Bishthebosh

Military take Earth rotation into account when firing shells
« on: January 31, 2019, 04:53:30 PM »
I’ve seen stuff on the calculations needed to fire ordnance over long distances. They have very complex tables of figures that take into account air density (barometric pressure) and the curvature of the Earth. These tables were calculated due to the amount of misses in the early days of field and ship heavy guns. Why would the military have such tables made for artillery to use if they did not accurately predict where ordnance were going to land? Here is a link to a video about this

As is pointed out in the video - Why the heck would the military put their own troops lives on the line with inaccurate data and risk losing a battle/war? Makes no sense.

My challenge is for FE community folks to look at the video and explain how this sits with FE theory.

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Offline WellRoundedIndividual

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Re: Military take Earth rotation into account when firing shells
« Reply #1 on: January 31, 2019, 05:08:38 PM »
This has been addressed in another topic thread. The FE rebuttal is that the calculations are wrong due to their claim that targets are missed frequently by artillery, and that that therefore proves that the curvature of the earth is nonexistent. There was also a discussion about the Coriolis effect, which the FE group claims does not exist by the same reasoning.
BobLawBlah.

Bishthebosh

Re: Military take Earth rotation into account when firing shells
« Reply #2 on: January 31, 2019, 05:21:08 PM »
This has been addressed in another topic thread. The FE rebuttal is that the calculations are wrong due to their claim that targets are missed frequently by artillery, and that that therefore proves that the curvature of the earth is nonexistent. There was also a discussion about the Coriolis effect, which the FE group claims does not exist by the same reasoning.

That doesn’t surprise me at all. As I understand it, the fact that there are still lots of misses is due lots of things, not least the fact that targets are more often than not moving, wind effects which are very difficult to predict and will have more of an an effect over long distances etc. Prior to the calculations the misses were far higher! In pro shooting however, targets are stationary, and accuracy from pro shooters is way high uses these tables.

OhBoy

Re: Military take Earth rotation into account when firing shells
« Reply #3 on: February 15, 2019, 04:12:54 AM »
@WellRoundedIndividual

Can you link this thread?

You have evidence of the Coriolis force with some not to difficult derivations. How does one come to the conclusion that it doesn't exist?

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Offline stack

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Re: Military take Earth rotation into account when firing shells
« Reply #4 on: February 15, 2019, 04:36:51 AM »
This from a recent thread on the subject. Never got a direct response.

When we looked into it further we found that there was no evidence for the effect at all. It's an unfounded claim.

https://wiki.tfes.org/The_Coriolis_Effect

https://wiki.tfes.org/Coriolis_Effect_(Weather)

From the wiki (https://wiki.tfes.org/The_Coriolis_Effect) referencing the “Coriolis” Correction Table H from the "The Production of Firing Tables for Cannon Artillery (1967)” doc, it states:

"When Coriolis Effect proponents are challenged on the accuracy or validity of this table, the proponents proclaim that if it were incorrect then artillery and artillerymen would be routinely inaccurate and miss their targets, and how could that be the case?
From the introduction of the above paper provided to us we read that military artillery, which is purported to require adjustments for the "Coriolis Effect," is indeed, routinely inaccurate. The first round generally misses its target. Only after missing a number of times, and then adjusting the alignment of the cannon to compensate, does the artilleryman hit his or her target.”


And it goes on to list a series of quotes regarding the accuracy of firing tables and how most first rounds fired are inaccurate.

So is the argument that because the Coriolis Table H is used but most first rounds are not accurate that the Coriolis Effect doesn’t exist?

If so, wouldn’t the same apply to Tables A-G and I-M. Things like table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc? Meaning, do all of these things not exist as well because often the first round(s) fired are not accurate?
Not much is known about the celestial bodies and their distances.

Re: Military take Earth rotation into account when firing shells
« Reply #5 on: February 15, 2019, 04:14:12 PM »
The military does not take curvature into account.

Rail guns disprove the spherical earth.

