P3A - Unusual flight, vertical bouncing?

[pelfed]

So, I was flying a litchi mission today and have a problem.
Part of my mission was flying low at 5m in a straight line for about 100m.
Compass calibrated, wind 15mph plenty of sats.
However, during this straight run, the craft didnt hold at 5m. It seemed to bounce along the path fluctuating.
Almost hit the ground a couple of times. VPS was switched on but never had this issue before. Any ideas?


Sent from my iPhone using PhantomPilots

 

[MapMaker53]

Possibly some vegetation induced wind turbulence at that low altitude with a cross wind that might have occasionally gusted a bit higher? What was the landscape like? Having a P2V+ I have no experience with VPS, but maybe it has a hard time keeping up with data being received when flying above a certain rate of straight line speed? Just some thoughts.

 

[pelfed]

Thanks for the reply - I was flying across an open field... turbulance sounds unlikely.... I've flown across here many times without an issue.... I will try again and see if it happens

 

[Richard R]

If the bouncing was only at the low altitude, I would suspect a VPS issue. You might check that nothing has gotten onto the sensors that might be interfering with the signal. If it happens again in the same area, try reflying the path with VPS off. And both in a mission and manual control. It would be instructive to know if litchi uses VPS inputs for altitude control or just the barometer. You mentioned that you had flown in the area before with no problems, was that low and in what mode?

 

[Mako79]

Turn off VPS. I think the VPS is 10ft max = 3mt approx.
5m is greater than 10ft right??
I think it may be switching the VPS on and off and confusing itself. If you have VPS off and pitching fwd at a fast rate, you will lose altitude. I think whats happening is your bird is turning on VPS when drops below 3 mtrs and bouncing the phantom up until it turns off the VPS. The bird is repeating process every time you are pitching fwd at a fast rate, and hence you are getting bounces.

I don't fly indoors so my VPS is always off.