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<br />(although not confirmed as such) can be clearly observed travelling at what has been <br />considered at the speed of sound. This ring is absolutely consistent with the sound of <br />the whistle, Le, it is only observed with the whistle, and clearly travels at a speed <br />consistent with that whistle, In the event that the Cannon is not producing the whistle, <br />the 'ring' is not observed. <br /> <br />In the event that the cannon is not designed correctly, it will not produce the whistle. <br />There are a variety of cannons on the market. Not all of them whistle the same, It is <br />apparent that there is room for research in this area. The effectiveness of Hail <br />Cannons is very dependant on producing the 'correct' whistle. <br /> <br />WHAT IS THE "WHISTLE" AND WHAT DOES IT DO? <br /> <br />We are now in an area of 'explosive acoustics'. While the sceptics of Hail Cannon are <br />arguing that a 'bang' from a blast chamber radiates out in all directions and dissipates <br />J~DidIY. the"y_are_ab$oIuteLy..riaht Howevel',t/'Ie-y-l'lave,e9vioosly -oo-t-been-irla-position - - - - - , , ' <br />---------- <br />to observe the resulting whistle. On the other hand, all Hail Cannon observers have <br />been listening to the whistle disappearing into the distant sky. If we can hear this <br />whistle for periods up to 30 seconds that it represents, which has been travelling at the <br />speed of sound, has travelled a long way! At approx 330 mts/sec (1000 tvsec). <br /> <br />Our research has shown that the Hail Cannon is creating a 'special' wave front of <br />great intensity and power, This is caused by what is known as the 'SOLITON <br />EFFECT'. This effect "vas first observed by Mr Scott Russell of Edinburgh, Scotland in <br />1834. The effect is where the high wave overtakes the low wave, thereby <br />concentrating the energy in the wave front into a very narrow band. This energy is now <br />focused into a wave that is around 1mm to 10mm (,025' to ,250') thick. <br /> <br />Shortly after release from the cannon, the shock wave is subject to the 'Soliton Effect'. <br />Initially the wave emerges as something of a conventional sound wave, As it has been <br />ejected from a specially shaped apparatus in the cannon's neck region designed to <br />create this phenomena. It very soon starts to undergo a change in its form. The high <br />wave which normally follows the low wave has had such a shunt out of the cannon <br />neck that it catches up and passes the low wave. The high wave will now 'lead' the <br />low wave. The science of this effect is that the wave front does remain very intact in its <br />travel. The effect will 'shake violently' the atoms it is passing through. While there is <br />some friction loss, the phenomena of the soliton effect is that the low (slow) wave <br />keeps feeding energy into the high wave, thus maintaining the power level as well as <br />the concentrated nature of the wave, <br /> <br />From the observations we have made over many years and the understanding of the <br />'physics' of the 'Soliton Effect' we now have a clear understanding of what we have <br />been observing as a 'Ring' being driven along with the 'Whistle" of hail cannon energy, <br />Consistent with the soliton effect, we have a very concentrated and powerful wave front <br />travelling at the speed of sound vertically into the sky. Given that we only observe <br />these 'Rings' in certain atmospheric conditions, we must look at 'what could cause this <br />effect and that of the 'whistle'? <br /> <br />7 <br /> <br />Copyright \0 1994 <br />