Design of a snowbike

Slide 1: Design of a Snow Bike

Slide 2: Initial Plan • Build a water bike • Able to float and safely propel a person on the water • Scratched the idea, already in commercial production www. Shuttlebike.com Seacycle or Water bike www.Nauticleniche.com

Slide 3: Evolution of the Plan • Work with a bike or some form of human power. • Researched Snow bikes • No cross country bikes currently in production www.winterxbike.com

Slide 4: Why a Snow Bike? • No cross country human powered snow vehicles currently in production • Cross country skis are the only competition • Bike enthusiasts will not have to put expensive bikes in storage over the winter months

Slide 5: Design Requirements • Gain traction in moderate to deep snow • Hold up to a 220lb person • Attach to a standard stiff back mountain bike • Not fail in cold weather • Made affordable using some off the shelf parts

Slide 6: Speed in the Snow HP needed to maintain Velocity on flat (varying efficiency) 0.900 0.800 0.700 0.600 0.500 HP 0.400 HP needed @ 100% efficiency (no incline) 0.300 90% efficiency 80% efficiency 0.200 70% efficiency 60% efficinecy 0.100 50% efficiency 40% efficiency 0.000 0 5 10 15 20 25 30 35 40 Velocity (ft/s)

Slide 7: Power needed to maintain a velocity @ 100% efficiency (varying inclines) 3.500 3.000 2.500 HP needed @ 100% efficiency (no incline) 5 degree incline 2.000 10 degree incline HP 15 degree incline 1.500 20 degree incline 30 degree incline 40 degree incline 1.000 0.500 0.000 0 5 10 15 20 25 30 35 40 Velocity (ft/s) Data obtained from: Bicycling Science, by Frank Rowland Whitt

Slide 8: Stability in the Snow • Gyroscopic motion does not contribute • Centripetal motion gives inline vehicles the ability to lean without falling over • Constant corrections account for Stability • Trailing wheel is more stable • Shimmy effect due to joint imperfections

Slide 9: Surface Area Estimations • Should compare to snowshoe or snowmobile surface area • Large snowshoe, approx. 1psi on snow www.atlassnowshoes.com • Average snowmobile, .5 psi on snow • Bike + Human weight = 260lbs (max.) • Need between 260 and 520 in2 surface area www.ski-doo.com

Slide 10: Concepts Steering Drive 2 Skis Dual drive wheels (Tricycle) Large Board Paddle wheel

Slide 11: Final Design Concept Ski Steering Track Drive

Slide 12: Connection Points Aluminum clamps attach Extended Rear wheel permanently to frame hub will hold sprockets on the outside of the track

Slide 13: Key off the shelf components • Track from Arctic Cat ZR120 • ZR120 drive sprockets • ZR120 idler wheels • Snow lubricates drive gears and sliders • Plastic gears are light weight $250 $90 $30

Slide 14: Prototype Design • Use to test what the surface area of the drive system needs to be • Test a concept

Slide 15: Future Goals • Design and build a track system using some off the shelf parts • Design and build a ski steering system • Test in varying snow conditions

Slide 16: Acknowledgements • Prof. Keat • All Seasons Equipment inc. 60 Freeman’s Bridge rd. Scotia • Freeman’s Bridge Sports inc. 38 Freeman’s Bridge rd. Scotia • Jim Howard and Roland in the Machine Shop

Slide 17: Questions ?