Ok, this is now done. For maiden use I have to wait until weather will get warmer. It might take 6 months or something. I still made some changes to design and then printed final version. Some notes regarding printing & actual installation:
- Use infill of approx 70%
- I used temp 205c
- Use normal speed, ie. do not use faster than normal speed
With these settings and my Miniboy this thing takes approx 2-3hours to print. Then actual installation is breeze.
- Final weight including MG-14 servo is 32g but this varies with printing settings
- All holes must be drilled for final spec. STL-file contains holes set so that servo screws are 2mm, installation holes are 2mm and hook pin is 3mm.
- I used 3mm brass tubing for pin with piano wire epoxied into it for servo actuation, I drilled pin hole to 3.5mm
Just as christmas is approaching I decided to set this to public download. You can copy it from aerotow S 06 (I had to put it into .zip file as wp does not allow .STL-files as media files). As 3d-printers are somewhat rare I also set up shapeways account so that you can get it printed. You can find it here. Actually, I have not printed this using shapeways, but they make great models out of normal .STL-files so this should work well. But just to be cautious I set this product to beta. If there are problems pls. let me know. Also, I am well aware that the use of MG-14 is a bit risky, but this is inteded for light aerotow of light planes etc.
Some pics of final sprint are below.
This is first design I have done with 3d-cad. Or actually I have done several ‘things’ which are used in several places, but this is first which has any further use. I am quite happy with Autodesk Fusion 360, but the learning curve was quite steep for me, I have long history of 2d-cad work and model aeroplane design. This new tool is an new tool requiring adaptation of workflow and different mindset.
Still, final design looks kinda spiffy 🙂
Final disclaimer : this has no guarantee whatsoever. It might work in it’s inteded use or then again it might not.
Edit : I added video of Z-400-maiden. It was year 2008 and weather was bad. Really bad.
One useful detail when comparing variants is to separate the printed housing mass from the servo and metal hardware. The reported 32 g is the assembled total, so changing filament density should not scale all 32 g. Also, 70% infill does not mean 70% of the fully solid CAD mass: the walls and top/bottom layers contribute separately. For a revised Fusion design, a STEP export can provide the fully solid volume-and-density baseline; the slicer estimate is more appropriate for the actual print settings, followed by weighing the finished assembly. I help develop CADProps, which supports that STEP baseline with server-side processing. Neither a calculated mass nor the slicer estimate establishes the hook’s load capacity or release reliability.