2012/12/10

CUDA, torpedoes ... hardware stuff for a change

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Torpedoes are best-launched against an opponent in pursuit, and you're quite safe from them if you run away from their launcher (starting when you're still a good distance away). This simple conclusion is based on the fact that an opponent closing in adds his speed to the torpedoes' while a pursuing torpedoes subtracts the target's speed from his own. The running tactic works because torpedoes aren't very much faster than surface warships (about 30-48 knots versus about 20-36 knots during WW2, for example).
I didn't pull this out of my dark place; it's a classic operational research result. Read Hughes if interested in more of this kind.


Surface warships of the WW2 era had torpedoes as complementary munition; their main munitions in surface engagements were shells (with exception of the Japanese torpedo cruiser Kitakami and even more so Oi). This and to some degree a heavy dose of ignorance about hostile torpedo performance meant that the aforementioned torpedo fight dynamic did not dominate naval battles. Second-best in face of powerful torpedo armament was to attack heads-on (small target area) and outright horrible was the classic Jutland-style battle line
Operational research tells us running in face of powerful torpedoes was best, but military history only tells us the alternatives weren't exactly satisfactory.
I figured it has become quite similar with air2air missiles as with WW2 surface warship torpedoes. This may have been so ever since AIM-120 AMRAAM missiles deleted the need for illumination from medium-range missiles so the shooter could turn and run himself (I suppose short range missiles would rarely allow for a timely escape and are rarely used head-on anyway). Maybe it was even already like this prior to the 90's, with a hunter-killer tactic in which the forward killer fighter fires a Sparrow and runs while a rear hunter fighter keeps the target illuminated with its radar.* (The smaller range of the Sparrow and coordination required would have made it a difficult tactic for head-on engagements, though.)

My understanding was that either way would lead to a huge expense of missiles for few kills if the enemy was smarter than WW2 admirals and understood the dynamic. Missiles would dominate over guns this time, after all. So I figured the typical air campaign between modern air forces would involve a lot of fighters forming almost a line yet moving forward and backward, launching missiles and dodging others'**. That is, unless some technological or training asymmetry overpowered the dynamic.

All this did not fit well to the very small quantity of missiles carried by some fighters; notably F-22, F-35 (which is not primarily a fighter, of course), Gripen - but also typical missile payloads of Hornets, Rafales, Mirage 2000s etc. Only the Russians/Soviets with their Flanker series openly displayed a preference for many (up to a dozen) air2air missiles onboard, followed by F-15 fighters with often up to eight.

So I didn't write about this dynamic - despite at least the non-speculative torpedo thing being really interesting.

Yet, a few days ago I found this about CUDA a.k.a. HTK.

So basically all those "few A2A missiles" fighters may become viable for the 'running forward and backward' skirmisher***-style again, not betting solely on technological asymmetry - and my confidence in the dynamic's relevance to modern fighters grew enough for writing, obviously.
Some glue on the backside of a mosaic stone of the art of war had appeared with these links.




*: This tactic was reportedly used by Swedish Gripen pilots to embarrass some NATO fighter pilots on an exercise. They used AMRAAMs themselves, and instead of the hunter illuminating as was necessary with SARH, he did feed the AMRAAM's computer with info about the target movements via datalink. Meanwhile the launcher platform ('killer') ran.
This is supposedly also the reason for Russian rear-looking radars on some late Flanker versions; a rear-looking radar unites hunter and killer function in one airframe while using the same combat dynamic.
**: Anyone who has ever seen a Navyfield clan war (an interesting online game to watch human behaviour) should know this extremely well from the main fight of the battleships in this game. It has quite the same dynamic despite shells still being multiple times as fast as ships on the scale used by this game.
***: Analogue to European 19th century skirmishers on battlefields and Peltasts.
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