Wifi routers. The idea behind phased arrays, "beam forming" and AESA all boil down to using multiple transmitters with phases that overlap at certain spatial locations. For example, if a signal is received at 2 antennas, the device can calculate the phase shift between the 2 signals and accordingly shift its transmit phase from the 2 transmitters such that when both signals reach the target, the effective power is increased from the amplitudes overlapping precisely.

 

The phase shift necessary for the 2 separate signals to combine into a stronger single signal depends on the azimuth and range of the target. At other spatial locations the signal will be weaker overall as the phases of the 2 signals will be offset. This can be used for receipt of signals as well, where the receiving antennas shift the phase such that signals arriving from a single spatial location will overlap in the signals monitored by the 2 separate receivers.

 

Now increase from 2 transmitter/receivers to the 2,000 in a modern AESA array and you've got one awesome phase-shifting array that can phase-shift to cover any point within a 120 degree arc without any mechanical antenna aiming at all. Now take 200 of those and phase-shift them to cover 1 spot in the sky continuously and you can track while the other 1800 keep scanning at the same speed but without the extra power from the 200 that are occupied.

 

There are definitely other ways to use that array that probably make my explanation sound silly and oversimplified, but the base concept starts there with MANY possibilities only limited by the software.

[GGTharos]

Think of a Bus trying to make a tight turn around a corner vs a small rally car going the same speed. The same principles apply. If a target breaks hard during terminal guidance upon seeing the Phoenix's active radar on their RWR, the much faster missile has to make a much higher G turn to catch them. Chaff and other countermeasures also become more effective when you can maneuver. The Phoenix was never built to deal with this, as it was intended to knock out larger aircraft that could not pull high G turns. For this use they were able to build it big and heavy, which allowed the long range. It was a trade-off.

 

Please, no car analogies. Really, I actually know what I'm talking about, because I've done the research and I have done the actual math. So again, the question becomes this:

 

Is the lack of terminal capability structural (can't take the g's), control (can't generate the g's) or seeker (can't track under g's)?

 

It doesn't matter that the missile weighs 600lbs after fuel burn-out, it could be build to satisfy all of the above, or not. It's really not a bus and car thing. There exist huge modern missiles heavier than Phoenix that do just fine with all this.

 

The Phoenix was built with 1960s technology and the AMRAAM with late 1980-90s tech. Sidewinders were designed in the 1950s but have had continual technology refreshes. ... [snip] ... Saying that the Phoenix would have no problem with highly agile targets at long distances just doesn't make any sense given the data and what it was designed to do.

 

Do you have your hands on the design or requirement documents? I don't, but if you do, I'd love to see it. Otherwise this is all just hearsay.

 

I wasn't talking about AESA, but Phased-Array mechanical radars. Even so that is not quite correct. [snip] This results in an effective loss of power at least part of the time, but doesn't slow it it down.

 

Not only are you telling me things I know, you're actually wrong. Yes, an AESA/PESA or combined M(PA)ESA will slow down its scan given certain circumstances.

 

With advanced AESA radars they can even scan multiple parts of the sky at the same time resulting in a near instantaneous and continuous full-arc scan. As these radars become faster and more powerful, the line between scanning and tracking blurs.

 

No, they actually can't, or more to the point, they don't split use of the array, as that distorts the signal in ways that are detrimental. You form a beam in one direction, not two or more.

 

With command-link guidance, sure. The discussion is about SARH. Remember that the missiles don't have antennas as large as a powerful AESA array and cannot take advantage of the same features for SARH mode. They need a more constant, higher amount of radiation illuminating the target. So even if the launching aircraft doesn't need to illuminate the target in the same way, a SARH missile still needs the track illuminated with enough power to pick up.

 

Which is why you guide with with an M-link until it gets close enough to see the reflected signal. Plenty of SARH missiles do that.

 

Beam forming is not actually changing beam shape at all.

 

Oh yes it is.

 

It is electronic beam steering based on altering the RF phase. It is just called "beam forming" in Wifi routers.

 

I thought you were talking about something else, but that was new for me, for routers - so I looked it up. Doesn't really resemble what a PESA/AESA does though, except in the most general sense of steering the radiation pattern.

 

Now take 200 of those and phase-shift them to cover 1 spot in the sky continuously and you can track while the other 1800 keep scanning at the same speed but without the extra power from the 200 that are occupied.

 

Now you're making stuff up. The entire array steers together. Anything else is very inefficient. The concept used here is dwell time - how much power and time (ie. pulses) do you need to detect or track something, or to gain certain information? That's why ESA radars are described in technical literature as being able to form 1000/2000/3000 beams/sec. You can consider the beam to have one size (not necessarily true, but also not relevant here), and then you need to figure out how many beams you need to fill out your scan volume.

 

So if given the parameters:

- 120x120 scan volume (the array's entire field of regard)

- 1.5 deg diameter beam

- 2800 beams/sec

 

You'd scan the entire volume in a little over 3 sec if everything filled in neatly, a little more if you wanted beam overlap.

 

There are definitely other ways to use that array that probably make my explanation sound silly and oversimplified, but the base concept starts there with MANY possibilities only limited by the software.

 

There are plenty of very real physical limitations. These things are far better and faster, and smarter than MSAs, but they're not quite what you're trying them out to be. Refer to laws of physics you mentioned earlier. Oe perhaps laws of engineering or gremlins - either way, splitting the array would be a very special case and not normal operation to the best of my knowledge. It's just a bad deal in terms of computing, not to mention mutual interference.

