Glu4 4" FPV Drone Frame

I couldn't find a 3d printed drone to try out that I liked, so I decided to make one. I made it in the style of current freestyle fpv drones. 

I felt like a 4" was a good balance and unique enough. I wanted to make this frame durable.. as durable as plastic can be. I tried to make the frame strong so it's weighty, but the frame is stiff. I will experiment in the future with lower weight versions.

I'm new to fusion360 and trying to learn, so I thought a drone frame would be an easy way to learn. It's far from perfect, but I'm learning as I go.

                                             
Glu4 features:

*20x20 FC & ESC Mounting Holes 
*30x30 FC & ESC Mounting Holes 

*20x20 VTX Mounting Holes 
*25.5 x 25.5 VTX Mounting Holes

*12x12 Motor Mount Pattern

*19x19 Camera mount & should be O3 Compatible

For frame assembly you will need:
(4) M3 x 22mm - 25mm (22mm best, I used 25 barely worked; base plate)
(4) M3 x 16mm - 18mm (camera mount / rear stand off)
(2) M3 x 8mm (standoffs behind camera mount)
(8) M3 x 8mm (top plate)
(2) M3 nuts & (2) M3 washers (front two base plate screws)

I used screws from this kit: Link

To mount the stack, you will need:
(4) M3 x 25mm
(4) M3 nuts
(8) M3 vibration dampeners (gummies) Link 

To mount the motors, you will need:
(16) M2 x 12mm 
     9mm thick arms, about 12mm I would think.. may depend upon motor?
--(I used Emax ECO II 2004 2400kv motors Link)

For the standoffs & camera mount, you will need:

(16) M3 inserts 5mm Length / 4mm OD  (I got 2 packs of these Link)
      OR
(4) M3 inserts / one pack if you buy standoffs instead of make them. 22mm standoffs.
I believe these will work: Link

I haven't tried them, but they should work fine. I have a pack but I felt like it was cheating so I used 3d printed ones.

**Screw sizes don't have to be exact, you might be able to go each way a little.. mostly on the plus size a bit.
----------------------------------------------------
Print Material

PET-CF / PA6-CF / PAHT-CF? is probably going to be the most durable. I chose PET-CF. I think PA6-CF would be a great choice too. I'm sure it would work fine but just be less durable with PLA+. It's all plastic, so it's all going to break eventually.
PET-CF is heavier than PA6-CF, so it might be better for that. I chose PET-CF bc of the stiffness and low moisture absorption.

TPU for antenna mount.

Print Settings
I used a 0.6 nozzle for the CF filament.

Orcaslicer
0.2mm layer height
0.2mm bottom layer height 
6 wall lines on all pieces
95% 3d honeycomb infill
Bottom and top surface: monotonic line
Internal solid infill: concentric on arms 
                                 rectilinear on plates
Outer/Inner wall order
 On standoffs and camera mount I enabled support on the mount. And also made the top and bottom surfaces concentric pattern. 

Position your parts so they print with the best strength possible for best results.

*You may be able to use x/y hole compensation for a looser fit on your screws. A positive value makes the hole bigger in orcaslicer. By default, the holes need a dremel or you'll wear yourself out with a screwdriver. You can set 0.2, print a few layers, cancel the print and check the hole against your screw. 

----------------------------------------------------
Pre-assembly

You'll need to put the inserts into the camera mount and standoffs. I didn't have a press and didn't trust I could put the inserts in straight. So, I made this printed insert press. It's probably not the best, but it gets the job done. 



As I mentioned earlier, you may be able to use x/y hole compensation to adjust the screw holes to be looser. I used a Dremel and made the holes just a bit bigger. I assembled the base plate, arms, and bottom plate then used the Dremel to make the holes slightly bigger. I worked the screws a bit to loosen everything up as well. On the top of the base plate, you may need to trim the edges of cutouts for the screw heads so they fit better. On updates, I'll adjust them a bit more. I'm happy right now to just get it going and be trying it out. 

-----------------------------------------------------
Assembly

I'm not the best at explaining at things and I'm assuming you have prior drone knowledge.. I just wanted to warn you! haha

(1) Before assembling the frame, first install your flight controller / esc and vtx to the bottom plate because those screws will be inaccessible once you install the base plate and arms. 

(2) Place the arms into the base plate in their appropriate slot. (Depending on how your print came out, you may want to use a xacto or utility blade and clean out the slots if your not having good fit, same thing on the bottom of the bottom plate in the cutout for the arms.)
  *The number in each arm's file name is it's position 
 

(3) Place the bottom plate on top of the arms with the 1mm cutout for the arms facing downward. Use the standoffs and screws in the appropriate areas. 2 Screws, 2 nuts, and 2 washers are used on the front arm's rear connection. (Refer to above for where each screw goes, or be like me and trial and error it)


(4) Install electronics and motors. Make sure to run camera cable through the camera mount before mounting the camera and vtx. I cut an M2 vibration dampener / gummy into a couple pieces to use when mounting my camera. 

(5) Install rear TPU antenna mount. (I'll include the STEP so you can modify as I rushed this part)

(6) Route the XT60 through the XT60 cutout in the top plate.

(7) Secure the top plate with 8 M3 x 8mm screws. This leaves the holes behind the front standoffs empty. It was initially an oversight.. but I figured they might be useful one day and I left them.

I put a 3m velcro strip down the middle to attach my battery and a battery strap but you can use whatever you want. A battery pad is fine.. and a battery strap, you're ready. 

After you set it up in betaflight of course. 


Conclusion:

When in doubt, bring the Dremel out haha. I've gotten into fpv planes now so I lost a bit of interest in the project and it has taken me forever to post. It's not being released in perfect shape, but it's hard to make these things perfect for all possible things. I used a 30x30FC/ESC / Walksnail v2 & Walksnail 1s lite v3 / ELRS / Walksnail 14x14 camera in a 19x19 adapter. Hopefully, someone else can have fun with this too. And I'll know I'll be back with updates and more drone frames in the future! Thanks for giving it a try, I put a lot of work into it (probably way more than someone with any skill would have!)