3DR Solo User Manual - 3.5  Propellers

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3.5  Propellers

To avoid hazardous contact with Solo’s high-speed propellers, always power off Solo before handling Solo or 

the propellers. When prompted to start motors before takeoff, always ensure that the propellers are clear of any 

obstructions and at least 20 feet away from any people, animals, or property before activating. Do not touch moving 

propellers or approach Solo while the propellers are spinning.

After landing or returning home, Solo will automatically detect the landing and stop the motors. Do not approach 

Solo until the propellers stop spinning, and always power off Solo before picking it up.

3.6  GPS

Solo requires an active GPS signal for flight. After powering on, Solo can take up to 5 minutes to acquire a strong 

GPS lock. Always choose a flying location with a clear view of the sky to improve GPS signal strength. The following 

requirements define a GPS lock:

•  Reported horizontal position accuracy 

< 16 ft. (5 m)

•  Reported speed accuracy   

< 2 mph (1 m/s)

•  Number 

of 

satellites 

     ≥ 

6

•  Difference between GPS and inertial navigation vertical velocity 

< 2 mph (1 m/s)

If satellite coverage drops beneath a reliable threshold during flight, Solo will automatically switch to FLY:Manual 

mode. This mode does not provide the flight stabilizing GPS functionality, but it still allows you to retain control of 

Solo. 

3.7  Home Position

Solo’s home position is the latitude and longitude coordinates of the launch point used by the autopilot as the 

end point of a return-home command. The autopilot saves the home position at the location where the motors are 

started only after achieving GPS lock. The location of the home position depends on GPS signal strength and is 

usually within 1 to 2 meters of accuracy. Always take off from an open location with a clear path for Solo to return 

home safely. For home position safety in advanced mode, see Section 7.4.

3.8  Altitude Limit

Always fly at appropriate altitudes for your flying location and local regulations. Solo cannot avoid obstacles on its 

own, so always select altitudes that avoid any obstacles, such as trees, buildings, and power lines.

Solo includes a safety fence enabled by default at 150 ft. (46 m). If Solo reaches the altitude limit, Solo will stop 

ascending and limit throttle input to stay below the altitude limit. FAA regulations mandate a maximum altitude of 

400 ft. to avoid potential conflicts with manned aircraft and represents a safe line-of-sight altitude. 

Spinning propellers can cause serious injury. Never touch moving 

propellers or place any objects in the way of the propeller arcs while 

Solo is powered.

400 ft

400 ft