λ+Design

=Design=

The rocket was designed to be as lightweight as possible using only materials I found within ten feet of my workbench, while still being strong enough to survive multiple launches without deformation. While building, we used the free trial version of the Rocksim software to virtually model and test our rocket to confirm its aerodynamic stability. With the exception of the recovery system, I believe the design was a success.

The most unique part of our rocket design is the rigid, durable engine mount. It was made by cutting off the bell-end of a 1/2" PVC pipe such that the engine could not fit through the narrower top, eliminating the need to rely on a flimsy hook. The engine mount was intentionally made shorter than the engine length both to reduce destabilizing mass behind the fins, and in the hope that the protruding engine might deflect impact from the fins on landing. The body tube was rolled directly onto the mount and hot glued to it securely, providing rigidity to the body tube and fin mount area.

The body tube was made of 3 pieces of 8.5"x11" cardstock rolled together and secured with masking tape. The four fins were made of 2"x1.5" pieces of a cardboard box hot glued to the bottom of the body tube, directly outside the engine mount. The open edges of the fins were covered in masking tape to reduce drag. The glue joint between the body tube and the fins proved to be the weak point of our design, as the impact of landing would tear a thin layer of paper from the body tube away with the fin. However, this would not have been an issue had the recovery system fully deployed to reduce the impact force.

The nosecone consisted of two hollow pieces of Lego glued together, with a styrofoam cylinder glued inside and protruding out about 1/2" to fit inside the body tube. Part of a popsicle stick was glued into the styrofoam and attached to the shock cord with string.

Our recovery system was another innovative design feature. The shock cord was bolted to a wire, which was in turn looped around a section of skewer bisecting the body tube about 3 inches from the top. This provided two advantages: not only was it more durable than a traditional glued shock cord mount, it also kept the recovery assembly from sliding backwards under power and moving the rocket's center of gravity to an unstable position. The only shortcoming of our recovery system was the parachute itself; for reasons unknown, it failed to fully deploy despite our team utilizing several different packing methods. However, it still provided enough drag each time to limit damage to a single fin.

Overall, we were satisfied with the performance of the rocket. It proved to be very aerodynamically stable without excessively large fins, reasonably durable, and easy to repair.

Rocket statistics:

Overall Length: 11" Mass (takeoff): 110g Total Fin Area: 12 sq. in.

See Performance Projections

λ - Design - Performance Projections - Materials - Time Line  Primary Launch -  Secondary launch - Analysis - Conclusion   Lab Report