The latest advertising blurb continues to make bold claims about its performance including that it has been designed so that any special audible characteristics have been removed. The noise figures are also given a little more accurately as less than 50dBA L10 at 300m.
Bold claims indeed! We remain hopeful that the independent testing that the company claims to have carried out bear this out when it is released.
It does seem a little strange not to have it released yet. Especially since it appears to have such good news.
One particularly interesting note from the advertisement in the Nelson Marlborough Farming newsletter is that they (FMR) make the claim that the fan (the Defender) is 10dB quieter than any other machine on the market. This does tend to indicate that their Amarillo frost fan (which attracts a 5dB penalty because of special acoustic characteristics) would be exceeding the permissible limit in Marlborough. Additionally, the Frost Boss folks should be a bit peeved since their 4 bladed unit is rated to produce 54dBA L10 at 300m. Someone doesn't have their story straight. 
3 comments:
When is this show on? I wonder if how much design info they are releasing on the defender? And the "Remote Monitering" they also mention. It would be good if they could remotely turn the frost fans off.
J Frost can you please do some investigative work for us all?
I believe that the show was a couple of weekends ago (My invite may have been lost in the mail).
I imagine that there would be a relatively limited amount of proprietary information on the technical details they would feel comfortable releasing. There has obviously been a significant R&D effort and FMR would prefer to be able to capitalize on it. Having said that, releasing the information so that other manufacturers could build better quieter machines would be nice, but frankly that's a fairy tale.
The best that can be hoped for is that independent testing confirms the bold claims made thus far on the noise levels. They have made quite a song and dance without presenting proof, so I assume that their confidence is backed up by solid data (it would have to be to put themselves out on such a limb).
I have a couple of pieces of information on manufacture, but all open source (composite manufacture, chord lengths of blade at tip / root, etc) but the interesting information will be things that have been overlooked. I have been given a tip on one particular aspect that I find interesting and I hope that they have done their maths on it, because it has a potential safety concern. I have to do some more maths myself before alarming anyone.
Actually, now that I read back over one particular web page with information on the Defender, it mentions that the noise is half that of other frost fans.
Now half of a value represented in decibels is only a drop of 3dB (half of 60dBA is 57dBA). However the response of the Human ear discerns a difference of half at somewhere between 6 and 10dB difference depending on the 'weighting'. Having heard them talk about a 10dB drop from previous models, I can only assume that by 'half' they mean 10dB?
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