Why don't they use sound as a way to approximate where a plane is, like they do with radar and heat..
I guess sound is too slow? But those things are loud af.
Why don't they use sound as a way to approximate where a plane is, like they do with radar and heat..
sound moves at 666 knots (yes, really)
an F35 moves at 700 knots
Surely an f35 is much faster than that.
Being faster than sound is pretty fast anon
It is, at higher altitudes it can do about 1066 knots. But at sea level its top speed is 700 (or so they want you to think)
>661.5kts at sea level
>638kts at FL100
>473kts at FL400
Vade retro me satana. Maybe in Death Valley, or something, but not in the skies.
It was experimented with in the early days of WW2 and worked fairly well.
The problem is most planes cruise at transonic speeds so you won't actually hear them before they've already launched a missile at you
I wonder why...
Echolocation was a thing in the 1930s, especially in England but it was useless even against props flying at 400 km/h.
You're thinking of submarines.
It might against A50s then.
Sound travels very slowly and not very far and is also subject to a ton of environmental distortion, so it's pretty shit for anything.
Speed isn't actually a huge issue. If the plane is going supersonic yeah you'd only know where it was, but F-35 doesn't spend most of its flight time supersonic which is an enormous fuel sink, it doesn't supercruise. That said there are lots of issues:
1) Precision: knowing "roughly" where an aircraft is doesn't buy you a ton, vaguely in might sorta be of some minor value in a huge country for tactical response but it's not a firing solution. "Aircraft is somewhere in that 10x10 mile square" doesn't get you a missile intercept.
2) Scalability. Sound doesn't travel very far by aircraft standards, so you need an ENORMOUS number of networked directional microphone arrays, everywhere, to get even to "somewhere within a few miles". It's not technically impossible to deploy millions/tens of millions of them, including connections and power even in the middle of nowhere, and maintain them, but it's a pretty big pita for not much gain.
I'll add to that extra regarding #1 it's worth remembering "stealth" is NOT "cloaking device". You can often still "detect" a stealth aircraft on radar, roughly. But if you can't detect it accurately enough and early enough (because SAMs have limited delta-v like all rockets) then it doesn't matter that you sort of know where stealth aircraft are in your airspace firing HARMs at your radars and obliterating your SAMs and your unstealthed fighters. Stealth and ewar only needs to be good enough to shift the balance against AA. Mic grid buys you nothing over radar there.
Modern jets are really fast and fly at high altitude. That makes sound based detection probably kind of suss. Of course if your enemy is spamming loads of low altitude flying mopeds that can't fly faster than a WW1 plane...
https://www.twz.com/land/thousands-of-networked-microphones-are-tracking-drones-in-ukraine
Sound was too slow 80 years ago. By the time you hear the plane it's practically on top of you.
Picrel. Britain tried to use sound during WW2 but found it was too slow and switched to radar.
not really because your LPs will be on border but most targets will be inland and phone call is speed of light.
Yes, this is another reason why Stealth is a hoax.
My $200 SEEK Thermal on my phone says its limited to IIRC 600yrds but it will track police helicopter's heat sig at several miles against night sky, and its not even the "extended range" model.
They switched to radar because it was better, and no one was doing anti-radiation homing missiles, not because sound didn't work.
A "Hogan's Heroes" episode was about a new silent experimental airplane engine and was based on facts.
BTW, Hogan's Heroes remains the best source of info on WW2 in Germany especially "Camp life" for today's scholars. Delousing and showers is frequently mentioned and at least "showers" is something Hogan bargains to get more of.
Colditz > Hogans Heroes
>hear jet engines in the night
>call in your local guy with a thermal scope
>"uhh yeah nah I heard it like east-ish? idk man I was jackin it on the toilet and wasn't paying attention good luck"
>"no no it went left to right not back to front trust me he was there"
more like a billion PLA aux agents one every two miles with a $5 mic on their networked $99 but better than iFone that calcs not just speed but angle change and thus height, and sends to headquarters.
with this mighty power you might be able to tell where an airplane was 3 minutes ago sometimes
implessive
PS-have some explain how a comedian can make sound of a car coming and going and everyone understands what it is.
What has anything you said have to do with sound?
Take your meds, schizo.
Passive acoustic detect-and-avoid is absolutely the key to autonomous small drone operations so they don't collide with other things.
The important part is that you have to do all the processing onboard the craft, because it has to be able to keep operating at all times, even if the datalink gets interrupted somehow.
Active stuff like radar takes a lot of battery power that reduces the flight time, and requires a continuously operating radar array. Onboard video processing (like Tesla Autopilot) is super also takes a ton of power because it's super processor intensive, and requires expensive externally mounted high-definition cameras.
Microphone arrays are relatively cheap and audio processing is can be done without nearly as much processing power.
The Russians were doing acoustic experiments in the artic during the cold war. Of you have enough listening posts ahead of your air defense it would War..
It was discovered in empty bases the Russians abandoned. The same mission the Fulton extraction was invented to get into the abandoned outposts and out again.
>of
If
>war
Work
I need to stop phoneposting.
>tfw learning french so i had to turn off autocorrect
The comprehensibility of my posts has not recovered since ;_; no matter how much I proofread
you need to stop posting period. you don't understand stealth and aren't equipped to make any assertions about it
It works as long as the plane flies slower than the speed of sound.
Could work with drones but since we have radar, lidar and very fancy cameras with AI I don't see it being very useful.
I think the point is if you put some listening devices on those high altitude solar powered aircraft in the artic you could detect even stealth aircraft at least coming your way so you can have more time to prep your anti air defense before your short range radar could pick up said stealth craft. Especially since stealth bombers are designed to angle their nose output upward so you can't hear them on the ground.
It wouldn't be very accurate but at least you could tell something was coming.
They did that for nukes, they were called "flying saucers". That's what crashed at Roswell. A spy balloon carrying testing equipment that's why a dumbass said "some of our flying saucers have crashed". They were large metal disks containing a tympanic membrane. Much like the ocean differences in density create a region in the atmosphere which can bounce sounds long distances. The US originally used this principle to make metal spheres that downed pilots could drop into the sea which would implode at a certain depth and their location triangulated via listening posts. The reason they knew about everybody else's atmospheric nuke tests was because they could hear them.
Unfortunately the sky is pretty loud these days. So finding an aircraft not flying at a specific altitude needed to propagate its sound long distance isn't really viable.