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?

(a) Only one

(b) Only two

(c) All the three 

(d) None

Ans-d

Explanation

Early UAVs development is generally divided into two separate types, Fixed Wing UAV (FWUAV), and rotorcraft UAV (RUAV). 

FWUAVs typically have longer endurance and thus can reach further than RUAV in a single flight, but require runways for take-offs and landings. 

RUAVs on the other hand, are more manoeuvrable and able to take-off and land vertically without any runway but has much lesser endurance due to their low efficiency in power consumption and low speed.

Hybrid Vertical-Take-Off-Landing (VTOL) aircraft will have the advantages of both FWUAV and RUAV 

Drones, are generally classified as single rotor (helicopter), multi-rotor (multicopter), fixed wing, and fixed-wing hybrid VTOL according to their physical structures.

Single-rotor drones are small-sized helicopters, and fueled or electric types are available. Working with a single blade and fuel offers advantages such as increasing stability and flying longer distances, but it also brings safety risks.

Multicopters are the smallest, lightest, and most widely used drones on the market. Multicopters are divided into models with four engines (quadcopter), six engines (hexacopter), and eight engines (octocopter) according to the number of motors.

Fixed-wing drones: Unlike rotary wings, they use wings like a regular airplane instead of vertical lift rotors to provide lift . In other words, they only need to use energy to move forward. They are much more efficient as they do not use additional power to stay in the air, so they can cover longer distances and scan much larger areas. Gasoline-powered ones can remain in the air for 16 hours or more.

The main disadvantage of a fixed-wing aircraft is that they cannot fly in one spot. Depending on their size, they need a runway or launcher to get them into the air. Fixed-wing also makes launching and landing them much more difficult, as a runway, parachute, or net may be needed for a safe landing again after the flight.

Fixed-wing hybrid Vertical-Take-Off-Landing(VTOL)drone: Fixed-wing hybrid VTOL drones are a new hybrid category that can also take off and land vertically, combining the advantages of fixed-wing UAVs and the ability to hover. 

Fixed-wing hybrid VTOL unmanned aerial vehicles have the advantages of flying vertically and hovering, offering greater versatility than fixed-wing drones and the durability needed to travel long distances with heavy payloads. On the other hand, they could be better in both forward flying and hovering features and the need for specialised personnel in the flight and control of these types of drones is an important consideration.

Their power sources classify drones as battery-powered, gasoline-powered, hydrogen fuel cell, and solar drones. 

Hence none of the statements are correct 

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