Delay for Rapid Fire TNT Cannon?

Question

I build a rapid fire TNT cannon. The first lever is to activate the payload clock and the second lever activates the projectile clock. I want to automate it so that I only use one lever to start the ENTIRE process. Here's the save: https://www.dropbox.com/s/1616g0dl55ygf2e/TNT%20Cannon.zip Any suggestions?

Answer 1

I would recommend a delay of 39 redstone ticks (3.9 seconds), meaning nine four-tick repeaters and one three-tick repeater. The reasoning is that TNT explodes in 4 seconds:

If the block was activated by redstone or fire, the delay will be 4 seconds;

Those 39 redstone ticks activate the projectile just in time, giving the longest possible time between being launched and exploding.