BIG Spinner for LOW Drag? | Carbon Fiber Spinner Design & Install on the DarkAero 1!

Learn how to make your own high-quality carbon fiber parts: https://darkaero.com/courses

We finished installing the carbon fiber spinner for the DarkAero 1 prototype on the Airmaster propeller hub. The spinner was designed in Onshape cloud CAD.

The mold for the forward spinner bulkhead was CNC cut from MDF on our AVID CNC router. The mold was coated with mold release and then we were able to make the forward spinner bulkhead from carbon fiber using a vacuum resin infusion process. Holes for the blades were cut in the spinner using a Milwaukee oscillating cutting tool.

Recommended Tools for Carbon Fiber

Cutting
Oscillating Tool - https://amzn.to/3s7K8hm
Oscillating Tool Batteries - https://amzn.to/3ojBB7G
Oscillating Tool Blades - https://amzn.to/35Pkwfy

Sanding
Durablock Sanding Tools - https://amzn.to/2Mrg7IZ
80 Grit Sandpaper - https://amzn.to/3oi0NM0

Safety Gear
Respirator - https://amzn.to/3btSJVo
Respirator Cartridges - https://amzn.to/38HV3GG
Hearing Protection - https://amzn.to/3oobbCC
Safety Glasses - https://amzn.to/2XJu8DX
Nitrile Gloves - https://amzn.to/39Go6K3

A new aft bulkhead was also infusion molded and the bolt circle pattern was cut on our CNC router to ensure the pattern was accurately located. With the new parts fabricated, we were able to assemble everything. We used Click Bond nut plates and countersunk screws to hold everything together.

The spinner on the DarkAero is larger than what is typically found on light aircraft. This was done for aerodynamic reasons. The larger spinner allowed us to make a more streamlined shape for the nose and cowling of the airplane. Ideally, the nose of an airplane would be shaped like a torpedo or teardrop for aerodynamics. However, attaching an engine and propeller to the front of the airplane forces the shape to deviate from the aerodynamic ideal. The most popular light aircraft engines are air cooled and use a horizontally opposed piston configuration. These engines are typically pretty wide and the cowlings that are built to enclose them also end up being wide and somewhat square shaped, especially if a small spinner is used. The 200hp UL Power UL520iS engine we selected for the DarkAero 1 is about four inches narrower than conventional airplane engines, which helped us create nose geometry closer to the ideal shape. With the cowling designed around a large spinner, it was possible to make a smoother geometry transition from the spinner to the cowling, which helps reduce aerodynamic drag.

The drawback of using a larger spinner is overcoming potential imbalance issues. The propeller and spinner need to be dynamically balanced. The rotating mass of the prop and spinner needs to be evenly distributed around the rotational axis, otherwise there would be vibration. Vibration is bad for the aircraft and uncomfortable for the pilot. Balance with a small spinner is dominated by the propeller but with a larger spinner, the balance of the spinner itself comes into play.

We tried to minimize inherent vibration in our spinner be eliminating any asymmetric seams in the part that would create localized heavy spots. Our spinner design is comprised of two sections; forward and aft. Each section is molded using continuous layers of cloth rather than spliced cloth segments.

With the spinner finished and assembled, we powered up the Airmaster propeller controller and actuated the propeller blades through their full range of motion to check clearance between the spinner and the blades.

Next, we will be attaching the engine to the firewall to complete the remaining firewall forward tasks.

If you enjoyed this video and would like to see more of this type of content, follow along as we work to engineer the fastest, longest range aircraft you can build in your garage!

More information on DarkAero can be found on our website and other social media accounts:

DarkAero 1 Aircraft - https://www.darkaero.com/aircraft
DarkAero Knowledge Base - https://www.darkaero.com/knowledge
DarkAero Apparel - https://www.darkaero.com/shop

https://www.darkaero.com
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Video Chapters

0:00 - Intro
0:38 - Spinner CAD
1:07 - Finishing the Spinner
2:51 - Why so BIG?
5:14 - Spinner Balance
8:02 - Reducing Imbalance
8:53 - Moving the Blades
10:45 - Next Steps

Thank you for watching!