Group 5 - Nerf N-Strike Longstrike CS-6
MAE 277: Introduction to Mechanical Engineering Practices Fall 2012
The Design Team
The following four design members will be working together, using each others' strengths and weaknesses, and communicating effectively to reverse engineer the Nerf N-Strike Longstrike CS-6. The engineers working on this design team are:
Sarah Selk [Project Manager] Brianna Stewart [Director of Communication] Brian Heffernan [Technician] Bryan Krajewski [Engineer]
The Nerf N-Strike Longstrike CS-6 has taken a traditional Nerf gun and transformed it into a three foot long, thirty-five foot long range, firing Nerf machine. The Nerf gun is intended for children ages six year and older. It consists of six main components, which are shipped in seven pieces, which must first be assembled in order for the gun to be used. The user must first cock the gun backward and then forward in order to load the foam Nerf dart into the base of the gun. When the trigger is pressed, the dart is released. To discover the inner workings behind this variant design is the goal of the design team's work. "So grab your gear, steel your nerves, and prepare to 'go long!' "
The four team members of Group 5, worked together to reverse engineer a mechanical product of their choice. The design team chose the Nerf N-Strike Longstrike CS-6, a toy Nerf gun made by the Hasbro Company for children ages six years and older. The main function of this Nerf gun is to shoot a foam dart a maximum distance of 35 feet with great accuracy .
In order to reverse engineer the product, Group 5 disassembled, analyzed, and then reassembled the Nerf gun. In the disassembly process, the design team documented each step of the procedure in order to analyze the subsystems that aided in the functioning of the design of the device. The connections made between each component were also analyzed; including the physical connections, signals, mass, and energy flows. The Quick-Reload Clip is first inserted into the Main Base of the gun through human energy. The Cocking Bolt is then pulled backwards and then forwards, compressing the spring and storing potential energy in the spring. When human energy is used to pull the Trigger, the compressed spring is then released, which then causes Air Chamber 2 to slide over Air Chamber 1 creating air pressure and transferring the potential energy of the spring to kinetic energy in the piston system. The air forced through the tube pushes the dart from its place of rest and transfers the kinetic energy to the dart, forcing it to move through the tube and be shot from the gun.
From here the subsystems were broken down into their key components which were analyzed in the product analysis. During the analysis, key concerns with the component function, component form, manufacturing methods used, and component complexity were addressed as well as key global, economic, societal and environmental concerns in the manufacturing process. The design team then created a solid model in order to show the interactions of the key components of the Nerf gun. From here, they were then able focus on the engineering analysis of one key component, the spring, as well as recommend three design revisions on a subsystem level. After this thorough analysis, Group 5 was then able to reassemble the Nerf gun. After creating a detailed step by step process of the reassembly procedure and analyzing the Nerf gun, Group 5 determined the main mechanism of the gun to be the Trigger mechanism, which the group found to be a linear cam. In this mechanism, the Trigger is the cam and the Internal Spring 1 Connection is the follower. When the Trigger is pulled, Air Chamber 2 and the Internal Air Shaft Spring are released as the Internal Spring 1 Connection follows the Trigger’s inclined plane upward. This then forces air through Air Chamber 1 creating the necessary energy transfer and force to cause the dart to move. From here, the design team worked together in order to recommend three further design revisions, this time, on a system level. These revisions included a mechanism redesign to a rack and pinion, an addition of a revolving chamber, and a bow and arrow type of shooting.
Finally, the design team worked together in order to finalize all of their previously gathered information as well as give a presentation of one of their design revisions to the Nerf gun. This revision was the mechanism redesign of the Cocking Bolt mechanism of a linear cam to a rack and pinion.
Throughout the completion of the reverse engineering project of the Nerf N-Strike Longstrike CS-6, the design team was able to draw many conclusions about the engineering and influences behind the design decisions. This included considering functionality, manufacturing, aesthetics, and engineering analysis of the Nerf gun as well as its components. The life cycle of the Nerf gun also played a key role in the design as did many global, economic, societal, and environmental concerns. The design team was able to make these conclusions, about the influences of these factors on the final design, throughout the project due to detailed group analysis combined with hands-on experience throughout the project. Group 5 was a four member team that was able to work together, improve each other’s weakness, and reverse engineer the Nerf N-Strike Longstrike CS-6.
The Product Proposal
The Nerf N-Strike Longstrike CS-6 was the right product for the design team. Each member has the right skills to work together to reverse engineer this product, as well as learn about factors that influenced the design. The mechanical components, the complex concerns behind the design, and the finances all form an important role in this project. All of this, the design team has chosen to figure out about the Nerf N-Strike Longstrike CS-6.
Gate 1: Project Planning
To reverse engineer the Nerf N-Strike Longstrike CS-6 is a time consuming task, that involves many parts and an extreme attention to details. Therefore the design team outlined the entire extent of their project with a time table as well as researched an initial assessment of the Nerf N-Strike Longstrike CS-6. This was done by the team as a whole in order to ensure completion of the entire project on time as well as to the best of their abilities. This was done to ensure a fully functioning and communicating design team.
Gate 2: Product Dissection
The next step completed by this design team in their reverse engineer project was to fully dissect the Nerf N-Strike Longstrike CS-6. This process included the exact procedure taken by the team as well as an analysis of the connection between subsystems found. A brief review of the design team's functionality was also included.
Gate 3: Product Analysis
After dissecting the Nerf Longstrike CS-6 and documenting the process, a thorough engineering analysis was completed for the product. Components were classified and analyzed in order to fully understand the functioning of the Nerf gun.
Gate 4: Product Explanation
As the design team finished the analysis of the components of the Nerf N-Strike Longstrike CS-6, the next phase in their project was to reassemble the Nerf gun. As the product was returned to its original form, the design team fully analyzed the mechanism involved in the Nerf gun as well as recommended three design revisions which would increase the desirability of the Nerf gun.
Gate 5: Delivery
The final step of the design team’s reverse engineering project of the Nerf N-Strike Longstrike CS-6 was to finalize all of the work that the group completed throughout the project. The team revised all of their information as well as summarized their major findings from the project. The team completed the project as they gave a final assessment and an oral presentation.
 Hasbro. (2012). Nerf N-Strike Longstrike CS-6. Retrieved October 7, 2012, from