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Posted: 12/28/2015 10:14:42 PM EST
[#1]
nvm
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Posted: 12/28/2015 10:14:42 PM EST
[#2]
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I'm definitely wrong about stuff all the time and the last time I touched a TFT was 2008 so I'd like to know the correct answer. Learning manual gunnery was actually pretty interesting as a gun-nut. People either loved it or hated it with a majority not caring for it. Quote HistoryQuoted:
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Five Requirements: Accurate Target Location Accurate Battery (Gun) Location Accurate Ammunition and Weapon Information Accurate Met (Weather) Info Accurate Computational Procedures Rotation of the Earth doesn't matter. Wind direction/speed and drift of the round due to the spinning of the round are taken into consideration. If you account for all 5 of the variables above you can be very accurate in regards to POI and TOT. Manually calculated gunnery can be accurate, computers make it easier. lol Instead of laughing tell us the science. Your screen name sez you know it. I'm definitely wrong about stuff all the time and the last time I touched a TFT was 2008 so I'd like to know the correct answer. Learning manual gunnery was actually pretty interesting as a gun-nut. People either loved it or hated it with a majority not caring for it. What does Table H of a TFT account for? The Ballistic Kernel also accounts for it. I also recommend digging into the details behind those 5 Requirements for Accurate Fire(no longer using "predicted"). JRTC puts out a decent 1 slider which shows the 17 subsets to use as a simple guide. |
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Posted: 12/28/2015 10:14:52 PM EST
[#3]
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The coriolis effect still applies in East-West shooting. It applies in every direction. In the Northern hemisphere, always aim left. In the Southern, always aim right. Quote HistoryQuoted:
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I just don't quite get it. I'll use simplified speeds to articulate what I'm not understanding. If you shoot with the rotation of the earth and the earths speed is 400mph, the bullets speed relative to the firearm is 200mph, the firearm is already traveling at 400mph. So you are at 400mph and fire, the bullet is now going 400mph+200mph. You're now at 600mph but the Earth is still rotating at 400mph so you subtract 400mph and you're back at 200mph relative to the Earth. If you shoot against the rotation the gun is traveling at -400mph. Shoot and you ad 200mph. You're now at -200mph but the Earth is moving towards the bullet at 400mph so you ad that and you're still at 200mph relative to the Earth. You don't quite get it compared to that video because that video is wrong and you are right. It makes no difference which direction you fire east/west it will go the same distance and take the same amount of time. Everything is moving in relation to the earth so the forces cancel as if there is no rotation. If we were talking north/south firing that's a different story (always aim left!). The coriolis effect still applies in East-West shooting. It applies in every direction. In the Northern hemisphere, always aim left. In the Southern, always aim right. You are not correct. If it applies to east/west, which direction do you aim? Why? You don't aim up or down because it doesn't effect it! |
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Posted: 12/28/2015 10:14:55 PM EST
[#4]
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lol Quote HistoryQuoted:
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Five Requirements: Accurate Target Location Accurate Battery (Gun) Location Accurate Ammunition and Weapon Information Accurate Met (Weather) Info Accurate Computational Procedures Rotation of the Earth doesn't matter. Wind direction/speed and drift of the round due to the spinning of the round are taken into consideration. If you account for all 5 of the variables above you can be very accurate in regards to POI and TOT. Manually calculated gunnery can be accurate, computers make it easier. lol I know right. I delight that someone flying the moniker 'FDC' is laughing at that post |
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Posted: 12/28/2015 10:15:11 PM EST
[#5]
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"close enough" is pretty quick... "inshallah" is even faster... Quote HistoryQuoted:
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What will take longer, manually computing that or getting the AFATDS up and running? "close enough" is pretty quick... "inshallah" is even faster... Maybe. I have honestly loved AFATDS since it converted to Windows five years ago. |
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Posted: 12/28/2015 10:15:54 PM EST
[#6]
the world is your treadmill
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Posted: 12/28/2015 10:16:37 PM EST
[#7]
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Unless the projectile exits the atmosphere it won't make a difference. |
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Posted: 12/28/2015 10:16:43 PM EST
[#8]
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Must be Army mortars. Go re-read your FM 6-40 Ch 3 section 3. Where you'll find your abbreviated list AND the list of Standard Deviations, which includes the rotation of the Earth. It is factored into manual and computational ballistics. The trigonometry related to the azimuth you are firing on and your time of flight are factored against their relation to the direction of Earth's rotation. It can be a significant offset in impact especially at longer ranges, since the surface of the Earth is moving about 1000mph at the equator. That's about 1500ft/sec. Time of flight for a standard HE shell can be as long as a minute. Firing with or against that rotation can make a huge difference. But since most combat arty is adjust fire, hey, who cares about first shot accuracy, amirite? Quote HistoryQuoted:
