So, all you’ll need is a couple things:

1. Button (Any type.)
2. Redstone Dust
3. TNT (For TEST ONLY, you need 12.)
4. Dispenser
5. Water
6. Iron Bar/Fence

First place three dispensers like this

Then make it two sides like this

Then, make a square without corners facing into the circle. (YOU DON’T NEED THE RED AND WHITE WOOL.)

Fill the inside with water like this:

Now place an iron bar in the middle:

Put redstone and button like this:

Finally, fill dispensers with TNT.

Done! You’ve made a TNT launcher! The final thing you need to do, is stand on the iron bar, and press the button, TNT will appear around you, but don’t move. It will blast you into the sky! If you want to get back down without dying, just land in the water in the middle (DON’T FALL ON THE IRON BAR).