Structures and Mechanics with fischertechnik Super Crane Challenge – Level 3

1. Structures and Mechanics with fischertechnik Super Crane Challenge – Level 3

2. What You’ll Learn… • The history of cranes • The mechanical principles of pulleys • How compound pulleys can be used to gain mechanical advantage • How cranes are designed to lift heavy loads • How cranes are engineered for structural strength • How principles of statics and mechanics are combined to maximize performance of a complex machine Stuff You’ll Need… • Fischertechnik Profi Mechanic + Static Set • Mechanic + Static Activity Booklet • Mechanic + Static Assembly Instruction • Digital camera

3. ePortfolio Suggestions… • Before you begin the activities in this Learning Launcher, write down anything you may already know about cranes and how they work. • List three interesting things you learned from the What You Should Know… section. • Keep a glossary of new words you learn. Pay particular attention to the bold, italicized words you find. • Describe how you modified your crane design. What modification ideas worked best? Which ideas did not work as you expected? Explain which modifications were mechanical and which were structural. • Take pictures of your fischertechnik models and label each of the parts. • Take pictures of a real cranes or pulley systems, or find them on the internet, and show how they are similar to, or different from, your models. • Answer each of the questions in the Activity Booklet. Record your observations in your Project Planner. • Create a narrated video demonstrating how you modified your crane and how it works.

4. What You Should Know… Before beginning the activities in this Learning Launcher • You should already be very familiar with the fischertechnik construction system. • You should understand how machines create mechanical advantage. • You should understand the different types of simple machines, especially pulleys. • You should understand the basic principles of statics. • You should be familiar with engineering structures using truss systems. If you are not familiar with any of these concepts, you should review Level 1 and Level 2 Learning Launchers including Machines and Gears, The World of Statics and Building Bridges.

5. What You Should Know… The Crane… We’ve all seen cranes at work. You’ve probably seen them used in building and bridge construction. You may have seen them loading large containers on ships or trains. You’ve probably seen stationary cranes and cranes mounted on mobile platforms like trucks. Cranes are machines designed for lifting. There are many types of cranes and each is engineered to perform a different type of lifting job. Some cranes look so delicate, it’s hard to imagine that they can safely lift heavy weights. Have you ever thought about how cranes are designed and how they work?

6. What You Should Know… Cranes throughout the ages… Cranes have been used to help lift heavy loads for a long time. Cranes were invented by the Ancient Greeks in the 6th century B.C. Up until that time, ramps were required to lift heavy loads. Cranes were further improved and used extensively during the Roman Empire. Early cranes relied on men or animals to provide the lifting force. Later, windmills and watermills were also used for this purpose. Steam engines provided the power for the first modern machine-powered cranes in the 18th and 19th centuries. Simple Roman Crane called a Trispastos Today’s cranes rely on internal combustion engines, electric motors or hydraulic systems for power.

7. What You Should Know… Crane engineering… Cranes are sophisticated compound machines that demonstrate several principles of mechanics and statics. The mechanical aspects of cranes rely on pulleys, gears and levers to provide mechanical advantage. Since cranes need to lift heavy weights, they must be structurally stable as well. Size and weight is an important design specification for many cranes that must be moved from one job location to another. These cranes are carefully engineered with complex truss systems to provide structural strength. Modern Crane Design

8. What You Should Know… Pulleys… Pulleys perform an important function in all types of cranes. From your earlier work, you may recall that the pulley is one of the six types of simple machines. A simple pulley system consists of a rope or cable channeled over a freely rotating wheel. A simple pulley changes the direction of force but does not provide any mechanical advantage. The force necessary to lift an object is equal to the weight of that object. Simple Pulley System

9. What You Should Know… Pulleys… In order to gain mechanical advantage, a compound pulley system is necessary. By increasing the number of pulleys, we increase the number of loops of rope or cable in our machine. This allows us to trade force for distance (the length of rope) and reduce the force necessary to lift an object. This principle is similar to levers and gearing systems you may have used in other Learning Launcher projects. As you can see from the drawings below, the simple pulley system (diagram 1) does not provide any mechanical advantage. The two-pulley system (diagram 2) reduces the required lifting force by half. The four-pulley system (diagram 3) requires only one-fourth the lifting force of the simple one-pulley system. Force (in Newtons) required to lift an object using different pulley systems

10. What You Should Know… Understanding compound pulley systems… To better understand this principle, let’s build a lifting tackle and experiment with different pulley systems. The lifting tackle activity is found on page 34 of the Activity Booklet. Assembly instructions begin on page 75 of the Assembly Instruction book. Experiment with systems using 2, 3 and 4 pulleys. Activity Booklet Assembly Instruction Lifting Tackle

11. Do It! Super Crane Challenge… To begin this challenge, build the crane found on page 39 of the Activity Booklet. Include the motor unit in your model crane construction. Assembly instructions begin on on page 108 of the Assembly Instruction book. Activity Booklet Assembly Instruction Crane

12. Do It! Super Crane Challenge… The next step in your Super Crane Challenge is to modify your model crane to lift the heaviest weight possible. You can use any parts found in your fischertechnik kit. Be sure to document your engineering process in your ePortfolio. Describe how you decided to modify your crane. Explain both the modifications that worked as you expected and those that didn’t. Describe both the mechanical and structural improvements you made to your crane and how they work together to accomplish your objective.

13. Are there components from other SmartLab kits you can use so your crane can lift even heavier loads? Be sure to ask your Facilitator before you try this one! Can you calculate the total mechanical advantage of your crane? Go online to learn more about different types of cranes and how they are designed. What are the largest cranes ever constructed? Go online and find out. Try building some of the other projects in the Mechanic + Static Assembly Instruction book. Or design one of your own. Go online and search for “fischertechnik projects”. Check out some of the amazing things people have built using this sophisticated modeling system. Extend Yourself…