The F-35’s Martin-Baker Ejection Seat

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archeman

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Unread post01 Oct 2015, 20:09

SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?


STOVL Weight Attack Team, or SWAT was offering bonus $$$ for those who came up with ideas to lower the 'B' weight

http://www.airspacemag.com/military-avi ... 83/?page=1

I wonder how much that same group would $$$ penalize you if you put forward that 'Add Lump of Weight' idea???
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Unread post01 Oct 2015, 20:19

neptune wrote:
SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?


Another perfectly good reason why "WOMEN SHOULD NOT BE ALLOWED TO BE FIGHTER PILOTS". they are too small. If you don't think so, ask a Marine! :poke: :D


Now that's trolling.
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Unread post01 Oct 2015, 20:21

neptune wrote:
SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?


Another perfectly good reason why "WOMEN SHOULD NOT BE ALLOWED TO BE FIGHTER PILOTS". they are too small. If you don't think so, ask a Marine! :poke: :D

RONG! Women will be well suited as F-35 'brainpower pilots' - MENTAL MIDGETS need not apply.
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Unread post01 Oct 2015, 20:38

On the women as pilots issue, the one pilot that has been temporary kept from flying is a man.

On the weight issue, it would be a temporary counterweight that would change based on who is the pilot. It (pilot + counterweight) would never exceed the max weight allowed for a pilot so SWAT issues do not come into play. In other words, if the pilot weighs 116 then add a 20lb weight to the headrest to total 136, the current minimum. If a pilot weighs more than 136, no counterweight is needed.
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Unread post01 Oct 2015, 22:46

spazsinbad wrote:
neptune wrote:
SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?


Another perfectly good reason why "WOMEN SHOULD NOT BE ALLOWED TO BE FIGHTER PILOTS". they are too small. If you don't think so, ask a Marine! :poke: :D

RONG! Women will be well suited as F-35 'brainpower pilots' - MENTAL MIDGETS need not apply.
Not seeing the problem here. Most American women haven't weighed 135 pounds since since age-12.
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Unread post02 Oct 2015, 11:27

Lookieloo is right;

The issue does not affect the first and only female F-35 pilot, Lt. Col. Christina Mau, 33rd Operations Group deputy commander, he noted.

Still in doubt whether this statement constitutes a faux pas on other fronts though... :wink:
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Unread post03 Oct 2015, 00:52

The 136lb minimum weight limit of the F-35's ejection seat is FYI, the exact same as the minimum weight limit for the F/A-18's NACES limit as well. The NACES seat nude body weight limits are 136 lb minimum and 213 lb maximum.
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Unread post03 Oct 2015, 02:38

archeman wrote:
SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?


STOVL Weight Attack Team, or SWAT was offering bonus $$$ for those who came up with ideas to lower the 'B' weight

http://www.airspacemag.com/military-avi ... 83/?page=1

I wonder how much that same group would $$$ penalize you if you put forward that 'Add Lump of Weight' idea???

Well, we are talking about pilots that are saving that weight anyway...
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Unread post03 Oct 2015, 03:16

I'll look for the Hornet/Super NACES info also so bear with - meanwhile here is some old info about the NACES ejection seat in the T-45A from 1999 PDF which is attached because the download URL is dangerous: AND... WTF is a CNO? This info is not in the PDF and may be elsewhere but WTF? :mrgreen: Chief of Naval Operations? :mrgreen: So I'll guess it is the even older ejection seat? :mrgreen:

Some good facts here such as:
The Ejection Site Fascinating Facts

"...At least one woman pilot has successfully ejected using an ACES II ejection seat. The exact number of female ejectees is changing as more women are involved in military aviation. Women are known to have ejected from a T-45A using a Mk. 14 NACES seat..."

