The F-35’s Martin-Baker Ejection Seat

spazsinbad · by **spazsinbad** » 06 Oct 2015, 01:41

'checksixx' You make your claim and I make mine. I go on the reports as stated - you made an unqualified claim earlier - which you have now qualified. Good on you.

count_to_10 · by **count_to_10** » 06 Oct 2015, 02:52

checksixx wrote:
spazsinbad wrote:So. Because two reports say this on page one of this thread 'it is the helmet'? For Fsake Puhleez.

It is, and it isn't. I can understand how you or anyone else would find it confusing. The seat has NO issues. The helmet has NO issues. Combined, with a light weight pilot, if the seat over rotates...it COULD snap the pilots neck due to the increased weight of the helmet over other standard helmets. The permanent fix will be a 'software' fix for the seat.

Cheers

Or, the problem exists for every other implementation of the seat, regardless of helmet, but the F-35 is the only aircraft they ever bothered checking for this problem.

quicksilver · by **quicksilver** » 06 Oct 2015, 02:58

Un-bleeping believeable.

What do you not understand about 'not due to the differences between Gen II and Gen III' ?

Why don't all of you experts on ejection seat matters go to the government with your good ideas. I'm sure they await with bated breath...

oldiaf · by **oldiaf** » 06 Oct 2015, 23:40

Hill AFB has no pilot with light weight : All our 5 F-35A pilots are above 136-pounds :-
http://www.standard.net/Military/2015/1 ... r-Hill-AFB

tritonprime · by **tritonprime** » 07 Oct 2015, 00:49

DELETED

spazsinbad · by **spazsinbad** » 07 Oct 2015, 01:00

It would be GOOD 'tritonprime' IF you would read threads / search the forum before posting OLD news articles about thread topics - thanks. This same article has already been posted on page 2 of this very thread earlier:

viewtopic.php?f=60&t=27447&p=304486&hilit=riles#p304486

checksixx · by **checksixx** » 13 Oct 2015, 18:21

spazsinbad wrote:'checksixx' You make your claim and I make mine. I go on the reports as stated - you made an unqualified claim earlier - which you have now qualified. Good on you.

Uhhh...okay...great....glad you feel better about yourself.... :roll:

checksixx · by **checksixx** » 13 Oct 2015, 18:24

quicksilver wrote:Un-bleeping believeable.

What do you not understand about 'not due to the differences between Gen II and Gen III' ?

Why don't all of you experts on ejection seat matters go to the government with your good ideas. I'm sure they await with bated breath...

Go ahead and read my post above there sport...and chill.

spazsinbad · by **spazsinbad** » 14 Oct 2015, 21:25

Nothing like official spokespersons saying one thing to be contradicted by DOTE & 'other' source 'experts' - newsies luv it eh. Nice zero/zero video though. I'll imagine the ACES 'potential alternate F-35 ejection seat' crowd are going to grab handles on this & pull hard. :mrgreen:

ONLY a few excerpts from a very long article are posted below. So best read it all at URL.

F-35's Heavier Helmet Complicates Ejection Risks
14 Oct 2015 Lara Seligman

"WASHINGTON — In the latest hurdle for the Pentagon's F-35 joint strike fighter, testers this summer discovered that a lightweight pilot's neck could snap during a low-speed ejection.

The Joint Program Office blamed the phenomenon on the jet's ejection seat, Martin-Baker's US16E. But interviews conducted by Defense News in recent weeks indicate the added weight and bulk of the new F-35 helmet complicates the problem. It is still unclear whether the blame rests squarely with the helmet, or the seat, or somewhere in between....

...During testing this summer with the Gen III helmet, testers discovered increased risk of injury when a lighter pilot ejects at low speeds, a spokesman for the Pentagon's director of operational test and evaluation confirmed to Defense News in a recent email. Testers found the ejection snapped the necks of lighter-weight test mannequins, according to a source with knowledge of the program.

The potentially fatal problem did not occur during previous tests with the slightly lighter Gen II helmets, according to the source.

The problem was discovered this summer after two slow-speed sled tests of the F-35 ejection system failed, according to the DOT&E spokesman. A July sled test of a 103-pound mannequin in July at 160 knots and an August sled test of a 136-pound mannequin at the same speed both failed. The tests were conducted using the Gen III helmet....

..."DOT&E is aware of the two slow-speed sled test failures of the F-35 ejection system in July and August this year with 103lb and 136lb mannequins, respectively, equipped with the new Generation III helmet system," spokesman Adrian J.T. Rankine-Galloway said in an Oct. 9 email. "The F-35 Program Office has determined pilots who weigh less than 136 lbs. are more susceptible to injury than heavier pilots as a result of seat design and the dynamics involved in the ejection sequence, and have restricted any pilots below 136 lbs. from flying the aircraft, regardless of helmet type."

