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I want to know more about this drone that was supposedly pestering an aircraft during firefighting operations. 10,000 ft altitude is quite high; if it was a qu

I want to know more about this drone that was supposedly pestering an aircraft during firefighting operations. 10,000 ft altitude is quite high; if it was a quad-copter type thing, I've got my doubts that it could make it to that altitude at all, much less maintain that altitude for any length of time. I'm going to assume that anything flying higher than ~15,000 ft is a military drone, and the FAA using these particular sightings to cast aspersions at private individuals is dishonest. Including incidents involving drones operated by the police is also pretty sketchy. Media are parroting this crap uncritically; I hope more of them find some gumption and ask a question or two. I can see where drones are potentially a problem, especially considering that they are only getting better/cheaper; but this sham-press release thing from the FAA appears to be scaremongering and it deserves ridicule. Links to both the FAA's press release and the AMA's response in this AMA blog post. http://amablog.modelaircraft.org/amagov/2015/09/14/ama-responds-to-the-faas-drone-sighting-report/ http://amablog.modelaircraft.org/amagov/2015/09/14/ama-respo...

lsaferite 11y ago
I don't doubt a quad copter could hit 10k feet, but I do doubt many people would go that high. The only way to control that would be via a remote telemetry and/or video link or via strict autonomous programming. A standard 250 class quad could likely hit that 3km in 1.5-3 minutes under full power. I know from my time build and flying that a flight time for a quad hovered (hah) around 15-20 minutes on average. That leaves 9-12 minutes of loiter time as max. Then you need to factor in the power cost of stabilizing the aircraft at the height. The wind will be shoving it around so the FC will need to be constantly fighting for position hold. I'd really love to see the math on the probability of a tiny quad intersecting the flight path of a firefighting aircraft at 3km altitude though. They are small and that's a LOT of open space. I can barely spot one against the open sky at a few hundred feet up. If these guys spotted one they must have amazing superhuman vision or amazing luck to have come within a very close distance. Personally I put most of the sightings into the mass-hysteria camp. I know there are idiots out there flying in controlled space, but I also think things are being blown way out of proportion. Edit: I found a site that did the speed/climd rate calculations. My numbers are bit off. The DJI, a common platform, could hit 3km in about 5.5 minutes and a 250 racing quad could do it in about 5. With about 20 minutes of battery power that leaves maybe 5-10 minutes of loiter time. DJI Phantom 2 Vision+: flight speed of 17 m/s (61 km/h) and a maximum climbing rate of 9 m/s 250 FPV Racing Quad: maximum flight speed of 18.5 m/s (67 km/h) and a maximum climbing rate of 10 m/s source: http://bpmsg.com/flight-speed-of-a-quadcopter/ http://bpmsg.com/flight-speed-of-a-quadcopter/
- fnordfnordfnord 11y ago
  10,000 ft has to be above or near the "service ceiling" of what a quad copter is even capable of. As altitude increases, air density decreases. The copter will have to work very hard, and will have less control force available. I think you're over-estimating the available power of a quad copter. I think it's a certainty that one would/should have a video system for operating without line-of-sight. Video systems are common in high-end equipment. >Personally I put most of the sightings into the mass-hysteria camp. I know there are idiots out there flying in controlled space, but I also think things are being blown way out of proportion. Yeah. Agreed. >>I found a site that did the speed/climd rate calculations. My numbers are bit off. The DJI, a common platform, could hit 3km in about 5.5 minutes and a 250 racing quad could do it in about 5. With about 20 minutes of battery power that leaves maybe 5-10 minutes of loiter time. 10,000 ft seems right at the edge of what the things can even do. They aren't going to be stable or easy to fly/land like a fixed wing aircraft would. edit: forgot part of my post. >I'd really love to see the math on the probability of a tiny quad intersecting the flight path of a firefighting aircraft at 3km altitude though. They are small and that's a LOT of open space. "Big Sky" theory doesn't give me as much comfort as it ought to. >I can barely spot one against the open sky at a few hundred feet up. If these guys spotted one they must have amazing superhuman vision or amazing luck to have come within a very close distance. This. I have a difficult time spotting full-sized aircraft in the air, and I have pretty good vision.
  - votingprawn 11y ago
    > 10,000 ft has to be above or near the "service ceiling" of what a quad copter is even capable of. As altitude increases, air density decreases. Its "only" a 25% reduction in density, you can still get a fair amount of flying done at that altitude. My colleagues have been to Ecuador twice for field work and had no issues flying quads in Quito (9,300ft), no need to change control gains or anything like that. So I know its perfectly possible.
- zobzu 11y ago
  250mm quads fly 3-7mins and going straight up is not hovering, it takes a lot of power. I fear you dont know what you're talking about. Basically you can go 3k up then stay a minute and free fall down. Bigger quads can fly longer - albeit going up always takes most energy and many big quads also need energy to go down / can't free fall without crash
votingprawn 11y ago
There is some confusion in this particular case stemming from the difference between altitude above sea level and above ground level. The UAV in question was spotted at ~10,000ft above sea level, but it was only about 800-900ft above the local ground level at the time.
- fnordfnordfnord 11y ago
  There is no confusion. I assumed 10,000 ft above sea level. Starting at 9,000 ft doesn't help much. The air is quite thin at 10,000 ft; many small general aviation aircraft have difficulty reaching that altitude. Here is a YT video showing a few minutes of someone's drone flight allegedly at that altitude. It doesn't appear to me that sustained flight for any reasonable duration is possible with that particular drone, nor do I expect any/many other drones to perform much better. https://www.youtube.com/watch?v=WnnlAS5Zzfg https://www.youtube.com/watch?v=WnnlAS5Zzfg
  - votingprawn 11y ago
    Apologies, your phrasing "make it to that altitude" made me think otherwise! Multi-rotors using BLDC motors cannot really be compared to small general aviation aircraft with infernal combustion engines. "Reasonable duration" is a nebulous phrase. Some of the airframe configurations we use here couldn't manage more than about 10 minutes at 100ft, whereas others could quite happily carry a gopro at 10,000ft for 10 minutes (assuming it didn't have to climb from sea level!)
    - fnordfnordfnord 11y ago
      re: my phrasing, I did assume that the drone pilot in question started from a much lower (unknown to me) altitude. >Multi-rotors using BLDC motors cannot really be It's got nothing to do with the type of motor or fuel. >"Reasonably duration" is a nebulous phrase. So So is "quite happily carry". I'll admit that it appears that it's not impossible for such a flight, but I don't agree that any drone is "happily carrying" anything at that altitude.
hydrogen18 11y ago
Forget 10,000 ft above sea level. The article quotes one incident as occurring at 51,000 ft. 51,000 ft is a crazy high altitude. Exactly what does the FAA think hobby kits include now? A complete knock down kit for a RQ-4 Global Hawk?
- fnordfnordfnord 11y ago
  Agreed. FL 510 is right out. Or else I'm expecting to hear a joke about a drone radioing in to ATC to request a groundspeed check any minute. edit: corrected post, see reply below.
  - gbin 11y ago
    This is FL510 You can get ballons to fly that high but not much anything else at an affordable price.
    - fnordfnordfnord 11y ago
      my mistake, thanks for the correction.
- Vexs 11y ago
  I don't even think quadcopters could produce 20% thrust at that height... which is pretty bad as consumer quads have something like a 2:1 thrust/weight ratio, maybe 3:1. High quality racing quads can get 8:1, but those have tiny batteries.
dirktheman 11y ago
This one hits the 12,000ft mark at around 8:30 minutes: https://www.youtube.com/watch?v=LKARaE51SPo https://www.youtube.com/watch?v=LKARaE51SPo Thing is, I seriously doubt many people fly their quadcopters that high. It's not much fun (not more fun than, say, 500ft), you don't have line of sight, and the wind will blow it away so if you don't track where you're going you're likely to lose your craft. Plus at that range, we're talking some serious long-range equipment. Ready-to-fly consumer drones max out at approx. 1 mile range. If you buy this stuff, you probably understand (you should!) what you're doing. It's possible alright, but not very likely.

