Rotary-wing unmanned aerial vehicles (UAVs) are some of the most popular types of drones alongside fixed-wing UAVs. They are also commonly referred to as rotary-blade UAVs and unmanned helicopters.
These types of UAVs enable unmanned systems to accomplish otherwise impossible tasks because of their unique capabilities.
What are rotary-wing drones/UAVs?
Rotary-wing unmanned aerial vehicles (UAVs) are unmanned aircraft that use either one large main rotor (often with an anti-torque device) or multiple rotors all spinning at rapid speeds around a shaft to generate lift and to change direction.
Take note that hybrid fixed-wing/VTOL UAVs will not be included in this article. We have a full post on what they are here.
- How Do Rotary-Wing UAVs Work?
- What Are The Types Of Rotary-Wing UAVs?
- What Are The Differences Between Rotary-Wing And Fixed-Wing UAVs?
- What Are Rotary-Wing UAVs Used For?
- What Parts/Components Make Up Rotary-Wing UAVs?
- What Are The Advantages And Disadvantages Of Rotary-Wing UAVs?
- Rotary-Wing UAV Powerplants/Propulsion Devices
- What Are Some Examples Of Rotary-Wing UAVs?
How Do Rotary-Wing UAVs Work?
Rotary-wing UAVs are unmanned robotic aircraft that have the ability to generate lift using their lifting surfaces (in this case rotors/props/blades) along with their powerplant.
Rotary-wing UAVs use rotors that act as small airfoils spinning at rapid speeds to capture airflow as that air is forced downwards creating a pressure difference that creates a suction effect thus generating lift. The direction the UAV can travel is changed by altering the angle of the frame and/or props.
These types of drones actually use the same principle as fixed-wing UAVs in the way they generate lift. These rotors are used as airfoils just like the wings of a fixed-wing aircraft.
Check out our full post that dives further into how fixed-wing UAVs work, the differences between fixed-wing and rotary-wing UAVs, fixed-wing drone applications, parts/components that make them up, advantages/disadvantages, powerplants used in them and some real examples:
A propeller is a type of fin in this case that acts as an airfoil. The rotor/airfoil is sized and shaped in a way that captures the flow of air as the speed the prop rotates increases thus producing lift.
Air flows faster on the curved top side of the blade than on the flatter underside due to its shape. This causes less air pressure to accumulate on the top of the prop creating a suction that lifts the prop up enabling both unmanned fixed-wing and rotary-wing drones to fly.
In the case of single and twin-rotor UAVs specifically, they can change direction using their main rotor/s which is/are capable of changing the angle of attack/pitch of each individual blade rotating around the centre mast/s.
Each blade can produce a different amount of lift depending on its pitch. Changing the angle of one blade and not the others will result in varied lift forces which will generate different amounts of torque in different directions thus changing the UAVs roll, pitch and yaw.
The anti-torque device controls the UAV’s yaw eliminating the excess forces (torque) generated by the large main spinning rotor.
Multi-rotor UAVs typically do not have these complex systems instead varying the speed that each rotor rotates in a controlled manner that can change the direction of the UAV in flight.
Depending on the number of rotors the multi-rotor drone has, they may also configure the direction the rotor rotates differently.
Some props may rotate clockwise and the opposing props may rotate anti-clockwise to cancel torque generated by each rotor which is why both twin-rotor and multi-rotor UAVs don’t need a tail rotor.
These drones obtain energy to produce thrust from powerplants such as engines, batteries, fuel cells, powered drone tethers among others.
They also incorporate other devices such as propellers that are powered by electric motors.
Check out our full post on drone propellers including the different types, how they work, their different sizes and pitch, their materials, how to choose them and much more.
What Are The Types Of Rotary-Wing UAVs?
There are many different types of rotary-wing UAVs. We have split these up into the primary types that can sum up all the sub-types.
Here are the four main types of rotary-wing UAVs:
- Single-rotor UAVs
- Twin-rotor UAVs
- Multi-rotor UAVs
Check out our full post on the types of rotary-wing UAVs where we dive into what each type is and how they work along with some examples of each:
Monocopters, also called unmanned gyropters, are unmanned aerial vehicles (UAVs) with a single rotor that generate lift by rotating their entire frame’s and do not have an anti-torque device.
They are very uncommon but are built as DIY projects by enthusiasts.
Single-rotor unmanned aerial vehicles (UAVs), often called unicopters, are drones with one large main spinning rotor along with an anti-torque device (often a tail rotor) that produces lift and aids in controlling the UAV in flight.
Single-rotor UAVs can further be broken up according to the types of control systems they use. Some use a multi-bladed tail rotor, some use a ducted fan/fenestron, and some don’t have an anti-torque device at all (NOTAR/no tail rotor).
