While heat-seaking missiles are very effective anti-aircraft weapons, I always wondered why no missile has ever used sound as a guidance system.
In a way, it would be no different than a submarine's passive sonar system. Basically, you have a sensitive microphone, hooked up to an amplifier and a device that cancels background noises and focuses on the frequencies of the sound of jet engines.
Jet engines have a very typical sound, and every type of jet-engine sounds different, just like every ship prop sounds slightly different. This would make it possible to quickly and accurately identify the type of aircraft as well. (Result: non-military aircraft will be identifid before launch and are never at risk.)
Fighter jets would not be able to fire decoys to distract the missile either. After all, a decoy would have to produce the EXACT same sound as the jet engine, at the same or higher volume to even have a slight chance of succes.
The technology is there, and in operation every day on board of hundreds of submarines worldwide. So why not use this technology in anti-aircraft roles?-- akumabito, Nov 10 2005 Anoying Noise Guided Missiles Annoying_20Noise-Guided_20MissilesHalfbaked by yours truely for different applications [discontinuuity, Nov 10 2005] Sound Seeking AA Missiles Sound-seeking_20AA_20MissilesThe above link got confused. It needs to go to a psychiatrist. [DesertFox, Nov 12 2005] Bass Seeking Missile Bass_20Seeking_20MissileMy take on this idea. [phoenix, Sep 11 2008] Hammerhead missile http://www.fighterf...aft/buzzbomb-v1.php [normzone, Sep 11 2008] Because modern aircraft travel faster than the speed of sound?-- DrCurry, Nov 10 2005 Yes, but it would be convenient to have a missle powered by a AA battery.-- normzone, Nov 10 2005 Not to mention trying to lock on to the sound of an aircraft a mile or so away while there's a rocket burning a couple of feet behind the microphones.-- wagster, Nov 10 2005 They must have fixed that for regular heat-seeking missiles.-- DrCurry, Nov 10 2005 Okay, so not only is it impossible, it's also highly impractical and has a few teething issues as well...-- moomintroll, Nov 10 2005 // (Result: non-military aircraft will be identifid before launch and are never at risk.) //
AWACS (707 or 767 based) KC-10 tanker (DC-10 based) "Wedgetail", a new AWACS for Australia (737 based) "MMA", or Multi Mission Maritime, an in-development sub-hunter (737-based)
The list goes on, but those are just off the top of my head.-- Freefall, Nov 10 2005 The microphones don't necesarily have to be mounted on the missile of course. If you'd have multiple mic's on the ground, you could triangulate the source of the sound. Again, this is proven technology already in use in some US cities to locate the position of gunfire. The military also uses it to pinpoint the location of snipers.
furthermore, AWACS systems are great, but how many airforces can afford their own AWACS systems? Surely you wouldn't want to deny small countries the opportunity to defend themselves when neccessary?
And while it is true that many airplanes can travel faster than th speed of sound, it is also true that most combat airplanes do not. Especially groun- attack aircraft rarely break the sound barrier. All bombers are sub-sonic, not to mention helicopters.
I think that should take cae of the main objections... :)-- akumabito, Nov 10 2005 "Okay, so not only is it impossible, it's also highly impractical and has a few teething issues as well"
And that makes it unsuited for the Halfbakery how...?-- DrCurry, Nov 11 2005 I'm voting for it just 'cause it's funky.-- bristolz, Nov 11 2005 I wonder about the effectiveness of silhouette targeting ordinance? The sound barrier is not as big of an obstacle. The code, I think, is of the same difficulty or less.