lsaferite 11y ago

I don't doubt a quad copter could hit 10k feet, but I do doubt many people would go that high. The only way to control that would be via a remote telemetry and/or video link or via strict autonomous programming. A standard 250 class quad could likely hit that 3km in 1.5-3 minutes under full power. I know from my time build and flying that a flight time for a quad hovered (hah) around 15-20 minutes on average. That leaves 9-12 minutes of loiter time as max. Then you need to factor in the power cost of stabilizing the aircraft at the height. The wind will be shoving it around so the FC will need to be constantly fighting for position hold. I'd really love to see the math on the probability of a tiny quad intersecting the flight path of a firefighting aircraft at 3km altitude though. They are small and that's a LOT of open space. I can barely spot one against the open sky at a few hundred feet up. If these guys spotted one they must have amazing superhuman vision or amazing luck to have come within a very close distance. Personally I put most of the sightings into the mass-hysteria camp. I know there are idiots out there flying in controlled space, but I also think things are being blown way out of proportion. Edit: I found a site that did the speed/climd rate calculations. My numbers are bit off. The DJI, a common platform, could hit 3km in about 5.5 minutes and a 250 racing quad could do it in about 5. With about 20 minutes of battery power that leaves maybe 5-10 minutes of loiter time. DJI Phantom 2 Vision+: flight speed of 17 m/s (61 km/h) and a maximum climbing rate of 9 m/s 250 FPV Racing Quad: maximum flight speed of 18.5 m/s (67 km/h) and a maximum climbing rate of 10 m/s source: http://bpmsg.com/flight-speed-of-a-quadcopter/ http://bpmsg.com/flight-speed-of-a-quadcopter/

