[quote="n7188u"]Today I finally had a chance to get a longer flight in. It's
hard
to say how much improvement the install of the sound deadening material on
the air box has on the internal noise. But there is certainly improvement!! The
flight today was very pleasant and more enjoyable. But what really struck me
is that, as A51 experienced, I had to lower the intercom volume quite a bit
since
it felt too loud. Same thing when I was playing music as I generally do.
So, even though I can still hear relatively high frequency sound, but maybe
less,
it seems that overall there is a reduction in noise.
But, I have to admit this is all just based on perception. It is indeed hard to
quantify the change. But I have to say that despite the increase in weight, it
is a keeper.
On a different note: I finished rebuilding my spray booth and getting closer to
starting the painting process. I will hold off taking the airplane apart this
week to see if I fly it to Sun n Fun but by next weekend it will come apart so
no more flying until it is done. I also have a couple of pending jobs I want
to perform on the airframe.
Chris[/quote]
Chris, i noticed you mention calc on the added mass of your air box being 0.6kg.
This aligns with the lower density of products out there. The affects will be
reduced... Adding a second layer will bring the results closer to what the DCI
product has provided, but will of course add another 0.6kg.
Reviewing the graphs demonstrates the db reduction achievable for a given rpm.
The average is 10db but some points it is as much as 25db... the high frequency
vibrational load upon the carbi rubbers is reduced as well as a result.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510532#510532
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