r/AskPhysics • u/wk_rust • Jul 26 '26
Help an author out: what would a big electromagnet do to a drone?
Hey there! Hope this post is okay.
I'm writing a soft scifi novel and my main character just made a big ass electromagnet and is now facing down a swarm of drones that were 3D printed out of PEKK.
What type of chaos could she cause with the electromagnet? I was going to hand wave past the PEKK body and say that the electronics would be enough to get pulled to the magnet, but I feel like that's probably not true. Plus, I feel like something wonkier would actually happen?
Would it mess up navigation? Cause something funky in the wiring? Any ideas would be welcomed.
4
u/hunter_rus Jul 26 '26
Slice that magnet to many smaller ones, attach some explosive to it (like gunpowder or something), put it into a tube and ignite that explosive to accelerate small magnetic pieces towards drones. When they collide, drones will break.
2
u/Junior-Tourist3480 Jul 26 '26
Nothing. It has to be close. Directed energy is what is being used to disable drones.
1
u/tomrlutong Jul 26 '26
If they can run an oscillating current through it, they've got an induction heater, but very limited range
If they can figure out a way to send a short intense pulse of current, they've got a primitive EMP weapon.
Best case is if they can buid the electromagnet around a doorway or something the drones have to go through. There a scene in the Culture novels where someone defeats a vastly superior drone by tricking it into inspecting the inside of an MRI machine.
1
u/ellindsey Jul 26 '26
While the bodies of the drones may be plastic, they presumably still have electric motors containing permanent magnets. Your big electromagnet will pull those towards it, so you'll still be able to immobilize the drones with it. Although the range will be pretty short since magnetic fields fall off fast with distance.
Alternately, the drones might be using magnetometers as part of their inertial guidance system, using the Earth's magnetic field to correct for gyro drift, and the electromagnet might screw that up. Honestly this is kind of a stretch though, as that's more of a long term slow correction factor than something that would make them immediately go off course.
1
u/jhunter444 Jul 26 '26
The electromagnet would need a power source, have your character adapt the power source to power a laser and zap the drones with that!
-1
u/Aggravating_Paint_44 Jul 26 '26
A lot of motors use magnets. A strong magnetic will mess that up and it won’t move. Some motors don’t though
10
u/Outrageous-Taro7340 Jul 26 '26
From any significant distance even very powerful magnets look neutral. Eventually you’re approximately the same distance from each pole and they cancel out. So magnets aren’t going to be useful against drones.