FFC/FFD/Powerspec 3D Ultra Rear Fan Duct

Now New and Improved!
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I've updated this thing to now be angled slightly downwards, as well as making the opening a proper air nozzle to give the best flow. Additionally, I increased the contact between the fan output and the fan duct to make it a better seal and eliminate wasteful airflow.

I additionally made changes to the design to allow it to be printed in vase mode! Just make sure you enable 5+ top solid layers for best results.

Summary
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