For KAP I fly a 2 axis radio controlled rig with a live video relay. One of the reasons for this (apart from the obvious ‘what you see is what you get’ view finding) is for the capture of trains. With luck I can frame and track the moving target from on high and hopefuly get the railway in its landscape with the all important traffic.
I spend a lot of time hanging around, kite in the air with the camera bouncing about on the line. I frame my shot and wait for the cues to passing traffic; a signal at green , the warning siren at a level crossing or the distant roar of the approaching diesel. And all the while I need to keep the video link live so that as the train appears in the view finder I’m able to pan and shoot:
Clearly I need to practice a bit with the new kit. This is a pretty quick stretch of track too which doesn’t help! Waiting and tracking trains requires the system to be powered up for extended periods, if the wind and light hold this could be hours. I have tested the system on the ground and I have 5 hours running time based on 2x 11.1v 1450mAh Lipos (one in the sky and one powering the video receiver on the ground) . My monitor screen is the weak link : its battery holds up for just 2 .5 hours- so I carry 2.
With Bft 4/5 buffeting the kite there is nothing I can do but shoot and hope: sometimes the rig movement is beyond saving by gyro and image stabilisation:
Having got the re-wiring done to get the power distribution split between RC and video I needed to test the theory. Today was a bit on the blowy side, I was in the sky between 10 and 12- I had the kite well anchored at 11.58 when the wind got a bit much for the Didak Explorer:
I put a drogue on the tail of the explorer and this definitely helps steady it during gust, even to the point of reducing its characteristic heeling at 20mph by about half of its un-drogued state. It would have been nice to have stronger light but for this exercise all I wanted was proof the system worked. I had video instability problems on the first test of the system which have been resolved by changing the power distribution on the rig.
The shot I imagine I will get is of the parallel routes to the sea passing the grain silos, the wind was in the wrong quarter to work today and by the time I was airborne the light had gone but the object was to test and that went well.
The mistake I’d made was to power everything off the 5v outlet from the video transmitter. On the face of it this looked like a good idea but in practice the power draw of the servos upset the the video.
I separated out the 2 systems with a Y cable from the battery and added a UBEC to take the 11.1v down to 5 for the servos: it worked!
I took off the ferrite ring to save what weight I can. So from a single battery I have 5 and 11v supply without interference between the 2. What weight I have saved by moving to 2.4Ghz control has been lost by using the 5.8GHz video system heigh ho. My rig is a crows nest of wires now as I have worked through the glitches without tidying the cable runs. I’ll save that for a rainy day!