59 Tiger Cub Motorcycle

FRS 106, Michael Littman – Spring 2013


May 2, 2013

What we did in the lab:


The rear wheel was not spinning so it was taken apart and new spacers were put in.


Worked on the headlamp.

Bottom End:

Looked for and found two screws for the engine casing – the importance of the little things – attention to detail

Top End:

Cutting out new valve covers.


Helped with tensioning the wheels

Class Discussion on the Last Chapter (Concluding Remarks) of Shop Class:

Does failure make success more meaning?

The importance of learning from your mistakes.

Failure gives you a different perspective

Failure humbles

The author has a chip on his shoulder, a defensive tone, because the system has failed him.

If your afraid of failure, you won’t take bigger steps.

The author might lose some credibility in what he argues because of his disparaging attitude towards higher education.

Self-reliance can’t be your only doctrine because you become isolated

Don’t be completely reliant but also don’t be completely separate

April 30, 2013

Reading Assignment:

For Thursday, 5/2: read the concluding sections of Shop Class

What we did in the lab:


Worked on the wheels, got one inner tube in, and cleaned parts of the wheel assembly


By manually spinning the distributor, got a spark from the spark plug

The stator is in the engine

Ready to do wiring harness

Top end:

Helping other groups


Glenn made new tab washer

Almost everything is back on

Bottom End:

Helped out with other groups

Class Discussion on Chapters 23 to 26 of Zen:

Chapter 23:

He had unfinished business

The separation from his family – the glass door – is because of his quest for reason?

Chapter 24:

Is scientific method applicable (does it work?)?

The limitations (can only test things you can think of – infinite number of hypothesis)

A sense of quality leads you forward to the goal, making scientific method a tool

Use intuition, experience, scientific method

When confronted with a stuck screw, the traditional scientific method is useless to tell you what methods can be used and which method is the right one

You can drill it out, penetrating oil (solvent), screw extractor

The analogy: the box cars are the Classic Knowledge, the leading edge of the engine – the dynamic movement of the train – is the Romantic Knowledge, and the rail or the track on which the train travels is Quality

Chapter 25:

There is a conflict with technology because of the misunderstanding of the fact that technology is the fusion of nature and the human spirit

peace of mind produces quality work

Chapter 26:

gumption is like enthusiasm, being at the front of the train of his own awareness

Start a course on gumption – Gumptionology 101

There are two main categories: setbacks (external) and hangups (internal). There are three main types of internal gumption traps: value traps (block affective understanding), truth traps (block cognitive understanding), and muscle traps (block psychomotor behavior).

A mechanic can’t have too big an ego, because there are constantly things you don’t know, instead one needs confidance and enthusiasm

Impatience and boredom are dangerous, they cause one to make mistakes

The Japanese word mu means “no thing”, neither yes nor no, instead it indicates a non-answer that means that you are asking the wrong question

The cycle you are working on is not only the machine itself, but also yourself.


Reports on Motorcycle Progress from Last Class



Forks are no longer leaking (it was missing washer)
Worked on presentation
Put together shocks (new shocks, chromed on sides)



Hooked up wiring harness: tried to test it and was not able to get spark, John later got a spark
Should start tie wrapping wiring harness to frame today’s class



Found tan washer for rotor
Clutch all ready to go
Professor Littman cleaned up the threads
Must find the right woodruff keys

Top End:

Continued work on valve covers

Bottom End:

