Noise Limits for FAI

[Amram Privat]

Oppss..typo... see correction in red...
  ----- Original Message ----- 
  From: Amram Privat 
  To: discussion at nsrca.org 
  Sent: Monday, June 27, 2005 10:04 AM
  Subject: Re: Noise Limits for FAI


  Hello Bill
  Just finished series of tests with OS140RX  20% nitro 17% oil.
  OS header and ES 20" CF tune pipe and Hyde ARIA mount. Test is 3 meters from the model on grass field:

  APC 17x12       2 blades = ~ 91.5 - 93dB   (Very powerful but risky for competition and slow down rate is low)
  APC 16x14       2 blades = ~ 89 - 90dB      (Powerful but fly too fast slow down rate is low)
  APC 16x12       2 blades =    Not tested yet
  APC 15.75x13  3 blades = ~ 88 - 90dB      (Good performance, slow down rate is better but not enough)
  APC 15.5x12    4 blades = ~ 86 - 88dB      (Best flying on normal conditions. Will have not enough power on strong windy day, very good speed control)

  Not tested but I am tending to think that for YS160 the 4 blades will be a good solution.

  Amram


    ----- Original Message ----- 
    From: Aviram Arbel 
    To: discussion at nsrca.org 
    Sent: Monday, June 27, 2005 9:35 AM
    Subject: RE: Noise Limits for FAI


    Hi Bill
    I'm using APC 4 blade 15.5X12 30% CP - 87-89 DB 

    Aviram



----------------------------------------------------------------------------
    From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On Behalf Of vicenterc at comcast.net
    Sent: Monday, June 27, 2005 3:50 AM
    To: discussion at nsrca.org; discussion at nsrca.org
    Cc: William Ahrens
    Subject: Re: Noise Limits for FAI


    Hi Bill,

    Did you check wiht 3 or 4 blade prop?  Probably you could reduce it wiht those props.

    Vicente

      -------------- Original message -------------- 

      > Group 
      > 
      > For a YS 160 what prop and exhaust will get me to 94dB(A) and work well. 
      > 
      > Currently using a 17 x 12 wide with EX Composite pipe and 30 percent Nitro. 
      > Today at about 101 degrees heat index my plane measured about 98dB(A) with a 
      > Radio Shack meter. 
      > 
      > Thanks 
      > Bill 
      > 
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