New Bern, NC – In a typical year, the mechanical engineering and operations management students of Kirk Keller at Wayne Community College in Goldsboro would be doing the following.
"Just like most of the community colleges in the area, making widgets."
Not this year. This year their hands-on project had a bit more "bang" than their typical widget-making. This year the students got up close and personal with a cannon more precisely, the carriage and chassis needed to support a 5200-pound replica cannon at Fort Macon State Park. The replica cannons at Fort Macon add a great deal of realism to the Civil War-era fort, but its coastal location was hard on the wooden carriages that supported the cannons, requiring replacement every few years. Looking at having to pay out in the neighborhood of $90,000 for two wooden carriages, park officials heard about the success the National Park Service had with aluminum or steel carriages, then placed a call to Kirk Keller.
"We were trying to duplicate a wooden carriage of the period, and due to the degradation of the salt air and sea that the fort is exposed to, using aluminum we had to decide what types of materials to use, whether it would be aluminum or stainless steel, and then to determine what would be the best for that type of use."
In addition to deciding what type of material to use, they had to have a plan regarding what to do with those materials, and it wasn't as simple as opening a file drawer at Fort Macon and pulling out the original blueprints for the Civil War-era carriage and chassis.
"Some of the language that was used and some of the information that was not available so we had to try and interpolate the prints that were given to us to change over into modern CAD drawings. It proved to be quite a challenge but one that we overcame and came out with 40 beautiful prints that had plenty of information that could be used to make a carriage by us or for someone else to duplicate."
They also had to factor in practical use of the cannon. No, tourists won't be coming under assault from 32-pound cannon balls fired by the replica cannons, but the cannons are on occasion loaded with 5-pound charges of gunpowder and fired, which produce a large bang, a lot of smoke, and stress on the carriage.
"We also did some research at Fort Fisher in Wilmington and determined the amount of rollback that they would get from the compression of firing and determine what five pounds of black powder would do in a rollback. So therefore we duplicated the same thing under the conditions using modern CAD information that we can do in SolidWorks and determine what the safety factor and then you know how much weight it can support and you decide what cross sections need to be used."
All this has produced a carriage and chassis which will reside permanently at Fort Macon State Park with hopefully a much longer life than the wooden works that preceded. It also has perhaps produced a widget-less future for students in Kirk Keller's classes as other state parks lured in by savings Keller estimates at $20,000 on this project produced for Fort Macon have expressed interest in similar projects for their parks. Keller expresses a lot of pride in what his classes accomplished and looks forward to doing it again. However, keep in mind Wayne Community College only produces carriages and chassis for cannons. For the actual cannon
"We did the carriage and the chassis. The barrel was done in Maryland at cannons on line. (You can get anything on line.) Isn't that awesome?"
Kirk Keller is an instructor in mechanical engineering and operations management at Wayne Community College in Goldsboro. I'm George Olsen.