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Feb 26, 2020, 09:47 PM
If it flies, I can crash it.
rocketsled666's Avatar
Quote:
Either way, I have been in contact with the vendor at Newbeedrone and they firmly believe the capacitor will dampen any voltage spikes that do travel through the entire system. I don’t know as I am not an electrical engineer.
I am, and while a Capacitor will indeed "dampen" voltage spikes ("attenuate" is a better word), attributing the landing behavior to voltage spikes a capacitor might fix is, IMO, B.S.. If the power was noisy enough to matter on landing, you'd experience spasmodic behavior in flight, too. The power system is under a much higher load in flight. If the FC is sensitive to noise in the electrical system on landing, it's only going to get worse as the load goes up in flight, because the noise generally does too.

How the quad behaves when it touches the ground is a function of a lot of variables. Things like how the FC is mounted, what part of the quad is touching the ground first, how hard it touches, how the structure resonantes in response to the impulse, available motor power, some others I'm probably not thinking of, how the PID loops are tuned, and other settings in the FC like Airmode. What it's not a function of is whether or not you have a capacitor across the battery.

What you describe sounds exactly like Airmode to me. Are you certain you actually turned it off when you tried turning it off?
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Feb 26, 2020, 11:08 PM
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Leftyatm's Avatar
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Quote:
Originally Posted by rocketsled666
I am, and while a Capacitor will indeed "dampen" voltage spikes ("attenuate" is a better word), attributing the landing behavior to voltage spikes a capacitor might fix is, IMO, B.S.. If the power was noisy enough to matter on landing, you'd experience spasmodic behavior in flight, too. The power system is under a much higher load in flight. If the FC is sensitive to noise in the electrical system on landing, it's only going to get worse as the load goes up in flight, because the noise generally does too.

How the quad behaves when it touches the ground is a function of a lot of variables. Things like how the FC is mounted, what part of the quad is touching the ground first, how hard it touches, how the structure resonantes in response to the impulse, available motor power, some others I'm probably not thinking of, how the PID loops are tuned, and other settings in the FC like Airmode. What it's not a function of is whether or not you have a capacitor across the battery.

What you describe sounds exactly like Airmode to me. Are you certain you actually turned it off when you tried turning it off?

Yes. I have tried it on, off, on and off in angle and on and off in acro. I have had it permanently off in betaflight. I have had it permanently on in betaflight. I have had it on it’s own switch. Currently I am running it how I saw a lot recommend: disarm, arm, arm+airmode on the same switch in their respective positions; 1,2,3.

I can definitely hear the difference in the motor speed when airmode is enabled.

I too believe it sounds like typical behavior from airmode. But what I don’t understand is it behaved the same with airmode off. I have had it set up identical with hardware and software of another quad and it does not behave this way. I mean perhaps there is a chance airmode is still staying on, but with the amount of research and fiddling in betaflight ad the distinct sound differences when airmode switch is toggled, leads me to be pretty certain is off. Perhaps the fc is just wonky and bad?
Feb 27, 2020, 12:25 AM
If it flies, I can crash it.
rocketsled666's Avatar
If you have the identical HW on another quad, swap the FCs and see what happens. It follows the FC or it stays with the frame, either way you have your answer.

Stays with the FC, replace the FC. Stays with the frame, you need to look at how the FC is mounted.

First make sure everything is nice and tight and the stack can't move around. If it passes that inspection, you need to look at mounting the FC differently, with soft mounts if you're not already using them, for example.

I did have a quad once that misbehaved a bit like you describe. Battery on the bottom, where the heads of the screws that held the FC in place were also located. The battery could press on the screw heads and the stack wasn't screwed down tight. In flight everything was fine, the battery kept enough pressure on things to keep the stack from moving around. But when I landed, if I hit the battery just right it'd move the FC and the quad would do something exciting. I reached this conclusion after observing the behavior and finding loose screws, and then seeing the problem go away once the screws were nice and tight.
Last edited by rocketsled666; Feb 27, 2020 at 12:33 AM.
Feb 27, 2020, 08:58 AM
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Ace12GA's Avatar
Quote:
Originally Posted by Leftyatm
....
At ace12g yea I tried disarming immediately upon touching the ground. If I do, it literally will not hop but violently flip and dart toward the ground with full motor input on some of the motors. My other quads, I always disarm when I hit the ground and no issues arise. Maybe a slight bounce, but that’s airmode.
The motors continue to spin and do stuff after you've disarmed? That is wrong, like really wrong. If you haven't done so, time to flash Betaflight clean, and setup everything again. Disarm should kill the quad instantly. No more motors. No control, just dead in the air. There is something wrong with your FC. Reflash, with a full erase, and set it up again. See if that sorts it. If it doesn't, I'd replace the flight controller. Take notes on your Rx configuration, serial ports configuration, board orientation, etc.. pretty much screen grab the settings page. That's usually the thing that messes people up when setting up from scratch. Confirm you are flashing the correct firmware for your FC as well.