Helped with brakes/frame/clutch group


Class Discussion on Reading: Ch. 7+8 of Shop Class

Chapter 7: Thinking as Doing

  • Universal knowledge = learning from books
    • also learning while doing! (i.e. firefighters have a “sixth sense” that tells them when to get out of the building before it collapses)
  • learning by doing: learn from past experiences
  • writing of service manuals
    • technical writers not necessarily experienced but present false pretense of rationality
  • “The things we know best are the ones we contend with in some realm of regular practice” (163)
    • hammer means nothing unless we fiddle around with it, put it to practice
    • application to this class:
      • understanding theory/diagrams are difficult to fully comprehend until we disassembled and we could physically touch each part
  • electrical system: Ohm’s Law – V = IR 
    • physics theory of how electrical system is supposed to work v. additional resistance in wires that cannot be accounted for in theory, don’t know where this resistance comes from or how much of it there is
      • learn about resistance in wires from experience (can tell if it comes from rain v. sand based on past hands-on experience)
    • tight, dry and clean to describe electrical connections
      • tight = no jiggle between wires to avoid intermittent connection
      • dry = if they get wet (oil, especially) can interfere with electrical conductivity
      • clean = wire is oxidized
    • use different tools to fix wire problems based on environment (acquire knowledge of which tools based on past experience)
  • Chess: Novices v. Experts
    • learned tendencies, experts learn how to store recognized patterns
    • idea of tactics v. position
      • “experts learn to perceive things that are invisible to novices”
        • difference in perception, different appreciation, thus different judgement of Quality
  • knowing that v. knowing how
    • intellectual v. personal knowledge

Chapter 8: Work, Leisure, and Full Engagement

  • dichotomy between work and leisure
    • most people work to have MORE leisure, but if you work more, in reality you have less leisure (leisure defined as the absence of work)
      • are work and leisure mutually exclusive?
      • can be really engaged in, enjoy work
      • in the case of author, working motorcycles as mechanic is pleasurable (he could be wiring houses for $$$ but doesn’t do it because he does not enjoy it)
      • “wholehearted activity”: this is what one should aim for, work that is enjoyable
  • Debate: Should we work to get more leisure or work because we truly enjoy it?
    • Peace Corps
    • To do the things you want, you have to do the things you don’t want
    • Constant tradeoff between happiness and money
    • Difference between enjoyment and fulfillment
  • Rolls Royce man – lover of Rolls Royces, but has no idea where the parts come from
    • Can you really enjoy something without knowing its full function, the components, or the entirety of its operation methods?
  • If you turn a hobby into a business, you’ll hate the hobby.

Reading Assignment: 

For next Tuesday, 4/30: Chapters 23-26 (23, 24, 25, 26)

For next Thursday, 5/2: read to the end of Shop Class


Reports on Motorcycle Progress from Last Class


Put on brake shoes
Truing of the wheels was completed
Repaired suspension fork before putting front end on
Put forks back together
Cleaned, collected balls and placed into races (the races used were new and taken from extra frame because original races were pitted)
Put together ball bearings
Worked on presentation


Worked on presentation
Made measurements for system
Tested battery and brake light – both are in good condition
 Note: we have a 6V battery – nice brake light, but it’s 12 V (so it’s dim), so use old bulb


Worked on a computation
Helped with frame setup
Prepared the engine so clutch can be put on next
Searched for engine sprocket and rotor
Recommended test for today: see if there’s enough magnetic field to generate good spark by testing the magnetism between a big screwdriver and our rotor
Tried to get side plate on – didn’t have right screws for it.

Top End:

Worked on valve covers, designing valve covers
Ran through tutorial on manufacturing parts

Bottom End:

Put on shifter
Tested all the gears
Verified that transmission was put together properly
All systems confirmed to be good on engine


Class Discussion on Reading: Chapter 19-22 of Zen

Chapter 19:

  • Phaedrus’ dilemma: metaphor of bull
  • Conclusion: Quality is the overarching source of objectivity and subjectivity (is this argument a cop-out? Or is it the only way to reconcile Phaedrus’ views on Quality? Is Quality indeed larger than objectivity and subjectivity both?)
    • subjectivity v. objectivity
  • Scientific materialism v. classical formalism
  • Real = detectable by instruments/technical means
  • Quality cannot be detected or touched – does this make Quality not real?
  • mind (emotional, romantic) v. matter (tangible, classical)
  • Quality as the 3rd component of mind and matter discussion
  • quality as an event, not an object
    • reaching the summit of the mountain as event – coincidentally occurs when he arrives at this epiphany!

