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The AIM-7 Sparrow Missile - Information & Discussion topic


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18 minutes ago, MiG_23M said:

Russian forum did not have the confused emojis, only upvotes.. I think is a much better method. Less toxicity and that's surprising to be honest.

You'd be surprised

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@Gunjob I have another question for you, perhaps you have a source that clarifies the subject further.. but first some context.

 

In-game the F-14 can switch between radar modes "TRK" and "TRK PD HDN" while the target is locked. In real life this should not be possible I would think as there are restrictions stating you cannot fire the AIM-7E-2 after launching an AIM-7F from the PD modes.

 

This means that you would need to either drop the lock for the AIM-7F, or you would lose the track for the AIM-7F if you were to switch from PD to SRC modes and fire the AIM-7E-2. Would you agree? Can you find anything that more explicitly states this in any of your sources?

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7 minutes ago, MiG_23M said:

@Gunjob I have another question for you, perhaps you have a source that clarifies the subject further.. but first some context.

 

In-game the F-14 can switch between radar modes "TRK" and "TRK PD HDN" while the target is locked. In real life this should not be possible I would think as there are restrictions stating you cannot fire the AIM-7E-2 after launching an AIM-7F from the PD modes.

 

This means that you would need to either drop the lock for the AIM-7F, or you would lose the track for the AIM-7F if you were to switch from PD to SRC modes and fire the AIM-7E-2. Would you agree? Can you find anything that more explicitly states this in any of your sources?

I would assume that's more due to the 7F using PD guidance from the HPRF radar and the CW illuminator not being active which the 7E-2 would need for guidance.  I don't have a source for the F-14 lacking that capability but I do know the HPRF AI-24 Fox Hunter in the F.3 can auto switch between PD and Pulse as a target reaches f0. 

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14 minutes ago, MiG_23M said:

@Gunjob I have another question for you, perhaps you have a source that clarifies the subject further.. but first some context.

 

In-game the F-14 can switch between radar modes "TRK" and "TRK PD HDN" while the target is locked. In real life this should not be possible I would think as there are restrictions stating you cannot fire the AIM-7E-2 after launching an AIM-7F from the PD modes.

 

This means that you would need to either drop the lock for the AIM-7F, or you would lose the track for the AIM-7F if you were to switch from PD to SRC modes and fire the AIM-7E-2. Would you agree? Can you find anything that more explicitly states this in any of your sources?

you can not bring both at the sametime

 

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4 minutes ago, Gunjob said:

I would assume that's more due to the 7F using PD guidance from the HPRF radar and the CW illuminator not being active which the 7E-2 would need for guidance.  I don't have a source for the F-14 lacking that capability but I do know the HPRF AI-24 Fox Hunter in the F.3 can auto switch between PD and Pulse as a target reaches f0. 

It should be noted that unlike AIM-7F, which can use either CW guidance or PD (HPRF) guidance, skyflash only had CW guidance mode, so it doesn't matter which mode (pulse or PD) radar is on, as long as there is a CW illuminator pointed at the target, skyflash can be guided.

 

Whether F14 can still guide the missile after swtiching from PD to Pulse requires a lot more research.

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11 minutes ago, Gunjob said:

I would assume that's more due to the 7F using PD guidance from the HPRF radar and the CW illuminator not being active which the 7E-2 would need for guidance.  I don't have a source for the F-14 lacking that capability but I do know the HPRF AI-24 Fox Hunter in the F.3 can auto switch between PD and Pulse as a target reaches f0. 

The Fox Hunter is firing which missile? The AIM-7F has to command roll to shape wings like "X" in relation to the plane from "+" to polarize with the CW antennae on the F-14. Without that roll command it can't polarize and the track would be lost switching to pulse from PD, hence why it cannot fire and guide the AIM-7E-2 after the AIM-7F is launched in PD.

