Just a simple thrust tube for a Dr. Mad Thrust 50mm EDF. It has an 8% Diameter Reduction at the exit which should give you a good mix of speed and and torque. The tube is 50mm long and there is an extra 20mm that couples it to the EDF, while the optimal length is about 4x the diameter of the EDF which would be 200mm that simply wouldn't fit on my HK FlyCat. There are three different versions of the tube, V1 which is only the tube with no wire holes or mounting bracket, V2 that has the mounting bracket for the FlyCat, and V2 Wire Hole that has a hole for my motor leads to go through. I included the STL's for all the designs as well as the 123D designs so you can make your own. Below is a transcript of a .txt file I have with all the dimensions of the EDF and tube. Also I designed this with a lot of help from THIS thread, its super useful and I recommend you check it out.
EDIT: Added a model, V3 Side Plates, that has plates that come out of the edges for mounting on flat 5mm thick foam.
Dr. Mad Thrust 50mm EDF Dimensions
Outer Housing Diameter: 53.5mm
Inner Housing Diameter: 51.75
8% of 51.7 = 4.1mm smaller end
Thrust Tube Dimensions
Beginning Diam: 51.7
End Diam: 47.6mm
51.7 + 2 = 53.7
47.6 + 2 = 49.6
4.1 / 2 = 2.05
+2mm for wall thickness, really it should be +4mm to
make 2mm walls all around
FlyCat Motor Mount Wood Block Dimensions
10.5mm x 10.5mm
Supports are obviously need for V2 and V3 models because of the mounting bracket and how it overhangs, V1 doesn't need supports.