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Five Requirements: Accurate Target Location Accurate Battery (Gun) Location Accurate Ammunition and Weapon Information Accurate Met (Weather) Info Accurate Computational Procedures Rotation of the Earth doesn't matter. Wind direction/speed and drift of the round due to the spinning of the round are taken into consideration. If you account for all 5 of the variables above you can be very accurate in regards to POI and TOT. Manually calculated gunnery can be accurate, computers make it easier. Must be Army mortars. Go re-read your FM 6-40 Ch 3 section 3. Where you'll find your abbreviated list AND the list of Standard Deviations, which includes the rotation of the Earth. It is factored into manual and computational ballistics. The trigonometry related to the azimuth you are firing on and your time of flight are factored against their relation to the direction of Earth's rotation. It can be a significant offset in impact especially at longer ranges, since the surface of the Earth is moving about 1000mph at the equator. That's about 1500ft/sec. Time of flight for a standard HE shell can be as long as a minute. Firing with or against that rotation can make a huge difference. But since most combat arty is adjust fire, hey, who cares about first shot accuracy, amirite? Thank G-d, finally an Artilleryman. |
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Posted: 12/28/2015 10:20:24 PM EST
[#9]
I have seen the error of my ways and stand corrected
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Posted: 12/28/2015 10:23:15 PM EST
[#10]
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Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Quote HistoryQuoted:
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FA firing solutions don't account for it. <-- Was Field Artillery FDC (Fire Direction Control) 13D Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Anyone who is saying the Coriolis effect isn't a consideration in artillery and was in the 13 series didn't learn their job well. If we have to compensate for Coriolis with extreme long range in rifles, you better believe that it is a factor for artillery and mortars. I've called in a bunch of artillery and mortars, as I was in 3 different Scout Sniper Platoons. Of course, we didn't have to worry about Coriolis as observers, but I know they calculate it in the FDC. Coriolis also has to be taken into consideration no matter what direction you're shooting. It affects both elevation and windage. If you are shooting north to south or south to north, you will have a full value windage factor for Coriolis because where you were aiming has moved to the east. If you shoot east to west, your target is moving to the east in relation to your projectile's trajectory, so you need less elevation. The opposite is true when you shoot from west to east, because the target is moving away from the trajectory. Time of Flight is one factor in Coriolis, as is azimuth to target. In Extreme Long Range shooting, we get a registered shot and correct from there, but if there is time to calculate Coriolis, POI will be closer to the target. With indirect fires, the same can be accomplished with a correction, but since the distances are so much farther, especially with artillery, it's important to have an accurate first round register and not one that was fired without a Coriolis calc. I think FDC computers have had integral software that includes Coriolis for decades now, but I wasn't 13 series, so I'll defer to them. |
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Posted: 12/28/2015 10:25:46 PM EST
[#11]
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lol Quote HistoryQuoted:
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Five Requirements: Accurate Target Location Accurate Battery (Gun) Location Accurate Ammunition and Weapon Information Accurate Met (Weather) Info Accurate Computational Procedures Rotation of the Earth doesn't matter. Wind direction/speed and drift of the round due to the spinning of the round are taken into consideration. If you account for all 5 of the variables above you can be very accurate in regards to POI and TOT. Manually calculated gunnery can be accurate, computers make it easier. lol Double lol |
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Posted: 12/28/2015 10:27:30 PM EST
[#12]
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Flies farther in the direction of the rotation of earth. As observed from space. Actually it may depend on what point in the earths rotation we are in corrosponding to its orbit. If you take a fish tank inside a plane going 760mph and the fish swims in the direction the plane is flying at 5mph does the fish cause a sonic boom?  If the fish farts it will cause a sonic boom, yes. |
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Posted: 12/28/2015 10:29:45 PM EST
[#13]
