Looking at the beatiful show, I cannot avoid thinking: “each of them a potential weapon”.

So in fair weather, when communication is smooth and all navigation systems are working, it’s entirely feasible to coordinate a swarm of 10 000. Wow. :)

Soon enough, they will be coordinating each other in the presence of electronic warfare, and swarms of 100+ fly already, so 1000 is the next step. Anyone doing air defense is probably designing energy weapons (lasers, masers, etc) at a pace approaching madness, besides making ever-cheaper drones.

As for the environmental footprint - if each drone withstands 10 performances, they will probably save resources. :)

Relays: my use for truck relays is switching on heaters in my thermal storage water tank. Not big ones, though - I use relays rated for 24V and 40A of current. Since they are old, I have applied a safety margin and only let 25 A flow through them, so each of them handles 24 x 25 = 600 W.

As for using DC appliances: benefits do exist. If a household has a low voltage DC battery bank (some do, some don’t) then dropping the battery voltage a few times to power car parts comes with a smaller efficiency loss. In my household, DC appliances are used for lighting, communications, computing, cooling food, pumping water and soldering electronics. The rest goes via AC. I think a car air conditioner could cool some small storage room decently. With big living rooms, it would have difficulty since it’s a small device.

Relays can be used for anything, and a car contains a fair number.

You can make a pulse jet engine from a muffler parts, but a solarpunk society would probably not do that. :)

Copper brake pipe and cooling radiators can be used as heat exchangers for other stuff.

Air conditioner parts can be reverse-used for Stirling engines or to pump heat in other contexts.

Thanks for the news, but also - thanks for posting a proper summary. :)

(So many videos have only the YouTube-compiled summary, which is typically totally off topic.)

Nice to hear. :) The process seems doable in a suitably equipped factory. :)

The transfer to electricity could be done by using the heated mass to heat a hot pumped liquid or using transfer rods made of a solid material with a high heat transfer coefficient.

Alternatively, heat can be extracted by pumping liquid metal (sodium, tin, low-temperature eutectic alloys) in a pipework of copper (if there is chemical compatibility with copper). But handling liquid metal with a magnetic pump isn’t typically done on the DIY tech level.

To be honest, I tried a fair number of experiments on the subject, including low-temperature Stirling motors. They’re difficult to build well. I would recommend plain old steam turbine. Steam means pressure, pressure means precautions (risk of bursting, risk of getting burned), but modern approaches to boilers try to minimize the amount of water in the system, so it couldn’t flash to steam and explode.

I have superficially researched both options (with the conclusion that I cannot use either, since my installation would be too small, and would suffer from severe heat loss due to an unfavourable volume-to-surface ratio - it makes sense to design thermal stores for a city or neighbourhood, not a household).

I’d add a few notes:

1. A thermal store using silicate sand is not limited by the melting point of the sand, but the structural strength of the materials holding the sand. You can count on stainless steel up to approximately 600 C, more if you design with reserve strength and good understanding of thermal expansion/contraction. Definitely don’t count on anything above 1000 C or forget the word “cheap”. I have read about some folks designing a super-hot thermal store, but they plan to heat graphite (self-supporting solid material) in an inert gas environment.

2. Heat loss intensifies with higher temperatures, and the primary type of heat loss becomes radiative loss. Basically, stuff starts glowing. For example, the thermal conductivity of stone wool can be 0.04 W / mK at 10 C, and 0.18 W / mK at 600 C.

3. Water can be kept liquid beyond 100 C. The most recent thermal stores in Finland are about 100 meters below surface, where the pressure of the liquid column allows heating water to 140 C.

4. However, any plan of co-generation (making some electricity while extracting the stored heat) requires solid materials and high temperatures.

I played the idea a few years back, at some anarchist-leaning not-just-music festival. We tried setting up a link over a 70 m hill, both stations using 433 MHz (500 mW transmit power, quarter wave antennas) narrowband (no frequency hopping) LoRa boards from Chengdu EByte. Stick antennas, not directional. Both stations were right below the hillside, so the hill formed a perfect obstacle between them.

Communicating over the hill in a single hop proved impossible. With a repeater at the hilltop, it was possible to make contact with the repeater from street level (no line of sight, trees obstructing), but the repeater (Meshtastic didn’t exist back then, it was entirely homebrew) had software bugs, so - no link to the other hillside. :)

With better software and better planning, the experiment would have succeeded. :) And if we’d have tried building a link over a valley, it would have been considerably easier.

