China Civil UAV Theory Questions — Questions 336–345

UAV-Q0336. On the current multi-axis flight controller market, the KK flight controller's advantage is

Explanation

Study note: KK is cheap, DJI is not open-source, the rest are open-source. The KK flight controller's advantage is that it is the cheapest, with fewer functions.

UAV-Q0337. On the current multi-axis flight controller market, the MWC flight controller is characterized by

Explanation

Study note: KK is cheap, DJI is not open-source, the rest are open-source. MWC is open-source and based on the Arduino platform, not the Android platform.

UAV-Q0338. On the current multi-rotor flight controller market, the DJI NAZA flight controller is characterized by

Explanation

Study note: KK is cheap, DJI is not open-source, the rest are open-source. The DJI NAZA is a packaged product with closed-source code.

UAV-Q0339. Under current technology, the INCORRECT statement about why fuel engines are unsuitable as multi-axis aircraft power is

Explanation

Biofuel energy density is higher than lithium batteries, so option A is incorrectly stated. Reasons fuel engines are unsuitable as multi-axis power: (1) slow speed regulation, hard to control — multi-axis aircraft control flight by adjusting rotor speeds, and a fuel engine needs a gearbox to change speed, which responds slowly; (2) large size and weight — a fuel engine and gearbox are far larger than a motor and ESC; (3) high risk — carrying a full load of fuel, combustion work, and a complex engine and gearbox structure prone to accidents.

UAV-Q0340. The best touchdown method for landing a tricycle-gear fixed-wing aircraft is

Explanation

A tricycle-gear aircraft has two rear wheels; to ensure landing stability, the rear wheels touch down first.

UAV-Q0341. Light and small UAVs commonly use fixed-pitch propellers whose size is written as X-Y, where Y represents

Explanation

X stands for propeller diameter, Y stands for pitch. Propeller pitch is the distance the propeller advances in one revolution. Pitch affects propulsion efficiency: the greater the pitch, the stronger the thrust, but fuel consumption rises with it.

UAV-Q0342. Which of the following propellers produces the most lift?

Explanation

Study note: when a two-blade prop is an option, choose it. The 18×7 propeller has a large diameter and large pitch, and two-blade props are efficient; it is best on all three counts, so option A produces the most lift.

UAV-Q0343. Ignoring structure, size, safety, and other factors, purely in terms of aerodynamic efficiency, for the same takeoff weight

Explanation

Under the same conditions, a quadcopter has the aerodynamic efficiency advantage, mainly because its propellers are larger in diameter (more lift), its structure is simpler, and it is lighter.

UAV-Q0344. If a multi-axis aircraft's propeller does not match its motor and the prop is oversized, the resulting harm does NOT include:

Explanation

During flight, current flows battery → ESC → motor to do work and spin the propeller. An oversized prop demands greater current, which can damage the ESC and motor through excessive current.

UAV-Q0345. For the same capacity, the lightest battery type is

Explanation

Study note: Ni-Cd has strong memory effect, is cheap, and must not be discharged; otherwise choose lithium batteries. Li-po lithium polymer batteries have the highest energy density and the largest capacity for the same weight.