Chinese jet seat ejection cartridge


#1


#2

Dr. Schmitt,

Very interesting cartridge. Thank you for sharing!

I think that is the only cartridge I have seen with dual priming (and I assume the holes in the base are for alignment with the firing pins?). Makes sense with the application in mind. The dull “plunk” of a firing pin striking a dud primer would not be the sound an aviator would like to hear when attempting to discharge the CAD that cartridge is used in…

Are there other “dual primed” cartridges out there for this or other uses? Any old patents for this perhaps dating back to when priming was less than reliable in general?

Large pyrotechnic display shells (fireworks) typically use dual fuses for the burst charge but that adds little to the complexity of the shell and none to the firing tube.

Dave


#3

The Russians have a whole series of dual primed CADs (as this Chinese one here is a clone of).

The Germans had dual primed cases in WWII for torpedo starter cartridges and depth charge launchers. The latter were also used by the Russians after they studied German designs after 1945.


#4

[quote=“EOD”]The Russians have a whole series of dual primed CADs (as this Chinese one here is a clone of).

The Germans had dual primed cases in WWII for torpedo starter cartridges and depth charge launchers. The latter were also used by the Russians after they studied German designs after 1945.[/quote]

Can you post some images ?


#5

Here are some:

Your Chinese type from above (to the left, note it has same markings a given here) and a smaller one (about cal. 4 but different by 2 mm or so), My Chinese is weak but due to the “7” I assume it to be a clone of the Russian PK-7-T (according to Russian docs it should be). The holes in the base are for positioning the CAD in front of the breech face due to the 2 primers.

Here the Russian aircraft CAD “PK-3M-1” which might be identical to the one on the right in the Chinese doc. The Russians made several of these types with differing length and diameter - too much work to list them now. (note: the Chinese used also some original Russian ammo)

Here some Czech copies/improvements for Russian types ( I wonder if they are interchangeable, they kinda should but who knows):

Here the German torpedo starter (can’t find the photos I took):

Here the Russian depth charge launcher:

Note that all cases have some means for positioning them correctly in front of the breech face due to the 2 primers.

The German depth charge launcher case I messed up, it has only 1 primer.


#6

Neat, never really thought of how the seat was ejected!!! Do modern fighter aircraft use these too?


#7

One could consider the .44 Henry RF as being double-primed - at least the firing pin hit the rim on two sides for redundancy.

I think modern supersonic fighter aircraft use rocket propulsion for seat ejection.


#8

This cartridges are quite interesting, but absolutely not a novelty…as far as the Russian ejecting seats are involved. It could be interesting to give us the case dimensions but for the chines drawings), with, caselength, casemouth diameter, head diameter and rim diameter, as well as the primers size, so this rounds could be included in our databases.

The Russian systems include this kind of big bore twin-rimed launching cartridges, obviously evolved from the old Heinkel system of WW II German vintage, which was adopted by the French from 1947 on, as ejecting seat with "Vérin Heinkel"rounds, manufactured by the S.F.M., looking like brass-cased big shotshells (32 mm calibre). They were loaded with an heavy charge of balistite in hollow tubes, looking like heavy brown spaghettis, approx. 12 cm long…

The system was quite rough and gave accidents, so it was soon replaced by the British Martin-Baker seat, which gave satisfaction and is still in use, in more modern variations.

The reason of the dual priming is the obligation of a very strong safety to work the device, without any risk of failure resulting from non-ejection of crews.

The Martin-Baker devices (several “marks”) used several kind of diversely shaped “cartridges”, containg balistite, every set being composed of a main round, cylindrical, for the seat itself, two flat ones, of bigger diameter, as accessories, plus two other smaller rounds for the “drogue” ejecting the main parachute itself, a.s.o. Another cartridge was used for canopy ejection, but nothing to see with the “seat” rounds, even if supposed to work under the same timing.

As Sksvlad seems to be anxious to know, these ejections on the medical point of view, are responsible bad damages are to the pilot’s spine, resulting in a lost of several cms in the guy’s height, if he has the bad habit to eject more than three times…

Phil.


#9

Thanks to all. I would like to see more detail of the German torpedo cartridges.


#10

[quote=“DennisK”]One could consider the .44 Henry RF as being double-primed - at least the firing pin hit the rim on two sides for redundancy.

I think modern supersonic fighter aircraft use rocket propulsion for seat ejection.[/quote]

Dennis, would that not be a question of weapon design then?
The .22 lr. Voere 014 semi auto rifle had a bar shaped (fixed) firing pin on it’s bolt face hitting the rim on 2 spots when the breech went forward. So we could call the .22 lr. dual primed too?


#11

Double primed cartridge means 2 primers. Rimfires have one primer no matter how many times one hits it. There have been combination rim and centerfire cartridge designs which are double primed.