Sprite: a different drone

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?"

How stealthy is this thing if it has a giant laser pointed at it the whole time?

Huh.

That's actually really interesting.

I have this vision of a large mother UAV with long loiter times that can laser target micro UAVs at much lower altitudes.

Yes, another approach is to not have to carry all of the energy with you. Solar charging is another possibility.

Most quadcopters aren't gas-powered because they rely on rapidly adjusting the speed of brushless motors attached to fixed-pitch props to control their attitude.

A few hobbyists have built gas quads with variable-pitch rotors, but the amount of mechanical complexity and hassle involved makes a similar nitro-powered single-rotor helicopter more appealing for most hobby applications (stunt flying etc).

As more novel designs that don't rely on precise motor speed control (for example, this one) come into play, I think gas motors will make a minor resurgence as people rediscover the energy density (and therefore flight time) they can achieve.

However, for most hobbyists, electric just makes more sense. It's usually quieter, works indoors, is generally a lot less of a pain in the ass to deal with (no need for starters, glow plugs, choke, adjusting mixture, engine maintenance, etc.), and is usually less heavily regulated.

For multirotors it's just very difficult and impractical to power them with gasoline engines. If you were to build a gas powered multirotor, you'd have to have a central engine connected to each motor by means of some complicated mechanical linkage. This would also mean you could no longer control the speeds of the motors individually, so you'd have to achieve lateral movement by pitching the propellers, like on a helicopter. All these things mean that it simply doesn't make sense to build a non-electric multirotor, it'd be massively expensive and inefficient you'd be better off going back to a helicopter.

In terms of fixed wing drones, the benefit of electric over gas is mainly ease of use I believe. It's a lot simpler for someone to charge a battery and just plug it in than it is for them to fill up canisters, refuel the engine and cope with the complexities of tweaking and starting an engine. That extra effort and learning curve isn't worth it for the slightly longer slight time.

For aerial mapping the go-to option is normally fixed wing drones, they can easily achieve 30-40 minutes of flight time and this is normally enough for those kind of applications.

Control and cost.

PWM motors can control their rotation very precisely unlike IC motors. That is one reason you see multicopter designs nowadays. You can quickly alter the torque. I didn't see how this design alters pitch or roll, but I know there were some coaxial experimental designs that can alter the torque in a single rotation to affect those axis. That is simply not possible with something powered by burning fuel. It might be possible to have a mixed system, using an internal combustion engine for primary lift and electronically controlled steering, but that would be a more complex system and the benefit isn't abundantly clear.

Size, noise, maintenance, predictability, simplicity, cost. Haven't seen a power/weight trade study of batteries vs engine+generator+fuel, but it may be closer than you think. There's a lot involved in a ICE power plant, and even if it did win, it'd have to be a pretty big machine compared to your average multirotor due to minimum scale on gasoline engine components.

There might be a market for large endurance multirotors, but apparently it's not obviously attractive.

Price and safety, I would bet.

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

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 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.

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.

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.

Precisely! Also When I first saw the post in hn. I immediately thought like a game graphic sprite. Not even the soda.

My understanding of law leaves lots to be desired, but wouldn't the trial, even if they won, be way too expensive? And there is always the risk of losing, Coca-Cola can certainly afford better lawyers.

> Soda and drones are not likely to be confused in the marketplace

This drone does look like a 2-liter [Sprite] bottle though :)

You didn't even click the link I provided, did you?

If you had clicked the link I provided, you might come to understand that since 1995, U.S. trademark law does not just work in the way you described, but also includes the concept of "dilution", where famous marks are protected by law even though there is zero chance of consumer confusion.

You're obviously new to HN!