Check out our full article where we dive into what single-rotor UAVs are along with how they work, the types, differences between all rotorcraft, applications, benefits/drawbacks and examples:
Twin-rotor unmanned aerial vehicles (UAVs), often called bicopters, are drones with two large main contra-rotating rotors that produce lift and aid in controlling the UAV in flight.
These types of UAVs do not need an anti-torque device as the two rotors cancel the torque each generates by rotating in opposite directions.
The types of twin-rotor UAVs include tandem rotor UAVs, transverse rotor UAVs, intermeshing rotor UAVs and coaxial rotor UAVs.
Multi-rotor unmanned aerial vehicles (UAVs), often called multicopters, are drones that use three or more rotors that produce lift and aid in controlling the UAV in flight.
These types of UAVs do not need an anti-torque device either as each blade is spun in different directions depending on the number of rotors on the drone which cancels the torque each prop generates.
The types of multi-rotor UAVs include quadcopters (4 rotors), hexacopters (6 rotors), and octocopters (8 rotors).
What Are The Differences Between Rotary-Wing And Fixed-Wing UAVs?
There are several differences between rotary-wing and fixed-wing unmanned aerial vehicles (UAVs). These differences span from the shape of the aircraft to its performance.
Here are 6 differences between rotary-wing and fixed-wing unmanned aerial vehicles (UAVs):
|The shape of the aircraft
|They typically have a combination of horizontal wings connected to a fuselage with an empennage. Some can also only have a fuselage that acts as the lifting surface.
|They typically do not have fixed wings and the entire aircraft is made up of essentially one large fuselage with either one large rotor at the centre or multiple symmetrical rotors.
|The way lift is generated
|They have rigid or flexible fixed wings that enable the aircraft to generate lift. They typically require a powerplant to increase airspeed. They primarily generate horizontal thrust.
|They can have one or more propeller blades all attached to a centre point that rotates quickly in order to fly. They typically have a small tail rotor used as a counter-torque device. They primarily generate vertical thrust.
|The maximum attainable flight time
|Most have a gliding capability which drastically increases the vehicle’s maximum flight time. If the power stops, the aircraft may still be capable of staying in the air as it quickly glides down.
|They rely solely on a powered rotor to stay aloft and therefore use much more fuel and have a much lower flight time in most cases. If the power stops, the aircraft will not be able to stay in the air.
|The amount they can carry
|They can generally have much higher payloads than rotary-wing drones as they consume much less fuel/power and can therefore last much longer in the air than rotary-wing UAVs.
|They can’t typically have as high a payload as fixed-wing UAVs as they consume much more fuel/power as their rotors support the full weight of the drone which reduces the overall flight time and payload capacity.
|The stability of the vehicle
|They are typically much more stable as there are fewer moving parts compared to rotary-wing UAVs
|They have more moving parts causing the aircraft to vibrate much more affecting stability.
|The space they need to takeoff
|They require short or long runways in order to build up enough speed to takeoff. These runways generally take up a lot of space.
|They require rotors to rotate at a high enough speed/RPM (Revolutions Per Minute) around a fixed axis in order to takeoff vertically. They only need a small area to takeoff.
Take note that hybrid fixed-wing/vertical takeoff and landing (VTOL) UAVs are hybrids between fixed-wing and rotary-wing drones.
These unmanned aircraft typically takeoff using their vertical propellers and transition into forward horizontal flight using their fixed wings.
Check out our detailed post where we dive into what hybrid fixed-wing/VTOL UAVs are, how they work, the different types, applications, parts/components, advantages/disadvantages, and examples:
Related Post: What Are Hybrid Fixed-Wing/VTOL Drones (UAVs)?
What Are Rotary-Wing UAVs Used For?
Here are 5 applications for rotary-wing UAVs:
- Aerial mapping and surveying
- ISTAR (Intelligence, Survelliance, Target Acquisition, and Reconnaissance)
- Crop monitoring
- Search and rescue operations
Check out our full post on rotary-wing UAV applications where we explain what each application entails and how drones are used in them:
Related Post: 9 Awesome Rotary-Wing Drone/UAV Applications Explained
What Parts/Components Make Up Rotary-Wing UAVs?
Rotary-wing UAVs are made up of various parts and components which enable them to function.
They are made up of a fuselage, tail boom, tail assembly/empennage, anti-torque device, swashplate mechanism, powerplant, propulsion devices and often a small tailplane.
The fuselage is the primary body section of the UAV. It usually contains cargo such as passengers and some important internal components.
The tail boom is the structure connected to the back of the fuselage that supports a single and twin-rotor UAV’s tail assembly.
The tail assembly/empennage is the entire tail configuration which includes a fin (vertical stabiliser) that acts vertically and often a horizontal tailplane/stabiliser that acts horizontally.
