Hachidorii XL Carbon Fiber Whoop

[Updates]

17/06/2025: All DJI O4 components are added. Currently still working on the Walksnail/Analog variants of the camera mount and camera hood. For walksnail, I've been using the Avatar HD Mini VTX V3 as reference. I've also added “Hachidorii XL_M2 12mm Tool Guide.stl”.

[Introduction]

The Hachidorii XL is a carbon fiber 84mm whoop frame that fits 45mm props designed by Ricebowl. It was designed primarily for digital systems like the DJI O4 lite, but will fit other VTX systems too. A full writeup on the frame can be found in RotorBuilds, including parts I used, and the frame can be bought from CNCDrones. Additionally, a build video can be found here [To be added] along side the Hachidorii Build Manual here [To be added]. PID and filter settings will be provided soon.

[File Naming Convention]

The files are named hopefully in a way that makes it easier to navigate through them. They follow the "frame_variant_component_additional details" and I plan to do this with future frames as well to make it easier to build up these drones.

• "frame" = Name of the frame [ie. Hachidorii XL]
• "variant" = some frames will have variants [ie. Hachidorii XL has TM and BM]
• "component" = name of the component [ie. Camera mount, Bottom Plate, etc.]
• "additional details" = sometimes the component is used for a specific part [ie. DJI O4] and sometimes I indicate its file type [ie. STL or DXF_1.5mm]

[Hachidorii XL BOM]

The Hachidorii XL kit from CNCDrones comes with the following parts:

• 4x M2 15mm Nylon Standoffs
• 8x M2 16mm BH Nylon Screws
• 6x M2 6mm BH Screws
• 4x M2 Nylon Nuts
• 1x Main Plate (T700)
• 1x 1.5mm BM Top Plates (T700)
• 1x 1.5mm TM Top Plate (T700)

The remaining parts can either be 3D printed except for the vibration dampening:

• 1x 3D Printed Ducts [Files in Thingiverse/Printables]
• 1x 3D Printed Camera Plate [Files in Thingiverse/Printables]
• 1x TPU Camera Guard/Hood [Files in Thingiverse/Printables]
• 2x Power Chains or Elastic Bands [Such as https://tinyurl.com/3r6n4a6v ]
• 1x 16mm by 16mm Silicon pad [Optional]
• 3x GEPRC Dampeners [Such as https://tinyurl.com/k2yj8k6f ]
• 3x M1.4x7mm Flange Screw [The ones you get on tinywhoops]

NOTE: I will be making the Hachidorii Build Guide to hopefully clarify and show the process of building the Hachidorii more clearly. However, feel free to message me if you have any questions. 

[Hachidorii XL BM and TM Layout]

General Layout of Hachidorii BM:

General Layout of Hachidorii TM:

[Camera Guard VS Camera Hood]

The camera guard and camera hood are both parts meant to protect the DJI O4 lite camera and are both printed in TPU. The camera guard is a thick TPU piece that wraps around the back of the camera, which has more protection on the back of the camera. On the other hand, the camera hood is more minimalist but still has some protection on the back but primarily covers the top of the camera. I personally prefer the camera hood more but some have liked the guard. 

[Power Chains and Elastic Straps as Battery Straps]

This is just my personal opinion, but I hope anyone trying out my  Hachidorii frames gives Power Chains a try as battery straps. Power chains are those elastics used for people with braces. Where I live (Philippines), they're easily sourced from online stores, come in long lengths so you have extra, and are relatively cheap. They're extremely lightweight, last a long time (I am still using the first set of straps on all my Hachidorii frames), and easily adjustable in tension. I find them to be reliable even for 2s builds like the Hachidorii XL. More information about them here.

[Material Choice for Ducts]

Naturally, I was concerned with the durability of the 3D printed ducts for my Hachidorii frames. Because of this, I did several tests to see if they're worth pursuing. First, I did two videos regarding materials, and those concluded with ABS and ASA being the best options. They're lightweight, relatively stiff, but still can manage some high impacts. Secondly, I also did some real-life testing, which proved to be insightful as my ANSYS simulations showed similar stress points. I designed the ducts as well as I could to address those stress points while keeping acceptable weight.

Please take note that, though these ducts can take a beating, you will eventually need to replace them. 

[Additional Important Notes]

[12mm vs 15mm M2 Nylon Standoffs]
The original design uses 12mm M2 nylon standoffs. However, to accommodate those who want more center space and the current stock of CNCDrones, the kit sold in their store uses 15mm standoffs. I'll be including a 3D printable tool guide (named "Hachidorii XL_M2 12mm Tool Guide.stl") for those who want to cut their 15mm standoffs to 12mm. I will make an update as soon as I've uploaded that additional STL.

[M2 Camera Screws]
The kit from CNCDrones includes two M2x6mm button-head screws, which will be used to secure the camera hood/guard to the camera mount. However, if you plan to build this with analog or walksnail (14x14 cameras), you may need longer M2 screws. I don't know yet how long, but I will make another update once the non-DJI parts are done.