7 ms·

My one concern with all these new drones that keep popping up is the flight duration. This one is among the worst I've seen: "... flight endurance, which is cu

My one concern with all these new drones that keep popping up is the flight duration. This one is among the worst I've seen: "... flight endurance, which is currently around 12 minutes". Others in the market don't seem to be much better, clocking around 30mins - 1hr per flight. Are any of these able to fly a preset, waypoint path for two or more hours? I don't want to be thinking about the landing just as soon as it gets up in the air.

steckerbrett 11y ago
The limit is the batteries mostly. You won't be seeing that sort of performance from an electrically powered helicopter without some drastic improvements in battery power density.
- mrec 11y ago
  Or drastic reductions in weight. I don't know which is more likely. I suppose if it gets too light then wind becomes more of a problem.
- TheSisb2 11y ago
  Couldn't you add more battery? Sure it's more weight but I'd imagine more battery would result in slightly higher power output and an increase in flight duration. The added weight would help against wind gusts too.
  - steckerbrett 11y ago
    Absolutely. This is being pitched as a consumer product you can throw in your bag though, which has definite size and usability constraints. For safety you really don't want people carrying around a backpack stuffed with Lithium Polymer cells either, that's a disaster waiting to happen if someone falls over backwards and pierces one of the cells.
  - lambda 11y ago
    Let's work out how that would work, in a simplified model of the world. Let's say you have a 1000mAh battery at 10V that weighs 100g (these numbers have all been made round for purposes of easier arithmetic). Everything else on your drone is weightless, and your motors have perfect efficiency. To keep this aloft, you need to overcome 9.8 m/s^2 that is applied by Earth's gravity; but since we're simplifying things, let's just round that to 10 m/s^2. 10 m/s^2 * 100g is 1 N, which means it requires 1 W of power to keep that battery aloft (resist the force of gravity). 1Ah * 10 V = 10 Wh, so that means you could stay aloft for 10 h (remember, these numbers are unrealistic, we have ignored any kind of efficiency, or the weight of the rest of the drone, etc). So, lets use two batteries. Now we have 20 Wh of energy available, but we're holding up 200g of battery, which requires 2 W of power to stay aloft, so again, we can stay aloft for just 10 h. And remember, all of this was ignoring any notion of efficiency or the weight of any other part of the craft to support this. As you increase the weight, motors will need to get more powerful to be able to actually keep it aloft, which means they need to get bigger, which is extra weight that you need to support that isn't giving you any extra energy. So the real world is actually even worse than our idealized model; as you add on more battery, only a fraction of the increase in weight adds more energy, so you will actually see shorter flight times. Now, of course, there are designs for which increasing the amount of battery can lead to increased flight times. If the power supplied by the motors is sufficient to sustain the extra weight, so they don't need to be scaled up, then increasing the amount of battery relative to the rest of the weight of the craft can lead to higher efficiency as there is less relative "dead weight" (weight besides the batteries, that is not carrying energy). But that can only take you so far, which is why the flight times of drones plateau at a certain point and you can't fix it by just adding more battery. This is why you don't see electric helicopters carrying people. The energy to weight ratio for batteries is too low; only fossil fuels have a sufficient energy density.
    - gus_massa 11y ago
      I agree with your general idea, more than half an hour is not posible with the current technology. But I think this conversion is wrong: > let's just round that to 10 m/s^2. 10 m/s^2 100g is 1 N, which means it requires 1 W of power to keep that battery aloft* To transform some force into power, you need to multiply it by a speed (m/s). My favorite example is that a brick resting on a table can "hover" without spending any power (for a weird definition of "hovering"). I think the correct calculation involves the density of the air, to estimate the speed of the air that must be pushed down.
lambda 11y ago
Nope. We're pretty much limited by battery technology on that front; you need bigger batteries to provide more power, but those bigger batteries mean more weight, which means more power needed just to stay aloft. For a battery powered multicopter, I think an hour or so is about the highest you can get (I don't think I've seen any that claim over 40 minutes), and as you point out, most drones are closer to the 15 to 20 minute range. Of course, there are other designs like fixed wing planes which can be a bit more efficient though more complicated to navigate in confined spaces and without the ability to hover, and you can use internal combustion engines which can get you much longer flight times due to the higher energy density of their power source. But I don't think you're going to find any of the affordable, battery powered multicopters that get you anything over an hour (and even then, I would set my expectations at more like a half-hour for anything affordable in realistic conditions).
