Continental Air Defense–The Weapons

We’d originally planned to discuss both the Century Series fighter and their weapons, but decided to make it two posts.

The Air Force began development of guided air-to-air weapons almost immediately after World War II came to a close.  Machine guns and 20mm cannon might suffice for destroying fighters, but not for large bombers,which had proven quite durable in the face of fighter attack. The Navy, faced with its own air defense needs to protect is carriers started their own, completely separate development program, leading eventually to the Sidewinder and Sparrow missile families.  The Sparrow program focused on using a Semi-Active Radar Homing (SARH), and the Sidewinder used a passive Infra-Red (IR)homing seeker.

Starting in 1946,the Air Force worked with Hughes Aircraft to develop what would eventually become the AIM-4 Falcon series of missiles.”* The Falcon series focused on using a common missile frame, with both SARH and IR homing seeker variants.  Test firings began in 1949, but development was slow and the first models didn’t enter service until 1956.

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The Falcon was almost completely optimized for the air defense mission (as opposed to an air superiority mission in a fighter vs. fighter environment). The Falcon’s IR seeker head was cooled by a nitrogen bottle, and it took time for the seeker to cool down, and to achieve lock-on . Achieving radar lock-on for the SARH variants was a lengthy process as well.

Generally, Falcons were launched in pairs, one IR and one radar version, to increase the likelihood of a hit. Unlike most air to air missiles, the Falcon didn’t have a proximity fuse. It had to actually hit the target to detonate. This simplified the missile, and made some degree of sense. It only had an 8 pound warhead, and anything less than a direct hit was unlikely to bring down an enemy bomber.

During the time of the Falcon’s development, the Air Force was in effect three different services. SAC as all about the big bombers. TAC, the Tactical Air Command, was focused on support for ground troops, and the tactical nuclear strike role. It gave little consideration to the air-to-air mission. When TAC began to realize that 20mm guns alone weren’t enough, they were happy to ride the Navy’s coattails and borrow the AIM-9 Sidewinder missile. Only the Air Defense Command was advocating for an Air Force guided missile.  A few years later, when TAC found itself flying the Navy developed F-4 Phantom, they also found themselves armed with not only the Sidewinder, but also the Navy developed Sparrow medium range SARH missile. For some unknown reason, when the Air Force started buying the refined F-4D model of the Phantom, the decision was made to replace the Sidewinder with the Falcon as the jet’s short range IR missile. It was not a happy marriage.  While ADC pilots had learned to use the Falcon quite well, the TAC crews had little training. Further, the limitations on it such as limited cooling time for the seeker, and it’s limited maneuverability, made it a less than wholly successful dogfighting missile. Subsequent US fighters would use the Sparrow/Sidewinder combination. The Falcon seemed destined for an early grave.

But the interceptors of the ADC had been built around the Falcon, with weapons bays designed specifically for it. Further, the entire radar and fire control system of certain interceptors, such as the F-102 and F-106, where wholly optimized to work with the Falcon. And for the air defense mission, it was a successful mission. In fact, the Falcon served until the mid-1980s until the last of the F-106s were retired.

Even as the Falcon was entering service, there was great concern that interceptors would be overwhelmed by sheer numbers of Soviet bombers. The answer was (as with so much else in the 1950s!) nuclear weapons.  A small nuclear weapon would be enough to destroy an entire formation of Soviet bombers. And with its large effective radius, complex guidance wasn’t needed. And so the Air Force developed the Genie (AIR-2) air-to-air nuclear rocket.

The Genie was pretty simple. It had no guidance system. The fire control computer of the launching airplane would determine where to shoot to intercept the target. A timer then initiated the nuclear warhead.  Maximum range was about 6 miles, and the warhead had a yield of about 1.5 kilotons.

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Only one live Genie was ever fired. But from 1957 to 1988, the Genie was in service with the US Air Force, and even armed CF-101 Voodoos of the Canadian Air Force (via a dual key system, where the US would release control of the warhead before launch).

One final ADC weapon merits mention. Unhappy with the small warhead of the Falcon and realizing the limitations of the Genie, the Air Force and Hughes developed a version of the Falcon, designed to be equipped with a very small nuclear warhead. The AIM-26A  Falcon used warheads from the Davy Crockett recoilless rifle, with a yield equivalent of about 250 tons. The missile was SARH guided, and used a proximity fuse. A variant with a conventional high explosive warhead was also developed. It saw little US service, but the AIM-26B went on to be license produced in Sweden to arm their Mirage III and Drakken  fighters as the Rb27. In US service, the AIM-26A was withdrawn in 1972, and most warheads were further converted to equip the nuclear version of the AGM-62 Walleye TV guided bomb.