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Anyone who is saying the Coriolis effect isn't a consideration in artillery and was in the 13 series didn't learn their job well. If we have to compensate for Coriolis with extreme long range in rifles, you better believe that it is a factor for artillery and mortars. I've called in a bunch of artillery and mortars, as I was in 3 different Scout Sniper Platoons. Of course, we didn't have to worry about Coriolis as observers, but I know they calculate it in the FDC. Coriolis also has to be taken into consideration no matter what direction you're shooting. It affects both elevation and windage. If you are shooting north to south or south to north, you will have a full value windage factor for Coriolis because where you were aiming has moved to the east. If you shoot east to west, your target is moving to the east in relation to your projectile's trajectory, so you need less elevation. The opposite is true when you shoot from west to east, because the target is moving away from the trajectory. Time of Flight is one factor in Coriolis, as is azimuth to target. In Extreme Long Range shooting, we get a registered shot and correct from there, but if there is time to calculate Coriolis, POI will be closer to the target. With indirect fires, the same can be accomplished with a correction, but since the distances are so much farther, especially with artillery, it's important to have an accurate first round register and not one that was fired without a Coriolis calc. I think FDC computers have had integral software that includes Coriolis for decades now, but I wasn't 13 series, so I'll defer to them. Quote HistoryQuoted:
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FA firing solutions don't account for it. <-- Was Field Artillery FDC (Fire Direction Control) 13D Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Anyone who is saying the Coriolis effect isn't a consideration in artillery and was in the 13 series didn't learn their job well. If we have to compensate for Coriolis with extreme long range in rifles, you better believe that it is a factor for artillery and mortars. I've called in a bunch of artillery and mortars, as I was in 3 different Scout Sniper Platoons. Of course, we didn't have to worry about Coriolis as observers, but I know they calculate it in the FDC. Coriolis also has to be taken into consideration no matter what direction you're shooting. It affects both elevation and windage. If you are shooting north to south or south to north, you will have a full value windage factor for Coriolis because where you were aiming has moved to the east. If you shoot east to west, your target is moving to the east in relation to your projectile's trajectory, so you need less elevation. The opposite is true when you shoot from west to east, because the target is moving away from the trajectory. Time of Flight is one factor in Coriolis, as is azimuth to target. In Extreme Long Range shooting, we get a registered shot and correct from there, but if there is time to calculate Coriolis, POI will be closer to the target. With indirect fires, the same can be accomplished with a correction, but since the distances are so much farther, especially with artillery, it's important to have an accurate first round register and not one that was fired without a Coriolis calc. I think FDC computers have had integral software that includes Coriolis for decades now, but I wasn't 13 series, so I'll defer to them. Except your target does not move in relation to the projectile. That's the point we are trying to make. If you're in a car going 60 and you throw the ball to your friend in the front seat does the ball go 60 plus the speed of earth? No. You are all traveling the same speed in reference to the earth (assuming you are travelling east/west). Those forces all cancel out, which is why there is no Coriolis effect on E/W shots. Front seat speed = 60 + earth speed Back seat speed = 60 + earth speed Ball = 60 + throw velocity + earth speed How is the target travelling towards the ball/projectile? |
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Posted: 12/28/2015 10:29:53 PM EST
[#14]
Here's a better one for you:
If a helicopter is sitting on top of a Merry Go Round, and the blades of the helicopter are turning in the opposite direction that the Merry Go Round is turning in, but at the same RPM, can the helicopter attain transitional lift or not? 
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Posted: 12/28/2015 10:31:41 PM EST
[#15]
Shooting a round away from earths rotation a round theoretically gained distance by earth moving out from under it during it's time of flight.
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Posted: 12/28/2015 10:31:58 PM EST
[#16]
Quote HistoryQuoted:
Anyone who is saying the Coriolis effect isn't a consideration in artillery and was in the 13 series didn't learn their job well. If we have to compensate for Coriolis with extreme long range in rifles, you better believe that it is a factor for artillery and mortars. I've called in a bunch of artillery and mortars, as I was in 3 different Scout Sniper Platoons. Of course, we didn't have to worry about Coriolis as observers, but I know they calculate it in the FDC. Coriolis also has to be taken into consideration no matter what direction you're shooting. It affects both elevation and windage. If you are shooting north to south or south to north, you will have a full value windage factor for Coriolis because where you were aiming has moved to the east. If you shoot east to west, your target is moving to the east in relation to your projectile's trajectory, so you need less elevation. The opposite is true when you shoot from west to east, because the target is moving away from the trajectory. Time of Flight is one factor in Coriolis, as is azimuth to target. In Extreme Long Range shooting, we get a registered shot and correct from there, but if there is time to calculate Coriolis, POI will be closer to the target. With indirect fires, the same can be accomplished with a correction, but since the distances are so much farther, especially with artillery, it's important to have an accurate first round register and not one that was fired without a Coriolis calc. I think FDC computers have had integral software that includes Coriolis for decades now, but I wasn't 13 series, so I'll defer to them. Quote HistoryQuoted:
