{{tag>hardware build weapon}}
====== HCR Repulsor ======

The HCR Repulsor is what I'm calling my attempt to build a hybrid coil rail gun. 

HCR - Hybrid Coil Rail

Repulsor - Because the magnetic field is repelling the projectile, rather than pulling it.

===== Hypothesis =====

Because traditional coil gun design is an open-air coil / sliding core, it is highly inefficient. If one could utilize a iron-core electromagnet in the generation of the magnetic field, efficiency could be drastically improved. My hypothesis is using an iron-core electromagnet paired with a non-ferromagnetic slug which has a magnetic field around it due to a large current passing through it will be more efficient than an open air coil pulling on ferromagnetic slug.

This repulsion-based design side steps several issues with tradition coil gun design:

  * Where to position the projectile relative to the coil (this ties into the below problem)
  * Timing issues with the capacitors being fully drained before the slug gets to the middle of the coil
  * No drag due to the (now magnetized) slug passing through the coil

Note: being the uneducated plebeian that I am, I have not actually done the physics/engineering calculations on this and could be very very wrong. I'm still trying to learn how to translate magnetic field strength (gauss/tesla) into force (newtons). 

===== Update ======

I have evidence showing that a magnetic field around the rail gun absolutely improves efficiency. This can be from permanent magnets or from coils. This changes my design a tad, but increases the likelihood of functioning. 


===== Next Steps ====

I think the ultimate design will be rails and electromagnets--Neodymium magnets *might* be strong enough on their own, but I think a good coils design will prove much more powerful (and much cooler to look at and build).

==== Step 1: Bench Top POC ====

I need to prove for myself that the basic design works. I've been (for years now) getting caught up on making rails that will last a long time and be extremely functional--this has been stalling progress on this project. The benchtop model will be just good enough to work. It will use cheap steel for the rails, permanent magnets, and a benchtop PSU.

=== Tasks  ===
  - [[http://www.instructables.com/id/Convert-A-Computer-Power-supply-to-a-Bench-Top-Lab|Build a benchtop PSU]] (from a computer PSU)
    * Need old PSU, resistors, heatshrink tubing, terminals, LEDs, cool switch -- most should already be kicking around


==== Step 2: Bench Top V2 ====

Using the same rails and permanent magnet from step 1, but build a PSU and capacitor bank. Hopefully can deliver a higher-energy shot without ruining / welding the rails together.

===== See Also =====

[[ ELF-A ]]