Kumo 2.5

After not being able to find the Kayoumini frame in stock anywhere, I set off to build a 2.5" freestyle frame that would be compatible with existing camera mounts. I wanted to focus on durability while keeping the project open source to allow community additions/suggestions. I also know how difficult it can be to source parts, and custom cutting carbon fiber can be daunting/expensive, so I posted variants that can be printed thicker for increased rigidity (the ones in the photo are printed in PETG-CF and 2.5mm carbon fiber).

I wanted something more powerful and wind resilient than a whoop, while also being more durable and maneuverable than my 3" Tinytrainer V2. I designed this from the ground up around the HDZero AIO15 but any 25.5mm AIO or stack should work. I have versions with 20mm mounts in the files as well. Form factor is a slightly squished X geometry with a slam deck to keep the center of gravity low, improved durability and maneuverability.

CAD and STL files along with instructions and write-up on performance can be found in the github repo here:

https://github.com/kumoishibo/Kumo-2.5/

Example Build parts:

Component	Part
FC, ESC, AIO	HDZero AIO15
Motor	T-motor 1104 7500kv
Props	Gemfan Hurricane 2520
Antenna	NBD RHCP Honey Dipper Antenna
Battery	2S battery (450-580mAh)
Other	Active Buzzer, Flywoo OpenLager BlackBox, 110mm battery strap, battery grip pad, 9 or 11mm electronics standoff, M2 screws

Thoughts:

I've been flying various versions of this over the last month and I have to say this is by far my favorite thing to fly. It is quite punchy and gives me 3.5-5min of flight. I also tried with a 3S battery, but it ended up being a bit scary and drew quite a bit more power than I was comfortable with the 15A AIO. I also tried the 2540 Flash props and the Avan Rush, however the 2520 seemed like a nice balance between noise, power, vibrations, and flight time.
Example tune and vibration analysis can be found in the github.

I've also given this thing an absolute beating (including falling from a good 100'). I'll make a crash compilation video soon. In the meantime, here is a video of flight using the 3d printed version of frame.
https://www.youtube.com/watch?v=SoQ7cqYJ5XA

If you end up building one of these, tag me or let me know your thoughts! I'd eventually like to get this project more refined and potentially made available somewhere.

After dealing with the discomfort caused by the band and face foam, I decided to try my hand at designing a flip up strap that repurposes one of my old Quest3 straps that I wasn't using. This is using the cheapo KKCOBVR strap for the Q3.

I've tried using a FatStrap, different face foams and even printing a band riser to try to get the band over my ears. However, anything I tried would either bend my ears, rest uncomfortably on my ears/face, or simply resorting to a compromise where the band feels way to high on the back of my head.

After fiddling with this design, I've found that the HDZero almost requires you to squish your face into the foam in order to fully see the screen and eliminate light leak. This could also be caused by my specific face shape/size. Since there is no band or spring to press the headset into your face, getting the headset to sit vertically on your eyes and pushed far enough in to get the full view of the screen requires a lot of fiddling. Not to mention this thing doesn't collapse so it no longer fits into my backpack. I also may need to shorten the vertical mount so the halo strap doesn't sit right on my hair line, which also hurts after a while.

In comparison to VR headsets like the VIVE, Quest, Steam Index and even the Apple Vision Pro, the HDZero Goggles 2 still feels quite uncomfortable for me. I hadn't thought about posting the 3D files since I feel like this is somewhat of a failed attempt, but if anyone wants the CAD files, message me. At least this was a fun short experiment that let me test the limits of what is possible with the Goggles 2 and I'll likely just resort to using the default strap and have it sit too high on the back of my head or have it over my ears.