Education!

[S2]

1979 Reply

"Deflection and Quadrant is the artillery terminology for Direction and Elevation."

"How does Elevation get computed ?"

Arty Engineer had it nearly correct. However the term to raise or lower the tube is, specifically, Quadrant elevation (QE). It is announced by the FDC to the guns as QUADRANT, such as "Quadrant 472".

Quadrant elevation is the algebraic sum of angle of site, site and elevation. Here is the FM 6-40 (Field Artillery Gunnery) definition for each-

1. Angle Of Site- the vertical angle between the level base of the trajectory anchor horizontal and the line of site.

2. Site- the sum of angle of site plus complementary angle of site. Complementary angle of site is computed by multiplying the complementary site factor with angle of site for a given range (extrapolate to the nearest 100m).

3. Elevation- the vertical angle between horizontal and the axis of the bore or rail of the weapon required for a projectile to reach a prescribed range.

Angle of site plus complementary angle of site equal site. Site plus elevation equal QUADRANT ELEVATION. This is the data placed onto the gun to raise or lower the tube.

This data is commonly generated by computer now. Manual gunnery techniques allow for computation of quadrant elevation for a given weapon system and propellant charge either by GFT (Graphical Firing Table) and GST (Graphical Site Table) on two separate sliding sticks or TFT (Tabular Firing Table-a book).

Finally, receipt within the fire command from the FDC of QE by the weapon's chief of section connotes authorization to fire unless otherwise restricted by special instructions (At My Command or Do Not Load).

[1979]

Manual gunnery techniques allow for computation of quadrant elevation for a given weapon system and propellant charge either by GFT (Graphical Firing Table) and GST (Graphical Site Table) on two separate sliding sticks or TFT (Tabular Firing Table-a book).

ok thanks . I assume that in difficult terrain you have to also factor in , the obstacles ( mountains ) in the way.

[S2]

1979 Reply

The battery executive officer in U.S. Army artillery units computes something known as X.O.'s Minimum Q.E. This is the lowest possible quadrant elevation required by all guns to clear the highest crest or obstacle to the battery's immediate front along it's primary direction of fire and is reported to the FDC. Should that direction of fire change, so too the X.O's Minimum Q.E. This computation is performed for each charge and ammunition type expected to be fired from that positon.

The battery Fire Direction Officer is required to compute the quadrant elevation necessary to clear all intervening crests between that point and the target.

[1979]

This computation is computed for each charge and ammunition type expected to fired from that positon.
The battery Fire Direction Officer is required to compute the quadrant elevation necessary to clear all intervening crests between that point and the target.

if i understand corectly that elevation it's computed but it's never actualy used ...

[bigross86]

It's simple logic: You wanna shoot over the mountain, not at the mountain.

[1979]

It's simple logic: You wanna shoot over the mountain, not at the mountain.

probably i want to shoot at the reverse slope of the mountain.

[bigross86]

Depending on how high/close the mountain is, I'm guessing you're shooting at some pretty steep angles...

[dave lukins]

physics
Gravity always beats lift and drag beats thrust.
However I'm not sure how much lift or drag a shell generates in flight.

What about spin

[S2]

Lukins Reply

"What about spin"

Barrels are rifled to produce a clockwise twist. As such we always correct drift (as it's called) to the left. Modest amount at typical engagement ranges but is skewed heavily when engaging with high angle fire because of the very long time-of-flight.

[bigross86]

I left that out, I wasn't aware that artillery cannons have them. I get my experience from tanks, I know that the Merkava 2 has a rifles barrel, but the Merkava 4 is smoothbore.

[gunnut]

The battery executive officer in U.S. Army artillery units computes something known as X.O.'s Minimum Q.E. This is the lowest possible quadrant elevation required by all guns to clear the highest crest or obstacle to the battery's immediate front along it's primary direction offire and is reported to the FDC. Should that direction of fire change, so too the X.O's Minimum Q.E. This computation is computed for each charge and ammunition type expected to fired from that positon.

The battery Fire Direction Officer is required to compute the quadrant elevation necessary to clear all intervening crests between that point and the target.

Sir, how are all these numbers calculated? Is it some guy sitting at a table with a pocket calculator and a book of charts? Or is it more high tech like entering a bunch of numbers and take the readings on the screen? If needed, can people still manually calculate these numbers by pencil and paper?

[Pakmiran]

Fire-For-Effect is a request made by the forward observer to deliver the full measure of fire for a particular mission onto the intended target. It may be requested immediately or upon completion of the adjustment phase (if necessary) but denotes that the target is solidly located relative to the observed fall of shot.

The intent is always to achieve fire-for-effect at the earliest possible opportunity. This hopefully preserves surprise at the target while reducing both gun exposure and ammunition expenditure. With an accurately located observation post, a surveyed firing position, good velocity error and metro data available, and a nearly-precise range and direction from the observer even targets of opportunity can be engaged with fire-for-effect immediately.

So if I understand this correctly, fire-for-effect is using the full potential firepower of the battery in as short of a window as possible?

[S2]

Pakmiran Reply

"...fire-for-effect is using the full potential firepower of the battery in as short of a window as possible?"

The goal has always and remains to achieve effective first round fire-for-effect. If all conditions have been properly accounted then there's no reason that the first iteration of fires won't be fire-for-effect.

Doing so is the expectation of professional cannoneers.

[S2]

gunnut Reply

"Sir, how are all these numbers calculated?"

Carefully. Not trying to be a smartazz but there's a lot involved at every level of the field artillery system to make it happen.

"Is it some guy sitting at a table with a pocket calculator and a book of charts? Or is it more high tech like entering a bunch of numbers and take the readings on the screen?"

It could be either.

"If needed, can people still manually calculate these numbers by pencil and paper?"

Supposedly. I sometimes now wonder.

[bigross86]

Again, bit off topic, but when I was in training, my TC's favorite pastime was shutting off my FCS and watching me do everything manually. They don't do that in artillery?