EPISODE 7: Airborne Box

Lesson Plan

Design and Technologies Years 9–10

TOPICS • The development of powered flight • The discovery of specific requirements for heavier-than-air flight • The invention that achieved the first steady flight of a human • The impact of powered flight on society

BACKGROUND Historically, the dream of human flight was one of pure fantasy. Powered human flight had captured great minds as far back as the early 16th century, when Leonardo da Vinci designed his ornithopter. By the late 19th century though, it was still just a fantasy. To make flight possible, we had to invent stable, controllable flying machines that could stay airborne under their own power. By inventing the box kite and successfully flying it in 1894 Lawrence Hargrave paved the way for all modern aviation a decade before the successfully piloted the first powered plane in North Carolina.

Hargrave migrated to Sydney from England in 1865 at the age of fifteen. He was apprenticed in the engineering workshops of a shipping company where he learned his mechanical, design and drawing skills. He also enjoyed adventures while serving as a ship’s engineer on multiple voyages. After he married, Hargrave’s interests turned to science so he became a member of the Royal Society.

By the balloons had soared for over a century, but the skies still lacked any device that could fly under its own power with a degree of control. Heavier-than-air flight requires a careful balance of lift, thrust, weight and drag. To fly, lift must balance weight and thrust must exceed drag. Hargrave was one of a small group who knew that controllable manned flight was the future, but also that achieving it would require mastering the forces of lift, thrust, weight and drag. Hargrave believed the answer to safe stable lift lay in three dimensions. After experimenting with different shapes and formations, he discovered that a kite with two separate cells had the greatest stability and soaring power. 2

He began conducting meticulous scientific trials, but his work failed to interest the public or even his peers. People in the Royal Society often didn’t listen to his lectures because they literally thought he was mad. To rectify his reputation and prove his sanity, Hargrave had no choice but to show that heavier-than-air flight was possible.

Prolific failure is a hallmark of many great inventors because they're constantly trialling new ideas. Through much trial and error of his own, Hargrave uncovered a brilliant solution to the problem of stability with his box kite. It consisted of two 3D (three dimensional) cells, with four aerofoil cross struts each. The horizontal and vertical surfaces provided the key to steady flight. Air moving over the top of the struts travelled faster than air moving below, which created lift and reduced drag. Small arched spars created a curve in the exterior surface to the same effect.

In 1894, Hargrave decided to prove publicly that his invention would fly. After calculating that four could lift his body weight (73.5kg), he tested his theory and became the first person to be lifted off the ground by a heavier-than-air device. He was able to fly steadily at over four metres above ground. This achievement provided aviation with an essential element for powered flight: a stable wing surface that provided lift. Nearly all early plane designs copied Hargrave’s. For this reason, his design would be used on many of the early aeroplanes.

Hargrave also studied various curved aerofoils (cross-sectional shapes of wings). He was particularly interested in designs with a thicker leading edge, which gave a better lift-to-drag ratio and can still be seen on modern jets today.

The Lawrence Hargrave Award is now the pinnacle of achievement in the Australian Aviation Industry, which is a fitting tribute for one of our most influential aviation pioneers.

CURRICULUM POINTERS ACTDEK043 Investigate and make judgments on how the characteristics and properties of materials are combined with force, motion and energy to create engineered solutions

ACTDEP049 Develop, modify and communicate design ideas by applying design thinking, creativity, innovation and enterprise skills of increasing sophistication

ACTDEP050 Work flexibly to effectively and safely test, select, justify and use appropriate technologies and processes to make designed solutions

ACTDEP051 Evaluate design ideas, processes and solutions against comprehensive criteria for success recognising the need for sustainability

DURATION 60 minutes

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MATERIALS Powered Flight segment from Episode 7: Airborne (video)

Powered Flight Recap Quiz (one A4 copy per student) Powered Flight Recap Quiz Answer Sheet (one A4 copy for teacher)

ACTIVITIES Warm-up (5 minutes) Begin the lesson with a short class discussion about how powered flight has affected society. Ask students to think of aspects of the global community that rely on powered flight.

Video (20 minutes) Hand out a copy of the Recap Quiz to each student. Click the link above to view the Powered Flight segment from Episode 7: Airborne. Give students five minutes to complete the quiz before going through the answers with the class.

Paper aeroplane competition (35 minutes) Give students 15–20 minutes to research and/or design up to three paper aeroplanes. Remind students to consider Hargrave’s findings on heavier-than-air flight.

1. Find an open area (e.g. a paddock or an indoor sports hall) to stage a paper aeroplane competition.

2. Hold three rounds.

3. Allow 2–3 minutes between each round for students to make improvements to their paper aeroplanes.

4. Mark the furthest three distances from each race, and award first place three points, second place two points, and third place one point.

5. Tally the points after round three to find a winner.

Homework assignment Please see the complementary Extra Activities for this lesson to assign homework based on other segments from Episode 7 of Airborne.

LEARNING OUTCOMES

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ACTDEK043 Students will have investigated how characteristics and properties of materials are combined with forces to create lift and stable flight.

ACTDEP049 Students will have developed and modified paper aeroplanes by applying design Thinking.

ACTDEP050 Students will have effectively and safely tested, selected, justified and used appropriate technologies and processes to make paper aeroplanes.

ACTDEP051 Students will have evaluated design ideas for paper aeroplanes criteria based on natural forces.

EPISODE 7: Airborne Box Kite

RECAP QUIZ

Design and Technologies Years 9–10

1. By the late 19th century, what still needed to be invented to make flight possible?

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2. The most prestigious aviation award in Australia is named after which inventor?

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3. What are the main physical challenges of heavier-than-air flight?

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4. The box kite overcame the main physical challenges of heavier-than-air flight by:

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5. How did people react to Hargrave’s attempts to get airborne using his box kites?

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6. What legacy has this invention left us?

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EPISODE 7: Airborne Box Kite

RECAP QUIZ Answers

Design and Technologies Years 9–10

1. By the late 19th century, what still needed to be invented to make flight possible? Stable and controllable flying machines that could stay airborne under their own power

2. The most prestigious aviation award in Australia is named after which inventor? Lawrence Hargrave

3. What are the main physical challenges of heavier-than-air flight? Lift must equal weight, and thrust must exceed drag

4. The box kite overcame the main physical challenges of heavier-than-air flight by: Using a clever design to create lift and reduce drag

5. How did people react to Hargrave’s attempts to get airborne using his box kites? People thought that he was crazy

6. What legacy has this invention left us? The first stable wing surface that provided lift