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Re: Military take Earth rotation into account when firing shells
« Reply #6 on: February 15, 2019, 09:47:27 PM »
The military does not take curvature into account.

Incorrect. For artillery fire, depending upon range to target, they do.

Rail guns disprove the spherical earth.

Incorrect.

Not much is known about the celestial bodies and their distances.

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Offline Tom Bishop

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Re: Military take Earth rotation into account when firing shells
« Reply #7 on: February 15, 2019, 11:17:21 PM »
What is the illustration supposed to show? Looks like a straight baseline in that illustration to me.

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Re: Military take Earth rotation into account when firing shells
« Reply #8 on: February 15, 2019, 11:52:58 PM »
What is the illustration supposed to show? Looks like a straight baseline in that illustration to me.

Indirect fire means non line of sight (NLOS). Rail gun projectiles are fired in the same manner as regular ballistic shells.

Not much is known about the celestial bodies and their distances.

Re: Military take Earth rotation into account when firing shells
« Reply #9 on: February 16, 2019, 12:12:50 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles?  Even if you believe in the Coriolis effect, Sandokhan has already shown that the Coriolis effect doesn't prove the Earth spins rather it could be the ether that spins (see his posts on Mach's principle.) 
« Last Edit: February 16, 2019, 12:32:38 AM by George Jetson »

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Re: Military take Earth rotation into account when firing shells
« Reply #10 on: February 16, 2019, 12:56:44 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles? 

They do. Magnitudes are different. Planes are flown/guided, projectiles are not.

Even if you believe in the Coriolis effect, Sandokhan has already shown that the Coriolis effect doesn't prove the Earth spins rather it could be the ether that spins (see his posts on Mach's principle.)

Could be. However lots of evidence says otherwise.

Point being, the wiki is using an incorrect argument. The ballistics firing tables are used to calculate the path of a projectile to its target. The wiki argument is that they are often not very accurate so the Coriolis table must be moot. However, that argument would mean all the table corrections are moot, not just the Coriolis one. So why have table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc., as well if they are not needed?
Not much is known about the celestial bodies and their distances.

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Offline TomFoolery

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Re: Military take Earth rotation into account when firing shells
« Reply #11 on: February 16, 2019, 01:13:53 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles?  Even if you believe in the Coriolis effect, Sandokhan has already shown that the Coriolis effect doesn't prove the Earth spins rather it could be the ether that spins (see his posts on Mach's principle.)

If I may offer just a point of clarifiaction ;D
Except in business, poetic or literary settings, I think "trajectory" is generally more used on things that reach their destination without the need of the air.
In other words, rockets, bullets, etc. They are launched at a high speed and either momentum carries them or a solid fuel rocket propels them, but they could just as easily (if not more easily) "fly their course" and reach their destination without air. Think of the word ballistic.

Airplanes and helicopters on the other hand are supported by air constantly. I mean, if the air were to suddenly vanish mid flight, you could say an airplane had a trajectory since it has mass and velocity so it would move forward briefly before dropping down, but it wouldn't reach its destination and that's not how they fly.

Airplanes and helicopters do not have a trajectory in the normal sense, because they are constantly accelerating air downward to produce lift. If they are producing more lift than their weight, they climb. If less lift, they sink. If equal lift, they maintain altitude.

The pilot or the autopilot constantly watches the altimeter and constantly adjusts throttle and other controls to maintain the desired altitude. Without that, the plain would go higher and higher or lower and lower till it crashed.

It really doesn't have anything to do with the earth rotating or not or curved or flat - it's just how you fly a plane. I used to build and fly model planes so this is a first hand experience for me.

This really is all a side note from the question, but hopefully brings some clarity.

Re: Military take Earth rotation into account when firing shells
« Reply #12 on: February 16, 2019, 02:57:10 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles? 

