Tilt-rotor hybrid fixed-wing/vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs) are some of the most popular types of hybrids alongside quadplanes.
What are tail-sitter UAVs?
Tail-sitter unmanned aerial vehicles (UAVs) are hybrid fixed-wing/VTOL drones that can takeoff and land vertically while resting the tail of the aircraft on the ground and can transition to horizontal flight by rotating their entire frames in flight.
Take note that proprotors are propellers that are used for both vertical and horizontal flight.
How Do Tail-Sitter UAVs Work?
Tail-sitter UAVs are types of hybrid fixed-wing/VTOL UAVs.
Check out our full article on what hybrid fixed-wing/VTOL UAVs are where we dive into how they work, their types, applications, parts/components, advantages/disadvantages, and some examples:
Related Post: What Are Hybrid Fixed-Wing/VTOL Drones (UAVs)?
Tail-sitter UAVs incorporate features found in both fixed-wing UAVs and rotary-wing UAVs, blending them together into one single design.
To fully understand how they work, we first have to look over how both fixed-wing UAVs and rotary-wing UAVs work.
Fixed-wing UAVs use wings/airfoils that are sized and shaped in a way that captures the flow of air as the aircraft’s airspeed increases which thus produces lift. We go into more detail in our article on what fixed-wing UAVs are.
Rotary-wing UAVs use one large main spinning rotor (typically with an anti-torque device/tail rotor) or multiple smaller rotors all spinning at a rapid speed. The propellers act as small airfoils capturing airflow and generating lift.
The direction of the UAV can be changed by altering the angle of the frame thus changing the angle of the prop/s in the process.
Tail-sitter UAVs have a unique way of transitioning from vertical to horizontal flight.
Instead of deactivating certain features (like quadplanes) or using a mechanism to rotate a certain part of its body (tilt-rotor UAVs and tilt-wing UAVs), tail-sitter UAVs rotate their entire frame’s horizontally for the transition to horizontal flight.
Tail-sitter UAVs takeoff and land on the tail of the aircraft using proprotors or engines and rotate their entire frame’s horizontally in flight for cruising with their fixed wings.
Some can use a technique known as thrust vectoring where the drone can control the direction of the thrust that is expelled from its engine to move around thus changing the direction the drone flies.
They are different from other types of hybrid fixed-wing/VTOL UAVs in shape and in the way they transition from vertical to horizontal flight.
Check out our full post on the types of hybrid fixed-wing/VTOL UAVs:
Related Post: Types Of Hybrid Fixed-Wing/VTOL UAVs Explained (+Pictures)
What Are Tail-Sitter UAVs Used For?
Here are 5 applications for tail-sitter UAVs:
- Search and rescue operations as they can land in tight spaces while still covering large areas
- Surveillance operations of any kind to survey large areas for long periods of time
- Ocean surveys
- Long pipeline inspections
- Crop monitoring
These are some common applications that are beneficial to these types of UAVs as they can both hover in place and can cruise for extended periods of time.
We have a full article that goes into applications for fixed-wing unmanned aerial vehicles (UAVs) and applications for rotary-wing unmanned aerial vehicles (UAVs).
What Parts/Components Make Up Tail-Sitter UAVs?
Tail-sitter UAVs are typically made up of a fuselage, wings, and a propulsion system.
The wings typically include control surfaces such as ailerons and flaps to aid in controlling the vehicle’s pitch and roll.
Tail-sitter UAVs may have their wings and a dual tail fin fused together giving the effect that they may have four large mainplanes.
There are different types of tail assemblies used in UAVs that we have explained in our article on the types of fixed-wing UAVs.
Typical components include a transmitter, receiver, servos, lights, inertial navigation system (INS), electronic speed controllers (ESCs), and flight controller.
The propulsion system can be made up of a powerplant such as a battery, an engine, fuel cell (FC), solar power etc.
Propellers are devices used for propulsion. They can be used for both vertical and horizontal flight.
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 types, advantages/disadvantages, and real examples of drones that use it.
Related Post: How Are Drones Powered? 6 Drone Energy Sources Explained
We have a full post that goes into the main fixed-wing UAV parts and components and the main rotary-wing UAV parts and components.
What Are The Advantages And Disadvantages Of Tail-Sitter UAVs?
The advantages and disadvantages of tail-sitter UAVs include mixtures of the advantages and disadvantages for both fixed-wing UAVs and rotary-wing UAVs.
There are many benefits and drawbacks to fixed-wing unmanned aerial vehicles (UAVs) as well as benefits and drawbacks to rotary-wing unmanned aerial vehicles (UAVs).
Tail-sitter UAV advantages
Here are 5 tail-sitter UAV advantages:
- They do not require sometimes complex and heavy transition mechanisms like other types of hybrid fixed-wing/VTOL UAVs
- They can efficiently fly for long distances reducing the number of times they need to land and expanding the area they can cover
- They can reach very high altitudes compared to basic rotary-wing UAVs
- They enable the drone to benefit from the advantages of both fixed-wing and rotary-wing UAVs
- They can hover in place for extended periods of time
Tail-sitter UAV disadvantages
Here are 4 tail-sitter UAV disadvantages:
- They typically cost much more compared to basic configurations due to the added feature enabling them to make the vertical to horizontal flight transition
- The transition between vertical to horizontal flight causes the UAV to lose altitude
- They are often quite difficult to control during landings
- They is typically a learning curve to operating these types of UAVs
Check out our full article on the advantages and disadvantages of hybrid fixed-wing/VTOL unmanned aerial vehicles (UAVs):
Related Post: 11 Hybrid Fixed-Wing/VTOL UAV Advantages & Disadvantages
What Are Some Examples Of Tail-sitter UAVs?
Here are 8 examples of tail-sitter UAVs:
| Name | Manufacturer |
| X PlusOne | Xcraft |
| Swing | Parrot |
| WingtraOne | Wingtra |
| Quantix Recon | AeroVironment |
| Marlyn | Atmos |
| V-BAT 128 | Martin UAV |
| SkyTote | AeroVironment |
| X2Q | Xcraft |
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:
Related Post: Top Drone Companies/Manufacturers In The World [History, What They Offer, Popular Drones And More]
Conclusion
Several manufacturers have been testing these types of UAVs creating prototypes for proof of concept and some have been commercially successful.
We highly recommend you check out our main article on what hybrid fixed-wing/VTOL UAVs are to learn more about these incredible types of drones.