Chapter 20:

  • analogues(=past experiences) make up our decision-making/interpretation of Quality
    • Kant’s idea of au priori
  • Quality as equivocation of reality
  • Philosophical proofs can be both true and logically consistent; doesn’t mean they’re right
  • “Quality is the continuing stimulus which our environment puts upon us to create the world in which we live. All of it. Every last bit of it.”
  • quality as a continuum – changes with the mainstream
  • short term v. long term Quality
    • Debate: Did we improve the Quality of the motorcycle?
      • short term: painting, improved aesthetics, powder-coating
      • long term: longevity, conducive of maintenance, proper functioning
  • classic v. romantic quality
    • classic = concerned with more than just present, takes into account previous awareness and previous history and looks to plans for future
    • romantic = just concerned with here and now, instantaneous impressions, immediate perceptions and appeal

Chapter 21:

  • “Quality is the Buddha” – rational unification of human experiences that are allegedly disunified (Art, Science, and Religion)
    • Quality at center of it all
  • Focus on how Quality relates to Science
    • Science = typically black or white
      • unlike art, which is usually more of a gray field – more room for subjectivity
        • debate about whether or not art serves an objective/mechanical purpose
          • art for art’s sake or art with unified/decipherable message
    • Can develop metric/standards by which to measure quality
    • Quality most easily assigned to scientific objects/processes that work, things that have been proven/experimented with and verified

Chapter 22:

  • Phaedrus works top-down; Poincare works in opposite direction
    • Poincare starts with simple ideas and works his way up to Phaedrus’ point
  • How do we know which one of the geometries is right?
  • Hierarchy of facts is based on convenience
    • mathematicians may not care about utilitarian aspect
  • Math is not just about applying the rules (less so than in science)
    • “true work of the inventor consists in choosing among these combinations so as to eliminate the useless ones, or rather to avoid the trouble of making them, and the rules that must guide the choice are extremely fine and delicate”
  • Take only the facts that you need, and are thus useful

Reading Assignment: 

For THIS Thursday, 4/25: CH. 7+8 in Shop Class

For next Tuesday, 4/30: Chapters 23-26 (23, 24, 25, 26)

For NEXT Thursday, 5/2: read to the end of Shop Class

Tuesday, April 15

Reports from last week’s work:

Professor Littman told us:

Glenn pressed in steering column.

We are going to put the motorcycle on the center stand this class and we’ll almost be ready to start putting parts back on the bike

We realized that the rear Wheel has two sides. Joe and Professor Littman had to re-do all of the spokes.


Linked up all of the components to the electrical system

They re-did some of the simulations and everything looked like it was working well

Top End:

Worked on their presenation for the day

Bottom End:

Finished putting the entire bottom end into the engine

They sealed the first half of the covers

They’re ready to put the final touches on the engine


Worked on presentation

Need to get a new clutch cable

Frame, Forks, and Wheels:

Worked on putting the rear wheel together.

We need to compare the overhangs of the wheels for our bike against the overhangs of the wheels for the old bikes

We discussed chapters 16-18 in Zen:

  •          How do grades affect a student’s work ethic? Are they positive or negative?
  •          “We’re all here because we learned to play the system” – school is a game that must be mastered
  •          Even if grades are not conducive to education, it’s a little idealistic to just do away with them all together and expect students to remain motivated

Pr Professors vs. Teachers. Does it mean to be an instructor in college versus an instructor in high school?

  •          Would students work without grades as motivators?
  •          A very interesting discussion about Princeton’s policy of grade deflation
  •          Life is a mountain: is it about the destination or the journey?
  •          Have we been improving the quality of the motorcycle? Yes. We’re improving the way it will run, we’re adding materials and components that weren’t there before, we’re fixing issues.


For Tuesday (April 23rd): the four next chapters in Zen (chapters 19, 20, 21, and 22)

For Thursdsay (April 25th): the next chapter in Soul Craft

Tuesday, April 9


4/16 – Zen chap. 16-18

4/18 – Shop Class chap. 7

4/23 – Zen chap. 19-22

4/30 – Zen chap. 23-26


Recap of Last Class (4/4)

Wheel/Frame – worked on presentation, wet-sanded battery box to make it even and flat for priming and painting, everything got powder coated, primed for painting

Clutch – cleaned parts, found missing parts, put the clutch together (assembled all plates)

Electrical – assembled backup engine and frames to measure length for wires for the wiring harness

Top End – put together the valve spring mechanism but have to take it apart due to an error in assembly

