Helicopter Noise Emission research.

[Steve76]

Guys,

I need a push in the right direction to find out specific information regarding the Db ratings of various helo types. Is anyone aware of links pertaining to research done on this previously?

I have no doubt there is lots out there but I would be very interested in the noise signatures of Bell 206L, 205, KA32, CH107, CH234 and Mil 26.

Please and thankyou.

Steve

[madman1145]

Maybe something like this, from the German CAA: http://www.lba.de/cln_009/nn_57316/SharedDocs/download/T/Umwelt/T6__LaermLst3,templateId=raw,property=publicationFile.pdf/T6_LaermLst3.pdf

- madman

[ShyTorque]

Helicopters now have a noise testing and certificate issued as part of the type certification process. The last three types I've operated carry the certificate in the Tech Log.

[rotorspeed]

madman

Very interesting table, well done. Would recommend anyone having a look. Noise is a big issue and will of course become more so. Anyone know what the meaning of the right hand Noise Limit column is - assuming the Noise Level is the actual measured?

No surprises that the B205 tops the table on overflight noise at 97.8dB, compared with around 84 for a B206, 87 for a AS350 and 90 for an A109.

From AS350/355 seems number of engines makes no difference, which is no great surprise, though interesting the Arrius 355N slightly quieter than Allison F at 36.7. NOTAR 900 at 83.5 just quieter than fenestron 135. PT6 S76 quite a bit noisier than Arriel at 95 c/w 93 - is that subjectively reckoned to be the case?

[rotorspeed]

Thanks TS, makes sense.

[No_7DAD]

Torque is quite right. ICAO requirements require the certifying authority to publish the demonstrated noise levels. The 14 CFR Part 36 requires noise testing and Parts 27/29 require they be published in the Flight Manual. So for your selected aircraft, look in the flight manual for the noise certification numbers. You might also view the HAI website www.rotor.com and hit the Fly Neighborly under OPERATIONS for good information
Hope this helps.