Thread by @heatloss1986

On April 3rd, 1965, at 1110 local time, the first air-to-air engagement of the Vietnam War began. This was an attack by MiG-17s on a strike group consisting of A-4s and F-8Es. One F-8 was damaged and made an emergency landing at Danang Airbase. These F-8s were armed with AIM-9Ds.

https://twitter.com/heatloss1986/status/1759096144154530000

For now, I'm going to focus on the US Navy's employment of AIM-9B and D. C will be covered as well, but it had no combat employment as far as I know. 9B had little Navy usage, so I will have to rely on some USAF numbers for its combat performance.

In 1967, a joint USAF/USN study of air-to-air engagements over Vietnam was begun. This would become RED BARON, which provided incredibly in-depth and detailed analyses of aircraft, pilot skill, and weapon systems effectiveness.

Shortly after, in 1968, the US Navy began their own program, focused on missiles only. This would become the Ault report, named after Captain Frank W. Ault.
These are two of the documents I will be drawing from for this analysis of combat performance.

The first thing to keep in mind as we discuss these is the unexpected nature of air combat over Vietnam. At the time, combat was expected to take place at higher altitudes and speeds than ended up being the case.

We'll start with 9B performance. You'll notice here that the percentage of missile system failures is quite low, meaning that China Lake's initial goal of keeping complexity down was successful! However, there were a few specific hardware issues that the 9B dealt with in combat.

The only one I'll cover here has to do with the Mk 303 influence fuze. The 9B suffered from a number of fuze failures, which ranged from failure to detonate to false detonations altogether!

The biggest problem with the 9B was its small engagement envelope, especially against maneuvering targets. The minimum range for the influence fuze was 3,000 feet, but the maximum range against a theoretical 3G maneuvering target was only 5,000 feet!

As you'll note, out-of-envelope failures made up 34% of total launches!

Thankfully, though, 9B performance improved over time. For a time, hits were as low as 10% of total attempts.

The Navy, understanding the limitations of 9B, began limiting usage unofficially. 9D was already a preferred missile, but 9B, being out of production, was increasingly shoved into training roles.

The 9D is where things get more interesting. Nearly half the 9Ds fired hit their target, and only 12% were out of envelope! The 9D, during this time, had the highest ratio of hits to firing attempts.

The increased maneuverability, minimum and maximum range, and the change in motor burn characteristics (slower burn at lower thrust, higher total impulse) helped significantly with expanding the launch envelope.

Against a 3G maneuvering target at sea level, your minimum range could be as low as 1,000 feet and your maximum was around 8,000 feet, leaving over a mile and a quarter total usable launch range!

You'll note here that only one was outmaneuvered.

This chart over time is also far more favorable than that of the AIM-9B's. By mid '67, the percentage of hits was around 63%!

There were some issues, though, that this document does not describe. The Navy had issues with missile assembly across the board, and the AIM-7 suffered the greatest from this. The 9D was not safe from this. Improper assembly led to unscheduled missile disassembly upon launch.

This, however, was fixed later on by simply improving the missile assembly procedures onboard the Aircraft Carriers.

There was one other issue, which, to the best of my knowledge, appears to have caused the four failures to guide. Upon takeoff and landing, the AIM-9D was subjected to significant vibration and high shock loadings, which appear to have contributed to damage of the electronics.

This led directly to a program to develop a fully transistorized AIM-9D. This took time, but it would end up appearing in the last of the rear-aspect US Navy Sidewinders.

So what about 9C? Unfortunately, the 9C was primarily let down by the F-8's radar, and things only got worse from there for the 9C. It had nearly no support or logistics chain, and when combined with the low production numbers to begin with, it was doomed.

9C was recommended to be removed from service in 1968, and the Navy gladly obliged. Its main advantage, in a practical context, was its ability for the seeker head to be slaved to the target tracking solution, meaning that an off-boresight shot could be conducted successfully.

There was, however, already a solution in the works to fill that capability gap. This would be SEAM.

SEAM would hit the fleet in a very short amount of time, in the form of AIM-9G, the topic for my next thread.