COZY: Making our airplanes quieter, A response from audio spectrum app developer.


Bill Allen
 

Hi Mike - you could make this exhaust/muffler setup as per the (certified) German Gyroflug Speed Canard……

Bill Allen


On Wednesday, 25 May 2022, Michael Schrøder <michael@...> wrote:
Hello Team... Have anyone invested time/brainpower in how to make our plane quieter from outside?.. I am in test flying and soon to undergo noise certification... (EU rules)

Best regards

Mike Schroeder
Denmark
# 0220, OY-CZY



Den søn. 22. maj 2022 kl. 19.32 skrev Yair Gil <goldcozy@...>:
Hello, 
In matter of noise reduction, I can’t explain, but was told by professional person, that engine cowling made out of Kevlar, affects noise reduction.
Yair

בתאריך יום ו׳, 14 בינו׳ 2022 ב-21:17 מאת <cozypilot@...>:

Hi all,

 Hi 

I have posted recently that I am on a campaign to make my Cozy quieter inside and have gotten some great comments.  I am using an iPhone audio spectrum analysis app called SpectrumView.  It is not cross platform but there are dozens of apps for Apple and Google phones.  I have not found one that works on both platforms. SpectrumView is fully usable for free with no ads and data can be captured by doing a screen shot.  For cheap you can upgrade to recording and many other measurement options.

 

I was curious if the data the app measures would be comparable/calibrated across different model iPhones and got a nice response from the developer; see below.

 

It would be interesting if we share measurements here on our forums.  I would suggest we try to do plots with similar conditions, that is, about 135 kn indicated in level flight and the phone 12” or so in front of the pilots face.

 

I hope this is of interest.

 

Del Schier

Cozy IV N197DL

Cannon Creek Airpark 15FL

 

 

 

 

 

 

From: Anil Alexander <anil@...>
Sent: Friday, January 14, 2022 8:38 AM
To: Oxford Wave Research Support <techsupport@oxfordwaveresearch.com>
Cc: delsjunk@...
Subject: Re: SpectrumView question

 

Dear Mr Schier,

 

Thank you for getting in touch with us, and sorry for the delay in our response.

 

First of all, thank you for your positive comments about our software.- given your audio background, we are very glad you think it's good!

 

The Cozy IV looks amazing. I'm astonished about home-built airplanes in general, so very much in awe of what you and the support group are doing.  I happened to be at the Seattle Boeing museum of flight, looking at the Moult Taylor designs (https://www.museumofflight.org/aircraft/taylor-aerocar-iii) in amazement, thinking that the his dream of home planes for people had disappeared over the years. I can see it is alive and well!

 

Your work looks fascinating, and would certainly be interesting to us. We did some work with Airbus many years ago looking at specific frequencies in certain parts of their planes (https://oxfordwaveresearch.com/our-r-and-d/airbus -noise-profiling/) using Spectrumview.

 

Spectrumview takes the input from the iPhone's microphones and although the generally you will get similar results (same frequency range profiles), it will depend on the microphones, models and distance to the noise sources. One thing that we do not do is to measure the absolute noise like an SPL meter. One reason for this is as you say, different microphones may be calibrated differently. 


What would be useful to do however, is to take an average of several seconds of sound and look at the noise profile (see Spectrumview help for more details). Are there certain peaks that occur. Can they be correlated to specific things occuring (e.g. the motor spinning). 

 

We think this could be a fascinating case study, and would love to learn more. If you have anything public facing (blogpost,webpage, etc), do let us know, we would love to understand more.

 

Best regards

-Anil Alexander

 

On Thu, Jan 13, 2022 at 12:33 PM Oxford Wave Research Support <techsupport@oxfordwaveresearch.com> wrote:

Dear Mr Schier,

 

Thank you for reaching out to us about SpectrumView, we are always keen to hear from our users. Many of our users apply SpectrumView to fascinating projects in various areas and it is great to hear about your project. A member from our team will respond to you shortly.

 

Kind regards,

 

Linda

 

Oxford Wave Research Support

www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663


Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

---------

From: <delsjunk@...>
Date: Sun, 9 Jan 2022 at 21:54
Subject: SpectrumView question

 

I am retired from the home and commercial audio business and think that your program is great but I haven’t found much use for it until recently.