Finally, we should mention that a further improvement of the Falcon, the AIM-47, while never entering service, lead directly to the development of the massive AIM-54 Phoenix missile that armed the F-14 Tomcat and served to defend US carriers from Soviet anti-ship missile strikes.

Next up, we’ll look at the Century Series fighters that carried the Falcon and the Genie.

 

 

*Air Force (and Navy) missiles went through a number of designation schemes through the 50s and 60s. For simplicity’s sake, we’ll only use the post-1962 tri-service designation system.

7 thoughts on “Continental Air Defense–The Weapons”

  1. Reading a book entitled “Clashes” which detailed air to air victories over North Vietnam by USAF/USN aircrews, the pilots almost to a man hated the Falcon missile. It was unreliable and as you pointed out had to hit the target. When you are fighting a MIG19 or 21 that’s a lot smaller target that is manuvering when compaired to a Bear Bomber that they were designed for.

    I thought Falcon Missiles were cool as a kid making models of the F-102 and 106 because of the shape and the color…which explains a lot of things about kids. Unfortunately some of us never advance beyond that stage. 🙂

    1. Robin Olds especially lead the charge to get the Falcon dumped from the Phantom. He hated it with a passion.

      But I’ve read several accounts from former ADC guys that liked the missile (albeit, in the ADC role, not for dogfighting), in particular, the more sensitive seeker head.

      And yeah, I thought it looked a good deal cooler than the early Sidewinders.

  2. You’ve got the misconception that an MB-1/AIR-2/Genie was intended to be used against a formation. It wasn’t. Lethal radius was around 1500′ (450m). What it provided was an unjammable (since it was unguided and used a time fuze to initiate the warhead) weapon that couldn’t be evaded. The lethal radius was larger than the distance a 2G maneuvering target, like a bomber, could move from its predicted flight path in the rocket’s time of
    flight. With the time fuze, there was no need to try and dope out the most difficult problem of an airburst anti-airgraft weapon – the proximity fuze. The small warhead on the Genie (1.5 kt or so) meant that it could be used safely over the predominately open areas in the Northern USA and Canada.
    It wasn’t an ideal weapon at low altitude, of course. The fireball was small, and the atmosphere would attenuate the radiation to safe levels in about 5,000′(1500m) on the ground. An added bonus was that the radiation flux would disable any nuclear weapons
    carried on the bomber – a big fear at the time was that the Soviets
    were “Salvage Fuzing” – setting up their weapons to detonate if something happened to the carrier airplane over enemy (in our case, that’s us) territory. We don’t know if they actually did or not.

    Source : http://tiny.cc/9d0dl

    1. Every thing I’ve read from CB Colby on has always referred to attacking formations. Having said that, I was always struck by the small size of the lethal radius. as it seems too small to be effective against a large formation. I guess I just kind of pictured Soviet bombers operating in something similar to SAC’s 3 ship cells for mutual jamming support.

  3. It would make little sense to fly nuclear-armed bombers in a formation of any kind. You wouldn’t unload weapons en masse over a single target when a single one anywhere near the target would do the job, and the fratricide problem would make it wasteful. What I got from years of reading rec.aviation.military and the postings of guys like former F-102 and F-104 pilots like Walt Bjornby was that the main point of the nuclear air-to-air missiles was to kill the _weapons_. Bringing down the bomber was secondary, although I’d imagine if you accomplished the first, the second would almost always follow.

    1. Before SAC went to the low-level approach, multi-ship formations, such as the 3 ship cell used over North Vietnam (and indeed, still in use over Iraq in 1991- I saw them with my own eyes) were valuable because of mutual support especially in terms of jamming. Sufficient jamming from a three ship cell could often degrade fire control radar enough that an SA-2 launched at the cell would pass between them, instead of tracking on any one A/C.

  4. But those were for conventionally armed missions. I was never a B-52 crewmember, but I’ll just about guarantee you that no sort of formation attack was ever contemplated. I’ve had email correspondence with a former F-4 driver who sat nuclear alert whose name you would recognize ;-). His target, I seem to recall, was somewhere in Yugo or Czecho slovakia. I was astounded to learn that he knew that the SIOP scheduled his weapon to be something like the twelfth on that target. No mention of a wingman – and in his other writings he stressed that you never went anywhere without one. Except, apparently, on the nuke attack mission.

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