Other methods of recovering drones include net systems suspended between poles and attached to a system of purchase lines and shock absorbers. Some gas-powered systems use a pyrotechnic charge, which again limits their use due to certain regulations. Gas-powered systems exert a lot of force, but due to the pressurization, cannot be transported on commercial aircraft. Spring systems are simple and lightweight, but are limited in the amount of energy that can be stored. They are deployed by opening a hatch and letting the wind catch a smaller parachute that drags out the main parachute deployment bag.īallistic UAV parachutes depend on either a mechanical spring or a gas such as CO2 to deploy the parachute. Passive systems are usually used on fixed-wing UAVs that are in constant forward flight.

UAV parachutes may be deployed either passively or ballistically. Although they are the quietest and cheapest solution, they are limited to smaller UAVs. The cord may be stretched manually or by means of an electric motor. Like pneumatic UAV catapults, hydraulic UAV launchers also require a power supply to operate.īungee-powered UAV catapults are simpler than hydraulic or pneumatic launchers, using energy stored in elastic cords. Pumping the oil causes the piston to compress the case, which stores energy for launching the UAV. Hydraulic UAV catapults use a two-compartment cylinder containing oil and compressible gas separated by a piston. A compressor is needed to pressurize the gas, requiring a power supply and potentially being bulky and difficult to transport. Pneumatic catapult launchers use compressed air or other gases to accelerate a launching cradle along the launcher. UAV catapult launchers may be pneumatic, hydraulic or bungee-assisted. The smallest and most lightweight UAVs can be thrown by hand, or launched with a handheld device, whereas larger aircraft will require a fixed rail launcher.

Various methods can be employed that do not require the use of a fixed runway or large cleared area. Fixed-wing UAVs generally need to be accelerated to a minimum controllable airspeed before achieving takeoff.

Catapult launcher