The sling is a weapon that uses centrifugal force to apply energy to a projectile that when released from its rotation continues in the direction it was travelling when it was released in the hope that some of that energy will be delivered to a target. The slingshot is a similar weapon that uses stored energy in an elastic, typically rubber, band to apply energy to a projectile that when released continues in the direction it was travelling with the same hope. The sling-slingshot / coil-sling uses a crank to turn a spool that stretches an elastic, typically rubber band; the spool can be a screw that stretches the band to great length into a coil. The spool can have a core that heats and cools. It heats with electicity and cools with liquid gas so rapidly that when the ball is released all the forces that enforce the laws of thermodynamics are simply unleashed.<br><br><br><br>Butane can be used to produce rapid heating-cooling cycles, as it cools when released from its tank and can be ignited instantly. The inside of the spool must be the butane holding tanks, and the outside housing of the device must be the heating element. Hot outside, cool inside. Some thought has to be done on energy transfer. Is it better to have the tank on inside or the outside? Would the heating element be too insulated by the rubber to be in the core? Or is that better? We want to have rapid cooling and rapid heating for repeated shots. It cannot be rapidly cooled with a hot core. But heat will transfer faster to a cold core heating the band when the ambient temperature of the outside of the device is not as cold as the inside. That is unless the entire thing is insulated.