Flying over towns and cities?

[Oingo Boingo]

Easy, Big Guy; don't bust a gut. The price tag of a drone doesn't qualify or disqualify it from being "pro". Even a "$10k and up" drone has not the redundancy of a manned aircraft and can come spiraling out of the sky like a wounded duck.

The Mavic is absolutely not toy-grade. I have toy-grade drones. There is obviously a huge difference. That said, they are all toys to some degree or another. Some are just a lot more sophisticated. But if you treat the Mavic like a toy, such as flying it without regard to the safety of others, then nobody will call it a toy. They'll call it a dangerous machine that should be heavily regulated.

Sorry cupcake, youre a bit misinformed there. Most of the hexa or octo copters can fly and stay in the air eve if they loose a motor or a blade. The DJI Matrice or 900 series even has a dual flight controller one could use. You as much as clip a twig with a phantom or mavic.... It falls like a brick

 

[Oingo Boingo]

Umbrella policy is a good thing to have. And I don't think a Mavic ever dropped like a rock because a battery came loose.

Perhaps read a few of the post on that topic.... You will be surprized. Be it the idiot flying the unit or not

 

[aesculus]

Ok, sweetheart so what you're saying is the cost and reliability of a drone is directly proportional to the number of motors? 6 motors - 4 motors = automatic redundancy. Got it.

 

[Yoshizakura]

Sorry cupcake, youre a bit misinformed there. Most of the hexa or octo copters can fly and stay in the air eve if they loose a motor or a blade. The DJI Matrice or 900 series even has a dual flight controller one could use. You as much as clip a twig with a phantom or mavic.... It falls like a brick

Yep, the smallest twig can and does cause a mavic to crash out of the sky. Luckily the twig in my case was 15 feet from me and 5 feet off the ground.

 

[AlanTheBeast]

I agree, that the onus of safety is on the pilot. A good pilot can fly ATTI when the GPS drops out, or CSC when in immediate danger of causing harm. They're also far less likely to get into such situations, as they plan ahead and assess risks (and are better at handling situations when they arise).

My comment was that the analogy for fixed wing aircraft just didn't work given the vast differences in categorisation. You can compare a pencil and a pen, but comparing all types of pencil against all types of pen is pointless.

It was only to point out that not all aircraft are equal in certification requirements even though they would seem to have to be given their passenger carrying role. Quibbling on an internet forum. Imagine that!

 

[Wombat55]

One thought however: I don't know if it's impossible for a quad to be programmed to fly with 3 rotors if one fails - or at least reduce descent speed in that instance.

I doubt that flying with three is possible. There would be a torque imbalance with two of the props spinning either clockwise or counterclockwise, and the remaining third prop spinning in the opposite direction. And although it might be possible to balance out the torques by spinning the third prop relatively fast compared to the other two props, that would almost certainly conflict with the requirement to balance the thrusts of the three props to keep the drone flying upright.

Probably the best available option with three working props would be to sacrifice torque balance while trying to maintain the drone flying upright so that the spinning drone comes straight down to the ground as gently as possible. That would at least minimize the chances of someone on the ground getting injured by a falling drone.

 

[AyeYo]

I doubt that flying with three is possible. There would be a torque imbalance with two of the props spinning either clockwise or counterclockwise, and the remaining third prop spinning in the opposite direction. And although it might be possible to balance out the torques by spinning the third prop relatively fast compared to the other two props, that would almost certainly conflict with the requirement to balance the thrusts of the three props to keep the drone upright.

Bingo

 

[AlanTheBeast]

I doubt that flying with three is possible. There would be a torque imbalance with two of the props spinning either clockwise or counterclockwise, and the remaining third prop spinning in the opposite direction. And although it might be possible to balance out the torques by spinning the third prop relatively fast compared to the other two props, that would almost certainly conflict with the requirement to balance the thrusts of the three props to keep the drone flying upright.

Probably the best available option with three working props would be to sacrifice torque balance while trying to maintain the drone flying upright so that the spinning drone comes straight down to the ground as gently as possible. That would at least minimize the chances of someone on the ground getting injured by a falling drone.

That's sort of where I was going - if not complete recovery then at least reduced, er, impact.

 

[frankiez]

I doubt that flying with three is possible. There would be a torque imbalance with two of the props spinning either clockwise or counterclockwise, and the remaining third prop spinning in the opposite direction. And although it might be possible to balance out the torques by spinning the third prop relatively fast compared to the other two props, that would almost certainly conflict with the requirement to balance the thrusts of the three props to keep the drone flying upright.

Probably the best available option with three working props would be to sacrifice torque balance while trying to maintain the drone flying upright so that the spinning drone comes straight down to the ground as gently as possible. That would at least minimize the chances of someone on the ground getting injured by a falling drone.

