# Tailsitter VTOL
A Tailsitter VTOL takes off and lands on its tail, but flips into the fixed-wing orientation for normal flight. The tailsitter rotors are permanently fixed in position for forward flight.
Tailsitters are typically mechanically less complex than other types of VTOL, and hence may be less expensive to build and maintain. However they are aerodynamically more complex, and can be harder to tune and fly for hover and transition, particularly in windy conditions.
# Tailsitter Airframes
- Forward flight more efficient
- Hover harder to fly, particularly in wind
- Hover and transition harder to tune
- More compact form factor
- Hover mode easier to fly and more stable
- Less compact form factor (harder to transport)
- "X" and "+" rotor configurations are supported (see Airframe Reference)
Duo Tailsitters are generally more efficient in cruise flight (4 smaller propellers are less efficient than 2 larger ones) and physically more compact. However as they are aerodynamically much more complex in hover mode, they are much harder to tune for both hover and transition. Quad tailsitters are easier to fly in hover mode, and more stable in windy conditions.
VTOL setup and flying are covered in the VTOL parent topic.
The instructions are essentially the same for all VTOL. The main frame-specific differences are the motor wiring (see VTOL Duo Tailsitter and VTOL Quad Tailsitter), and some aspects of tuning the configuration.
# Build Logs
Step-by-step guides of how to set up PX4 on tailsitter frames are listed below:
We recommend that you also review build logs for other PX4 VTOL, and Copter vehicles (most of the setup is the same).
This section contains videos that are specific to Tailsitter VTOL (videos that apply to all VTOL types can be found in VTOL).
TBS Caipiroshka - Tailsitter takeoff (close up), hover, level flight, transitions.
PX4 Tailsitter prototype - Tailsitter takeoff, transition, landing.
Skypull (opens new window) Tethered quad tailsitter (promotional video)
UAV Works VALAQ Patrol Tailsitter (opens new window) - Tailsitter takeoff, transition, landing.