China Civil UAV Theory Questions — Questions 163–172

Short version: the map shows position. Textbook p. 43. Map track display provides the remote pilot with UAV position and other navigation information. It includes aircraft navigation information display, track plotting display, and geographic information display. Option analysis: ① Position: navigation information display shows real-time UAV positioning information, onboard positioning sensor equipment status information, UAV navigation information, navigation controller parameters, and mission planning information. ② Flight attitude: part of the integrated flight parameter display, under flight and navigation information. ③ Flight-control attitude: this term does not exist.

Micro UAVs generally use electric propulsion systems. An electric propulsion system is mainly composed of a power motor, a power supply, and a speed control system. Memory point: power supply → ESC → motor. Further reading: the motor speed control system is called the ESC (electronic speed controller).

Study note: choose the option about opening the parachute at high altitude. To make parachute landing more accurate and reduce wind effects, open the parachute at low altitude in the upwind area. Reason by elimination: opening the parachute at high altitude on a windy day makes wind interference on the UAV more pronounced and landing deviation large. Opening the parachute in the downwind area means the wind blows the UAV away from the target landing point, making it hard to land on target. If the main parachute is not disconnected after touchdown, the UAV may be blown away by the wind.

The onboard mission system manages mission equipment and has nothing to do with flight. The onboard remote control receiver receives commands but does not control flight. The onboard navigation and flight control system handles navigation and flight control — the term 'flight control' itself points to the answer.

Study note: two-stroke goes with 2T. 2T engine oil: oil for two-stroke engines, also called combustion oil — it is mixed with gasoline in a certain ratio and burns together with the gasoline. 4T engine oil: oil for four-stroke engines — it lubricates, dissipates heat, and cleans, and does not take part in combustion.

A four-stroke engine burns fuel directly; a two-stroke engine burns a mixture of gasoline and lubricating oil. In a two-stroke engine, air and the fuel-oil mixture enter the engine through the same passage. The mixture must burn in the cylinder to produce power, and it also lubricates and cools to protect engine components.

Flight control subsystem functions: ① UAV attitude stabilization and control [required]; ② completing track control in coordination with the navigation subsystem; ③ UAV takeoff and landing control; ④ UAV mission equipment management and control; ⑤ UAV flight management [required]; ⑥ emergency control [required]; ⑦ information collection and transmission.

The flight control computer should have the following functions: ① attitude stabilization and control; ② navigation and guidance control; ③ autonomous flight control; ④ automatic takeoff and landing control. Easily confused knowledge: the flight control subsystem mainly has the following functions: ① UAV attitude stabilization and control (must have); ② completing track control in coordination with the navigation subsystem; ③ UAV takeoff (launch) and landing (recovery) control; ④ UAV flight management (must have); ⑤ UAV mission equipment management and control; ⑥ emergency control (must have); ⑦ information collection and transmission.

Study note: ground control goes with display, flight control goes with remote control. Textbook p. 45, original definition of flight control. Further reading: Remote sensing means non-contact, long-distance detection technology — generally, using sensors to detect the radiation and reflection characteristics of electromagnetic waves from objects. Remote sensing uses instruments sensitive to electromagnetic waves to detect target objects from far away and without contact. Telemetry means transmitting nearby measured values of an object's parameters to a distant measuring station to achieve remote measurement, and sending the results to a receiving location for recording, display and processing.

Study note: over-rich mixture leads to spark plug carbon deposits. Over-rich mixture combustion in a piston engine causes spark plug carbon deposits. Take driving a car as an example: on heavily congested roads, the vehicle keeps stopping and starting, the engine cannot run at high speed, and fuel or lubricating oil that enters the combustion chamber cannot burn completely; the unburned fuel forms gum under high temperature and oxygen, adhering to engine internal parts, and then forms carbon deposits under high temperature. Poor-quality gasoline contains large amounts of gum, which enters the combustion chamber through the fuel supply system and burns together with gasoline, forming carbon deposits.