I fly a 200 mph 4 seat homebuilt airplane called a Cozy IV. See: Cozy MK IV - Wikipedia It is terribly noisy and I have made a couple of measurements of my airplane, and recently, a similar one that seemed much quieter. A support group of hundreds of people that build and fly these aircraft are interested in sharing plots from your app to help find cabin noise reduction solutions.  We all must wear active noise cancelling headphones to make them bearable to fly in. see attached plots.

<<...>>

My question is; how much does the calibration change from one iPhone to another?  Is there much difference in the mic gain, response and sensitivity between iPhones?

Thanks in advance.

Del Schier

Cozy IV N197DL


 

--

--
Dr Anil Alexander
CEO, Oxford Wave Research Ltd

email: anil@oxfordwaveresearch.com
phone: +44 1865 955250 (office)

phone: +447702157654 (mobile)
www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663

Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

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--
Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

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Izzy
 

I met a Defiant owner in  Norway last month that constructed the exhausts pointing straight up, curving around the cylinder  heads, which appears to help reduce noose by shooting the exhaust note up instead of back or into the ground. Looks like the Speed Canard setup without the muffler.

The tip of a long eze builders plane also showed diffuser holes drilled through. 

I’ve also seen on Nick Ugolini’s exhaust some scalloped tips that seem to have a positive effect. Maybe look at the tips of assault rifle barrels for more inspiration  on noise suppression methods and techniques. 

American operators don’t have to contend with anywhere near the noise issues of Europeans so its hard for us to understand the need for options. 

image

image

Izzy
(603)410-7277

On May 26, 2022, at 02:54, Michael Schrøder <michael@...> wrote:


Hi..

The testing is done at MTOW. You T/O and make a climb out using Vy. At the end of the runway the measuring equipment is located. You fly the "track" minimum 6 times and your noise has to be within certain limits.

The lenght of the RWY, the weather the whatever has to be within specific limits.

Br

Mike

Den ons. 25. maj 2022 kl. 13.14 skrev hnf.flyboy@... <hnf.flyboy@...>:
Is the testing done on the ground or as a flyby? Only things I can think of are a muffler, scalloping the exhaust tips of which there’s not much data or cutting the ends of the exhaust angling down from the top.
I’d like to know more about this as well. 


Sent from the all new AOL app for iOS

On Wednesday, May 25, 2022, 2:10 AM, Michael Schrøder <michael@...> wrote:

Hello Team... Have anyone invested time/brainpower in how to make our plane quieter from outside?.. I am in test flying and soon to undergo noise certification... (EU rules)

Best regards

Mike Schroeder
Denmark
# 0220, OY-CZY



Den søn. 22. maj 2022 kl. 19.32 skrev Yair Gil <goldcozy@...>:
Hello, 
In matter of noise reduction, I can’t explain, but was told by professional person, that engine cowling made out of Kevlar, affects noise reduction.
Yair

בתאריך יום ו׳, 14 בינו׳ 2022 ב-21:17 מאת <cozypilot@...>:

Hi all,

 Hi 

I have posted recently that I am on a campaign to make my Cozy quieter inside and have gotten some great comments.  I am using an iPhone audio spectrum analysis app called SpectrumView.  It is not cross platform but there are dozens of apps for Apple and Google phones.  I have not found one that works on both platforms. SpectrumView is fully usable for free with no ads and data can be captured by doing a screen shot.  For cheap you can upgrade to recording and many other measurement options.

 

I was curious if the data the app measures would be comparable/calibrated across different model iPhones and got a nice response from the developer; see below.

 

It would be interesting if we share measurements here on our forums.  I would suggest we try to do plots with similar conditions, that is, about 135 kn indicated in level flight and the phone 12” or so in front of the pilots face.

 

I hope this is of interest.

 

Del Schier

Cozy IV N197DL

Cannon Creek Airpark 15FL

 

 

 

 

 

 

From: Anil Alexander <anil@...>
Sent: Friday, January 14, 2022 8:38 AM
To: Oxford Wave Research Support <techsupport@...>
Cc: delsjunk@...
Subject: Re: SpectrumView question

 

Dear Mr Schier,

 

Thank you for getting in touch with us, and sorry for the delay in our response.

 

First of all, thank you for your positive comments about our software.- given your audio background, we are very glad you think it's good!

 

The Cozy IV looks amazing. I'm astonished about home-built airplanes in general, so very much in awe of what you and the support group are doing.  I happened to be at the Seattle Boeing museum of flight, looking at the Moult Taylor designs (https://www.museumofflight.org/aircraft/taylor-aerocar-iii) in amazement, thinking that the his dream of home planes for people had disappeared over the years. I can see it is alive and well!

 

Your work looks fascinating, and would certainly be interesting to us. We did some work with Airbus many years ago looking at specific frequencies in certain parts of their planes (https://oxfordwaveresearch.com/our-r-and-d/airbus -noise-profiling/) using Spectrumview.

 

Spectrumview takes the input from the iPhone's microphones and although the generally you will get similar results (same frequency range profiles), it will depend on the microphones, models and distance to the noise sources. One thing that we do not do is to measure the absolute noise like an SPL meter. One reason for this is as you say, different microphones may be calibrated differently. 


What would be useful to do however, is to take an average of several seconds of sound and look at the noise profile (see Spectrumview help for more details). Are there certain peaks that occur. Can they be correlated to specific things occuring (e.g. the motor spinning). 

 

We think this could be a fascinating case study, and would love to learn more. If you have anything public facing (blogpost,webpage, etc), do let us know, we would love to understand more.

 

Best regards

-Anil Alexander

 

On Thu, Jan 13, 2022 at 12:33 PM Oxford Wave Research Support <techsupport@...> wrote:

Dear Mr Schier,

 

Thank you for reaching out to us about SpectrumView, we are always keen to hear from our users. Many of our users apply SpectrumView to fascinating projects in various areas and it is great to hear about your project. A member from our team will respond to you shortly.

 

Kind regards,

 

Linda

 

Oxford Wave Research Support

www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663


Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

---------

From: <delsjunk@...>
Date: Sun, 9 Jan 2022 at 21:54
Subject: SpectrumView question

 

I am retired from the home and commercial audio business and think that your program is great but I haven’t found much use for it until recently.

I fly a 200 mph 4 seat homebuilt airplane called a Cozy IV. See: Cozy MK IV - Wikipedia It is terribly noisy and I have made a couple of measurements of my airplane, and recently, a similar one that seemed much quieter. A support group of hundreds of people that build and fly these aircraft are interested in sharing plots from your app to help find cabin noise reduction solutions.  We all must wear active noise cancelling headphones to make them bearable to fly in. see attached plots.

<<...>>

My question is; how much does the calibration change from one iPhone to another?  Is there much difference in the mic gain, response and sensitivity between iPhones?

Thanks in advance.

Del Schier

Cozy IV N197DL


 

--

--
Dr Anil Alexander
CEO, Oxford Wave Research Ltd

email: anil@...
phone: +44 1865 955250 (office)

phone: +447702157654 (mobile)
www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663

Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

--
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To view this discussion on the web visit https://groups.google.com/d/msgid/cozy_builders/01b901d8097b%2456a1a090%2403e4e1b0%24%40comcast.net.

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--
Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
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To view this discussion on the web visit https://groups.google.com/d/msgid/cozy_builders/CAJe-_p-fQM_mrhSDMCtGRQ_rohN%3DL_9S4vJid%3DsWL3gXtJyyyQ%40mail.gmail.com.


--
Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cozy_builders+unsubscribe@....
To view this discussion on the web visit https://groups.google.com/d/msgid/cozy_builders/CAJe-_p9VooJSHN3eP%3DkNePc-nonBiM%2Bs8EXiaWpxK26fq343Fg%40mail.gmail.com.


John Lambert
 

Increased drag!

 

From: 'Izzy Briggs' via COZY Builders Mailing List [mailto:cozy_builders@...]
Sent: Thursday, May 26, 2022 7:34 AM
To: Michael Schrøder
Cc: hnf.flyboy@...; Yair Gil; Del Schier; Canard Forum; Canard Aviators; Cozy Group
Subject: Re: COZY: Making our airplanes quieter, A response from audio spectrum app developer.

 

I met a Defiant owner in  Norway last month that constructed the exhausts pointing straight up, curving around the cylinder  heads, which appears to help reduce noose by shooting the exhaust note up instead of back or into the ground. Looks like the Speed Canard setup without the muffler.

