This is a simple foot release mechanism for catapult launching.
 It works by lifting the plane and tow ring up over the vertical 
shaft of a bolt or any sort of rod you use.
The overall length should be 2 to 4 feet, long enough for the plane 
to rest on the front section with a bit of the pedal protruding from the rear. 
It is a simple teeter-totter that lifts the plane and ring off of a stationary rod.
The rod should be slightly bent backwards toward the rear of the pedal.
The rod/bolt should be long enough to cause the pedal to
angle upwards when it releases the bungee.
This causes the pedal to become a ramp. 
The threads on the rear of the shaft should be filed 
smooth, so the ring will slide while under tension.
Don’t leave the bungee stretched and attached to the pedal.
It is up to you to use materials suitable for this launcher. 
It should be built to withstand launching tension of at least 
100 pounds, so you have a safety margin.

NOTE!!!!

A stretched bungee can do a lot of damage if it comes loose!!

Do not use it without at least 25ft. of line from the bungee to the tow ring.
This is the minimum amount necessary to keep the bungee 
from hitting you in the event of a failure.
IT IS NOT ENOUGH TO STOP THE BUNGEE AND A STAKE!!!! 
The line should be #18 braided Mason line, it is rated at 225 pounds.
Make sure you have a good stake in solid ground,
 it is a good idea to have a second stake with a loose line
 to the primary stake for back up. If you have soft or damp 
soil it is a good idea to use a spiral dog leash anchor for a stake, 
these go in deep and have more surface area. Don’t let anyone get
 in the launching path or near the stake. I always hold the 
plane away from my body, out to the side, so I’m not in the 
direct path of the bungee.

You shouldn’t be doing this anywhere near children or crowds!

Always check your connections, tubing, stake, rings etc.
 I always go to the stake for every launch. I inspect the stake, 
grab the connectors and run the tubing through my 
fingers as I lay it out for the next launch. I do a visual inspection 
as well as feeling for nicks or irregularities in the tubing. 
This only takes a few seconds longer and will keep 
you aware of the condition of your equipment..

Here is a simple taping diagram for attaching a hook to a plane.
The taping will spread the loads out sufficiently enough
 to take a lot more pull than you expect. Use a good filament tape 
like "Anchor Brand" or "3M" 
I prefer Anchor because it is very thin and light weight.
The general idea is to wrap a few narrow strips around 
the hook and trail them out to the side and forward at angles 
from the hook, then strap those tapes down with wider 
sections of tape from front to back along the sides of the hook. 
Then you put span-wise strips across the area in front of the hook.
 Leave space between all the primary strips, so the 
final layer will have contact with the surface of the plane.

If your plane is covered with "ultracote" or a standard covering, 
you should apply a layer of packing tape to the hook area first. 
This will spread the load better and provide a stiffer surface for 
the hook to be taped to.
These are basic diagrams and not intended to be exact plans
 for building any launching systems.
You assume all risk involved in building or using any launching system.
If you don’t understand these diagrams, 
you shouldn’t be attempting to build any of it.

Mark Mech and Aerofoam assume no responsibility 
for any misuse or injuries resulting from using any bungee launching system. 
USE AT YOUR OWN RISK!!!