A tailplane is a small wing typically placed on the tail of both fixed-wing and rotary-wing UAVs that acts as a horizontal stabiliser aiding in controlling the helicopter’s pitch and therefore stability.
The anti-torque device is a small control system (often a small rotor) located at the tail of an unmanned rotorcraft that eliminates the torque generated by the main rotor/s thus controlling the aircraft’s yaw.
Anti-torque devices can be multi-bladed tail rotors, ducted fans/fenestron, and some helicopters don’t use one at all (NOTAR/no tail rotor).
Single and twin-rotor UAVs typically require a swashplate mechanism located at the rotor shaft consisting of a bottom and top independent swashplate (bottom is stationary and top moves with rotor) while being attached together via a bearing.
The top swashplate is attached to the rotor shaft via a driver and is also attached to the blades using control rods.
Swashplate mechanisms are required for the main rotor as they enable the operator to pivot the main rotor in the direction the operates wants to travel.
Multi-rotor UAVs typically don’t require these complex systems, instead just attaching propellers to a motor’s stator (the rod that spins in a motor).
Common powerplants include engines, batteries, drone tethers, fuel cells (FCs) among others (more on this below).
Propulsion devices include propellers that in this case act as airfoils which are types of fins that are sized and shaped in a way that captures the flow of air as the speed the rotor rotates at increases which thus produces lift.
These propellers can be configured in several ways including single systems (single-rotor UAVs), dual systems (twin-rotor UAVs), and multi-rotor systems (multi-rotor UAVs).
Check out our full article on rotary-wing parts/components where we dive into what each is, how they work and the different sub-types of each component (if any):
Related Post: Main Rotary-Wing Drone/UAV Parts & Components Explained
What Are The Advantages And Disadvantages Of Rotary-Wing UAVs?
The rotary-wing configuration is a very old and popular aircraft design in both manned and unmanned systems.
We’ve split up the advantages and disadvantages into their own separate sections.
Rotary-wing drone/UAV advantages
Here are 4 advantages of rotary-wing unmanned aerial vehicles (UAVs):
- They can hover in place for extended periods of time
- They are easier to operate than other types of UAVs in general
- They can takeoff and land in small spaces as they don’t require a runway
- They are much more maneuverable than other types of UAVs at low airspeeds
Rotary-wing drone/UAV disadvantages
Here are 6 disadvantages of rotary-wing unmanned aerial vehicles (UAVs):
- There are many moving parts creating vibrations that can make them less stable
- They are much less efficient than other types of drones giving them short flight times
- They are far slower than fixed-wing UAVs specifically
- They typically have small payload capacities
- They are typically much louder than other types of UAVs
- They are often more prone to being negatively affected by crosswinds which can reduce the effectiveness of their rotor/s
Check out our full post on rotary-wing advantages and disadvantages where we explain several benefits and drawbacks to these UAVs:
Rotary-Wing UAV Powerplants/Propulsion Devices
There are several powerplants/propulsion devices used in rotary-wing UAVs in order for them to function. These devices are used to create thrust for the drone to generate lift and fly.
Here are 5 powerplants/propulsion devices used in rotary-wing UAVs:
- Solar Cells
- Fuel Cells (FCs)
Check out our full post where we dive into several powerplants and propulsion devices currently used in drones. For each power source, we expand on how they work, the different types, the advantages, disadvantages, and real-world examples of drones that use it.
Related Post: How Are Drones Powered? 6 Drone Energy Sources Explained
What Are Some Examples Of Rotary-Wing UAVs?
Here are 11 examples of rotary-wing UAVs:
|A160 Hummingbird (YMQ-18A)
|Pratt & Whitney Canada PW207D Engine
|DPI UAV Systems
|Twin-Rotor (Tandem Rotor)
|Multi-Rotor (4 Props)
|Twin-Rotor (Intermeshing Rotor)
|Shaft Turbine Engine
|Doosan Mobility Innovation
|Multi-Rotor (6 Props)
|Hydrogen Fuel Cell
|Scientific Technical Center (STC) Delta
|JetA1 Single Turbine Engine
|Multi-Rotor (8 Props)
|DPI UAV Systems
|Twin-Rotor (Tandem Rotor)
|Multi-Rotor (4 Props)
If you’d like to discover who the best drone companies are in the world for the consumer, commercial and military drone markets and some fun facts about them, we have a full post on this topic below:
There are actually fewer benefits to drawbacks in reality for this design. However, some of these benefits can be far more important to some compared to the drawbacks.
This is why it is still one of the most popular configurations used in UAVs today.
We hope that you’ve learned more about rotary-wing drones and their importance in the unmanned robot industry.