SUBSIM Radio Room Forums - View Single Post - Zero Gyro Angle-No TDC Required Firing method video

gumbeauregard · 08-29-17, 11:53 PM

Part 2 addresses how this method is used at AOB other than 90 degrees but here is the summary

There are two triangles available to solve allowing precise calculation of the firing angle for any AOB. Before the digital age, solving two triangles was not as easy as it is now so it was not operationally feasible to calculate this on the fly.

However, rules of thumb were developed.

In Part 2 one can see that the 90 degree AOB firing angle is valid for ANY AOB from 90 to 120 degrees. At AOB of 135 the firing angle is about 85% of the 90 degree angle.

At 60 degrees AOB it is 75%
At 40 it is 50%
At 18 it is 25%

So in any case, once you know your 90 degree AOB firing angle you can quickly mentally compute the required firing angle for any AOB.

Or you can build a calculator to solve the two triangles like I did but the rules of thumb are accurate enough inside 1500 yards.

I want to emphasize that I make no claims as to authoring ANY of this. Everything I use comes from the guys who actually did this in WWII and the ancient Greeks who invented trigonometry and figured all this out.

08-29-17, 11:53 PM	#3
gumbeauregard Seaman Join Date: Feb 2008 Location: Houston, Texas Posts: 41 Downloads: 16 Uploads: 0	Part 2 addresses how this method is used at AOB other than 90 degrees but here is the summary There are two triangles available to solve allowing precise calculation of the firing angle for any AOB. Before the digital age, solving two triangles was not as easy as it is now so it was not operationally feasible to calculate this on the fly. However, rules of thumb were developed. In Part 2 one can see that the 90 degree AOB firing angle is valid for ANY AOB from 90 to 120 degrees. At AOB of 135 the firing angle is about 85% of the 90 degree angle. At 60 degrees AOB it is 75% At 40 it is 50% At 18 it is 25% So in any case, once you know your 90 degree AOB firing angle you can quickly mentally compute the required firing angle for any AOB. Or you can build a calculator to solve the two triangles like I did but the rules of thumb are accurate enough inside 1500 yards. I want to emphasize that I make no claims as to authoring ANY of this. Everything I use comes from the guys who actually did this in WWII and the ancient Greeks who invented trigonometry and figured all this out. Last edited by gumbeauregard; 08-30-17 at 01:38 AM.