EDIT: 1.3 frame added with sturdier legs.

EDIT: I've added the 1.2 version of the frame which has slightly sturdier ducts which allows it to lose one of the motor arms which seems to make the whole thing more robust is crashes as the ducts flex rather than put stress on the motor mount. This version also uses screws to mount the FC to the frame rather than a friction fit. Mount the FC from the bottom. I've also added a lighter weight version of the camera mount / top cover.

Parts:
FC: http://bit.ly/34oPuYs
Motors: http://bit.ly/2tqFUYf
Camera: http://bit.ly/2Mgm0px
Props: http://bit.ly/2PNvKs6

Here is a lower rider version of my 66mm whoop frame designed for printing in polycarbonate.
It's taken ages to design something that actually stands up to crashes (this has taken many hits without breaking) and has better flight characteristics than stock Whoop frames.

It's far stiffer than stock frames I've tried due to the material (polycarbonate) and the design of the frame with vertical braces holding each motor in place.

This leads to great flight characteristics with no discernible washout.

The price for this great flight characteristics is about an extra 2g of weight over a stock frame (around 5.5g) and you need to be able to print pure PC.

I fly this at S so those extra 2g don't really matter - and man this flies great, even with relatively big 2S batteries...