SUBSIM Radio Room Forums - View Single Post - Basic question re the TDC in ATO/KIUB mod

Fincuan · 03-13-11, 06:30 AM

I'll play a bit of Mythbusters first:

The German TDC doesn't have a PK
CONFIRMED, there is indeed no PK.
The American TDC tracks even though the PK is off
BUSTED, it does not track if the PK is switched off. That's the whole purpose of switching it off.

What the German TDC does is give you the correct lead-angle based on your speed, AOB and inputs. It does not actively track anything.

Doing all the 75 degree things just makes it all seem overly complicated, while it really isnt't. The technique mostly used with the German TDC is commonly called "Fast-90", and has been around at least as long as SH3, probably even longer. One way to do it:

Get to a position 500 - 1000 meters off the target's track, at a 90 degree angle to the track.
Point your scope to 0-bearing if your bow is pointing at the track, or 180 if it's your stern pointing at the track.
Disengage the scope from the TDC, ie. "turn off" the TDC. This is the famous button with a light.
Input target speed and approximate distance to the track at the moment of firing. Distance doesn't need to be all that precise if you fire as close to 0-gyro angle as possible.
Turn AOB dial to 90 degrees port if target is approaching you from the right, and vice-versa if it's coming from the left. This is what the target's AOB will be when it crosses your nose or stern.
Re-enage the TDC, "the blue button".
Now your scope acts as a point and shoot device, ie. it automatically updates the correct AOB when you wheel it around, provided that neither you or the target changes course. If you need to change either speed or range inputs just disengage the TDC, change the input and then re-engage TDC. Just make sure you don't turn the scope or the AOB dial while the TDC is disengaged. Then again if you fire while the target is within 20-degrees of your nose the gyro-angle is usually small enough so that range doesn't really matter. You can also use the gyro-angle dial in the TDC to find the precise bearing where gyro-angle will be zero.

Source: Wazoo's FAST-90 tutorial

03-13-11, 06:30 AM	#2
Fincuan Admiral Join Date: Aug 2007 Location: Suomi, sauna, puukko, perkele Posts: 2,346 Downloads: 39 Uploads: 0	I'll play a bit of Mythbusters first: The German TDC doesn't have a PK CONFIRMED, there is indeed no PK. The American TDC tracks even though the PK is off BUSTED, it does not track if the PK is switched off. That's the whole purpose of switching it off. What the German TDC does is give you the correct lead-angle based on your speed, AOB and inputs. It does not actively track anything. Doing all the 75 degree things just makes it all seem overly complicated, while it really isnt't. The technique mostly used with the German TDC is commonly called "Fast-90", and has been around at least as long as SH3, probably even longer. One way to do it: Get to a position 500 - 1000 meters off the target's track, at a 90 degree angle to the track. Point your scope to 0-bearing if your bow is pointing at the track, or 180 if it's your stern pointing at the track. Disengage the scope from the TDC, ie. "turn off" the TDC. This is the famous button with a light. Input target speed and approximate distance to the track at the moment of firing. Distance doesn't need to be all that precise if you fire as close to 0-gyro angle as possible. Turn AOB dial to 90 degrees port if target is approaching you from the right, and vice-versa if it's coming from the left. This is what the target's AOB will be when it crosses your nose or stern. Re-enage the TDC, "the blue button". Now your scope acts as a point and shoot device, ie. it automatically updates the correct AOB when you wheel it around, provided that neither you or the target changes course. If you need to change either speed or range inputs just disengage the TDC, change the input and then re-engage TDC. Just make sure you don't turn the scope or the AOB dial while the TDC is disengaged. Then again if you fire while the target is within 20-degrees of your nose the gyro-angle is usually small enough so that range doesn't really matter. You can also use the gyro-angle dial in the TDC to find the precise bearing where gyro-angle will be zero. Source: Wazoo's FAST-90 tutorial