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I am designing a human society that exists in the near future. After the development of mass-produced, relatively cheap lithium-sulfur batteries (superior energy density to lithium-ion), electric vehicles- particularly aircraft- become much easier to engineer, as batteries are not nearly as heavy and can carry a longer charge.

As the society exists in extremely difficult terrain, the military funds the development of low-cost, battery-powered helicopters. These two- or four-seater helicopters have decent range (350 miles or so), and are small, light, and (relatively) simple to operate and maintain, and cost less than (the modern equivalent of) $70,000 apiece. They are primarily used as a cheap and easy method of transportation or for reconnaissance, being too small for heavy weapons. They are quite common and (ideally) intuitive to fly, even to one with minimal flight experience, so much so that a streamlined mainstream model becomes quite popular with civilians living in undeveloped areas.

This article makes it seem like electric helicopters are potentially feasible, even with lithium-ion batteries. However, my understanding of helicopters is that they are not easy to fly and are usually quite expensive due to complex mechanics. This helicopter, which seems similar to what I'm shooting for, costs over six times what I'd like mine to.

Are cheap, dime-a-dozen electric helicopters possible to manufacture?

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    $\begingroup$ Several companies are developing electric quad-copter-like person-carrying flying machines, and at least a couple are already on the market (albeit not cheap). A conventional rotor helicopter is more efficient, albeit less amenable to computer control (though a quad-copter is literally impossible for human reflexes to stabilize without computer assistance). $\endgroup$
    – Zeiss Ikon
    Nov 1, 2022 at 15:58
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    $\begingroup$ Unrelated but an interesting side note: zip lines and other "Tyrolean Traverses" have been in used for literally thousands of years in very difficult terrain. en.m.wikipedia.org/wiki/Zip_line I would expect this (along with elevators) to be common for citizenry in the area, but it would pose a problem for helicopters. If the blades hit a line, it's bad news for everyone involved. Not to mention it's much cheaper to string a steel cable for any standing infrastructure. $\endgroup$
    – PipperChip
    Nov 1, 2022 at 16:50
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    $\begingroup$ @bukwyrm They could live with fixed-pitch; this vehicle is purely designed for cheapness/simplicity above all else. I was thinking of taking a transverse approach with two fixed-pitch rotors (like in Avatar), but I’m not sure that’s the same since transverse rotors are also highly complex. $\endgroup$
    – Mark Price
    Nov 2, 2022 at 16:25
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    $\begingroup$ @Negdo the helicopters are designed for moving people, basically like a flying Jeep. A drone could work as long as it can still carry 2-4 people, but I assumed if people would be in the thing anyway they could drive it too. $\endgroup$
    – Mark Price
    Nov 2, 2022 at 16:25
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    $\begingroup$ Define "near future". Tomorrow, no. Next year, doubt it. 100 years from now, maybe. $\endgroup$
    – MonkeyZeus
    Nov 2, 2022 at 18:30

9 Answers 9

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Microlite Aircraft

enter image description here

Microlite aircrafts are the sort of things that Father and Son teams build and repair in their garage on weekends and then fly over the farmsteads of Cornwall. Weather permitting of course.

Microlites are not helicopters. But it does not seem important for your question that the cheap small electric aircraft is a helicopter. Certainly a fixed wing machine is easier to fly than a spinner.

The microlite uses gasoline for fuel and weighs about 100kg. For reference that's about 0.85 Dwayne Johnsons. In the US a microlite can have a fuel tank at most 20kg big. The battery is about one quarter as weight-efficient as the fuel. Wikipedia says the batteries have a theoretical efficiency of about 2500 Wh/kg compared to about 12,000 for gasoline. If you replace one of the two passengers with an 80kg battey you might get the same amount of power in a one-passenger electric aircraft as a two-seater gasoline aircraft.

