Setting Up a VTOL Vehicle with PX4

VTOL (Vertical Take-Off and Landing) aircraft combine the hover capability of a multicopter with the speed and range of a fixed-wing plane. PX4 supports three distinct VTOL architectures — standard VTOL (quadplane), tailsitter, and tiltrotor — each with different mechanical designs, transition behaviors, and tuning considerations. This guide explains how each type works, how to wire and configure them, and what to expect during the multicopter-to-fixed-wing transition phase. VTOL vehicles offer significant operational advantages:

Flexible deployment: take off and land vertically in confined spaces, then cruise efficiently over long distances.
Hovering capability: hold a stable hover for photography, structural inspection, or target tracking.
Fixed-wing range and speed: carry more payload further than a multicopter on the same battery.

VTOL types

Standard VTOL (quadplane)
Tailsitter
Tiltrotor

A standard VTOL uses entirely separate propulsion systems for hover and forward flight. Dedicated multicopter rotors provide vertical lift during takeoff, landing, and hover. One or more pusher or puller motors on the fixed-wing airframe provide forward cruise thrust. The two propulsion systems do not interfere mechanically, making this the easiest VTOL type to build and tune.Airframe ID: 13000 — Generic Standard VTOLKey VT_TYPE value: 2Advantages:

Dedicated actuators for each flight regime — easiest to control
Hover rotors can be electric while the cruise motor uses a fuel engine for very long endurance
Most forgiving flight behavior during transitions

Disadvantages:

Additional weight from duplicate propulsion systems
Hover rotors create parasitic drag during forward flight, reducing cruise efficiency

Known vehicle builds: Vertical Technologies Deltaquad, FunCub QuadPlane, Volantex Ranger Ex QuadPlane

Standard VTOL is the recommended starting point if you are new to VTOL builds. The separated propulsion systems make failures easier to diagnose and the transition behavior more predictable.

A tailsitter takes off and lands balanced on its tail in a vertical orientation, then pitches the entire vehicle forward to enter fixed-wing flight. The same rotors that provide hover thrust become the forward cruise propellers — there is no separate pusher motor. This design is mechanically simple but places higher demands on attitude control during the transition.Airframe ID: 13200 — Generic VTOL TailsitterKey VT_TYPE value: 0Advantages:

Mechanically simple — minimal actuator count
Compact form factor with no tilting mechanisms or extra motors
Lower empty weight compared with standard VTOL for the same rotor count

Disadvantages:

Sensitive to wind during hover (vehicle balanced vertically on tail)
Efficiency tradeoff — same rotors serve both hover and cruise, optimized for neither
Transition attitude maneuver is more complex to tune

Known vehicle builds: WingtraOne, TBS Caipiroshka, UAV Works VALAQ Patrol

A tiltrotor mounts its motors on mechanical tilting mechanisms that rotate approximately 90° between hover and forward flight orientations. In hover the rotors point upward like a multicopter; in cruise they point forward like conventional airplane propellers. This gives better cruise efficiency than a standard VTOL (no parasitic drag from idle hover rotors) while maintaining more hover control authority than a tailsitter.Airframe IDs: 13030 — Generic Quadplane VTOL Tiltrotor, 13100 — Generic VTOL TiltrotorKey VT_TYPE value: 1Advantages:

Better cruise efficiency than standard VTOL — no drag from separate hover motors
More hover control authority than tailsitters due to dedicated tilt servos
Can achieve a better performance trade-off between the two flight regimes

Disadvantages:

Mechanically complex — tilting mechanisms add weight and potential failure points
More parameters to configure: tilt servo travel, speed, and transition timing

Known vehicle builds: E-flite Convergence, Firehawk Tiltrotor

How PX4 handles transitions

The transition between multicopter (MC) mode and fixed-wing (FW) mode is managed automatically by PX4. The sequence depends on the VTOL type. Forward transition (MC → FW) — Standard VTOL and Tiltrotor:

The pusher or cruise motor spools up to build forward airspeed.
As airspeed rises above VT_ARSP_BLEND, PX4 begins blending hover and fixed-wing control authority.
Once airspeed exceeds VT_ARSP_TRANS, PX4 completes the transition, stops the hover rotors, and hands full control to the fixed-wing controller.

Forward transition (MC → FW) — Tailsitter:

The entire vehicle pitches forward from vertical to horizontal.
The rotors — now pointing rearward — generate forward thrust.
Fixed-wing controllers take over once the vehicle stabilizes in the horizontal attitude.

Back-transition (FW → MC):

The aircraft decelerates below the back-transition airspeed threshold.
MC controllers re-engage and provide a controlled vertical descent for landing.

