INDUSTRIAL DESIGN

Assignment # 7 - Sears DX high school competition or other ones (Velux or this one House in a Forest)

Task:

You are to research and innovate a re-imagined design challenge choice found in the brief at the DX website (PDF link to the various competition categories). You are to look at all questions normally identified with the research then come up with sketches going from emotional concept, to thumbnail, to detailed sketches with pullouts. Then you are to enter a modeling program of your choice (I would recommend Sketchup as it's free) and make a 3D model, as well as elevations (likely in AutoCAD) including relevant detail, dimensions and pullouts. If you want to make more realistic 3D models, then you may want to sign up for and download AutoDesk Inventor (they make AutoCAD) which is free for 16 months for students. Finally, you are to come up with a scale model of your product. It can be made from clay, wood, styrofoam or whatever you want. The model need not be functional or made from the industrial materials as it would be if it was full-sized. But it should look as close to your imagined finished product as you can make it. The scale depends on your project.

NOTE: While you need not get into excruciating details in your project, it is important to paint your ideas with a relatively detailed brush. For example, while you may not demonstrate how the fasteners are grafted into the bike helmet, but, you should show the general flow of how the fasteners would wrap around the subject's head. That is to say - show how things will work without necessarily knowing how to get the finicky details sorted out about how metal pieces get welded, or electrical connections are made etc... For the purposes of the competition, it is VITALLY IMPORTANT that you ensure you document every step along the way including notes and photos.

Best yet - this assignment pulls double-duty. Not only is it a good project for ID, it is also a national competition. It will get your name out there but also get you some prizes. All entries must be submitted by no later than May 1st in order to be evaluated for the competition.

• Registration form (PDF)
• Design ideas and background information

Evaluation:

• Before construction begins - paper sketches must be assessed by me to ensure the project is doable and you've thought through the details.
• Because so much of this project will be done outside of class hours, ensure you keep up to date on hours and tasks accomplished at home with THIS LOGSHEET
• After completion, sketches, a final elevations (CAD or hand-drafted) a 3D model and a scale model will be submitted with the product design report.
  • in your product design report include all sketches, elevations and 3D models you have created. Think of the product design report as a 1-2 page document like the technical reports you have done in the past for design classes. Make sure you have addressed the ID questions in your research into the product.

Mechanical Engineering

Assignment #7 - Trebulicious & Variation

You are to create, in miniature, a fully functional trebuchet that is capable of launching a 100g weight no less than 1m distance.

The goal is two part:

1. See who can propel the 100g weight the furthest
2. See who can be most accurate in hitting a target

2018 Variation: You are to create, in miniature a fully functional medieval siege engine capable of hitting a static target no more than 3m, but less than 2 m away.

The goal is:

1. The first to score 3 hits against their opponent in a sequentially turned "battle".
2. If the enemy is incapacitated during the course of the combat the competition will end in the favour of the "last one standing"
3. The competition will be "round robin"

Description:

The counterweight trebuchet appeared in both Christian and Muslim lands around the Mediterranean in the twelfth century (though was likely developed some 700 years earlier in China). It could fling projectiles of up to three hundred and fifty pounds (140 kg) at high speeds into enemy fortifications. This created a far more formidable siege engine than the catapult which was limited in both range and durability. (2018 Variation: scorpions are allowed but are limited to the materials listed herein.

General Rules:

The trebuchet can be no taller from ground to the pivot point where the arm passes through of 30 cm. The arm itself can be no longer than 70 cm.The goals are to make both a robust design that is capable of launching a 100g mass as far as possible, but also to be able to be accurate for the second portion of the competition (given a couple of tries). In order to qualify for competition points, the 100g mass must launch no less than 1m from the trebuchet's arm's pivot point.

2018 Variation:

• The war machine must be contained within a 30cm cubed area except for any throwing arm that can pass outside during operation

All contestants are expected to follow the engineering rule of ethics (no cheating). Failure to comply will result in forfeiture of a grade.