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    $\begingroup$ Worth noting that in the USA, a Part 103 Ultralight (equivalent to your microlight category) is also limited to a single seat and has a level flight top speed limit. $\endgroup$
    – Zeiss Ikon
    Nov 1, 2022 at 15:55
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    $\begingroup$ @ZeissIkon Sure, but those are regulatory limits, not engineering ones. It's not that you couldn't build an ultralight with two seats and a high top speed, but they'd make you get a pilot's license to fly it. $\endgroup$
    – Cadence
    Nov 1, 2022 at 15:59
  • $\begingroup$ And in the USA, they call that a "light sport" airplane, or whatever name that class wound up with -- the license has restrictions on aircraft weight and passenger carrying, as a tradeoff for requiring a fraction of the instruction to qualify. $\endgroup$
    – Zeiss Ikon
    Nov 1, 2022 at 16:02
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    $\begingroup$ "the society exists in extremely difficult terrain" – it might be difficult to have runways long enough for a non-VTOL air vehicle. $\endgroup$ Nov 1, 2022 at 23:40
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    $\begingroup$ @PaŭloEbermann Some of these things can take off an land in a few dozen metres. $\endgroup$
    – Daron
    Nov 2, 2022 at 10:22
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No

Your battery technology only does one thing to current helicopter designs: it replaces the motor and fuel tank of today's helicopters. All other aspects of the helicopter remain the same and cost the same.1

We can look at what helicopter engines cost today and see that they're about \$375,000. The helicopter you link to in your post has a price tag of about \$450,000. That means everything else costs \$75,000, which is already more than the cost you want.

The electric motor and batteries just add to that cost. And no matter how inexpensive the batteries are, the cost of the motor will always be substantial.

However, how far into the future are we looking? Today's technology becomes cheaper over time, so it's not impossible, eventually.

But, today... no. You'll be hard pressed to get the helicopters into the \$150k-\$250k price range.

But does any of that matter?

Today people look forward to electric vehicles with a lot of hope. So much that they don't even bother to look behind the curtain of their local electric car charging station and see the diesel generators lurking there.

In short, I believe people will find your idea plausible, and therefore suspend their disbelief to continue with the story.

I don't think it's worth asking whether or not what you're trying to do "can" be achieved at the cost you want. Who cares? I love the idea and hope you'll stop worrying about whether or not it's possible to really build one right now and move on with your story.


1This isn't entirely true. The combustion engine and fuel tank will be heavier and take more space than the electric version will. That means the helicopter as a whole can be built smaller and more cheaply vs. its combustion counterpart while carrying the same load. However, I do not believe that will reduce the price enough to materially change my answer.

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    $\begingroup$ Economies of scale can also drive down the cost. $\endgroup$ Nov 1, 2022 at 23:44
  • $\begingroup$ @PaŭloEbermann Economy of scale doesn't drive down the cost. Demand drives increased production and then economy of scale brings lower prices. But in the long run, I think that part of the question is an unnecessary debate. It wouldn't be a challenge to come up with a series of invented events that result in (e.g.) economy of scale. That's just window dressing for a story where the OP decides what the cost for his/her helicopters are. $\endgroup$
    – JBH
    Nov 1, 2022 at 23:49
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    $\begingroup$ On the controls issue - would be interesting to see how practical it would be to replace the very-difficult-to-master cyclic+collective+pedals+throttle combination with simplified computer-assisted controls. (P23-29 of Chickenhawk by Robert Mason gives a great description of how hard they are to learn.) Strongly suspect that computer assistance for ease of learning would reduce the pilot's options in some situations. Agree with everything re production costs +1 $\endgroup$ Nov 2, 2022 at 1:36
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    $\begingroup$ Electric motors will do away with a huge amount of highly-stressed mechanical stuff in a helicopter. Direct drive to the rotors and computer control of motor speeds. As we see with quad-copter drones. However, weight and range are a fundamental problem for batteries. Enter large numbers of fast-charge helipads? $\endgroup$
    – nigel222
    Nov 2, 2022 at 9:59
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    $\begingroup$ You can get a single seat gasoline "helicopter" for ~35.000€: The SCH-2A, though it does come with a few tradeoffs... Wind in your hair is one of them. $\endgroup$
    – predi
    Nov 2, 2022 at 11:30
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Drones/Quadcopters not Helicopters

H

They are smaller and more intuitive to fly. They can be partially or fully automated. They have fewer moving parts making them easier to maintain.

A 3d carbon fibre body could be printed where the cost could be reduced to that point.

If you look at electric cars, you have four electric motors, battery system, electronic control system, battery and a carbon fibre body all around that price range. If today's batteries were smaller and motors were more efficient, you could mass produce quadcopters exactly the same way.