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FA firing solutions don't account for it. <-- Was Field Artillery FDC (Fire Direction Control) 13D Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Anyone who is saying the Coriolis effect isn't a consideration in artillery and was in the 13 series didn't learn their job well. If we have to compensate for Coriolis with extreme long range in rifles, you better believe that it is a factor for artillery and mortars. I've called in a bunch of artillery and mortars, as I was in 3 different Scout Sniper Platoons. Of course, we didn't have to worry about Coriolis as observers, but I know they calculate it in the FDC. Coriolis also has to be taken into consideration no matter what direction you're shooting. It affects both elevation and windage. If you are shooting north to south or south to north, you will have a full value windage factor for Coriolis because where you were aiming has moved to the east. If you shoot east to west, your target is moving to the east in relation to your projectile's trajectory, so you need less elevation. The opposite is true when you shoot from west to east, because the target is moving away from the trajectory. Time of Flight is one factor in Coriolis, as is azimuth to target. In Extreme Long Range shooting, we get a registered shot and correct from there, but if there is time to calculate Coriolis, POI will be closer to the target. With indirect fires, the same can be accomplished with a correction, but since the distances are so much farther, especially with artillery, it's important to have an accurate first round register and not one that was fired without a Coriolis calc. I think FDC computers have had integral software that includes Coriolis for decades now, but I wasn't 13 series, so I'll defer to them. I still don't get it. The object might be moving east because of the earth's rotation but your starting velocity is equally affected. I could see having to adjust windage even when firing east/west due to the sphere shape of the Earth....maybe. Even then I'm not sure it would be a factor. I'm not saying you're wrong, I'm just saying I don't get it. |
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Posted: 12/28/2015 10:35:45 PM EST
[#17]
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I just don't quite get it. I'll use simplified speeds to articulate what I'm not understanding. If you shoot with the rotation of the earth and the earths speed is 400mph, the bullets speed relative to the firearm is 200mph, the firearm is already traveling at 400mph. So you are at 400mph and fire, the bullet is now going 400mph+200mph. You're now at 600mph but the Earth is still rotating at 400mph so you subtract 400mph and you're back at 200mph relative to the Earth. If you shoot against the rotation the gun is traveling at -400mph. Shoot and you ad 200mph. You're now at -200mph but the Earth is moving towards the bullet at 400mph so you ad that and you're still at 200mph relative to the Earth. Quote HistoryQuoted:
I just don't quite get it. I'll use simplified speeds to articulate what I'm not understanding. If you shoot with the rotation of the earth and the earths speed is 400mph, the bullets speed relative to the firearm is 200mph, the firearm is already traveling at 400mph. So you are at 400mph and fire, the bullet is now going 400mph+200mph. You're now at 600mph but the Earth is still rotating at 400mph so you subtract 400mph and you're back at 200mph relative to the Earth. If you shoot against the rotation the gun is traveling at -400mph. Shoot and you ad 200mph. You're now at -200mph but the Earth is moving towards the bullet at 400mph so you ad that and you're still at 200mph relative to the Earth. You're thinking in terms of 3 dimensional distance not a linear distance measured against the surface of the spherical surface of the earth. YOU ARE CORRECT if we are takling about distance traveled in 3 dimensional space. However some of us (not my post because I like being a smartass) are talking about apparent distance ameasured against the surface of the earth. |
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Posted: 12/28/2015 10:36:39 PM EST
[#18]
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Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Quote HistoryQuoted:
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FA firing solutions don't account for it. <-- Was Field Artillery FDC (Fire Direction Control) 13D Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Well I sure as shit don't recall ever accounting for it in any of the fire missions I conducted. Granted we were using AFATDS... Now that you mention it though I do remember something about quadrant of the earth in AIT... The units I was in never did manual other than for training as I was always in a heavy or rocket unit which pretty much exclusively use's AFATDS. Always wondered why light seemed to be the only ones that did manual. ETA: It just hit me when I re-read what you asked about the Christmas Tree.. fuck me, pass the crow please.  
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Posted: 12/28/2015 10:36:57 PM EST
[#19]
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As a Gunnery Instructor I wish I had a real keyboard. There's just too much fuck in this thread to type with my thumb. I'll make this simple. Take away every variable that must be compensated for except rotation of the Earth. No wind direction/speed, no air density, no humidity, no temperature, no centripetal drift of the projectile. No anything other than the rotation of the Earth. Fire a round perfectly straight up. When it comes back down and impacts, is it east or west of the point from which it was fired? There's your answer. That's not an answer 
Dumb it down a bit more please?
