Mark IV Experimental Results

The experiment worked perfectly for us. Even after 120 rounds the system still works like the first round.

The materials that we have tested were: Carbon Steel, Stainless Steel, Copper, and Aluminum
These materials were used because of their varying different properties and their cost

The data showed that high conductivity can mask the affects of ablation. Copper remained constant on average over the ten rounds, but experience the largest amount of damage.

The data showed that the specific heat capacity of the metals, or the metals ability to move heat that is heating one end of the metal to the other end for instance. Aluminum gained mass during this experiment by taking the molten aluminum foil being vaporized and basically welding itself to the aluminum rods. The aluminum was able to cool the aluminum foil being vaporized quickly to prevent damage to itself. This actually caused bubbles to be formed in the acrylic encasing the rods.

The data does not support the use of Cu-W, copper-tungsten alloys for use in applications involving metals that are in contact with plasma. This is because tungsten has a low specific heat capacity, meaning once the metal reaches its melting point, there is no place for the heat to go. That excess heat will eventually melt the alloy.

The data supports the use of a high conductive and high specific heat capacity alloy will be able to resist the affects of ablation and also keep its performance.

The experiment does show the need for further research. Economically feasible and energy efficient cooling systems need to be researched, and there is research being conducted currently by institutions on this subject. The material itself will be able to greatly help mitigate damage from high powered applications, but will not be enough to stop the amount of heat being produced from burning it. The material itself is still highly important in being able to transfer the heat to a cooling system connected to it.

Mark IV Circuitry Design

The most complex part of the experiment was the design of a charging system to generate the power needed to make plasma and accelerate it. Again, do not even attempt to make this type of device unless you know exactly what you are doing and seeked professional advice. The capacitors were the absolutely last parts of the system to be installed.

Mark IV Charging System

 

There was over 100 feet of wiring used for this system. The design itself was made to be feasible in the amount of time we had to build the system. There were multiple subsystems that were created outside of the main system, then installed in parts and integrated with the other subsystems. This allowed us to pinpoint an area that was not operating quickly by isolating the systems.

 

An ATX PC Power Supply was used instead of batteries because of how much less it costs. With 120 rounds being fired, it was not feasible to use batteries that make charging time slow down over use. With a constant power supply, we were able to speed up the experimentation process, along with the added perk of higher current coming out of the power supply. The higher currents create a stronger magnetic field in the camera circuits, despite being the same voltage. When current goes throw a wire, it creates a magnetic field. Thus, charging time was much faster than with batteries with the same voltage.

 

 

 

Mark IV Control Panel Design

The control panel for Mark IV is a critical part of the system. The computer is able to tell us how many camera circuits have power being supplied to, which can be controlled by using the buttons on the panel. This was very crucial in allowing us to work out bugs quickly and speed up the design process till we were able to safely operate seven camera circuits.

The control panel was also designed for the user in mind as the plasma discharge is a four stage process. The first switch shuts off all power being supplied to the circuits, the second isolates the capacitor bank from the circuitry, the third discharges the energy, and the fourth discharges the remaining energy stored in the capacitors after firing. This allowed us to speed up the experimentation process, and minimize risk.

 

Control Panel

 

Another critical aspect of the control panel is to regulate the voltage of the capacitor bank. Overcharging the bank accidently is a major risk, which the computer is able to prevent. A phototransistor was used to isolate the microcontroller from the capacitor bank to measure voltage. When the capacitor bank reaches 300v, the computer automatically turns off the power being supplied. Light from the LED on the camera circuits was connected to the phototransistor.

 

The computer was made using a Parallax microcontroller and programmed using BASIC Stamp. The coding took up five pages.

Mark IV Rail Gun Design

In order to minimize errors resulting from the rail gun design, we have decided to use a CNC to create the encasing. Due to the complexity of the experiment involving exchanging metal rods for each trial, a user friendly method was also easier to achieve designing the encasing on a CAD first.

 

AutoCAD Inventor was used for the design of the encasing

 

VCarve Vector Coordinates for CNC G-Code

 

Fully Milled Out Design

 

Two bolts were used to hold the rail gun together at the front, and a grip was used on the back. This allowed for easy removal of the rods after they have been spent.

Mark IV

Last year's experiment with Mark III brought out an interesting phenomenon with devices in contact with plasma. We've noticed a decrease of performance of the 300v trial over rounds, and figure it was due to the plasma damaging the rails, known as ablation.

That is where this year's experiment comes in! How do we prevent damage to metals in contact with plasma. This has also been an issue for the Navy's rail gun, magnetoplasmadynamic thrusters, NASA's mass drivers, etc. Mark IV was then designed, equipped with a full onboard computer for regulating the voltage of the charging system, the rail gun was designed using AutoCAD Inventor and vector coordinates for the CNC milling machine were done using VCarve.

Mark IV costs more than double of that of Mark III, however designed with numerous safety systems due to the amount of power it is designed to hold.

Mark IV Charging System

Photographic Mark IV Prototype Shot with Mark IV rail gun

Intial prototype test using Mark III rail gun on the Mark IV Charging System

 

 

Mark III

Mark II was a good working device, but needed more improvements to be used effectively in an experiment. That was when we added a microcontroller to better control the charging process, also for safety reasons. That was the major change, it still uses the same charging supply and rail gun.

Another improvement was in the wire connections to the rail gun, resulting in minimal arcing, thus more energy transferred to the plasma.

 

The picture here is a prototype test layout of Mark III connected to a computer.

Mark II

After Mark I showing that it is possible to accelerate plasma using a rail gun, Mark II was then made.

improvements were a more permanent layout, a box protecting the circuitry, and bolts connecting holding the rail gun together. Mark II operated using a wall switch to fire, a button to charge, and alligator clips that attach to Mark II afterwards connected to a resistor to discharge remaining energy. There was no microcontroller in this device.

The picture here is the process converting Mark II to Mark III.

 

Addition of bolts helped to further control the plasma

 

 

 

Mark I

This is where it all begun! It started out as a very crude device.

 

Mark I used acrylic with two steel bars sandwiched in between. The materials were held together by hot glue. This was designed as a prototype test to see if the experiment was feasible. Wires were connected to each rail to provide the current. A small piece of aluminum was vaporized inside the rail gun device, stripping away the electrons from the atoms, which is called plasma. The plasma is then easily influenced by electromagnetic fields created by the current going through the rails.

Mark IV Science Fair Experiment

This blog is made to help us better explain our project at the International Science and Engineering Fair. All of our work is original. Professional advice has been used for this experiment.

The blog will go over the significance of our research and how we got there.

We take no responsibility for anyone else trying to create a variation of our device. Professional guidance should be considered to minimize risk.

We are both Seniors at our high school and plan to pursue our engineering degrees.

--This is again a blog, not an official report of our project
-For further information contact Michael Sherburne at: smich95@vt.edu

--Updated 10/9/2013

-Michael Sherburne is currently attending Virginia Polytechnic Institute and State University
-Andres Artze is currently attending Embry-Riddle Aeronautical University at the Daytona Beach campus.

-Awards won:
-$5,000 Scholarship from Northrop Grumman at Fairfax Regional Science Fair
-Grand Prize Alternate at Fairfax Regional Science Fair
-Recogition from the American Nuclear Society at Fairfax Regional Science Fair
-$1,000 Cash Award from ALCOA Foundation at International Science and Engineering Fair
-$250 Cash Award from Virginia State Science Fair for 1st Place in Electrical and Mechanical Engineering

-Michael Sherburne/Andres Artze