Source: http://www.ejectionsite.com/ffacts.htm


https://www.cnatra.navy.mil/ebrief/docu ... TS%20(.167)/LINKS/NACES%20SEAT.PDF

T-45A NACES Ejection Seat 1999
"Seat performance, weight limits, and envelope for optimum ejection 1.3.5.1.3
A. Seat performance
1. +Gz Delivered a. Sustained - 12-18 +Gz acceleration
NOTE: These values are for the 98 percentile and 3 percentile aviators.
2. Human tolerances a. Sustained - 20-25 +Gz acceleration

3. “Zero-Zero” ejection
a. Ground level with no forward airspeed
b. Will travel approximately 155 ft in the vertical direction for the 98 percentile aviator and 200 ft for the 3 percentile aviator
c. Use “Zero-Zero” as a last resort only
B. Seat weight limits
1. The NACES nude body weight limits are 136 lb minimum and 213 lb maximum
2. The CNO nude body weight limits are 100 lb minimum and 235 lb maximum

NOTE: Being underweight puts one at increased risk of acceleration injury, and being overweight puts one at risk of inadequate ejection.

C. Envelope for optimum ejection
1. Altitude - above 2,000 ft
2. Attitude - straight and level (the NACES is NOT a vertical seeking seat)
3. Airspeed - 325 KIAS or below
NOTE: These values are for “optimum” ejection only. They are not required for a successful ejection."
Attachments
T-45A NACES SEAT 1999.pdf
(924 KiB) Downloaded 559 times
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post03 Oct 2015, 03:59

SupaDupaHornet Ejection Seat details (will attach NATOPS 24 PDF pages for just this part) from:
NATOPS FLIGHT MANUAL NAVY MODEL F/A-18E/F 165533 AND UP AIRCRAFT
15 Sep 2008 USN

"...17.1.1 Ejection Seat Restrictions. During ejection seat development and testing, the SJU-17(V) 1/A, 2/A, and 9/A NACES seats were qualified for use by aviators with nude weights from 136 to 213 pounds, while the SJU-17A (V)1/A, 2/A, and 9/A NACES seats were qualified for use by aviators with nude body weights from 136 to 245 pounds. The minimum and maximum nude body weights allowed by OPNAVINST 3710.7 Series for those on aviation duty are 100 pounds and 235 pounds, respectively.

Therefore, a gap exists between the ejection seat certified weight range and the weights of the current aviator population.

WARNING
• Operation of the ejection seat by personnel weighing less than the qualified minimum nude weight, or more than the maximum qualified weight (noted above), subjects the occupant to increased risk of injury.
• An increased risk of severe injury or death during parachute landing fall (PLF) exists with surface winds exceeding 25 knots. High surface winds contribute directly to total landing velocity. When time permits, select parachute steering and turn into the wind to reduce landing velocity.
• Pilots should be trained in additional ejection risks associated with JHMCS. Ejection with JHMCS may cause severe or fatal injury.

The ejection seat catapult was designed for the qualified weight range only. Ejection seat stability is directly related to occupant restraint. All occupants should be properly restrained in the seat by the torso harness for optimum performance and minimum injury risk. Inertial reel performance may be degraded for occupants outside of the certified weight range

17.1.1.1 Injury Risks - Nude Weight Less than 136 Pounds. Lighter weight occupants are subject to a higher risk of injury due to the following factors:

1. Excessive pull back during inertial reel retraction.
2. Poor positioning during ejection.
3. Greater acceleration during catapult firing.
4. Higher parachute opening shock during ejections near the upper end of Mode 1 (approaching 300 KCAS).
5. Seat instability during drogue deployment during ejections above 300 KCAS.

WARNING
Lighter weight aircrew have greater risk of neck injury during ejection while using the JHMCS configuration. Minimum nude aircrew weights authorized to fly with the JHMCS helmet system is 136 pounds. Aircrew weighing less than the authorized minimum nude weight are restricted from flying with the JHMCS helmet system...."

Source: http://info.publicintelligence.net/F18-EF-000.pdf (19.5Mb)
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Ejection Seat Data NACES F18-EF-000 NATOPS 2008 Super Hornet pp24.pdf
(1.44 MiB) Downloaded 499 times
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post03 Oct 2015, 04:37

Hornet NATOPS Sep 2008 NACES Ejection Seat details with a 39 PDF page extract attached.
NATOPS FLIGHT MANUAL NAVY MODEL F/A-18A/B/C/D 161353 AND UP AIRCRAFT
15 Sep 2008 USN

"Chapter 17 EJECTION
"...Whenever possible, ejection airspeed should be limited to a maximum of 400 KCAS when flying with the JHMCS helmet system.
WARNING
The JHMCS configuration can contribute to increased neck loads during ejection, particularly at moderate to high speeds. Generally, neck loads increase as ejection airspeeds increase and may cause severe or fatal injury. Aircrews should eject at the lowest possible airspeed to minimize neck and injury loads.
NOTE
Aircrew will brief system peculiarities and potential injury from out of position and high speed ejections prior to each flight when using A/A24A-56 JHMCS lightweight HGU-55 A/P helmet....

