I'm thinking of flying over a 400ft cliff. What can I expect. The coordinates are 40.045357, -120.885655 . How will the H react? Has anyone done this?
Flying off a cliff
- Thread starter Mindbank
- Start date
PatR
Premium Pilot
The H won't care as long as you maintain line of sight between the aircraft and the transmitter. If the video feed starts to get shaky, bring it back up. The first indication of loss of signal occurs wit the video feed so if the command and control signal is getting blocked by the airframe the video will fade first as a warning.
What is displayed in the altitude data on the ST-16 is meaningless to the H. It's just another number where flight control above or below a line is concerned.
What is displayed in the altitude data on the ST-16 is meaningless to the H. It's just another number where flight control above or below a line is concerned.
PatR
Premium Pilot
What’s the tallest obstacle between the take off point and the cliff? Set it for 100’ higher. The H should rise straight up to RTH height if activated but setting a high RTH allows for more rise over a given distance if it starts to come back before reaching full RTH height. I say if because I’ve only seen it rise straight up to RTH height before initiating lateral movement.
FlushVision
Premium Pilot
Living in a very hilly area I've very often flown at negative heights since I tend to take off from the higher points. Take note of what PatR says about signal loss: As with most UAS' the H480's antenna are positioned on the underside of the air frame so give optimum performance when the aircraft is at a height higher than the pilot's position. Flying at a negative altitude to your position, then, will not be optimal and so will tend not to have such a robust connection...don't fly it too far away from you and you should be all right. Glitches in your video should act as a warning that you are pushing it too far away and risk control loss.
RTH height that you have set will be adhered to by the aircraft. If you've set it at 100', say, then it will rise to that 100' ABOVE THE TAKE OFF LEVEL, so if you lose control at minus 100' then it will rise up 200' to plus 100' if RTH is initialted. (give or take a few feet because of barometric inaccuracy)
PatR
Premium Pilot
Something to consider as well is battery level. If you are 200' below your launch height you'll need to make sure you have enough remaining battery to make the climb back up plus the distance back. RTH is another consideration if the low battery warnings are achieved. Initiating a 200' or more climb after a low battery warning occurs may be more than the battery can deliver and still traverse the distance back to the landing site. Bear in mind that a straight up climb requires more power and drains a battery faster than maneuvering flight at a constant altitude. If it goes into auto land mode before making it back to the edge of a cliff the aircraft could be in for a mighty long descent before it gets to the ground. You could run out of battery before it lands and end up with it falling instead of landing. Lot's of things to consider and work with that differ from "normal" flights that start out low, go high, then return to low. Gravity will not work to your benefit when flying below the launch site altitude.
FlushVision
Premium Pilot
What PatR says is good. But don't let all this put you off...just keep all this info in mind when you are doing your flight. For example, if you are a pilot that looks to land at 14.4v, then when doing a negative altitude flight think 14.6v or better. Keep it a bit closer to you. Start with the low stuff early in the flight and return it to 'normal' altitude as soon as you've got what you want (don't hang around for that extra minute of video footage, you can get that on your next battery).
I've done lots of negative altitude flights. Best to use more batteries than look to get that bit extra out of an individual battery. I think there is another thread current about negative altitude flights. Take a look at that and the issue of perspective: It is harder to judge distances from above...you may be closer to the ground than you realize so think about taking a spotter with you.
More importantly, if you doubt your ability to conduct a negative altitude flight then don't rush it: have a practice from a small hill over land that you have assessed by walking it.
I've done lots of negative altitude flights. Best to use more batteries than look to get that bit extra out of an individual battery. I think there is another thread current about negative altitude flights. Take a look at that and the issue of perspective: It is harder to judge distances from above...you may be closer to the ground than you realize so think about taking a spotter with you.
More importantly, if you doubt your ability to conduct a negative altitude flight then don't rush it: have a practice from a small hill over land that you have assessed by walking it.
PatR
Premium Pilot
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