Tracking multiple AIM-7s

[Gunfreak]

So while the F14 can send out multiple AIM54s and guide them in. It can only guide 1 Sparrow at the time, if you fireca second one it will stop guiding the first one.

But reading about the Vietnam Air war it appears the F4 can guide several AIM-7s (at a single target)

Is this correct?

[av8orDave]

Where'd you get the idea that the F-14 can't guide multiple Sparrows to the same target? To the best of my knowledge, nothing prevents this. It just can't guide multiple Sparrows to different targets simultaneously.

[Stackup]

3 hours ago, Gunfreak said:

It can only guide 1 Sparrow at the time, if you fireca second one it will stop guiding the first one.

But reading about the Vietnam Air war it appears the F4 can guide several AIM-7s (at a single target)

The key here is single target.  The Sparrow is a SARH missile (semi-active radar homing) and needs a constant positive lock, for example an STT (single target track) will work while a mode like TWS (track while scan) that can be used to fire Pheonixes or AMRAAMs won't work with the Sparrow.  The target is painted by the radar and the Sparrow looks for the return from the target to home in.  Therefore, if you're in the Tomcat and launch a Sparrow on a target and then lock someone else and fire again, of course the first missile is trashed, you stopped painting its target.

The only limit to how many Sparrows an aircraft can fire at a single target is how many you are carrying and if you can maintain radar lock.  This works in the F-14, the same as it does in the F-15, F-18, and eventually the F-4.

[Dragon1-1]

23 minutes ago, Stackup said:

 for example an STT (single target track) will work while a mode like TWS (track while scan) that can be used to fire Phoenixes or AMRAAMs won't work with the Sparrow. 

Minor nitpick: the mode you're in while guiding the Sparrow is not quite the same as STT. The only two modes in which Sparrow can be launched is the continuous wave (CW) mode, which is similar to STT in operation, but with a continuous signal from the radar, and Flood, which is also a continuous wave mode, but one that does not attempt to track the target, instead just radiating straight ahead in order to hopefully get enough energy on the target. The Tomcat's two regular STT modes are pulse (PSTT) and pulse doppler (PDSTT), which work differently and do not use continuous wave illumination.

I'm not sure if it's possible to hit two targets with two Sparrows by keeping both in Flood cone, but in such a situation getting any hits at all would be by luck, anyway. I suspect they could go for two different targets in such a situation, but I don't see any way of assuring that. Not to mention it's highly unlikely any two targets would be flying in that manner and not break away from each other the moment they see missiles coming towards them.

Edited November 13, 2023 by Dragon1-1

[Stackup]

3 hours ago, Dragon1-1 said:

Minor nitpick: the mode you're in while guiding the Sparrow is not quite the same as STT. The only two modes in which Sparrow can be launched is the continuous wave (CW) mode, which is similar to STT in operation, but with a continuous signal from the radar, and Flood, which is also a continuous wave mode, but one that does not attempt to track the target, instead just radiating straight ahead in order to hopefully get enough energy on the target. The Tomcat's two regular STT modes are pulse (PSTT) and pulse doppler (PDSTT), which work differently and do not use continuous wave illumination.

I'm not sure if it's possible to hit two targets with two Sparrows by keeping both in Flood cone, but in such a situation getting any hits at all would be by luck, anyway. I suspect they could go for two different targets in such a situation, but I don't see any way of assuring that. Not to mention it's highly unlikely any two targets would be flying in that manner and not break away from each other the moment they see missiles coming towards them.

Thanks for the clarification, I only know how it works in general not all the little details.

[zarusoba10]

I don't know if I should ask here, but I would like to ask about the mechanics of CW Sparrow.

A Sparrow equipped with a CW seeker can obtain the target's relative velocity by comparing the Doppler shift of the CW coming from the mother aircraft (I wonder if there is an antenna on the missile's butt) and the CW reflected from the target. , I heard that this is used to filter ground reflected signals, etc.
Using this method, Sparrow extracts only the signals that appear to have returned from the target and ignores other signals.
Therefore, if the target performs a "beam maneuver" from Sparrow's perspective, the target's relative speed and Sparrow's ground speed will be the same, the ground reflection signal will pass through the filter, and Sparrow will lose lock-on.

Is this correct?

[Bacab]

Technically any RF sensor using Doppler processing to discriminate signals of interests among ground clutter is susceptible to a beam manoeuvre performed by its target (albeit at low altitude and in look down). In this regard the Sparrow is not different. This being said I do not know the particularity of this seeker, I only answer from a general perspective about radar seeker.

[Kalasnkova74]

12 hours ago, Gunfreak said:

But reading about the Vietnam Air war it appears the F4 can guide several AIM-7s (at a single target)

Is this correct?

Yes. Pilots recognized quick that the AIM-7s kill probability (Pk) wasn’t lining up to the brochure and acted appropriately. Multiple AIM-7 shots at one target was not unusual. One flight of four USAF F-4s expended 16 AIM-7s - the entire flights arsenal- at one MiG with no hits. 

[av8orDave]

19 hours ago, Gunfreak said:

So while the F14 can send out multiple AIM54s and guide them in. It can only guide 1 Sparrow at the time, if you fireca second one it will stop guiding the first one.

But reading about the Vietnam Air war it appears the F4 can guide several AIM-7s (at a single target)

Is this correct?

So to directly answer your original question:

- The F-14 can only guide Sparrows at one target at a time, but multiple Sparrows can be fired at that single target. Firing a second Sparrow at a single target won't trash the first missile. 

- The F-4 can do the same. It was common practice in Vietnam due to the low reliability of many aspects of the Sparrow. Sometimes the motor wouldn't fire, sometimes it would fail to track, etc, so pilots started launching a couple to try to up the likelihood of a successful shot.

Edited November 13, 2023 by davidrbarnette

[Dragon1-1]

In fact, the above is true for all SARH missiles. In both Mirages and MiGs it was a common practice to launch both Fox 1s at the same time, because early missiles in general were not particularly reliable. It also let them get rid of two rather draggy missiles in the first pass, then either go home or engage with heaters and guns without worrying about asymmetric loads. We currently don't have this modeled in DCS, but all missiles of that era had a significant chance to fail. Although rough handling, being stored in a damp jungle hut and, in the Navy, catapult shots didn't help the Sparrow's reputation in Vietnam.