...During ejection seat development and testing, the following seats were qualified for the respective minimum and maximum nude weight ranges for aviators listed here: SJU-5/A, 6/A, and SJU-17(V) 1/A, 2/A, and 9/A seats - 136 lb to 213 lb. SJU-17A(V) 1/A, 2/A, and 9/A seats - 136 lb to 245 lb.

• Operation of the ejection seat by personnel weighing less than the qualified minimum nude weight or more than the maximum qualified weight (noted above) subjects the occupant to increased risk of injury.
• Aircrew should be trained in additional ejection risks associated with JHMCS. Ejection with JHMCS may cause severe or fatal injury.

17.1.1 General Injury Risks.
1. Ejection seat stability is directly related to occupant restraint. All occupants should be properly restrained in the seat by their torso harness for optimum performance and minimum injury risk.
2. Inertia reel performance may be degraded for occupants outside of the qualified weight range. Lighter occupants may be injured during retraction, and both light and heavy occupants may experience poor ejection positions, resulting in an increased risk of injury during ejection....

...17.1.2 Injury Risks For Lighter Weight Crewmembers.
1. The ejection seat catapult was designed for the ejection seat qualified weight range.
2. For SJU-5/A and 6/A seats only:
a. Occupants weighing less than 136 pounds are subject to a higher risk of injury on the ejection seat catapult due to greater accelerations.
b. Occupants weighing less than 136 pounds are at risk of parachute entanglement at low speeds.
c. Occupants weighing less than 136 pounds are at greater risk of injury due to seat instability before main parachute deployment.

3. For SJU-17(V)1/A, 2/A, and 9/A seats only:
a. Occupants weighing less than 136 pounds are subject to a higher risk of injury on the ejection seat catapult due to greater accelerations.
b. Occupants weighing less than 136 pounds are at risk of injury during ejections near the upper end of mode 1 (approaching 300 knots) due to high parachute opening shock.
c. Occupants weighing less than 136 pounds are at greater risk of injury during ejections above 300 knots due to instability during drogue deployment.
4. For SJU-17A(V)1/A, 2/A, and 9/A seats only:
a. Occupants weighing less than 100 pounds are subject to a higher risk of injury on the ejection seat catapult due to greater accelerations.
b. Occupants weighing less than 136 pounds are at risk of injury during ejections near the upper end of mode 1 (approaching 300 knots) due to high parachute opening shock.
c. Occupants weighing less than 136 pounds are at greater risk of injury during ejections above 300 knots due to seat instability during drogue deployment.
WARNING
Lighter weight aircrew have greater risk of neck injury during ejection while using the JHMCS configuration. Minimum nude aircrew weights authorized to fly with the JHMCS helmet system is 136 pounds. Aircrew weighing less than the authorized minimum nude weight are restricted from flying with the JHMCS helmet system...."

Source: https://info.publicintelligence.net/F18-ABCD-000.pdf (17Mb)
Attachments
NACES Ejection Seat Data F18-ABCD-000 Hornet NATOPS 2008 pp39.pdf
(1.59 MiB) Downloaded 512 times
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post04 Oct 2015, 21:09

Geebus - here comes the hammer - ritely or rongly. A LONG POST BEST READ AT SOURCE if one has not read the earlier.
F-35 Fatal Ejection Fear Riles Congress
04 Oct 2015 Lara Seligman

"WASHINGTON — Concern is mounting on Capitol Hill after recent tests revealed a lightweight F-35 pilot’s neck could snap when ejecting at certain speeds.

The fears focus on the Martin-Baker US16E ejection seat. During testing of the new Generation 3 helmet this summer, testers discovered the risk of fatal neck injury when a lighter pilot ejects during slower-speed flights, according to a source with knowledge of the program. Testers discovered the ejection snapped the necks of lighter-weight test dummies, the source said....