They do. Magnitudes are different. Planes are flown/guided, projectiles are not.
Whenever the question is asked by Flat Earthers the Round Earthers say that there is no correction needed because the atmosphere compensates for the Coriolis force or because of "conservation of momentum" which somehow magically causes curved motion even though inertia normally results in straight line motion per Newton's first law. 

This Stackexchange page attests to this consensus belief:  https://physics.stackexchange.com/questions/16390/does-the-rotation-of-the-earth-dramatically-affect-airplane-flight-time

During the flight, you need to get up to use the restroom. There's one 10 rows in front of you, and another 10 rows behind you. Does it take longer to walk to the one that's moving away from you at 600 mph than the one that's moving towards you at 600 mph?

"No, because you're moving at 600 mph right along with it -- in the ground-based frame of reference. In the frame of reference of the airplane, everything is stationary.

Similarly, the airplane is already moving along with the surface of the Earth before it takes off. The rotation of the Earth has no direct significant effect on flight times in either direction.

That's to a first order approximation. As others have already said, since the Earth's surface is (very nearly) spherical and is rotating rather than moving linearly, Coriolis effects can be significant. But prevailing winds (which themselves are caused by Coriolis and other effects) are more significant that any direct Coriolis effect on the airplane."


None of the experts ever mention any Coriolis corrections in airplanes.


« Last Edit: February 16, 2019, 03:02:28 AM by George Jetson »

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Re: Military take Earth rotation into account when firing shells
« Reply #13 on: February 16, 2019, 03:29:02 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles? 

They do. Magnitudes are different. Planes are flown/guided, projectiles are not.
Whenever the question is asked by Flat Earthers the Round Earthers say that there is no correction needed because the atmosphere compensates for the Coriolis force or because of "conservation of momentum" which somehow magically causes curved motion even though inertia normally results in straight line motion per Newton's first law. 

This Stackexchange page attests to this consensus belief:  https://physics.stackexchange.com/questions/16390/does-the-rotation-of-the-earth-dramatically-affect-airplane-flight-time

During the flight, you need to get up to use the restroom. There's one 10 rows in front of you, and another 10 rows behind you. Does it take longer to walk to the one that's moving away from you at 600 mph than the one that's moving towards you at 600 mph?

"No, because you're moving at 600 mph right along with it -- in the ground-based frame of reference. In the frame of reference of the airplane, everything is stationary.

Similarly, the airplane is already moving along with the surface of the Earth before it takes off. The rotation of the Earth has no direct significant effect on flight times in either direction.

That's to a first order approximation. As others have already said, since the Earth's surface is (very nearly) spherical and is rotating rather than moving linearly, Coriolis effects can be significant. But prevailing winds (which themselves are caused by Coriolis and other effects) are more significant that any direct Coriolis effect on the airplane."


None of the experts ever mention any Coriolis corrections in airplanes.

Sure they do. You just didn't read far enough down.

Again, for the umpteenth time, Coriolis is a factor, it's magnitude of such is utterly dependent upon the object it is affecting. Projectile v Plane. In planes, it's factored into Inertial Navigation Systems (INS) that are built into the planes you travel in. There are a lot of factors that dictate what a plane can do and what a projectile can do. Do some googling.

The misunderstanding here is how the TFES wiki throws the baby out with the bathwater:

The wiki argument is that artillery shots are often not very accurate so the Coriolis table must be moot in their manual. However, that argument would mean all the table corrections are moot, not just the Coriolis one. So why have table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc., as well if they are not needed?
Not much is known about the celestial bodies and their distances.

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Offline TomFoolery

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Re: Military take Earth rotation into account when firing shells
« Reply #14 on: February 16, 2019, 03:43:27 AM »
None of the experts ever mention any Coriolis corrections in airplanes.

Sure they do. You just didn't read far enough down.

Again, for the umpteenth time, Coriolis is a factor, it's magnitude of such is utterly dependent upon the object it is affecting. Projectile v Plane. In planes, it's factored into Inertial Navigation Systems (INS) that are built into the planes you travel in. There are a lot of factors that dictate what a plane can do and what a projectile can do. Do some googling.

