F-35C nose gear issues

[talkitron]

"Pentagon establishes 'red team' to investigate F-35C nose gear issues, recommends possible redesign"

Didn't see this posted elsewhere; it is a pay site with a free trial until Trump's inauguration.

https://insidedefense.com/daily-news/pe ... s-possible

The Pentagon established a "red team" last September to investigate issues with the F-35C's nose gear and the team is recommending that if initial steps to fix the problem fail, the nose gear should be redesigned, Inside Defense has learned.

Last August, Navy fleet aviators from Strike Squadron-101 (VFA-101) were able to evaluate the F-35C catapult shot for the first time during at-sea testing.

"During a catapult launch the nose landing gear strut is compressed as the catapult pulls on the nose landing gear, with the hold back bar restraining the aircraft from forward movement due to engine thrust," according to a Dec. 28 Navy information paper viewed by Inside Defense. "Upon release of the hold back bar, the nose landing gear strut unloads and vertically oscillates as the aircraft accelerates towards take-off."

The motion is not only uncomfortable but the Helmet-Mounted Display and oxygen mask push back and up and down against the pilot's jaw. The jostling in the cockpit results in unreadable HMD during and immediately after launch, the paper reads.

[spazsinbad]

Thanks 'talkitron' - I'll put a link to your post in the HMDS thread also - I have had a free trial so I'm no longer eligible. BTW it is good to have TITLE / Date / Author to help search this forum for topic / info or whatever - anyway for above post:

Pentagon establishes 'red team' to investigate F-35C nose gear issues, recommends possible redesign
January 04, 2017 | Lee Hudson

[spazsinbad]

Way back in the dream time before the sea was created and there were only LAND catapults THIS was news back in 2011. So why was not this issue fixed before today? Must have been considered minor until VFA-101 got onboard to catapult?

Photo release: CF-1 hooked to test catapult for the first time
06 Apr 2011 PEO(JSF) Public Affairs NavAir

“PATUXENT RIVER, Md. - Navy F-35 flight test aircraft CF-1 approaches the TC-7 catapult at Naval Air Station Patuxent River March 22 [2011]. With U.S. Marine Corps test pilot Lt. Col. Matt "Opie" Taylor at the controls, CF-1 completed functional checks and performed the first test hookup of the F-35C to the catapult. The test team also investigated an issue discovered during a preliminary fit check with the launch bar where it did not lower far enough to engage flight deck hardware for the catapult hook up. That test resulted in an improvement made to the launch bar so it will have a greater range of motion. The overall ship compatibility test phase, including catapult launches, is scheduled to begin this year. Shipboard testing of the F-35C aboard a CVN-68 class aircraft carrier is scheduled to take place in 2013. The F-35C Navy variant & F-35B Marine Corps variant are undergoing test & evaluation at NAS Patuxent River in preparation for eventual delivery to the fleet.”

Source: http://www.navair.navy.mil/index.cfm?fu ... ry&id=4539

First TC-7 Catapult Launch
4 Nov 2011 CODE ONE LM PR

“A TC-7 steam catapult launched an F-35 for the first time with Navy Lt. Christopher Tabert at the controls. This launch was also the first F-35C catapult launch at NAS Patuxent River, Maryland.... Previous catapult launches used a TC-13 Mod 2 test steam catapult at Joint Base McGuire-Dix-Lakehurst, New Jersey.”

Source: https://www.f35.com/assets/uploads/down ... /f-35c.pdf [NO Workee Now so go below...]

http://www.codeonemagazine.com/gallery_ ... ry_style=3 [SCROLL DOWN BTM]

[talkitron]

Here is another quote from the original article. I don't want to give the impression that the F-35C nose landing gear will be redesigned; it will not.

The short-term actions are slated to begin in early 2017 and will take about two to six months to complete, according to the paper. The actions include implementing improved and standardized restraint procedures for pilots and flight testing later this month on the effects of a reduced RRHB release load. VFA-101 will evaluate both the restraint procedures and a reduced RRHB load during its next carrier qualification period in the spring, the paper reads.

In late 2017, medium-term actions ranging from six to 12 months to complete will begin. These include HMD symbology, nose landing gear modifications and pilot motion modeling. Regarding symbology, "Options are being considered that would simplify the information displayed to the pilot during and immediately after catapult launch, to make it easier for the pilot to interpret flight-critical data," the paper notes. One of the problems here is the contractor doesn't think there is enough time in the system design and development phase to demonstrate this in simulation, according to the paper.

Long-term actions would not begin until 2019 and would take 12 to 36 months to complete. These include RRHB geometry that would reduce compression of the nose gear strut before launch. This course of action may require ship modifications, according to the red team.

Another long-term action is a nose landing gear redesign. A redesign is not being pursued because of highly constrained design space.

"A redesign could incorporate all the benefits of the advanced modeling efforts, but is expected to require a multiyear effort to re-qualify a major redesign," according to the paper.

[talkitron]

Way back in the dream time before the sea was created and there were only LAND catapults THIS was news back in 2011. So why was not this issue fixed before today?

More quotes from the original article.

Documentation dating back to November 2014 reveals the developmental test community raised concerns about the F-35C catapult launch.

For example, a deficiency report issued in December 2015 that aggregated data from six previous reports acknowledged the catapult was suitable to continue developmental testing but would not be acceptable by fleet standards. VFA-101's at-sea testing last August was the first time fleet aviators could evaluate the catapult shot.

[talkitron]

Finally

F-35 Program Executive Officer Lt. Gen. Christopher Bogdan told reporters during a Dec. 19 roundtable at his office in Arlington, VA, "there's no doubt" his team has to find a solution to the nose gear.

However, he stressed, "the only time that is a problem with the C model is at very light gross weights. At medium weights and at heavy weights you don't see this problem at all."

