Do-It-Yourself Engineering

Your final DIY project is a tribute to cartoonist Rube Goldberg, famous for sketching machines that perform the simplest tasks by the most complicated means. Accordingly, combine twenty design elements from this course - from airfoil to electric circuit - to create a machine that will click a computer mouse.

Test the limits of small, inexpensive, off-the-shelf hobby motors by building a motor-driven crane capable of lifting 100 pounds - a tall order for a motor that weighs only a few ounces! First, construct the world's simplest electric motor to gain insights about how they work.

The pendulum clock was the standard for precise timekeeping for centuries. Plan and build one using your newly acquired knowledge of gears.

Test your water turbine, comparing its performance to the theoretical ideal. Next, modify it by adding a set of spur gears that will allow the machine to lift a 6-pound weight, which is well beyond its ungeared capacity.

Harness the power of moving water by building an impulse turbine capable of lifting a 2.2-pound weight through a distance of 2 feet.

Plunge into hydraulics, learning how force is transmitted from actuators to hydraulic cylinders through fluid-filled lines. Then use this knowledge to design and build a hydraulically powered mechanical arm that can grasp and manipulate a concrete block - controlled by four hand-operated syringes.

Build your model ballista. Then construct two other types of catapult - the onager and trebuchet - designed such that they store the same amount of energy as your ballista.

Delve into the history of the most potent artillery weapons in the era before gunpowder: catapults. Examine the workings of the ballista, onager, and trebuchet.

Finish your launch preparations by building a theodolite to measure the altitude of the rocket's trajectory, building a launch pad, packing the parachute, choosing a safe launch site, setting up the site, and coordinating the activities of the mission control team. Once all systems are go, conduct the countdown and press the firing button...

Get a taste of electrical engineering by designing and building an electric launch controller that will ignite your rocket engine safely. Design a circuit that meets all code requirements.

Put together your model rocket, paying special attention to the engine mount and fins, then giving the completed vehicle a drag-reducing finish. Apply the science of aerodynamics to calculate the required diameter of the parachute.

Tackle the problem of designing a model rocket that carries a miniature video camera to 500 feet and then returns safely to earth by parachute. In this lesson, focus on selecting an off-the-shelf model rocket engine that can do the job.

Now tinker with helicopter aerodynamics by adapting the classic Penni model helicopter design used by many hobbyists. Discover the importance of countering the main rotor's torque, and investigate the mechanical genius of the rotor hub - fortunately simpler on our model than on full-size aircraft!

Complete your model plane by assembling a rubber motor that will serve as a source of power. Design, carve, and install an efficient propeller.

Dig deeper into aerodynamic science so you can choose an airfoil shape and appropriate wingspan, aspect ratio, fuselage length, and stabilizer dimensions for your model plane. Pay special attention to aerodynamic stability and such factors as the dihedral angle of the wings, noting these features on full-size aircraft.

Start your project on fixed-wing flight the way the Wright brothers did: by building a wind tunnel. Use it to test different wing shapes at varying angles of attack, exploring the phenomena of lift, drag, and stalling.

Who has not tied a paper cup to a helium party balloon to make a primitive airship? In this lesson, design and build a far more advanced version: a radio-controlled blimp that you can remotely pilot around your house.

Build your concrete sailboat. Consider the enhanced strength of a concrete shell that has been formed into a curved shape - a feature exploited in many buildings.

It may sound suspiciously like a lead balloon, but a concrete boat can be made to float. Your engineering challenge is to create a concrete sailboat that can operate safely in 10-mph winds.

Elegant and efficient, the suspension bridge is your next DIY effort. Span the same small stream as in the previous project, but support the deck with suspension cables draped between two 5-foot-tall towers.

Design and build an 8-foot beam bridge capable of carrying a swarm of pedestrians across a small stream. First, consider three alternative concepts, with beams made of identical wood, but of different configurations.

Now that you understand the forces your cardboard tower must withstand, conduct a series of compressive and tensile strength experiments to determine the size and shape of your structure's beams, columns, and braces. After completing your design, build the tower using ordinary wood glue and simple tools.

Get started on DIY project number two: use cardboard to build a tower capable of supporting a 100-pound gravity load and a 10-pound lateral load simultaneously. This exercise closely replicates problems faced by real-world skyscraper designers.

Follow the seven steps in the engineering design process to create a golf ball launcher that can hit a target ten feet away. Apply the principle of conservation of energy to select the right steel spring for the job.