Cut motors to drop altitude fast

[schpenxel]

Ok so I found this on YouTube. They used a P4P and had success with this question. Check it out.

I'm not surprised. I bet the Mavic does it just the same

To say the Mavic has no idea how to right itself is just plain silly. Have you seen how many sensors this thing has inside of it? It knows if it's upside down or sideways or whatever. There are some other videos of people running it into trees.. it falls pretty much sideways almost to the ground and still manages to level out and get back in the air. Same when a bookbag was thrown at it.

 

[Robbyg]

I love the OP's question. I thought about it myself after watching a video of a guy just making it back. The real world problem was mentioned on Page 2 of this thread. At what point do you decide to try a risky maneuver like this?
If your like most people it would be with 15% or less of battery power and a very high altitude. If you did it at that point the motors would not restart because the Mavic wont allow a restart with the batteries that low. So in the real world this probably will not be a viable option but it would be cool to see someone try it with a good amount of charge left on the battery.

Rob

 

[Rich Sugden M.D.]

There are several companies making RC model parachute systems ... get one!

Amazon.com: Hubsan H109S-27 Parachute Recovery System X4 Pro: Toys & Games

Amazon.com : 30" Parachute for Drone, UAV, or RC Airplane : Everything Else

 

[HowSR]

There are several companies making RC model parachute systems ... get one!

Amazon.com: Hubsan H109S-27 Parachute Recovery System X4 Pro: Toys & Games

Amazon.com : 30" Parachute for Drone, UAV, or RC Airplane : Everything Else

Well,
The hubsan chute only works with the human which will trigger it once it's upside down or tilted at a certain angle.

Your second link is just a parachute.still need a way to trigger an launch it.

 

[HeavensAbove]

If the Mavic reaches terminal velocity and tumbles as it falls the arms could end up being retracted by the pressure of air against them. So even if you can restart the motors it wouldn't help your Mavic survive almost certain death as it impacts the ground.

 

[armoredsaint]

Post a video please

 

[rydfree]

It's physics. To tighten itself it would have to have a design with a centre of gravity that would tighten it.

Think of a ship in the water. It requires a buoyancy to bring it upright so weight at the bottom and flotation at the top. Keeps the wet side down.

The Mavic has zero inherent or built in stability and relies totally on the rotors keeping it upright when starting upright.


I welcome comments to my theory....

This has nothing to do with physics , It self levels itself . That's why they are so easy to fly even in Atti mode . It would definitely right itself if it could restart the motors . Not sure if the sensors will let it restart if falling is the only thing I'm not sure of . I've stopped and restarted several craft in flight but none of my camera ships. Even thrown a few in the air then started the motors but they were already initialized .

 

[Capra Vecinului]

But now I see that I couldn't overcome the programming if it was programmed to refuse Power up if tilted.

I realized this was the case when I tried to take off from a tilted Car roof and it refused to power up.

That's like a modern car refusing to turn over if it's parked on a HILL or tilted street.

Guys, correct me if I am wrong, but aren't we talking about two different situations? One being a complete drone start (complete booting sequence with IMU initialization, compass initialization, blablabla initialization etc.), and the other being just the engine restart? The CSC just kills/starts the motors, and does not restart/resets the entire drone! So why are putting the equality sign between these two situations?

 

[JDR]

you could probably ask these guys...

 

[Rich Sugden M.D.]

Well,
The hubsan chute only works with the human which will trigger it once it's upside down or tilted at a certain angle.

Your second link is just a parachute.still need a way to trigger an launch it.

So you deploy the chute ANY time you get into trouble where you think you might lose the drone ... kill the motors and deploy the chute. Maybe DJI would consider such a "deploy" mechanism when the drone is in the air and you've shut down the motors ...

 

[CyberNate]

Ok so I found this on YouTube. They used a P4P and had success with this question. Check it out.

I don't think this will work with the Mavic. The Phantom is tall with the propellers a distance from the center of gravity. The propellers give some drag which allows the center of gravity to right craft to keep it somewhat level, albeit spinning. The mavic's propellers are too close to the center of gravity, which will likely result in tumbling. The Mavic won't start because it is not level.

 

[Capra Vecinului]

The Mavic won't start because it is not level.

Here's this theory again The Mavic doesn't have to start, since it is already started. CSC stops only the motors. CSC only needs to restart the motors.

 

[CyberNate]

Here's this theory again The Mavic doesn't have to start, since it is already started. CSC stops only the motors. CSC only needs to restart the motors.

Hmmm, that's easy enough to test. I didn't realize there was a difference.

 

[HeavensAbove]

Post a video please

I'm not crashing my Mavic for your masochistic viewing pleasure. Sorry.

 

[Kilrah]

Here's this theory again The Mavic doesn't have to start, since it is already started. CSC stops only the motors. CSC only needs to restart the motors.

Are you SURE of that? You can't know without trying. Many multicopter FCs assume no movement when arming/starting motors and take the opportunity to do a quick gyro bias cal, which would screw up everything if tumbling down.

Some DJI birds are known to refuse to start the motors when moving e.g. on a rocking boat.

Shape indeed has nothing to do with it though, it's always going to be way overpowered by the motors anyway.

 

[Capra Vecinului]

No; I am not sure of that; I did not test it. But many of the feedback users gave here were related to their own experience related to POWERING UP their drone on a non-leveled surface, rather than STARTING their motors (on an already POWERED UP drone) via CSC command on that very same non-leveled surface.

 

[CCDD]

Did someone say CSC?

 

[PropPilot]

This has nothing to do with physics , It self levels itself . That's why they are so easy to fly even in Atti mode . It would definitely right itself if it could restart the motors .

Disagree. The Mavic will tumble. Nothing to do with ATTI mode either. That would imply that the aircraft was inherently stable and it is not. For it to upright, there has to be a weight/balance below the prop line to pull the bottom down. Until someone tries it (and eventually someone will) we wont really know.

 

[armoredsaint]

Still waiting for OP's video

 

[RallySoob]

Op's video? ur confused again wow

I cut the throttle to kill altitude on my syma x8 everytime i fly it. But for those who have no skill cuz they only fly gps drones it hard to understand a simple concept such as this.

Learn to fly before u post its a new pre req