
Figure 1 illustrates the crux of the problem with the design. What looks aesthetically pleasing in the virtual world doesn't necessarily correlate to a practical design in reality. Left, we have the side profile of the sentry gun. The middle shows what the model essentially looks like from a force analysis: two "real" ground supports, one distributed load, and one concentrated load with a pivot at the intersection of both leg supports. The right shows the resulting problem: the rear assembly starts to deflect if the support isn't properly reinforced.
Figure 2 demonstrates all the key points of interest in making the arm that supports the ammunition housing for the sentry gun. Due to the angled shape of the arm, there are multiple points of interest where the builder will need to take into account material shear and deflection. The bottom pivot pin takes on a substantial lateral load and not much concern for axial loading. Threading a rod through a circular ring solves the problem of shear located where the pin meets the support arm.
At a small scale, there are not many ways to reinforce a series of thin rods connected to cylinders. I've resorted to Loc-tite glue to be a pseudo welding compound. Works fine, but for larger versions of this model, the rods would need to be solid components with the cylindrical sections. The right half of figure 2 illustrates the only method of corrective action taken to counter the lean: reinforcing the arm base with a wooden rod. The component in that region had begun to deteriorate and delaminate. The rod strengthened the region.
At a small scale, there are not many ways to reinforce a series of thin rods connected to cylinders. I've resorted to Loc-tite glue to be a pseudo welding compound. Works fine, but for larger versions of this model, the rods would need to be solid components with the cylindrical sections. The right half of figure 2 illustrates the only method of corrective action taken to counter the lean: reinforcing the arm base with a wooden rod. The component in that region had begun to deteriorate and delaminate. The rod strengthened the region.
1 comment:
Your work and blue prints of this level three sentry gun are incredible, my mind is absolutly perplexed by your work, a big well done to you!
Post a Comment