[fltsimbuff]

Is the lack of terminal capability structural (can't take the g's), control (can't generate the g's) or seeker (can't track under g's)?

 

It doesn't matter that the missile weighs 600lbs after fuel burn-out, it could be build to satisfy all of the above, or not. It's really not a bus and car thing. There exist huge modern missiles heavier than Phoenix that do just fine with all this.

 

You seem to be presuming those are the only things that factor. Energy going into a high G turn matters, and affects how long you can maintain that high G turn as well as how much speed or energy you have coming out of it. In the case of the missile, the additional weight matters because it will burn more energy in the same turn than a lighter missile. And the thrust at this point is 0, so that is energy/speed it cannot get back. A high mass missile with 0 thrust will run out of energy faster than an F-15 turning and burning.

 

Without having access to actual data about the maneuvering of an AIM-54 at 100nm against a target in a 9G turn there's not much point in arguing about it. But I think we can both agree that an AIM-9 with its motor still burning or an AIM-54 at 40nm would fare far better against the same target?

 

Do you have your hands on the design or requirement documents? I don't, but if you do, I'd love to see it. Otherwise this is all just hearsay.

 

This is actually well-known. Look at the threats present at the time the Missileer project was started, and the role of "Fleet Interceptor" that was what became the F-14/Phoenix. Many many documents exist out there stating that the Fleet Interceptor role was to combat large numbers of bombers with their cruise missiles. This was the concern of the Navy at the time that the missile and the fighter were designed. The AWG-9 could track and fire on 6 targets at one time to meet the expected threat of a high threat density.

 

Note in a retirement announcement from the NAVY itself they talk specifically of the targets the Phoenix was intended to combat, aircraft such as the Tu-22 and Tu-16.

http://www.navy.mil/submit/display.asp?story_id=15422

 

No, they actually can't, or more to the point, they don't split use of the array, as that distorts the signal in ways that are detrimental. You form a beam in one direction, not two or more.

 

Lots of sources talking about AESA radars out there disagree with you and indicate multiple distinct beams can be and are formed with modern AESA radars.

 

Which is why you guide with with an M-link until it gets close enough to see the reflected signal. Plenty of SARH missiles do that.

 

On missiles that use such a link. Again, I am talking about SARH missiles, which many of the early ones required a lock on for their own seekers before they left the rails. LOAL (Lock On After Launch) mode was a later advancement.

 

Oh yes it is.

 

I thought you were talking about something else, but that was new for me, for routers - so I looked it up. Doesn't really resemble what a PESA/AESA does though, except in the most general sense of steering the radiation pattern.

 

Like I said. They call it "beam forming" but it is really electronic steering. It is very primitive but uses the same phase-shifting principles.

 

Now you're making stuff up. The entire array steers together. Anything else is very inefficient. The concept used here is dwell time - how much power and time (ie. pulses) do you need to detect or track something, or to gain certain information? That's why ESA radars are described in technical literature as being able to form 1000/2000/3000 beams/sec. You can consider the beam to have one size (not necessarily true, but also not relevant here), and then you need to figure out how many beams you need to fill out your scan volume.

 

So if given the parameters:

- 120x120 scan volume (the array's entire field of regard)

- 1.5 deg diameter beam

- 2800 beams/sec

 

You'd scan the entire volume in a little over 3 sec if everything filled in neatly, a little more if you wanted beam overlap.

 

Again, what you're saying doesn't jive with the available information. It is possible all available information is false and you're getting your information from an authoritative source, but I don't see anything so far that would convince me of that. AESA radars can and do form multiple logical "beams" for speedier coverage of scan area. It is possible that these are time-division scans rather than simultaneous as it doesn't usually specify, but some of the language implies concurrent.

 

http://www.globalsecurity.org/military/systems/aircraft/systems/an-apg-77.htm

http://en.wikipedia.org/wiki/Active_electronically_scanned_array

 

There are plenty of very real physical limitations. These things are far better and faster, and smarter than MSAs, but they're not quite what you're trying them out to be. Refer to laws of physics you mentioned earlier. Oe perhaps laws of engineering or gremlins - either way, splitting the array would be a very special case and not normal operation to the best of my knowledge. It's just a bad deal in terms of computing, not to mention mutual interference.

 

Okay that might have had a little too much hyperbole, but the point I was trying to make was that my explanation of Electronically Steered Arrays was an oversimplified one meant to get across the basic idea of electronic steering, and that there are many ways the inherent advantages can be used for things like SAR, communications, jam resistance, etc. I thought it was obvious I didn't mean that AESA would enable time travel or faster than light warp drives, but by moving most of the functionality into software there are many many things that can be done that you cannot with a standard radar.

[GGTharos]

You seem to be presuming those are the only things that factor. Energy going into a high G turn matters, and affects how long you can maintain that high G turn as well as how much speed or energy you have coming out of it. In the case of the missile, the additional weight matters because it will burn more energy in the same turn than a lighter missile. And the thrust at this point is 0, so that is energy/speed it cannot get back. A high mass missile with 0 thrust will run out of energy faster than an F-15 turning and burning.

 

Did you know that there are some really heavy jets out there than glide better than the much lighter F-15? That works for turns, too.

 

Without having access to actual data about the maneuvering of an AIM-54 at 100nm against a target in a 9G turn there's not much point in arguing about it. But I think we can both agree that an AIM-9 with its motor still burning or an AIM-54 at 40nm would fare far better against the same target?

