Boomilever
Division: B & C – Middle & High School
NC Essential Standards Alignment: Grade 6, 7, and 8: Goals 1 and 2; High School Physics 7.P.1, 7.P.2, Phy.1.1, Phy.1.2, Phy.1.3, PSc.1.1, PSc.1.2
Description:
Teams will design and build a cantilevered beam or truss structure that extends from a vertical Testing Wall and supports a load at a specified distance from the Testing Wall. The structure must meet the requirements specified in the rules to achieve the highest score, which is a combination of structural efficiency and Load Scored Bonus.
Materials:
Only one structure is to be tested and must be built prior to competition. Protective eyewear with the ANSI marking Z87+ must be worn during competition. Competitors must be prepared to answer questions regarding the design, construction, and operation of their device. Test Apparatus will be supplied by the Event Supervisor.
FAQs:
9/16/25: Total width of the structure? I know it has to accommodate the 5cm x 5cm block, and on the first page is says “no more than 2 1/2 cm horizontally from either side of a perpendicular line…” Is this referring to the total width of the structure or just the testing block? I see total length of 40 to 45 cm.
For Division B, to be considered Tier 1 (best rankings possible), the maximum width of the structure where it bears against the Testing Wall is 8 cm. It is recommended that the end of the structure supporting the Loading Block is 5 cm or narrower (so long as the Loading Assembly can fit through the structure.)
Scoring:
High score wins. Scoring for this event is based on efficiency.
(Load supported + load score bonus)/Mass of Boomilever
Boomilevers that fail to meet one or more of the requirements will be ranked in a 2nd tier beneath those that do meet requirements. Boomilevers that cannot be tested at all will be ranked in a tier below those that can be tested. Ties will be broken by accuracy of estimated loaded supported to the actual load supported and whichever boomilever is lightest.
Common Mistakes:
The goal is not to build the strongest boomilever, it is to build the most efficient boomilever, so it has to be strong, but light.
Recommendations:
Video to show you how to put your breaker back together if you bought one from NCSO.
Event Resources:
Instructional Video for Building a PVC Breaker
Specs for Building a PVC Breaker
Boomilever Test Assembly Dimensions & Instructions
Media:
Be careful when constructing your device that it is level. If the base or any part of the tower is leaning or crooked, it will lean even more as weight is applied and potentially tip over before it breaks, as this one does.The process of placing your tower on the platform, threading the chain through, hanging the bucket, and how to load the sand. This is the PVC “breaker” used throughout NC.A tower supports 15 kg before breaking. This or a very similar apparatus is the sand loading device (breaker) used at every NC regional and state tournament. A lever on the back releases sand at a rate of the competitor’s choosing, which flows down a chute into the 5 gallon bucket. The bucket handle has been replaced with a rope, so the bucket will self- center and all the weight is always in line with the chain.Instructional video for how to glue balsa for your tower and what kind of glue to use.How to attach the sides of your tower base at the proper angle.Simply placing your tower diagonally across the platform opening reduces the length of the sides needed, thus reducing the tower weight and increasing your structural efficiency.