Hovercraft ISSEA STEM 2018
PRIMARY CHANGES FROM PREVIOUS HOVERCRAFT EVENT:
- The EDD will be graded age appropriately, with the oldest member of the team determining the placement: Grades 6-9 or the 10-12 rubrics can be viewed here, on or before February 17th.
- The size of the craft has been changed to accept anything that fits inside of a 40 cm X 40 cm X 40 cm box.
- The width of the track will be easily adjustable and will be changed to accommodate the hovercraft.
- Disqualifications are in place for CONSTRUCTION SPECIFICATION items (b), (i) and (l) only. All other specifications that are not properly implemented will result in points off, but not disqualification.
- The track length will be exactly 1.75 meters for the hovercraft to travel. However, the goal time will be given at the time of the event, therefore teams still need to be able to adjust the speed of the vehicle.
- Teams will compete, regardless of age bracket, for the school ranking. Where two teams represent one school, the highest team score from the school be used for final ISSEA Hovercraft school ranking.
- The scoring for the competitions’ vehicle challenge has changed (detailed below).
DESCRIPTION: ISSEA competing schools may have up to two teams, consisting of one or two individuals on each team. Each team must construct a self-propelled, air-levitated vehicle according to the specifications provided in the CONSTRUCTION SPECIFICATION section below. Teams will also be assessed on their design process, data collection and analysis of data as described in separate document “ENGINEERING DESIGN DOCUMENTATION”. The EDD will have two sets of rubrics, one for teams with members less than grade 10 and the other with one or more members in grade 10 or above.
- The event will have two parts: a) The hovercraft run and b) The “Engineering Design Documentation”.
- The vehicle and any material needed (except tools) to adjust the vehicle (e.g. shims, masses, batteries, etc.) must be impounded at the start of the competition.
- The Engineering Design Documentation may be submitted at any time up until 5:00pm the day of the competition. Early submission is recommended since the forms and rubrics will be available February 17th. Coaches can give general guidance, such as clarification, or recommendations on research, but are not allowed to provide detailed help with the EDD. Help provided should be similar to that given to students who are completing a laboratory summative assessment. It is highly recommended that students post questions to the ISSEA STEM forum (link) to allow for appropriate and fair direction for students.
- The supervisor (ICS) will provide the track(s).
- Teams must wear ICS provided eye protection during set-up and testing of their vehicle.
- Vehicles may be made of any material and must meet items (b), (i) and (l) or be disqualified. All other specifications not met will result in penalties as described in the PENALTIES section.
- The length, width and height of the vehicle must fit inside a 40 cm X 40 cm width X 40 cm box.
- A dowel must be attached within 5.0 cm of the front for timing purposes and extend up at least 20 cm above the bottom of the hovercraft.
- The mass of the vehicle (including batteries and dowel) must be between 250.0 and 2000.0 grams inclusive. The goal mass of the vehicle being 2,000 grams.
- The entire vehicle, including the propeller and any propeller shielding must not extend outside of the vertical planes defined by the inside edge of the side rails of the track.
- Commercial batteries, not exceeding 9.0 V as labeled, may be used to energize the motors on the vehicle. Multiple batteries may be connected together as long as the voltage across any points do not exceed 9.0 V as calculated by their labels. The vehicle must not have any other energy sources.
- Vehicles must have no more than two motors each rotating one propeller (or “fan”).
- Propellers or fans must have a diameter of ≤ 14.0 cm
- Propellers or fans must be shielded from direct contact such that the event supervisor is not able to make contact with the propeller with a standard ¼” (0.625 cm) dowel. The supervisor must be able to verify these diameters during impound.
- Brushless motors and integrated circuits are not permitted.
- The vehicle must be levitated as it moves down the track (inadvertent contact is permitted). Competitors must demonstrate levitation by pushing the vehicle slightly down. If it then rises it is levitated.
- Vehicles must have an electric switch to permit safe starting and stopping of the motors.
- Remote control is not permitted.
- The track will consist of two iron rails, for sides, placed on top of a laminated table.
- The length will be 1.75 meters from start to finish, with additional space before and after for setting up and catching the hovercraft.
- The distance between the rails can be changed to accommodate the team’s hovercraft, with a maximum distance being 40 cm
DETAILS OF VEHICLE COMPETITION:
- Upon impound, vehicles will be inspected by the judges.