fnordfnordfnord 11y ago
10,000 ft has to be above or near the "service ceiling" of what a quad copter is even capable of. As altitude increases, air density decreases. The copter will have to work very hard, and will have less control force available. I think you're over-estimating the available power of a quad copter. I think it's a certainty that one would/should have a video system for operating without line-of-sight. Video systems are common in high-end equipment. >Personally I put most of the sightings into the mass-hysteria camp. I know there are idiots out there flying in controlled space, but I also think things are being blown way out of proportion. Yeah. Agreed. >>I found a site that did the speed/climd rate calculations. My numbers are bit off. The DJI, a common platform, could hit 3km in about 5.5 minutes and a 250 racing quad could do it in about 5. With about 20 minutes of battery power that leaves maybe 5-10 minutes of loiter time. 10,000 ft seems right at the edge of what the things can even do. They aren't going to be stable or easy to fly/land like a fixed wing aircraft would. edit: forgot part of my post. >I'd really love to see the math on the probability of a tiny quad intersecting the flight path of a firefighting aircraft at 3km altitude though. They are small and that's a LOT of open space. "Big Sky" theory doesn't give me as much comfort as it ought to. >I can barely spot one against the open sky at a few hundred feet up. If these guys spotted one they must have amazing superhuman vision or amazing luck to have come within a very close distance. This. I have a difficult time spotting full-sized aircraft in the air, and I have pretty good vision.
- votingprawn 11y ago
  > 10,000 ft has to be above or near the "service ceiling" of what a quad copter is even capable of. As altitude increases, air density decreases. Its "only" a 25% reduction in density, you can still get a fair amount of flying done at that altitude. My colleagues have been to Ecuador twice for field work and had no issues flying quads in Quito (9,300ft), no need to change control gains or anything like that. So I know its perfectly possible.
zobzu 11y ago
250mm quads fly 3-7mins and going straight up is not hovering, it takes a lot of power. I fear you dont know what you're talking about. Basically you can go 3k up then stay a minute and free fall down. Bigger quads can fly longer - albeit going up always takes most energy and many big quads also need energy to go down / can't free fall without crash

votingprawn 11y ago

There is some confusion in this particular case stemming from the difference between altitude above sea level and above ground level. The UAV in question was spotted at ~10,000ft above sea level, but it was only about 800-900ft above the local ground level at the time.

fnordfnordfnord 11y ago
There is no confusion. I assumed 10,000 ft above sea level. Starting at 9,000 ft doesn't help much. The air is quite thin at 10,000 ft; many small general aviation aircraft have difficulty reaching that altitude. Here is a YT video showing a few minutes of someone's drone flight allegedly at that altitude. It doesn't appear to me that sustained flight for any reasonable duration is possible with that particular drone, nor do I expect any/many other drones to perform much better. https://www.youtube.com/watch?v=WnnlAS5Zzfg https://www.youtube.com/watch?v=WnnlAS5Zzfg
- votingprawn 11y ago
  Apologies, your phrasing "make it to that altitude" made me think otherwise! Multi-rotors using BLDC motors cannot really be compared to small general aviation aircraft with infernal combustion engines. "Reasonable duration" is a nebulous phrase. Some of the airframe configurations we use here couldn't manage more than about 10 minutes at 100ft, whereas others could quite happily carry a gopro at 10,000ft for 10 minutes (assuming it didn't have to climb from sea level!)
  - fnordfnordfnord 11y ago
    re: my phrasing, I did assume that the drone pilot in question started from a much lower (unknown to me) altitude. >Multi-rotors using BLDC motors cannot really be It's got nothing to do with the type of motor or fuel. >"Reasonably duration" is a nebulous phrase. So So is "quite happily carry". I'll admit that it appears that it's not impossible for such a flight, but I don't agree that any drone is "happily carrying" anything at that altitude.

hydrogen18 11y ago

Forget 10,000 ft above sea level. The article quotes one incident as occurring at 51,000 ft. 51,000 ft is a crazy high altitude. Exactly what does the FAA think hobby kits include now? A complete knock down kit for a RQ-4 Global Hawk?

fnordfnordfnord 11y ago
Agreed. FL 510 is right out. Or else I'm expecting to hear a joke about a drone radioing in to ATC to request a groundspeed check any minute. edit: corrected post, see reply below.
- gbin 11y ago
  This is FL510 You can get ballons to fly that high but not much anything else at an affordable price.
  - fnordfnordfnord 11y ago
    my mistake, thanks for the correction.
Vexs 11y ago
I don't even think quadcopters could produce 20% thrust at that height... which is pretty bad as consumer quads have something like a 2:1 thrust/weight ratio, maybe 3:1. High quality racing quads can get 8:1, but those have tiny batteries.

dirktheman 11y ago

This one hits the 12,000ft mark at around 8:30 minutes: https://www.youtube.com/watch?v=LKARaE51SPo https://www.youtube.com/watch?v=LKARaE51SPo Thing is, I seriously doubt many people fly their quadcopters that high. It's not much fun (not more fun than, say, 500ft), you don't have line of sight, and the wind will blow it away so if you don't track where you're going you're likely to lose your craft. Plus at that range, we're talking some serious long-range equipment. Ready-to-fly consumer drones max out at approx. 1 mile range. If you buy this stuff, you probably understand (you should!) what you're doing. It's possible alright, but not very likely.