Quote:
Originally Posted by TorpX
Dignan,
I'm not sure whether you are using a scientific calculator or something else. Any dedicated calculator should have a degree mode. If not it would be computing in radians. Check this by trying this:
sin 90 = 1 and arcsin 1 = 90 [degree mode]
sin (3.1415927/2) = 1 and arcsin 1 = 1.570796... [radian mode]
[pi radians = 180 degrees]
Be careful about the track angle, intercept angle and the AoB. They are all different angles. IMO, the track angle is less confusing to use. This is a good way to calculate the Lead Angle:
La = arctan((Vt sin Ta)/(Vp + Vt cos Ta))
where
Vt is target speed,
Vp is torpedo speed
Ta is track angle
or, if you must use radians and convert:Ta1 = Ta * (pi/180):
La1 = arctan((Vt sin Ta1)/(Vp + Vt cos Ta1)):
La = La1 * (180/pi)
There are diagrams which show the geometry of the set-up at the start of the Algebraic Firing Solution thread.
[I didn't get the right answer when I tried Pisces formula. Either he left something out or I'm fouling it up tonight.]
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Ah, I think I see my mis-step. I was failing to convert the final La result into radians too. I converted the input (Ta in your formula above) to radians but not my final La output. Regarding my calculator, its something I downloaded for free on my phone. It's possible the person who made it did not do it correctly or did not include a way to automatically convert to radians. Some of them are better than others.
Thanks a lot. I'll try this tonight. If it doesn't work I"ll probably just go back to drawing it out on the nav map. Not that big of a deal. I try to remind myself that somewhere under all this putzing around with mods and formulas and stuff there's a game to be played.