 

The tip of a long eze builders plane also showed diffuser holes drilled through. 

 

I’ve also seen on Nick Ugolini’s exhaust some scalloped tips that seem to have a positive effect. Maybe look at the tips of assault rifle barrels for more inspiration  on noise suppression methods and techniques. 

 

American operators don’t have to contend with anywhere near the noise issues of Europeans so its hard for us to understand the need for options. 

 

image

 

image

 

Izzy

(603)410-7277



On May 26, 2022, at 02:54, Michael Schrøder <michael@...> wrote:



Hi..

 

The testing is done at MTOW. You T/O and make a climb out using Vy. At the end of the runway the measuring equipment is located. You fly the "track" minimum 6 times and your noise has to be within certain limits.

 

The lenght of the RWY, the weather the whatever has to be within specific limits.

 

Br

 

Mike

 

Den ons. 25. maj 2022 kl. 13.14 skrev hnf.flyboy@... <hnf.flyboy@...>:

Is the testing done on the ground or as a flyby? Only things I can think of are a muffler, scalloping the exhaust tips of which there’s not much data or cutting the ends of the exhaust angling down from the top.

I’d like to know more about this as well. 


Sent from the all new AOL app for iOS

On Wednesday, May 25, 2022, 2:10 AM, Michael Schrøder <michael@...> wrote:

Hello Team... Have anyone invested time/brainpower in how to make our plane quieter from outside?.. I am in test flying and soon to undergo noise certification... (EU rules)

 

Best regards

 

Mike Schroeder

Denmark

# 0220, OY-CZY

 

 

 

Den søn. 22. maj 2022 kl. 19.32 skrev Yair Gil <goldcozy@...>:

Hello, 

In matter of noise reduction, I can’t explain, but was told by professional person, that engine cowling made out of Kevlar, affects noise reduction.

Yair

 

בתאריך יום ו׳, 14 בינו׳ 2022 ב-21:17 מאת <cozypilot@...>:

Hi all,

 Hi 

I have posted recently that I am on a campaign to make my Cozy quieter inside and have gotten some great comments.  I am using an iPhone audio spectrum analysis app called SpectrumView.  It is not cross platform but there are dozens of apps for Apple and Google phones.  I have not found one that works on both platforms. SpectrumView is fully usable for free with no ads and data can be captured by doing a screen shot.  For cheap you can upgrade to recording and many other measurement options.

 

I was curious if the data the app measures would be comparable/calibrated across different model iPhones and got a nice response from the developer; see below.

 

It would be interesting if we share measurements here on our forums.  I would suggest we try to do plots with similar conditions, that is, about 135 kn indicated in level flight and the phone 12” or so in front of the pilots face.

 

I hope this is of interest.

 

Del Schier

Cozy IV N197DL

Cannon Creek Airpark 15FL

 

 

 

 

 

 

From: Anil Alexander <anil@...>
Sent: Friday, January 14, 2022 8:38 AM
To: Oxford Wave Research Support <techsupport@...>
Cc: delsjunk@...
Subject: Re: SpectrumView question

 

Dear Mr Schier,

 

Thank you for getting in touch with us, and sorry for the delay in our response.

 

First of all, thank you for your positive comments about our software.- given your audio background, we are very glad you think it's good!

 

The Cozy IV looks amazing. I'm astonished about home-built airplanes in general, so very much in awe of what you and the support group are doing.  I happened to be at the Seattle Boeing museum of flight, looking at the Moult Taylor designs (https://www.museumofflight.org/aircraft/taylor-aerocar-iii) in amazement, thinking that the his dream of home planes for people had disappeared over the years. I can see it is alive and well!

 

Your work looks fascinating, and would certainly be interesting to us. We did some work with Airbus many years ago looking at specific frequencies in certain parts of their planes (https://oxfordwaveresearch.com/our-r-and-d/airbus -noise-profiling/) using Spectrumview.

 

Spectrumview takes the input from the iPhone's microphones and although the generally you will get similar results (same frequency range profiles), it will depend on the microphones, models and distance to the noise sources. One thing that we do not do is to measure the absolute noise like an SPL meter. One reason for this is as you say, different microphones may be calibrated differently. 


