Optimization of a Coilgun Coil 

Putting the other led into cancel out the back EMF is all you had to do to keep your transistor. Usually we would use a diode or a resistor. An LED is a diode so you're using that energy up which will cushion your transistor.

This was great! Very informative and answered quite a few things I'd been pondering. Cheers!

Probably the most helpful video on solenoid design I have ever watched. ✌

Great video! yes its all about the right balance of your projectile and coil configuration in relation to your power supply with regards to efficiency, other factors such as inductive reactance and hysteresis effect the efficiency as well

Nice video. Been making research on this subject for quite a while (7 months) and this is te best made video i've seen since! This video should have more recognition.

You didn't put a kickback diode for the coil?

Thank you for the informative video, it helped solve a problem in our generator design

Very useful video thanks for the effort you put in this video!

Would love a follow up on this video. Making the wire thickness test to find a practic optimum and test it with the n.o. turns optimum. I was also thinking about if there were any easy ways to lower the resistance in the wire like cooling it etc.

Very interesting! It's been a while since I last played around with this stuff, but iirc one of the considerations for the amount of loops to use is inductance. While magnetic field strength scales linearly with the number of turns, the inductance increases exponentially with the number of turns, which ultimately affects how long it takes for the coil to become (de-)energized. Lower inductance means the coil turns off quicker, allowing you to keep it on for longer. Probably not really a concern for a single stage coilgun, but something to keep in mind for high-speed multi-staged ones, where every millisecond counts :)

Brilliantly done.

I am so happy to see this video. For now we are like a humans who made a first gun within black powder stone bullet and bamboo barrel. But... The age of railgun is coming. I believe.

Sehr cool Paul - kannst du sehr stolz auf dich sein. Liebe Grüße von uns , inkl. Lukas, Lorenz und Lennard :)

Do you have the new schematic with the relay posted? Great job! You answered many of the questions I had about the coil sizes

Awesome video

Great video! Can you make another video with capacitors to discharge the projectile with higher energy?

I just wanted to comment about the inductive voltage spike and that poor Mosfet and LED. Then I saw the poor Mosfets actually died. RIP. (Even though they are avalanche rated: I'm curious if (and by how much) it exceeded the ratings. How high is the current that flows? Do you know the inductance of the coil? If not, what are the number of windings, inner+outer diameter, length?) I also once thought about the best coil design and came to the following conclusions: 1. Number of turns vs thickness cancel each other at same mass of copper and the same power flowing through it. Thicker just means lower voltage with higher current, while thinner requires higher voltage for same power, but less current is flowing. You just need to optimize thickness vs windings for the voltage of the power source that has the best power density (with enough energy for 1 shot). Usually that is 400V electrolytic capacitors. 2. Losses are prop. to I² while field strength is prop. to I. That means double the field needs 4x the power. However, the further out the windings are, the worse they are for field per power. Therefore, for optimal efficiency, outer windings should have thicker wire then inner windings.

If you could make more like this that would be great

Interesting! I am making coilgun for my channel, your video was quite hepfull :)

i have a question. I built a coilgun, from a kit from aliexpress. i built it as it comes but the only thing I did is to put metal washers near the coil to increase the velocity. but every few shots the SCR get destroyed. I thought that it might be problem with the circuit or one of the compouments, but I soldered everything again and check the circuit, I also tried to change the SCR to original ones, but it didnt helped. do you think that the washers that I added cause the problem?

what can you do to stop the back emf? i would like to use mosfets and not relais

What stops the power source from shorting out? I know the magnetic field created consumes some energy and opposes a change in current due to its inductance, and that its only connected for a brief moment. But its still just copper wire? Does the length of it provide enough DC resistance? If so, how much is "enough" to prevent damage? Someone let me know if they know the answer! Ive found a few explanations but i wouldn't say they're exactly related to this question

How powerful can you make it?

why not a flightback diode after the coil?

No resistor is used between the gate and the 12V battery?

But did each of the different coils have roughly the same weight of copper, was each coil just a single layer of copper wire? Or multiple layer? And/or was EACH LAYER wound the same way? Ie starting on left eningd on the right?

why you need relay and mosfet. wasnt it possible without those?

What's the best size for a coilgun's projectile? (For example, .30cal, .45cal, etc.) Hacksmith created a 50cal one but not only was the round too big to move fast, but was also a cylindrical slug that just wobbled. I've heard that a ball shaped projectile would work well, or a(n) (American) football shape would work better..

You can calculate the optimum size without needing to do it in real life

1:25 Before watching this video: the LHS of the equation is maximised when *I* is equal to *n* .

Which one is more efficient rail gun or coil gun?

It would be great if it showed at average speed.

is that enameled copper wire or normal copper wire? What do I use?

U think a microwave transformer hooked up wit coil would worl

Use a capacitor so you can shot it at 500v

Nice one. What about the length of the coil itself, how does that matter?

no capacitor? no invertor or rectifier? a 12 volt DC battery wont give near enough voltage to move that projectile is there soemthing youre not telling us my friend?

Thanks man ... all the youtbers are just making coil guns ,,, you are the one who is actually educating people behind the hands on physics.... thanks brother.... great vedio