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Propulsion

Team 4: Alex Gubler, Audrey Ferraro, Davin Axelsson, Brendan Ekstrom

EDSGN 100

Section 012

10/17/14

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Table of Contents

  1. A Description of the Design Task
  2. Design process/Approach
    1. Concept generation
  3. Prototype/Model
    • Design drawings
  4. Engineering Analysis
    • Calculations
  5. Evaluation
    • Design idea/Concept selection
  6. Summary/Conclusion

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Problem

  • How can we create a cost efficient product that will satisfy our customers needs, yet still be highly effective in achieving our goal of walking on water?

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Survey Says….

  • Target Age: 18-23
  • Target Weight Range: 110 lbs - 200 lbs
  • Desire To Walk On Water: Moderate
  • Willing To Pay: $50-$75
  • Life Expectancy: 2-5 years
  • Preferred Material Composition: Fiberglass
  • Climate Usage: Any Climate
  • Portability (1-5 Scale): 4
  • How Often Used In A Week: Once or Twice
  • Distance Capable of Traveling On Water: 2-5 miles

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What We Deemed Important

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Ease of Use

Portability

Durability

Cost

Safety

Row Totals

Row Total/Total

Ease of Use

1

5

3

2

1/4

11.25

.27

Portability

1/5

1

1/3

1/3

1/5

2.07

.05

Durability

1/3

3

1

2

1/3

6.67

.16

Cost

1/2

3

1/2

1

1/4

5.25

.12

Safety

4

5

3

4

1

17

.40

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​

​

​

​

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42.23

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Design A

  • wooden or plastic “flaps” secured at the bottom of the flotation device
  • supply resistance against the water to help the user move forward
  • 2 on each side

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Design B

  • no propulsion element that touches the water
    • sturdy
  • handles on either side to help lift up each flotation shoe and the user physically moves their hand and foot forward

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Design C

  • 2 funnel-like systems on the bottom of each flotation device
    • water flows easily past the system in the forward direction
    • water pressure due to water captured in funnel adds resistance to backward movement

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Design D

  • paddles loosely connected to side to help move forward
  • funnel-like propulsion system connected to the bottom of the flotation device
    • water flows easily past the system in the forward direction
    • water pressure due to water captured in funnel adds resistance to backward movement

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Selection

Criteria

​

A

B

C

D

Ease of Use

+

0

+

0

Portable

0

+

0

0

Durable

0

0

0

0

Cost

+

+

0

-

Safety

+

-

+

0

Manufacturing Ease

0

+

-

-

Lightweight

0

0

0

0

Pluses

3

3

2

0

Sames

4

3

4

5

Minuses

0

1

1

2

Net

3

2

1

-2

Rank

1 (YES)

2 (YES)

3 (YES)

4 (NO)

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Several Improvements Made

Test 1 Included:

  • Handlebars (deemed unsafe)
  • Sneaker-like shoes attached by gorilla glue (not sturdy and unsafe)

Test 2 Included:

  • Plastic bottles that supplied extra stability and flotation
  • the use of halved plastic bottles for propulsion
  • duct tape, slip on shoes- easy to slip on and off

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Final Product: A Success!

Materials Used:

  • Duct Tape
  • 2-Liter Soda and Milk Containers (recycled)
  • shoe soles
  • twine
  • plastic storage containers

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Creative Element of Propulsion

Uncapped, 2-liter Soda containers to allow device to glide forward in water smoothly and prevent backward movement by the use of water pressure

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SolidWorks Brought Our Propulsion to Life

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Solidworks Helped us to Demonstrate Our Propulsion System

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Simple, Yet Effective, Shoe Design

  • Rubber Shoe Sole super glued to plastic to add comfort and traction
  • Duct tape strap that feet can easily slide in and out of
    • safely able to remove foot when necessary
  • sturdy

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​

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Propulsion Made Us Move (Kind Of)

  • Cut bottles meant to act as propulsion system
  • Design resembled that strongly of jets attached to bottom of ships (aerodynamics), except ours had no exterior energy added
  • Area going into bottle was greater than area exiting, so velocity exiting would be greater than velocity entering
  • Ended up working to an extent (we moved sideways)

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How did we figure this out?

  • A(1)V(1) = A(2)V(2)
  • A(1) = Area Larger Hole = 71.63 square cm
  • A(2) = Area Smaller Hole = 1.651 square cm
  • V(2) = ((A(1)V(1))/(A(2)))
  • Based on design, A(1) > A(2)
  • From formula, V(2) > V(1)
  • Velocity exiting out back of propulsion device allowed our motion

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Show Them The Money

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​

​

​

​

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Total Price: $42.00

Item

Price (dollars)

Plastic Bins (Main Device)

$16.00

Bottles (Flotation Assistance)

$12.00

Shoes (Foot Attachment)

$4.50 (each)

Total Tape and Twine Used

$5.00

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The Pros Outweigh the Cons

Pros:

  • the tester was able to move a distance of 15 meters
    • propulsion was effective
  • feet could be easily removed when the tester fell in the water
    • safety
  • the system supported a wide range of weight and was effective
    • 140lbs to 185lbs was tested
    • cheap- $32.00

Cons:

  • several bottles fell off in the water
    • can easily be fixed by reinforcement
  • slow movement forward
    • propulsion system can be improved upon
  • one shoe strap came undone
    • can easily be fixed by reinforcement

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A Win in Our Eyes

Although our design needs to be more aesthetically pleasing and sturdy before hitting the real market, we believe our design was fairly successful. It was relatively cheaper than most other designs, it was very safe, and it moved forward without sinking. The propulsion needs to be greater before the design is finalized, and this can be done by adding more halved soda bottles on the bottom of the prototype and ensuring that they are secure. The complete product is light enough to be easily carried by our target audience (teenagers and young adults), even though it is large. Overall, our product can be market ready after a few adjustments and details. Safety, the most important feature in our eyes, was not an issue.

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Questions or Comments?