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Posted: 12/28/2015 10:43:20 PM EST
[#20]
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I delight that someone flying the moniker 'FDC' is laughing at that post I've forgotten too much about FDC shit, but I still remember doing manual METs for certification and remember sitting and watching a GYK 29 fire up and show what version of the NABK it was loading. Still have an old "Christmas Tree" and 6-40 somewhere in my stuff. |
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Posted: 12/28/2015 10:44:24 PM EST
[#21]
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That's not an answer
Dumb it down a bit more please? Quote HistoryQuoted:
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As a Gunnery Instructor I wish I had a real keyboard. There's just too much fuck in this thread to type with my thumb. I'll make this simple. Take away every variable that must be compensated for except rotation of the Earth. No wind direction/speed, no air density, no humidity, no temperature, no centripetal drift of the projectile. No anything other than the rotation of the Earth. Fire a round perfectly straight up. When it comes back down and impacts, is it east or west of the point from which it was fired? There's your answer. That's not an answer
Dumb it down a bit more please? I taught Gunnery to Second Lieutenants in the Field Artillery Officer Basic Course for two years. Giving them the answer only works until you ask the next question. Sometimes you have to put their hand on the light switch and give them a good shove. |
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Posted: 12/28/2015 10:46:51 PM EST
[#22]
Quote HistoryQuoted:
That's not an answer
Dumb it down a bit more please? Quote HistoryQuoted:
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As a Gunnery Instructor I wish I had a real keyboard. There's just too much fuck in this thread to type with my thumb. I'll make this simple. Take away every variable that must be compensated for except rotation of the Earth. No wind direction/speed, no air density, no humidity, no temperature, no centripetal drift of the projectile. No anything other than the rotation of the Earth. Fire a round perfectly straight up. When it comes back down and impacts, is it east or west of the point from which it was fired? There's your answer. That's not an answer
Dumb it down a bit more please? I think he is implying it would not fall straight down, which is incorrect
If there is no other forces acting on it, of course it would fall straight down. The bullet is moving at the speed of the earths rotation before, during and after it is shot. There is no reason to think it would drift if there are no other external forces acting upon it. You can't just say something happens without proof. If something is changing the initial velocity of the bullet (the speed of the earths rotation) what is it? |
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Posted: 12/28/2015 10:48:01 PM EST
[#23]
How big of a difference are we talking about here? Assume base bleed, max charge and really pushing the distance of the weapon system?
Couple of meters? Hundreds of meters? |
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Posted: 12/28/2015 10:48:05 PM EST
[#24]
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Maybe. I have honestly loved AFATDS since it converted to Windows five years ago. Quote HistoryQuoted:
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What will take longer, manually computing that or getting the AFATDS up and running? "close enough" is pretty quick... "inshallah" is even faster... Maybe. I have honestly loved AFATDS since it converted to Windows five years ago. I fucking HATED the AFATDS when it came out in the mid-to-late 90's. I was stuck in the BN S-2 for a DS FA BN for a year, so I got to work on that POS a lot. (I was a 13F.) Once a week, we'd pull them out of the conexes and set them up in the BN conference room for training. We'd spend the entire time from 0900 until 1200 just getting them set up and establish comms with each other. After lunch, we'd get about an hour to an hour and a half of training before we'd have to start breaking them down to put them away and make to 1SG's COB formation. As a result, very few people actually learned how to use it effectively, and even fewer became truly proficient with them. |
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Posted: 12/28/2015 10:49:42 PM EST
[#25]
is it on a treadmill?
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Posted: 12/28/2015 10:52:00 PM EST
[#26]
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Well I sure as shit don't recall ever accounting for it in any of the fire missions I conducted. Granted we were using AFATDS... Now that you mention it though I do remember something about quadrant of the earth in AIT... The units I was in never did manual other than for training as I was always in a heavy or rocket unit which pretty much exclusively use's AFATDS. Always wondered why light seemed to be the only ones that did manual. ETA: It just hit me when I re-read what you asked about the Christmas Tree.. fuck me, pass the crow please. Quote HistoryQuoted:
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FA firing solutions don't account for it. <-- Was Field Artillery FDC (Fire Direction Control) 13D Wrong. It absolutely does. Ever work a Christmas Tree? It's on it. Guess why firing data computers need to know the grid zone designator of where you are. It's so it can properly correct for the Earth's rotation. Well I sure as shit don't recall ever accounting for it in any of the fire missions I conducted. Granted we were using AFATDS... Now that you mention it though I do remember something about quadrant of the earth in AIT... The units I was in never did manual other than for training as I was always in a heavy or rocket unit which pretty much exclusively use's AFATDS. Always wondered why light seemed to be the only ones that did manual. ETA: It just hit me when I re-read what you asked about the Christmas Tree.. fuck me, pass the crow please. AFATDS was OK when it just did Tactical Fire Direction. Once they wanted it to do Technical Fire Direction as well, it failed. I remember PCSing and getting to my section and "why the fuck are there two computers in my truck". One was an AFATDS and the other was the BCS. With all the IPs cleared to just push it to the BCS, the AFATDS actually came in handy by showing the tactical picture in training. For example, receive a digital mission in training when you are shooting a couple different impact areas. See the target pop in the impact area 3200 out from your AOF, confirm with the chart, and give the guns a good warning order about the out of traverse mission. Team sport, FDC plays with guns and guns play with FDC-makes everything faster. |
