Coilgun Rifle finished

TheMerovingian, Mon Oct 30 2006, 08:39PM

This is my second coilgun. I work on it from 3 years ago (including concepting, designing, prototyping etc)

Specifications:
model: EMR0260S03HBP1TA
ammo model: 5,5x40SS
Stages: 3 (plus injector stage)
Type: Diagonal halfbridge of IGBT's and Ultrafast diodes, optically controlled with regulated pulse width
Type of loading: manual reloading with lever , 8 rounds magazine size
5mw laser pointer
charge time: (cold start 8 seconds, warm start 4 seconds)
power source 12V, 2,2AH ultracompact Sealed Lead-Acid battery
Extra functions:
1)Indication of projectile presence in the injector and prevents dryfires
2)Indication of charger state
3)three-function 10 led bargraph displaying cut-off voltage, actual average voltage, charging activated

Total energy: 260J @ 300V
Used energy per shot: 114V @ 300V
Exit kinetic energy: 6,5J
Exit speed: 41,5 m/s
Projectile mass: 7,4g
Projectile diameter: 5,5 mm
Overall efficiency: 5,8% (1,98% preacceleration injector stage, 7,07% first HB stage, 10,9% second, 10,4% third)
Kx = 14,60
Ko (taylor stopping power) = 0,256
1/14 th of the 9mm parabellum stopping power (3,5 points taylor)

As you can see the halfbridge has high efficiencies in the latter stages (also it can be tuned for velocity or efficiency, i searched a compromise on the pulse width)

All this using a conducting barrel and projectile and with no external iron.
I think that using the halfbridge topology together with controlled pulsetime, non-conducting barrel, external iron will rise the overall efficiency to higher values, at the cost of complexity though