63-2 Tiger Cub Motorcycle

FRS 106, Michael Littman – Spring 2018

20 February 2018

February 20, 2018

Notes by Noelle Goudy

Assignment due Thursday, February 22:

This week:

  • Starting to study the science part of the book

  • Seeing how fast the motorcycle can run

  • Looking at data sheets and octane ratings

  • Thursday: learning about combustion

  • Next week: learning about aerodynamics and drag on Tuesday

Housekeeping:

  • Emily: With Jordan, cleaned up and polished the engine covers using a sandblaster, sandpaper, and a die grinder

    • A die grinder uses compressed air to make a fan blow with very high speed (and low torque) – great for polishing

  • Noelle: With Alex, disassembled the Amal carburetor and found and labeled all parts for it

  • David: Cleaned the pieces of the transmission with Alex

  • Jake: Made a tool to compress the shocks; took the shocks apart and cleaned them

  • Brendan: Had to bore a hole to take apart the shocks; sandblasted them

  • Connor: General disassembly; removed oil pump; missing ball bearing for the oil pump

    • Note to quartermasters: make sure to order new ball bearing

  • Eric: With Hannah, sandblasted different parts of the wheel; going to assemble motorcycle stands today in shop

  • Alex: With Noelle, worked on disassembling the carburetor and cataloged parts; began to clean the carburetor

  • Alex: Finishing disassembling bottom half of engine; took of main sprocket

  • Grace: Worked with Connor and Alex to disassemble the engine; will check to make sure everything is working; will go through the gasket packet to figure out if replacements are needed

  • Jordan: Worked on polishing with the polishing wheel and by hand

  • Sarah: With Ricky tested connections with a voltmeter and with a light; today, will generate sparks with old motorcycle

  • Julianne: Continued to clean top end parts; need a piston and rings

  • Ricky: With Sarah, checked electrical connections

  • Charlie: Sandblasted the two top end pieces

  • Hannah is not here

Discussion of Chapters 9 and 10:

  • Chapter 9:

    • Motorcycle References

      • Engine misfire:

        • Spark fires but no fuel is ignited

        • Misfire can cause a bang or backfire

        • Happens if the unexploded gas goes into the exhaust line

    • Content

      • Scientific Method

        • Helpful to diagnose complicated problems

        • Ends up driving Phaedrus crazy

        • Six elements:

          • Statement of problem

          • Hypotheses

          • Experiments for each hypothesis

          • Predicted results of the experiment

          • Observed results

          • Conclusions

        • Hypotheses sometimes sound dumb but are important because assumptions shouldn’t be made

        • 132: Experiment only fails if it cannot provide data either way

      • Inductive vs. Deductive reasoning

        • Inductive: making a hypothesis out of data

        • Deductive reasoning: inferring what is happening based on observations

      • Underlying Form

      • Classic vs. Romantic approach

  • Chapter 10:

    • Content

      • Characterizing Phaedrus: how did he lose his mind? Comparing Phaedrus and Einstein

        • Both study science for the stake of science – to learn – pursuit of knowledge

        • Page 111: The difference between experience and nature

          • Does nature provide the data?

        • Phaedrus is more interested in inquiry

          • The philosopher’s approach

          • Where knowledge comes from

        • Phaedrus thinks that there are infinite hypotheses and thus thinks that they can never be solved

        • Exponential growth of data and information but not of knowledge

Top Speed of the Motorcycle: 62 mph

  • K’Nex model of a Model T engine: Four stroke cycle

    • 2:1 gear ratio

    • Crack turns the connecting rod, which makes the pistons move up and down

    • The spark plug goes off when the piston is at the top

    • As the piston move up, the exhaust is blown out

    • Intake valve opens when the piston is at the bottom: air and fuel mixture enters

    • RPM: revolutions per minute of the crank

    • What is the maximum RPM of our motorcycle?

  • “Triumph-10001.pdf” – workshop instruction manual

    • We have the T20 model

    • Technical data is located at the bottom of the manual:

      • 63 mm bore (diameter of piston)

      • 64 mm stroke

      • Power output: 10 (brake) horsepower at 6000 RPM

        • 6000 rpm = 100 revolutions per second

      • Gear ratios

        • Engine sprocket: 19 (teeth)

        • Clutch sprocket: 48 (teeth)

        • Gearbox sprocket: 17 (teeth)

        • Rear wheel sprocket: 46 (teeth)

    • Clutch is going at 2375 RPM

      • Crack to clutch: 19/46 * 6000 = 2375 RPM

    • Rear wheel is going at 877 RPM (in the fourth gear)

      • Clutch to rear wheel in top gear: 17/46 * 2375 = 877 RPM = 14.6 revolutions per second

      • 14.6 revolutions per second * 6.28 ft = 91.7 feet per second

      • 91.7/66 = 1.04 * 60 mph = 62 mph

    • 48/19 * 46/17 = 6.84 (which was given as the top gear ratio)

      • Ratio of how fast the crank is turning to how fast the wheel is turning

      • Gear ratios increase as the gear goes down

  • Tiger Cub Bible

    • Page 173: Gearboxes for all of the Tiger Cub motorcycles

      • Standard, wide, close, extra-close, and ultra-close gearboxes

        • We have the standard model