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1. 02:22 PM - ICAO Noise Test results RV-10 (Mike Whisky)
2. 03:44 PM - Re: ICAO Noise Test results RV-10 (Bruce Johnson)
Message 1
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| Subject: | ICAO Noise Test results RV-10 |
This might not be of great concern of most RV-10 owners especially in the US but
I consider this still an important environmental information for all the RV-10
owners.
My RV-10 has been built and accepted under Swiss regulations and one part of it
is the noise measurement certificate. Landing tax are based mostly on MTOW plus
a charge for the noise class your aircraft is in. So it was of great interest
to achieve the lowest noise class.
As there was no data available about noise emission of an RV-10 I want to share
my findings.
The main noise sources are the propeller and the engine noise via the exhaust system.
As prop tip speed is one factor I decided to go with a smaller diameter
3-blade MT (MTV-12B/193-53) propeller. The next factor is of course RPM which
I reduced to max 2500. It is quite common for GA aircraft in Germany or Switzerland
to have RPM reduced to 2500 in order to meet the maximal allowed noise
requirements. The next thing is the exhaust system/muffler. There are special
mufflers available like Liese which are quite common to muffle the noise even
further, however I needed my baseline first to make the call to install them or
not and to be able to define its required dB reduction.
My RV-10 has the standard Vetterman 6-3 exhaust system and the above called 3-blade
prop running max 2500 RPM. The test were conducted at MTOW 2700lb /1225kg.
ICAO Noise Measurement Test Scenario
ICAO Annex 16 Chapter 10
- Application accepted from 1988 onwards
One measurement point
take-off flight path with max. take-off power
Noise measured in dB(A)
The measurement crew on the ground takes a picture of the overflying aircraft to
compare the logged overflight altitude reported from the aircraft with the measured
results. At the same time it measures the noise. More factors are taken
into consideration including wind, surrounding surface etc. I had to conduct
6 flights and the average noise values plus the correcting factors result in
the final noise level in dB, which puts me in one of the noise categories mentioned
above.
To make a long story short my RV-10 achieved 77.8 dB which falls under category
D, which is the lowest available.
It is interesting to note that the only other RV-10, which went through the same
test, is equipped with an two place Hartzell propeller (as well reduced to 2500
RPM) and Liese mufflers attached to the Vetterman exhaust pipes, achieved
noise class C. Therefore it looks as if the propeller diameter and probably the
tip form is a major contributor to noise. There might be other contributing
factors such as sound insolation which might work as a reduction of resonance.
For all the builders who are building under a regulation where noise reduction
is a topic I hope that might help to consider propeller choice besides looks,
ground clearance and weight.
Michael
--------
RV-10 builder (flying)
#511
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=427526#427526
Attachments:
http://forums.matronics.com//files/test_procedure_133.png
http://forums.matronics.com//files/noise_category_166.png
Message 2
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| Subject: | Re: ICAO Noise Test results RV-10 |
Another good reason to live in the USofA. Sorry for you Michael=0A-=0AGod
Bless America=0A(please) -:)=0A=0A=0ABruce=0A=0A=0AOn Tuesday, July 29,
2014 2:33 PM, Mike Whisky <rv-10@wellenzohn.net> wrote:=0A =0A=0A=0A--> RV1
0-List message posted by: "Mike Whisky" <rv-10@wellenzohn.net>=0A=0AThis mi
ght not be of great concern of most RV-10 owners especially in the US but I
consider this still an important environmental information for all the RV-
10 owners.=0A=0AMy RV-10 has been built and accepted under Swiss regulation
s and one part of it is the noise measurement certificate. Landing tax are
based mostly on MTOW plus a charge for the noise class your aircraft is in.
So it was of great interest to achieve the lowest noise class.=0A=0AAs the
re was no data available about noise emission of an RV-10 I want to share m
y findings.=0A=0AThe main noise sources are the propeller and the engine no
ise via the exhaust system. As prop tip speed is one factor I decided to go
with a smaller diameter 3-blade MT (MTV-12B/193-53) propeller. The next fa
ctor is of course RPM which I reduced to max 2500. It is quite common for G
A aircraft in Germany or Switzerland to have RPM reduced to 2500 in order t
o meet the maximal allowed noise requirements. The next thing is the exhaus
t system/muffler. There are special mufflers available like Liese which are
quite common to muffle the noise even further, however I needed my baselin
e first to make the call to install them or not and to be able to define it
s required dB reduction.=0AMy RV-10 has the standard Vetterman 6-3 exhaust
system and the above called 3-blade prop running max 2500 RPM. The test wer
e conducted at MTOW 2700lb /1225kg.=0A=0AICAO Noise Measurement Test Scenar
io=0A=0AICAO Annex 16 Chapter 10=0A- Application accepted from 1988 onwards
=0AOne measurement point =0Atake-off flight path with max. take-off power
=0ANoise measured in dB(A) =0A=0A=0AThe measurement crew on the ground take
s a picture of the overflying aircraft to compare the logged overflight alt
itude reported from the aircraft with the measured results. At the same tim
e it measures the noise. More factors are taken into consideration includin
g wind, surrounding surface etc. I had to conduct 6 flights and the average
noise values plus the correcting factors result in the final noise level i
n dB, which puts me in one of the noise categories mentioned above.=0A=0ATo
make a long story short my RV-10 achieved 77.8 dB which falls under catego
ry D, which is the lowest available. =0AIt is interesting to note that the
only other RV-10, which went through the same test, is equipped with an two
place Hartzell propeller (as well reduced to 2500 RPM) and Liese mufflers
attached to the Vetterman exhaust pipes, achieved noise class C. Therefore
it looks as if the propeller diameter and probably the tip form is a major
contributor to noise. There might be other contributing factors such as sou
nd insolation which might work as a reduction of resonance.=0A=0AFor all th
e builders who are building under a regulation where noise reduction is a t
opic I hope that might help to consider propeller choice besides looks, gro
und clearance and weight.=0A=0AMichael=0A=0A--------=0ARV-10 builder (flyin
g)=0A#511=0A=0A=0A=0A=0ARead this topic online here:=0A=0Ahttp://forums.mat
ronics.com/viewtopic.php?p=427526#427526=0A=0A=0A=0A=0AAttachments: =0A
=0Ahttp://forums.matronics.com//files/test_procedure_133.png=0Ahttp://forum
- - - - - - - - - - - - - - - -Matt Dralle, L
=======
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