A hand-launched aircraft generally refers to a small fixed-wing UAV or radio-controlled aircraft that takes off when thrown by hand. Common applications include aerial photography, model aircraft training, low-altitude inspection, and educational projects.
Unlike a multirotor UAV, a fixed-wing aircraft generates lift through the airflow over its wings as it moves forward. It does not need multiple rotors to provide continuous vertical lift.
A typical electric hand-launched fixed-wing aircraft consists of four main systems: propulsion, flight control and communication, power supply, and airframe structure. Some models with autonomous flight capabilities also include GPS receivers, barometers, and other navigation sensors. Electrical wiring, signal cables, and mechanical connectors integrate these components into a complete aircraft.
Propulsion System
The propulsion system provides the thrust required for forward flight. It usually consists of an electric motor, an electronic speed controller, and a propeller.
Brushless DC motor
Small electric hand-launched fixed-wing aircraft commonly use brushless DC motors. Outrunner motors are widely used because of their compact construction, relatively high power density, and low maintenance requirements. The motor drives the propeller directly.
Motor sizes such as 2204 and 2206 are found in small UAV and RC aircraft applications. However, their suitability depends on aircraft weight, propeller dimensions, battery voltage, and required thrust. There is no single motor power rating that applies to all aircraft of this type.
The motor is usually secured to a mounting plate or motor mount at the front or rear of the fuselage, depending on whether the aircraft uses a tractor or pusher configuration. In a direct-drive arrangement, no additional gear transmission is required between the motor shaft and propeller.
Electronic speed controller (ESC)
The ESC controls the rotational speed of the brushless motor. It receives throttle commands from the receiver or flight controller and uses internal power switching circuits to control the current supplied to the motor windings.
The ESC is usually installed near the motor. Power wires connect it to the battery, while three phase wires connect it to the brushless motor.
Some ESCs include a battery eliminator circuit (BEC), which converts battery voltage into a lower voltage suitable for powering the receiver and servos.
Propeller
The propeller converts the motor's rotational mechanical energy into thrust. It is an important component affecting propulsion efficiency and aircraft performance.
Common propeller materials include plastic, reinforced nylon, and composite materials. Diameter, pitch, blade count, and material all affect motor load, thrust, and power consumption. Some portable aircraft use folding propellers to reduce storage space.
The propeller must be matched to the motor speed, battery voltage, and ESC current rating. Its diameter and blade geometry should not be selected based on fuselage size alone.
Flight Control and Communication System
This system receives commands from the ground transmitter, processes flight data, and controls the motor and servos. Depending on the aircraft's level of automation, it may use a basic radio control receiver or a flight controller with attitude stabilization and autonomous flight functions.
Flight controller
The flight controller is the main processing unit in an autonomous flight system. It processes sensor data, runs flight control algorithms, and sends commands to the ESC and servos.
Common sensors include:
Three-axis gyroscope: Measures angular velocity around the aircraft's three axes and helps detect changes in attitude.
Three-axis accelerometer: Measures acceleration along three axes and provides data for attitude estimation.
Barometer: Estimates altitude from changes in atmospheric pressure and is commonly used in altitude control.
Magnetometer: Measures the direction of the Earth's magnetic field and provides a reference for heading estimation.
Some flight controllers use STM32-series 32-bit microcontrollers as their main processors. The exact processor depends on the flight controller design.
Basic entry-level RC aircraft may not have a separate flight controller. Instead, the receiver sends control signals directly to the ESC and servos.
Radio receiver and antenna
The radio receiver receives control signals from the ground transmitter and passes the corresponding channel commands to the ESC, servos, or flight controller.
Many RC systems operate in the 2.4 GHz frequency band. The receiver can be installed as a separate unit or integrated into the flight controller.
Antennas are usually positioned inside the fuselage or near the wings. Their placement should account for materials such as carbon fiber, which can affect radio signal propagation. Installation position and orientation should follow the receiver manufacturer's recommendations.
Servos and flight control surfaces
Servos are an important part of a fixed-wing aircraft's flight control system. They move the control surfaces to change the aircraft's attitude and direction.
Elevator: Usually installed on the horizontal tail and controls nose-up and nose-down movement.
Ailerons: Usually installed along the rear edges of the wings and control roll.
Rudder: Usually installed on the vertical tail and controls yaw.
Servos convert electrical commands into mechanical movement. Pushrods, control horns, and hinges connect the servos to the control surfaces.
Some simplified fixed-wing models use only an elevator and rudder, while other models also include ailerons. The control arrangement depends on the aircraft design.
Optional GPS navigation module
Some hand-launched fixed-wing UAVs with autonomous flight capabilities include GPS or BeiDou navigation modules. These modules provide position, ground speed, and movement data.
The flight controller can use this information for waypoint navigation, position logging, and automatic return-to-home functions.
