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Stopping the props mid-flight

H3Alpha

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Sep 3, 2018
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There's a difference between having an inquiring mind/pushing the boundaries, and borderline intentional crashing, but hey, whatever floats your boat. I've got better things to do with my money than throw it away.
 
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Spark 317

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Has anyone ever thought there must be a faster way of bringing the drone down and has anyone here been brave enough to stop the props mid-flight by pulling the sticks in and down and then just restarting them closer to the ground.


Chris Rollins of YouTube did it to a Mavic Pro about a year or so ago. Check it out .

 
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polish_pat

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Sep 21, 2018
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I had an older cheaper drone that let you cut the motors off at anytime. At about 200ft if I stopped the motors, they would free spin and the spinning created enough drag and lift to let the thing land fairly soft. Enough so that I've done it numerous times without it breaking. The spark is a lot heavier and smaller, I would never think of trying it if I could, but I wonder if it would the same thing?

That my friend is a brilliant observation few people ever have and is the only thing that is the missing factor in a general false idea of "what happens if a helicopter loses the top rotor"...most people say their prayers, anybody with some knowledge of aerial vehicles know the helicopter becomes a glider. Pilots just adjust the axis of the propeller and can spin up the rotor and slow it down for a safe landing. Every pilot trains for this to get their license.

As for the spark, or any other device, if the propeller are big enough to make it fly, they also are to allow some leverage over a complete engine failure...the issue is those situations require complete human control, and the AI of the spark doesnt respond well to abnormalities and often stands in the way leading to flyaways. So with no way to take control, the spark will rely on JESUS THE LORD ALMIGHTY that has a direct connection and shows up as 1 of X connected satellites
 

rak83

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Mar 30, 2018
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With NLD and the parameters modded I can bring my spark down very very quickly. Its a little scary because it wobbles back and forth pretty hard when you let go of the stick and it hovers again
 

SIDEHACK

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That my friend is a brilliant observation few people ever have and is the only thing that is the missing factor in a general false idea of "what happens if a helicopter loses the top rotor"...most people say their prayers, anybody with some knowledge of aerial vehicles know the helicopter becomes a glider. Pilots just adjust the axis of the propeller and can spin up the rotor and slow it down for a safe landing. Every pilot trains for this to get their license.

As for the spark, or any other device, if the propeller are big enough to make it fly, they also are to allow some leverage over a complete engine failure...the issue is those situations require complete human control, and the AI of the spark doesnt respond well to abnormalities and often stands in the way leading to flyaways. So with no way to take control, the spark will rely on JESUS THE LORD ALMIGHTY that has a direct connection and shows up as 1 of X connected satellites
Don't forget the folding propellers rely on centrifugal force to stay deployed.
 

Chips

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Sep 2, 2017
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even if it did work the spark would most likely start to go end over end or drop like a rock or come down on the back end because of the battery having the most weight . at 400' how long do you think it would be before it hit the ground ?

My Spark's motors stopped at 80 metres (250 feet) while landing and I saw it coming straight down. It didn't go end over end and when it was visible, I noticed the propellers windmilling. As you rightly noted, the battery's weight will pull one end down and I also noticed that so it was not flat as it fell.
 
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polish_pat

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Don't forget the folding propellers rely on centrifugal force to stay deployed.
Not quite. The way you put it, it seems like they RELY on being spun to stay extended, they dont, they just need it to deploy, then they stay deployed because they are not spring loaded. So in flight, i dont see how that could become problematic unless an external factor somehow folded them...
 

SIDEHACK

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Not quite. The way you put it, it seems like they RELY on being spun to stay extended, they dont, they just need it to deploy, then they stay deployed because they are not spring loaded. So in flight, i dont see how that could become problematic unless an external factor somehow folded them...
Hmmm.......The next dry day I'm gonna test that with my leaf blower:) I made the statement because I noticed that my props are not straight when I stop the motors. Interesting........
 