 

We know how to simulate any of those conditions, don't really need the classified data - what's needed is the system specification, which is also sadly classified (or at least it appears to be). Then we can do a proper simulation as least.

 

This is actually well-known.

 

No, in fact it is not known at all because the design and requirements documents are not available. Also it is not know what exactly the updates did, other than a general description. I don't care how many wikipedia pages or pilots you quote, those usually tell you nothing - worse, they mislead you.

 

On missiles that use such a link. Again, I am talking about SARH missiles, which many of the early ones required a lock on for their own seekers before they left the rails. LOAL (Lock On After Launch) mode was a later advancement.

 

That isn't news, and I don't see any relevance. SARH missiles (or any missiles) can use an M-Link of any type (command, MCU, beam, whatever) or not. It's a design choice based on available technology. If you don't use any of this, your missile instantly becomes that much more prone to spoofing.

 

Again, what you're saying doesn't jive with the available information. It is possible all available information is false and you're getting your information from an authoritative source, but I don't see anything so far that would convince me of that. AESA radars can and do form multiple logical "beams" for speedier coverage of scan area. It is possible that these are time-division scans rather than simultaneous as it doesn't usually specify, but some of the language implies concurrent.

 

You're misunderstanding what they mean by multiple beams, or the articles are misrepresenting things because the authors also don't understand the subject matter.

 

Simultaneous beams isn't an impossible thing, it's merely (very) impractical. No one that I know of splits the array in practical applications - it's flat out prohibitive. The computing requirements grow exponentially, you lose power doing it, you start introducing sidelobes and EMI, it's generally undesirable and there's simply no need for it whatsoever; if you're forming 2800 beams a second, you can use 100-200 for most of your track updates. You can use fewer too if a track is low priority and especially if it is far away, since it's more likely to just fall inside a single beam for the track update - or you can simply update them during the scan cycle instead of a 're-visit'. These are all choices for resource management, they're all valid, they all have pros and cons.

 

Okay that might have had a little too much hyperbole, but the point I was trying to make was that my explanation of Electronically Steered Arrays was an oversimplified one meant to get across the basic idea of electronic steering, and that there are many ways the inherent advantages can be used for things like SAR, communications, jam resistance, etc. I thought it was obvious I didn't mean that AESA would enable time travel or faster than light warp drives, but by moving most of the functionality into software there are many many things that can be done that you cannot with a standard radar.

 

I've forgotten more about these systems than I know right now, and I don't really know all that much. I'll leave it at that.

[fltsimbuff]

Did you know that there are some really heavy jets out there than glide better than the much lighter F-15? That works for turns, too.

 

We know how to simulate any of those conditions, don't really need the classified data - what's needed is the system specification, which is also sadly classified (or at least it appears to be). Then we can do a proper simulation as least.

 

No, in fact it is not known at all because the design and requirements documents are not available. Also it is not know what exactly the updates did, other than a general description. I don't care how many wikipedia pages or pilots you quote, those usually tell you nothing - worse, they mislead you.

 

I've read this many times over the years. Gaining any knowledge of history and how the cold war developed will tell you this. The Cold War was a series of actions and reactions. Defensive weapons are deployed against the current or predicted threat. Looking at the threats faced by our carrier groups makes this rather obvious, but don't take my word for it...

 

http://arc.aiaa.org/doi/abs/10.2514/6.2011-7027

"A long-range missile, the AIM-54 was intended to be used against slow, non-maneuvering enemy targets such as bombers and strike aircraft that were intent on attacking US carrier battle groups"

 

Not only does it make perfect sense given the threats of the time, but I have seen similar things said many times over the years. In addition, nearly every document I have seen talking about the 'C' upgrade lists "improved effectiveness against cruise missiles and tactical aircraft" as a major feature. Tactical aircraft would be the smaller maneuvering targets and not the larger "strategic" bombers. The AIM-54A was designed for intercept of strategic bombers attacking the fleet with cruise missiles. A little historical context goes a long way to understanding the design.

 

While the 'C' model may have added some increased effectiveness to the guidance of the missile for tactical aircraft, it was still a half-ton glider with proportionally tiny control surfaces when it reached the target. With an increase in mass, the forces used to maneuver must also be increased. This means larger control surfaces and lift area. The Phoenix had better lift surfaces than some missiles, but control surfaces were necessarily small. Gliding in a straight line and turning are very different things. The latter relies on control surfaces being larger to generate more differential force. That additional force comes at the expense of energy.

 

That isn't news, and I don't see any relevance. SARH missiles (or any missiles) can use an M-Link of any type (command, MCU, beam, whatever) or not. It's a design choice based on available technology. If you don't use any of this, your missile instantly becomes that much more prone to spoofing.

 

I am not exactly sure why the command links keep coming up. I am still talking about SARH, not command-link. While they are not mutually exclusive, many SARH missiles did not have command link. In all my additional reading on the AIM-54C in locating the links above, I am even more certain the AIM-54 had no such link and used SARH. If it did, it's still classified information or no one has bothered to share it.

 

You're misunderstanding what they mean by multiple beams, or the articles are misrepresenting things because the authors also don't understand the subject matter.

