IARC 2011

IARC Troubles, Zero Clearance

It seems that during the design phase of my senior project, I cut a few corners in sizing my blimp. I established roughly what the external dimensions of The Emu should be in Pro-E last semester, but I was a little lax with accounting for the thickness of each piece of balsa. The end result was tighter spacings than I would have liked… but everything still fit. The area in question was for the servos and interfacing with the carbon fiber motor shafts. I intended to have two servos facing opposite directions mated to the carbon fiber shaft via a wire linkage, somewhat like a universal joint.

As you can see from the above picture, I barely had room to make it all fit. In fact, it was also nearly impossible to assemble. What I should have done is glued in the inner bearing column (green) by aligning it with the inside face (blue), instead the outside face (red). This would have given me an extra eighth of an inch on both sides. Regardless, I managed to complete the servo-shaft mating and glue it all in (with some forcible bending of balsa to make it fit).

I also took the time to make a little slot-like structure to hold the battery. I had been debating what would be the best way to hold a battery in the blimp and decided that making a platform to tie or glue in a battery would be unwieldy. In the competition, I planned on swapping out battery packs between runs. Sliding a battery into a properly fitting slot would probably be the most user-friendly option. I considered holding the battery horizontally or lie flat on the floor of the blimp’s control module, but decided that vertically would require the least amount of balsa. (In the past few days I’ve gotten REALLY stingy with how much wood I use, even though the difference is a few grams.)

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