By Tommy H. Thomason

Thursday, July 24, 2008

Still not easy

The WWII problem - hit an aircraft carrier steaming at 33 knots with a torpedo that runs at 33 knots. This example is a drop roughly abeam the 800-ft long carrier at 2,000 feet, well inside the 1,000 yards usually cited as the maximum drop distance for accuracy. I've revised the calculation to roughly account for a drop from 200 feet (3.5 seconds of air time) and 200 knots, which increases the average speed of the torpedo significantly and therefore reduces the lead required. It's now obvious that the lead is sensitive to the drop speed and altitude, the ballistics (lift/drag) of the torpedo in the air, and the deceleration of the torpedo in the water until it is at its run speed of 33 knots. The good news is that the lead determination is less sensitive to the target speed, although it's still important, and the ship has less time to turn into or away from the torpedo track.


Captain Hook said...

Gene Slover's website has a USN training film (by Walter Lantz!) showing the calculations involved. because of the number of variables-range to target, target speed and bearing, speed of bomber, elevation of bomber, I don't see how an exact solution is possible without a dedicated computer of some sort especially with both target and bomber maneuvering and countermameuvering. There is a "worked out example, but there is a lot of fudge in the recipie.

Tailspin said...

Thanks for that reference: