On Wednesday we had a productive working meeting where we solved three problems in one go, working on the CNC Hot Wire machine, setting up a vacuum bagging system, and working on stop the chain skipping on the drivetrain.
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| The whole crew working on vacuum bagging and CNC hot wire equipment |
Wes had machined longer support shafts and lead screws to increase the working area of the CNC hot wire from 74 cm (29 inches) to 127 cm (50 inches), and he installed the part with the help of myself and Bob H and the Geoff helped us get the hot wire running with the software, and confirmed that all axes moved as expected.
We'll cut some test pieces next week using the new setup, which has a large enough working area to let us cut full-sized wing ribs for the airplane (meanwhile, Zach H cut some of our first full-sized wing sections out of foam using a different CNC hot wire machine, and discovered a glitch in the .DAT file we were using. We don't have photos of that. He'll be cutting more parts in the future)
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| Re-assembling the CNC hot wire machine with longer lead screws |
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| The finished CNC hot wire machine with 127 cm (50 inch) working area, getting ready to test |
Ihab and Geoff worked on setting up a vacuum bagging system with adjustable vacuum pressure, which will allow us to vacuum bag composites and other items requiring vacuum bagging (such as gluing the plywood on the ribs).
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| Setting up the vacuum bag system |
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| Vacuum bagging pressure monitors, filters and valves |
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| The vacuum bag system in operation on a small sample section of horizontal tail rib foam |
Ever since we have had the static test rig set up, we have had a problem that slowing or stopping pedaling caused the chain to jump the sprockets, something that would obviously be inconvenient if it happened in the air while flying. Our original setup had a cage from a derailleur as the idler pulley, and it included a spring that we thought might be part of the problem. We had a whole list of possible solutions, and getting rid of the spring was one of them.
Grant hacked together a new idler pulley setup from scratch, that didn't include a spring, and it works beautifully -- no more skipping. Now we just need to make a final design and figure out how to mount it on the fuselage, while providing for some adjustment.
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| New spring-less, no-skip idler pulley prototoype |
-- Alec
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