I love to learn more about all things airplane, could you perchance provide a link explaining that the INS systems for airplanes factor in Coriolis?
(Or if you haven't that, I'd be interested it hearing where you heard it!)

From my research, the gyroscope sensors, whether spinning mechanical or MEMS type, have so much inherent drift already that it  dwarfs coriolis, and all has to be manually (old style) or automatically corrected for by the system, but generally is just corrected for as "drift and error" without any specific model which ties into coriolis.
However I suppose if they were using a good 3 axis laser ring gyro  that had drift far below coriolis then they could model it rather than just correct for drift.

Anyway, I'd be most grateful to know how you came by that information! I'm not saying you're wrong, just trying to expand my knowledge!

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Offline Tom Bishop

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Re: Military take Earth rotation into account when firing shells
« Reply #15 on: February 16, 2019, 03:45:16 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles? 

They do. Magnitudes are different. Planes are flown/guided, projectiles are not.
Whenever the question is asked by Flat Earthers the Round Earthers say that there is no correction needed because the atmosphere compensates for the Coriolis force or because of "conservation of momentum" which somehow magically causes curved motion even though inertia normally results in straight line motion per Newton's first law. 

This Stackexchange page attests to this consensus belief:  https://physics.stackexchange.com/questions/16390/does-the-rotation-of-the-earth-dramatically-affect-airplane-flight-time

During the flight, you need to get up to use the restroom. There's one 10 rows in front of you, and another 10 rows behind you. Does it take longer to walk to the one that's moving away from you at 600 mph than the one that's moving towards you at 600 mph?

"No, because you're moving at 600 mph right along with it -- in the ground-based frame of reference. In the frame of reference of the airplane, everything is stationary.

Similarly, the airplane is already moving along with the surface of the Earth before it takes off. The rotation of the Earth has no direct significant effect on flight times in either direction.

That's to a first order approximation. As others have already said, since the Earth's surface is (very nearly) spherical and is rotating rather than moving linearly, Coriolis effects can be significant. But prevailing winds (which themselves are caused by Coriolis and other effects) are more significant that any direct Coriolis effect on the airplane."


None of the experts ever mention any Coriolis corrections in airplanes.

Sure they do. You just didn't read far enough down.

Again, for the umpteenth time, Coriolis is a factor, it's magnitude of such is utterly dependent upon the object it is affecting. Projectile v Plane. In planes, it's factored into Inertial Navigation Systems (INS) that are built into the planes you travel in. There are a lot of factors that dictate what a plane can do and what a projectile can do. Do some googling.

The misunderstanding here is how the TFES wiki throws the baby out with the bathwater:

The wiki argument is that artillery shots are often not very accurate so the Coriolis table must be moot in their manual. However, that argument would mean all the table corrections are moot, not just the Coriolis one. So why have table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc., as well if they are not needed?

Those are uncertainty budgets. Those variable are not demonstrated to be accurate. If the shot isn't accurate they are compete guesses.

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Re: Military take Earth rotation into account when firing shells
« Reply #16 on: February 16, 2019, 04:16:14 AM »
I'm not sure what you're saying. The point the wiki makes is that, essentially all ballistics artillery firing is just guesswork. Yet they are trained to make calculations based upon table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, and Coriolis, etc. So why are they even bothering to use any of those tables to make calculations? Why are they trained to do so?

One would suspect that the table corrections for all those elements put you in the ballpark. Course correct from there.

But the wiki discounts one table out of many, indiscriminately. The wiki argument is that artillery shots are often not very accurate so the Coriolis table must be unnecessary. However, that argument would mean all the table corrections are unnecessary, not just the Coriolis one. So why have table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc., as well if they are not needed?
Not much is known about the celestial bodies and their distances.

