[jleahy]

That's because of the energy density (per mass) of Li-Ion batteries. You basically hit a wall at 20 minutes that's very hard to push past (it almost feels like a law of physics).

But maybe they're using non-rechargeable batteries: zinc-air or lithium-iron-disulfide (ie. a 'lithium' AA battery) or something else? Trade offs are different for military.

[NovemberWhiskey]

The amount of batteries soldiers need to carry is ridiculous; a 72 hour patrol load out includes up to 25 lbs of batteries already!

[jleahy]

Yes but there are no convenient charging points, if the battery runs out then you need to replace it, not charge it. All the more reason to throw used batteries away (they’re cheap and it’s less to carry).

[herewulf]

Military radio batteries are typically rechargable and they are heavy.

[plouffy]

Based on the info sheet "A quick change battery" would suggest they went for the non-rechargeable route.

[dimatura]

I don't think it necessarily means non-rechargeable. Since charging usually takes a long time, generally in the field you carry a bunch of batteries charged ahead of time and swap them as needed.

[azalemeth]

The classic example of a good military-only battery would be those using molten salts as an electrolyte (typically at 150-500 ºC) [1]. Very high energy density (around 74 Ahr/kg [2] compared to LiPo's ~50 Ahr/kg [3]) and very high power density. Not finger friendly.

[1] http://en.wikipedia.org/wiki/Molten_salt_battery [2] https://global-sei.com/technology/tr/bn76/pdf/76-06.pdf [3] https://blog.ampow.com/lipo-battery-size-chart/

[Someone]

If one could make such a battery small enough for this drone, I expect you would need all its power to keep the salt molten.

[bowmessage]

Don't a lot of the DJI models have a ~30 minute flight time? Point taken though, that there's a wall we hit with current battery tech.

[extropy]

The DJI drones that can do that are significantly larger. A 250 gram DJI mavic mini can do 30 minutes and with significantly larger propellers.

The efficiency goes down with smaller blade sizes (more losses to vortexes) so from the photo 20 min is the max to expect with regular lipo batteries.

[Tepix]

The Mini 2 manages 31 minutes at 249g and it features a 3 axis gimbal for the camera. This military drone doesn't appear to have any gimbal.

[snovv_crash]

41 minutes of spirited flying with hobby components weighing under 250g:

https://youtu.be/u2v1QLmhNxM

[semi-extrinsic]

Nitpick: plural of vortex should be vortices.

It actually appears both spellings are currently accepted in dictionaries, but in the fluid dynamics literature you will essentially only find "vortices", so that's a much better (more searchable) word to use.

[aaron695]

There's no reason to use rechargeables so if non chargeables give them a extra 30% then that would be how they are doing it.

But it will just be off the shelf batteries, so they would exist already on ebay if that's what they are doing.