Author Topic:  (Read 5645 times)

Offline Pancho

  • Trade Count: (0)
  • Master Sergeant
  • *****
  • Posts: 415
    • View Profile
(No subject)
« Reply #15 on: February 17, 2004, 10:13:48 AM »
WOW! That is fantastic!
« Last Edit: December 31, 1969, 05:00:00 PM by Pancho »
aka: Frankie Four Fingers

Offline Farslayer

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2103
    • View Profile
    • http://www.amsog.com
(No subject)
« Reply #16 on: February 17, 2004, 10:34:40 AM »
Holy Crap!
« Last Edit: December 31, 1969, 05:00:00 PM by Farslayer »
Benn

Offline Neepster

  • Trade Count: (0)
  • Corporal
  • ****
  • Posts: 61
    • View Profile
    • http://www.chezjones.net
(No subject)
« Reply #17 on: February 17, 2004, 11:45:19 AM »
<br /><blockquote id="quote"><font size="1" face="Verdana" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by azsarge</i>
<br /><blockquote id="quote"><font size="1" face="Verdana" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Basher</i>
<br />Man, the GAU-8 develops over 4 tons of recoil force!
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Now, I don't know if this is true or not (there is tons of false info in the civ world regarding military hardware), but I saw on an old episode of Discovery Channel's "WINGS" that the A-10 decelerates rapidly due to the "recoil" of the 30mm, even in a dive.  Interesting, even it it's false (which it most likely is).

Sounds like a load of "cool fun facts about military stuff!" BS to me, but does anyone know for SURE?

Vell?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Sure!  It's basic physics!  Firing a 0.3kg round of 30mm DU at 1067m/s is imparting an impulse to that round and (due to Newton's 3rd law) the gun of approximately 9.6 tons of force (rough calculation).  Firing a hundred or several hundred rounds of ammo through the gun is imparting an acceleration to the aircraft from the recoil force that adds up pretty fast.  

Each round would be between 4 and 9 meters/second^2 of acceleration (depending on the aircraft mass) directly opposite the vector of the round (i.e. opposite the direction of A-10 travel).  Assume the A-10 is going about 400mph or (179 m/s).  Since the GAU-8 Avenger fires a minimum of 30 rounds/second, yes, I can imagine that firing a sustained burst would seriously slow the plane down.  I don't know if it could make it literally STOP in the air (especially since the aircraft engines would still be trying to accelerate the plane), but it might.  It seems like firing that gun while flying would be like putting a retro rocket engine on the front of your plane.

Chris
« Last Edit: December 31, 1969, 05:00:00 PM by Neepster »
“There is always a danger that collectivism by stealth, the steady erosion of individual responsibility by intrusive government, may strangle freedom by degrees. This, too, requires eternal vigilance.â€￾ – Margaret Thatcher

Offline Legs

  • Trade Count: (0)
  • First Sergeant
  • *****
  • Posts: 496
    • View Profile
(No subject)
« Reply #18 on: February 17, 2004, 11:50:45 AM »
You know, they said the same thing about Stallone when First Blood came out.  "If anyone were to fire REAL ammo through an M60, it'd sit him on his keester..."  Blah, blah, blah.  And bull caca.  The gun weighs enough to counter the recoil.  We had one at the range I worked at and it was indeed fired one handed by one of the range masters.  Accuracy was ridiculous, yes, but he withstood the recoil just fine.  He said it was harder to hold the gun than to fire it.  Jesse Ventura was carrying something like 150 pounds in gun, pack, generator, etc...that wasn't going to go anywhere from the recoil of a .223, which is what they used.  And that model was a field modified minigun originally slated for Navy use by SEAL teams.  Don't know if it ever saw action that way, but that was the idea.  You can clearly see that when he is firing it, he's having to fight the rotary force of the spinning barrels to keep it "on target" but otherwise there is little recail to worry about.  Also, for you film buffs, movie blanks use TWICE the gunpowder of real ammo, so the boom is much bigger.  They do it for the greater muzzle flash on camera.
« Last Edit: December 31, 1969, 05:00:00 PM by Legs »
Molon labe
\"Zippo first.\"

