Ground effect — transcript

00:00:00.600 --> 00:00:04.910 Ground effect: why your drone feels lighter close to the ground.

00:00:05.400 --> 00:00:10.601 Up high, the downwash flows freely away. Vortices form at the blade tips,

00:00:10.601 --> 00:00:12.218 creating induced drag.

00:00:12.568 --> 00:00:16.267 Descend to within about one rotor diameter of the surface,

00:00:16.267 --> 00:00:20.217 and the ground disrupts the downwash. Fewer tip vortices form,

00:00:20.217 --> 00:00:21.659 so induced drag drops.

00:00:23.568 --> 00:00:27.527 Less drag means less power to hover. The drone feels lighter,

00:00:27.527 --> 00:00:29.315 and can pop up on take-off.

00:00:31.568 --> 00:00:37.513 But climb above the zone and induced drag returns to normal. Suddenly,

00:00:37.513 --> 00:00:40.946 you need more power just to hold height.

00:00:41.296 --> 00:00:46.573 The trap: a heavy drone may hover fine low down, then struggle to climb out.

00:00:47.296 --> 00:00:52.605 Fixed wings get it too, within one wingspan. Climb too early and drag returns,

00:00:52.605 --> 00:00:54.218 costing speed and lift.

00:00:55.296 --> 00:00:59.117 So test that it can hover and climb comfortably at the planned take-off weight.

00:00:59.117 --> 00:01:00.311 Don't trust a low hover.

00:01:03.296 --> 00:01:07.711 Quick check. As your drone climbs out of ground effect, what happens?

00:01:08.696 --> 00:01:10.681 It needs more power to hold height.