- toomuchtodo 11y ago
  Wireless power transmission via laser: > Stalker is a small, silent UAS used by Special Operations Forces since 2006 to perform intelligence, surveillance and reconnaissance missions. In a recent wind tunnel test, the UAS demonstrated 48 hours of continuous flight powered by this innovative laser system. > Demonstrated net positive power to Stalker in flight, at ranges up to 600 meters. > The beam director tracked the receiver for long periods, with centimeter accuracy at 500 meters, despite turbulence and aircraft maneuvers. http://lasermotive.com/products/uav-power-links/ http://lasermotive.com/products/uav-power-links/ Note they first successfully demonstrated this outdoors 3 years ago: http://www.lockheedmartin.com/us/news/press-releases/2012/august/120807ae_uas-laser-powered.html http://www.lockheedmartin.com/us/news/press-releases/2012/au...
  - tomswartz07 11y ago
    This is genuinely awesome and I'm excited to see it's applications in future products. HOWEVER: I don't think it's ready for 'consumer grade' things just yet. It's one thing to have it in a controlled wind-tunnel for 48 hours, it's completely different than having it outside and in variable wind, dirt, dust, other objects, etc. Honestly, I can't imagine my luddite brother or father wrapping their minds around this just yet: "So, I point the laser at this? Why can't I just use a flashlight? Can I use the laser to charge my phone?"
digikata 11y ago
If you need long endurance, then you likely need a fixed-wing system. In general, the efficiency goes: fixed wing > complex single rotor (helicopter) > multi-rotor (e.g. quadcoptor)
- IgorPartola 11y ago
  Don't forget lighter than air craft. A GoPro + weather balloon is pretty efficient.
  - xanderstrike 11y ago
    At the expense of maneuverability. It's worth mentioning that this is the trade off here. From least to most maneuverable: Weather balloon -> Fixed Wing -> Single rotor -> Multirotor
    - IgorPartola 11y ago
      Definitely. Now I want to build a blimp drone or a blone if you will just to give it a try :). I imagine a toroidal shaped ballon with a small propeller in the middle might actually do fairly well and would be less susceptible to sideways wind than a balloon.
      - MatthewMcDonald 11y ago
        This was posted in the discussion when the Lily was announced: http://hyperblimp.com/ http://hyperblimp.com/
  - digikata 11y ago
    Yes, definitely, but scaling volume to carry payload mass becomes inconvenient for casual use quickly. Cheating the calcs a bit and using the table here: http://www.chem.hawaii.edu/uham/lift.html http://www.chem.hawaii.edu/uham/lift.html A 3.5oz (~99gram) Go pro needs at least a 22in diameter spherical ballon filled with Helium. And unless you're ok with tethered use, you need to dedicate some power & mass to pointing & station keeping which increases the volume even more. For every gram of other capability you add, you're adding another liter of gas.
stephengillie 11y ago
The problem is you're relying solely on the propellers for lift. Batteries are heavy and only store a small amount of electricity. You need to attach a helium balloon or some other means of lift that doesn't require electricity. Some sort of miniaturized hot-air system might work as well.
- lsaferite 11y ago
  Might be an interesting idea for a UAV like this to include a mount point at the top where you could attach a helium balloon that could carry some percentage of the weight less that 100%. That reduction in weight would translate into longer run-time. Of course it also would reduce maneuverability.
dankohn1 11y ago
I think of most of the development of drones as being what Chris Anderson calls "the peace dividend of the smartphone wars" [0]. Most of the components -- batteries, processors, radios, cameras -- have benefited enormously from the billion smartphones made every year. Unfortunately, of that list, batteries have improved the least. [0] http://foreignpolicy.com/2013/04/29/epiphanies-from-chris-anderson/ http://foreignpolicy.com/2013/04/29/epiphanies-from-chris-an...
yincrash 11y ago
One way to mitigate this is with removable batteries, so you can replace them between scenes. Both the iris and this sprite both have that feature. The lily's battery does not appear to be removable.
return0 11y ago
would be nice if they could at least auto-home themselves to recharge

steckerbrett 11y ago

The limit is the batteries mostly. You won't be seeing that sort of performance from an electrically powered helicopter without some drastic improvements in battery power density.

