NDRCC Sound Log    
         
Pilot                  Plane                       Engine           Muffler                  DB             Date
         
Charles Shafer    Pilot Extra 260          DA 50    w / Wild Hare Cannister      96      12/18/10
Johnny Snead    Wild Hare Cap232      3W-60K w/ Bisson muff 24x8 Bunny 96      12/18/10
Nick Bernier       Top Flite F4U Corsair   DA 85 w /Jtec Pitts style muffler     98      12/18/10
Terry Farmer      Aeroworks Ex 260     DA 85 Slimline Inv. Pitts Muffler        96.5    1/08/11
Terry Farmer      Aeroworks Ex 260     DA 85 W/ Pitts Inv. Muffler Cust.     93.5    1/22/11
Gary Mills           TopFlite P-47           DA 85 w/JTec Pitts Muff                  94.5    1/25/11
Terry Farmer      Top Flite GS P-47      DA 85 w/ Jtec inv pitts                   97       2/15/11
Terry Farmer      Top Flite GS P-47      DA 85 w/Jtech Pitts 24x12 zoar       97       3/05/11
Johnny Snead    WH Cap232             3W-60K w/Bisson Muff/24x8 Bunny   95      4/01/11
Terry Farmer      TF GS P-47              DA85 w/Jtec Muff - 25x10 Custom   96      4/01/11  
Charles Shafer    
Gary Mills            F4U Zirolli                 Moki 150 Radial Custom ring  26x14  85.5  
Art Wagner        Symphony              OS 160  EX 24x3" pip APC 18.1 x 10  80.5       
 

Sound Rule (Revised 01-01-2011)

The sound level of all aircraft flying at the NDRCC field shall be subject to a sound check measured with  the Club's dB meter, set to the “A” weighting, slow response and with the windscreen installed.    

The meter may be held or placed on a stand approximately 24" above the ground, crosswind and perpendicular to the side of the aircraft at a distance of 25 feet. The test area should be in the "south infield" area, clear of buildings and the runway. A minimum of a 5 second full throttle engine run is required.

The sound limit for all aircraft flying at the NDRCC field is:

   100 dB   

 All Club Members are empowered to conduct Sound Checks. However, the NDRCC Board may also appoint designated members (Sound Testing Members) to carry out Sounds Checks when an aircraft is suspected of being over the dB limit.

Often minor throttle programming adjustments can be made at the field which will reduce the noise level sufficiently to allow aircraft to continue to fly that day. However, if minor adjustments do not reduce the noise level sufficiently, the aircraft cannot fly at Eagle Field until appropriate  modifications are made.

Common ways to reduce aircraft dB Levels;

·     Use the correct engine application for the model. Excessive engine sizes are hard on airframes and also hard to muffle properly.

·     "Pitts style" mufflers are better than side mounted exhaust diverters. When it comes to mufflers, larger is almost always quieter.

·     Three blade props are usually quieter. Second choice is smaller diameter, higher pitch 2 blade props (example 20 X 10 versus 22 x 8).

·     Canisters and muffled tuned pipes can really reduce exhaust noise if your aircraft has adequate room. Prices are coming down on this stuff ( most now comes from China).

If an aircraft exceeds the sound limit, and there are no commercially available accessories to enable the aircraft to meet the sound limit, the owner may apply for a Waiver from the NDRCC Board by submitting a completed Waiver Application to the Board via the Sound Testing Member. The Board may either approve the Waiver, or make recommendations to help reduce the sound level so that the aircraft is not excessively loud/or agitating to other NDRCC members and require the aircraft to be re-tested following modifications. After reviewing the re-test results, the Board shall decide if a waiver is applicable. If at a future date commercially available accessories become available that will enable the waivered aircraft to meet the specified noise limits, the aircraft shall be modified immediately or not fly at Eagle Field.

Waivers issued in 2010 will remain valid in 2011, but are not exempt from all conditions of the waiver provision.

Turbines are exempt from sound checks.

Sound Checks may be waived for special events when recommended by the Event CD and approved by the NDRCC Board.