New dutch F-35 noise study

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energo

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Unread post16 Mar 2009, 23:05

The dutch released a new study on F-35 noise levels today:

"According to the National Aerospace Laboratory (NLR), there is almost no perceptible difference between the JSF and the Saab Gripen NG. This is evident from a report published Monday by the NLR on the assessment of noise data from the two candidates for the succession of the current F-16. The difference in maximum noise level of the JSF and the F-16 is small (5 dB).

With MIL power, the maximum expected noise is 109 dB for the Saab Gripen NG and 110 dB for the JSF. With afterburner the values are respectively 114 dB and 115 dB. For the current Dutch F-16, the results are from 104 to 107 dB in MIL power and 111 to 114 dB with afterburner."


The study also notes that the F-35 is likely to use less afterburner and carry out longer sorties (ie. fewer take offs and landings) due to its improved operational radius.

Translated link:

http://translate.google.com/translate?p ... l=nl&tl=en

Orginal link: http://www.refdag.nl/artikel/1398197/JS ... errie.html


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Vipernice

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Unread post17 Mar 2009, 00:17

With respect to the research.. is that all of it? Or what Jack de Vlies decided to release?

Because it's interesting that the Dutch detected 110 Db noise for a milpower F-35 at 3300ft while the USAF found it to be 107 Db at 1000 ft.

Even seems a bit strange to measure at 1000 meters when the Americans used just 300 meters. And no measurements of takeoff, APU or approach noise ?

Study... I laugh.

The Eglin BRAC tests released officially and in several dozens of pages concluded that the F-35 would be far louder than F-15 for instance.
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geogen

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Unread post17 Mar 2009, 08:51

The study also notes that the F-35 is likely to use less afterburner and carry out longer sorties (ie. fewer take offs and landings) due to its improved operational radius.



Just curious: what is a usual training radius of a RNlAF Viper say fitted with 2x NL type external tanks? Maybe 600 miles? I may be wrong on this, but initial blk 3 F-35s will NOT be external-tanked? If that's the case, operational blk 4 F-35 could be externally tanked starting around what, 2018-19? The point being, for clarification sake: a clean F-35 radius would be perhaps 50 miles greater than noted F-16 example? Not exactly 'far fewer' take-off/landings per Viper?

That being said, 'DO NOT LIVE IN AN AIR BASE RESIDENTIAL AREA IF YOU DON'T LIKE NOISE'. Sheesh.
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jacarlsen

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Unread post17 Mar 2009, 09:17

We had a briefing from a pilot here at Kjeller and he said unofficially that the F-35 is as noisy in mil as the F-16 is in AB. Bigger engine = more noise. Then again it is the sound of freedom :-)
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Unread post17 Mar 2009, 09:30

http://www.jsfnieuws.nl/?p=417

Jsfnieuws who collect news about jsf in the Netherlands writes that the report is already heavily criticised. Not surprisingly most take my position that this is not a real independent study.

The argument that "The study also notes that the F-35 is likely to use less afterburner and carry out longer sorties (ie. fewer take offs and landings) due to its improved operational radius. " was also not made in the study but was made by the ministry and Jack De Vlies.

Just another attempt to fool the public and politicans to rush into a JSF contract.
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energo

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Unread post17 Mar 2009, 10:43

Vipernice wrote:http://www.jsfnieuws.nl/?p=417

Jsfnieuws who collect news about jsf in the Netherlands writes that the report is already heavily criticised. Not surprisingly most take my position that this is not a real independent study.


It would be helpful if you provided a source to this criticism.


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asiatrails

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Unread post18 Mar 2009, 04:26

A 5 db(A) change can be significant, the study leaves a lot of information out but take a look at this table:


Sound Level Change = 0db
Relative Loudness = 0
Acoustic Energy Loss = Reference


Sound Level Change = -3db
Relative Loudness = 50%
Acoustic Energy Loss = Perceptible Change


Sound Level Change = -10db
Relative Loudness = 90%
Acoustic Energy Loss = Half as loud


dB sound pressure levels are unweighted. dBA levels are "A" weighted to approximate the way the human ear hears. For example, a 100 dB level at 100 Hz will be perceived to have a loudness equal to only 80 dB at 1000 Hz. The dBA scale is based on a child's hearing and was originally documented based on actual hearing tests to characterize the human ear's relative response to noise.

