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Post by Barnsey on Mar 15, 2007 15:47:53 GMT 12
What happened to the replacement ejection seats that were allegedly bought for the A4 around 98?
I remember that the project was in full swing, with people being winched up the rails (slowly) to check clearance (not enough), and seats bought and paid for. As I remember, the seats were a replacement that had been developed for the A7 Corsair - also a user of the Escapac. The new seats had an adapter that bolted onto the existing seat rails, reducing knee clearance even further. It was my understanding the program was cancelled because the F16 was coming soon and the cost-benefit wasn't justified for the remaining life of the A4.
If the RNZAF did indeed pay for ~25 seats, where did they end up?
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Post by corsair67 on Mar 15, 2007 16:49:57 GMT 12
What was the reason for replacing the existing seats; were they unsafe or something?
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Post by phil on Mar 15, 2007 17:12:47 GMT 12
The seat was the Stencil SIIIS-3, if we did purchase them they never arrived.
Pete Munn had the most to do with the project, he even went over to the US. I know we had one seat here for trials, but the project was canned due to the F16 purchase. I'm not quite sure they ever solved the problem of clearance with the HUD? I remember a sign outside 75 S&S that was like the old playground sign 'You must be shorter than this to enter' It was about 4 feet from the ground! I think BJ was nearly short enough.
Corsair - the reason we were replacing the escapac IG-3 was becuase it was crap. It suffered from assymetric tumbling, basically tumbling in the vertical and horizontal axis at the same time. The human body does not cope with this at all well, and the US Navy had had a number of deaths from drowning becuase pilots had been so disorientated and/or injured during the otherwise succesful ejection that they had not been able to stop themselves drowning once they hit the water. I would hope that barnsey had read the same report on the escapac that the seat bay had, or did the air force not tell the knucks?
Also it was a bit rough on the pilot, being just one big kick in the arse from the rocket motor, unlike the relatively gradual acceleration of the Martin Baker seats.
Another problem was the man-seat seperation hardly ever worked as advertised. The Mk82 seperator rocket was mounted on the left hand shoulder of the seat, and was supposed to rotate the seat backwards and down away from the pilot, unfortunately being off center it also added a twisting motion, and in almost every ejection (except barnsey's, fortunately) the RSSK-8A survival kit did not seperate cleanly and ripped away.
Another problem was the parachute deployment method. The NES12M parachute used a balistic spreader. Basically the parachute lines were threaded through metal weights that surounded an explosive charge, the parachute streaming from the pack pulled the firing mechanism, and BANG, your parachute blew open. Quick, but not very user friendly.
I think that's probably enough to be going on with.
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Post by corsair67 on Mar 15, 2007 17:42:42 GMT 12
Oh my God - I can understand why they wanted to change.
Sounds like the designers were more concerned with getting the pilot out of the aircraft, than whether he was actually alive afterwards.
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Post by phil on Mar 15, 2007 17:46:24 GMT 12
Well it was probably ok for it's day, but MB consider a succesful ejection one where the pilot is uninjured, ecapac (MDD possibly?) consider getting out of the aircraft a succesful ejection.
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Post by corsair67 on Mar 15, 2007 17:51:43 GMT 12
Is it true that the amount of "g" a pilot is experiencing at ejection is just short of the amount of "g" that will kill a human?
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Post by Dave Homewood on Mar 15, 2007 17:55:15 GMT 12
From memory the Skyhawk seats were not 0/0 like the Macchi's MB 10, were they? Weren't they something like 0/70? (or am I thinking of the Blunties, long time ago)
Were the Stencil seats rated 0/0?
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Post by phil on Mar 15, 2007 18:00:33 GMT 12
The escapac seat was 0/0, as were the MK10s.
The blunty PB4s were 0/90. They had no rocket motor, only the gun, so needed the airspeed to ensure the chute inflated before hitting the ground.
The Stencil were also 0/0.
I think the escapac seats were about 18g for a very short time, the Mk10s were lower, 12g I think, but the acceleration was gradual (well as gradual as you can get in .45 of a second!). That made all the difference though.
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Post by corsair67 on Mar 15, 2007 18:12:33 GMT 12
18G - geez, no wonder some pilots suffered spinal compression.
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Post by Dave Homewood on Mar 15, 2007 19:35:48 GMT 12
Thanks Phil. As I said, it had been a while since thinking about those figures. It got a bit confusing when I was at 1TTS learning this stuff as the first Maachis arrived halfway through my course so we had to start learning extra stuff.
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Post by FlyNavy on Mar 15, 2007 20:15:49 GMT 12
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Post by phil on Mar 15, 2007 20:37:41 GMT 12
I belive our A4s were initially equiped with 1C3s, but they were changed to -G3s earlier than Kahu I believe. I think the main difference was the man/seat seperation, the -C3 used an inflating bladder behind the pilot, like an airbag, the -G3 had the rocket. I'm not sure what other differences there were.