Spark 317

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I noticed that my props are not straight when I stop the motors. Interesting........


The motors stop, center hub of the props stop, but the inertia of the hinged portion of the props is still there and carry the prop till it stops.
 
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polish_pat

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Hmmm.......The next dry day I'm gonna test that with my leaf blower:) I made the statement because I noticed that my props are not straight when I stop the motors. Interesting........
Please do, I did. And that controlled stress test I gave to my spark was the first time I was impressed by how quick and efficiently the spark reacts to gusts...and these are concentrated gusts. I did it from below, side and above, and it moves maybe in a 2 feet radius.
But dont take my word, look at my video taken just a few days ago on a night where for the first time in 6 years we had a multiple tornado warning for a full 12 hours...look at how the trees move for comparaison.
 

SIDEHACK

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I was more curious about the Spark props being able to counter rotate after a power failure. I tried using my wife's hairdryer, admittedly not a lot of volume, and the props weren't able to overcome the magnetic drag of the motor. They just started to fold some and would not spin the motor more than a tiny amount. I'll wait and try the leaf blower.
Another thought is if the Spark would fall in a flat attitude even if the battery stayed mounted. Unless it did I doubt the props would spin.
 

polish_pat

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I was more curious about the Spark props being able to counter rotate after a power failure. I tried using my wife's hairdryer, admittedly not a lot of volume, and the props weren't able to overcome the magnetic drag of the motor. They just started to fold some and would not spin the motor more than a tiny amount. I'll wait and try the leaf blower.
Another thought is if the Spark would fall in a flat attitude even if the battery stayed mounted. Unless it did I doubt the props would spin.
Hairdryer... Allow me to to laugh. :DYou did see the word TORNADO right!!!!! :eek:
Here's another interesting thing I found that gave me more insight about this drone. Send the spark up when you get the P-GPS lock, not in sport but normal, then bring it down to a level you can catch it from under without the bottom sensor correcting it away. Then rock it slowly side to side, front to back, enough so you clearely hear the props spin faster but not so much as to geting them stopped...you'll get a weird counter force of it fighting your grip. Now do the same in sport. ...out of curiosity, what your max speed, all time? DJI advertise 50kmh...I hit about 75kmh. Out of my 161 flights, 270 km flown...guess during which of my flights I hit the top score ever with my drone for speed?

1537856054074.png
 
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lmel2005

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May 15, 2018
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If you stop motors midflight, spark will probably fall like a brick, in a way that eliminates air resistance.
So, it will fall with heavy battery facing down, and props almost vertical to the ground, and of course props cannot autorotate this way.
 
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SIDEHACK

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Hairdryer... Allow me to to laugh. :DYou did see the word TORNADO right!!!!! :eek:
Here's another interesting thing I found that gave me more insight about this drone. Send the spark up when you get the P-GPS lock, not in sport but normal, then bring it down to a level you can catch it from under without the bottom sensor correcting it away. Then rock it slowly side to side, front to back, enough so you clearely hear the props spin faster but not so much as to geting them stopped...you'll get a weird counter force of it fighting your grip. Now do the same in sport. ...out of curiosity, what your max speed, all time? DJI advertise 50kmh...I hit about 75kmh. Out of my 161 flights, 270 km flown...guess during which of my flights I hit the top score ever with my drone for speed?

View attachment 6986
HA HA!! I think you and I are looking at two different things.I only have about30 or so flights on my Spark and I've never flown where I had enough room to try top speed runs. I was curious about Chips observation of
the props rotating on the way down on his Spark without power. I can't wrap my brain around how that's possible with the folding props.
BTW Imel2005; The Spark's COG is as close to center as I can measure. It might wobble if the power failure occurred while moving. If the battery fell out then it would be nose heavy and all bets are off.
I bought a battery retainer so I no longer have to worry about a dropped battery. I discovered that 2 of my 6 batteries have short clips and I've just been lucky.
 
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