The idea here is an alternative to flash-bang grenades which are pretty nasty in terms of starting fires, blowing limbs off people, etc.
The idea is to have a large grenade-sized gas generator (essentially a solid fuel rocket motor) that vents the exhaust through a high pressure whistle. You should be able to get a good 5 seconds or so of high flow rate, high pressure gas through the whistle. A whistle running at several tens of bar should be able to be incredibly loud.
If you really need to you could put some metal particles in the fuel mix to retain the bright exhaust, but this is almost guaranteed to start fires and maim people, which is what we're trying to avoid.
Some permanent hearing damage may result.
Might have to include several nozzles, otherwise it might fly about the room, although this could be desirable....-- Custardguts, Oct 12 2014 air horns wiki http://en.wikipedia.org/wiki/Air_horn [mofosyne, Oct 12 2014] Shock Waves http://physics.info/shock/ [rcarty, Oct 12 2014] // Some permanent hearing damage may result //
Why not go all the way and make this as bagpipes? Then you can add post-traumatic stress to the effects.-- 8th of 7, Oct 12 2014 So that's why they have army pipers!
In which case - well baked.
//several nozzles// You see...-- pocmloc, Oct 12 2014 This is horrifying.
Next: pyrotechnic vuvuzelas-- sninctown, Oct 12 2014 Likely exists. Can't find.-- rcarty, Oct 12 2014 //Likely exists. Can't find.//
Me neither, that's why I posted it. I was trying to come up with ways to reduce the number of horrifying injuries caused by flashbangs, and another part of my mind was wondering how loud you could make a whistle, and how to do so.-- Custardguts, Oct 12 2014 I could have one of these made before I walk out of the hardware store.-- rcarty, Oct 12 2014 Captain Von Trapp, Sounds of Music-- pashute, Oct 12 2014 There is air horns out there in hardware stores, wonder if they can be modified to act like what you are saying in this idea.-- mofosyne, Oct 12 2014 Need louder and less prolonged, so the entire sound energy produced by the air-horn in as short a time possible, without fragmentation of the pressure vessel. Conceptualize the device as a large cone fabricated from rolled sheet metal. First the device must produce a high pressure fluid inside the cone, a barometer measures the internal atmospheric pressure and is rigged to launch a projectile that is inside the cone. The projectile needn't be too large but simply has to generate supersonic speed inside the fluid, the object is a whistle. So still a kind of airhorn, but one that uses an object moving at supersonic speeds through a pressurized fluid.
Because the projectile is launched from the barometer at the base of the cone, and travels while compressing air into the tip of the cone, 1.21 gigawatts of energy will be required to get the 'delorian' to 88 miles per hour. Using double vertical infinities, instead of a known supersonic speed, twice the required infinities are produced.
Alternatively a diaphragm like the air cannon toy can launch air at supersonic speed creating an air sound anomaly where the pressurized fluid pressurizes the surrounding atmospheric fluid.
[mofosyne] those horns in link are perfect.-- rcarty, Oct 12 2014 random, halfbakery