A good primer on sound pressure (noise) and its effects can be found at:

http://www.sengpielaudio.com/TableOfSou ... Levels.htm
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Vipernice

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Unread post18 Mar 2009, 19:07

energo I posted the source.

Here's another one. The Dutch parliament just decided that the worthless noise readings the ministry of Jack de Vlies submitted is not enough and demand a full investigation on noise levels.

http://www.nd.nl/artikelen/2009/maart/1 ... lgers-f-16
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energo

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Unread post22 Mar 2009, 00:05

Vipernice wrote:energo I posted the source.

Here's another one. The Dutch parliament just decided that the worthless noise readings the ministry of Jack de Vlies submitted is not enough and demand a full investigation on noise levels.

http://www.nd.nl/artikelen/2009/maart/1 ... lgers-f-16


I couldn't find any critical review of the study at the source you mentioned. To my knowledge the full paper has not been released yet, as the above article implies. I could be wrong of course. Perhaps you could elaborate what you mean when you say that "the report is heavily criticised"?


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tgif

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Unread post25 Mar 2009, 12:25

The company who made the noise measurements of the Gripen Demo for Saab has done a review of the NLR report. Their verdict is quite harsh and as a professional in this area I can only agree. The NLR independency is questionable and the numbers are bent to suit the pro-JSF in the Netherlands.

The reports are found on JSF Nieuws.
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Vipernice

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Unread post25 Mar 2009, 22:22

Energo stop being a tool and read what the Dutch say. Specifically the parliamentarians and the environmental ministers of the affected cities. There's plenty of sources and further links on the 2 I provided.
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energo

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Unread post25 Mar 2009, 23:46

tgif wrote:The company who made the noise measurements of the Gripen Demo for Saab has done a review of the NLR report. Their verdict is quite harsh and as a professional in this area I can only agree. The NLR independency is questionable and the numbers are bent to suit the pro-JSF in the Netherlands.

The reports are found on JSF Nieuws.


As I'm still unable to find the full NLR report or any nonpartisan commentary it, perhaps you could provide a link? Unfourtunately my dutch is rather rusty these days.

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tgif

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Unread post27 Mar 2009, 17:16

energo wrote:
tgif wrote:The company who made the noise measurements of the Gripen Demo for Saab has done a review of the NLR report. Their verdict is quite harsh and as a professional in this area I can only agree. The NLR independency is questionable and the numbers are bent to suit the pro-JSF in the Netherlands.

The reports are found on JSF Nieuws.


As I'm still unable to find the full NLR report or any nonpartisan commentary it, perhaps you could provide a link? Unfourtunately my dutch is rather rusty these days.

B. Bolsøy
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My dutch is quite rusty as well, but knowing English and German together with your best friend Google makes it possible to get a grasp of the context.

The statement from Prof. Sohan Sarin is found here: http://www.jsfnieuws.nl/wp-content/A2Zo ... nSarin.pdf

The NLR report is found here (unfortunately only in Dutch): http://www.defensie.nl/_system/handlers ... 128790.pdf

Report regarding measurements on Gripen NG Demonstrator is found here:
http://www.jsfnieuws.nl/wp-content/A2Zound_JAS39NG.pdf

Unfortunately I haven't found the original F-35 measurements report from Edwards online.
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Unread post12 May 2009, 11:24

F-35 recording deafens Val-P meeting
May 11, 2009 - 9:36 PM

Webb compiled the data and determined that the noise level created by a landing F-35 measures at 105-106 dB compared with the F-16's 90 dB and F-15's 91 dB. According to his estimates, the average person would find the new fighter jet to be two to three times louder than the F-16.




http://www.nwfdailynews.com/news/webb-1 ... raiso.html
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Pilotasso

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Unread post12 May 2009, 13:02

Noise doubes in intensity with every extra 3db's. its measured in a logaritmic scale. ;)
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