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Posted: 12/28/2015 10:55:36 PM EST
[#27]
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I fucking HATED the AFATDS when it came out in the mid-to-late 90's. I was stuck in the BN S-2 for a DS FA BN for a year, so I got to work on that POS a lot. (I was a 13F.) Once a week, we'd pull them out of the conexes and set them up in the BN conference room for training. We'd spend the entire time from 0900 until 1200 just getting them set up and establish comms with each other. After lunch, we'd get about an hour to an hour and a half of training before we'd have to start breaking them down to put them away and make to 1SG's COB formation. As a result, very few people actually learned how to use it effectively, and even fewer became truly proficient with them. Quote HistoryQuoted:
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What will take longer, manually computing that or getting the AFATDS up and running? "close enough" is pretty quick... "inshallah" is even faster... Maybe. I have honestly loved AFATDS since it converted to Windows five years ago. I fucking HATED the AFATDS when it came out in the mid-to-late 90's. I was stuck in the BN S-2 for a DS FA BN for a year, so I got to work on that POS a lot. (I was a 13F.) Once a week, we'd pull them out of the conexes and set them up in the BN conference room for training. We'd spend the entire time from 0900 until 1200 just getting them set up and establish comms with each other. After lunch, we'd get about an hour to an hour and a half of training before we'd have to start breaking them down to put them away and make to 1SG's COB formation. As a result, very few people actually learned how to use it effectively, and even fewer became truly proficient with them. AFATDS is garbage for technical fire direction(read PLT and Btry level talking directly to howitzer sections). Still is even with Windows. Just too many options, and too many hang ups. Special munitions such as smoke especially. Windows does allow the Excel wizards to add all the fancy ammo tracking spreadsheets though. |
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Posted: 12/28/2015 10:56:10 PM EST
[#28]
The projectile is a gryo. In long range shooting, we commonly refer to gyroscopic stability, and even have spin stability calculators to work out optimal rate of twist for different projectiles. Berger has just such a program to calculate spin stability.
The projectile retains spin stability to itself, like a planetary body. Gravity still affects the projectile, just as gravity affects the moon, but the projectile shape, speed, and rotation help keep it in the air longer. If you were to shoot a projectile that wasn't spun, trajectory would be more subject to gravity. This is one of the things people take for granted in the era of the rifle or spun projectile. We just expect the magic, but a lot is actually going on because of spin stability. Coriolis is evidenced especially in north-south/south-north azimuths, because the earth is a sphere, not a cylinder. The equator travels faster than north or south latitudes, which means the firing position is going faster or slower than the target if they are north or south of each other. The east-west problem is Eötvös Effect. |
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Posted: 12/28/2015 11:04:01 PM EST
[#29]
If the Earths rotation were taken into account as some imply here we'd be flying round-the-world flights east-to-west instead of west-to-east as we do now, even taking into account prevailing winds.
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Posted: 12/28/2015 11:05:52 PM EST
[#30]
When I went thru FDC training at Sill, BCS was the new hot shit, the Army's whole class was with it. Our Marine FDC classes had just a few days familiarization with BCS at the end, it was still a couple years down the procurement pike for us. We were taught manual calculations, slide rules, TFTs and all. And use of the BUCS (HP Scientific calculator with a cannon system specific ballistics chip). And we did sweat the trigonometry calcs for Earth's rotation. Hell if I can remember it now. I didn't see a BCS again for years.
Still have my old 155mm slide rule. |
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Posted: 12/28/2015 11:07:44 PM EST
[#31]
Quote HistoryQuoted:
If the Earths rotation were taken into account as some imply here we'd be flying round-the-world flights east-to-west instead of west-to-east as we do now, even taking into account prevailing winds. Lol |
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Posted: 12/28/2015 11:08:05 PM EST
[#32]
eta quoted wrong post
varying charge weight and muzzle elevation, like any range solution. The rotation calc is a correction factor, just as is wear on the tube, deviations from standard shell weight, winds aloft, etc. |
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Posted: 12/28/2015 11:10:22 PM EST
[#33]
Eötvös Effect
In the early 1900s a German team from the Institute of Geodesy in Potsdam carried out gravity measurements on moving ships in the Atlantic, Indian and Pacific Oceans. While studying their results the Hungarian nobleman and physicist Lorand Eötvös noticed that the readings were lower when the boat moved eastwards, higher when it moved westward. He identified this as primarily a consequence of the rotation of the Earth. In 1908 new measurements were made in the Black Sea on two ships, one moving eastward and one westward. The results substantiated Eötvös' claim. Since then geodesists use the following formula to correct for velocity relative to the Earth during a measurement run. |
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Posted: 12/28/2015 11:10:42 PM EST
[#34]
Quote HistoryQuoted:
If the Earths rotation were taken into account as some imply here we'd be flying round-the-world flights east-to-west instead of west-to-east as we do now, even taking into account prevailing winds. Quote HistoryQuoted:
If the Earths rotation were taken into account as some imply here we'd be flying round-the-world flights east-to-west instead of west-to-east as we do now, even taking into account prevailing winds. Here you go... From the linked manual: e. Deviations From Standard Conditions. Firing tables are based on actual firings of a piece and its ammunition correlated to a set of standard conditions. Actual firing conditions, however, will never equate to standard conditions. These deviations from standard conditions, if not corrected for when computing firing data will cause the projectile to impact at a point other than the desired location. Corrections for nonstandard conditions are made to improve accuracy.