Flak is a big problem for such a targeting system, but a passive visual recognition system is only detectable by active scanners. Is a small missile big enough to alert & fast enough in detection to allow for pilot response to the threat?-- Zimmy, Nov 11 2005 [admin: idea renamed Sound-seeking AA Misiles -> Sound-seeking AA Missiles]-- st3f, Nov 11 2005 ... the brass band never knew what hit them...-- etherman, Nov 11 2005 If Jupiter made a noise it could nuke it out. How about " It's another dreary weapons system idea" seeking text missile? - like this one.-- xenzag, Nov 11 2005 [Picturing sound seeking missile, small enough to be powered by AA batteries, chasing it's tail in circles as it attempts to catch up to it's own sound]-- normzone, Nov 11 2005 Why not just use heat as a sensory device..all jet engines put out heat. Or how about micro-wave length RADAR. (oh..yeah these are already in use) If you want something really new...what about a missile that follows ionized gas trails in the atmosphere...or one that tracks burned hydrocarbons...put it in the exhaust trail of the enemy ac and let her rip.-- Blisterbob, Nov 11 2005 AA = anti-aircraft-- discontinuuity, Nov 12 2005 No! You don't say!-- DrCurry, Nov 12 2005 In the UK we have an organisation called the A.A. The Automobile Association - which does the same thing as triple A in the USA - i.e. takes for ever to come and fix your broken down car when you call them - so an A.A. sound seeking missile might be a good idea after all. They could lock unto the sound of the cracking radio in the nearest A.A. breakdown van, streak out and attach themselves to it with a rubber sucker. The driver would then follow the smoke trail back to your vehicle, or be guided by a small yapping gremlin who would pop out of the missile - I'm invading your idea and giving myself a +-- xenzag, Nov 12 2005 And there was I thinking this was about blowing up meetings of recovering alcoholics. Thanks for putting me straight [xenzag].-- wagster, Nov 12 2005 We have an association called AA in the US which I suspect would benefit a *lot* of Halfbakery contributors...-- DrCurry, Nov 12 2005 <Innocently> An anti-aircraft organization?-- moomintroll, Nov 12 2005 // So why not use this technology in anti-aircraft roles?//
cos it's not nice to blow stuff up-- daaisy, Nov 12 2005 Be vewy vewy quiet.-- 2 fries shy of a happy meal, Nov 12 2005 I'd be worried about farting at an inopportune time and with an inopportune sound that would hijack the missle I just sent at my enemy's fight jet and find myself on the recieving end of my own toy.. As a side note, I have toyed around with the idea of cluster rockets that each have a different form of detection and communicate with each other wirelessly to maintain an accurate target picture. Plus I think it would have a greater psychological effect on the pilot seeing a string of missles chasing him as opposed to one single missle.-- scott_r_uber, Nov 12 2005 [akumabito] Sonar is fine for underwater use, as most underwater vehicles travel relatively slow, yet sound travels faster underwater than in air (approx 1500m/s in water, compared to approx 330m/s in air).
And even if the target plane is not travelling faster than sound (eg Mach 0.5), sound still travels relatively slow in air (even slower at high altitude). If the plane is travelling accross the missiles path (eg at a distance of 2000m), the missile is going to turn in the direction the plane WAS (in this example: 6 seconds before = 1000m from where it really is...)
Possible use for your idea would be in air combat re-enactment using relatively slow R/C model planes. Using directional mics to steer a small rocket would be relatively cheap, and within the budget of hobbyists. Thanks for the idea, I might give it a go, so [+].-- JoeyJoJoShabadoo, Nov 13 2005 A sound-seeking missile can still follow a supersonic aircraft; it just has to wait until the aircraft passes to hear any sound.-- sninctown, Apr 09 2006 Shirley it would lock on to launcher, pull a 180, and attack the person who launched it.
Missiles are very loud when launching. They are loud all the time; maybe it would lock onto itself and commit suicide.-- DesertFox, Apr 10 2006 As warhead mass tends to decrease as missile avionics get more complex and heavier, AA missiles in the future are likely to tend towards offset aiming to target the most vulnerable points on the airframe like the cockpit, rather than the engines, which are pretty strong.This is rather more difficult to emulate with sound guidance, and your missile will start to resemble a hammerhead in an attempt to improve imaging resolution.-- AbsintheWithoutLeave, Sep 11 2008 random, halfbakery