Is there a market for large electric ducted fans? Biggest I've

>>1100718
No, i dont need one ,but thanks for the offer.

>>1100718
I would if you market it as /v gaymer shit and stick some razor stickers on it.

>>1100718
What are they for?

>>1100722
I can rice it out yeah
>>1100724
Jet engine imitations on model aircraft

>>1100727
so it doesn't actually do anything?

they better be dirt cheap or i'll just get it from china directly

>>1100729
Nah not really, they just look cool. I guess if you had a big enough one you could make a flying car or some shit idk I just want money.

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>>1100718
if you are serious about it and have the engineering know-how and capital to make one that efficiently produces thrust
electric flight is going to be huge within the next ten years
you probably could start out with a kit that can be retrofitted to sailplanes
and then when the first aircraft manufacturers start developing small motor powered electric planes you can supply them

>>1100739
what do you mean they don't do anything? They power RC planes, that's doing something. However, once you get to a certain size everyone uses actual turbines.

What about making an actual hybrid electric jet engine? I discovered that it is possible recently. Basically you just need an axial 8:1 compressor stage driven by an electric motor, since there's no high temperature turbine spool driving the compressor you don't need the difficult to manufacture high temperature parts.

You still have to make the air intake and outlet chambers but it's simple provided you can buy the compressor stage.

>>1100749
>kit that can be retrofitted to sailplanes

You have until eternity to explain how you plan on packing greater energy density into a complicated turbine motor + battery + interconnect than can be achieved with a single-use chemical propellant motor such as are already in use on certain self-launching sailplanes. I'll wait 30 seconds.

>>1101007
>single-use chemical propellant motor such as are already in use on certain self-launching sailplanes
please show an example, have never seen one only gas turbines, ICE's and electric motors

>greater energy density
you don't need greater energy density, the advantages would be multi use, cheap and easy refueling, less mechanical complexity than turbines or ICE's and much lower noise

>>1101007
>You have until eternity to explain how you plan on packing greater energy density into a complicated turbine motor + battery + interconnect than can be achieved with a single-use chemical propellant motor such as are already in use on certain self-launching sailplanes. I'll wait 30 seconds.
If someone makes an electric jet engine you can make high speed aircraft without the gas turbine expenses. Because electric engines weigh very little you can have different engines for different speeds, a large ducted fan for low speed and the jet engine for over 600km/h.

Supersonic RC planes should be possible.

>>1101026
what do you mean by electric jet engine and in what way would it be different than a ducted fan

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>>1101032
Turbojets don't quite work how people assume they do, all they need is to do is compress air then send it into a chamber where it is heated, traditionally burning fuel which spins turbines to drive the compressor was the easiest way. But there's no real need for that component, the air can be heated by exploiting it being propelled to supersonic speeds, heating elements or plasma arcs. In this image the air is heated by exiting the compressor through a small hole which accelerates it to mach 1+, due to friction and colliding with the chamber walls it is rapidly heated creating large amounts of pressure from heat expansion. As it cannot flow back into the compressor stage it exits the final nozzle at mach 1+

Jet engines are very much like conventional engines and how torque x rpm = power. Instead thrust devices are thrust force x velocity of the aircraft. So with an electric motor 50nm x 1000 rpm is less powerful than 5nm x 20,000 rpm, however if you were to put both on a direct drive electric bike the 5nm motor will be very sluggish. With ground vehicles you can just add gearing.

Aircraft don't have the same luxury, the pitch of props or ducted fans can be altered at lower speeds but their top speed is limited by the them not working if the blades rotate at supersonic speeds, there's just no way for them to hurl air faster than 500-900km/h, once they reach maximum speed thrust becomes 0 and power output = 0 even if you're consuming lots of energy.

Now a turbojet produces a lousy amount of thrust but does so at very high speeds, so once your plane is travelling above 700km/h or so the turbojet is suddenly more efficient than the prop or ducted fan. As a result the turbo jet is now outputting more power. While the it still has the same weak thrust it can gradually accelerate the vehicle to well above mach 1. I'm unsure what the efficiency of an electric turbojet would be, conventional ones are 40% or so provided you travel at high speeds.

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>>1101093
An interesting thing is the concorde turbojet engines are more efficient than modern airliners when it is traveling at mach 2, however flying at lower speeds still consumes less energy overall even if the conversion ratio is inferior.

Non-combustion turbojets have been around for a long time, they built nuclear ones in the 1960s. All they do is heat the air enough to spin the compressor turbine. Since there was no easy way to store high densities of electric energy for decades nothing more was done about it. Now modern lithium batteries are likely good enough to do it. Airliners are still better off with conventional engines as lithium battery energy density is still lower and they can afford to spend millions of dollars per engine.

For hobbyists and light aircraft electric ones may already be viable due to the ease of construction and being easy to maintain. If battery energy density ever matches fuels you will likely see large electric jets.

>>1101099
OP here
Interesting I didn't know about this. So you're saying it's theoretically possible to swap out a turbojet combustion chamber with an electrical heating element? This is cleaner but it won't be much simpler because the main complication of a turbojet is the turbine that catches the hot air.

>>1101152
>Interesting I didn't know about this. So you're saying it's theoretically possible to swap out a turbojet combustion chamber with an electrical heating element? This is cleaner but it won't be much simpler because the main complication of a turbojet is the turbine that catches the hot air.
You remove the turbine altogether and have an electric motor driving the compressor stage. In a traditional jet engine you burn the fuel largely for the sake of spinning the turbine which powers the compressor. But gas turbines operate at less than 40% efficiency, a dc motor driving the compressor would be 90%+ so if you're running on batteries there's no reason to use heat to drive the compressor.