(1) Range effects. Some of the deviations from standard conditions affecting range are: ?Muzzle velocity. ?Projectile weight. ?Range wind. ?Air temperature. ?Air density. ?Rotation of the earth. It's absurd that you think you know more about field artillery gunnery than the U.S. Army Field Artillery School. |
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Posted: 12/28/2015 11:11:42 PM EST
[#35]
Quote HistoryQuoted:
Spraying the nose of the round with Teflon will increase max range by 1/2 - 1 km. It's the advanced Mohican silk technique. |
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Posted: 12/28/2015 11:20:47 PM EST
[#36]
My dad gave a physics lecture recently discussing a German artillery officer from the Great War who developed/discovered a field of physics that has long been overlooked/forgotten by the 20th Century, that explains a lot of what people have been looking for with relativity, that was under our noses the whole time.
He calculated the orbital trajectory of the moon one time on pad and paper just for fun, after being forced away from the computer (installed the batteries in backwards on the keyboard). Aerospace engineer, mathematician, and theoretical physicist. I lost count of how many keys, wedding bands, and checkbooks he lost over the years. |
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Posted: 12/28/2015 11:21:13 PM EST
[#37]
DAMN IT, I'm pissed at myself now.
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Posted: 12/28/2015 11:21:54 PM EST
[#38]
I give oldarmy benefit of a doubt. There's a whole generation of arty men that know little more than an azimuth painted on the wall of a gun pit. The finer nuances weren't important and likely weren't even taught. even though they've been in the manuals for generations. I'm sure the same's been true in this last war. Just watch a few of those mortar pit fight vids from AFG, I sure don't see a plotting table in use. (then again the FDC guys are the slightly smarter ones, so they're probably hunkered down somewhere relatively safer)
All that shit got codified after WWII, and a lot of goats were staked out and blasted to hell to formulate the calculated fire effects in the Tactical Fire Table (TFT) books. TRADOC / FM6-40 has been making things complicated for a long time. And now that it is all computerized, nobody ever sees that Earth rotation correction. But it's programmed n there. |
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Posted: 12/28/2015 11:22:34 PM EST
[#39]
Are we talking real mans artillery? The kind you tow?
Or are we talking that gay rocket artillery? Or the Trannie SP (like having your own treadmill) heavy artillery? |
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Posted: 12/28/2015 11:25:16 PM EST
[#40]
Quote HistoryQuoted:
I give oldarmy benefit of a doubt. There's a whole generation of arty men that know little more than an azimuth painted on the wall of a gun pit. The finer nuances weren't important and likely weren't even taught. even though they've been in the manuals for generations. I'm sure the same's been true in this last war. Just watch a few of those mortar pit fight vids from AFG, I sure don't see a plotting table in use. (then again the FDC guys are the slightly smarter ones, so they're probably hunkered down somewhere relatively safer) All that shit got codified after WWII, and a lot of goats were staked out and blasted to hell to formulate the calculated fire effects in the Tactical Fire Table (TFT) books. TRADOC / FM6-40 has been making things complicated for a long time. And now that it is all computerized, nobody ever sees that Earth rotation correction. But it's programmed n there. The golden era of artillery science as it applies to calculated trajectory was pioneered by the Germans in The Great War of 1914-1918. |
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Posted: 12/28/2015 11:36:22 PM EST
[#41]
Quote HistoryQuoted:
Are we talking real mans artillery? The kind you tow? Or are we talking that gay rocket artillery? Or the Trannie SP (like having your own treadmill) heavy artillery? There's two kinds of Artillerymen: Cannoneers and Rocket Queers. :) 
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Posted: 12/28/2015 11:53:56 PM EST
[#42]
oh great, another GD physics thread.
here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k The projectile sitting in the chamber of the gun is motionless in relation to the chamber, barrel, etc. If the muzzle velocity of the projectile is 2,800 fps, the muzzle velocity is 2,800 fps regardless of the aircraft velocity. Show me an equation that demonstrates a .50 cal projectile, or any other, gains an additional 2,000 fps by being fired from an aircraft traveling at such speed. ar-jedi |
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Posted: 12/28/2015 11:58:34 PM EST
[#43]
Nope. It is a gunnery thread. Which is the practical application of physics and as such is well documented.