Bottom End – cleaned parts, found missing parts (small washers, etc.), ready to assemble, make sure channel for oil is clear


Discussion of Zen Chapter 15

-Narrator is frustrated with rhetoric, said that rhetoric isn’t real because it didn’t have set rules, was arbitrary, rules added on post-hoc, and these rules can’t be followed/can’t imitate other writer’s style

-How John sees motorcycle maintenance is how narrator sees rhetoric

-Quality: narrator can’t define it, frustrated with what it is/what people think it is, capitalized because he wants to define it (like other abstract ideas, i.e. Truth)

-What makes one thing a piece of junk and another elegant?

-Form and function: structural integrity vs design, depends on if you’re talking to an architect or an engineer

-Quality for a motorcycle: how economic is it, how stable is it, cost of material

-There are functional qualities in writing: being succinct, omit needless words

-Largely depends on who is interpreting it and what its purpose is, if everyone has one definition of Quality, then only the motorcycle with the best quality would be sold, there would be no need for all the different types of bikes

-Some part of Quality is artistic, which is subjective, depends on the emotional response of the viewer

-Quality: standard of something measured against something similar (Oxford definition), can only exist in relation to something else, but be careful of definitions- can be defined with examples, not necessarily conclusive

-The discussion of Quality sets the stage for part III for the book

Thursday, April 11

Recap of Last Class (4/9)

Top End – the engine head is ready to go

Wheel – put bolts into front wheel and tightened it, pressed in bearings

Frame – primed

Electrical: got a wiring harness, scraped off the paint where the circuit needs to be grounded to the bike frame

**Make sure to get ground to engine casing, scrape off paint of the engine mounts, so electricity can flow

**Make sure the front and back frame are connected electrically

Clutch – helped other groups

Bottom End – put engine together, stopped at oil pump


Discussion of Shop Class Chapter 6

Intellectual Jobs

-Felt obligated to get an intellectual job after having gotten a masters degree

-But working at a think tank was actually intellectually damaging (which is worse than being a mechanic/electrician who gets physically injured)

-Focus on efficiency, churning out bad quality abstracts, only wants profits

-But quality can be compromised in the motorcycle shop as well

-Author not giving credit to the fact that other people might not think like him, maybe it’s just him trying to promote a particular point of view

-Other side of argument: rewarding intellectual work and drone-like mechanics

-Entry-level work: not very intellectual, mindless tasks, only when you get higher up do you get to do more intellectual things

-What he says is not necessarily wrong, he’s just generalizing his one experience


-Managers are important, keep the place running smoothly, and can also mess things up

-There are skills associated with being a good manager

-Author under-emphasizing satisfying the recipient of produced goods, which are people

-Inter-personal relationships are more important than they have ever been


-Most jobs require degrees now

-Autmissing the things that being in college teaches you, like organizational skills, how to manage your time…which prepares you for the real world, teaches DISCIPLINE, ability to do work, to be given an assignment and complete it

-Employers don’t look at grades, look at the fact that the person had gone through the process

-University provides a filter for the job world, credential part of it, even if it doesn’t necessarily go on to the knowledge side

Teamwork vs Crew

-Team: you don’t know who’s responsible for the blame, roles different, team dynamic is very different depending on how many people/who is on the team

-Crew: has worth independent of the others

-Working for a big or small company has different dynamics


-Corporate world: you don’t know who’s going to be promoted

-Apprenticeship: clear hierarchy of knowledge, is how you get ahead in the trade world

April 4th Thursday

Recap of last week

-Frame/Forks/Wheels: Sanding and priming the battery box and oil tank.

-Electrical: Figuring out the circuit of the bike. Model circuit. Need to start laying out the wires and start making connectors.

-Clutch: Taking exploded pictures of parts to get ready to set up the bike. Cleaning up parts.

-Bottom End: Finished inventory. Laying everything out and finding missing parts. Glen replaced one of the gears.

-Top End: Exploded view of parts. Missing two small springs.