The main physical difference between the helmets is that the Gen III system weighs 5.1 pounds, about six ounces more than the old Gen II helmet, according to the source. This weight increase is primarily due to improvements to the night-vision camera, including better sensors to fix problems with the system's resolution and sensitivity.

DellaVedova stressed that helmet weight was not a factor in the Aug. 27 decision to ground lightweight pilots.

"That was an ejection seat issue discovered during the parachute opening phase and was not related to the differences between the Gen II and Gen III helmets," DellaVedova said. "For lightweight pilots in a low speed ejection condition, there is a possibility the pilot could rotate to a position in the ejection sequence where the parachute opening shock could cause the head to rotate backward."

The Gen III helmet met the JPO's specifications before testing began, Nieuwsma stressed. The ejection problem was discovered during flight tests earlier this year, he said. Lockheed Martin suggested "system workarounds" that could alleviate the problem, for instance adding chin pads, but the JPO decided the best long-term solution was to remove weight from the helmet, he said.

A preliminary design review on the improved helmet is scheduled for December, DellaVedova said. Ideas to reduce helmet weight include the reduction of internal strapping material, as well as removing an external visor. The Gen III Light helmet will weigh about 4.67 pounds, he said.

In addition to designing a lighter helmet, the JPO is looking into two other fixes to reduce the potential for an increased risk of neck injury, DellaVedova said. First, the team is working on installing a switch on the seat for lightweight pilots that will delay deployment of the main parachute. Also, the program will mount a "head support panel," which is a fabric panel sewn between the parachute risers that will protect the pilot's head from moving backwards during the parachute opening. These two fixes will be introduced when the next upgrade of the ejection seat comes online near the end of 2016.

All three fixes will be fully implemented by summer 2017, DellaVedova noted.

But the JPO may not be able to find an easy solution, one expert warned.

The Physics of Ejection... [left all of this out so another reason to read long post at URL below]

...Martin-Baker does not appear to have any pitch control at low speeds. The UK-based company has not responded publicly since Defense News broke the story about the dangers to lightweight pilots earlier this month.

DellaVedova said the JPO and industry has a two-pronged approach to address the pitching problem. The proposed weight switch set for lightweight pilots will keep the drogue chute attached longer to further reduce the speed of the seat before the main parachute deploys. The head support panel, meanwhile, will prevent the potential hyper extension of the neck and protect the head, he said.

Martin-Baker is financing an upcoming ejection seat sled test that will test the head support panel, DellaVedova said.

A bulkier helmet, like the F-35's Gen III, increases the risk of neck injury during both phases of an ejection, because the forward center of gravity brings the pilot's head down. However, removing helmet weight will not solve the basic problem of misalignment of the pilot when the main parachute deploys, the expert said....

...The F-35 helmet is large even compared to today's average HMD. All the information pilots need to complete their missions is projected on the helmet's visor, rather than on a traditional HUD. The latest iteration of the helmet, Gen III, is wide from side-to-side and front-to-back, meaning that if a pilot's head is even slightly off center, a significant amount of weight is displaced.

If a pilot's head is off-center during the first phase of ejection, acceleration of the pilot and seat up the rail, serious neck and spine injuries can occur.

Martin-Baker's F-35 seat, it seems, attempts to fix this problem with airbags on either side of the pilot's head — the same airbags that aggravate the pitching phenomenon that occurs in the second phase of the ejection....

...For the F-35, the low-speed ejection problem is worst with the lightest pilots, from 103 pounds to 135 pounds, and lessens as aircrew weight increases, according to the expert. But the risk does not disappear above 136 pounds, the expert stressed. F-35 pilots above that weight could still experience serious and potentially fatal injury during a low-speed ejection...."

PHOTO: "A Martin-Baker F-35 ejection seat test. (Photo: Martin-Baker) http://www.gannett-cdn.com/-mm-/f5165ed ... orseat.jpg

Source: http://www.defensenews.com/story/breaki ... /73922710/

Dragon029 · by **Dragon029** » 14 Oct 2015, 23:24

They do point out however that the issues did not occur with the Gen II helmets.

Either way though, the fact that the issue with the parachute deployment and the heat snapping backwards is a bit of a surprise to me, and one which can therefore be resolved without making the helmet lighter (even though they intend on doing that); the fabric sheet between the risers in particular seems like a simple yet brilliant way of doing that.

Spaz, would you be able to do a slow-mo of the ejection and parachute deployment in this video from about 0:55 onwards? I'd do it myself, but I don't have the functionality of my desktop right now.