Sorry I did not participate in this thread earlier. As a FDC Chief at the battery and Squadron (Cavalry) levels I was getting a charge out of some of the calls for fire. I too went to Fort Sill for both basic and AIT as a 13E. Though I crewed a M577 Command Post Carrier, I was near the guns to calculate all of the firing data and sent the commands to them. My first assignment was to 1/29th Field Artillery within the 4th Infantry Div. at Fort Carson, CO; it was an M109 unit. My next assignment was in West Germany from 79-83, then assigned to 2/83rd FA (M110A2, 8 inch nuclear capable howitzers). This was during the Cold War. Later after getting another MOS, but being a career soldier, I was reassigned according to the needs of the Army, back to a 13E FDC slot in the 3rd Squadron 3rd Armored Cavalry Regiment. Each squadron has its own artillery battery (M109's). With three cavalry squadrons in the 3rd Regiment we effectlvely had a artillery battalion. Here I was the FDC Chief in Charlie Battery, as an E-6 and later transferred to Squadron S-3 (Operations) to double duty as the Squadron Chemical NCO (54E) and Fire Support NCO (13E) both as E-7.
Over the years I received calls for fire missions from American Army, Marines, German and Italian Army soldiers. I remember receiving adjust fire missions, supressive fires, DEFCON FPF's, zone and sweep, high angle, illumination, and nuclear missions. When I started in the military there were no computers to calculate the firing data. You had a military map (with terrian elevation), your plotting chart, and Range Deflection Protractor (RDP) Graphic Site Table (GST), Graphic Firing Table (GFT), etc. You received metriological updates for tempreture, air density, wind direction / speed, etc. After calculating the barometric corrections they would be plotted on the GFT (time, elevation and drift). There also were no digital/encrypted communications so each fire mission had to be authenticated through a CEOI. Later FADAC, TI-59, and TACFIRE computers as well as digital and encrypted communications updated the process and basically eliminated the need to authenticate through a CEOI. I really doubt if an FDC specialist even gets trained in the manual/manual method anymore. The data sent to the guns were a deflection (right or left of the battery laid position); quadrant (barrel up or down basically elevation for distance); and Time for a fuze setting (for anything other than HE/PD rounds).
A battery had 6 guns and normally the most proficient gun was set in the three or four position as "base piece". They were the single round adjusting gun on adjust fire missions...to site in or adjust the round to the target. Once the steel was on target the FIST or Foward Observer would call in the "Fire For Effect" command. Based on the target description the FDC would then call for the entire battery to load up. Depending on the mission it could be one command to fire, fire when ready, or fire by command (a single or multiple rounds).
One of the wildest fire missions to see as an FDO is a "zone and sweep" mission. This is basically quilting a target. Lets say for example, the size of a grid square (1K), where a round falls at a designated spread, normally every 50 or 100 meters. A mission of this size was not done with one battery but with a batallion or brigade level mission.
One of the craziest missions to watch from the battery position is a final protective fire FPF while using a "bee hive" round. Talk to anyone who has seen it, they will tell you. It is great for clearing a tree line too. Strange sound going down range, but devestating. I could talk all day about this.....
But I cannot wait to see this build progress. Are you going to also build the FDC M577 or the ammo carrier (M548, Gore, or?)???
Keep up the great work!
Ben