Zero altitude

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Can I;
1; Stand on bank above River or lake, launch P3a,
2; fly it down to waterside and land on shoreline
3; recalibrate it then to Zero altitude

so I could then fly say 3' above surface of water,?
Screen Shot 2019-12-21 at 19.33.39.png
 

Fly Dawg

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3; recalibrate it then to Zero altitude
To reset your altitude to zero you would need to shut down and re-start the aircraft. That's the issue.
 
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Hmm, thats how I read it too.
Not actually done this flight yet so I suppose the next best thing it
take off>land at at waterside & note -altitude> fly over water at +3'
(and don't forget it) :)

thanks
 
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To reset your altitude to zero you would need to shut down and re-start the aircraft. That's the issue.
Apart from losing your real home point, why wouldn’t that work if you had connectivity?
 

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Can I;
1; Stand on bank above River or lake, launch P3a,
2; fly it down to waterside and land on shoreline
3; recalibrate it then to Zero altitude

so I could then fly say 3' above surface of water,? View attachment 116362
You can fly 3 feet above the water without all that messing around.
Just fly down to three feet above the water and do whatever you want.
But be careful.
Flying three feet away from any obstacle is risky and the ground or water is a big obstacle.
Also your drone will appear further from the water in the live view due to the wideangle lens.

There's no advantage to landing and resetting your altitude close to the water.
When only a few feet is the difference between going home with your drone of losing it, the displayed altitude in the app cannot be relied on.
It very commonly drifts a few feet during the time of a flight.
 

Fly Dawg

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Apart from losing your real home point, why wouldn’t that work if you had connectivity?
It will reset the altitude based on BP. If you do not shut down the aircraft, the ALT would be negative, which would mean calculating negatively for the flight profile you want. If you shut down the aircraft, it will set the current position as zero altitude. There is not a "reset" method for that otherwise. The home point would be updated to that location, not the original launch point. Not anothet way to accomplish what the OP asked IMO.
 
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It will reset the altitude based on BP. If you do not shut down the aircraft, the ALT would be negative, which would mean calculating negatively for the flight profile you want. If you shut down the aircraft, it will set the current position as zero altitude. There is not a "reset" method for that otherwise. The home point would be updated to that location, not the original launch point. Not anothet way to accomplish what the OP asked IMO.
Ok. So if I read this right then you are confirming that the only disadvantage to powering down and back up on the shoreline is losing the original home point?

I’m just curious to understand from an academic standpoint and “how these things work.” I understand from @Meta4 post that there isn’t a real reason to do it. But I’m just testing my understanding.
 

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So if I read this right then you are confirming that the only disadvantage to powering down and back up on the shoreline is losing the original home point?
No...it is the barometer reset. My point being, that if you land away from your original home point ( In a negative value ), it will reset the home point with a power down and up reset. Additionally, it will reset the barometer to Zero at that point. That way it changes the reference altitude.
 
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No...it is the barometer reset. My point being, that if you land away from your original home point ( In a negative value ), it will reset the home point with a power down and up reset. Additionally, it will reset the barometer to Zero at that point. That way it changes the reference altitude.
Yes. That’s how I understood. I just think I wasn’t making myself clear. But I understand now.
 
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The important point that to have in mind is what Meta4 says - if you fly 3' above the surface there is no guarantee that this will be precisely 3' through all the flight. It can vary a bit and flying so close to the surface can suddenly become a touch down moment . The craft at that altitude measures the distance from the surface by VPS which is reliable over the ground but not as exact over the water. That's why flying very close to the water surface must be done very carefully with observing the live view all the time. If the altitude over starting point is + or - doesn't matter. Just remember the value and maintain it during the flight and carefully observe the monitor and it should be fine.
 
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Can I;
1; Stand on bank above River or lake, launch P3a,
2; fly it down to waterside and land on shoreline
3; recalibrate it then to Zero altitude

so I could then fly say 3' above surface of water,? View attachment 116362
Only by trying out new ideas do we really learn and develop. So good luck and I hope that the video is special enough to justify the risk. If you were standing on the shore you could resolutely maintain the drone in view and immediately notice any drift towards the water. But this gets progressively more difficult as the drone moves away from you.

Flying from up on the raised bank takes away your ability to monitor the height above the water. I don't think that monitoring the video feed is going to be foolproof. Any glitch in the video feed could spell disaster. I recently flew my drone slowly into the side of a combine harvester. I got away without any damage but it was embarrassing. I am not sure what happened but I was 300 yards away and flying using the video feed so I think that the video froze for a couple of seconds...

I fly a P4 and I have never flown a P3. When filming the wheat harvest I have flown around 3 feet above the ears of wheat but I have found the VPS to be unreliable and the P4 drifts down but I think never up. The altitude drift seems to be worse over the wheat than I have experienced flying very low over the freshly turned earth when filming ploughing. I have assumed that the swaying wheat defeats the VPS.

Flying low over water is notoriously risky and the VPS struggles. I have had a few heart stoppers when flying along the waterline at the beach - and that is when the sea was flat calm and waves merely rolled smoothly in and out.

So my advice is to weigh up whether the potential benefit really justifies the risk and whether you are willing to sacrifice your bird.

All the best, Martin
 
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Just remember to push forward on the left stick if you think you’re too low... because you probably are. Altitude is your friend lol 😎 of course this post assumes you fly the same mode I fly in which the left stick controls your height
 
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No...it is the barometer reset. My point being, that if you land away from your original home point ( In a negative value ), it will reset the home point with a power down and up reset. Additionally, it will reset the barometer to Zero at that point. That way it changes the reference altitude.
Realized that you meant physically power down by the battery button. Not a motor off with the sticks. My bad.
 
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Wise to not trust the screen entirely, ordinarily I wouldn't probably fly like that preferring to stand at waterside and visually guess height, where I have in mind doesn't readily seem to have an access point to waterside but I'll go back and look it over again.
Remote/distance flying is more demanding and quite the opposite what I've agreed and been tested on for our new UK 'licence' though apart from another income stream from hobbyists like myself it serves little or no point I can see
 
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There was a thread here some time ago from a guy who was standing lakeside and doing just that - flying about three feet off the water. He took his eye off of it for a few seconds and the thing descended enough on its own (IIRC) to put itself in the drink. These aren’t precision flying machines like cruise missiles. But we don’t need to guess at it. Just learn from one guy who paid the price. :))
 
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Not to mention $600 just to be able to drop it in the water and have it (hopefully) survive...maybe it's just me, but I'd rather use a better drone and keep around 10 feet off the water.
 

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