Materials:

You are to use scaled 1:6 2"x6" wood for the structure for this competition. Any other pieces must be supplied from home, but be subject beforehand to approval by me (2 wildcard materials). No part of the war machine may be bought from parts especially designed for such activity. Wood glue will be the adhesive used to glue members of wood to each other. Allow a 24h cure time between the last stages of construction and the test date.

Testing:

1) Distance

You will attempt to launch a 100g mass as far as possible using your trebuchet. No interaction may be made with the device after you trigger it to release. The mass will only be able to be launched from the inertia given to it by the falling counterweight.

2) Accuracy

You will attempt to launch a 100g mass exactly 2.5 m away (at the opponent if there is one) from the pivot arm of the trebuchet. You will get 3 attempts to do so (or if there are 2+ competitors you get a random chance to go first). The average of the distance away from the 2.5 m mark will be taken as the competition entry.

2018 Variation:

• You will flip a coin to see who goes first. Competitors will then take turns attempting to score a hit against an enemy machine. A hit is considered a point only if the machine is struck while the projectile is in-flight, not rolling/tumbling.
• Adjustments may be made between individual turns. No major reconstruction/repair may be made after the competition begins.

Helpful Calculations

A very simple model found online just uses the mass of the projectile (m2), the mass of the counter weight (m1), and the height the counter weight falls (h):

Range (max) = 2 * (m1/m2) * h

Now the efficiency of the trebuchet will cause this model to be off by quite a bit. But once you have a working trebuchet, we find this model works well when we vary m1, m2, or h. We assume we have a take off angle of 45 degrees above the horizon. This solution is based on the classic max range ballistics problem - 45 degree take off angle. It also assumes converting all the potential energy of the counter weight to kinetic energy of the projectile. That is why the efficiency issue comes up as a lot of energy is lost due to friction in the moving trebuchet. If the projectile spins a lot then it will travel a shorter distance as the potential energy is split into kinetic and rotational energy. Projectile shape and wind will also vary the results.

Evaluation:

• Before construction begins - paper sketches, and a 3D Sketchup model must be submitted for assessment. After completion, sketches, a final CAD file and a 3D model will be submitted with the design report. The Sketchup model will include all relevant details as pullouts.
• From the isometric sketch, you are to create front and side views as well as top view of your trebuchet in AutoCAD. You will use these in guiding your construction.
• Trebuchet construction - overall design of the finished product will be evaluated including: dimensions, style and adherence to the working drawings.
• Distance results
• Accuracy results
• Self-Evaluation/ write-up. (Not for 2018 competition)

Mechanical Engineering

Assignment #7 - Freebird Plane Challenge

You are to design, build and test a plane that is to be launched, travel a distance of 6m, turn at an angle of 45 degrees, then land 2m later in a "landing strip" (bull's eye).

Description:

Students are to design a plane made of materials of their choice. This plane is to travel a distance of 6m forward THEN turn 45 degrees and land 2 m further on in a 1m diameter bull's-eye on the ground whose center is at the 2m mark.

General Rules:

• No plane-specific items may be used in the construction of the plane
• Any and all adhesives are permitted
• The only method of propulsion is the elastic launching the device off of the launcher.
• The angle of launch is up to person/group.
• No interaction may be made with the plane once it is launched

All contestants are expected to follow the engineering rule of ethics (no cheating). Failure to comply will result in forfeiture of a grade.

Materials:

• Individuals/teams will be supplied 2 pieces of balsa wood.

Testing:

Evaluation:

• Before construction begins - paper sketches, and a 3D Sketchup model must be submitted for assessment. After completion, sketches, a final CAD file and a 3D model will be submitted with the design report. The Sketchup model will include all relevant details as pullouts.
• From the isometric sketch, you are to create front and side views as well as top view of your plane in AutoCAD. You will use these in guiding your construction.
• Plane construction - overall design of the finished product will be evaluated including: dimensions, style and adherence to the working drawings.
• "Raceway" results
• Self-Evaluation/ write-up.