The main problem of flamethrowers is that they are heavy, bulky and cumbersome, so
asked for a light and portable flamethrower capable of 10 minutes flames or more without the need of a combustive backpack.
It works capturing in the air two important gases: oxygen and hydrogen, and mixing them into Oxyhydrogen [link]
a very combustible gas, and firing it at high pressures.
All the mechanism for air capture, elimination of other gases, mixing of O² and H² and pressurization is powered by a high powered battery, located over the grip. One full charged battery can provide a 2 hours of continuous fire cone that can reach 10 to 15 meters long. It also creates electrical sparks in the front of the gun, to light the gas.
Dealing with gas fire is dangerous, and users are not encouraged to use this weapon against strong winds. It also should not be used when wet or underwater, as the water can damage the air capture mechanism.
(modeled in Sketchup, rendered in Twilight, retouched in Photoshop CS4)