Cause of uncontrolled spin on Inspire

scubaddictions · Mar 30, 2023

By now I'm sure many of you have seen the video of an Inspire (2?) spinning nearly out of control over water, it's been making the rounds on social media the last few days.

I was wondering if anyone has a good opinion on what caused this? I've searched this forum in every possible way I can think of, can't find any mention of it. I've searched around outside the forum and mostly found reports of a gimbal screwing up causing the drone to spin, and a few reports of this happening and the pilots being able to arrest the spin by switching into ATTI mode temporarily.

The drone is clearly missing a prop in the 2nd half of the video but appears to have a complete set at the beginning, and only loses one pair on a motor after impacting a boat. It's still airborne, and still spinning, only less rapidly after the impact. No idea if the spin slows due to the loss of a prop or the simple fact that it impacted something, or both.

Thoughts?

Donnie Frank · Mar 31, 2023

Is it just me, or is it missing a prop? Hard to tell from the GIF, but it looks like the left-rear prop is missing. You can see it in the latter part of the video. So I imagine the spin is coded into the firmware to keep the Inspire 2 aloft in the case of propulsion issues.

D

IronSky1 · Mar 31, 2023

I had similiar occurance a couple years ago. I had a hairline crack in prop which broke off once in air. Very hard to control just ran into the trees after less then minute

scubaddictions · Mar 31, 2023

Donnie Frank said:
Is it just me, or is it missing a prop? Hard to tell from the GIF, but it looks like the left-rear prop is missing. You can see it in the latter part of the video. So I imagine the spin is coded into the firmware to keep the Inspire 2 aloft in the case of propulsion issues.

D

See the last paragraph in my original post, the video starts with a full set.

EarlDGrayJr · Mar 31, 2023

Prop fell off. Probably cracked at start. Bad motor can also cause the behavior.

scubaddictions · Mar 31, 2023

EarlDGrayJr said:
Prop fell off. Probably cracked at start. Bad motor can also cause the behavior.

Has a full set (though it's impossible to tell if they're all rotating) while the drone is spinning in the first half of the video. Only loses props on one motor after hitting the boat.

EarlDGrayJr · Mar 31, 2023

Again, this is one rotor not spinning behavior. Whether no prop or bad motor, the result is the same.

Donnie Frank · Mar 31, 2023

scubaddictions said:
See the last paragraph in my original post, the video starts with a full set.

Copy that. Not sure how I missed that. I'm really not a morning person.

With this in mind, it seems a catch net might be a very cost-effective part of one's drone kit. I can't imagine there's a "safe way" to catch a spinning Inspire 2. A net or tarp seems like the best option. This would obviously be, at minimum, a 3-man endeavor.

In the videos I saw of rotating drones, the pilot still had directional control of the drone.

That doesn't seem to be the case with the Inspire 2.

NOTE: The original video I saw was of a 4-prop traditional quadcopter missing 2 of it's 4 motors. I can't seem to find that video anywhere.

D

scubaddictions · Mar 31, 2023

EarlDGrayJr said:
Again, this is one rotor not spinning behavior. Whether no prop or bad motor, the result is the same.

Entirely possible. If true it raises another oddity: one motor stops rotating so the drone spins. It hits the boat, and props on one motor shear off. What's the likelihood that the motor to lose its props is the one that isn't spinning? Seems like a freewheeling prop would just conform to the surface it's impacting rather than shattering. And if that's the case now a quadcopter has one dead motor and one spinning motor without props, and the drone remains airborne.

Jorge Vergara Latoja · Apr 1, 2023

scubaddictions said:
Totalmente posible. Si es cierto, plantea otra rareza: un motor deja de girar y el dron gira. Golpea el bote y los puntales de un motor se cortan. ¿Cuál es la probabilidad de que el motor que pierda sus puntales sea el que no gira? Parece que un accesorio de rueda libre simplemente se ajustaría a la superficie que está impactando en lugar de romperse. Y si ese es el caso, ahora un cuadricóptero tiene un motor muerto y un motor giratorio sin accesorios, y el dron permanece en el aire.

entiendo tu propuesta y puede ser posible siempre y cuando sean motores alternados en ambos brazos, ese que gira en sentido horario y el otro que gira en sentido antihorario este funcionando... en ese caso si se pudiera sostener en el aire , quizás el giro descontrolado se deba a que la IMU trata de compensar el giro de estos motores al no tener un registro de control sobre los otros dos motores (uno sin hélice y el otro parado)... ya que el que no tiene hélice girará sin ningún tipo de esfuerzo, por lo que la IMU no tendrá respuesta a los cambios que haga en el motor y en el caso de motor parado (fallo de la tarjeta de control) menos...

atmosphericarts · Apr 1, 2023

This happened to me a couple years ago. In my case the glue that holds the arms together failed and a motor tilted inwards (which I think I see in the video), causing extreme uncontrolled yaw like this. I installed the atellani arm brace upgrade kit and my confidence in the platform was restored.

Jorge Vergara Latoja · Apr 1, 2023

scubaddictions said:
Entirely possible. If true it raises another oddity: one motor stops rotating so the drone spins. It hits the boat, and props on one motor shear off. What's the likelihood that the motor to lose its props is the one that isn't spinning? Seems like a freewheeling prop would just conform to the surface it's impacting rather than shattering. And if that's the case now a quadcopter has one dead motor and one spinning motor without props, and the drone remains airborne.

atmosphericarts said:

This happened to me a couple years ago. In my case the glue that holds the arms together failed and a motor tilted inwards (which I think I see in the video), causing extreme uncontrolled yaw like this. I installed the atellani arm brace upgrade kit and my confidence in the platform was

Click to expand...

A few years ago I bought that Antellani Kit and I did it thinking of minimizing the vibrations of the engines when using carbon fiber propellers, and now that you comment on this, about the failure of the glue that keeps both ends of each arm aligned, all the more reason to have that engine installed on the Inspire. Thanks for your comment.! Greetings.!

scubaddictions · Apr 1, 2023

atmosphericarts said:
This happened to me a couple years ago. In my case the glue that holds the arms together failed and a motor tilted inwards (which I think I see in the video), causing extreme uncontrolled yaw like this. I installed the atellani arm brace upgrade kit and my confidence in the platform was restored.

I like it! Seems quite possible.