Offline Harley

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2254
    • View Profile
(No subject)
« Reply #19 on: February 17, 2004, 12:41:59 PM »
I agree, although there is definitely a big difference between an M60 firing at 500rpm versus a minigun at 3000rpm.  And it was a 7.62 not a 5.56 that they used. http://www.motionpicturearmourer.com/minigun.htm

http://www.fast-rewind.com/predator.htm

About that infamous minigun...The first time Jesse tried to fire the M-134 he was nearly hurt (severely) as the expended brass was ejected upward, and hit him in the chest. Afterwords, he wore body armor and they rebuilt the "Furniture" (the grips used to hold the weapon) so that the weapon ejected downward. The weapon was also firing at such a rate, that even with blanks the recoil was so great that they needed to reduce the rate of fire even further than the usual half rate. The M-134 usually fires at a rate of 6000 Rounds Per Minute (yes, that is 100 rounds PER SECOND!) or a half rate of 3000 RPM, and even that was too much. They eventually settled on a lower fire rate. Of course, the M-134, or any RBC (Rotary Barrel Cannon sometimes called "Mini guns") are not hand fired weapons and the recoil is nearly unimaginable. The weapon has such recoil that it would tip an ATV over and you can see light trucks move under the recoil (at full fire rate)... And yes, the barrels truly do "whistle when the weapon runs dry... [Thanks to Paul Graham]
« Last Edit: December 31, 1969, 05:00:00 PM by Harley »
\"Just because you\'re paranoid, doesn\'t mean they\'re not out to get you!\"

\"Have Gun - Will Travel\"

Offline leakingpen

  • Trade Count: (0)
  • Master Sergeant
  • *****
  • Posts: 392
    • View Profile
(No subject)
« Reply #20 on: February 17, 2004, 12:45:01 PM »
id add that a lot of the recoil force is used in gas compression, the propeling gases taking most of the reaction, and energy being spent in a recompression, and side venting of gasses and using them to cycle the weapon also absorb a lot of the force. also, most large scale weapons like that are designed with various other recoil  killing methods, i dont know it this one is, but if it was designed for hand use, im pretty sure it would be. so simply multiplying bullet weight by muzzle velocity is not going to give you anywhere near an accurate count of recoil energy actually being felt by the user.  and you cant add up all the recoil from a set time frame and say thats how much the guy is feeling.  if hes standing and theres a force back on his body, hes absorbing it and deflecting a good deal into the ground, so the recoil doesnt add up like that.
« Last Edit: December 31, 1969, 05:00:00 PM by leakingpen »

Offline Harley

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2254
    • View Profile
(No subject)
« Reply #21 on: February 17, 2004, 01:23:28 PM »
Not sure where you were going with that.  Since a minigun doesn't use any of the spent gas to operate the mechanism, (electric motor does all the work) it's like firing a bolt action rifle.  All the recoil is absorbed through the gun directly to the shooter unlike a semiauto rifle where the action and recoil mechanism use that energy to unload and reload the weapon and felt recoil is much less.
« Last Edit: December 31, 1969, 05:00:00 PM by Harley »
\"Just because you\'re paranoid, doesn\'t mean they\'re not out to get you!\"

\"Have Gun - Will Travel\"

Offline Legs

  • Trade Count: (0)
  • First Sergeant
  • *****
  • Posts: 496
    • View Profile
(No subject)
« Reply #22 on: February 17, 2004, 02:01:47 PM »
I'll have to fine my source matierial now, but I am positive it was not a 7.62 that they used.  I have a big article packed away somewhere with Jesse showing a cheesy grin standing next to the armorer who was onsite.  I can't imagine the above info applying to reality, though.  I've fired off full auto M16s and AKs, and even at the end of a 30 round mag I have yet to take a step backwards.  So the rate of fire is doubled, or tripled, and the number of rounds goes to 500 per second...yes, I'll step backwards, but anyone who's fired a machine gun knows that there is a rythym that develops.  You aren't continually pushed rearward.  Just watch the clip of the lady shooting off the .30 cal at the Arizonastan shoot.  She wavers and steps back, then steps back into it, forward.  If the gun is MOUNTED, as it would be on an ATV, yes...it could flip it with a large enough caliber.  But humans have their own "buffer" system and it works very nicely.
« Last Edit: December 31, 1969, 05:00:00 PM by Legs »
Molon labe
\"Zippo first.\"

Offline Pancho

  • Trade Count: (0)
  • Master Sergeant
  • *****
  • Posts: 415
    • View Profile
(No subject)
« Reply #23 on: February 17, 2004, 02:07:22 PM »
In that clip, the rounds they were pulling out of the box looked much bigger than 7.62. But when they showed the vehicle coming toward the camera, and zoomed in on the gun (looking into the muzzles), it looked like a 7.62 to me....maybe BIG bullets for show?
« Last Edit: December 31, 1969, 05:00:00 PM by Pancho »
aka: Frankie Four Fingers

Offline Harley

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2254
    • View Profile
(No subject)
« Reply #24 on: February 17, 2004, 02:13:19 PM »
Kyle I'm going to debate you on this till you're blue in the face. [;)]  The same gun was used in Predator and Terminator, 7.62x51.

