Hovercraft b & c 2017

Event Overview 2 part event: Make an air levitated vehicle which can run down a track. Take a test on classic mechanics and related topics.

Requirements Impound and eye protection are both required for vehicle portion. Competitors may bring reference materials in a ring binder. Calculators are allowed.

Impound The vehicle must be placed in a box (vehicle and box must be labeled with the team name and tournament specific team number) and must be impounded. Tools and supplies do not need to be impounded.

At the competition Teams will all start the written test. Teams will be called up 1 or 2 at a time for vehicle testing, and then can return to their written test. For larger competitions, multiple tracks may be used.

The Track Supervisors must provide: Two 8-foot beams, 30mm width and height min. (metal framing studs are recommended) Cushioned barrier (bubble wrap, etc.) Wood block (to hold car back until start) Table or counter top (standard 8 ft. table) Timing system (photogates recommended) Track length (start to stop line) must be 135cm for B and 100-195cm for C division.

The Track

The Track

The Vehicle Length between 15 and 30cm. Width less than 19.5cm . Height excluding dowel must be less than 20cm. Up to 2 motors and 2 propellers. Propellers must be shielded (1/4 inch dowel test) 9 volts maximum (make sure battery labels are visible) Wooden dowel (¼ inch or larger) within 5cm of front. Height from table 30-35cm. Vehicle must levitate

Motors Hovercraft 4.i. should read: "Brushless motors and integrated circuits are not permitted, unless they are an integral part of and are imbedded into a commercially available electronic or computer cooling fan." (9/12/16) Switches are required to ensure safety.

Vehicle testing Supervisors will announce target time (5-25s) and track length after impound. Teams will have 8 minutes total to adjust their vehicle and make 2 successful or 5 failed runs. Teams must demonstrate stopping procedure before the first run. Teams must place their vehicle at starting line, start the motor and count down. Supervisors will remove the block. Teams must not touch the vehicle until it passes the finish line, or until instructed.

The Written Test The competition must consist of at least five questions from each of the following areas: Newton’s Laws of Motion: inertia, force, impulse, action-reaction Kinematics: projectile velocity, speed, acceleration, position Kinetic energy: calculation, momentum, non-relativistic Air cushioned vehicles and applications: history, design, capabilities Fluid mechanics (Division C only): density, buoyancy, viscosity, Bernoulli’s principle, Pascal’s law

The Written Test cont. Unless otherwise requested, answers must be in metric units with appropriate significant figures. Teams must be given a minimum of 20 minutes to complete a written test. Questions may be multiple choice, true-false, completion, or calculation problems.

Test Practice Resources Problems will range from regents level physics to first semester college physics. Similar problems can be found in test banks from regents, AP, SAT physics.

Helpful Websites http://www.aplusphysics.com/courses/honors/honors_physics.html http://www.nysedregents.org/physics/ http://www.sparknotes.com/testprep/books/sat2/physics/ https://secure-media.collegeboard.org/digitalServices/pdf/ap/ap-physics-c-mechanics-practice-exam-2012.pdf http://www.solvephysics.com/

Scoring The test is 50% of the score. The mass score is 25(mass of vehicle/mass of heaviest successful vehicle). This is 25% of the score. Time score is (1-(abs (run time – target time) / run time)) x 25 points. This is the final 25%. The better time score of 2 runs counts. As always, there are penalties for violations of construction and competition rules.

Penalties Vehicles with construction violations at the time of a run score a failed run! (II-q.) Teams with no successful runs or DQ for unsafe operation receive mass and time scores of 0. Construction violations repaired during timed test result in (.7) multiplier for mass score. Competition violations during a successful run result in a (.9) multiplier for that run time.

Make sure your vehicle meets all specifications before impounding it.

Tie Breakers 1st - Best ES 2nd - Best MS 3rd – Best other successful run TS 4th - specific test questions

Coaching tips Students should read the rules many times. Let students try different designs: single propeller, 2 propellers, etc. Pink foam insulation is good for making prototypes. Help students organize their binders by topic. Run a mock competition with time constraints. Practice on different tables/surfaces. Try running from the other end (in case the table is not level)

Conclusion Have fun! This is a great event! Much of the content of this presentation was taken from the Division C Rules Manual 2017. Rules are subject to clarification or revision. Please stay posted at https://www.soinc.org/ Have fun! This is a great event!