Final Structure design
     Base Plate (x2)

     Arm (x4)

     Assembled Structure

Solution Preliminary Model

     Exoskeleton Model

          Propellor in Multiple positions to illustrate a full rotation

     Internal Skeleton Model

Solution Development

Alternate Solutions Rationale

I.                   Struts: Quad Branch and Tri Branch

The structural layout of the multicopter is very important. There are many options for the general layout of a multicopter: quad, tri, single axis, octo, and hexa-copters. However, an analysis of the resource and monetary specifications of each of these options reveals that hexa, octo, and single axis-copters are much more expensive and require higher-grade materials due to the complexity of each design. Therefore, I further researched quad and tri-copters. In addition, the structure will be constructed as an internal skeleton of aluminum or steel punched half channel struts anchored to a custom 3D printed plastic base plate and the corners of an aluminum strut square or triangle, supported by a sub-structure and landing gear; or an exoskeleton of heat formed plastics.

Quad-copters are the more common of the two layouts. A quad-copter generally involves four branches with one motor on each branch. A traditional quad-copter provides great stability and maneuverability at any size. However, quad-copters are more prone to turbulence than its octo and hexa-copter relatives, and cannot operate with one nonfunctional motor, but are capable of surviving a fall with three of its motors operating.

Tri-copters are effective options at smaller sizes. However, it is very difficult to cancel out the torques of the rotors on a tri-copter, which leads to lower stability and requires vibration resistant materials or buffers. Furthermore, the loss of a single motor often results in complete structural failure.

Solutions
Specifications ranked 1-5	Tri-Branch	Quad-Branch
Maneuverable	3-equally maneuverable, however sacrifices in stability make control more difficult.	4-Very maneuverable when piloted correctly.
Stable	2-Torques unbalanced, results in low stability on larger frames and unwanted vibrations.	3-Torques are cancelled by adjacent motors, however moderately low motor count requires larger rotors and lower motor speed, prone to adverse vibrations.
Lightweight	4-Lesser number of branches and motors significantly reduces the weight of the structure	2-More branches and motors, and usually larger size results in much more weight.
Easily Constructed	2-Triangular layout requires specialized parts to construct.	3-Rectangular layout utilizes simple angles and
Adaptable	3-Triangular layout makes modifications or additions difficult.	5-Rectangular layout offers many opportunities for modifications.
Net Score out of 25	14	17

As evidenced by the specification analysis of the tri and quad-copter layouts, the quad-copter design is superior. Overall, the quad-copter provides good maneuverability, better stability, easier construction, and better adaptability. The sacrifices in weight can be overcome using a coaxial motor layout if necessary.

II.                Landing Gear: Individual Pontoons and Ring Pontoon

The landing gear of the multicopter will support the entire structure upon landing. In addition, the landing apparatus must include pontoons that keep the structure above water when landing on a body of water. There for, the landing gear must include some sort of suspension and a means of flotation.

One option for this design problem is to include individual pontoons on each of the legs of the multicopter. This allows for free movement of each suspension system, and thus increases the stability of each landing and takeoff.

Another viable solution is a complete ring pontoon that attaches to each leg of the landing gear. This design restricts the suspension system to a single plain; however, a complete ring makes better use of the available flotation space beneath the multicopter.

Solutions
Specifications Ranked +,-	Individual Pontoons	Ring Pontoon
Flotation Ability	-	+
Stability	+	-
Net Score	S	S

Both designs offer very important features. Thus, I will combine the two designs. A complete ring of flotation material will be suspended below a suspension system and branch off into individual landing pegs covered in the same flotation material.

III.             Prop Layout: Coaxial Motors and Single Motor

In order to achieve flight, the multicopter must have propellers and motors. Depending on the needed lift capacity of the multicopter, each branch can support either one or two motors and propellers.

One motor on each branch achieves a simpler, more reliable system, at the cost of more turbulent flight and less lift capacity. This option also adds much less weight to the frame

Coaxial Motors on each branch increases the risk of system failure due to the deeper complexity of the circuits. However, the doubled amount of propellers provides a smoother flight and the maximum flight capacity in the smallest area. In addition, a quad-copter with 8 rotors is capable of operating with one failed motor.

