Member Labs

Stop-Rotor Rotary Wing Aircraft

rotor wing

The Naval Research Laboratory (NRL) has developed a patented system and method of transitioning an aircraft between helicopter and fixed-wing flight modes. The stop-rotor aircraft is capable of both a helicopter mode vertical takeoff and landing (VTOL) and efficient high speed fixed wing flight by flipping the left wing/rotor blade 180 degrees between flight modes. This conversion will take about 1-2 seconds, and simulations indicate altitude deviations of less than 50 feet. Under sponsorship of the Office of Naval Research (ONR), a prototype battery electric aircraft is being developed that is capable of over 30 minutes’ flight duration and a cruise speed of 100 knots. Hybrid power systems could provide much greater duration and range. The 38-inch-long removable payload bay can carry up to 25 lb. Helicopter flight mode testing was conducted in fall 2011. Flight mode conversions are planned for spring 2012.


  • Can operate efficient high speed and long range unmanned aircraft without runway or other large launch and recovery systems such as catapults and nets.
  • Reduced wear and tear compared to a helicopter since rotary wing flight time will typically be minimized.
  • Gas turbine propulsion could enable efficient high subsonic cruise at altitudes not practical with pure rotary wing aircraft.


  • Unmanned aircraft missions that require the flexibility of VTOL combined with high speed and long range.

Click here to view a PDF version of this technology.

For more information, contact Rita Manak, Ph.D., 202-767-3083.

Member Labs