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The PROS and CONS of helicopters

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Old 17th October 2005 | 06:09
  #21 (permalink)  
20 Anniversary
 
Joined: Mar 2005
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From: West
????

Install a noise cancellation system on the aircraft, would that then create positive calls from those that complain?
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Old 17th October 2005 | 11:43
  #22 (permalink)  
 
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Pro's: flexible and versatile.

Con's: noisy / expensive / noisy / expensive.
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Old 17th October 2005 | 11:45
  #23 (permalink)  
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What really is most upsetting and shows what an ass the legal systems are, is that as a pilot in command you are assumed 'guilty' until you have proved otherwise. Twice I have been investigated and hounded by the authority until in both instances I was able to prove quite clearly my 'not guilty' verdict.
But this was after days of harrassing questioning and an attitude by the investigating officer that one way or the other I was going to be found guilty of the aledged offence. In both cases the 'reporter' was not subsequently charged the cost of the investigation.

Investigating officers ought to present a copy of 'Kiplings' poem so very well presented above to any 'reporter'. That may well save aviation, and therefore us from even more expenses and the harrassment.
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Old 17th October 2005 | 16:39
  #24 (permalink)  
 
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From: Cambridgeshire, UK
"Install a noise cancellation system on the aircraft..."

Des'nay work! Qinetic (UK equivalent of DARPA) wasted lots of money to find out what most engineers already know, with the pointless NXT system (albeit their objective was internal noise). If you could design a system than radiated a phased array of acoustic sources, the power requirement, or system mass, is rediculous. It would at any rate only work on the lower frequencies

The best you can ever do is to minimise the noise sources, then absorb as much of it as you can. Maybe some research into compliant rotor tips, with viscous damping, is required. Rotor blade damping makes sense anyway, to my mind, to reduce aeroflex vibration sources...

Mart

Last edited by Graviman; 17th October 2005 at 18:15.
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Old 17th October 2005 | 19:28
  #25 (permalink)  
 
Joined: Apr 2003
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From: Vancouver, BC, Canada
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Mart,

An external noise project was tested during the Vietnam War. They used a "radiated phased array of acoustic sources" to try and overcome the noise of the rotors during an attack. However, it did not work.

This experiment was depicted during a stealth attack in the movie 'Apocalypse Now'.
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