 

Simultaneous beams isn't an impossible thing, it's merely (very) impractical. No one that I know of splits the array in practical applications - it's flat out prohibitive. The computing requirements grow exponentially, you lose power doing it, you start introducing sidelobes and EMI, it's generally undesirable and there's simply no need for it whatsoever; if you're forming 2800 beams a second, you can use 100-200 for most of your track updates. You can use fewer too if a track is low priority and especially if it is far away, since it's more likely to just fall inside a single beam for the track update - or you can simply update them during the scan cycle instead of a 're-visit'. These are all choices for resource management, they're all valid, they all have pros and cons.

 

I've forgotten more about these systems than I know right now, and I don't really know all that much. I'll leave it at that.

 

These aren't really "beams" at all. That's more of a concept to describe the way the RF is being used and "focused" electronically. Sidelobes and EMI are a fact of life for radio transmitters. With the ability for each transmitter to operate on its own frequency that will help a bit with the interference. With all of the different things AESA is going to be used for (we hear about increased capabilities every day) the ability to have concurrent spatial "focusing" of multiple "beams" could very well be a useful feature, even with some power loss.

 

I agree there's a lot of bad information out there. No offense intended, but I usually lean toward the consensus of available information and not information provided by one person of unknown credentials using unknown sources. I consider these capabilities as "possible, but unverified" as with most things that are mostly classified. Below are some specific articles, some straight from the AESA manufacturers that state multiple-simultaneous-beam forming capabilities. I suppose Raytheon, Northrop Grumman, and Lockheed Martin could all be lying about functionality, but I somehow doubt it.

 

-From a presentation by a Lockheed Martin Engineer: http://www.ofcm.gov/mpar-symposium/2009/presentations/workshop/W2_Al-Rashid%20Architecture.pdf

-- "Digital beamforming affords multiple simultaneous beams.."

-- Diagram on page 15 showing example of multiple simultaneous beams increasing scan speed.

 

-Another article, and regarding one of Northrop Grumman's offerings: http://mwrf.com/analog-devices/radar-systems-ride-device-advances

-- "Because system performance can be quickly redefined, the HAMMR system can readily adapt to new threats without additional hardware. Also, groups of modules can be dedicated to different targets, allowing them to be tracked simultaneously." (emphasis mine)

 

-An article by Raytheon about their AESA radar tech: http://www.raytheon.com/news/technology_today/2014_i1/aesa.html

-- "This will enable unprecedented performance and new capabilities for radar, communications and EW missions such as creating and processing multiple simultaneous beams, increased polarization diversity and improved dynamic range." (emphasis mine)

 

-An article by another RF systems manufacturer about the tech: http://www.altera.com/technology/system-design/articles/2013/scanned-radar-signal-processing.html

-- "This approach, aside from eliminating a lot of big moving parts, allows the radar to do things that are physically impossible with a conventional antenna, such as changing the beam direction instantaneously, having multiple antenna patterns for transmitting and receiving simultaneously, or even subdividing the array into multiple antenna arrays and performing multiple functions—say, searching for targets, tracking a target, and following terrain—simultaneously." (emphasis mine)

 

- Another article about AESA systems in general: http://www.satellite-evolution.com/issues-2011/gmc-oct-2011/radar.pdf

-- "AESA antennas comprise hundreds or even thousands of transmit/receive modules and each of these modules acts as an individual radar. It truly is a case of strength in numbers. The AESA is solid state – there are no moving parts, and this increases the overall reliability of the system as there are basically less things that can go wrong. An AESA radar can steer its beams electronically – nearly at the speed of light – and can re-direct them instantly from one target to another making them extremely versatile and agile. The modules can work together or in groups enabling them to perform multiple tasks at the same time." (emphasis mine)

Edited January 12, 2015 by fltsimbuff
Added citations

[GGTharos]

A little historical context goes a long way to understanding the design.

 

It goes a long way towards assuming that you understand something about the design, and that's all it is. Without the specs, you won't really know. There are plenty of weapons out there that can surprise you with capability they were never designed for (... and vice versa too, of course :P )

 

While the 'C' model may have added some increased effectiveness to the guidance of the missile for tactical aircraft, it was still a half-ton glider with proportionally tiny control surfaces when it reached the target. With an increase in mass, the forces used to maneuver must also be increased. This means larger control surfaces and lift area. The Phoenix had better lift surfaces than some missiles, but control surfaces were necessarily small. Gliding in a straight line and turning are very different things. The latter relies on control surfaces being larger to generate more differential force. That additional force comes at the expense of energy.

I really mean tit when I said I did the math. Please quit throwing generalities at me and actually show me that it can't do it aerodynamically, as compared to another missile.

 

You're quite a bit off the mark here. The Phoenix's control surfaces are quite large, and its strakes provide a lot of lift. Aerodynamically speaking, there's no problem with it making high-g maneuvers, nor is loss of energy in a turn a particularly big problem for the phoenix compared to other missiles - they all pay the price, and there are plenty of algorithms out there that try to preserve energy in various phases of flight.

 

So again, that leaves the 'terminal maneuvering' question un-answered (and what does terminal maneuvering mean anyway? The fact is it means that the end result is a large miss distance):

 

- Is it because of seeker limitations? (poor seeker motive power, excessive settling time, etc)

- Is it because of structural limitations? (If the missile can 'only' pull up to 18g, then it's limited to a 6g target at high speeds, very, veeeery generally speaking)

- Is it because there is not adequate motive power for the control surfaces to pull more g?

