I have just ordered one of these bungee ramps from HK and will post some videos in May or June, as it has to be shipped to the UK from the USA.
You tension the bungee by fixing one end onto a stake, pull the bungee tight and hook it to the pedal using a 1.5m length of cord, then use another cord from the end of the bungee to a hook under your wing.
This kit costs $23.10 its PRODUCT ID is : 310000137-0 Self Assembly Pedal Operated Bungee Launch System/Ramp for FPV/Glider and EDF Models - Hand launching models can be a tricky business and most flyers have had it all go wrong for them at some point, this great launch system is easy to transport & field assemble and allows you to launch totally solo with the peace of mind of adequate airspeed every time for a succesful launch, everything you need is included!
Dimensions once Assembled:
Ramp Length - 1060mm
height at rear - 240mm
height at front - 460mm
width of launch rails - 470mm
Ramp - GF Tubing with Plastic Joiners
Foot Launch System - Ply with surgical rubber hose (2 metres)
HK offer two types of silicon tubing;
Silicon rubber Bungee Cord stretches to 6 times its original length and is light weight giving a consistant pull, great for gliders and EDF jets of up to 3kg.
Outside diameter: 6mm
Inside diameter: 4mm
PRODUCT ID: RLT-6x4-10m
Silicon rubber Bungee Cord stretches to 6 times its original length and is light weight giving a consistant pull, great for gliders and EDF jets of up to 5kg.
Outside diameter: 8mm
Inside diameter: 5mm
PRODUCT ID: RLT-8x5-10m