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Post by FlyNavy on Mar 15, 2007 20:57:08 GMT 12
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Post by Calum on Mar 17, 2007 22:52:30 GMT 12
Well it was probably ok for it's day, but MB consider a succesful ejection one where the pilot is uninjured, ecapac (MDD possibly?) consider getting out of the aircraft a succesful ejection. Considering it was designed in the late 1950's, early 60's it was pretty good. IIRC it along just about everything else in the A-4 was designed in house by Douglas
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Glen T
Flight Lieutenant
Posts: 85
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Post by Glen T on Mar 19, 2007 22:32:54 GMT 12
Barnsey, The UPCO seats were removed from the A7's in AMARC (I believe Pete was at AMARC at that time..they had to remove the cacoon material to get them). The A7's had their 1G-3 seats replaced with the Stencil (UPCO - now Goodrich) seats as part of a modernisation program because of the Escapac unreliability in the A4, A7, + S3 Viking. Only the A7's were retrofitted. Stencil only qualified the SIIIS-3 type seat in a single seat A4 sled trials. They had not sled tested in a TA4 at the time the USN A4's were withdrawn from service, and therefore no T/A4 was modified. Therefore the RNZAF was going to have to pay for sled tests on a TA4 - we only had five Tbird frames and to sacrifice one of these for sled tests was a problem - that we didnot have to face in the end !!! ), The seats from AMARC's A7's were planned to be overhauled to zero life by UPCO before being sent to NZ for the retrofit. The new carts were also being looked at for ordering etc... one of the other main problems for the A/C was the Kahu wiring loom running under the seat area.... it prevented the seat from sitting an inch or thereabouts further down into the cockpit ..as well as the rails that would mount the seat to the existing MDD rails putting the seat and occupant an inch or thereabouts further forward ...hence the problems with long legs, and knees not being able to pass by the HUD without leaving some bits behind!!!! Mr Fred Guill who helped design the Rapac and Escapac series of seats visited OH to offer guidance in the retrofit.
I believe the seats had been purchased, but when the F16 deal was sorted, the Project was shelved, the seats - which I believe had not got to the factory - were sold back to ?? the USA.....UPCO ?? not sure....I have some records of this so might get some more detail later ...
We received the Escapacs as 1C-3, as Phil said with Bladder man seat separation.... in the mid 70's, they were all 'significantly' upgraded to 1G-3 state.... The seat was really only designed with carrier launch dangers parameters in mind ..there was no difference of seat operation from cat launch, to being below 14,000 feet at 400mph !! ballastic spreader would spread that chute open in an instant.... so occupant damage (injury) would be extremely possible!!! Fortunately all the RNZAF's Escapac ejections were within reasonable seat envelopes of operation, and all were good 'saves'. Despite several problems as Phil has said, with one courts of inquiry actually looking at re-modifiing the seats back to 1C-3 status !!!!!!!!!!!!!!!! Gee talk about lets think backwards, but at least they had discounted this option and went for the UPCO seat Project to replace it altogether...
Glen
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Post by Radialicious on Mar 23, 2007 23:01:35 GMT 12
A step backwards IMHO was the reversion in the CT4E to the webbing shoulder harness. After FLT LT Garrick Beats was killed in the CT4B crash in the alps in the 90's, one of the factors in his death was the harness. From the buckle, the webbing ran up over the Mae West, the pilots shoulders, a metre or so back to the equipment shelf and then around the locking/ adjustable recoil drum. This was nearly 2 metres of webbing that had considerable stretch and compaction on the reel in an accident. If the pilot was not careful to force the shoulder straps down into the Mae West, a lot of protection could be lost. After the accident, the RNZAF modified the harness into a steel cable that wound around the drum and terminated back into webbing just behind the pilots shoulders. It was only long enough to reach over the pilot and had a fraction of the stretch of the old one.
I was stunned when I saw the CT4E delivered to PTS/CFS with the old style webbing. Obviously the owners (PAC) didn't have to go down the modification process that the RNZAF did but I am suprised the RNZAF accepted this step backwards - afterall it is their pilots that have to fly them.
As an aside, the old 248 frame that the RNZAF had to beef up during the CT4B days had reverted back to the old thickness and sure enough had to be beefed up again when the 'E' started cracking up within its first year.
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Post by Dave Homewood on Mar 24, 2007 9:37:13 GMT 12
Isn't that crazy. You'd think that surely PAC would have all the mod data from users and incorporate it into future machines to prevent further problems.
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Post by madmac on Mar 24, 2007 20:20:27 GMT 12
From my understanding of the CT4 crash was that if you read the appropriate report (don't know which) covering this element the conclusions regarding the change to the seat belt bear no connection to the rest of the report. Its been suggested that the conclusion was required to be different from that intended by the report writer. The crash was unsurvivable ( you can only hit the ground so hard regardless of how you are attached to the airframe) the miracle is that one of them survived.
Seat belts are designed to stretch by about 50% to 100%. For an inertia reel it would be closer to the lower figure. The seat belts were changed to American scientific I think ( at $20,000 a pop) for very little gain.
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Post by skyhawkdon on Mar 26, 2007 12:42:36 GMT 12
I was on PTS 1996-1998 when the CT-4B's were swapped for the E models. We had just finished mod'ing all the B's with the new harness' and intercostal strengthening. I think the harnesses were ex Sioux and were in stock anyway so didn't cost anything. We were amazed that the new E model didn't have any of these mods. Because the E model's were leased and not owned by the RNZAF I think it was a case of take them as they were from Aeromotive. There were also problems with the radios/intercomm system not being compatable with the RNZAF helmets. It took several years for that to finally get fixed. In my humble opinion the MOD Project Officer(s) were out of their depth in terms of engineering and contract knowledge for the E model lease (and King Air). You saw it happen on just about every major Air Force project - GD pilots put in charge of projects with no experience in project management, contracts or engineering. I suspect nothing has changed and it is still going on today!
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Post by phil on Mar 30, 2007 16:35:00 GMT 12
Surely a GD pilot is capabable of anything? I thought they were empowered when they got their commision?
Or is it just the GD branch that think like this?
Actually in all fairness, these failings have been recognised. I think you will find the NH90 and TLUH project are being run very well.
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