mrec 11y ago
Or drastic reductions in weight. I don't know which is more likely. I suppose if it gets too light then wind becomes more of a problem.
TheSisb2 11y ago
Couldn't you add more battery? Sure it's more weight but I'd imagine more battery would result in slightly higher power output and an increase in flight duration. The added weight would help against wind gusts too.
- steckerbrett 11y ago
  Absolutely. This is being pitched as a consumer product you can throw in your bag though, which has definite size and usability constraints. For safety you really don't want people carrying around a backpack stuffed with Lithium Polymer cells either, that's a disaster waiting to happen if someone falls over backwards and pierces one of the cells.
- lambda 11y ago
  Let's work out how that would work, in a simplified model of the world. Let's say you have a 1000mAh battery at 10V that weighs 100g (these numbers have all been made round for purposes of easier arithmetic). Everything else on your drone is weightless, and your motors have perfect efficiency. To keep this aloft, you need to overcome 9.8 m/s^2 that is applied by Earth's gravity; but since we're simplifying things, let's just round that to 10 m/s^2. 10 m/s^2 * 100g is 1 N, which means it requires 1 W of power to keep that battery aloft (resist the force of gravity). 1Ah * 10 V = 10 Wh, so that means you could stay aloft for 10 h (remember, these numbers are unrealistic, we have ignored any kind of efficiency, or the weight of the rest of the drone, etc). So, lets use two batteries. Now we have 20 Wh of energy available, but we're holding up 200g of battery, which requires 2 W of power to stay aloft, so again, we can stay aloft for just 10 h. And remember, all of this was ignoring any notion of efficiency or the weight of any other part of the craft to support this. As you increase the weight, motors will need to get more powerful to be able to actually keep it aloft, which means they need to get bigger, which is extra weight that you need to support that isn't giving you any extra energy. So the real world is actually even worse than our idealized model; as you add on more battery, only a fraction of the increase in weight adds more energy, so you will actually see shorter flight times. Now, of course, there are designs for which increasing the amount of battery can lead to increased flight times. If the power supplied by the motors is sufficient to sustain the extra weight, so they don't need to be scaled up, then increasing the amount of battery relative to the rest of the weight of the craft can lead to higher efficiency as there is less relative "dead weight" (weight besides the batteries, that is not carrying energy). But that can only take you so far, which is why the flight times of drones plateau at a certain point and you can't fix it by just adding more battery. This is why you don't see electric helicopters carrying people. The energy to weight ratio for batteries is too low; only fossil fuels have a sufficient energy density.
  - gus_massa 11y ago
    I agree with your general idea, more than half an hour is not posible with the current technology. But I think this conversion is wrong: > let's just round that to 10 m/s^2. 10 m/s^2 100g is 1 N, which means it requires 1 W of power to keep that battery aloft* To transform some force into power, you need to multiply it by a speed (m/s). My favorite example is that a brick resting on a table can "hover" without spending any power (for a weird definition of "hovering"). I think the correct calculation involves the density of the air, to estimate the speed of the air that must be pushed down.

lambda 11y ago

Nope. We're pretty much limited by battery technology on that front; you need bigger batteries to provide more power, but those bigger batteries mean more weight, which means more power needed just to stay aloft. For a battery powered multicopter, I think an hour or so is about the highest you can get (I don't think I've seen any that claim over 40 minutes), and as you point out, most drones are closer to the 15 to 20 minute range. Of course, there are other designs like fixed wing planes which can be a bit more efficient though more complicated to navigate in confined spaces and without the ability to hover, and you can use internal combustion engines which can get you much longer flight times due to the higher energy density of their power source. But I don't think you're going to find any of the affordable, battery powered multicopters that get you anything over an hour (and even then, I would set my expectations at more like a half-hour for anything affordable in realistic conditions).