There is a YouTube video of the mavic that some guy posted where he subjected his mavic to all different abuse. He threw things at it, he put a prop on loosely so it came off in flight, he hung a 16 oz water bottle from one Arm, etc.

Very interesting to see.

 

[andy966]

Well its in no way professional grade

Yeah, it's definitely not a Matrice. Matrice 200 Series: Increased Aerial Efficiency

 

[NickB]

I had a prop snap on a hexa, it went mental till i switched to manual mode and managed to get it down ok...fitted graupner elekro props after and had 3 years trouble free.

 

[kona]

The Mavic is safer than a car. Mandate liability insurance, which at current accident rates will cost cents, as well as flyer certification requirements and that's really all there needs to be said about this topic. Not flying over populated areas would be as fascist a solution has not driving in populated areas.

 

[BorisTheSpider]

I leave it as an exercise to the reader to spot the correlation between attitudes to flying uncertified aircraft over the heads of unwitting bystanders, and standards of spelling and punctuation. You may feel free to further extrapolate about what that might say about attention to detail, and who you'd rather have flying stuff near you and your loved ones.

 

[halley]

All this "sweetheart, cupcake" stuff is getting pretty rude. Stop and take a walk, and remember this is a public forum for reasonable respectful debate. If you can't avoid taking the bait, use the Ignore feature of the forum.

 

[Wombat55]

Most of the hexa or octo copters can fly and stay in the air eve if they loose a motor or a blade. The DJI Matrice or 900 series even has a dual flight controller one could use. You as much as clip a twig with a phantom or mavic.... It falls like a brick

Not sure what hex-copters you're referring to. I checked a RC forum to see what they say, and here are some of their comments:

........
"I own a quad (DJI F450) and a Hex (XA Hexa)... I can tell you the following:"

"1) In terms of stability in the wind, the Hexa wins HANDS DOWN. The little quad gets pushed all over the place and becomes really wobbly in high wind. The Hexa, on the other hand, remains quite stable no matter what (it just gets pushed around)."

"2) In terms of ability to withstand a failure, they are both terrible. The quad and the hexa will both crash immediately if they lose a motor or a prop. (I've experienced both on both)."

.........

"Y6 is no more redundant than a flat 6 and is less stable and more inefficient to boot. In fact I'd go so far and say a Y6 is less stable than a quad, at least the one's I've seen were. If your gonna fly over water or crashing is more than an inconvience then octo is the wise choice."

"A flat 6 will give you more stability and lifting power than a quad, and marginal redundancy as long as your just hovering around. Lose a prop or motor while flying normally with any forward speed and a hex or Y6 is unlikley to save your bacon. Lose a prop or motor on a flat octo and you may not notice till you land."
........
Hexcopter vs quadcopter - wind and motor failures - RC Groups

I think that in principle it should be possible to engineer a hex-copter so that it has greater redundancy than a quadcopter to a prop or motor failures. No argument about that. But it appears that in practice many drone manufacturers simply haven't gone through the trouble of trying to implement prop or motor failure identification and correction algorithms into their flight control software.

Oh, and I spotted another very relevant post on the RC Group forum linked to above. I think that post by "Ernie" pretty much sums up the situation:
.......
"The flight controllers don't know if a prop has busted or a motor is seizing up, there are no feedback sensors. All they know is the copter isn't going where the FC wants it too, so it will still try and rev up a dysfunctional motor/prop instead of taking it out of the pool of available resources."

"In the future, it might be nice to build multi-copters with feedback sensors, optical, hall effect, whatever, just something so the flight controller knows the prop is still there and how fast it's spinning."

"Currently, only a human pilot knows there is a problem and compensates properly. If you have a zillion motors, the loss of one or two doesn't mean much, and the dumb flight controllers can deal with that."

 

[Oingo Boingo]

Not sure what hex-copters you're referring to. I checked a RC forum to see what they say, and here are some of their comments:

........
"I own a quad (DJI F450) and a Hex (XA Hexa)... I can tell you the following:"

"1) In terms of stability in the wind, the Hexa wins HANDS DOWN. The little quad gets pushed all over the place and becomes really wobbly in high wind. The Hexa, on the other hand, remains quite stable no matter what (it just gets pushed around)."

"2) In terms of ability to withstand a failure, they are both terrible. The quad and the hexa will both crash immediately if they lose a motor or a prop. (I've experienced both on both)."

.........

"Y6 is no more redundant than a flat 6 and is less stable and more inefficient to boot. In fact I'd go so far and say a Y6 is less stable than a quad, at least the one's I've seen were. If your gonna fly over water or crashing is more than an inconvience then octo is the wise choice."

