"The NoStress" - flexible TPU 5'' racing drone frame

It's on the heavy side (unexpected, right?!), it weighs about as much as a 5'' freestyle drone with a GoPro. Also, it's not quite as flexible as you might think; it's actually quite sturdy.

Tuning

I have since learned that the frame suffers from vibrations on yaw axis when run with noisy motors. To solve the issue and avoid runaways, you will need to set D on yaw axis to 0. The rest can be tuned as necessary.

Hardware

Made to accept 22xx and 23xx motors. Two stack size options.
You'll need some zip ties, four 25mm standoffs and eight 8mm or 10mm M3 screws to assemble the frame.

Video

Here's how it rips on a track: https://www.youtube.com/watch?v=JDVNW3v9kEc
And here's some other drones chasing The NoStress: https://www.youtube.com/watch?v=IqO0G39QlE0

Important note about print settings

When reading the description below, check the right pictures above to understand what I'm trying to explain. It's important you understand the "why" or you risk wasting a lot of filament. You've been warned.

Plates

For top plate, choose whichever stack size you prefer (20x20 or 30.5x30.5) and print it in a stiff filament. My filament of choice for this is Nylon+CF but pretty much anything else should do. Same goes for the bottom plate, stiff filament.

Fin and body

The turtle fin and body are both to be printed in TPU. For the fin, I suggest going with about 15% Gyroid infill and 2 walls to keep the weight down and make it nice and squishy.

Printing the frame body

Print the body upside down. Supports only needed in the motor holes.

These are my settings on a 0.4mm nozzle:
Layer height: 0.25mm
Line width: 0.6mm
Wall lines: 2
Top / Bottom layers: 5
Infill density: 8%
Infill pattern: Grid
Connect infill lines: yes
Supports: yes, only bed
Adhesion: 10 line brim

Each of those is there for a very particular reason. I've done some testing to get to these values.

Variable infill in motor holes

You will want to place a "support blocker" in all 4 motor holes and rotate it 45 degrees. Then change the blockers to meshes that allow you to edit overlap settings and set the following:
Infill density: 100%
Infill pattern: ZigZag

You're not blocking supports (which totally need to be there). You're setting variable infill. This is so because you want the area where motor screws go through to be as stiff as possible, so we need to put 100% infill there.