Portable Mass Portable Mass DriverDriverPresentation by:Presentation by:

Brad GarrisonBrad Garrison

Overview: Mass DriversOverview: Mass Drivers

Classification of devices that Classification of devices that use electromagnetic forces to use electromagnetic forces to propel an objectpropel an object

More efficient than existing More efficient than existing means of propulsion.means of propulsion.

A Brief “History” of Mass A Brief “History” of Mass DriversDrivers

Current Development:Current Development:

Navy/Army Navy/Army ResearchResearch

Amateur ResearchAmateur Research

Future PossibilitiesFuture Possibilities

Peaceful UsesPeaceful Uses Military UsesMilitary Uses

Rail Guns

Electro Thermal Chemical Guns

Ground Based Mass Drivers

Orbital Mass Drivers

Spacecraft Based Mass Drivers

Types of Mass DriversTypes of Mass Drivers

RailRail

CoilCoil

GaussGauss

DiskDisk

Project MotivationsProject Motivations

Interest in Interest in electromagnetism electromagnetism

Little research being Little research being conductedconducted

Current designs are Current designs are repetitiverepetitive

Project GoalsProject Goals

To construct a Gauss/Coil Gun that is To construct a Gauss/Coil Gun that is portable and easily operatedportable and easily operated

For the projectile to have a muzzle velocity of For the projectile to have a muzzle velocity of approximately 50m/sapproximately 50m/s

All components will be powered by a single All components will be powered by a single rechargeable batteryrechargeable battery

High rate of fire (60rpm)High rate of fire (60rpm) Extremely durableExtremely durable Completely safe for anyone to useCompletely safe for anyone to use

Possible DesignsPossible Designs

Coil GunCoil Gun

Rail GunRail Gun

Rail Gun LimitationsRail Gun Limitations

High “recoil” forceHigh “recoil” force Extremely high temperaturesExtremely high temperatures Armature vaporization Armature vaporization Expensive materialsExpensive materials More applicable to larger designsMore applicable to larger designs

Coil GunCoil Gun

Lower operating temperatures Lower operating temperatures than Rail Gunthan Rail Gun

No projectile vaporizationNo projectile vaporization Lower, more manageable “recoil” Lower, more manageable “recoil”

forcesforces

Coil ParametersCoil Parameters► NL : Number of Layers > 30NL : Number of Layers > 30 -- Inductance will be -- Inductance will be

unreasonably large. unreasonably large.

► LL : Low Inductance, < 5 uHLL : Low Inductance, < 5 uH -- Unusually low inductance -- Unusually low inductance because the wire resistance had to be small in order to get the because the wire resistance had to be small in order to get the target current. This happens when the goal is very high current target current. This happens when the goal is very high current with a low voltage. with a low voltage.

► TC : Time Constant > 2.0 msec TC : Time Constant > 2.0 msec -- Current rise time is too -- Current rise time is too slow.slow.

► OR : Outer Radius > 1.5 inches OR : Outer Radius > 1.5 inches -- Too many layers of large -- Too many layers of large wire. A smaller wire size will give a higher current density in a wire. A smaller wire size will give a higher current density in a smaller space. smaller space.

► CD : Current Density > 1000 MA/m^2CD : Current Density > 1000 MA/m^2 -- Practical value for -- Practical value for copper wire to limit the heating.copper wire to limit the heating.

Start PositionStart Position

Coil Cutoff Coil Cutoff

Coil ShieldingCoil Shielding

Projectile DesignProjectile Design

Maximum Volume with Minimum Mass

Ferromagnetic

Silicon Steel: the ideal material

Drawbacks of Existing Drawbacks of Existing DesignsDesigns

Most are driven off of Most are driven off of AC power making AC power making portability impossible.portability impossible.

DC designs operate at DC designs operate at a much reduced a much reduced power.power.

All have a very low All have a very low rate of firerate of fire

Most are dangerous Most are dangerous to useto use

All are very fragileAll are very fragile Capacitors used are Capacitors used are

expensive and heavyexpensive and heavy

Preliminary Design Preliminary Design ComplicationsComplications Barrel must be strong enough to Barrel must be strong enough to

withstand compressive force of the coilwithstand compressive force of the coil Capacitor banks can not provide Capacitor banks can not provide

pluses fast enough for the desired rate pluses fast enough for the desired rate of fireof fire

Capacitors may fail after repeated useCapacitors may fail after repeated use Heat build upHeat build up

Initial DesignInitial Design

Initial Design Initial Design ComplicationsComplications Induction coil produces high voltage pulses Induction coil produces high voltage pulses

not high current pulsesnot high current pulses Electromagnets will drain the battery even in Electromagnets will drain the battery even in

standby modestandby mode Optical gates will further drain battery and Optical gates will further drain battery and

introduce more fragile components into the introduce more fragile components into the designdesign

Microprocessor vulnerable to magnetic fields Microprocessor vulnerable to magnetic fields and heatand heat

Second DesignSecond DesignInduction coil replaced with photo capacitorsInduction coil replaced with photo capacitors

Electromagnets replaced with permanent magnets utilizing principals of the Gauss RifleElectromagnets replaced with permanent magnets utilizing principals of the Gauss Rifle

This eliminates the need for photo gates as wellThis eliminates the need for photo gates as well

Second DesignSecond Design

Charge BoosterCharge Booster

(example is using a bank of 20 1.2V 0.25Amp AA batteries)(example is using a bank of 20 1.2V 0.25Amp AA batteries)

Charge indicatorCharge indicator

► The indicator will The indicator will signal when the signal when the capacitor is fully capacitor is fully chargedcharged

Parallel ChargingParallel Charging

Resonance ChargingResonance Charging

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

Possible ProblemsPossible Problems

►Fragility of permanent magnetsFragility of permanent magnets►Resistive heating of the coilResistive heating of the coil►Over working the capacitorsOver working the capacitors►Battery lifeBattery life

Future ImprovementsFuture Improvements

►Optimized coilOptimized coil►Heat sinksHeat sinks► Improved indicatorsImproved indicators

ConclusionConclusion

►Coil guns are not practical for portable Coil guns are not practical for portable designs.designs.

►SuperconductorsSuperconductors►Specialized Capacitors/SemiconductorsSpecialized Capacitors/Semiconductors►New coil designsNew coil designs

►Advanced batteriesAdvanced batteries

ReferencesReferences

1. anothercoilgunsite.com1. anothercoilgunsite.com

2. coilgun.com2. coilgun.com

3. powerlabs.com3. powerlabs.com

4.mgc314.home.comcast.net4.mgc314.home.comcast.net

5. scitoys.com5. scitoys.com

Questions?Questions?