Key transition parameters:

Parameter	Description
`VT_ARSP_TRANS`	Airspeed at which the forward transition completes and FW mode activates
`VT_ARSP_BLEND`	Airspeed at which blending between MC and FW control begins
`VT_F_TRANS_DUR`	Maximum time allowed for a forward transition before PX4 aborts
`VT_B_TRANS_DUR`	Maximum time allowed for a back-transition
`VT_TRANS_MIN_TM`	Minimum duration the transition must run before it is allowed to complete

Always install an airspeed sensor on VTOL vehicles. PX4 depends on airspeed data during transitions to determine when it is safe to switch between MC and FW controllers. Operating without an airspeed sensor greatly increases the risk of a failed or uncontrolled transition.

Assembly notes

VTOL vehicles share the same core assembly steps as multicopters and fixed-wing aircraft, plus a few additional considerations:

Flight controller: any standard Pixhawk-series controller (Pixhawk 6X, CUAV V5+, Holybro Durandal) handles all VTOL types. The VTOL logic runs entirely in software — no special hardware is required.
Airspeed sensor: required. Connect to the I2C port. See the fixed-wing guide for wiring details and parameter configuration.
Motor output priority: map hover rotors to FMU PWM outputs first for lowest latency. Map the pusher or cruise motor and any tilt servos to remaining outputs.
Tilt servos (tiltrotor only): wire tilt servos to PWM outputs and assign them using CA_SV_TL_COUNT and individual CA_SV_TLx_* parameters in the Actuators configuration.

For standard VTOLs, you can use a fuel-powered combustion engine for the forward flight motor while using electric hover rotors. This hybrid approach is used by commercial long-endurance platforms to achieve flight times of several hours.

Setup workflow

Select a VTOL airframe

In QGroundControl, go to Vehicle Setup > Airframe and select your VTOL type from the Standard VTOL, Tiltrotor, or Tailsitter groups. Click Apply and Restart to load the ROMFS parameter defaults.

Configure actuators

Open Vehicle Setup > Actuators. Assign hover rotors, the forward or cruise motor, control surfaces, and (for tiltrotors) tilt servos to the correct flight controller outputs. Verify motor spin directions match the airframe diagram.

Calibrate sensors

Complete the full sensor calibration sequence: accelerometer, gyroscope, compass, and airspeed. Perform the airspeed calibration outdoors at zero wind for the most accurate offset measurement.

Set transition parameters

Set VT_ARSP_TRANS to approximately 1.3× the fixed-wing stall speed of your aircraft. Set VT_F_TRANS_DUR long enough for your forward motor to build the required airspeed from a hover. A value of 15–25 seconds is a common starting range for mid-size platforms.

Test MC mode first

Fly in multicopter mode only — do not initiate a transition yet. Verify stable hover, correct attitude response in all axes, and position hold behavior. Resolve any MC tuning issues before attempting transitions.

Test transition in a safe environment

Initiate the first MC-to-FW transition at altitude (at minimum 30 m AGL) over open terrain. Have a safety pilot ready to take manual control. Verify the transition completes cleanly within VT_F_TRANS_DUR.

Tune fixed-wing mode

After a successful transition, fly in fixed-wing mode and tune TECS parameters — airspeed targets, climb rate, and time constants — as you would for a conventional fixed-wing aircraft. See the fixed-wing guide for TECS tuning details.

Motor and servo mixing

PX4 uses a geometry-based control allocation matrix to mix roll, pitch, yaw, and thrust commands into individual motor and servo outputs. You do not need to write mixing files manually — the CA_* parameter system handles this based on the rotor positions and surface assignments you configure in the Actuators page. For a standard VTOL, the mixing works as follows:

In MC mode: hover rotors receive differential thrust commands for roll, pitch, and yaw. The forward motor is idle.
In FW mode: control surfaces receive aileron, elevator, and rudder commands. The forward motor receives throttle commands. Hover rotors are stopped or slowly windmilling.
During transition: both systems operate simultaneously with blended authority, progressively shifting from MC to FW control as airspeed builds.

Getting Started

Vehicle Setup

Configuration

Flight Modes

Simulation

Setting Up a VTOL Vehicle with PX4

VTOL types

How PX4 handles transitions

Assembly notes

Setup workflow

Motor and servo mixing

Build docs developers (and LLMs) love

Getting Started

Vehicle Setup

Configuration

Flight Modes

Simulation

Documentation Index

​VTOL types

​How PX4 handles transitions

​Assembly notes

​Setup workflow

​Motor and servo mixing

Build docs developers (and LLMs) love

VTOL types

How PX4 handles transitions

Assembly notes

Setup workflow

Motor and servo mixing