Solutions
Specifications ranked 1-5	Single motor	Coaxial motors
Reliable	4	3
Stable	3	5
Lightweight	4	2
Effective lift capacity	2	4
Net Score	13	14

Coaxial motors provide great lift capacity and stability, but sacrifice reliability and weight. Single motors offer reliability and low weight, but lose stability and lift capacity with the less motors. Thus, I cannot confidently decide between the two options without further developing the other aspects of the project. Depending on how much weight the quad-copter needs to lift, either coaxial or single motors can be utilized.

IV.             Steering Method: Electrically Controlled and Mechanically Controlled

In order to direct the multicopter to a sampling location and back there must be a mechanism or electrical component capable of steering the vehicle.

Mechanically, the vehicle could be steered with a horizontally oriented propeller that rotates on a vertical axis. The multicopter would move in the direction the propeller faces. This option provides more stability and control over the alternative, but greatly increases the weight of the multicopter.

Electronically, the vehicle could be steered by adjusting the speed of each motor in order to lean the multicopter in the desired direction of travel. This method is by far the most common in multicopter technology. The largest benefit of the electrically controlled option is the lack of any additional weight and the inherent reliability of simplicity.

Solutions
Specifications ranked 1-5	Mechanically Controlled	Electronically Controlled
Lightweight	1	5
Reliable	3	4
Stable	4	2
Net Score	8	11

The electronically controlled solution is desirable because of its simplicity. Also, this method adds no additional weight to the vehicle and offers a faster, more efficient means of transportation that utilizes less battery power.

Alternate Solutions

Executive Summary of Research

Executive Summary of Research

            My task for the WaterCopter project is to design and craft a multicopter frame and lift system to be used in the transportation and collection of water samples. In order to create a successful product I must consider the materials used in the structure, the layout of the structure, the arrangement of the motors and propellers, and the effect the materials used in the structure will have on the samples the final product will be taking.

            Many materials are useful in constructing a multicopter (see table 1). The overall goal of the materials is to be light, durable, and strong. Cost is also a factor that must be taken into consideration.

Material	Pros	Cons
Carbon Fiber	Lightweight, strong	Brittle, expensive, hard to machine, hard to glue
Fiber Glass	Easier to machine and glue, less expensive, less brittle	Slightly heavier, slightly less strong
Aluminum	Easy to machine and construct, cheap, readily available	Less strong, heavier, easily warped, carries vibrations, blocks radio frequencies
Injection Molded Plastic	Zytel is very strong and light	Most other forms are cheap and easily broken, less available, requires special machinery
Vacuum formed kydex	Very durable, great for water resistant or water proof products	Requires special machinery

There are also many options for the layout of the multicopter. Common types are the tri-branched, quad-branched, and the single-copter (Advanced Multicopter Design). 

One can attach one rotor to each branch, or attach two adjacent rotors, stacked in a coaxial arrangement. A single rotor arrangement is more efficient, however a coaxial arrangement is more stable with smoother control and provides the most lift in the smallest area, and less weight than an hexacopter or octocopter (Advanced Multicopter Design). Coaxial layouts permit one motor loss, however they are more complex and thus less reliable, heavier, and more costly.

Rotor size is dependent on the intended lift capacity and clearance limit of the structure. Larger rotors are more efficient but more prone to vibration and provide less stable flight than smaller, faster rotors (Advanced Multicopter Design). Another very important consideration for the materials used to construct the frame is the effect it will have on the samples we take.

             Different materials will release trace amounts of chemicals into the water that may skew the analysis results. For example, most plastics are usable in the analysis of inorganic compounds. However, most plastics skew the results of organic compound testing if they come in contact with the water being collected. Materials that are generally approved in use for the sampling of organic and inorganic compounds are fluorocarbon polymers, stainless steel, glass, and ceramics (Wilde, Table 2-1, pg. 6). Softer and more flexible plastics are more prone to contaminating samples (Wilde, pg. 7).

            In summary, the materials must be strong, light, and not release any harmful compounds into the water. The layout must be capable of lifting the structure and the water sample. In order for the WaterCopter to be successful, the materials, layout, and environmental impact of the structure and lift system must be optimized.