Prof. Martinelli

Current Work: Interest in aerodynamics and fluid flows. Did a lot of sailing. Specializes in external aerodynamics. Deciding shapes that minimize drag. Optimal aerodynamic performance: Wings. Key is to achieve performance goals, not to delve into the specific physics and theory. Went from unsophisticated pen and paper models and formulas to much more powerful computer models that can perform complex calculations of a series of non-linear partial differential equations.

Initial assumption was that velocity flow was a potential field.  Aerodynamics and Electromagnetism very similar in some regards.

Involved in the development of numerical methods and their application to computational science with regard to aero and fluid dynamics. Different bottlenecks: e.g. not enough knowledge on the physics, or not enough knowledge on the numerical methods, inability to put a system together.

Worked with blended wing body, large twin engine. E.g. Beechcraft, Embraer-180. Also for boats. America’s Cup.


Downforces on a car: Front Wing, Rear Wing, Diffuser on the bottom of the car. Diffuser uses the bottom of the car to form a Venturi with the ground. The Diffuser is mainly the design of the curve of the exit at the back of the car bottom.

Venturi: Pipe with area changes. Area of pipe decreases and then expands. Area of intake different from area at throat.

Mach number: Relation between the velocity and the speed of sound.

When Mach number < 0.28 , flow is separated from the thermodynamics.

When Mach number 0.3< M < 0.5, flow is affected by thermodynamics.

When Mach number 0.5< M < 0.9, flow is transonic

When M > 1, supersonic.

Mass flow rate has to remain constant (when density is constant). When the velocity of the fluid is faster, the pressure is lower beneath the car and therefore the car is pulled down.

Same applies for airplane wings. Airflow faster at top of wing (depending on angle of attack) and therefore suction on the top of the wing generates lift.

Carburetor works the same way. Venturi system creates area of low pressure through which fuel is injected.

Drafting: When a fluid flows over a body, it is most desirable for the streamlines to be completely reflected and for the pressure to return to the same after the object passes through, and there is minimum drag. However, streamlines are disturbed at the back end of the flow and there is significant drag.  Dimples in golf balls allow streamlines to flow better and decrease form drag, but increase viscosity drag. When drafting, the velocity of the air after the first car is very low, so the second car enjoys less resistance.

For a truck, the drag region is about the same as one truck length.

For bikes, the resistance is decreased for those in the pack compared to the leading riders.

Tips of airplanes (or birds’ wings) have a strong tip vortex on the tips of the wings. These create a drag on the airplane.  When birds or planes are in formation, the tip vortices cancel each other out as they are spinning the opposite ways. Winglets also reduce vortex tip drag.

The way that motorcycle riders position themselves is also to reduce form drag.

Choked flow: In the intake flow the air is colder, and the speed of sound is less. The intake pressure differential is also much less than the exhaust pressure differential. Therefore the intake valve tends to be much larger.

Tuesday April 2nd

Recap of last week

Frame Group used primer on the gas tank and wheel fenders

Model T: Wheel brake can be adjusted to half or fully loosened. When full, a spring puts the leftmost pedal automatically at high gear.


Recap of Prof. Ju’s visit:

-Relationship can be established between temperature chance and work done (Thermodynamics)

-The higher the compression and larger the volume of the combustion chamber, the larger the decrease in temperature as a piston moves down and the gas expands, and therefore higher efficiency.

v = sqrt(3kT/m)

Thermodynamic Efficiency = (kTH – kTc) / kTH

-We learned the difference of leaded and unleaded fuels, and the different numbers for different fuels. The higher the number, the higher the octane number. Lead, alcohol and other additives used to react with the smaller hydrocarbons, so that only larger, less reactive ones remained.

-Diesel engines use self-ignition

-Significance of nitrus: Higher oxygen percentage than in air (21%).

-Compression ratios, bad side: Harder to start, higher emissions, higher pressures. Require stronger materials as stress on materials stronger.

Hybrids- Two different types of hybrids. Volt vs Prius. Volt uses a battery first and then the gasoline engine after battery runs out. This means that both the battery/electrical drive system and the gas engine must be high quality. On the Prius the gasoline engine charges the battery, so the batteries don’t necessarily have to be as good.

Modern fuel injection reduces knocking as the fuel is not drawn in on the compression stroke, but rather can be controlled and timed to come in at the right time.