With ordinary WiFi and directional antennas (panel or ladder antennas), I’ve been able to establish links over 1 km. If one used a LoRa card, and had a directional antenna for the frequency involved, in clear line of sight, I believe 10 km would be attainable without being a radio specialist.

It looks beautiful, but a bit fragile - I’m not used to seeing wooden wings and a jet turbine. :)

I would feel more confident with a propeller-electric rebuild of Antonov An-2 “crop duster”. Which sadly doesn’t exist. :( Someone has to do it, or do a similar thing. :)

If the approximate weight of an 18650 cell is 50 grams, 8000 of them would indeed be 400 kg. Probably more, since they must be packaged somehow. But the pack can be split into modules which a one person can haul around somehow.

Myself, I went for 45 km/h officially (unoffially, on a flat road, I could reach 53 km/h). While turning, for safety reasons, I limited myself to far lower speeds (25 km/h).

Designing a car suspension system for reasonably high speed seems hard, I have never tried, instead choosing the robust and crude solutions to get a reasonable assurance of strength.

Motorcycles seem easier. Especially since most of factory-made motorcycles use a sprocket and chain - a very flexible system for dropping in other power sources. I imagine that with enough know-how to get through type certification, a lot of combustion bikes could become e-bikes with excellent riding characteristics. :)

Yep. I’ve done an L2e, and some day I will manage an L7e. :)

Interference testing was not needed. The motor wattage and motor controller wattage labels were examined. I could have dropped in more power in a mood for forgery, but I was in an honest mood. :)

What I see on his photos are at least 2 (third one likely in reverse, where his finger is pointing) reasonably powerful electric motors on a single toothed belt pair of toothed belts.

image

I think there’s no combustion engine left in that car. I suspect he combined them because the van wouldn’t ride well with only 10 KW.

I would have loved to have / build something like this but in my well regulated european country it’s near impossible to get this street legal certification.

Yep. :( The certification manual here, in a moderately regulated European country, is about 250 pages long. Fortunately, not all chapters apply to moped-cars. If one really really wants, moped-cars are the way to break through the barrier.

It seems like he used the engines of electric “raiders” (ride-on lawnmowers, that is - small tractors). I cannot fathom why and how he used 3, but the tools in his shed suggest he can build anything. That’s one impressive shed.

You’re correct. Only the roof is likely to give significant power. Been there and done that, on the opposite side of the planet though. :)

The “something” on the picture I attach… was built in some squat in Eastern Europe. It had a flat roof of approximately 2 x 1.5 m, all of it solar panel. Solar panels weren’t great back then. Typically it charged its 4 KWh battery in a few days of sunshine. Only during midsummer (18-hour days) was there any chance of a full charge in a single day.

Unlike the van, the “something” required a smaller inventory of tools to build. Instead of lawnmower motors, a Chinese electric motorcycle motor was used. Sadly it’s now retired due to metal fatigue. :( Lesson: never build a structure that flexes out of aluminum - aluminum has no fatigue limit, any flexing will lead to cracking.

Nice stuff, sadly - not for my latitude. Most likely I couldn’t keep these critters alive beyond October, and would have trouble restarting the culture until May. Maybe with heavy thermal insulation and the vermiculture filter somewhat underground… but then again, sometimes when the snow melts, everything that’s underground and is not sealed, gets flooded.

During the Little Ice Age, cabbage and kale were among the plants that kept farming from collapse (they don’t fail like the ordinary crops when snow arrives in summer)…

…so dinner almost certainly did include something of the sort. :)

Depends on the person - I have seen households where a person uses less than 20 liters per day. :)

Besides, seawater can be used to wash oneself or flush a toilet - I think it’s the use of drinking water that makes a difference.

Wow, interesting. :)

I tried getting something like this a while ago.

I wrote a Java program that would use an USB serial adapter on Linux to talk to a radio modem (I tried a few varieties, mainly RFDesign and Chengdu EByte) and broadcast text messges. The program was roughly subdivided into a backend (repeater, this could be a Raspberry Pi) which didn’t care about message content, and a front-end (user interface) which tried to decrypt every message, enabling messages without any recipient or sender ID.

The cipher was a one-time pad, and the clue to decryption was the unencrypted “pad index” field telling which index to take key material from (the program would take it from all of one’s pads and try sequentially). If the message did decrypt, a checksum was revealed which matched the rest of the message, and this is how the program told the difference between success (show in the UI) and failure (discard, republish for others, don’t retry decryption).

I also demonstrated (poorly) use to comrades in Finland during one Musta Pispala festival, but we didn’t get far at all - buggy software and under-performing hardware are hard to demonstrate. But I did learn a lot and might retry some day. :)