initial DESIGNING THE Barrel support FOR THE CANNON
Before we could start building a cannon, the first step was to have a barrel support that would be able to hold the cannon securely and prevent any minor skews, shakes, or changes of position when it came to fire (1 degree change in position could result in missing the target by a few feet! A good support system was critical).
These pictures were the use of Mr. Twilley's information about inputing our dimensions into an online box maker and then cut it out via Onshape. (Onshape is a design tool that is used to sketch, adjust, and virtually assemble projects where the engineer is free to create all the pieces/parts they would print out on a 2D space, in order to create their 3D model)
Before this, I had never used Onshape before, but I got acquainted with the system with the help of my group members, independent notes, and practice.
Trials & Errors of the box's Holes
Since measurements in the engineering world are never actually what is given (a 4-foot board is, in reality, more like 3.8 feet), so we needed to create openings in our barrel support that would grasp our cannon firmly. Since we had no cannon of our own, we took measurements of Mr. Twilley's previously built air cannon from different orientations and took the average of this recorded data. Then we adjusted our Onshape design accordingly.
Using Onshape and the class laser, we began the trials of holes whose diameters we were testing on the barrel. The purpose was to find the precise and ideal opening size for the barrels of the cannon--Onshape designs allowed for more significant figures in the dimensions of the parts than were obtainable by the limits of human capability and measuring tools used.
The various holes on the bottom picture actually only differed by at most 5 thousandths of an inch! However, they had drastic physical differences. For example, the final diameter of the holes was 2.363 inches, but a 2.365 inch hole would be loose enough to freely spin around the barrel. Our 2.363" was the ideal measurement because it allowed for us to move the face of the box to our desired length, but was firm enough to prevent any wobbling, turning, or shifting once the cannon's barrels were through.
Scrapped connecting piece of barrel support
preparing and Assembling the Cannon pieces
For the reaction between the primer and cement to be immediate and permanent, we applied primer to both the "female" (the inner portions of a connecting piece) and the "male" (the outward-facing surfaces) parts of the connecting joints of the cannon.
These are pictures of us quickly putting the glued and primed pieces in their proper positions, and holding them firmly so that the joining could set, which was at least 30 seconds (but we held it for 45-60 seconds to make sure the bond was permanent since the reaction tends to move the materials from where you placed them--creating a "pushing back out" motion that would be detrimental if the seals between pieces were skewed).
Scrapped Designs for First Base
I think the flaw with these sketches were that they were not realistic for the materials we were given, the mechanics of how it would work, and the time we had to implement the ideas. With each explanation of "how would we do this?", a new problem would arise with "that doesn't make sense because...". Looking back, these ideas were complex but not impossible. With a larger window of time, we could have recreated the VEX robot gears that would allow the the pulling of the front of the cannon upwards, while the back of the cannon remained on ground level (best shown by the left picture). I believe these concepts were born when I came down to Mr. Twilley's other class and briefly collaborated with Charles. However, relaying the concept back to my team served to only find flaws in the theories.
Scrapped "Gravestone" Design
The concept was--as shown in the top left picture--the vertical structure would have holes on its sides in which the cannon arms would fit. These holes would be wide enough to hold the cannon (maintain its position at the different intervals) while also being curved enough to allow small adjustments once the cannon was mounted in the correct elevation. The top right photo introduced an idea that did make it into the final product: the circular mount. This would allow full 360 degree rotation and was fondly referred to as "Ol' Reliable". In the same picture was also another structure, called "the square base", that saw the end which was the base that had a circular indent in it where Ol' Reliable would be able to swivel without loosing position. The rest of the images were also early brainstormings that were well intentioned but were more figurative than they were realistic. For example, the drawing in bottom left and the one directly above it were hopeful in that we would create wheels with spikes/teeth that would be able to control elevation (looking back, this idea was expanded and executed in other groups' designs), but it was not efficiently applicable to the box we had produced, nor was it a sturdy structure, nor did we really have the materials. The photo with the text, "goals" also had feasible options such as the "sliding feet" that was our recreation of a tripod--hoping to angle the feet so that they could slide along a created gutter that would have holes in which we could place a pin to manipulate the elevation of the entire structure--and also introduced undeveloped versions on the "triangles" that could hold the base structure at the bottom, as well as the concept of having the angle of elevation be determined by a rotating device.
Designing "Gravestone" Base
Inspiration for New Base Design
Sketches for "Arc" Base
Designs for Arc Base
Getting that Perfect Fit
When we were outside testing our air cannon in the Battle Ship game, our team placed 2nd with 25 points (acquired from hitting the square surrounding tarp and hitting the lid of the target).