Turbo/Superchargers – Compresses the air that comes into the combustion chamber, so that it’s higher pressure and preheated. Turbocharger uses exhaust gases to drive the compression.

Questions for Prof. Martinelli

Computational Fluid Mechanics. Boeing Fellow.

-Drafting. Slipstream.

-How close the front of the car is to the ground.

-Downforces. Rear wings. How it can improve traction on the rear wheels.

-How fast can a car go?

-Boundary layer for aerodynamics.

-Solar powered airplane

-Jets on a carburetor. At high altitude the engine runs lean because of not enough air. So what do you do with the jets? By opening them up?


-Driver positions for drag? Drag on on a motorcycle. How to reduce it?

-Fins on the motorcycle. How many? How big? How you figure out the fin configuration.


The Art and Zen of Motorcycle Design


Chapter 12/13:

-His relationship with DeWeese: They are very different in the way they approach things. E.g. DeWeese not understanding his sense of humor. This is why Phaedrus is fond of DeWeese though, because they have different thoughts. (Karen) Often irritated with each other however. (Danny) Are fascinated with each other because they don’t understand each other(Shirley).


-Phaedrus giving up his dedication to reason. The idea of not presuming that if something is logical, that it has to be the truth (Margaret).


-Classical vs Romantic inquiry in Oriental Philosophy. He’s come to doubt means of inquiry. (Frances)


-The “Church of Reason”. (Jenny) He is fanatical about what he does. He gets fed up with the Oriental Philosophy and contradicts himself. He is very keen on the idea of the University being both a set of subjects (what is being done) and a set of objects (buildings, etc). (Danny)


-He doesn’t understand Oriental Philosophy and is extremely contradictory of himself. (Littman) He doesn’t quite respect it for what it is (Dan).


-The primary goal at a “Church of Reason” should always be truth. Too often it becomes more bureaucratic or entangled with other priorities and issues. (Jenny)


-You’re never dedicated to anything that you have complete confidence in. (Littman)


Chapter 14

-The Instruction Manual: Even though the machine might work fine, if you’re not in the right state of mind, then the machine might not do what it’s supposed to do.

-Someone who has experience and knows what they’re doing adapts as they go along instead of just blindly following instructions.

-The difference between art and science; Science is to break down, and art is to put together. To look at someone as the pieces or to look at the pieces as a whole, and the different meanings that it takes on as a result.

-Connection back to Kant. Looking at a bunch of parts with just your senses versus looking at them with knowledge, you are much more oriented and see it as a motorcycle.

-Difference between art and technology. The divorce of art from technology is completely unnatural.

-It’s often better when technology is combined with art. Both are required to achieve something both functional and aesthetically pleasing.

-The idea that science works with chunks and bits with continuity presumed. DeWeese works with continuity with chunks and bits presumed.



For Next Tuesday: Chapter 15 of Zen.

For Next Thursday: Next Chapter of Soulcraft (Chapter 6).


Brake Dynamometer

Measuring the torque speed curve for an electric motor.

Using a rope brake.

You can figure out the torque that a motor can produce, and the power it can produce, and make a measurement as a function of speed.


Pulley 2 inches in diameter.  A rope going over a spinning wheel. The torque on the wheel is equal to (T1-T2)/r

Torque-speed relationship is linear.

Power = Fv

So the Power curve is a parabola.

1 HP = 33,000 ft-lb/min

For an electric motor, the maximum power delivered to a load is at half the no-load speed.

For humans there’s a hill curve. The maximum efficiency is around one revolution per second.

Thursday, 28 March 2013

Guest Expert in Combustion: Professor Ju:

Before getting into our planned question and answer session, Professor Littman gave a brief summary of some of the areas of interest of Professor Ju. He mentioned that Professor Ju was heavily involved in the engineering department at Princeton, especially on projects centered around combustion processes(within jet engines and ground vehicles including plasma ignition, supersonic combustion) the use of nanomaterials. Additionally Professor Ju is heavily involved in developing clean electricity sources and is involved in the sustainable energy program at Princeton.

