Sunset Formation Flight

[Guest davidh10]

Late last week after some more modifications to my camera mount, I was keen to take it for a fly to check if the stability was improved. As it happened, the CFI was up for a formation flight and it looked like we might be in for a good sunset.

 

One of the key reasons for purchasing the camera was to film our group and formation activities. While the CFI has captured video on several flights and during training, using a GoPro camera, the very wide angle of the lens provides a distorted perspective of distance. While that is great for filming the landscape over which you are flying, and good for reviewing formation training flights, it does not convey an accurate representation of the close formation work. For this reason, I purchased a conventional digital video camera, which at its wide angle end of the range is equivalent to a 43.5mm focal length lens for a 35mm SLR. Not being a really wide angle, presents its own challenges. Every bump and vibration has a more significant impact on the image and its watchability. In addition, it is frequently necessary to re-aim the camera at the desired scene, particularly where aircraft are changing relative positions. You can see evidence of this latter issue in the video, where I have had to adjust the camera aiming direction several times during the flight.

 

Flying formation requires a lot of concentration of attention, particularly for those flying as "wingman" and for the "lead pilot", who isn't necessarily in the "lead aircraft". During this flight, I was "lead pilot", so in addition to station keeping, directing the flight, scanning for other traffic and making radio calls, I did occasionally find a moment to re-direct the camera direction. After take-off and leaving the circuit area, we communicate air-to-air on a private channel and monitor CTAF during the flight, changing back to CTAF as the primary channel only during the preparation for the "joining call". Note that the view screen of the camera is shut during flight, so all I'm doing is re-aiming the camera mount by reference to the direction of the camera body. Filming is started before take-off and stopped after landing.

 

You will observe that in the first pass of the "lead aircraft" across the sun, I drop off-station momentarily. It is very difficult to maintain station when looking directly into the sun. Again when approaching the circuit to land, my station keeping varies a little during change of frequencies and making calls. At that time there was another aircraft crossing above our path as well as one in the circuit ahead of us, so the task loading becomes pretty high in those circumstances. Formation was held right through to a good formation landing. You will note just after the "lead aircraft" touches down, the picture takes on a slant to the right due to the very significant turning force of its wake turbulence on my wing. Sharing a 15m wide sealed section of runway for formation take-off and landing requires a great deal of care, planning and precision of execution including accounting for wind direction and the effect that will have on wake turbulence. (I should point out that training for the formation take-offs and landings was done at Corowa where there is a 45m runway width.)

 

 

The flight was more extensive than shown in this edited video, being actually 0.8 hours in duration, during which I had the camera recording HD (1080p) video.

 

 

[Suitman]

Good stuff, David.

 

How did you mount the camera to minimise vibration?

 

Peter

 

 

[Trevor]

Very impresive David. Loved it ! Trevor.

 

 

[Guest davidh10]

Good stuff, David.How did you mount the camera to minimise vibration?

 

Peter

The best way to describe it is to show photographs. I had two photos of the mount as used for stills, and tonight have added a further two pictures to show the way it is now modified (photo-1 and photo-2).

There's a definite trade-off between floating too much and bouncing too much.

 

In addition to what the mount does, the "Powered Stability" mode of the camera is pretty amazing. You will be able to see that in action when I finish editing a video of formation around clouds, as we flew through a little light hail and you can see it splat on the lens filter. Thereafter you can see the relative movement of the lens filter against the scene, until we descended below the freezing level and it melted.

 

Very impresive David. Loved it ! Trevor.

Thanks Trevor. Hopefully it will get better as I gain in experience. Both with taking digital video and with flying formation.

 

 

[Suitman]

Thanks for the photos David. The use of the foam as a dampener within the "springs" certainly was an inspiration. I'm going to have to play around and see if I can fashion something similar for both my GoPro cams and my digital HD video camera.

 

Peter

 

 

[Guest davidh10]

Thanks for the photos David. The use of the foam as a dampener within the "springs" certainly was an inspiration. I'm going to have to play around and see if I can fashion something similar for both my GoPro cams and my digital HD video camera.Peter

The GoPro could be a bit of a challenge as one of the factors that removes the vibration is the inertia of the combined mass of the tripod head and the DV camera. Effectively, in suspension terms, the camera and tripod head become the unsprung weight.

With the mounting location on the trike, my thoughts were that since the control bar is free to move in the horizontal plane, for control of the aircraft, there won't be any transmitted vibration in this plane. All the vibration will be in the vertical plane as the control bar is rigidly attached to the wing and in turn, via the hang bolt, attached to the aircraft frame. This situation may not be the same for other aircraft types.

 

You will notice that I'm still getting some vibration, which depends on engine revs, so this likely isn't the final mount design. The tricky bit is that the springs must not allow the camera to rotate enough to affect the picture and that seems to be less than a few millimetres of travel. Although the camera stability features are very good for eliminating movement in both the horizontal and vertical planes, they do not handle rotation about the sight line. Also, while they do handle "movement", they don't handle "vibration". I haven't published any video from the initial tests before the spring modification, as it was quite unwatchable. The vibration seemed to interact with the camera stability controls to cause the landscape to wave like a flying carpet. Without the stability features enabled, the picture suffered blurring die to picture instability.

 

There's quite a few elements that will go into a successful final design, but for now the current iteration will be usable until I firstly figure out a new design, and secondly have the time to build it.