Crossfire 2 Tube arms

thingiverse

This is an experiment to test the durability and structural integrity of my latest crossfire project. As seen here: https://www.thingiverse.com/thing:234867 I've been working tirelessly to streamline this design and boost its stiffness while cutting weight. Despite being still a work in progress, I'm willing to share it with you for feedback. The arms have been fabricated from 16mm thin wall aluminum tubing, precision cut to fit together seamlessly. I'm utilizing a UBlox 6 GPS module from China, attached via a sturdy 5mm piece of tubing. You may notice screws on the enclosure; rest assured, they're made of stainless steel and won't interfere with the compass. However, for optimal performance, nylon hardware would be preferred over these stainless screws. Additionally, I've taken the liberty of applying copper tape as a shield to the UBlox PCB inside the lower section – please be cautious not to create any shorts in the process. To accommodate varying motor requirements, I designed three distinct motor mount options: 16x19mm and 25x25mm versions with adjustable hole spacings, plus one with a dedicated dimple for motor shaft alignment. Afrotech 30 Amp controllers are powering this project; they're securely attached via 'clip' on holders which provide excellent airflow for cooling – albeit slightly tight, these clips appear to offer a significant advantage. For precision work when drilling the arm mount holes, I created an integrated drill guide and support piece compatible with standard drills presses. You'll notice specific tube dimensions illustrated in the images included below; take note not to apply excessive force when drilling, as evidenced by last pic – this can result in unwanted dimpling on the tubing. Tubing cutting should be carried out at a moderate pace using precision tools, particularly with tubes measuring 16mm and above. Arm root mounts come in two distinct parts, with one standing 25mm tall and secured through a clamping system. Long 3mm fasteners facilitate smooth base assembly and ensure stability via the nut pockets located on the back for future convenience. In regards to landing gear setup, a "McGyver's" solution had to be applied in order to avoid interference with tubing, however functionality remains intact. As an afterthought, I also designed an APM power supply holder; a simple piece printed using a versatile sbec which enables mounting between the lower plates, offering two slots for small-sized sbec units. Print and build guidelines can be found here: Recommended print parameters include: - Layer height: 0.3mm - Infill: 20% - Print temperature: Medium-hot (your judgment call) Most items printed with flexible PLA plastic, however feel free to make your own choice of filament. Additional specifications regarding hardware can be seen below: Required hardware list includes: 16mm tubing x2 pieces; wall thickness is 0.016". 5mm (3/16") tubing; for GPS mount application Various cap screws in stainless – used as mounts and fasteners. Motor support mounting material; choose the appropriate tube sizes depending on motor needs All 3mm hardware (available here: http://stores.ebay.ca/northern-supply-2012?_rdc=1) Screws for your specific motors. Nylon components were also integrated for increased durability. For this setup to function flawlessly, the use of RTV silicone will ensure optimal connection on motor mounts, arm tubes and other delicate assembly points – kaptan tape will work just fine in emergency situations. Note that there's no securement for GPS unit – using it might lead to issues down the road; as stated before RTV adhesive may help avoid such conflicts. It was found that certain parts require a small dab of RTV silicone to securely fasten; take this precaution in future modifications to guarantee robust performance.