Quote:
Originally Posted by Leftyatm
....
I have my flight controller loosely mounted so that it can wiggle a bit on the standoffs and grommets. I though everyone was soft mounting their flight controllers? Maybe mine is too loose. I can try tightening it a bit but then there is no play. I thought you wanted a bit of give. Maybe not?...
What? Like, wiggle when you move the quad, or wiggle when you hold the quad and try to move the FC? I hard mount mine on nylon standoffs. Never had an issue. I have one that came with rubber grommets, which I mounted as firmly as possible, same deal, no issues. Definitely never mount them loosely.
Feb 27, 2020, 11:43 AM
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Leftyatm's Avatar
Thread OP
Quote:
Originally Posted by Ace12GA
The motors continue to spin and do stuff after you've disarmed? That is wrong, like really wrong. If you haven't done so, time to flash Betaflight clean, and setup everything again. Disarm should kill the quad instantly. No more motors. No control, just dead in the air. There is something wrong with your FC. Reflash, with a full erase, and set it up again. See if that sorts it. If it doesn't, I'd replace the flight controller. Take notes on your Rx configuration, serial ports configuration, board orientation, etc.. pretty much screen grab the settings page. That's usually the thing that messes people up when setting up from scratch. Confirm you are flashing the correct firmware for your FC as well.



What? Like, wiggle when you move the quad, or wiggle when you hold the quad and try to move the FC? I hard mount mine on nylon standoffs. Never had an issue. I have one that came with rubber grommets, which I mounted as firmly as possible, same deal, no issues. Definitely never mount them loosely.

When disarm, motors stop immediately. But on the landing issue, they will spike up real fast.

If I disarm in air, motors stop immediately and it drops. If I am landing and disarm and it lightly touches the ground, the motors surge and full bore power and it flips. Then it shuts off motors. It is demented!

As far as soft mounting. I am using rubber dampers that came with included kit. It doesn’t wiggle if I move quad. If I apply pressure to the flight controller, I can see it have some wiggle room. I wouldn’t go as far to say it’s loose. But I also wouldn’t say it is tightly mounted amidst the rubber dampers. More “snug” than anything.

I may try torquing then down a bit.

I was looking at the holy to kakute stack. If this thing keeps up, I may just swap out the entire stack for that set up. I love the frame and how it flies and looks. But the unpredictability of this quad with this stack set up is a bit unnerving.
Feb 27, 2020, 03:23 PM
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Ace12GA's Avatar
Quote:
Originally Posted by Leftyatm
When disarm, motors stop immediately. But on the landing issue, they will spike up real fast.

If I disarm in air, motors stop immediately and it drops. If I am landing and disarm and it lightly touches the ground, the motors surge and full bore power and it flips. Then it shuts off motors. It is demented!

As far as soft mounting. I am using rubber dampers that came with included kit. It doesn’t wiggle if I move quad. If I apply pressure to the flight controller, I can see it have some wiggle room. I wouldn’t go as far to say it’s loose. But I also wouldn’t say it is tightly mounted amidst the rubber dampers. More “snug” than anything.

I may try torquing then down a bit.

I was looking at the holy to kakute stack. If this thing keeps up, I may just swap out the entire stack for that set up. I love the frame and how it flies and looks. But the unpredictability of this quad with this stack set up is a bit unnerving.
Have you tried a clean flash on the firmware? Might be worth trying before you replace it.
Feb 27, 2020, 04:19 PM
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Leftyatm's Avatar
Thread OP
Quote:
Originally Posted by Ace12GA
Have you tried a clean flash on the firmware? Might be worth trying before you replace it.
I have not.

Frankly, I’ll be honest. I don’t know how to. I’ve watched videos, but I would be afraid to mess something up more. I wish I paid more attention in my college computer course, I just did bare minimum to get by. Doh!


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