 

 

While the missile could arrive at low speed, I've seen AIM-54 shot profiles that would let it keep M2 at intercept at insane ranges, so I'm not even asking the speed question.

 

'Poor terminal maneuvering' here isn't just about max range, because at max range, well - duh - you probably have low speed.

 

 

I am not exactly sure why the command links keep coming up. I am still talking about SARH, not command-link. While they are not mutually exclusive, many SARH missiles did not have command link. In all my additional reading on the AIM-54C in locating the links above, I am even more certain the AIM-54 had no such link and used SARH. If it did, it's still classified information or no one has bothered to share it.

Because the lack of a data-link (not same as command-link, they do different things) or command-link really makes me wonder about the system design. I certainly agree that it appears not to mentioned anywhere, and all the literature so far says that the missile used SARH-to-ARH guidance. This makes it incredibly vulnerable to certain things that would negate its range.

 

These aren't really "beams" at all. That's more of a concept to describe the way the RF is being used and "focused" electronically.

They fall into the definition of an RF beam, so how are they not beams? Sequential forming of a beam is generating multiple beams. There's a reason why they describe it this way, and the reason is that this is how the software handles things: It generates a beam in a certain direction, and it can generate some amount of those beams every second. If you 'stick' a beam to a target, you can still count it as forming multiple beams for the purpose of assigning resources. Ie. if what you're doing with this beam takes the same amount of time as forming 100 beams, then you count it as 100 beams - that's how many you just took out of your resources.

 

Sidelobes and EMI are a fact of life for radio transmitters.

And getting rid of them is a fact of life for radar design/engineering.

 

With the ability for each transmitter to operate on its own frequency that will help a bit with the interference. With all of the different things AESA is going to be used for (we hear about increased capabilities every day) the ability to have concurrent spatial "focusing" of multiple "beams" could very well be a useful feature, even with some power loss.

You're just hand-waving stuff. I've never heard of any arrays being used that way, for the reasons I mentioned. There is no advantage to it at all.

 

I agree there's a lot of bad information out there. No offense intended, but I usually lean toward the consensus of available information and not information provided by one person of unknown credentials using unknown sources. I consider these capabilities as "possible, but unverified" as with most things that are mostly classified.

No offense intended, but I didn't exactly find that information in thin air. I spoke with RF engineers, pilots, operators, I've read the actual engineering books (not that I'm an RF engineer or anything), read the manuals for real radars as well as maintenance (specifically testing) manuals. This stuff is out there, but not necessarily easy to find or free. If all you're going to do is quote wikipedia and point at the occasional AIAA abstract, then combine it all into your own assumptions, I suggest that you're part of the 'bad information out there', though at least nowhere near as bad as some others. The trick is to keep asking questions, and you're not. Consensus on the internet regarding military technology is ... LOL. At best.

 

It's fine if you don't want to believe me, in the end it makes no difference.

[fltsimbuff]

It goes a long way towards assuming that you understand something about the design, and that's all it is. Without the specs, you won't really know. There are plenty of weapons out there that can surprise you with capability they were never designed for (... and vice versa too, of course :P )

 

I really mean tit when I said I did the math. Please quit throwing generalities at me and actually show me that it can't do it aerodynamically, as compared to another missile.

 

You're quite a bit off the mark here. The Phoenix's control surfaces are quite large, and its strakes provide a lot of lift. Aerodynamically speaking, there's no problem with it making high-g maneuvers, nor is loss of energy in a turn a particularly big problem for the phoenix compared to other missiles - they all pay the price, and there are plenty of algorithms out there that try to preserve energy in various phases of flight.

 

So again, that leaves the 'terminal maneuvering' question un-answered (and what does terminal maneuvering mean anyway? The fact is it means that the end result is a large miss distance):

 

- Is it because of seeker limitations? (poor seeker motive power, excessive settling time, etc)

- Is it because of structural limitations? (If the missile can 'only' pull up to 18g, then it's limited to a 6g target at high speeds, very, veeeery generally speaking)

- Is it because there is not adequate motive power for the control surfaces to pull more g?

 

 

While the missile could arrive at low speed, I've seen AIM-54 shot profiles that would let it keep M2 at intercept at insane ranges, so I'm not even asking the speed question.

 

'Poor terminal maneuvering' here isn't just about max range, because at max range, well - duh - you probably have low speed.

 

And here we go... The main purpose of the Phoenix being long-range intercept, maneuvering at the outer range envelope matters. It was "good enough" for aircraft that also can't maneuver very well and there was the real value against the target for which it was intended. Other missiles do indeed have trouble at the edge of their range envelope as well, and as a result it is a general rule you will close more distance before firing to get the aircraft into the "no-escape zone" depending on target type.

 

But the Phoenix was a bomber interceptor, intended to be fired at edge of envelope at distant bombers. It, as with any missile at the edge of its envelope, would be far less useful against maneuverable targets at the same distance!

 

They fall into the definition of an RF beam, so how are they not beams? Sequential forming of a beam is generating multiple beams. There's a reason why they describe it this way, and the reason is that this is how the software handles things: It generates a beam in a certain direction, and it can generate some amount of those beams every second. If you 'stick' a beam to a target, you can still count it as forming multiple beams for the purpose of assigning resources. Ie. if what you're doing with this beam takes the same amount of time as forming 100 beams, then you count it as 100 beams - that's how many you just took out of your resources.