toomuchtodo 11y ago
Wireless power transmission via laser: > Stalker is a small, silent UAS used by Special Operations Forces since 2006 to perform intelligence, surveillance and reconnaissance missions. In a recent wind tunnel test, the UAS demonstrated 48 hours of continuous flight powered by this innovative laser system. > Demonstrated net positive power to Stalker in flight, at ranges up to 600 meters. > The beam director tracked the receiver for long periods, with centimeter accuracy at 500 meters, despite turbulence and aircraft maneuvers. http://lasermotive.com/products/uav-power-links/ http://lasermotive.com/products/uav-power-links/ Note they first successfully demonstrated this outdoors 3 years ago: http://www.lockheedmartin.com/us/news/press-releases/2012/august/120807ae_uas-laser-powered.html http://www.lockheedmartin.com/us/news/press-releases/2012/au...
- tomswartz07 11y ago
  This is genuinely awesome and I'm excited to see it's applications in future products. HOWEVER: I don't think it's ready for 'consumer grade' things just yet. It's one thing to have it in a controlled wind-tunnel for 48 hours, it's completely different than having it outside and in variable wind, dirt, dust, other objects, etc. Honestly, I can't imagine my luddite brother or father wrapping their minds around this just yet: "So, I point the laser at this? Why can't I just use a flashlight? Can I use the laser to charge my phone?"

digikata 11y ago

If you need long endurance, then you likely need a fixed-wing system. In general, the efficiency goes: fixed wing > complex single rotor (helicopter) > multi-rotor (e.g. quadcoptor)

IgorPartola 11y ago
Don't forget lighter than air craft. A GoPro + weather balloon is pretty efficient.
- xanderstrike 11y ago
  At the expense of maneuverability. It's worth mentioning that this is the trade off here. From least to most maneuverable: Weather balloon -> Fixed Wing -> Single rotor -> Multirotor
  - IgorPartola 11y ago
    Definitely. Now I want to build a blimp drone or a blone if you will just to give it a try :). I imagine a toroidal shaped ballon with a small propeller in the middle might actually do fairly well and would be less susceptible to sideways wind than a balloon.
    - MatthewMcDonald 11y ago
      This was posted in the discussion when the Lily was announced: http://hyperblimp.com/ http://hyperblimp.com/
- digikata 11y ago
  Yes, definitely, but scaling volume to carry payload mass becomes inconvenient for casual use quickly. Cheating the calcs a bit and using the table here: http://www.chem.hawaii.edu/uham/lift.html http://www.chem.hawaii.edu/uham/lift.html A 3.5oz (~99gram) Go pro needs at least a 22in diameter spherical ballon filled with Helium. And unless you're ok with tethered use, you need to dedicate some power & mass to pointing & station keeping which increases the volume even more. For every gram of other capability you add, you're adding another liter of gas.

stephengillie 11y ago

The problem is you're relying solely on the propellers for lift. Batteries are heavy and only store a small amount of electricity. You need to attach a helium balloon or some other means of lift that doesn't require electricity. Some sort of miniaturized hot-air system might work as well.

lsaferite 11y ago
Might be an interesting idea for a UAV like this to include a mount point at the top where you could attach a helium balloon that could carry some percentage of the weight less that 100%. That reduction in weight would translate into longer run-time. Of course it also would reduce maneuverability.

dankohn1 11y ago

I think of most of the development of drones as being what Chris Anderson calls "the peace dividend of the smartphone wars" [0]. Most of the components -- batteries, processors, radios, cameras -- have benefited enormously from the billion smartphones made every year. Unfortunately, of that list, batteries have improved the least. [0] http://foreignpolicy.com/2013/04/29/epiphanies-from-chris-anderson/ http://foreignpolicy.com/2013/04/29/epiphanies-from-chris-an...

yincrash 11y ago

One way to mitigate this is with removable batteries, so you can replace them between scenes. Both the iris and this sprite both have that feature. The lily's battery does not appear to be removable.

return0 11y ago

would be nice if they could at least auto-home themselves to recharge