importantly, nearly double distance consistency. Darts with rotation take an expected ballistic trajectory to the ground while darts without rotation sometimes take a greater-than-ballistic trajectory or travel much farther but veer drastically off target. Conclusion This group set out to improve a soft projectile launcher by mechanically imparting torque on the rounds. This goal is accomplished. This group recommends wheels set at 4 degree angles each (8 degrees total) and a wheel distance spacing of 0.35 in. The angled configuration increased the average shot distance by 4.6 ft. (+14%) and decreased the standard deviation 2.3 ft. (-40%). The most surprising result is that darts with higher rotational speeds are less able to self-correct due to centerline misalignments. Thus, lower rotational speeds (less than 1500 RPM) are desired when torqueing Nerf darts. Future Work This group has several recommendations for future work. This group used imprecise machining tools and assembly because of the rapid iteration required. However, with the above recommendations, a precise design could be machined and built. This should alleviate centerline issues. Nerf darts tend to wear quickly. They lose their rigidity quickly because they are made out of foam. The less rigid darts always performed worse (fishtailed more often) than their rigid counterparts. Further study is needed to identify a way to compensate for dart imperfections. The final design this group built is still a prototype and could not be easily integrated into an existing SPL. Future groups could look into minimizing the design and integrating it into the front of an existing SPL. Appendices Appendix A. Highspeed (2000fps) Soft Projectile Launcher Angle Test, 0 Degrees per Wheel Full video: /0deg.avi or Fig. 20. Frame 599
importantly, nearly double distance consistency. Darts with rotation take an expected ballistic trajectory to the ground while darts without rotation sometimes take a greater-than-ballistic trajectory or travel much farther but veer drastically off target. Conclusion This group set out to improve a soft projectile launcher by mechanically imparting torque on the rounds. This goal is accomplished. This group recommends wheels set at 4 degree angles each (8 degrees total) and a wheel distance spacing of 0.35 in. The angled configuration increased the average shot distance by 4.6 ft. (+14%) and decreased the standard deviation 2.3 ft. (-40%). The most surprising result is that darts with higher rotational speeds are less able to self-correct due to centerline misalignments. Thus, lower rotational speeds (less than 1500 RPM) are desired when torqueing Nerf darts. Future Work This group has several recommendations for future work. This group used imprecise machining tools and assembly because of the rapid iteration required. However, with the above recommendations, a precise design could be machined and built. This should alleviate centerline issues. Nerf darts tend to wear quickly. They lose their rigidity quickly because they are made out of foam. The less rigid darts always performed worse (fishtailed more often) than their rigid counterparts. Further study is needed to identify a way to compensate for dart imperfections. The final design this group built is still a prototype and could not be easily integrated into an existing SPL. Future groups could look into minimizing the design and integrating it into the front of an existing SPL. Appendices Appendix A. Highspeed (2000fps) Soft Projectile Launcher Angle Test, 0 Degrees per Wheel Full video: /0deg.avi or Fig. 20. Frame 599