What would be useful to do however, is to take an average of several seconds of sound and look at the noise profile (see Spectrumview help for more details). Are there certain peaks that occur. Can they be correlated to specific things occuring (e.g. the motor spinning). 

 

We think this could be a fascinating case study, and would love to learn more. If you have anything public facing (blogpost,webpage, etc), do let us know, we would love to understand more.

 

Best regards

-Anil Alexander

 

On Thu, Jan 13, 2022 at 12:33 PM Oxford Wave Research Support <techsupport@...> wrote:

Dear Mr Schier,

 

Thank you for reaching out to us about SpectrumView, we are always keen to hear from our users. Many of our users apply SpectrumView to fascinating projects in various areas and it is great to hear about your project. A member from our team will respond to you shortly.

 

Kind regards,

 

Linda

 

Oxford Wave Research Support

www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663


Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

---------

From: <delsjunk@...>
Date: Sun, 9 Jan 2022 at 21:54
Subject: SpectrumView question

 

I am retired from the home and commercial audio business and think that your program is great but I haven’t found much use for it until recently.

I fly a 200 mph 4 seat homebuilt airplane called a Cozy IV. See: Cozy MK IV - Wikipedia It is terribly noisy and I have made a couple of measurements of my airplane, and recently, a similar one that seemed much quieter. A support group of hundreds of people that build and fly these aircraft are interested in sharing plots from your app to help find cabin noise reduction solutions.  We all must wear active noise cancelling headphones to make them bearable to fly in. see attached plots.

<<...>>

My question is; how much does the calibration change from one iPhone to another?  Is there much difference in the mic gain, response and sensitivity between iPhones?

Thanks in advance.

Del Schier

Cozy IV N197DL


 

--

--
Dr Anil Alexander
CEO, Oxford Wave Research Ltd

email: anil@...
phone: +44 1865 955250 (office)

phone: +447702157654 (mobile)
www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663

Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

--
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--

Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
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To view this discussion on the web visit https://groups.google.com/d/msgid/cozy_builders/CAJe-_p-fQM_mrhSDMCtGRQ_rohN%3DL_9S4vJid%3DsWL3gXtJyyyQ%40mail.gmail.com.


 

--

Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
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Izzy
 

Drag doesn’t matter if the government won’t let you fly it because it fails the noise test….again, Americans don’t get it. 



Izzy
(603)410-7277

On May 26, 2022, at 08:39, John Lambert <varieze@...> wrote:



Increased drag!

 

From: 'Izzy Briggs' via COZY Builders Mailing List [mailto:cozy_builders@...]
Sent: Thursday, May 26, 2022 7:34 AM
To: Michael Schrøder
Cc: hnf.flyboy@...; Yair Gil; Del Schier; Canard Forum; Canard Aviators; Cozy Group
Subject: Re: COZY: Making our airplanes quieter, A response from audio spectrum app developer.

 

I met a Defiant owner in  Norway last month that constructed the exhausts pointing straight up, curving around the cylinder  heads, which appears to help reduce noose by shooting the exhaust note up instead of back or into the ground. Looks like the Speed Canard setup without the muffler.

 

The tip of a long eze builders plane also showed diffuser holes drilled through. 

 

I’ve also seen on Nick Ugolini’s exhaust some scalloped tips that seem to have a positive effect. Maybe look at the tips of assault rifle barrels for more inspiration  on noise suppression methods and techniques. 

 

American operators don’t have to contend with anywhere near the noise issues of Europeans so its hard for us to understand the need for options. 

 

image001.jpg

 

image002.jpg

 

Izzy

(603)410-7277



On May 26, 2022, at 02:54, Michael Schrøder <michael@...> wrote:



Hi..

 

The testing is done at MTOW. You T/O and make a climb out using Vy. At the end of the runway the measuring equipment is located. You fly the "track" minimum 6 times and your noise has to be within certain limits.

 

The lenght of the RWY, the weather the whatever has to be within specific limits.

 

Br

 

Mike

 

Den ons. 25. maj 2022 kl. 13.14 skrev hnf.flyboy@... <hnf.flyboy@...>:

Is the testing done on the ground or as a flyby? Only things I can think of are a muffler, scalloping the exhaust tips of which there’s not much data or cutting the ends of the exhaust angling down from the top.

