Portable Mass Driver Presentation by: Brad Garrison

Overview: Mass Drivers Classification of devices that use electromagnetic forces to propel an object Classification of devices that use electromagnetic forces to propel an object More efficient than existing means of propulsion. More efficient than existing means of propulsion.

A Brief “History” of Mass Drivers Current Development: Navy/Army Research Amateur Research

Future Possibilities Peaceful Uses Peaceful Uses Military Uses Rail Guns Electro Thermal Chemical Guns Ground Based Mass Drivers Orbital Mass Drivers Spacecraft Based Mass Drivers

Types of Mass Drivers Rail Rail Coil Coil Gauss Gauss Disk Disk

Project Motivations Interest in electromagnetism Interest in electromagnetism Little research being conducted Little research being conducted Current designs are repetitive Current designs are repetitive

Project Goals To construct a Gauss/Coil Gun that is portable and easily operated To construct a Gauss/Coil Gun that is portable and easily operated For the projectile to have a muzzle velocity of approximately 50m/s For the projectile to have a muzzle velocity of approximately 50m/s All components will be powered by a single rechargeable battery All components will be powered by a single rechargeable battery High rate of fire (60rpm) High rate of fire (60rpm) Extremely durable Extremely durable Completely safe for anyone to use Completely safe for anyone to use

Possible Designs Coil Gun Coil Gun Rail Gun Rail Gun

Rail Gun Limitations High “recoil” force High “recoil” force Extremely high temperatures Extremely high temperatures Armature vaporization Armature vaporization Expensive materials Expensive materials More applicable to larger designs More applicable to larger designs

Coil Gun Lower operating temperatures than Rail Gun Lower operating temperatures than Rail Gun No projectile vaporization No projectile vaporization Lower, more manageable “recoil” forces Lower, more manageable “recoil” forces

Coil Parameters ► NL : Number of Layers > Inductance will be unreasonably large. ► LL : Low Inductance, < 5 uH -- Unusually low inductance because the wire resistance had to be small in order to get the target current. This happens when the goal is very high current with a low voltage. ► TC : Time Constant > 2.0 msec -- Current rise time is too slow. ► OR : Outer Radius > 1.5 inches -- Too many layers of large wire. A smaller wire size will give a higher current density in a smaller space. ► CD : Current Density > 1000 MA/m^2 -- Practical value for copper wire to limit the heating.

Start Position

Coil Cutoff

Coil Shielding

Projectile Design Maximum Volume with Minimum Mass Ferromagnetic Silicon Steel: the ideal material

Drawbacks of Existing Designs Most are driven off of AC power making portability impossible. Most are driven off of AC power making portability impossible. DC designs operate at a much reduced power. DC designs operate at a much reduced power. All have a very low rate of fire All have a very low rate of fire Most are dangerous to use Most are dangerous to use All are very fragile All are very fragile Capacitors used are expensive and heavy Capacitors used are expensive and heavy

Preliminary Design Complications Barrel must be strong enough to withstand compressive force of the coil Barrel must be strong enough to withstand compressive force of the coil Capacitor banks can not provide pluses fast enough for the desired rate of fire Capacitor banks can not provide pluses fast enough for the desired rate of fire Capacitors may fail after repeated use Capacitors may fail after repeated use Heat build up Heat build up

Initial Design

Initial Design Complications Induction coil produces high voltage pulses not high current pulses Induction coil produces high voltage pulses not high current pulses Electromagnets will drain the battery even in standby mode Electromagnets will drain the battery even in standby mode Optical gates will further drain battery and introduce more fragile components into the design Optical gates will further drain battery and introduce more fragile components into the design Microprocessor vulnerable to magnetic fields and heat Microprocessor vulnerable to magnetic fields and heat

Second Design Induction coil replaced with photo capacitors Electromagnets replaced with permanent magnets utilizing principals of the Gauss Rifle This eliminates the need for photo gates as well

Second Design

Charge Booster (example is using a bank of V 0.25Amp AA batteries)

Charge indicator ► The indicator will signal when the capacitor is fully charged

Parallel Charging

Resonance Charging ► Resonance charging will be used to conserve energy and to decrease the charging time

Possible Problems ► Fragility of permanent magnets ► Resistive heating of the coil ► Over working the capacitors ► Battery life

Future Improvements ► Optimized coil ► Heat sinks ► Improved indicators

Conclusion ► Coil guns are not practical for portable designs. ► Superconductors ► Specialized Capacitors/Semiconductors ► New coil designs ► Advanced batteries

References 1. anothercoilgunsite.com 2. coilgun.com 3. powerlabs.com 4.mgc314.home.comcast.net 5. scitoys.com

Questions?