How did they adjust the elavation on union mortars

[rusty barrels]

I can see how they did it on confederate sleds but I don't see it on union mortars. Did they use a wedge under the base?

[Rickk]

I messed with some computer simulations a while ago and realized that when firing at 45 degrees, distance changes due to muzzle velocity errors are smaller than at any other angle. That translates to best accuracy capability when firing at 45 degrees. They probably did all their tables at 45 degrees because of this.

Impact area would have been adjusted only by powder charge changes or moving the entire mortar.

All that aside, a wedge under either the front or back to change from 45 degrees will always move the point of impact closer to you. If you shoot higher angles, it will hit closer but bury itself deeper. If you shoot lower angles it will hit closer but possibly roll if it doesn't stop when it hits.

[Double D]

The barrels were fixed in the coehorn and range was determined by adjustment in powder charge

[Artilleryman]

As DD stated all standard coehorns had a fixed elevation of 45 degrees provided the bed was sitting on a level platform.  On seige mortars you can change the elevation, but all of the range tables use 45 degrees for the various charges. 

[GGaskill]

Plus they tried to cut the fuzes so the shells exploded above the target and thus rained the fragments on the enemy with the velocity of the falling shell.

[rusty barrels]

That's interesting about the degrees and impact distance, but after thinking about it, that would be true. So did they pour the powder down the tube loose or did they have various charges aready packed.

[Cat Whisperer]

Plus they tried to cut the fuzes so the shells exploded above the target and thus rained the fragments on the enemy with the velocity of the falling shell.

True, and at close quarters, they'd shoot at high angle with long-timed fusing to penetrate the bunkers.  (Note some of the battlefields with massive earthworks sometimes only 100yards separating the opposing forces.)

[Artilleryman]

That's interesting about the degrees and impact distance, but after thinking about it, that would be true. So did they pour the powder down the tube loose or did they have various charges aready packed.

Rusty, They poured powder from a cartridge bag into all mortars except the seacoast mortars.  The inserted the cartridge bag and rammed it in the seacoast mortars.

[Cannonmaker]

The Military a hundard forty years ago was somewhat conservative, beleve it or not. During the course of the Civil War the Federal's purchased  7,428,142 lbs of Mortar powder, that is between Jan. 1 1861 to June 30, 1866.

 Angle of 45 deg. gives max. range, therefore the distance being determond by power charge would give the best performance for the least amount of powder used. The Coehorn  bed would be placed on a platform which was leveled.

Rick

[Artilleryman]

Of that 7,428,142 lbs most of it was probably used by field pieces.  I know that the 10, 20, and 30 pdr. Parrotts used mortar powder.  I hate making assumptions but I would assume that there were other field pieces that also used mortar powder.  Mortar powder appears to be equal to 1Fg powder.  When I use 1Fg in my 8 inch mortar I get pretty close to the same range as noted in the range tables.  When I use cannon grade the shells fall over 100 yards short using the same weight of powder.  The range at which I noted this was 900 yards.

[CU_Cannon]

Angle of 45 deg. gives max. range

This is true in a world without air.  The actual angle for optimal range is around 33 deg.  This was well known even before the Civil War.  I would say that the 45 deg angle gave a combination of range and impact angle.

[Cat Whisperer]

Angle of 45 deg. gives max. range

This is true in a world without air.  The actual angle for optimal range is around 33 deg.  This was well known even before the Civil War.  I would say that the 45 deg angle gave a combination of range and impact angle.

I would like to see some imperical evidence of what the max range is for a given charge and specified weight and SHAPE bullet fired from a mortar at various angles.

It's easy to see from the firing tables of modern artillary the exact elevation that divides low and high angles.  Terms used to define above or below that dividing point.  With both (anything above that for high angle and anything below that for low angle) the round is going to hit closer and closer as the deviation from that angle increases.

The shape makes a difference - a long pointed bullet will travel essentially straight and turn down some as it goes over it's highest point, causing a distinct effect on it.

Spheres have a different trajectory, hence the dividing point between high and low angles is different - how much different I've not seen from published tables of fire.

I think there's room for more discussion.

[Rickk]

At high velocities there is deviation from the optimum angle being 45 degrees. At lower velocities it is very close to 45 degrees.

It all boils down to "does a wooden ball ball as fast as a lead ball when dropped from the leaning tower of pizza?". Rumor has it that they do.

Eventually, if the velocity became high enough, air resistance would slow down the lighter ball. If the velocity is high enough that air resistance slows down a heavy lead (or whatever) ball, then a lower angle will get you further.

When shooting a mortar 100 yards at 45 degrees, the muzzle velocity is something like 200 feet per second. At peak altitude (50 feet), the velocity is only about 141 feet/sec. At impact, it would be back up to just about 200 feet/sec.... overall a pretty slow round.

I guess in the civil war they were shootin alot further than 100 yards, so the muzzle velocity would have been alot faster, and air resistance would have become fairly significant.