After reading the posts everywhere about how to build a launcher, I came up with another variation.
Instead of building the pvc frame with rails and launch pedal fulcrum and then putting a shelf board on top of that, I just used the shelf board as the main structure. 12"x48" shelf board.

The only thing I dont have complete to my satisfaction is the release mechanism. The legs are set up as an H so that I can run the string under the bottom horizontal pipe to act as a pulley to pull the pin out of the board and release the ring. It works, but I need to find something different.

To stake the board and keep it from being pulled away, I have a strap and hook that comes off the back (not pictured) with an adjuster to vary the length. Basically, I attached an adjustable tie down to it and stake behind the whole thing. So, the board is staked in the back and the bungee attaches to the pin in the front of the board. The board bears the load of the bungee. The legs only support the weight of the board and jet. There is no pulling on the legs in any direction.

The launch board takes up very little space and it assembles almost instantly.

The "stopper" to make it stop in the open position is one of those pvc "ez patch" connectors. After it was assembled, I thought "Darn, I should have used a 'T' there to control the opening travel and lock it open".
Anyway, it works.

I suppose you could put launch rails on the sides, but I just wanted to keep it simple. This is not adjustable like the pvc launchers, it does not have rails like the pvc launchers, but it was easy to build, easy to set up, and doesnt take up much space.

There are no rear feet on it as of yet. I may put some on if I need to vary the launch angle.

Any ideas on improving the release mechanism without building the fulcrum/board pedal system?

1 12"x48"x5/8" shelf board
PVC is 3/4"
2 10" pieces (put a T in one if you want to use it as a stopper)
2 2" pieces
2 3" pieces
2 elbows
2 'T's (or 3 if using it as the stopper)
2 slip caps
2 brackets
screws
pin
string
etc.