 

My point was that it is a logical concept, not a "beam" in the traditional sense. Each individual T/R module is going to radiate like any other antenna, not in a specific constrained direction. The sum total forms an imaginary logical "beam." I am only pointing that out because it makes the whole conversation of what constitutes a "separate beam" a lot more complicated.

 

You're just hand-waving stuff. I've never heard of any arrays being used that way, for the reasons I mentioned. There is no advantage to it at all.

 

See my edit to my post above. Plenty of examples, including from engineers and manufacturers.

 

No offense intended, but I didn't exactly find that information in thin air. I spoke with RF engineers, pilots, operators, I've read the actual engineering books (not that I'm an RF engineer or anything), read the manuals for real radars as well as maintenance (specifically testing) manuals. This stuff is out there, but not necessarily easy to find or free. If all you're going to do is quote wikipedia and point at the occasional AIAA abstract, then combine it all into your own assumptions, I suggest that you're part of the 'bad information out there', though at least nowhere near as bad as some others. The trick is to keep asking questions, and you're not. Consensus on the internet regarding military technology is ... LOL. At best.

 

It's fine if you don't want to believe me, in the end it makes no difference.

 

I agree on continuing to ask questions. My point is that when you get multiple answers in conflict, you have to weigh them. You may well have done a ton of research of far more credible sources than I have, but I can take your word for it or I can take the word of multiple engineers and AESA manufacturers. If and when I get additional information to the contrary I will re-evaluate.

 

It's nothing against you, but one intelligent person vs numerous others saying something different is not so complicated.

[GGTharos]

And here we go... The main purpose of the Phoenix being long-range intercept, maneuvering at the outer range envelope matters. It was "good enough" for aircraft that also can't maneuver very well and there was the real value against the target for which it was intended. Other missiles do indeed have trouble at the edge of their range envelope as well, and as a result it is a general rule you will close more distance before firing to get the aircraft into the "no-escape zone" depending on target type.

 

But the Phoenix was a bomber interceptor, intended to be fired at edge of envelope at distant bombers. It, as with any missile at the edge of its envelope, would be far less useful against maneuverable targets at the same distance!

 

Wow, this is frustrating. Am I explaining things wrong?

 

If it goes terminal with that speed, energy is not a problem. And as I've pointed out before, I have seen shot profiles that allow the missile to have such speed out to ranges that will make your eyes bleed (Whether those profiles are realistic or practical is another question)

 

So once more, all this hand-waving does not answer the technical question.

 

So I'll repeat, emphasis mine: Energy is not necessarily the problem, and claiming 'poor terminal maneuverability' raises questions since the missile can be used well within a high-energy envelope, and that envelope can extend quite far.

 

My point was that it is a logical concept, not a "beam" in the traditional sense.

 

It is a beam in the traditional sense. You can measure it in the traditional sense and it works because it is a beam in the traditional sense. Just because it is ...

 

Each individual T/R module is going to radiate like any other antenna, not in a specific constrained direction. The sum total forms an imaginary logical "beam." I am only pointing that out because it makes the whole conversation of what constitutes a "separate beam" a lot more complicated.

 

... formed by multiple TR modules, does not make it 'not a beam in the traditional sense'.

 

See my edit to my post above. Plenty of examples, including from engineers and manufacturers.

Fair enough. I'll believe it when I see it demonstrated and actually used in practice :)

 

I agree on continuing to ask questions. My point is that when you get multiple answers in conflict, you have to weigh them. You may well have done a ton of research of far more credible sources than I have, but I can take your word for it or I can take the word of multiple engineers and AESA manufacturers. If and when I get additional information to the contrary I will re-evaluate.

 

It's nothing against you, but one intelligent person vs numerous others saying something different is not so complicated.

Like I said, you don't have to believe me, I take no offense to that. Edited January 12, 2015 by GGTharos

[fltsimbuff]

Wow, this is frustrating. Am I explaining things wrong?

 

If it goes terminal with that speed, energy is not a problem. And as I've pointed out before, I have seen shot profiles that allow the missile to have such speed out to ranges that will make your eyes bleed (Whether those profiles are realistic or practical is another question)

 

So once more, all this hand-waving does not answer the technical question.

 

So I'll repeat, emphasis mine: Energy is not necessarily the problem, and claiming 'poor terminal maneuverability' raises questions since the missile can be used well within a high-energy envelope, and that envelope can extend quite far.

 

My original comment on "poor terminal maneuverability" was regarding its use as it was intended at the edge of its engagement range. It was built to do a very specific job, as anyone familiar with Soviet vs Western military doctrine and capabilities at the time can tell you.

 

Yes, I fully understand that missiles have much better chances of taking maneuvering targets when they are well within this envelope. You can engage a smaller target at ranges still outside what an AIM-7 can handle and have good performance against it.

 

But whether you believe me or not on the original purpose of the missile (engaging large targets at the edge of its max engagement range) you simply cannot successfully engage a target that near the edge if it is capable of maneuvering out of the envelope. This could be an altitude envelope (remember lofting missiles trade altitude for range at the edge) or range (turn tail and afterburn!) or exceed the maneuverability of the missile near the edge of its envelope.

 

You can sum up my point of view on this as follows (100+nm range is standing in for actual, as actual max range is still unknown):

Was the Phoenix an awesome missile able to engage bombers at 100+nm? Yep!

Was the Phoenix a fighter killer at 100+nm? No.

Does that mean I think it was a failure? Absolutely not. It did what it was supposed to do.

