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 Post subject: Q: "How do M-Series grenades work?"
PostPosted: Mon Mar 01, 2004 5:49 pm 
Got to thinking about the functionality of the grenades, and I'm a little confused :)

When the grenade is fired from the PR, it presumably explodes on impact. So is the impact supposed to depress the trigger under the cap to detonate? This seems a little random, unless the rifle is pointed dead on at a non-moving target.

If there is another impact detonator, I can't see why the grenade would have a manual detonator button that only allows the marine to blow himself up!

Any thoughts?
Edited by: [url=http://pub217.ezboard.com/bthealienslegacy.showUserPublicProfile?gid=williegoldman>Willie Goldman[/url] at: 4/16/04 11:41 pm


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 Post subject: Re: Grenades - how do they work?
PostPosted: Mon Mar 01, 2004 8:41 pm 
i think the tech book said something about a 3 second delay feature

but the grenade is fired like a bullet for pin point precession...so yeah it needs a trigger on the front....remember in the air duct gormen had to pop the caps off to press da button? made the red cap is stronger enough to survive minor stuff (and in reference to newt about to touch the m40 and hicks said "no, dangerous"
....you want a kid to handle live ordnance?)

ppl in/was in the army, when using live modern grenades...don't the fail safes on it only have their limits?


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 Post subject: Re: Grenades - how do they work?
PostPosted: Mon Mar 01, 2004 9:03 pm 
in the AVP 2 game i remember being able to bounce 'nades from the PR by aiming just a bit in front of your target. it was the best way to nade a group of charging alien warriors.
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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 5:53 am 
I did a bit of research using our modern day equivalent: the M203 grenade launcher.

The M203 HEDP fuse grenade round does not arm itself until it has traveled 15 to 40 meters; it then becomes live and explodes on impact. The round arms itself while spinning through the air. Once it has rotated enough times, it becomes live.

So lets say the M40 grenades stay safe until one of two things happen:

1- They are launched from the tube of a grenade launcher. At which time the round arms itself (or is armed by the GL) and detonates on impact.

2- They are armed manually by removing the safety cap, and depressing the arming fuse button. After which the round detonates after a three (four?) second delay.

So how does it arm itself? Well it could arm itself the same way the M203 round does: by rotation. However it is possible the round is armed by the grenade launcher: That is what the brass primer on the base of the grenade might be for. The round becomes live before it leaves the launch tube and explodes on impact.

As for manual use: With a three second delay, the round can be thrown by hand like a modern day hand grenade. If you watch the WS version of Aliens, you'll see that Gorman presses the grenade button, Vasquez and Gorman start "hugging" the grenade, and a couple of seconds later it explodes. In this case they used it to commit suicide, but under different circumstances (i.e. being outdoors) they could have thrown it like a hand grenade.

Of course the grenades are susceptible to detonation by overheating: otherwise Ripley would have had to push all the buttons on all the grenades of her bandoleer before throwing it into the Queen's nest.;)

Hope this helps.:)
Kevin
The Sarge's Site
[url=http://ca.photos.yahoo.com/bc/ssgtburton/lst?.dir=/Sarge%27s+Pics&.src=ph&.order=&.view=t
&.done=http%3a//ca.photos.yahoo.com/]Sarge's Pics[/url]

"Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They've got really short hair and they always go for the throat."


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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 7:34 am 
That explination sounds pretty right-on to me, Sarge. That's the way I figured them to work.

"Of course the grenades are susceptible to detonation by overheating: otherwise Ripley would have had to push all the buttons on all the grenades of her bandoleer before throwing it into the Queen's nest. "

That would work just like having shotgun shells have their primers "cook-off" and explode.




"You think the average stormtrooper knows how to install a toilet main?!? All they know is killin' and white uniforms." - Clerks


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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 9:45 am 
If I remember the details from my tech manual, twisting the trigger (not pressing it) would activate a 3-second delay. Pressing and releasing it would detonate immediately. Vasquez was trying to keep Gorman from taking his thumb off the trigger, at that point it was a 'dead man's switch'. The inertial fuses seem like the best explanation, rather than depressing the trigger upon impact. I always assumed it operated like a 40mm grenade, the primer (usually a large pistol primer) sets off the powder charge in the base of the casing which propels the warhead out of the weapon. I doubt it could be tied to the grenade's arming sequence. About those inertial fuses...they can arm as short as 5 meters. The main reason for them is to prevent a soldier who isn't paying attention from hitting a nearby object (tree, etc) and fragging himself and/or his buddies.
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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 2:30 pm 
Quote:
Quote: Vasquez was trying to keep Gorman from taking his thumb off the trigger, at that point it was a 'dead man's switch'.


I re-watched the movie just to see if I was wrong: I'm not. Gorman depresses the trigger. Now you have to watch carefully or have slow-mo on: just as Vasquez reaches out to grab his hand, Gorman releases the trigger; his thumb clearly comes off it. A split second later Vasquez grabs his hand. Four seconds pass and the grenade explodes.