Testing Procedures

Test Type: Assessment

Test Stage: Preliminary

State of Solution: On, stationary on floor adjacent to table

Condition of Testing Stage: Controlled environment, open area

Tools and Equipment Required: Table

Testing Procedures:

1.      Activate the rotors to ensure functionality

2.      Activate the rotors and maintain hover approximately

one foot off the ground for at least ten seconds

3.      Raise altitude to five feet off the ground

4.      Steer the vehicle to directly above the table

5.      Slowly lower the vehicle to approximately four inches off the table

6.      Cut power to the rotors

7.      Inspect landing gear and suspension to ensure proper functionality

Test Type: Validation

Test Stage: Secondary

State of Solution: On, stationary on floor outside of testing stage

Condition of Testing Stage: obstacle course set around a small pool atleast three feet deep filled with water, controlled environment

Tools and Equipment required: obstacles for vehicle to maneuver, small pool, and large fan

Testing Procedures:

1.      Pilot vehicle through obstacle course

2.      Return vehicle to starting point and land

3.      Repeat step one with the large fan on and aimed at the course

4.      Once through the course, land the vehicle on the water

5.      Complete testing to analyze the water sampling mechanism

6.      Repeat step three in reverse

7.      Land the vehicle at the starting point

Specifications and Limitations

1. Final Product must operate in varying weather conditions
• -          Capabilities of electrical components
• -          Power of motors
• -          Stability of vehicle
2. Control System must be remotely operated and have a large range and endurance
• -          Battery life
• -          Size and weight of product
3. Structure and flight system must be small enough to maneuver dense environments
• -          Amount of water needed for research
• -          Lift capacity to size ratio
4. Mechanisms must operate on battery power
• -          Power required by mechanisms
• -          Endurance of battery
5. Structure and mechanisms must have easily replaceable or reparable parts
• -          Complexity of structure and mechanisms
6. Structure must be durable
• -          Strength to weight ratio of materials
• -          Simplicity of mechanisms
7. Final product must leave minimal environmental impact
• -          Sound pollution of motors
8. Final Product must be able to land on water
• -          Water resistance
• -          Flotation

Design Brief

Team Design Brief

Develop and manufacture a remotely operated vehicle to survey and take samples, causing minimal negative impact on marine environments inaccessible or dangerous to the researchers and scientists that control and utilize this vehicle periodically in locations of interest, in order to research water quality.

Flight System

Develop and manufacture a structure and aerial lift system, used periodically throughout the year to maneuver through dense environments and carry water samples from bodies of water for scientists to analyze and record, to allow for less obtrusive research in locations less accessible to humans.

Background Information

The Problem

Many marine biologists and chemists require the collection of water samples to conduct research on the conditions of various bodies of water. The primary method of sample collection is by hand from a boat or shore. Samples are also taken using tools such as Kemmerer bottles or underwater drones, but must be deployed manually and utilize a tether. Although these methods have been the norm in the past, there is now concern that the vehicles used to take these samples disrupt the environment unnecessarily, and may even contaminate the samples taken. In addition, areas that should be tested for water quality are left untouched because they are inaccessible by boat or dangerous to access from land. Therefore, we must create a vehicle able to access bodies of water remotely, take a pure water sample with negligible environmental impact, and return the sample to the user for testing.

The Customers

The projected costumers of the product are research scientists, marine biologists or chemists, ecologists, park employees, or any person interested in marine research. These customers need samples to analyze in order to determine the healthiness of an ecosystem. Our product will be capable of sampling water remotely. These samples must be brought to a laboratory to be tested.

The Case

This case must be addressed because contaminated data is a big problem in the scientific world. Scientists want the purest data for accurate testing. Improper data can cause fluctuations in results that require retesting and waste money. These fluctuations in results can lead to larger errors later on that build on the problem. In addition, most scientists have the best interests of nature at heart, and providing a cost effective way to take pure samples with minimal environmental impact addresses all of these issues.

 The Stakeholders

The stakeholders of the project are those willing to contribute their time and possibly money to our project in order to receive a completed product that will benefit them in the future. These stakeholders could be those in charge of research facilities, employees of those research facilities, those in scientific disciplines, as well as those invested in our project because of interest in our goal for the project. 

The Mood

The intended moods that we wish to show in our project are efficiency, reliability, and durability. We want our quad-copter to be efficient in all of its methods in order to become a realistic source of water collection. We want the quad-copter to be reliable so that scientists in the field can feel confident in the data they receive. Finally we would like to craft a durable product capable of surviving the difficulties of water collection.