Before opening to questions, Professor Ju gave a brief summary of the state of energy production in the world today. 85% of the world’s energy demand is met by means of combustion. 20% is met by Nuclear energy and a mere 0.0005% is met by solar energy. Commenting on Wind energy, Professor Ju reasoned that although wind provides a fair amount of energy during peak periods of wind, off-peak periods have to be heavily compensated for. Other technologies such as hydro-electric power were mentioned in passing, but special attention was drawn to the option of natural gas and in particular Fracking technology as a sustainable energy source to be developed.

After this introduction, the discussion was opened to some of the questions we had prepared before in class.

  • Please explain the advantages and disadvantages of different gasoline additives and impurities (in particular: leaded and unleaded gasoline/petrol, ethanol, nitro-methane).
    Please explain the significance of high octane rating and a high compression ratio with regard to engine performance.

Lead increases the octane rating of a fuel which is a measure of the pressure and temperature which a fuel may be brought to before it spontaneously combusts (homogenous ignition) causing knocking. The higher the octane rating of a fuel the more the higher the temperature and pressure the fuel may be brought to without spontaneously igniting. Higher performance engines require higher octane rating fuels in order to be able to put more pressure down on each power stroke of the engine.

Lead performs a similar function to other additives, such as alcohols, and aromatics like toluene and methyl benzene. Alcohol is more effective at increasing the compression ratio than lead, however lead is less expensive. Lead also produces toxic emissions, which is why most countries have banned the use of lead in petrol. Professor Littman also noted that people used to know not to grow plants near to roads as the lead oxides would be absorbed by the plants and inhibit growth.

When asked about octane ratings and what would happen if a high performance engine were to be fed with low octane fuel, Professor Lu explained that there would almost certainly be knocking. However he noted that high tech cars such as Mercedes currently have sensors which detect the octane rating of a fuel sample and automatically retard  or advance the engine accordingly.

When asked what the substantial difference between diesel and gas is, Professor Lu explained that both are hydrocarbons(molecules composed of carbon and hydrogen) but diesel and gas have different chain lengths. Diesel is slightly longer than gasoline, meaning it combusts less readily than gasoline.

Nitromethane (or Nitro, CH3NO2), Professor Lu explained burns far more readily than most hydrocarbons because of the presence of oxygen in the compound. It therefore requires less atmospheric oxygen in order to fully combust. It is in a sense pre-oxygenated fuel.

  • How does a turbo/super charger work?

A turbo charger increases the internal pressure of the reaction chamber and fuel, meaning that more fuel may be injected, and may combust per power stroke; the more fuel which combusts during each stroke the greater the power per stroke and the more powerful the engine.) Pressurized chambers are generally at pressures at  or around 2 atmospheres.

  • Please explain the recent developments in gasoline diesel mixtures resulting in an increase in efficiency.

Professor Ju gave a thermodynamic formula for calculating a measure of fuel efficiency

n = 1- (1/gamma^phi)

Where gamma is the compression ratio and phi is an experimentally determined value in the range of 1.2 -1.4 (meaning not specified.)

He explained that gasoline has a cylinder to wheel efficiency of approximately 30%, diesel 38% and new fuel mixtures containing alcohol have roughly 40% efficiency.

  • What are the alternatives of gasoline combustion powered vehicles (gasoline/electricity hybrids, hydrogen, bio-fuels.)

Professor Ju was adamant that Hydrogen vehicles were not an alternative to gasoline vehicles. Although H2 combusts efficiently, it requires a pressure of 3000psi in order to cram enough fuel into an engine to yeild the same power as gasoline. Producing H2 from CH4 is extremely expensive and has a yeild of only 38%. H2 is also so reactive that it knocks very easily, meaning that H2 engines would have to be tuned incredibly carefully.

Professor Lu was a large proponent of Hybrid engines and praised the Prius for its efficiency and original approach to electrical engine power. He explained that the engine and electrical power systems run simultaneously in a Prius, complementing each other .

  • Professor Littman inquired about the HCCI and RCCI projects which Professor Lu is working on.

