File 4: Engineering Solutions

Question 1

3 examples of engineering solutions are?

Answer 1

the beverage can, the paper clip, the passenger jet (Boeing 777)

Question 2

(beverage) What were the material options of the beverage can?

Answer 2

1. iron: heavy and hard to open
2. steel: lighter but still heavy, require special opening device
3. aluminium: light weight, easy to manufacture due to softness and can be made from one single sheat of metal.

Question 3

What are the characteristics of the aluminium can? What are the problems of the aluminium can?

Answer 3

The strenght of the can came from the pressurization of the can and allowed it to be stacked. But pressurization risked the bottom of the can to balloon out (thus not being able to stand). The solution was the inwardly dished bottom (that required thicker metal thus increasing the price of production => made thicker part narrower)

Question 4

Explain the process of manufacturing idea for the opening of the can.

Answer 4

1. required church key opener but not everyone has church key
2. creation of pop tops (detachable): (if too weak. shallow, too deep: too hard to open can) source of environmental failure => potential of pop tops being banned in some states
3. Reynolds Aluminium creates the attachable pop tops

Question 5

Explain how the can manufacturing achieved to minimize manufacturing cost .

Answer 5

by minimizing the material used: from 1970s-1980s the amount of aluminium used per can dropped by 50% by using a tapered top: the top had to be stronger than the can but by reducing the circumference of the top, you minimize the amount of aluminium used

Question 6

What is the key concept of the paperclip?

Answer 6

the springiness of the metal of the paper clip thus creating a range in which the paperclip can be bent and remain springy. beyond this elastic limit, the paperclip would break

Question 7

Before the invention of paperclips, how were papers held together? What were the disavantages? (4)

Answer 7

Pins:

1. hard to put through a stack of papers
2. Pin leaves a hole in the paper
3. you can prick your finger
4. thickening of paper at the corner made it hard to stack

Question 8

What did moving from pins to paperclips require from manufacturers?

Answer 8

required developping a way to bend metal that reduced time of manufacture. the pin was already mechanized (springiness) so paper clips were not a cost substitute of pins.

Question 9

Why were not all of designs for paperclips not patented? give an example.

Answer 9

due to cost and secrecy:

example is the gem paperclip (most commonly used)

Question 10

How did the paperclip out compete pins?

Answer 10

due to the machine that reduce manufacturing cost of the paper clip.

Question 11

Improvements to the Gem paperclip include: (2)

Answer 11

1. plastic coating

2. turned up lip at interior end to make it easier to slide papers (but it increases corner stack bulk)

Question 12

What is the Michelson paperclip>

Answer 12

patented in 1990: paper clip to deal with thicker stacks of paper

Question 13

When did the interest in developping a jet for civilian use commence? Who took the lead of developping it?

Answer 13

at the end of WWII, military jets appeared which sparked the interest for civilian use. Due to postwar state of Germany, USA and British took the lead

Question 14

What was the first commercial jet created?

Answer 14

the Havilland Comet: first in service giving it the first mover advantage

Question 15

What were the design problems of the Havilland Jet? (3)

Answer 15

1. metal fatigue led to explosion of Havilland Comet: small cracks formed around fuselage openings (windows) which got bigger with take offs and landings -> internal pressure increased causing them to explode
2. Comet engineerings based knowledge of metal fatigue on machinery metal fatigue which only showed up after 100000 uses and assumed that the number of landings and take offs is nothing comparable. Thus to minimize the aircrafts weight, they opted to to use less material around fuselage openings rather than more
3. Jet craft fuel is expensive thus want to minimize cost of jet fuel by minimizing weight and flying at higher altitudes where there is less resistance: but flying high requires cabin pressurization and variability in external pressure of fuselage openings thus shifts in internal/external pressure of cabin led to metal fatigue.

Question 16

What was the consequence of all the design problems of Havilland Comet?

Answer 16

airlines and public lost trust in Havilland Comet: allowed Boeing, Douglas, McDonnell to replace it in the commercial passenger market.

Question 17

Why was Boeing 777 created?

Answer 17

at the end of the 20th century: interest in pacific rim markets thus need aircrafts that can travel more than 9000 kn

Question 18

Who carried out the development of the Boeing 777?

Answer 18

United, british, american, cathay pacific, all nippon, japan, delta, qantas (all airlines that had pacific routes)

Question 19

What design features did potential customers of the Boeing 777 desire? (2)

Answer 19

1. wider body (larger armrest) to allow more flexibility in seats
2. large overhead bins

Question 20

What was the design process for older aircrafts previous to Boeing 777?

Answer 20

1. group of engineers worked individually or in teams to design subsystems and parts
2. lots effort to reconcile differences in subsystems (sometime requiring mockups which are really expensive)
3. point assembly: lots of parts did not fit together requiring shims (expensive)

Question 21

Explain the design process of the Boeing 777.

Answer 21

1. use of CATIA (computer aided three dimensional interactive application)
2. design took place in many countries: dedicated communications cables
3. Clash programs: red flashing light when separate design produced interfered with one another
4. CATIA-man: detect manufacturing problems caused by design

Question 22

What were the benefits of the design process adopted for Boeing 777?

Answer 22

reduction in shims used, problems reduced

Question 23

What lessons can be taken from the can, paper clip and boeing 777? (6)

Answer 23

1. improving productivity requires addressing failure and trying to deal with problem as early on as possible to minimize them (from comet and detachable pop tops to CATIA)
2. development cost can be high thus incentive to find economies in design process (computer helps)
3. IP such as patents are important but what is patented is commercial strategy: gem paperclip was not patented but the machine was
4. inventors decide not to patent for secrecy as it secures first mover advantage
5. regulatory threat creates incentive to innovate (poptops)
6. large savings in cost manufacturing (thus increasing productivity) linked to small reductions in material used (paperclip and cans)