NACA Duct to 1 ½in Outlet

A friend needed a NACA duct for his racecar, so I made one. It's a small 1.5in hose opening because it is only needed for helmet airflow, mounted on the side window. I'm very happy with how it came out, so I decided to share. Template file also included.

In its current form it is approximately 7.7in long and 3.75in wide. If a shorter one is needed, in your slicer it should be easy to just shorten the Z height. That should not affect the hose opening. You will need to drill the holes out some, but that should be easy.

 Using a .4 nozzle the outer walls are 3 walls wide. 1/8in holes for 1/8in rivets.

The original prototype was printed in PETG, and it is very stiff, but this final version is printed with Matterhackers brand NylonX(PA-12-CF) on a Bambu X1E. The PETG one is actually plenty strong enough for this use case, I just wanted to make it out of some more fancy filament.

These are my NylonX(PA12-CF) settings that work very well for me. I included these settings in a Bambu .3mf.

.4 Nozzle

.12 layer height

6 walls to make it 100% infill

Lightyear G10 build plate

Elmers Purple glue stick

60°C Bed temp

60°C Chamber temp

30% Chamber exhaust fan

20% Part fan on overhangs

Max speed of 50mm/s, as low as 25mm/s

Inner and outer brim

Painted on supports

Very dry filament printed directly from a filament dryer

In total it weighs less than 40g

These PA-12-CF settings are probably conservative, but I'm fortunate and not time constrained when printing. So I usually go slower than what might be possible. Printing ‘slower’ has worked well for me when printing the “more complicated” filaments.(ASA, Nylon's, TPU) I feel it has allowed me to succeed on many first time prints and not have to needlessly waste filament. I'm sure this can be printed faster but the slow speed really helps with layer adhesion and shrinkage/warping in my opinion. The heated chamber on my X1E helps, but I've had great success with my X1C with an hour or so of preheating. I have not yet tried to print this on my X1C, but I have had great results with NylonX without a heated chamber on other models. I bet it would print just fine with the correct preparation.

Cheers, and thanks for looking!