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    $\begingroup$ @PaŭloEbermann a drone is an unpiloted vehicle of any type. A "quadcopter" is one type of vehicle. One can have piloted and unpiloted quadcopters. An unpiloted quadcopter is appropriated described as a drone. However, more to the point, Thorne... A drone removes the pilot's weight and carbon fiber tech can be applied to any vehicle. How does your post answer the OP's question(s)? $\endgroup$
    – JBH
    Nov 1, 2022 at 23:52
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    $\begingroup$ A quadcopter/drone is mechanically far simpler than a helicopter. It's can be semi/fully automated making it easy to fly. Has less moving parts so is easier to maintain. $\endgroup$
    – Thorne
    Nov 2, 2022 at 0:11
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    $\begingroup$ you may want to look at something like the eVTOL, many are essentially a piloted electric quadcopter. several are already in use. drone is just confusing terminology. with a little fleshing out this could be a great answer. $\endgroup$
    – John
    Nov 2, 2022 at 0:16
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    $\begingroup$ @Thorne and they can't autorotate, so any failure in one of the four motors would lead to a crash. This is not a huge problem with today's small hobby drones only carrying a camera, but imagine millions of them over a city in the rush hour, carrying people. $\endgroup$
    – vsz
    Nov 2, 2022 at 7:20
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    $\begingroup$ Hexacopters are tolerant of one or two motor failures. Octacopters are even more failure tolerant. $\endgroup$
    – Monty Wild
    Nov 2, 2022 at 8:44
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Electric helicopters won't be cheap any time soon, even with lithium-sulfur battery technology.

We've been able to build practical electric cars (at least for city use) for more than a century, but the ones with enough range and performance to get out of a city or travel between cities currently cost about twice what an economy model gasoline powered car of similar specs (passenger/load capacity, acceleration, and range) does -- and as technology is continually added, even gasoline powered cars are headed for price ranges where they won't be universally affordable.

Given the much higher minimum power requirement for a helicopter to remain aloft vs. a car traveling on a highway, plus the need to lift a heavy battery, endurance and performance will tend to be poor compared to fuel powered aircraft. Current quad-copter type electric aircraft have a flight duration of less than an hour (much less, in some cases). A conventional rotor layout would help (fixed wing even more so), but even an electric version of a Cessna 152 isn't yet a practical reality.

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  • $\begingroup$ Bad analysis. Today 50% of EV costs are due to it being electric, with 25% on just the battery cell alone. statista.com/statistics/940722/bev-manufacturing-cost-by-type This is a price that is going to drop immensely. Same for engine and engine-electronics. These are parts with a ridiculous fraction of the engineering that combustion engines have enjoyed. Their prices (or price per performance) is going to drop rapidly as the field develops. OP is not talking about having it in 2024, your analysis is $\endgroup$
    – Hobbamok
    Nov 3, 2022 at 15:34
  • $\begingroup$ @Hobbamok Or maybe battery prices won't drop as predicted. I don't see combustion engines costing a lot less (in real money) than they did in, say, 1970, in fact they cost more -- they also burn less fuel and pollute less, but they certainly don't cost the end user less, and the rest of the car has virtually doubled in cost in real money over that time. $\endgroup$
    – Zeiss Ikon
    Nov 3, 2022 at 16:18
  • $\begingroup$ 1970s combustion engines are the Nokia 3110's of combustion engines. You are saying that phones got more expensive because an Iphone 16 costs more than your Nokia 3110. They are barely in the same class. And you don't buy "one battery in this car please" but you combine a ton of cells together, something that engines can't do. And guess what cell prices per kwh are doing quite rapidly. Falling. And that is without OPs given Lithium-Sulphur, which will do to battery prices what gasoline engines did to combustion engines in general (= wood or coal fired steam engines) when it came around. $\endgroup$
    – Hobbamok
    Nov 3, 2022 at 16:29
  • $\begingroup$ But sure, maaaaaybe prices don't drop for some reason. But OP isn't asking for a future analysis for the purpose of investing or so. They asked for general fictional feasability, which means we can assume good or neutral conditions. And also: no, the rest of the car has NOT doubled in cost. There is just more stuff in a car nowadays. Stop looking at Iphone16's, stop looking at BMWs latest car . We (me & OP) are talking about Lada Nivas here. And their prices are historically declining significantly. $\endgroup$
    – Hobbamok
    Nov 3, 2022 at 16:32
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Flocking drones.

drone flock lifts truck

https://www.youtube.com/watch?v=hkysTzikBBU

Pretty sweet ad!

