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AIM-9D and AIM-9G should have an 18G overload

In game the AIM-9D and AIM-9G currently have a 16G overload. In reality both these missiles should have 18G overloads. A previous bug report about the AIM-9G's overload has apparently been closed, I believe this to be a mistake and will explain why.

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The evidence for 18G


The 18G figure is supported my two separate flight manuals. The first is NAVAIR 01-45HHA-1T F-8 Tactical Manual dated 1 July 1969 updated 1 June 1970. As can be seen it clearly lists the AIM-9D and AIM-9G as having an 18G overload.





The next flight manual is NAVAIR 01-245FDB-1T TACTICAL MANUAL NAVY MODEL F-4B, F-4J, AND F-4N AIRCRAFT dated 1 September 1972. It also clearly lists the AIM-9D, AIM-9G, and AIM-9H as having an 18G overload.






So why was the last bug report closed?


The last bug report on this matter was apparently closed based on this comment chain:


The comment chain mainly refers around this passage of text (see spoiler) from the F-4 manual mentioned above, which claims the AIM-9D and G only differ in SEAM capability, while the H got new actuators. The assumption is therefore made that because the AIM-9H has new actuators it also has a higher overload than the G; and therefore the AIM-9H has the 18G overload mentioned in the manual while the AIM-9G has less. I believe this assumption to be wrong and will explain why below.




The first point I would raise is that the F-4 manual makes a point of listing the track rate as different between the AIM-9D/G and H, if the overload was different it is logical they would list it as such too. Another key piece of evidence lays in the F-8 Tactical manual. It is dated 1 June 1970, which is about two years before the AIM-9H existed, therefore unlike the F-4 manual it cannot possibly be referring the the AIM-9H's overload an must mean the AIM-9G has an 18G overload. This section of the F-4J manual also mentions a 20G overload when referring to SEAM capable Sidewinders (AIM-9G / H), so it seems safe to say that the AIM-9G can pull at least 18G rather than 16G.



So where does the 16 G value come from for the AIM-9D / G?


The original comment which apparently got the bug report closed says these three documents list the AIM-9D (and therefore AIM-9G) overload as 16 G, but this was a mistake and those manual do not actually mention any overload at all. You can read the manuals yourself here, here, and here.



The only source giving a 16G overload is this diagram from History of the Chaparral/FAAR Air Defense System dated 1977





This document gives an overload of 16.5 G (so I'd argue that by rounding we should get 17G in game rather than 16G) for the Sidewinder 1C (AIM-9D), however this is not really a valid source. It is a retrospective report on the development of the Chaparral Air Defense System, which basically consists of modified, ground launched, AIM-9Ds. The thing to note is that the number of Gs a missile can pull is directly related to how fast it is travelling, as ground launched AIM-9Ds would be traveling much slower than their air launched counterparts (on account of having to acetate from stationary, instead of being launched while the aircraft is flying at significant speed), it is logical that a document about the ground launched variant would give a lower overload.




There are two independent flight manuals relating directly to the AIM-9D / G which claim these missiles both have an 18G overload. Gaijin appear to be using a retrospective report for a modified and ground launched version of the AIM-9D as their source for overload (and then rounding down); despite this report being flawed in comparison to other sources available. They are then backing this up based on the assumption that new actuators on the AIM-9H means it has higher G load. Even if we assume this is true (and that is debatable) Gaijin are then also assuming that the 18G in the F-4 manual only applies to the AIM-9H. If we do assume that the AIM-9H has a higher overload (again debatable) a more logical explanation, based off the F-8 manual listing an 18G overload for the AIM-9G, is that the AIM-9G has an 18G overload and the AIM-9H has a greater than 18G overload (possibly supported by the mention of a 20 G overload later in the manual).


Overall it seems logical that two period correct flight manuals claiming an 18G overload, while directly referring to the missiles in question, should take precedence over a retrospective report for a modified and ground launched AIM-9D. 

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  • 1 month later...

  This issue has been previously reported to the Developers for consideration.

Thanks for your report, your interest and support for the game.


Kind Regards, Object187 

Technical Moderation Team

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