Frankie, we're talking about two different things here, the Jessie James minigun is a 7.62 like they said in the video clip, but it's not the same gun used in the movies.  I know this thread is starting to get confusing.
« Last Edit: December 31, 1969, 05:00:00 PM by Harley »
\"Just because you\'re paranoid, doesn\'t mean they\'re not out to get you!\"

\"Have Gun - Will Travel\"

Offline Pancho

  • Trade Count: (0)
  • Master Sergeant
  • *****
  • Posts: 415
    • View Profile
(No subject)
« Reply #25 on: February 17, 2004, 02:30:35 PM »
Confusion = death of a thread! LOL
« Last Edit: December 31, 1969, 05:00:00 PM by Pancho »
aka: Frankie Four Fingers

Offline Legs

  • Trade Count: (0)
  • First Sergeant
  • *****
  • Posts: 496
    • View Profile
(No subject)
« Reply #26 on: February 17, 2004, 04:26:19 PM »
As I cannot find my more-than-a-decade-old magazine with my source info, I'll concede for the sake of love and harmony.  Mostly love.  Still, they do overcharge movie blanks and it's the gunpowder, not the lead, that creates the punch.  Either way, he did physically stand there and fire the thing.  So did I, but they cut my part out.  Too much nudity already, or something like that...
« Last Edit: December 31, 1969, 05:00:00 PM by Legs »
Molon labe
\"Zippo first.\"

Offline TheCrow

  • Trade Count: (0)
  • Sergeant
  • *****
  • Posts: 170
    • View Profile
(No subject)
« Reply #27 on: February 17, 2004, 04:26:39 PM »
I'll just put it this way:

I was told that the gun used in Predator was an M214 6-Pac, chambered in 5.56mm (that is from my source who is a loader on helicopters).  They had been previously used as experimental field weapons and were man portable.  I have picked them up myself and they are not that heavy.  For the rest of the weight, 15kg of gun and 25kg of ammo is not that bad; it's only 88 lbs.  Also, a 33lbs gun would dampen a lot of recoil.  

I was in error about the cable in the pants leg; the barrels were not "cable driven", the cable was attached to a battery source, to power the gun, and hidden up his leg.  As for recoil, that one webpage shows 'peak recoil force' only, the lower the rate of fire, the lower the overall recoil.  

Besides, the webpage is inaccurate on other details, the M134 is called the GAU-2 (that's what I have loaded) and their ROF is 2000-6000 RPM, not 4000-6000.  The M61 has an ROF of 4000-7000+, not up to 6000.
« Last Edit: December 31, 1969, 05:00:00 PM by TheCrow »

Team ORION Squad Leader


Offline Harley

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2254
    • View Profile
(No subject)
« Reply #28 on: February 18, 2004, 11:21:21 AM »
<blockquote id="quote"><font size="1" face="Verdana" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Legs</i>
<br />Either way, he did physically stand there and fire the thing.  So did I, but they cut my part out.  Too much nudity already, or something like that...
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

For those of you that would like to see Kyle's deleted scenes you need to buy the director's cut version!
« Last Edit: December 31, 1969, 05:00:00 PM by Harley »
\"Just because you\'re paranoid, doesn\'t mean they\'re not out to get you!\"

\"Have Gun - Will Travel\"

Offline Harley

  • Trade Count: (0)
  • Major General
  • *****
  • Posts: 2254
    • View Profile
(No subject)
« Reply #29 on: February 18, 2004, 03:30:54 PM »
<blockquote id="quote"><font size="1" face="Verdana" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Pancho</i>
<br />In that clip, the rounds they were pulling out of the box looked much bigger than 7.62. But when they showed the vehicle coming toward the camera, and zoomed in on the gun (looking into the muzzles), it looked like a 7.62 to me....maybe BIG bullets for show?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I think you're right, after looking at it again I think those are .50 cal rounds.
« Last Edit: December 31, 1969, 05:00:00 PM by Harley »
\"Just because you\'re paranoid, doesn\'t mean they\'re not out to get you!\"

\"Have Gun - Will Travel\"