Let us consider small cheap drones, because I too am small and cheap. Let us consider a 100 USD dollar civilian drone that can lift 0.5 kg. I weigh 100 kg in the buff. It will thus take 200 drones to lift me. That is 20,000 worth of drone. We will add another 100 drones because my drone harness is heavy (that is real gold) and I will want to bring snacks. 30,000. That is half of what you ask for a helicopter in (inflated future dollars!) and the flocking drones are better.

  1. Redundant: if one malfunctions you don't fall from the sky.

  2. Redundant: if some are in the shop you can deploy your spares and keep on flying.

  3. Flexible - I might send only part of my fleet to carry my cat from place to place, or add some drones for hire when the flock carries me home from the barbeque place.

  4. Cheap. We started with cheap, and small.

The trick here is the flocking software. Flocking drones are not new or futuristic.

drone swarm at olympics

https://dronebelow.com/2018/02/10/record-breaking-intel-drone-swarm-lights-pyeongchang-olympic-winter-games-2018/

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The main reason helicopters are expensive is safety standards (redundant systems, parts that don't have mechanical failures, all kinds of sensors for avoiding things like mid-air collisions, communication and navigation systems, etc).

If you don't mind catching on fire before plummeting to your death you could probably produce small helicopters for less than $10000.

For a fictional military, "cheap and unsafe" helicopters is very plausible (why spend $$ when you're probably going to be shot down anyway?).

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Ignoring any issues with the lithium sulfur batteries (powerful batteries can be difficult to develop and produce, but the question seems to indicate this is a non-issue in your world), I don't see why not. A sophisticated computer system on your helicopters can make flying accessible to everyone, or even fully automatic. We have drones, and what's a helicopter if not a really big drone?

Adding an advanced computer system, however, is going to drive the price up. Luckily, however, you stated that the military funds the development of these helicopters. Government subsidies can help keep the price down (if they want everyone to use these helicopters, they'll be eager to promote their usage).

I'm sure there are other issues which make these helicopters less viable in our world, but none of them are major enough that you can't hand-wave them away with "computers" or "money" or something along those lines.

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    $\begingroup$ I expect that there's more than enough raw compute power in any gamer's PC. Drones can be controlled by a Raspberry Pi! The issue is software. It has a high development cost but zero reproduction cost. So once it's been developed, the price can progressively fall. Initially, it will be sold at high cost to the highest bidder (the military). Once they have bought all they want, the price will be dropped to catch other markets. And then, the competition will arrive and the price will be driven right down. $\endgroup$
    – nigel222
    Nov 2, 2022 at 9:51
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Yes.

More specifically, a low-performing version could become substantially cheaper than today's helicopters or today's electric cars. (A low-performing, much cheaper version of electric cars should also be possible.)

The technology — and hence the complexity — of electric transportation is much simpler than with combustion engines. You can get an idea if you look at the development of model drones; 40 years ago, they were basically James Bond issue, expensive cutting-edge technology unaffordable for the general public. Today you find them in blister packaging hanging by the supermarket cash register, and they run until you crash them without any maintenance. Batteries, circuits, electric motors and the plastic body are that simple and cheap.

There is, however, a floor to the price of large items simply because of the amount of energy and material needed to produce them; an electric car will always cost more than an electric bike. But with cheap batteries there is no reason why a "google bubble car" or a corresponding "bubble quadcopter" should be much more expensive than half a ton of plastic, 200 kg of Lithium and a kilometer of copper wire. Because of the mechanical and power limitations you won't be able to perform aerial acrobatics or fly races with it, but they'll get you from A to B in a rather boring fashion, just like a google bubble car.

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Assuming that they are mass produced, the best option is quad copters or some type of ring around the propellers otherwise there would be a high risk flying on of these as you are not constantly looking up when flying. One wing broken means that you have to get out. There is also a potential danger when the helicopter falls to the ground.

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