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Posted: 12/28/2015 11:59:38 PM EST
[#44]
Quote HistoryQuoted:
oh great, another GD physics thread. here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k ar-jedi Quote HistoryQuoted:
oh great, another GD physics thread. here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k The projectile sitting in the chamber of the gun is motionless in relation to the chamber, barrel, etc. If the muzzle velocity of the projectile is 2,800 fps, the muzzle velocity is 2,800 fps regardless of the aircraft velocity. Show me an equation that demonstrates a .50 cal projectile, or any other, gains an additional 2,000 fps by being fired from an aircraft traveling at such speed. ar-jedi So, dazzle us with the artillery gunnery pedigrees of yourself and leatherface_y2k. If you haven't noticed, the bulk of the people who are stating that the Earth's rotation does, in fact, play a part in flight of an artillery round are current or former Artillerymen-those who do or have done this stuff for a living where the lives of others depended on their skill and expertise. 
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Posted: 12/29/2015 12:16:20 AM EST
[#45]
Quote HistoryQuoted:
oh great, another GD physics thread. here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k ar-jedi Quote HistoryQuoted:
oh great, another GD physics thread. here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k The projectile sitting in the chamber of the gun is motionless in relation to the chamber, barrel, etc. If the muzzle velocity of the projectile is 2,800 fps, the muzzle velocity is 2,800 fps regardless of the aircraft velocity. Show me an equation that demonstrates a .50 cal projectile, or any other, gains an additional 2,000 fps by being fired from an aircraft traveling at such speed. ar-jedi 
GD physics is best physics. |
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Posted: 12/29/2015 12:19:32 AM EST
[#46]
The shell flies no further but the earth does turn underneath it. Just a wag.
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Posted: 12/29/2015 1:31:29 AM EST
[#47]
Quote HistoryQuoted:
So, dazzle us with the artillery gunnery pedigrees of yourself and leatherface_y2k. If you haven't noticed, the bulk of the people who are stating that the Earth's rotation does, in fact, play a part in flight of an artillery round are current or former Artillerymen-those who do or have done this stuff for a living where the lives of others depended on their skill and expertise. no, really? ar-jedi |
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Posted: 12/29/2015 1:37:06 AM EST
[#48]
Quote HistoryQuoted:
GD physics is best physics. Quote HistoryQuoted:
Quoted:
oh great, another GD physics thread. here's the last one: http://www.ar15.com/forums/t_1_5/1749787__ARCHIVED_THREAD____A_fighter_is_flying_supersonic_and_fires_its_forward_facing_cannon__how_fast_does_the_projectile_go_.html&page=1 leatherface_y2k The projectile sitting in the chamber of the gun is motionless in relation to the chamber, barrel, etc. If the muzzle velocity of the projectile is 2,800 fps, the muzzle velocity is 2,800 fps regardless of the aircraft velocity. Show me an equation that demonstrates a .50 cal projectile, or any other, gains an additional 2,000 fps by being fired from an aircraft traveling at such speed. ar-jedi
GD physics is best physics. i have a whole collection of best GD physics... http://www.ar15.com/forums/t_1_5/934132__ARCHIVED_THREAD____Which_material_is_stiffest__Wood__graphite__aluminum__carbon_fiber.html&page=1#i19618624 ar-jedi |
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Posted: 12/29/2015 1:46:17 AM EST
[#49]
A certain speed parallel with the Earth's surface will cause it to orbit. Less than that speed will cause it to travel far, but crash eventually. Space rockets are launched towards the east because they get the boost from the Earth's rotation. If you launch two identical suborbital rockets with identical trajectories east and west from the same point, the one launched towards the east will travel further than the one launched west before crashing.
It should be the same for bullets. The effect of the atmosphere merely slows things down, it doesn't negate this effect. I would expect that a bullet fired towards the east would travel slightly further than a bullet fired towards the west, assuming that all other variables are identical. |
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Posted: 12/29/2015 1:46:49 AM EST
[#50]
Quote HistoryQuoted:
There's two kinds of Artillerymen: Cannoneers and Rocket Queers. :) <a href="http://s123.photobucket.com/user/psi2006/media/M110_zps21aeef5a.jpg.html" target="_blank">http://i123.photobucket.com/albums/o306/psi2006/M110_zps21aeef5a.jpg</a> Quote HistoryQuoted:
Quoted:
Are we talking real mans artillery? The kind you tow? Or are we talking that gay rocket artillery? Or the Trannie SP (like having your own treadmill) heavy artillery? There's two kinds of Artillerymen: Cannoneers and Rocket Queers. :) <a href="http://s123.photobucket.com/user/psi2006/media/M110_zps21aeef5a.jpg.html" target="_blank">http://i123.photobucket.com/albums/o306/psi2006/M110_zps21aeef5a.jpg</a> So we're discussing Tranny Artillery in GD. Well I can't say I'm surprised. |
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