This week all necessary parts for the QRM quadcopter arrived, and we test fitted them on the aluminum prototype frame. Everything fitted perfect, and we finalized the designs so that the frame could be machined out of carbon fiber.
Together with the parts ordered at Hobbyking we bought a couple of 100x300mm 1.5mm thick sheets of carbon fiber. We managed to nest all the parts on two of these sheets, reducing the waist material to a minimum. When machining carbon fiber the material that is chipped away are minuscule fibers that you really don't want to inhale. (not often anyway) The parts could be machined using a vacuum cleaner, but we chose to make a bath in which we can machine the carbon fiber under water. This was done purely as a dust collecting mechanism, and not as coolant.
As you can see above we tabbed the parts so that they wouldn't come lose while machining. Both sheets where machined on our home build CNC machine, with a 2mm spiral toothed solid carbide endmill, with a full-depth cut. Machining took about twenty minutes per sheet, and we recorded the whole process. The water got black almost instant, so the machining itself isn't viable. We fast-forwarded the movie, and cut out some parts. You can see the sheets being taken out of the bath at 1:40 and 3:00
After machining the parts, we started assembly. The video below is fast-forwarded, the real time was about one hour. The only thing left to do is to connect all the electronics, set up the control board and see if she flies!
The total ready to fly weight will be around 250 grams!
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