Q. With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements :- All types of UAVs can do vertical landing.
- All types of UAVs can do automated hovering.
- All types of UAVs can use battery only as a source of power supply.
How many of the statements given above are correct? (UPSC Prelims 2025)
Answer:
None
Notes: The correct answer is
[D] None. Unmanned Aerial Vehicles (UAVs), commonly known as drones, vary significantly in their design, propulsion systems, and flight capabilities.
- Statement 1 (Incorrect): Not all UAVs can perform vertical landing. While Rotary-wing UAVs (like quadcopters) and VTOL (Vertical Take-Off and Landing) fixed-wing hybrids can land vertically, standard Fixed-wing UAVs function like traditional airplanes. They require a runway for a horizontal landing or must be recovered using nets, catapults, or parachutes.
- Statement 2 (Incorrect): Automated hovering is a feature primarily associated with Rotary-wing UAVs. Conventional Fixed-wing UAVs cannot hover; they must maintain a minimum forward airspeed to generate lift and stay airborne. If they stop moving forward, they will stall and fall.
- Statement 3 (Incorrect): While many small consumer drones use lithium-polymer batteries, many professional and military UAVs use alternative power sources. Some are powered by internal combustion engines (using gasoline or heavy fuel), hydrogen fuel cells, or even solar power (like high-altitude long-endurance drones). Hybrid systems that use a gas engine to charge a battery are also common.
Key Categorization:
UAVs are generally classified by their flight mechanism into:
- Fixed-wing: Efficient for long distances but cannot hover or land vertically.
- Single-rotor/Multi-rotor: Excellent for hovering and VTOL but have limited speed and range.
- Fixed-wing Hybrid VTOL: Combines the vertical capabilities of rotors with the efficiency of fixed wings.