- Vehicles that do not meet the construction specifications for (b), (i) and (l) must not run until brought up to those specifications. A construction penalty will be assessed.
- Specifications c, d, e, f, g, h, k, and m, may be fixed, or not, as the team decides. Failure to meet a given specification will invoke a 5 point penalty FOR EACH specification the team cannot fix. A construction penalty of 20 points will also be assessed, but only one construction penalty for specifications not met can be assessed for all specs b through m.
- Teams will have 5 minutes to bring their vehicle up to spec and resubmit for inspection. Teams must place their vehicle back in the impound area until their team is called up.
- The length of the timed portion of the track will be 1.75 meters.
- The target time will be between 10.0 and 45.0 s.
- The event supervisor will announce the exact time, for all teams, after the final impound.
- Teams will be called up by a random drawing.
- Once called up, competitors will have a total of 8 minutes to orient, adjust or repair their vehicle(s), and make two successful or five failed runs.
- Competitors must place their vehicle on the track directly before the start line. They must place an object in front of their vehicle to keep it from moving. Prior to starting a run, and without actually turning on the motor, teams must demonstrate a safe starting and ending process.
- When ready, competitors may turn on their motors and indicate that their vehicle is ready.
- Competitors must not touch their vehicle after they have turned on their motors.
- The judge will give a countdown of “3.2.1, launch”. The competitors must then release their vehicle by removing the object and stepping away from the track.
- Timing must start when the dowel crosses the start line and stop when it crosses the finish line. (If no dowel has been attached, timing will be manual and begin when the object is removed.
- A photogate will be used for more precise timing and at least one backup manual timer will also be used.
- Time is recorded in seconds to the precision of the device
- A run will count as long as it is started before the 8-minute period elapsed.
- If a vehicle fails to move after 3 seconds, or moves only a part of the way down the track, competitors must be allowed to restart their vehicle without penalty up to four times within the 8-minute window or until two successful runs have been completed.
- Additional successful runs are not allowed.
- If during a run any part of the vehicle falls off, the run must be counted as a failed run and the team will be allowed to repair and restart their vehicle.
- Teams filing an appeal, regarding judgements made for specifications, must leave their vehicle(s) and track in the competition area until the matter is resolved to the satisfaction of the majority of ISSEAA coaches present in the room, prior to the start of the timed runs.
SCORING: A scoring rubric and checklist will be posted here around the end of February.
- Velocity score (VS): The vehicle moved forward the full length of the track (1.75 meters) on one or more trials = 10 points; the vehicle moved forward between 1.00 and 1.74 meters (inclusive) on one or more trials = 6 points; the vehicle moved forward between 0.2 and 0.99 meters (inclusive) = 4 points. The vehicle moved forward less than 0.2 meters = 0.
- Uplift score (US): The design clearly lifts the vehicle sufficiently to allow it to hover = 5 points; The design may provide some lift, but not enough to work as expected as a hovercraft = 2 points; There is no lift observed on any corner or area of the hovercraft = 0 points.
- Mass Ratio (MR) = mass of vehicle / mass of the heaviest successful vehicle. Note: Successful means the vehicle met all specs before launch, ran two runs and had maximum points on the VS and US scores. The maximum MR is 1.
- Time Score (TS) = (1-(abs (run time – target time) / target time)) x 60 points. The smallest possible TS is 0.
- EDD Score (ES): The EDD will be worth 50 points. See additional information posted on or before the end of February for more details.
- Disqualified - failure to meet one or more of the specifications (b), (i) or (l): 0 points awarded for all values except the ES.
- Construction violation: 20 points (applied one time only, for any specs b-m)
- Not meeting specifications: 5 points for each spec not met (c, d, e, f, g, h, k, and m)
- Final Score (FS) = MR x (VS + US) + TS + ES – Penalties. The maximum possible FS is 125 points. High score wins.
- Tie Breakers: 1st – Best ES; 2nd – Best TS; 3rd – Best Mr; 4th - random coin flip.
- In relation to other ISSEA Science events, final team positions in the Hovercraft event will be given point values of a school’s best team, on the following scale: 1st=8 2nd=7 3rd=6 4th=5 5th=4 6th=3 7th=2 8th=1
- Recommended Resources: Reference and training resources can be found on the website www.soinc.org