Which variable(s) are adjusted for artillery targeting?

[Negatron]

I'm more interested in a historical perspective prior to computers being able to solve for optimal results, somewhere in the WW2 era.

Was the common thing then to adjust angle or the amount of charge to get some desired distance? Or was it commonly a combination of both?

Thanks.

 

[Bob S]

Read about the USS Iowa and Missouri 16-inch guns at

http://www.fas.org/man/dod-101/sys/ship/weaps/mk-7.htm

They had charts of range for projectile weight, elevation angle, and number of silk power bags.

the maximum range was about 41,622 yards (38.059 km or 20.55 nm) with nominal 660 lb (300 kg) powder charge. See

http://en.wikipedia.org/wiki/16"/50_caliber_Mark_7_gun

The maximum flight time was nearly 1 1/2 minutes. Most targets could be reached with an elevation angle either under or over 45 degrees. (Nearly?) all projectiles were fired at under 45 degrees elevation. This minimized flight time.

Bob S

 

[Negatron]

Was adjusting the amount of propellant also common for smaller ground artillery? My assumption was that the amount of powder is commonly fixed inside a metal casing and angle is used to alter distance.

 

[DavidSullivan]

Was adjusting the amount of propellant also common for smaller ground artillery? My assumption was that the amount of powder is commonly fixed inside a metal casing and angle is used to alter distance.

You're right - most artillery pieces in WWII used shells with a fixed charge, so range was established by varying the angle of the barrel. I think you could vary the charge used on a mortar, however.

 

[rcgldr]

Tank warfare techonology in the USA took a huge leap that was first demonstrated during the first Iraqi war, "Desert Storm". Until then tank warfare relied on the inaccuracy of the cannons used in tanks. However, the USA had developed the technology to a point it was essentially "one shot, one kill", which obvious the Iraqi's weren't prepared for and the early tank battles were a slaughter until Iraqi figured out it could no longer engage in tank warfare.

Back in WWII days, women were generating partial tables of data for motar rounds, and the earliest computers were being used to do the interpolation to fill those tables. The technology at the time wasn't able to take out the German bunkers that resulted in such a high casualty rate during the D-Day beach assault. Apparently the bombs that aircraft could carry weren't strong enough to destroy the bunkers, so they tried to take them out with ship cannons.

 

[Vanadium 50]

Bob's answer misses an important point. If you have a long flight distance, a fast rate of fire and can change your elevation quickly, you can fire two rounds that impact the target at the same time. This is called "time on target" by the people who do this for a living.

 

[vibjwb]

This may help you
http://www.globalsecurity.org/military/library/policy/army/fm/6-40/Ch7.htm
They’re many variables in powder. Some powder is called “green bag” some “white bag”
With different amounts of green or white you can adjust for the range of the shell.
The temperature of the powder is also considered.
The fire direction center used small sticks that looked like slide rules that were used to make quick manual calculations. These were called Graphical Firing Tables.
The elevation of the barrel combined with the right powder is used to get the desired range. There many more variables than powder and elevation. Things like wind speed wind direction, air density even the earth’s rotation are all part of calculating it manually.
Small artillery like 105 mm use a brass shell casing but large artillery like 155 mm and bigger use a projectile and powder put in the breach and closed.

 

[Negatron]

Interesting, it seems like mostly tabular data and interpolation rather than elegant mathematics. I've noticed from equations with Newton drag that elevations would typically be kept quite low and only increase dramatically close to the maximum range of the weapon, where the travel time also increases dramatically. The high-school kinematics idea of 45 degree optimal angles isn't very useful and often quite wrong for achieving maximum distance.

 

[vibjwb]

It is best to keep the projectile as close to the ground as possible because the enemy has radar that can send there projectile back to the same point yours was fired from. This is called counter battery fire.