Zero gyro shooting

TorpX · 03-07-13, 01:06 AM

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.]

03-07-13, 01:06 AM	#11
TorpX Silent Hunter Join Date: Sep 2010 Posts: 3,975 Downloads: 153 Uploads: 11	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.]