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Offline Tom Bishop

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Re: Military take Earth rotation into account when firing shells
« Reply #17 on: February 16, 2019, 04:19:18 AM »
Those are just put in there to make the contractor look smart to the government. There is no way to verify any single one of those variables if the shot always misses it's target until the forward observer tells the artilleryman how much it missed by to adjust the barrel.

It is possible that they all mean something when combined, and accounts for some average uncertainty. But it is impossible to tell what is what.
« Last Edit: February 16, 2019, 04:22:10 AM by Tom Bishop »

Re: Military take Earth rotation into account when firing shells
« Reply #18 on: February 16, 2019, 04:24:46 AM »
What is the explanation for why the spinning atmosphere, (that is spinning around the axis of the Earth at the same rate as the surface) which supposedly explains why plane and helicopter trajectories do not have to compensate for Earth spin, doesn't have the same effect on projectiles? 

They do. Magnitudes are different. Planes are flown/guided, projectiles are not.
Whenever the question is asked by Flat Earthers the Round Earthers say that there is no correction needed because the atmosphere compensates for the Coriolis force or because of "conservation of momentum" which somehow magically causes curved motion even though inertia normally results in straight line motion per Newton's first law. 

This Stackexchange page attests to this consensus belief:  https://physics.stackexchange.com/questions/16390/does-the-rotation-of-the-earth-dramatically-affect-airplane-flight-time

During the flight, you need to get up to use the restroom. There's one 10 rows in front of you, and another 10 rows behind you. Does it take longer to walk to the one that's moving away from you at 600 mph than the one that's moving towards you at 600 mph?

"No, because you're moving at 600 mph right along with it -- in the ground-based frame of reference. In the frame of reference of the airplane, everything is stationary.

Similarly, the airplane is already moving along with the surface of the Earth before it takes off. The rotation of the Earth has no direct significant effect on flight times in either direction.

That's to a first order approximation. As others have already said, since the Earth's surface is (very nearly) spherical and is rotating rather than moving linearly, Coriolis effects can be significant. But prevailing winds (which themselves are caused by Coriolis and other effects) are more significant that any direct Coriolis effect on the airplane."


None of the experts ever mention any Coriolis corrections in airplanes.

Sure they do. You just didn't read far enough down.

Again, for the umpteenth time, Coriolis is a factor, it's magnitude of such is utterly dependent upon the object it is affecting. Projectile v Plane. In planes, it's factored into Inertial Navigation Systems (INS) that are built into the planes you travel in. There are a lot of factors that dictate what a plane can do and what a projectile can do. Do some googling.

The misunderstanding here is how the TFES wiki throws the baby out with the bathwater:

The wiki argument is that artillery shots are often not very accurate so the Coriolis table must be moot in their manual. However, that argument would mean all the table corrections are moot, not just the Coriolis one. So why have table corrections for Elevation, Wind, Temperature/Density, Muzzle Velocity, etc., as well if they are not needed?
There is no demonstration that the INS used in aircrafts corrects for Coriolis force.  If true, what about before the invention of the INS in the 1950s?  As for your condescension about projectiles vs. aircrafts which can correct themselves, that is the entire basis of the disagreement:  where is the evidence that aircrafts actually use any such correction.

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Re: Military take Earth rotation into account when firing shells
« Reply #19 on: February 16, 2019, 04:52:41 AM »
Those are just put in there to make the contractor look smart to the government. There is no way to verify any single one of those variables if the shot always misses it's target until the forward observer tells the artilleryman how much it missed by to adjust the barrel.

It is possible that they all mean something when combined, and accounts for some average uncertainty. But it is impossible to tell what is what.

Making contractors look good is a sentiment based on some sort of factual data? Or just what you think?

And does the shot ‘always’ miss based upon table corrections?

Just because you can’t tell what’s what doesn’t diminish the need and use for the table corrections.

The wiki makes an erroneous argument: if one table is unnecessary then they all are. I hardly think wind and muzzle velocity table corrections should be discounted, for example. Maybe you know better. Please go on then.
Not much is known about the celestial bodies and their distances.