 

I really don't think we're ever going to agree on this. You say you've done math that can tell you what is still classified, that's great. I am not convinced. Maybe we'll see an well-modeled simulation someday that can accurately represent it.

 

It is a beam in the traditional sense. You can measure it in the traditional sense and it works because it is a beam in the traditional sense. Just because it is ...

 

... formed by multiple TR modules, does not make it 'not a beam in the traditional sense'.

 

I concede that you can call it a "beam in the traditional sense" as long as you are looking at the phase shifting as a form of focusing of the energy like a lens does for light. The methods used are dissimilar though.

[GGTharos]

You can sum up my point of view on this as follows (100+nm range is standing in for actual, as actual max range is still unknown):

Was the Phoenix an awesome missile able to engage bombers at 100+nm? Yep!

Was the Phoenix a fighter killer at 100+nm? No.

Does that mean I think it was a failure? Absolutely not. It did what it was supposed to do.

 

You seem stuck on launching this at the edge of its envelope. Not only is this not really done in practice, but you need to examine why and what's going on here:

 

First, what's the edge of the envelope defined by?

 

- Take the Sparrow. It can't be shot at a fighter outside of its envelope unless you're at very low altitude. It's kinematic capability actually out-ranges it's seeker's ability to track a particular RCS as medium and high altitudes.

 

- Take a heat seeker. It's forward envelope is far, far shorter than it's kinematic capability, against because of the seeker.

 

- Take an R-27ER. It's edge of envelope is defined by available working time, it's kinematics far exceed the range at which it'll run out of power to actuate the control surfaces.

 

So now back to the Phoenix. As I pointed out, it can be coming down with M2 speed at terminal, pretty much at almost any range you shoot it at. That means it has plenty of energy to deal with any maneuvers.

 

So, now what defines its 'edge of the envelope'? It's probably not so much about energy. This missile is likely to easily out-range the AWG-9's ability to detect a fighter, and it's own ability to track a fighter, so for the sake of the argument you'll never encounter a fighter in a 'low energy' shot as far as the missile is concerned. Yes, the fighter can turn and run as soon as he knows a missile is coming - if he does it when the missile is launched, then we're talking about the fighter getting out before Rtr, which isn't a 'poor terminal maneuvering' situation, it's flat out missile can't reach it situation. If he turns to run when he gets a warning from the missile itself thought, it's too late. The missile will over-take him.

 

Where does 'poor terminal maneuvering' come from now?

 

I really don't think we're ever going to agree on this. You say you've done math that can tell you what is still classified, that's great. I am not convinced. Maybe we'll see an well-modeled simulation someday that can accurately represent it.

It's relatively easy to do the math. You can do it yourself. In fact, DCS models it quite well if you get the right parameters in there.

 

The dirty secret is that once you have a drag curve and the missile's rocket motor details, you can compute it's worst case performance (not best, since we can't affect the guidance to conserve speed, and we have to artificially fix the glide-angle at each range/closure combination to make it optimal for the purposes of the simulation).

 

In other words, the dirty secret is that no matter how classified the missile is, you can compute it's kinematics as long as you can get those parameters. Parameters for the rocket motor can be gathered from declassified documents. The drag curve can be (educated) guessed at or computed via CFD.

Edited January 13, 2015 by GGTharos

[fltsimbuff]

I am stuck on edge of envelope because that is what mattered for what this missile was designed to do. It was a direct response to the threat of large numbers of Soviet bombers closing on the fleet and attempting to get in range of their supersonic cruise missiles. The Eagle became Falcon, then became Phoenix. All 3 were designed to extend the standoff range against the bombers. The bombers would not turn and run until they fired their payloads, so they didn't need to deal with the targets escaping the envelope. The scenario these missiles were meant to counter was a large group of large aircraft approaching the fleet. This is also why the Tomcat needed to be able to patrol longer and further distances, and have a more powerful radar.

 

The Soviet Union had a lot of nuclear-tipped cruise missiles, so engaging these bombers as far away from the fleet as possible was critical, and given that all the bombers could do is continue to close into their launch range, firing at the edge of the envelope makes sense.

 

The same applies for firing at cruise missiles. They may be far faster and smaller than the bombers, but they would be moving further into the envelope toward the launching platform (and the fleet behind them).

 

The one Phoenix missile that was successfully fired at an Iraqi Mig (23 or 25) missed when the Mig turned tail and ran for it. Iran claims some successful intercepts, but not a lot is known about those (and Iran claims a lot of things).

 

This is not to say that there weren't other considerations during design, but these were biased heavily towards an emphasis on hitting large numbers of bombers from range (early design versions had provisions for carrying a nuclear warhead in fact).

 

I've not only read this numerous times, and seen it in numerous documentaries, but all the known threats of the period and the Navy's doctrine at the time support this.

 

"Poor terminal maneuvering characteristics" was in the context of engagement at its max range, and in part due to the ballistic trajectory.

 

Compared to an AIM-9 against a fast, small and highly maneuverable target, yes, the maneuvering characteristics can be considered poor even closer in.

[GGTharos]

I am stuck on edge of envelope because that is what mattered for what this missile was designed to do. It was a direct response to the threat of large numbers of Soviet bombers closing on the fleet and attempting to get in range of their supersonic cruise missiles.

 

Your assumption isn't correct. If you engage bombers or cruise missiles at very long ranges, you MUST use STT. This immediately negates launching on multiple platforms. This means that any TWS launch, be it against a bomber or a fighter, is quite likely to be well within kinematic capability.

 

Not only that, but shots are max ranges is simply something that is not usually done. There's a good reason for it, and it doesn't matter which missile you're using.

 

The one Phoenix missile that was successfully fired at an Iraqi Mig (23 or 25) missed when the Mig turned tail and ran for it. Iran claims some successful intercepts, but not a lot is known about those (and Iran claims a lot of things).

 

Which ... Phoenix? When? I'm well aware of the two last ones ever launched missing ... because the batteries had not been maintained and the missiles flew flat out dead.

 

I've not only read this numerous times, and seen it in numerous documentaries, but all the known threats of the period and the Navy's doctrine at the time support this.

 

"Poor terminal maneuvering characteristics" was in the context of engagement at its max range, and in part due to the ballistic trajectory.

 

Compared to an AIM-9 against a fast, small and highly maneuverable target, yes, the maneuvering characteristics can be considered poor even closer in.

 

I suggest reading actual employment manuals, if you can find them, not ... documentaries or wiki.

 

The Phoenix missile could not be used against multiple targets at maximum ranges, you'd be shooting singles. Blame the mid-course guidance method.

[fltsimbuff]

Your assumption isn't correct. If you engage bombers or cruise missiles at very long ranges, you MUST use STT. This immediately negates launching on multiple platforms. This means that any TWS launch, be it against a bomber or a fighter, is quite likely to be well within kinematic capability.

 

See Below.

 

Not only that, but shots are max ranges is simply something that is not usually done. There's a good reason for it, and it doesn't matter which missile you're using.

For targets rapidly moving toward you, on which you have a good solid lock, there's plenty of reason to do so.

 

Which ... Phoenix? When? I'm well aware of the two last ones ever launched missing ... because the batteries had not been maintained and the missiles flew flat out dead.

 

I believe it was during the first Gulf War. 2 firing attempts were made that fell like bombs (the ones you are referring to) and a third actually launched properly (different engagement).

On a somewhat related note, I read in a few places that Iran claimed they didn't use the "lofting" mode much, which probably means they fired it at shorter ranges (I've never heard of it being selectable, but as the minimum range was about 2nm it wouldn't be "lofting" at that distance). Again though, Iran claims a lot of things.

 

I suggest reading actual employment manuals, if you can find them, not ... documentaries or wiki.

 

You can invalidate as many information gathering methods as you want, but I'll take any one of those over the word of one dude on a forum. It's not like I am seeing a single reference and believing it zealously. I would expect you to also prefer whatever sources you've got over anything I say. Unless you can point me at some sources?

 

The Phoenix missile could not be used against multiple targets at maximum ranges, you'd be shooting singles. Blame the mid-course guidance method.

 

Where do you get that it could not be used except in STT made at maximum ranges? Not only have I heard it was used at over 100nm against 6 targets at the same time from 1 ship during testing, but the way the AWG-9 works, that makes no sense. Remember the guidance of the AWG-9 when guiding Phoenix missiles was not like regular SARH missiles or radars. AWG-9 remembered tracks and used spotlighting, not a constant track. The mid-course guidance did not require constant illumination.

[fltsimbuff]

Here are some resources describing the original mission of the Phoenix, so we can put that to rest. I've included links so you can take a look at the context:

 

- "The Naval Institute Guide to World Naval Weapons Systems, 1997-1998" by Norman Friedman

-- "...although conceived as an antibomber weapon, Phoenix can shoot down antiship missiles.."

-- Lots of good information on guidance and on tests. Note none of the tests referred to maneuvering targets.

-- Google Books Link: https://books.google.com/books?id=l-DzknmTgDUC&lpg=PA427&dq=aim-54&pg=PA427#v=onepage&q=aim-54&f=false

 

- "Persian Gulf War Encyclopedia: A Political, Social, and Military History" edited by Spencer C Tucker

-- "Developed by Highes Aircraft Company and Raytheon beginning in the late 1960s to meet the threat posed by Soviet long-range bombers carrying antiship missiles, the Phoenix entered service with the U.S. Navy in 1974."

-- Google Books Link: https://books.google.com/books?id=-oaMBAAAQBAJ&lpg=PA6&dq=aim-54&pg=PA6#v=onepage&q=aim-54&f=false

 

- "Iranian F-14 Tomcat Units in Combat" by Tom Cooper

-- "... Hughes AIM-54 Phoenix air-to-air missiles, which were required by the US Navy to intercept the formations of Soviet bombers considered to pose the greatest threat to its fleet of aircraft carriers."

-- Google Books Link: https://books.google.com/books?id=MCzk0cARvjAC&lpg=PA88&dq=aim-54&pg=PA8#v=onepage&q=aim-54&f=false

 

- "F-15 Eagle Engaged: The World's Most Successful Jet Fighter" by Steve Davies, Doug Dildy

-- "The AIM-54 Phoenix was specifically developed to be a very long range 'bomber destroyer' missile..."

-- Other interesting notes about guidance issues against more maneuverable threats during mid-course guidance that I wasn't aware of. The author seems a bit biased against the Phoenix, so not sure we can trust that 100% though

-- Google Books Link: https://books.google.com/books?id=wBRM5RRWZ3oC&lpg=PA88&ots=Owy_fM8905&dq=F-15%20Eagle%20Engaged%20phoenix&pg=PA88#v=onepage&q=F-15%20Eagle%20Engaged%20phoenix&f=false