How loud is the F-35?

[zerion]

Spaz your link doesnt work. Not sure why it's not linking the whole address. Tried posting one and same thing happens.

http://www.airforcemag.com/DRArchive/Pa ... -35-Noise-“Good-to-Go”.aspx

[smsgtmac]

It's because the Air Force Association, in their infinite(ly infinitesimal) 'wisdom' recently decided to put their content behind a paywall for members only. For you see, the AIr Force Association Mission:

"...to promote a dominant United States Air Force and a strong national defense, and to honor Airmen and our Air Force Heritage. To accomplish this, we:
EDUCATE the public on the critical need for unmatched aerospace power and a technically superior workforce to ensure U.S. national security.
ADVOCATE for aerospace power and STEM education.
SUPPORT the total Air Force family, and promote aerospace education."

... is somehow better implemented by hiding all of your 'message' away from the prying eyes of the general public?

P.S. Try looking at the 'cached' view in MSIE if you can. They haven't figured out how to hide that away....yet.

[spazsinbad]

Hmmmm.... agree about the 'association' being inscrutable - their bad - but anyway when the link worked I saw all of it; so ALL of it is excerpted on previous page. And a graphic just to be safe....

ttp://www.airforcemag.com/DRArchive/Pag ... -35-Noise-“Good-to-Go”.aspx

TIN Y URL of above (leadin' aich missing): http://tinyurl.com/ksa28h5

[zerion]

Thanks
I archive as much as I can for quick access in arguments.

[spazsinbad]

Noise testing on the F-35A and F-35B
31 Oct 2014 JPO/AFRL

"The F-35 Joint Program Office, in partnership with the Air Force Research Laboratory, conducted noise testing on the F-35A and F-35B in 2013, using production...

...Summary:
o All F-35 US Services and Partners are using the same noise data. However, the F-35 community noise contours will be different at many US and overseas installations due to differing regulations determining the calculation method, local takeoff and arrival profiles, terrain, and local environments.

o The community noise contours computed using the Sep 2013 production representative F-35A and F-35B noise data are essentially equal to or slightly smaller than the contours in recent F-35 Environmental Impact Statements developed using the 2008 F-35AA1 noise data.

o F-35C noise data is expected to be essentially equal to F-35A noise data except for low power approach conditions and high speed (>450 knots) conditions, where it is estimated to be slightly louder.

o The F-35 Joint Program Office is releasing noise data to our US Services, International Partners, and Foreign Military Sales customers to perform their Environmental Impact Assessments.

Source: http://www.jsf.mil/news/docs/20141031_F ... ummary.pdf (324Kb) Attached anyway....

"...The F-35A and F-35C engines are only different in that the F-35C has special salt corrosion prevention materials for aircraft carrier operations. The F-35B engine includes a swivel nozzle and lift fan for short takeoffs and vertical landings. All three variant engines have a maximum thrust of 43,000 lbs...."

[smsgtmac]

I can't describe how much I love this. The imaginary 'Noise' issue has been a central pillar in the Anti-F-35 crowd's strategy to kill off the F-35 because it is an 'issue' they thought they could really get the average citizen behind. It has been beaten to death in Vermont, where the 'Antis' (Socialists to NIMBYS) have tried every legal angle possible, and distorted data and truth beyond recognition in their arguments, trying to stop the Green Mountain Boys from getting their next airplane.

[spazsinbad]

Clarification on F-35 Noise
04 Nov 2014 AFA Mag'n

"F-35 Program Executive Officer Lt. Gen. Christopher Bogdan said an engine with the same decibel level of noise as another may be perceived as louder if the character of the noise has a higher or deeper pitched tone. During a press briefing on Oct. 30, Bogdan made an analogy to the F-4 Phantom (see F-35 Noise Good to Go). However, the F-35 engine noise study to which he referred did not compare the F-35’s sound to that of the F-4."

Source: http://www.airforcemag.com/DRArchive/Pa ... Noise.aspx

[popcorn]

The science should settle the noise non-issue. Won't be surprised if it does‘t for many.

[spazsinbad]

Possible development?

Keeping the noise down
Jeff Peters AEROSPACE AMERICA/DECEMBER 2014

"The Aeroacoustics Technical Committee addresses the noise produced by the motion of fluids and bodies in the atmosphere and the responses of humans and structures to this noise.

