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Gravity Vehicle - PowerPoint PPT Presentation

Gravity Vehicle. Disclaimer. This PowerPoint is based on the DRAFT rules for Gravity Vehicle 2013. The rules may have changed. The rules and parameters in the 2013 Rules Manual is the final say.

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PowerPoint Slideshow about 'Gravity Vehicle' - seoras

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Presentation Transcript

Disclaimer

This PowerPoint is based on the DRAFT rules for Gravity Vehicle 2013. The rules may have changed. The rules and parameters in the 2013 Rules Manual is the final say.

Goal: Construct a gravity powered vehicle and ramp to move the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Two components

• Vehicle

• Ramp

Competition the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Track 5 – 10 m

• 50 cm interval regionals

• 10 cm at state

• 1 cm at nationals

• 50 cm wide x 75 cm deep x 200.0 cm high rectangular start box

• Start Dot at center of box

• Finish Dot perpendicular

Scoring the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Four components – Low Score Wins

• Distance Score

• Distance from the fixed point to the Target Point in millimeters. This is a point-to-point measurement.

• Time Score

• 25 * (Run Time).

• Predicted Time Score

• 50*(Predicted Time-Travel Time)

• Height Score – NEW THIS YEAR

• 400* Vehicle Height in cm/ (300 cm – Vehicle Height in cm)

Construction rules the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Vehicle

• Total mass must not exceed 1.500 kg.

• Bent paperclip as a fixed point (measurement point) on either the leftmost or the rightmost edge/face of vehicle between front and rear axles extending down to within 1.0 cm of track surface

• Only wheels contact floor

• Automated braking mechanism

• Ramp

• With vehicle loaded fit within 50 cm wide x 75 cm deep x 200 cm high box

• Release mechanism activated by unsharpened #2 pencil

General tips the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Potential energy (u) = mgh

• Maximize mass and height – maximize energy

• Get fewer points

• Minimize friction for speed

Vehicle Construction the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Major components

• Chassis

• Wheels

• Braking mechanism

• Axles

• Bearings

Chassis the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Stiffness critical

• Pay attention to joints

• Carbon Rods (from arrows)

• Wood

• Good place to add weight

• Design with braking mechanism in mind

• Steering

Wheels the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

Park-flyer style

Aluminum hubbed MPI wheels

• Thinner better for speed

• More difficult to mount

• Difficult to align

• CD’s useful

• Require special adapters for mounting

• Rubber bands/balloons for traction

Braking Mechanism the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Threaded rod and wing nut (or tapped block)

Axles the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Critical Qualities

• Stiffness, weight, ability to hold wheels/braking mechanism

• Carbon Fiber Rods (From Arrows)

• Smooth, light, stiff

• Easy to find, cheap, braking mechanisms, heavy

• Difficult to find, light, weak

• Expensive (order online), stiff!, light

Bearings the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Simple or complicated

• Tubes

• Easy, cheap, use graphite, functional

• Ball bearings

• Reduce friction drastically, can get expensive

• Ceramic hybrid best if willing to spend

• May require some breaking in

Ramp the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Straight

• Much easier to construct

• Easier to transport

• Not as efficient,

• floor/ramp interface issues

• Curved

• Delivers energy much better

• Winning team at Nationals will have one

• Interesting math problem

• http://en.wikipedia.org/wiki/Brachistochrone_curve

Ramp materials the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Frame

• PVC pipes

• Easy disassembly

• Difficult to make curved ramp

• Plywood/other wood

• Heavy, difficult transportation

• Surface

• Particleboard, Masonite, others?

• Lots of Skateboard ramp references online

Sources for more obscure materials the vehicle down a track as quickly, as accurately and as close to their predicted time as possible.

• Wheels

• R/C plane wheels, MPI www.maxxprod.com/mpi/mpi-29.html, CD’s

• Bearings

• www.bocabearings.com , online, hobby shops, etc

• Carbon fiber

• Arrows, hobby shops, etc

• Titanium

• Amazon, smallparts.com, etc

• Balsa

• www.lonestar-balsa.com, hobby shops, etc