Activity 3: Optimize the blades

Sometimes the output of fans can be optimized by decreasing the number of blades and increasing the surface area of the remaining blades. In this activity you

Edit the Circular Pattern feature in the Timeline, to decrease the number of blades
Roll back the Timeline and extend the blade design to increase the size of the blades
Remove the sharp edges of the blades where they meet the hub, by extending the edges further into the hub
Check the Properties dialog and confirm that the surface area of the blades meets expectations.

Fan hub with blade sketches (left), and fan hub with blades (right)

Prerequisites

Activity 2 is complete.

Steps

Reduce the number of blades around the hub from 8 to 5.
1. In the Timeline at the bottom of the canvas, right-click the last entry, Circular Pattern, and select Edit Feature.
2. In the Edit Feature dialog, change the Quantity from 8 to 5.
3. Click OK to apply the tool and close the dialog.
Extend the outer perimeter of the blades by 20 mm.
1. In the Browser, expand Bodies.
2. Click next to Body11 to make the spline sketch visible.
3. Roll the Timeline back before the Thicken tool, so only the original blade is visible.
4. Click (Design workspace > Surface tab > Modify panel > Extend) to open the Extend dialog.
5. In the Extend dialog, set the Distance to 20 mm and the Extend Type to Natural.
6. Click OK to apply the tool and close the dialog.
7. Roll the Timeline to the end to propagate the change across all 5 blades.
Extend the ends of the blades inwards by 10 mm near the hub, to remove the sharp edges.
1. Roll the Timeline back before the Thicken tool, so only the original blade is visible.
2. In the Browser, click next to Body2 to hide the fan hub.
3. Click (Design workspace > Surface tab > Modify panel > Extend) to open the Extend dialog.
4. Hold `Ctrl` (Windows) or `Command` (MacOS) and select the three straight edges at the end of the blade, as the Edge.
5. In the Extend dialog, set the Distance to 10 mm and the Extend Type to Natural.
6. Roll to the end of the Timeline and in the Browser, click next to Body2 to show the fan hub.
Check the surface area of a blade body to confirm it measures close to 3.854E+04 mm^2.
1. In the Browser, in the Bodies folder, right-click on a blade body and select Properties from the drop-down menu.
2. In the Properties dialog, check the Area, and confirm it measures close to 3.854E+04 mm^2.
  If the surface area is not close to 3.854E+04 mm^2, check that the surface body that created the blade was extend and trimmed properly. There was a single trim operation and two extend operations.
3. Click OK to close the Properties dialog.