Bogdan said his office is considering numerous short-term fixes, including changing the way pilots strap themselves into the aircraft and how they hold the straps.

"The long-term fix surely would be one that you would mechanically fix so that you don't have to make the pilots do any kind of special combinations," Bogdan said. "That fix is probably a couple of years off."

[spazsinbad]

Thanks 'talkitron'. Is that now the complete article? Can you post the article in complete form OR is it in the order you have posted? I could put it together but do not have answers to those questions. Thanks. Good to know the details now.

[talkitron]

Thanks 'talkitron'. Is that now the complete article? Can you post the article in complete form OR is it in the order you have posted? I could put it together but do not have answers to those questions. Thanks. Good to know the details now.

I feel bad about posting the entire article as it is a pay site. Everything I posted was in order but I did not post the entire thing.

[neptune]

https://www.yahoo.com/finance/news/most ... 13449.html

The most expensive F-35 variant has hit another major snag that could take years to fix

Alex Lockie,
Business Insider  

The Pentagon has established a "red team" to address considerable shortcomings with the F-35C, the carrier-based naval variant of the most expensive weapons project in history. The F-35, subject to cost overruns and delays throughout its production, reached an initial state of military readiness with its Air Force and Marine variants in 2016, but the Navy's variant lags behind in part due to an issue with its nose gear during catapult-assisted takeoffs from aircraft carriers, Inside Defense uncovered on Wednesday. Essentially the problem, detailed in a Navy report with data dating back to 2014, deals with rough takeoffs that hurt and disorient pilots at the critical moment when they're taking off from a carrier. The Pentagon's red team found the problem was due to several factors central to the plane's design, and recommended several fixes that will take several months to several years to fully fix. The report states that long term actions to address the problem will not take place until 2019, at which point they'll take 12-36 months to implement. Redesigns to the plane, as well as to carriers, may be necessary to fully address the problem.

A Pentagon deficiency report in 2015 stated that extreme movements in the cockpit during launch risked pilot health. One hundred and five pilots completing catapult launches rated their level of pain or discomfort on a scale of one to five. Of the 105, 74 pilots reported "moderate" pain or a 3, 18 pilots reported "severe" pain or a 4, and one pilot reported "severe pain that persists" after launching from an aircraft carrier. "The oscillations shake the pilot's head sufficiently to impair their ability to consistently read flight critical data, which poses a safety of flight risk," reads the report cited by Inside Defense. This pain, more than a mere inconvenience, threatens the ability of pilots to read flight-critical data as they perform the complicated task of launching from a moving platform at sea. Exacerbating the problem, some pilots locked down their harnesses to avoid jostling around during the launch, but this makes it more difficult for the pilot to eject, should they need to.

At a roundtable discussion in December, F-35 Program Executive Officer Lt. Gen. Christopher Bogdan assured reporters that F-35C takeoff problems only occur when the planes takeoff with low weight load outs, saying " you don't see this problem at all" when the plane is more laden with ordnance or fuel. A representative from Lockheed Martin told Business Insider that all the catapult launches they had monitored were successful.

The F-35C was the most expensive variant of the Joint Strike Fighter program for the most recent Low Rate Initial Production contract. The Navy currently operates aging F-18s, nine of which have crashed or majorly malfunctioned in the last six months of 2016. The Aviationist's David Cenciotti attributes this to the age of the planes.

Meanwhile, the Navy awaits the F-35C's groundbreaking capability as other world powers invest heavily in their naval and anti-ship capabilities. .. F-35 pilots have told Business Insider that the F-35s stealth characteristics make it absolutely vital to operating in heavily contested airspace like the South China Sea, the Baltics, and lately Syria. ..

...in previous discussions on this site, it was mentioned that this "CATASTROPHE" may be resolved by adding a simple restriction orifice in the hydraulics of the nose strut for the "Lite Load"...... much ado about nothing....

[spazsinbad]

I feel bad that you feel bad 'talkitron'. However the article is available to anyone who has not used the FOR FREE offer before. Used it a few years ago I did but not impressed enough to pay the horrendous subscription fee required. Can you PM me the entire article please? I will not post any more of it on this forum. Thanks. You could e-mail it also if you wish.

[spazsinbad]

WUT?! "...some pilots locked down their harnesses to avoid jostling around during the launch, but this makes it more difficult for the pilot to eject..." PLEASE EXPLAIN. In my FAA in the RAN years I never ejected but for entire duration I was tightly strapped in to every aircraft as this human unit could endure. I had permanent bruising on my shoulder blades from this 'torture'. Some others had similar if not worse experience. Some were hospitalized to have their spines stretched for a time (particularly from the really weird forward leaning MACCHI MB Mk4 ejection seat - that was also the worst one for me). STRAPPED IN TIGHT FOR CATAPULTING IN THE A4G!? You bet your sweet bippy. Boom 2 3 and OFF WE GO.........

[popcorn]

It would help if comparable figures for previous-gen aircraft were provided.


A Pentagon deficiency report in 2015 stated that extreme movements in the cockpit during launch risked pilot health. One hundred and five pilots completing catapult launches rated their level of pain or discomfort on a scale of one to five. Of the 105, 74 pilots reported "moderate" pain or a 3, 18 pilots reported "severe" pain or a 4, and one pilot reported "severe pain that persists" after launching from an aircraft carrier.

[spazsinbad]

We have videos on the forum showing the HORNET crowd bouncing up & down - mebbe they cannot breathe to complain?

[spazsinbad]

THIS RRHB above had me grasping for air: Repeatable Release Hold Back http://www.acronymattic.com/Repeatable- ... Back-(RRHB).html
&
RRHBB = Repeatable Release Hold Back Bar

[steve2267]

That Business Insider article by Alex Lockie was poorly written, at best.