Question 69 from UPSC CSE 2025 - Current Affairs (S&T)

Question

With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:
I. All types of UAVs can do vertical landing.
II. All types of UAVs can do automated hovering.
III. All types of UAVs can use battery only as a source of power supply.
How many of the statements given above are correct?

IASCODEX · Accepted Answer

Correct Option: D. None

Strategy: - **Statement I:** Assesses vertical landing capability. This is false, as fixed-wing UAVs require runways or nets for landing, unlike rotor-based types.
- **Statement II:** Asserts automatic hovering for all UAVs. This is also false--only rotor-based UAVs can hover, while fixed-wing types cannot.
- **Statement III:** Suggests all UAVs solely use batteries. This is incorrect, as long-range or military UAVs often employ fuel engines for extended endurance.
Since none of the statements are universally true across all UAV varieties, the correct count is zero.

Key Info: Unmanned Aerial Vehicles (UAVs), commonly called drones, are aircraft operated remotely or autonomously, without an onboard human pilot. Their applications include surveillance, mapping, logistics, agriculture, aerial photography, and military operations.

## Types of UAVs
*   **Fixed-wing:** Have airplane-like wings and require runways or launches for takeoff and landing. They cannot hover or perform vertical take-off/landing (VTOL). Examples include Predator and Heron.
*   **Rotary-wing/Multirotor:** Include quadcopters, hexacopters, and octocopters. Capable of VTOL and hovering due to spinning rotors. Widely used in commercial and hobby applications.
*   **Hybrid VTOL:** Combine features of fixed-wing and rotary systems, offering VTOL capabilities and longer flight duration (e.g., certain military or commercial delivery drones).

## Landing and Hovering
*   VTOL capability and hovering are restricted to rotary-wing and hybrid designs. Fixed-wing drones must land horizontally and cannot hover.

## Power Sources
*   **Battery:** Most small to medium-sized drones use lithium-polymer or lithium-ion batteries. They are limited by low energy density and short flight duration.
*   **Liquid fuel (petrol, diesel, aviation fuel):** Used by larger, long-endurance UAVs for longer range and heavier payloads. Common in military and survey drones (e.g., General Atomics MQ-9 Reaper).
*   **Hybrid propulsion:** Some UAVs combine batteries and fuel engines for mixed power.

## Conclusion
No single feature (vertical landing, automated hovering, battery-only power) is universally present across all UAV categories. UAV technology is diverse, and operational capabilities depend on design and intended use.

IASCODEX · Answer

Option A: Only one

IASCODEX · Answer

Option B: Only two

IASCODEX · Answer

Option C: All three