The successful launch of UAVs (unmanned aerial vehicles) is crucial and often pose significant challenges. To achieve takeoff most fixed-wing UAVs need to be accelerated to a minimum controllable airspeed.
Large fixed-wing UAVs are typically confined to taking off from and landing on a runway with adequate length. These runways can be constructed on suitable ground or on the deck of an aircraft carrier.
Multirotor and Vertical Takeoff and Landing (VTOL) UAVs have clear advantages when it comes to launch and recovery. These unmanned aerial systems require minimal space, and in many cases, no additional equipment is needed for takeoff, except a flat and stable surface to launch from and return to. Hybrid fixed-wing UAVs combine benefits of VTOL with a fixed-wing design.
sUAS and medium-sized fixed-wing UAVs aren’t restricted to conventional runways, providing more flexibility in operational environments. Many small lightweight drones can be launched by hand. Others will require a fixed rail launcher and catapult system.
UAV Catapult Launchers
UAV catapult launchers may be pneumatic, hydraulic or bungee-assisted:
Bungee UAV Launching System SCL-1A by Ukrspecsystems
Pneumatic UAV launchers use compressed air or other gasses to accelerate a launching cradle along the launcher. A compressor is needed to pressurize the gas, requiring a power supply and potentially being bulky and difficult to transport.
Hydraulic UAV catapults use a two-compartment cylinder containing oil and compressible gas separated by a piston. Pumping the oil causes the piston to compress the case, which stores energy for launching the UAV. Like pneumatic UAV catapults, hydraulic UAV launchers also require a power supply to operate.
Bungee-powered UAV catapults are simpler than hydraulic or pneumatic launchers, using energy stored in elastic cords. The cord may be stretched manually or by means of an electric motor. Although they are the quietest and cheapest solution, they are limited to smaller UAVs.
Vehicle Drone Launchers
If a surface is available that is unsuitable for the smaller, more delicate landing wheels of a UAV (due to long grass, gravel, unevenness or other obstructions), but sufficient for a larger, more durable vehicle such as a truck to be driven along it, a launch may be possible from that vehicle.
With vehicle-based military drone launchers the UAV is typically held in a fixed cradle on top of the truck, angled upwards at an angle that gives maximum lift. When the truck has been accelerated to takeoff speed, the cradle is released and the UAV lifts directly upwards into flight.
UAVs may also be launched from the deck of a ship using catapult launchers, or from larger aircraft in flight.