Helical gears are known to provide which of the following benefits?

Helical gears are designed with teeth that are cut at an angle to the axis of rotation, which allows for multiple teeth to engage at the same time during operation. This design feature contributes significantly to smoother operation, as the gradual engagement of the teeth reduces the impact and vibration that typically occurs in gears with straight-cut teeth, such as spur gears. The angled teeth also allow for better load distribution across the gear tooth surface, further enhancing smoothness and operational efficiency.

In contrast, other options highlight attributes that are not true of helical gears. Helical gears are generally stronger than spur gears due to the way forces are transmitted through the gear teeth, and they tend to produce less noise because of the smoother interaction of the angled teeth. Additionally, helical gears operate in parallel directions rather than only in straight lines, which allows for versatility in various mechanical designs.