...Since the issue emerged, lawmakers have vowed to push for increased oversight of the F-35, with one congresswoman condemning the program for “malpractice.” Rep. Jackie Speier, ranking member of the House Armed Services Committee’s subcommittee on oversight and investigations, slammed the Pentagon for rushing tests to field the plane prematurely.

“We’re seeing these flight restrictions because the F-35’s ejector seats weren’t tested to the level they would be on a normal aircraft, and the Pentagon rushed to field them prematurely. This is yet another example of the kind of procurement malpractice we should be avoiding,” the California Democrat said in an email to Defense News last week.

Meanwhile, the chairman of the House Armed Services subcommittee on tactical air and land forces pledged to hold an oversight hearing on the issue.

“We're having an F-35 hearing scheduled for Oct. 21. I'm certain it will show up then,” Rep. Mike Turner, R-Ohio, said, noting that he was not previously aware of the ejection seat concern. “I am going to have an oversight hearing on this."...

...The ejection seat issue is not related to the new Generation 3 helmet, built by Rockwell Collins and delivered to the JPO in August, DellaVedova said. But a source with knowledge of the program said the added weight of the new helmet compared to the Gen 2 version aggravates the ejection seat issue.

A standard ejection is a two-stage event, according to Lockheed’s F-35 website. First, an explosive charge or rocket motor integrated with the seat breaches the windscreen canopy. Second, the seat and pilot are launched upward via a rail system through the opening at a jarring rate of 12-14 Gs.

In August, testers discovered that when a lighter pilot is ejecting, the Martin-Baker seat rotates forward a bit too much, according to the source. That forward motion combined with the force of the ejection proved too much for the lighter dummies, snapping their necks....

...“To be honest, it doesn’t affect us at all because all our pilots weigh above 136 pounds, and to my knowledge there is only one Air Force pilot that weighs less than that, at Eglin,” Matherne said in an Oct. 1 interview.

For at least one international partner, the new weight restriction is not a concern. None of Norway’s F-35 pilots beginning to train on the country's new jets at Luke Air Force Base, Arizona, are affected by the weight limit, according to Col. Jarle Nergård, program manager for operations with the Norwegian F-35 Program Office.

Since the Norwegian Air Force has even tighter weight restrictions on its current F-16 fleet, “there isn’t a single fighter pilot in the Norwegian Air Force that is affected” by the 136-pound restriction, Nergård told Defense News in an email.

Nergård also said discoveries like this are to be expected in a test program, and that the F-35 is meant to accommodate a greater range of pilot body types and weights than legacy fighter aircraft.

“The incredible amount of force involved once you have an ejection means that you are playing at the limits of human tolerance,” Nergård said. “As partners, we do support the interim actions by the US Air Force as they are directly affected by the issue. We all have the safety of our pilots as our No. 1 priority."...

...Martin-Baker could not be reached for comment, and Lockheed Martin referred questions to the JPO."

PHOTO: "A composite image of an F-35 ejection seat test conducted by Martin-Baker. (Photo: Martin-Baker)" http://www.gannett-cdn.com/-mm-/f5165ed ... FSTRIP.jpg


Source: http://www.defensenews.com/story/defens ... /73219260/
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F-35compositeTestEjectionMB.jpg
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post05 Oct 2015, 01:14

“We’re seeing these flight restrictions because the F-35’s ejector seats weren’t tested to the level they would be on a normal aircraft..."

Oh really? What's a normal aircraft in your experience Rep. Speier?

Some years ago (iirc 2001) NAVAIR issued a similar restriction on the seats in the Hornet, Harrier (and Prowler, I think). This action came after each had been in service for decades.
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Unread post05 Oct 2015, 01:28

SpudmanWP wrote:Why not simply add a counterweight near the headrest to shift the COG higher?

I was thinking the same thing but wouldn't that effectively result in lowering the upper threshold of 245lbs by the amount of the counterweight? Larger pilots would be excluded if that's the case.
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Unread post05 Oct 2015, 02:35

Only put in the counter weight for pilots that need it.

You should easily be able to design one that mounts with two tabs & two clamps.

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