Planning for high winds

Once you’ve verified the forecast, you can then plan your flight. When making a flight plan in high wind conditions it is important to take care of the following;

  • To ensure a more constant frontal overlap, it is preferable (but not essential) to position Marlyn’s flight lines at a 45 degree offset to the wind direction as shown.
  • It is important to note that Marlyn returning to home on a windy day will consume more battery than on a calm day if the drone is travelling into the wind. Therefore, if planning to use a 20% battery RTH safety setting, position Marlyn’s take-off and landing location downwind from the flight area.  

Planning for High Winds: Take-off Location

When planning a take-off and landing location in high winds, it is advised to take off in an open field or large sheltered area. Avoid operating on the downwind side of a hill, sand dune, low building, etc, as winds flowing over these objects tend to accelerate (shown below in blue), causing a region of fast-moving wind at altitude, and also causing an area of unpredictable and turbulent wind at ground level (shown below in green).

These 2 phenomena can cause an issue for Marlyn in 2 ways;

a)    The area of accelerated wind can be up to 50% higher than the ambient wind speed. If this causes Marlyn to be flying in an area above the maximum wind tolerance, it is possible that Marlyn can drift from its position above the home location or even prevent the drone from reaching this position at all.

b)    Since Marlyn must always be pointed into the wind in helicopter mode, the area of turbulent wind can cause the wind direction and strength to behave unpredictably, which can make it more difficult for Marlyn to point into the wind and maintain its position over the home point. 

If either of these situations is encountered unexpectedly in flight, it is best practice to place the aircraft into Manual Flight, climb above the region of air which is affected by the hill/building/etc. and land the drone in a calmer spot. 

Planning for High Winds: Checklist

During the segments of the checklist when no batteries are inserted, Marlyn's weight is reduced, sometimes causing the wind to push Marlyn along the ground. In this case, Marlyn will either slide across a tarmac or slick surface, or tip over on an undulating or rough surface.

Therefore it is good practice before a flight in high winds to rotate Marlyn 90 degrees so that its wings are pointing parallel to the wind direction as shown below. This will reduce the surface on which the wind can act and therefore reduce the chance of Marlyn slipping or tipping over.