"A flat 6 will give you more stability and lifting power than a quad, and marginal redundancy as long as your just hovering around. Lose a prop or motor while flying normally with any forward speed and a hex or Y6 is unlikley to save your bacon. Lose a prop or motor on a flat octo and you may not notice till you land."
........
Hexcopter vs quadcopter - wind and motor failures - RC Groups

I think that in principle it should be possible to engineer a hex-copter so that it has greater redundancy than a quadcopter to a prop or motor failures. No argument about that. But it appears that in practice many drone manufacturers simply haven't gone through the trouble of trying to implement prop or motor failure identification and correction algorithms into their flight control software.

Oh, and I spotted another very relevant post on the RC Group forum linked to above. I think that post by "Ernie" pretty much sums up the situation:
.......
"The flight controllers don't know if a prop has busted or a motor is seizing up, there are no feedback sensors. All they know is the copter isn't going where the FC wants it too, so it will still try and rev up a dysfunctional motor/prop instead of taking it out of the pool of available resources."

"In the future, it might be nice to build multi-copters with feedback sensors, optical, hall effect, whatever, just something so the flight controller knows the prop is still there and how fast it's spinning."

"Currently, only a human pilot knows there is a problem and compensates properly. If you have a zillion motors, the loss of one or two doesn't mean much, and the dumb flight controllers can deal with that."

Let me clarify - When I say stay in the Air - I am not refering to flying on as everything is all Hunky Dory ! If the guy had a hexa or an Octo that just fell out of a sky because of a motor something in his flight control was not set correctly - I have had a Early DJI S900 have a motor failure - It wasnt a complete failure as in the motor CUT OUT - but is was serious failure as in one of the bearings in the motor packed up and the motor speed was down probably 70 - 80%. The drone was fitted with E1200 Pro Tuned Propulsion kit. I was not piloting, my partner was, hemanged to get the drone safely. So herewith the point - Its not a laaaaaadi daaaa oh its such a nice day to fly - redundency system, BUT its a system that allows you to get the drone down in a semicontrolled way . If you have even flown helis you should know what an Autoration is - Is a similar move - Its not ideal - But hey It doesnt go from flying mode to hitting the ground in brick mode where you have NO control - I was on a shoot where the same has happened with a Vespa Xyris 8 - I Specialized commercial shot in the Hogsback Forest area of South Africa - The drone hit the end of a small branch in pine forest. The drone was carrying a Blackmagic URSA Mini with lens kit No we could just continue flying but the drone could come down safely and there was no damage - Was it a quadcopter it would have been bye bye - drop it like its hot. So there are my HANDS ON experiences with Hexa and Octos. If the guy crashes an octo after a motor goes - Either - A) He is a pretty bad pilot - or B) He is using a cheapie flight controller.

The top of the range NAZA systems are known to handle motor failures the best - The new APM series is caching on but not quite there. The new PIXHAWK has been known to react well but I have not had experience with PIXHAWK AT ALL !

I might just add that the guys that flew both the Hex and Octo were seasoned 3D Heli pilots and they both compete in 3D Acro Flying tourneys. SO they are no rookies. Both of them built their own kit as well.

So when you talk redundency - Its not a keep on flying like everything is normal situation - Its a get the drone down safely in a semi controlled state

 

[Oingo Boingo]

I had a prop snap on a hexa, it went mental till i switched to manual mode and managed to get it down ok...fitted graupner elekro props after and had 3 years trouble free.

Hey Nick what flight controller are you running on the Hex - ?

 

[NickB]

It was a naza m v2.

 

[stratos]

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I agree though, the risk from a falling drone is much higher.

Using Energy of falling object to do a crude calculation of a 0.7kg falling mavic after losing a prop 100M up results in an impact velocity of 98MPH and an energy of around 680 joules.

That's around the muzzle energy of a .357 magnum: http://wredlich.com/ny/wp-content/uploads/2013/01/muzzle-energy.png

Energy doesn't tell the whole story of course, so of course they won't do exactly the same thing when they hit you, but both will definitely mess up your day and if anyone doubts that a falling mavic will do real damage then feel free to fly yours into your head at 100 miles per hour and see what happens.

Ive seen actual bird heavier than our drones.
Ive never seen in the news someone killed being hit bit a falling bird.

But as always I can be completely wrong.

 

[Wombat55]

Ive seen actual bird heavier than our drones.
Ive never seen in the news someone killed being hit bit a falling bird.

But as always I can be completely wrong.

To weigh as much as a Mavic, you're talking about a rather big bird such as a large crow, or a Western Seagull like we have here in the San Francisco Bay Area. Yeah, I wouldn't want to be hit on the head by a Western Seagull that suddenly fell out of the air, but it would be better than getting hit on the head by a falling Mavic. A seagull is mostly softer tissue surrounded by feathers. A Mavic is mostly hard metal and plastic. Also, since the overall mass density of a seagull is less than that of a Mavic, the terminal velocity due to air resistance of a falling seagull is going to be significantly less than the terminal velocity of a falling Mavic.