I think the tech manual is having some creative licence. It doesn't make sense to have a weapon like a grenade without some kind of timed delay. Unless you were using it to set up a makeshift boobytrap (or rob a bank).;)

*EDIT* I just read the tech manual grenade section. Just like Matt said, the grenade "can be used like an ad hoc hand grenade by flipping of its plastic cap, and twisting the trigger clockwise; five seconds later the round will detonate. Care must be taken not to strike or depress the trigger, otherwise the grenade will go off immediately."

Well if that's the case, then Birdie's assumption that the grenade explodes after it strikes a target (depressing the arming trigger), must be correct.

I totally agree with birdie: this seems a little too random to be an effective way to arm the round. Is the plastic cap suppose to fall off in mid-air? Or maybe it breaks off on impact? If that's the case would it make an effective safety cap in the first place- For God's sake don't drop that grenade!! Do you have any clue how fragile that safety cap is!?!;)
Kevin
The Sarge's Site
[url=http://ca.photos.yahoo.com/bc/ssgtburton/lst?.dir=/Sarge%27s+Pics&.src=ph&.order=&.view=t
&.done=http%3a//ca.photos.yahoo.com/]Sarge's Pics[/url]

"Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They've got really short hair and they always go for the throat."
Edited by: [url=http://pub217.ezboard.com/bthealienslegacy.showUserPublicProfile?gid=ssgtburton>SSgt Burton[/url] at: 3/2/04 7:51 am


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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 5:00 pm 
You must bear in mind just how fast the grenade is going to snap through the cap and cause detonation ;)

Striking the cap on the bottom may also start the chemicals inside the grenade reating ready for the detonation at the depression og the trigger... :roll:


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 Post subject: Re: Grenades - how do they work?
PostPosted: Tue Mar 02, 2004 9:24 pm 
It would be really nice to see a hi res 'cross-section' view of an M40. I think one has been done before but, not sure. Seeing this may help. ;)
Tom

[url=http://www.m41a.com][img]http://www.m41a.com/z_temporary/octsig.jpg[/img]
[/url]


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 Post subject: Re: Grenades - how do they work?
PostPosted: Thu Mar 04, 2004 4:20 pm 
Here's the only cutaway cross-section picture I could find:

[img]http://www.trooperpx.com/pulse/Accessories/PulseRifleManual3.jpg[/img]

Original artwork by Derrick Baena.

*Picture will be removed upon request. No Copyright or Trademark infringement is intended.


Kevin
The Sarge's Site
[url=http://ca.photos.yahoo.com/bc/ssgtburton/lst?.dir=/Sarge%27s+Pics&.src=ph&.order=&.view=t
&.done=http%3a//ca.photos.yahoo.com/]Sarge's Pics[/url]

"Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They've got really short hair and they always go for the throat."


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 Post subject: Re: Grenades - how do they work?
PostPosted: Thu Mar 04, 2004 4:38 pm 
MOdern grenade launchers use magnetic programming of shells. Each shell has two conducting bands streching around its body. At the end of the GL's barrel, there are two similar bands. By running current throught the barrel's bands (which would have to be made out of loops of conducting wire) a magnetic field can be created. As the grenade passes out, its bands pick up the magnetic field from each strip, creating current on ITS bands. Thus, by alternating the barrel's fields in the period of a millisecond as the shell passes out of the barrel, the gun's computer can transmit data in the form of a biniary signal directly to the exiting shell. This is what allows the modern options of explosion before, inside, or after a selected target on the scope. New guns being developed have these features built into the barrel, and have the signals controlled by computers in the scope. Really cool stuff if you ask me.

This would be how the grenade would work, simply becuase mechanical detonation etc is too archaic. Also, rotation of a grenade cap for timing would never be used. I mean, imagine a soldier with shaky nerves who tries to rotate the cap in the field but accidentally pushes it instead. Anyone with shaky hands would immediately be killed.

Thats my two cents.

Brian


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 Post subject: Re: Grenades - how do they work?
PostPosted: Thu Mar 04, 2004 5:06 pm 
Quote:
Quote:Also, rotation of a grenade cap for timing would never be used. I mean, imagine a soldier with shaky nerves who tries to rotate the cap in the field but accidentally pushes it instead. Anyone with shaky hands would immediately be killed.


My thoughts exactly. With the type of system the Tech Manual describes, it would be too easy to kill yourself in the confusion and heat of battle. I think they really missed the boat on that one.
Kevin
The Sarge's Site
[url=http://ca.photos.yahoo.com/bc/ssgtburton/lst?.dir=/Sarge%27s+Pics&.src=ph&.order=&.view=t
&.done=http%3a//ca.photos.yahoo.com/]Sarge's Pics[/url]

"Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They've got really short hair and they always go for the throat."


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