HCCI technology combines gasoline and diesel engines in order to create an engine which is capable of plasma ignition/homogenous ignition.As mentioned above; Gasoline has a lower compression ratio than diesel and so is more prone to ignite at high temperatures and pressures. This fact is exploited in an HCCI engine where no spark is used to ignite the fuel, rather the fuel is brought to such high temperatures and pressures that the mixture reaches the activation energy for combustion without a spark.

RCCI – Reactivity Controlled Compression Ignition uses more gasoline than diesel.

One final note was that what determines how much an engine’s timing needs to be retarded or advanced is the flame propagation of the type and amount of fuel being used (namely how long it takes for the fuel to sufficiently combust.)

Discussion of Readings:

Some general bits of information were highlighted in the discussion of the first text, namely that the power of an engine is determined by the volumes of the cylinders and that the size of the throat on a carburetor is important as the breathing ability of an engine is proportional to the power yielded by the engine.

Summary of Tuesday’s Lab period:

Frame: The frame group did inventory, filed the welding around where the crack had been filled in and sent parts for powder coating.

Bottom end: The bottom end did inventory, cleaned and made a list of parts to buy.

Electrical: The electrical group continued to work on the peculiar wiring of the battery and alternator.

Top End: The top end measured the spring constant of the old and new springs and took pictures of the progress being made in lab.

Clutch: The clutch group were praised for their good work on the 58’s clutch, which is in good working condition now.

Reading assignment:

Zen and the Art of Motorcycle Maintenance – Chapters 12-14

In-Class Presentations:

Professor Littman specified that presentations ought to be 15-20 minutes long.

The schedule is as follows:

4/11     Bottom End

4/16     Top End

4/18     Electrical

4/23     Clutch

4/25     Frames, Forks and Wheels


Tuesday, March 26 2013

Assigned Reading for Thursday:

  • Detonation-energy-updated
  • Combustion-chemistry
  • My-little-deuce-coupe-new

(Articles can be found in 64 Tiger Cub -> 64 Data)

Began a new section of the website: “Problems”

First major problem to be listed: Crack in the frame
A major crack was discovered after sand-blasting the frame.
The first general solution to this problem is to cut out a section of the frame and weld a new section in, in it’s place (however it can be difficult to align the insert correctly)
Instead Glen opted for the second general solution: Pilot holes were drilled at either end of the crack, a V-groove was drilled along the crack and steel was welded into the groove.
Learned about Magna-flux testing, a method used to find concealed cracks in frames.

Highlights of what was done in lab(March 14th):

General cleaning of screw threading and components.
Valve seats cut and spring constant of old springs measured.
Gasket CAD design was completed and new gasket was cut.
A few washers, screws and the Rotor key were discovered to be missing, but other components were found still screwed into the bottom end of the engine.

Professor Littman reminded us to ensure all galleries are clear.

Discussion on Graded Presentations:
They should:
– be ~15 minutes long
– be Power Point Presentations
– include explanations of the section’s parts and their workings
– include computations relating to power, gear ratios etc (where applicable)
– be completed in class in the weeks before reading period (2 presentations per class)

Prepared for next visiting expert in Combustion: Professor Ju

Wrote a list of questions:

  • Please explain the advantages and disadvantages of different gasoline additives and impurities (in particular: leaded and unleaded gasoline/petrol, ethanol, nitro-methane).
  • Please explain the significance of high octane rating and high compression rating with regard to engine performance.
  • How does a turbo/super charger work?
  • What are the major factors affecting fuel efficiency which are taken into consideration when designing motorcycles and other vehicles such as SUVs?
  • What is the relationship between the cc’s of an engine cylinder and the possible horsepower of the vehicle? How can one increase the horse power of an engine? How can one decrease the loss in power in transmission?
  • Please explain the recent developments in gasoline diesel mixtures resulting in an increase in efficiency.
  • What are the alternatives of gasoline combustion powered vehicles (gasoline/electricity hybrids, hydrogen, bio-fuels.)
  • What are some of the issues which affect the design of exhaust pipes (why do some cars have two exhausts)?

Prof. Littman gave a demonstration of a two gear transmission system constructed from Meccano.

Lastly we did a calculation of the minimum thrust-stroke power required to accelerate a motorcycle and rider of total mass 400lbs (given specific gear ratios and given a static friction coefficient of 1.)