Captain's Table

Mark Austen

2020.01.18 - Flying Over Water

The weather station at the bottom of our field indicated that the wind was from the North-West but only around 3 knots so I decided to take the drone over to Naiad where I could check her moorings and then walk along the footpath beside the river until I was well away from people, vehicles, vessels and structures and take the drone out for a spin.

When I reached the club I found that the wind was a lot stronger than at the bottom of our field and freezing cold. I lit the heater in Naiad and had a cup of tea before I went off downstream for a quick flight.

There are a number of things you do before flying a drone like checking the weather, whether there are any restrictions where you intend to fly and also a visual inspection. This is something all pilots do and involves checking the aircraft for damage and things that are wrong. Although drone pilots are remote operators in that we stay on the ground whilst the aircraft flies, a visual inspection is still required.

Here's what I found:

This is one of the four propellors.

A closer look at one of the blades reveals a small split.

Here is a closer view.

Time to replace the prop. Easy to do and I had 4 spares in my bag, two clockwise rotating and two anti-clockwise.

The ground was very soft and muddy and I could not find a clear space upon which to put the landing pad, so I stamped a bit of grass down and just launched from there. I really need to make a neck strap for the controller so that I can operate two sticks with one hand for the motor startup meaning that I could hand launch the drone. Still I got it up in the air and flew around until my fingers got too cold. I hand caught the drone for landing as that only requires the use of one control stick. Then it was back to Naiad to warm up.

Here is a short clip from the flight.

The main difference between this and my previous flights is that the drone camera had a Neutral Density Filter (ND Filter) fitted for this flight and a number 16, which allows only a sixteenth of the normal light into the camera. It's like putting sun glasses on the lens.

The reason for doing this is that this drone has a fixed aperture of f2.8 and I manually set the ISO to 100 and frame rate to 60 frames per second. Now convention dictates that the shutter speed is numerically twice the frame rate meaning that I needed to set the rate to 1/120 second in order to get the correct 'motion blur' when close to the ground. But these settings will result in a completely over-exposed image and hence the ND Filter. The result was quite good, possibly a little under-exposed when flying away from the sun, but not at all bad.

The clip I have shown above is unedited other than cutting out the bits I wanted to show, there have been not white-balance changes or colour compensation.

When you also consider that there wind was blowing at around 15 knots and gusty, the 3-axis gimbal does an excellent job of keeping the camera stead.