Aeroacoustics is a critical area in the development of aerospace products, as the demand for low noise remains important in both military and commercial applications. Controlling acoustic emissions at the source requires engineers to design for low noise from the start. Aeroacoustics research conducted in 2014 responded to this challenge, highlighted by progress made in understanding complex features in the jet plumes of tactical military aircraft and launch vehicles. Also noteworthy are recent improvements to aeroacoustic measurement systems and test facilities that provide more insight into noise source characterization of aerospace products.

An important area of research for military applications is noise reduction in supersonic exhaust. The objective is to mitigate noise-induced hearing loss and improve the safety of people operating near tactical aircraft. A team of engineers from Lockheed Martin, BAE Systems and the U.S. government continued the investigation of noise generated by all three variants of the F-35 fighter aircraft. Noise data was recorded in the near and far fields for static engine tests, conventional flight and short-takeoff/vertical-landing operations to characterize the external sound generated by the aircraft.

Researchers at Penn State University developed a novel jet noise reduction system for high-performance aircraft. The patented method injects “fluidic inserts” in the diverging section of a supersonic exhaust nozzle. The inserts generate streamwise vorticity in the plume, which enhances jet mixing and reduces broadband shock-associated noise. Early experiments resulted in a 4-decibel overall sound pressure level reduction in the peak noise radiation direction using moderate amounts of bypass air to generate the inserts Recent experiments demonstrated that the device also worked in the presence of forward flight. Larger-scale experiments are being planned at a General Electric facility, while small-scale tests and simulations continue at Penn State...."

Source: AEROSPACE AMERICA/DECEMBER 2014 Magazine

[spazsinbad]

Back on this thread about noise: viewtopic.php?f=56&t=10600&p=270955&hilit=hearing+damage#p270955
MOAR Mitigation by USN one hopes. "I CAN'T HEAR YOU"? What we have hear is a failure to communicate. God Bless You COOL HAND LUKE.

The Navy's new hearing protection: made-to-measure for every sailor
27 Mar 2023 USN PR

"NAVAL AIR WARFARE CENTER AIRCRAFT DIVISON, Patuxent River, Md.--Naval aviation now has a better solution to the Defense Department’s most reported injury, noise-induced hearing loss, thanks to research and development at the Naval Air Warfare Center Aircraft Division (NAWCAD).

Using digital-imaging technology, NAWCAD is developing a novel process to fit and provide service members custom hearing protection more efficiently and with less risk. The improved process is safer than today’s current process–which uses silicone injections–and will cut delivery time by at least 50%.

“Hearing damage is a readiness issue, but earns less attention because it is invisible and happens gradually over time,” said Lt. Cmdr. Kyle Shepard, NAWCAD’s resident audiologist and research lead. “Service members can compensate with hearing loss until one day they struggle to communicate from the cockpit or maintain situational awareness on the flight line or battlefield–we want to prevent that.”

Hearing damage affects at least 10% of the military according to data from the Navy and Marine Corps Public Health Center. Tinnitus and hearing loss is the U.S. military’s first and second most-reported disability. Using imaging scanners and 3D printers, the improved process would provide the opportunity to quickly fit any service member with custom hearing protection.... [more much at the jump]

...A 2006 study by NAWCAD showed that flight deck personnel typically do not insert foam earplugs correctly resulting in high risk for noise-induced hearing damage.

“We’ve seen that custom earplugs can provide improved consistency and sometimes better attenuation than standard earplugs because they conform to ear anatomy—they’re much easier to insert with less fit variability too,” said Shepard. “In addition, custom earplugs are an excellent option for aviators and ground crews using internal communication radios underneath of helmets or headsets.”..." [then the unexcruciating way it is dun]

Photo: "Lt. Cmdr. Kyle Shepard, resident audiologist and researcher at the Naval Air Warfare Center Aircraft Division, describes a simple process for the Navy to print custom ear plugs for its sailors using a digital ear scanner and 3D printer to Navy Surgeon General Rear Adm. Bruce Gillingham at Naval Air Station Patuxent River, Maryland. Noise induced hearing damage is the Department of Defense’s most reported injury. Shepard’s research validated the Navy could eventually fit any sailor for custom hearing protection the day they fit for their first uniform. (U.S. Navy photo by Todd Frantom)" https://www.navair.navy.mil/sites/g/fil ... 58-029.jpg (3.2Mb)

Source: https://www.navair.navy.mil/news/Navys- ... 32023-1605