However, a fixed-wing aircraft must maintain sufficient forward airspeed to generate lift. It cannot hold a stationary hover in the same way as a multirotor UAV.
Power Supply System
The power supply system provides electrical energy to the motor, ESC, receiver, flight controller, and servos. Its main components are the flight battery and power management equipment.
Flight battery
Small electric hand-launched aircraft commonly use lithium-polymer (LiPo) batteries. Some models also use lithium-ion batteries.
Battery selection depends on nominal voltage, capacity, discharge rate, weight, and the power requirements of the motor and ESC.
A single LiPo cell has a nominal voltage of 3.7 V. Two cells connected in series provide a nominal voltage of 7.4 V. Capacities of 500 to 1,000 mAh can be used as a reference for some small models, but the actual choice depends on required flight time, peak current, and battery weight.
The battery is usually installed in a compartment inside the fuselage and secured with hook-and-loop straps, retaining bands, or a dedicated battery tray. This prevents movement during flight and helps maintain the correct center of gravity.
Power management and low-voltage protection
The power management system distributes electrical power to the onboard components. Some ESCs include a BEC to supply regulated low-voltage power to the receiver and servos. Other aircraft use a separate power module.
Low-voltage protection may be provided by the ESC, flight controller, or battery management circuit. When the battery reaches a configured voltage threshold, the system can issue a low-battery warning or limit motor output to reduce the risk of over-discharge.
The low-voltage threshold must be selected according to the battery chemistry, cell count, load conditions, and equipment settings. A cutoff value of 3.2 V per cell should not be treated as a universal setting for every battery and flight control system.
Airframe Structure
The airframe supports the electronic components and propulsion system while maintaining the required aerodynamic shape and structural stiffness. Its main parts include the fuselage structure, wing mounting components, and external skin or shell.
Fuselage frame and primary load-bearing structure
The fuselage frame provides mounting points for the motor, battery, flight controller, and other onboard components. It also carries bending, torsional, and impact loads during operation.
Common materials include carbon fiber tubes and plates, engineering plastics, lightweight wood, and foam composite structures.
Carbon fiber offers high specific strength and stiffness, making it suitable for components where low weight and structural rigidity are important. Engineering plastics such as ABS are easier to process and mold.
Some small aircraft use carbon fiber rods with diameters of 6 to 8 mm as local structural members. The actual dimensions depend on the span, load, and structural layout.
Wing mounting structure
The wing mounting structure includes spars, ribs, mounting brackets, connectors, and retaining mechanisms.
The spar carries much of the wing's bending load, while the ribs maintain the airfoil cross-section. Mounting brackets and connectors secure the wing to the fuselage.
Some portable hand-launched aircraft use snap-fit or plug-in wing connections for easier transport and assembly.
Wing installation must maintain left-right symmetry, the correct incidence angle, and secure connections. Incorrect installation can affect the aircraft's center of gravity and flight stability.
Fuselage shell and impact protection
Small hand-launched fixed-wing aircraft commonly use expanded polypropylene (EPP) or expanded polyolefin (EPO) foam for the fuselage and wings. These materials are lightweight and provide a degree of impact absorption, making them suitable for lightweight aircraft launched by hand.
Some models also use injection-molded plastic parts, 3D-printed components, or composite materials for specific structural sections.
The fuselage usually includes dedicated spaces for the battery, motor mount, flight controller, and wiring to simplify installation and maintenance.
Safety Precautions
Propeller safety
Once the motor is connected to the battery, the propeller may start rotating as soon as a throttle command is received. Disconnect the flight battery before checking wiring, adjusting the ESC, or performing maintenance.
When testing the motor and ESC, follow the equipment manufacturer's safety instructions and keep clear of the rotating propeller.
Lithium battery safety
LiPo batteries must be charged with a charger designed for the correct battery chemistry and cell count. Charging should be supervised and performed in an appropriate fire-safe area.
Stop using or charging a battery if it becomes swollen, damaged, unusually hot, or shows abnormal voltage readings. Follow the battery supplier's instructions and local requirements for handling and disposal.
Pre-flight inspection
Before takeoff, check that the wings, tail surfaces, and propeller are securely installed. Confirm that the motor, servos, and receiver wiring are properly connected.
Also check the radio link, control surface directions, and battery mounting. Initial flights and testing should take place in a suitable area that complies with local regulations and is clear of people and obstacles.
Custom Precision Machining
Hand-launched aircraft may contain custom mechanical components such as motor mounts, servo brackets, battery retainers, wing connectors, and electronic equipment housings.
Hansheng Automation provides custom precision machining based on customer drawings and technical requirements. Both one-off prototypes and small-batch production are supported. Machining methods can be selected according to the material, dimensions, geometry, and assembly tolerances of each component.
