Flying drones throughout the winter is a necessity to maximise available time for ongoing surveys. Often, conditions in the winter can be perfect for surveying but there are some issues that you should be aware of when flying yourself or hiring in an operator. So here are our top 4 winter drone considerations.
The lithium polymer batteries in drones do not cope well with cold conditions. Under some circumstances you can lose 30-50% of your flight time. Generally, batteries need to be kept at least 20oC to function effectively. The cold can also have an impact on the battery life of ground equipment as well. Some types of drone will not allow you to take off if the battery temperatures are too low, but others will allow you to take off, but potentially the drone could fail if power demand increases.
Aside from the obvious lack of daylight hours in the winter, the winter sun is much lower even at midday. As a result, working can be more difficult due to the fact that the sun can be low in your eyeline when flying. Often the ground lighting in winter can be an issue, with relatively bright skies and darker ground leading to issues with the camera coping with contrast. Particularly when surveying in the winter for mapping and modelling, harsh shadows can cause very dark areas and loss of detail in images.
Generally, when we are outside in the winter we move around a lot and wear gloves to keep warm. When flying a drone we tend to stand very still and hands are relatively exposed. In terms of health and safety, it’s really important to be aware of how cold you are getting and to take breaks regularly to warm up and ensure your hands are working properly!
When moving drones between warmer and colder environments it is really important to acclimatise the camera. Even at different heights the air temperature and humidity can be different. In an early creative wind turbine shoot, the drone got very cold on the ground and, when it got to about 30m up, the lens instantly fogged as the air higher up was a bit warmer. You may also get a lot of condensation on your kit when you get back indoors.