I’d like to know more about this as well. 


Sent from the all new AOL app for iOS

On Wednesday, May 25, 2022, 2:10 AM, Michael Schrøder <michael@...> wrote:

Hello Team... Have anyone invested time/brainpower in how to make our plane quieter from outside?.. I am in test flying and soon to undergo noise certification... (EU rules)

 

Best regards

 

Mike Schroeder

Denmark

# 0220, OY-CZY

 

 

 

Den søn. 22. maj 2022 kl. 19.32 skrev Yair Gil <goldcozy@...>:

Hello, 

In matter of noise reduction, I can’t explain, but was told by professional person, that engine cowling made out of Kevlar, affects noise reduction.

Yair

 

בתאריך יום ו׳, 14 בינו׳ 2022 ב-21:17 מאת <cozypilot@...>:

Hi all,

 Hi 

I have posted recently that I am on a campaign to make my Cozy quieter inside and have gotten some great comments.  I am using an iPhone audio spectrum analysis app called SpectrumView.  It is not cross platform but there are dozens of apps for Apple and Google phones.  I have not found one that works on both platforms. SpectrumView is fully usable for free with no ads and data can be captured by doing a screen shot.  For cheap you can upgrade to recording and many other measurement options.

 

I was curious if the data the app measures would be comparable/calibrated across different model iPhones and got a nice response from the developer; see below.

 

It would be interesting if we share measurements here on our forums.  I would suggest we try to do plots with similar conditions, that is, about 135 kn indicated in level flight and the phone 12” or so in front of the pilots face.

 

I hope this is of interest.

 

Del Schier

Cozy IV N197DL

Cannon Creek Airpark 15FL

 

 

 

 

 

 

From: Anil Alexander <anil@...>
Sent: Friday, January 14, 2022 8:38 AM
To: Oxford Wave Research Support <techsupport@...>
Cc: delsjunk@...
Subject: Re: SpectrumView question

 

Dear Mr Schier,

 

Thank you for getting in touch with us, and sorry for the delay in our response.

 

First of all, thank you for your positive comments about our software.- given your audio background, we are very glad you think it's good!

 

The Cozy IV looks amazing. I'm astonished about home-built airplanes in general, so very much in awe of what you and the support group are doing.  I happened to be at the Seattle Boeing museum of flight, looking at the Moult Taylor designs (https://www.museumofflight.org/aircraft/taylor-aerocar-iii) in amazement, thinking that the his dream of home planes for people had disappeared over the years. I can see it is alive and well!

 

Your work looks fascinating, and would certainly be interesting to us. We did some work with Airbus many years ago looking at specific frequencies in certain parts of their planes (https://oxfordwaveresearch.com/our-r-and-d/airbus -noise-profiling/) using Spectrumview.

 

Spectrumview takes the input from the iPhone's microphones and although the generally you will get similar results (same frequency range profiles), it will depend on the microphones, models and distance to the noise sources. One thing that we do not do is to measure the absolute noise like an SPL meter. One reason for this is as you say, different microphones may be calibrated differently. 


What would be useful to do however, is to take an average of several seconds of sound and look at the noise profile (see Spectrumview help for more details). Are there certain peaks that occur. Can they be correlated to specific things occuring (e.g. the motor spinning). 

 

We think this could be a fascinating case study, and would love to learn more. If you have anything public facing (blogpost,webpage, etc), do let us know, we would love to understand more.

 

Best regards

-Anil Alexander

 

On Thu, Jan 13, 2022 at 12:33 PM Oxford Wave Research Support <techsupport@...> wrote:

Dear Mr Schier,

 

Thank you for reaching out to us about SpectrumView, we are always keen to hear from our users. Many of our users apply SpectrumView to fascinating projects in various areas and it is great to hear about your project. A member from our team will respond to you shortly.

 

Kind regards,

 

Linda

 

Oxford Wave Research Support

www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663


Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

---------

From: <delsjunk@...>
Date: Sun, 9 Jan 2022 at 21:54
Subject: SpectrumView question

 

I am retired from the home and commercial audio business and think that your program is great but I haven’t found much use for it until recently.

