A motor cut out theory

[Vassilag]

Having experienced a similar situation recently - thankfully not a crash - I suspect that some sudden motor cut outs may be caused by insects!

Flying in 100m high it is impossible to see a large mosquito or a huge fly but it may be there. In addition, keep in mind that everything above the drone is getting sucked by the blades, when the software understands that a motor looses spins then the motor is out. This is a safety feature which is very useful when the drone flies around people or indoor but it is catastrophic when it is 100m high above the sea!

Possibly, in these cases - high altitude - Parrot should not cut out the motor! - The motor should stay active struggling as much as possible while the other motors adjust for a controlled emergency landing.

What do you believe?

 

[Rocky the FS]

It would take a much more substantial insect than mosquitoes or bees. Look at this thread:

Anafi is the queen bee ?

Seems the humm of bees is identical in pitch to the Anafi. Has this been an issue?

parrotpilots.com

 

[Landbo]

Having experienced a similar situation recently - thankfully not a crash - I suspect that some sudden motor cut outs may be caused by insects!

Flying in 100m high it is impossible to see a large mosquito or a huge fly but it may be there. In addition, keep in mind that everything above the drone is getting sucked by the blades, when the software understands that a motor looses spins then the motor is out. This is a safety feature which is very useful when the drone flies around people or indoor but it is catastrophic when it is 100m high above the sea!

Possibly, in these cases - high altitude - Parrot should not cut out the motor! - The motor should stay active struggling as much as possible while the other motors adjust for a controlled emergency landing.

What do you believe?

I know it's a "very loose" theory you have conceived. Even if you fly on tall grass and mow them with a prop, you will not find an engine stopping. It takes a lot before it happens. Therefore, your theory of mosquitoes does not fit either.

I don't think you have thought about the impact of your proposal as when an engine stops, your Anafi falls to the ground like a rock and is most likely damaged.

Regards Leif.

 

[Vegasrobbi]

I struck a large flying bug with my Anafi, I was low to the ground and the impact was enough to deflect Anafi into a bush.

O


Here's my Anafi playing dead bug in the snow. I'm going to miss Anafi #1 with all it went through it was actually the controller that failed and Parrot gave me Anafi #2

 

[Jagerbomb52]

Love the dead bug in the snow.

 

[MavicPro1966]

I don’t like the motors cutting off. If you fly into a swarm of insects it just might bring it down.

 

[Rocky the FS]

......Even if you fly on tall grass and mow them with a prop, you will not find an engine stopping.....

Perhaps not tall grass, but while back my Anafi bounced up from the landing pad in wind and hit a weed roughly two mm in diameter at the edge. The motors stopped and it began beeping. Although there was no leading edge damage, the props obviously hit the trailing edge on the other hub and caused a small nick. I had just replaced that set of props that day!!

 

[Landbo]

Perhaps not tall grass, but while back my Anafi bounced up from the landing pad in wind and hit a weed roughly two mm in diameter at the edge. The motors stopped and it began beeping. Although there was no leading edge damage, the props obviously hit the trailing edge on the other hub and caused a small nick. I had just replaced that set of props that day!!

A 2 mm blade of grass cuts a prop over without problems and you can't se it on the props leaves or the engine stops. If you fly Anafi into the leaves on a tree, normally nothing happens if you do not hit a thick branch. An BLDC engine must be almost physically blocked to make it stop. The reason why an engine's ESC stops supplying Power is because the engine will pull out all the Amp that the battery can deliver when it is blocked. You must remember that the motor control unit (ESC) supplies a three-phase DC current / voltage to the motor with a variable frequency (motor rpm.) and pulse width so that the pulse does not get wider than the motor can just keep its revolutions and thus save battery power. Opposite vil a brush DC motor use much power into it is heat loss, especially when it has to work hard at low RPM.

The type of engine that sits on an Anafi is the most efficient engine available at the same time. It has a very high torque at both low, mid and high revs. It is also the reason why they are used in high end battery drills and as a driving force for electric bicycles etc.

A short easy read theory: Brushless DC electric motor - Wikipedia

Regards Leif.

 

[Rocky the FS]

A 2 mm blade of grass cuts a prop over without problems and you can't see it on the props leaves or the engine stops. ..
Regards Leif.

Not a blade of grass but a tough weed stalk....much different animal. We have weeds out here that grow 6 feet tall with an inch and a half diameter stalk....not even a weed trimmer will cut those....you need a metal blade.....or an axe!

 

[Landbo]

Not a blade of grass but a tough weed stalk....much different animal. We have weeds out here that grow 6 feet tall with an inch and a half diameter stalk....not even a weed trimmer will cut those....you need a metal blade.....or an axe!

Oh, don't overdo it. You have, yourself mentioned 2 mm and this is of course the thickness I refer to when I answer you. And even a 2 mm dry blade of grass will be cut by a prop without it being visible on the rotor blade or the engine stopping.

Regards Leif.

 

[Rocky the FS]

Come visit. Not all parts of Idaho are the same. I'd be happy to show you 6 foot tall weeds!
What do you think the result would be if the props tried to cut 2 mm nylon fishing line?

 

[Landbo]

Come visit. Not all parts of Idaho are the same. I'd be happy to show you 6 foot tall weeds!
What do you think the result would be if the props tried to cut 2 mm nylon fishing line?

Guess you can see it on the prop blades but the motor does not stop. You can check for yourself.

It was a thick fishing line, what do you use it to catch ? Big sharks ?

Regards Leif.

 

[Rocky the FS]

Salmon.