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Here's a question, should the AIM-7M be modelled with inertial guidance like the R-27?  Secondary sources claim that it has an inertial autopilot (the datalink for midcourse correction came later with the AIM-7P however).  Obviously, we don't have the SMC or CS for the AIM-7M yet, so the closest thing to a primary source I can find is p. 113 of the Gulf War Air Power Survey Vol. 4.  It states - citing a T.O., as follows, 

Quote

The major improvement is its new digital data processor, which provides the following: (1) programmability to meet future threats, (2) simultaneous track of two targets within the antenna beamwidth, (3) prediction of line of sight rates to make target fades less severe on missile guidance, (4) tracking and avoiding of main beam clutter, (5) improved performance against advanced ECM, (6) improved fuze arming sequence, (7) improved low altitude performance, and (8) an active fuze.

Point 3 sounds suspiciously like an inertial guidance system was added to the missile.

On 11/04/2023 at 15:11, InterFleet said:

Any sources for inertial navigation for AIM-7M H build?

All I find is circular reference to this mega thread.

:burned:

Maybe this is what you're looking for

Edited by TheSeeker
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3 hours ago, TheSeeker said:

Here's a question, should the AIM-7M be modelled with inertial guidance like the R-27?  Secondary sources claim that it has an inertial autopilot (the datalink for midcourse correction came later with the AIM-7P however).  Obviously, we don't have the SMC or CS for the AIM-7M yet, so the closest thing to a primary source I can find is p. 113 of the Gulf War Air Power Survey Vol. 4.  It states - citing a T.O., as follows, 

Point 3 sounds suspiciously like an inertial guidance system was added to the missile.

Maybe this is what you're looking for

It doesn't have INS, I've discussed this before.

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It seems that English Bias is missing in all Sparrows in-game and their derivatives. English bias would allow for missiles to be put on the correct course, especially in pull-up attacks. Currently AIM-7F is unable to hit targets in vertical launch scenarios. 

In each of these 4 scenarios, the AIM-7F failed to hit in-game. Launch aircraft would be at Mach 0.9 and 500 feet altitude. 

Target aircraft would be at 35,000 feet and Mach 1.1 for example, and it would fail to hit. 

 

AIM-7F_snap_up_test.jpg

 

 

This would fail to hit. So despite the AIM-7F being correctly configured aerodynamic wise, it seemed then that the guidance isn't configured correctly, so I reported it: https://community.gaijin.net/issues/p/warthunder/i/X2wQDdY1kmz1

 

However, I was interested to still dig in further and find out what exactly wasn't configured correctly on its guidance. 

 

 

It seems that it is missing its English Bias. This source states that a very early Sparrow variant, Sparrow III6a, had English Bias in it's guidance. This likely means all Sparrows in-game and their derivatives should get English Bias. The source is here: https://apps.dtic.mil/sti/pdfs/AD0368418.pdf
NOTE: WHILE THE DOCUMENTS SAY CONFIDENTIAL, IT IS HOSTED PUBLICLY BY THE U.S. MILITARY.

 

 

Image

This section is clear that they experimented with the removal of English bias, which indicates it had English Bias from the very start in its guidance logic. It even explains that the English Bias occurs while the missile is still on the aircraft, regardless of target altitude, and prior to the seeker locking onto the target. This section can be found on page 4.

 

If you go another page over, it tells you the experiment result of what occurred when English bias was removed versus left included in it's guidance. A missile with english bias is more was more accurate than a missile without english bias in pull-up situations where the target is at a higher altitude. 

 

Image

 

 

Edited by DirectSupport
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  • 1 month later...

Hi guys

 

Due to community requests from users who wished for the main bulk of discussions and responses from this thread, as well as the many developer answers within them, we have restored the topic as best possible in order to comply with the original poster of the previous topics wishes to remove their opening post information to share on another platform. 

 

We hope the restoration of the thread in this way is the best solution for everyone in order to retain as much of the many discussions that took place here whilst respecting the previous OPs wishes also to remove their main post. 

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