Monday, December 29, 2008

This (last) Week(end)'s Project: Building a Sentry Gun

It has been about 5-6 days after starting construction of the Team Fortress 2 Level 3 Sentry Gun. I've consumed a total of 38 Magic: the Gathering cards (which I've finished all the structural aspects with) and about 10-20 sheets of 110lb Cardstock (I've lost count). I've also used about 17 bamboo skewers. I have reached 8 pages of documentation covering the design and construction of various components. This paper model outclasses the minigun "Sasha" in terms of complexity and weight and outnumbers it in unique components needed for construction. I dare say, it uses more Magic: the Gathering cards to construct than Lia.

This stage currently is missing the following details:

Electrical wires
End caps for holding the rotating minigun barrel assemblies to the housings
Middle redundant feet supports
Rockets (x4)
Ammunition feed belts
Misc decorative fasteners and bolt heads

I'll elaborate on the finer details of the construction after I finish this task. So far, in order to properly assemble the sentry support, I had to glue down parts now. Unfortunately, if I do that now, painting would be difficult to do due to the crevices and small clearances. Therefore, my original plan of leaving it unpainted to show off the materials used in the construction fizzled. Right now, there's a blue wire holding the front legs/support column to the frame. There's a very logical reason for this: the design I've based this off of isn't feasible in real life.

The center support column is composed of a cross shaped piping piece, with two ends feeding into the frame. These parts also conveniently form the pivot for the front legs, which are attached to the middle post by the lower struts. There's nothing holding them to the curved frame, so when weight is applied to the post, it creates a moment on a non fully constrained support, causing slip. Think of a board resting on wall. Apply a load to the top, and the bottom will slide out, causing the ladder to fall. I'll do a proper over-analysis of the sentry design later as well, once the zeal of completing this monstrosity ends.

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