By Richard Howell Kevin Ryland Christopher Cox Yihan Pang Bryce Langlotz
Our design that we are creating is a rail-gun that will function as a launcher for planes off aircraft carriers and to supply space stations. This is unique in that instead of trying to shoot the projectile as fast as we can, as we would with a hobby railgun, we are trying to control the speed and the angle to preserve the safety of the aircraft.
Lack of a propellant! No explosions take place! Relatively safer!
The idea was created by a French inventor names Louis Octave Fauchon-Villeplee in 1919. The original name of the rail gun was the “Electric Apparatus for Propelling Projectiles.” This name was shortened to “rail- gun” later because the rails that are the main section of the device.
This idea was founded by German Ordnance Officer Joachim Hansler during WWII. These guns were never built as these theories were not completely defined for construction until late 1944. By this time the Germans were on the defensive and could not spare the resources to make a prototype.
In 1947, a report was done proving that the only problem the Germans would have had was that each gun would have needed more power than is currently being used by Virginia Tech. In 1950, Sir Mark Oliphant build a 500 Megajoule Homopolar Generator that was used as the power source for a large scale rail-gun that was built and used as a instrument for research.
Safety is paramount in this project. While we are creating the launcher, we make sure to only launch under very controlled circumstances. Heat is also a main issue. The electric current going through the wire will create a lot of heat. This is why we are using aluminum which does not melt as easily as other metals would. We also need both the rails and the projectile to be conductive for this launcher to work. This means the material that can be used are limited to good conductors.
We researched online and found different sites which showed us the fundamentals of how a rail-gun operates. We then incorporated different ideas of our own. We also decided we would make our rail gun relatively small compared to other rail guns due to our budget constraints. We will use our rail gun as a model.
The power source for our rail gun is around 40 capacitors from old cameras wired in parallel. We used 22 gauge wire and a bread board to wire the power source together. The base is made of wood so that we can easily manipulate it with the tools a our disposal. The rails are aluminum because it does not easily melt and is a good conductor of electricity, aluminum is also not ferromagnetic.
We wired all the capacitors in parallel on the breadboard and soldered connections to the power mechanism. We cut the base to be a triangle that inclines the rails at an angle of 45 degrees to get the maximum distance from our launch. To do this we used some trigonometry to find that we needed to cut our 18 inch boards so that the base and height 12.7 inches, while our hypotenuse remained 18 inches.
In our original calculations, we did not consider the thickness of the boards. We had an issue with the wiring of the power supply that caused it not to function properly. We had a problem with getting the current to discharge. The indicator light showed up so we knew the charge we there we just could not get it to discharge. The energy from the source is being dissipated by the length of wires. The nail is being welded to the sides of the aluminum rails when we discharge all the electricity. The projectile we were originally using was the wrong material.
For the problem with our dimension calculations, we premeasured the dimensions and re-evaluated the lengths. For the problem with the wiring we took out the capacitors and troubleshooted the circuit to find a disconnect in the wires. For the problem with discharging we took out the switch to test if it was the problem and found a disconnect from switch to the breadboard. We changed the projectile to aluminum and positioned it in different ways, but we are still unable to fire the rail gun.
With our first test we got a spark across the nail. The nail was blackened by the shock and seemed to be melted into the aluminum slightly. The nail was snug were it had been loose before the spark.