I fly a 200 mph 4 seat homebuilt airplane called a Cozy IV. See: Cozy MK IV - Wikipedia It is terribly noisy and I have made a couple of measurements of my airplane, and recently, a similar one that seemed much quieter. A support group of hundreds of people that build and fly these aircraft are interested in sharing plots from your app to help find cabin noise reduction solutions.  We all must wear active noise cancelling headphones to make them bearable to fly in. see attached plots.

<<...>>

My question is; how much does the calibration change from one iPhone to another?  Is there much difference in the mic gain, response and sensitivity between iPhones?

Thanks in advance.

Del Schier

Cozy IV N197DL


 

--

--
Dr Anil Alexander
CEO, Oxford Wave Research Ltd

email: anil@...
phone: +44 1865 955250 (office)

phone: +447702157654 (mobile)
www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663

Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

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Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

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--

Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

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Andrew Anunson
 

If you fail the noise test, how difficult is it to reapply and test again?
Andrew Anunson
Cozy MKIV #1273

On May 26, 2022, at 8:59 AM, Izzy via groups.io <inbriggs@...> wrote:

Drag doesn’t matter if the government won’t let you fly it because it fails the noise test….again, Americans don’t get it. 



Izzy
(603)410-7277

On May 26, 2022, at 08:39, John Lambert <varieze@...> wrote:



Increased drag!

 

From: 'Izzy Briggs' via COZY Builders Mailing List [mailto:cozy_builders@...]
Sent: Thursday, May 26, 2022 7:34 AM
To: Michael Schrøder
Cc: hnf.flyboy@...; Yair Gil; Del Schier; Canard Forum; Canard Aviators; Cozy Group
Subject: Re: COZY: Making our airplanes quieter, A response from audio spectrum app developer.

 

I met a Defiant owner in  Norway last month that constructed the exhausts pointing straight up, curving around the cylinder  heads, which appears to help reduce noose by shooting the exhaust note up instead of back or into the ground. Looks like the Speed Canard setup without the muffler.

 

The tip of a long eze builders plane also showed diffuser holes drilled through. 

 

I’ve also seen on Nick Ugolini’s exhaust some scalloped tips that seem to have a positive effect. Maybe look at the tips of assault rifle barrels for more inspiration  on noise suppression methods and techniques. 

 

American operators don’t have to contend with anywhere near the noise issues of Europeans so its hard for us to understand the need for options. 

 

image001.jpg

 

image002.jpg

 

Izzy

(603)410-7277



On May 26, 2022, at 02:54, Michael Schrøder <michael@...> wrote:



Hi..

 

The testing is done at MTOW. You T/O and make a climb out using Vy. At the end of the runway the measuring equipment is located. You fly the "track" minimum 6 times and your noise has to be within certain limits.

 

The lenght of the RWY, the weather the whatever has to be within specific limits.

 

Br

 

Mike

 

Den ons. 25. maj 2022 kl. 13.14 skrev hnf.flyboy@... <hnf.flyboy@...>:

Is the testing done on the ground or as a flyby? Only things I can think of are a muffler, scalloping the exhaust tips of which there’s not much data or cutting the ends of the exhaust angling down from the top.

I’d like to know more about this as well. 


Sent from the all new AOL app for iOS

On Wednesday, May 25, 2022, 2:10 AM, Michael Schrøder <michael@...> wrote:

Hello Team... Have anyone invested time/brainpower in how to make our plane quieter from outside?.. I am in test flying and soon to undergo noise certification... (EU rules)

 

Best regards

 

Mike Schroeder

Denmark

# 0220, OY-CZY

 

 

 

Den søn. 22. maj 2022 kl. 19.32 skrev Yair Gil <goldcozy@...>:

Hello, 

In matter of noise reduction, I can’t explain, but was told by professional person, that engine cowling made out of Kevlar, affects noise reduction.

Yair

 

בתאריך יום ו׳, 14 בינו׳ 2022 ב-21:17 מאת <cozypilot@...>:

Hi all,

 Hi 

I have posted recently that I am on a campaign to make my Cozy quieter inside and have gotten some great comments.  I am using an iPhone audio spectrum analysis app called SpectrumView.  It is not cross platform but there are dozens of apps for Apple and Google phones.  I have not found one that works on both platforms. SpectrumView is fully usable for free with no ads and data can be captured by doing a screen shot.  For cheap you can upgrade to recording and many other measurement options.

