I done a bit crazy experiment on Solo

User Name · Apr 1, 2016

Just my marginally scientific thought on the issue - it could be that near the ground, the air flow from all the props is being deflected out to the sides and causing a small area of low pressure in the middle, which is where the flight controller (and barometer) is located. You try to surround the barometer chip with foam to reduce wind/air currents, but it will still read larger general changes in pressure, which you want, and which this could be.

What's interesting is the inconsistency of the times when it'll bounce and flip on landing. I've auto-landed probably a majority of the times I've flown mine, and the landings have always been soft and solid with barely a bounce, if any at all.

I agree with the above - that flipping over is the result of a lateral move where the legs get caught on something, BUT a hard landing could be enough of an input to the accelerometers to be read as a change in position which the flight controller would then try to react to, which then leads to a lateral move, the legs getting caught and a flip.

Pedals2Paddles · Apr 1, 2016

User Name said:
Just my marginally scientific thought on the issue - it could be that near the ground, the air flow from all the props is being deflected out to the sides and causing a small area of low pressure in the middle, which is where the flight controller (and barometer) is located. You try to surround the barometer chip with foam to reduce wind/air currents, but it will still read larger general changes in pressure, which you want, and which this could be.

Other way around. It's causing an increase in pressure under the solo, which is being picked up by the barometer as a descent. Air pressure increases as altitude decreases. So an increase in pressure from the prop wash at the ground will be interpreted by the barometer as a reduction in altitude.

That does not however mean the solo will immediately react by increasing thrust. It has a little more brains than that. Hence why it doesn't just keep bouncing up and down in the air as it tries to land.

User Name · Apr 1, 2016

Pedals2Paddles said:
Other way around. It's causing an increase in pressure under the solo, which is being picked up by the barometer as a descent. Air pressure increases as altitude decreases. So an increase in pressure from the prop wash at the ground will be interpreted by the barometer as a reduction in altitude.

Ahhh, that's right. Serves me right for trying to analyze something on 4 hours of sleep!

cameraguy · Apr 1, 2016

You would have nailed it on 5 hours, I'm sure of it!

SPP · Apr 1, 2016

I done a bit crazy experiment on Solo

P2P, ( is my post showing I quoted your answer ? ...I cant find quote button ...LOL )
Agree, Solo would have filters such parameters.
Wind influence can be prevented, but GPS drift is hard to predict in real time.
The flight graph I pasted earlier, it took almost 9 minutes for Solo to get proper GPS lock and drifted total of 3 meters. 8 to 10 sats during GPS lock.
There are apartment to north east side, not 100% clear sky at LZ.
Okey Dokey ...many thanks for the info.

Seaair7 · Apr 2, 2016

Did u try grabbing the props at full speed to stop it? your lucky that your not wearing a few props your asking for it .

AKPhantom · Apr 2, 2016

Edit: @SPP Said!
Next time I will wear motorbike helmet and thick jacket and do this test again, but I will weight solo down with weight of say 4-6kg. Still too risky my hands being on top of battery bay all the time.
.[/QUOTE]
Ahh yeah, then ah lick your other finger and ah jam-it in a light socket...wait for it....wwwait forrr it!

Pedals2Paddles · Apr 2, 2016

I can't believe he's still saying "next time".

SPP · Apr 3, 2016

Ha ha ha, it seem I quoted wrong. I don't know how to use the quote feature.

This is what I wanted to quote from P2P answer :
Flipping over on landing or takeoff has nothing to do with altitude. If it just thought it needed to reduce it's rate of descent, it would apply an even increase in thrust. Furthermore, Arducopter has extensive filtering and intelligence to determine what's going on with it's position. It's not just the barometer. It also has the accelerometers, which would clearly indicate no increase in descent rate. It's not that dumb. And even if it was, there's nothing you can do about it. Unless you plan to bring a huge steel mesh with you everywhere and redesign the legs to work with it.

Flipping over is a result of an attempted lateral move, which is unrelated to it's perceived altitude. If it tries to move left/right/forward/back while legs are on the ground, it's going to tip over. That move could be poor hand piloting, wind pushing it, or GPS drifting.

If your children can't handle the most critical phases of flight (landing and taking off), then they shouldn't be handling the controls.

, dont get too excited boys....
.