With the turbine out of the way you no longer have to build the high temperature turbine blades and bearings. The compressor side only reaches 200-300C. You may not even need the heat element, I have seen proposed designs without them using expansion chambers to superheat the air, you would have to test heating vs more compressor power. See my crap drawing above the nuke jet to see the basic layout. You could also include some fuel and have afterburners for short bursts of high thrust for take off and high speed runs but use electric drive for efficient cruising.

>>1101202
If you aren't heating the compressed air I don't think there's any point in this because you won't get out any more power than the electric motor can put in i.e you may as well just attach it to a fan.

Maybe a hybrid design? Electric power to run the compressor + fuel powered combustion chamber.
>But gas turbines operate at less than 40% efficiency
That's the whole cycle not just the turbine. This hybrid system would still be subject to the same thermodynamic cycle therefore the efficiency from the fuel section will still be 40%

I don't think this is a good idea, by adding compressors and combustion chambers you've now lost the simplicity of the electric ducted fan yet still have a worse power source. Also compressors suck on the small scale which is the market here.

>>1101211
>If you aren't heating the compressed air I don't think there's any point in this because you won't get out any more power than the electric motor can put in i.e you may as well just attach it to a fan.
No you're missing the point, a ducted fan or prop will hit it's top speed at 600-800 km/h if you want to go faster bigger props, faster or more powerful motors won't do anything they physically cannot propel the air to higher speeds.

A turbojet electric or combustion compresses and heats the air via the compressor then using heat expansion and chambers accelerates the air to supersonic speeds. The combustion stage is optional and largely exists to drive the compressor. If you input 400A @ 36V on a ducted fan to reach 600km/h but the electric turbojet can travel at 1200km/h with the same input it is far more efficient.

The afterburner option is also interesting, it takes place where there's no moving parts so cost is minimal, because you didn't burn the oxygen in the air to begin with you're left with very hot dense oxygen rich air, throw some fuel in and you have a high powered rocket engine for take off and accelerating to cruise speed.
Alternatively the afterburner can be omitted and conventional props or fans can be used for low speed flight to reach minimum speed at which point the jet intake ramp and compressor can heat the air well enough.

I still think hobbyists would eat up an after burning electric turbojet, they would still get all the same jet engine sounds and flames but without the $5000+ cost and trouble of maintaining the engine. It would cost more than an edf because you would need 4 or 5 fans + stators but you escape the costly traditional micro turbine parts, dealing with the 100,000RPM radial single stage is difficult and then building the turbines + bearings out of something that can operate at 1000c+, additionally the compressor is connected by a metal rod to the turbines so heat travels to the compressor.

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>>1100749
>electric flight is going to be huge within the next ten years
>ten years

Ha ha, no. Unless there's some major, sudden breakthrough in battery technology, that one's pretty far off, still. Weight is paramount in all aspects of aviation, and batteries just weigh too much for a given amount of energy storage. Cars (and, to an extent, boats) can handle the weight penalty in exchange for some additional overall efficiency. Planes are going to be stuck with hydrocarbons for quite a while, even if there are a few very niche applications for electric thrust, currently.

>>1101007
Supercapacitor tech is nearing maturity.
Fast charging, fast discharging, the only thing left to work on is total energy capacity. Conventionally you can only have two of the three, once supercaps are mature, we'll have all three.

So guys should I build this 400 mm EDF or what?

>>1102553
Do it, it will make great vtol drones. Could you consider a twin motor version with stator and contra rotating blades?

Have a look at the F-35 liftfan for example, instead of gearing just have 2 electric motors, if you make it modular most of the parts should be shared between single and twin versions.

>>1102663
Sure that can come as a later upgrade. When it's done how do I advertise it? Kickstarter?

>>1100718
If you can make it silent, long life, and somewhat cheap then there's a huge market in the pot growing industry for you.

>>1102878
>Sure that can come as a later upgrade. When it's done how do I advertise it? Kickstarter?
See who offers the best deal, there's kickstarter, crowdsupply and indigogo these days. I think crowdsupply might handle shipping logistics not sure about the other two.

Do you have any idea what materials you would use and cost etc?

>>1100718
>Is there a market for large electric ducted fans?
Yes, electric industrial fans are a thing.
>if I was selling 300 mm, would you buy it?
Not unless I came up with a use.

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>>1100749
>efficiently produces thrust
>ducted fans

>>1103077
Plastic. with the motor and manufacturing costs, ballpark estimates of £280 so if I did sell it it would have to go for around £500. This is cheaper than Schubeler ducted fans (£1,000-3,000) and Jetcat turbojets (£2,000-3,000) for the predicted thrust you get.
Thanks for your input /diy/ I'm gonna go work on it now.

electric superchargers for cars?

>>1103232
Snake oil.

>>1103255
They do work, I've measured power increases on the dyno. This is objective fact.

>>1103272
Post it then, faggot

>>1103272
They're bullshit, they don't work.

>>1102663
Hey I've been thinking your suggestion for a contra-rotating version is a really good idea. AFAIK no contra-rotating EDFs exist on the market and an F-35 RC copy would make a great high speed yet VTOL drone (if it's possible). I will definitely work on that if the single fan version is successful and popular.

This will be the product line everyone
- 5kW 360 mm single fan (for RC jet, jet bike, whatever. CW and CCW versions available if anyone wants to make a multirotor)
- 10kW 360 mm contra-rotating double fan (for VTOL drones)
If anyone has any more suggestions please do post.