 

I was curious if the data the app measures would be comparable/calibrated across different model iPhones and got a nice response from the developer; see below.

 

It would be interesting if we share measurements here on our forums.  I would suggest we try to do plots with similar conditions, that is, about 135 kn indicated in level flight and the phone 12” or so in front of the pilots face.

 

I hope this is of interest.

 

Del Schier

Cozy IV N197DL

Cannon Creek Airpark 15FL

 

 

 

 

 

 

From: Anil Alexander <anil@...>
Sent: Friday, January 14, 2022 8:38 AM
To: Oxford Wave Research Support <techsupport@...>
Cc: delsjunk@...
Subject: Re: SpectrumView question

 

Dear Mr Schier,

 

Thank you for getting in touch with us, and sorry for the delay in our response.

 

First of all, thank you for your positive comments about our software.- given your audio background, we are very glad you think it's good!

 

The Cozy IV looks amazing. I'm astonished about home-built airplanes in general, so very much in awe of what you and the support group are doing.  I happened to be at the Seattle Boeing museum of flight, looking at the Moult Taylor designs (https://www.museumofflight.org/aircraft/taylor-aerocar-iii) in amazement, thinking that the his dream of home planes for people had disappeared over the years. I can see it is alive and well!

 

Your work looks fascinating, and would certainly be interesting to us. We did some work with Airbus many years ago looking at specific frequencies in certain parts of their planes (https://oxfordwaveresearch.com/our-r-and-d/airbus -noise-profiling/) using Spectrumview.

 

Spectrumview takes the input from the iPhone's microphones and although the generally you will get similar results (same frequency range profiles), it will depend on the microphones, models and distance to the noise sources. One thing that we do not do is to measure the absolute noise like an SPL meter. One reason for this is as you say, different microphones may be calibrated differently. 


What would be useful to do however, is to take an average of several seconds of sound and look at the noise profile (see Spectrumview help for more details). Are there certain peaks that occur. Can they be correlated to specific things occuring (e.g. the motor spinning). 

 

We think this could be a fascinating case study, and would love to learn more. If you have anything public facing (blogpost,webpage, etc), do let us know, we would love to understand more.

 

Best regards

-Anil Alexander

 

On Thu, Jan 13, 2022 at 12:33 PM Oxford Wave Research Support <techsupport@...> wrote:

Dear Mr Schier,

 

Thank you for reaching out to us about SpectrumView, we are always keen to hear from our users. Many of our users apply SpectrumView to fascinating projects in various areas and it is great to hear about your project. A member from our team will respond to you shortly.

 

Kind regards,

 

Linda

 

Oxford Wave Research Support

www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663


Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

---------

From: <delsjunk@...>
Date: Sun, 9 Jan 2022 at 21:54
Subject: SpectrumView question

 

I am retired from the home and commercial audio business and think that your program is great but I haven’t found much use for it until recently.

I fly a 200 mph 4 seat homebuilt airplane called a Cozy IV. See: Cozy MK IV - Wikipedia It is terribly noisy and I have made a couple of measurements of my airplane, and recently, a similar one that seemed much quieter. A support group of hundreds of people that build and fly these aircraft are interested in sharing plots from your app to help find cabin noise reduction solutions.  We all must wear active noise cancelling headphones to make them bearable to fly in. see attached plots.

<<...>>

My question is; how much does the calibration change from one iPhone to another?  Is there much difference in the mic gain, response and sensitivity between iPhones?

Thanks in advance.

Del Schier

Cozy IV N197DL


 

--

--
Dr Anil Alexander
CEO, Oxford Wave Research Ltd

email: anil@...
phone: +44 1865 955250 (office)

phone: +447702157654 (mobile)
www.oxfordwaveresearch.com

Registered in England and Wales
Co. Reg. No. 07492663

Confidentiality Notice: This e-mail message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure, distribution or copying is prohibited. If you are not the intended recipient(s), please contact the sender by replying to this e-mail and destroy/delete all copies of this e-mail message

 

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--

Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

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--

Med Venlig Hilsen / Best regards

Michael Schrøder
In der Muhl 35
Jaegersburg
D-66424 Homburg
email: michael@...
Phone: +49 15153930189

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