science

Laddermill

Laddermill is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Laddermill rather than just read about it. In short: A laddermill kite system is an airborne wind turbine consisting of a long string or loop of power kites. The loop or string of kites (the "ladder") would be launched in the air by the lifting force of the kites, until it is fully unrolled, and the top reaches a height determined by designers and operators; some designers have considered heights of about 30,000 feet (9,100 meters), but the concept is not height-depen…

Key takeaways

Laddermill belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Laddermill to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Laddermill from memory before moving on to harder problems.

Reference excerpt

A laddermill kite system is an airborne wind turbine consisting of a long string or loop of power kites. The loop or string of kites (the "ladder") would be launched in the air by the lifting force of the kites, until it is fully unrolled, and the top reaches a height determined by designers and operators; some designers have considered heights of about 30,000 feet (9,100 meters), but the concept is not height-dependent. The laddermill method may use one endless loop, two endless loops, or more such loops.

Introduction In a 2007 "road map" report on renewable energy adopted by the European Parliament, laddermill technology was listed among various "promising and challenging" new energy sources into which revenue from emissions trading could be reinvested.

Operating modes There are currently two operating modes considered:

The kites pull up the long string on which they are tethered, and the resulting energy is then used to drive an electric generator. When the end of the string is reached the pull force of the kites is reduced by changing the angle of attack of the kites "wing shape", and the string is then rewound with the electric generator acting as a motor, or by other means. If the string is reduced to its minimum length the next energy generating cycle is started by restoring the angle of attack of the kites to maximum lift. Kites on one side of a wire loop generate lift while the ones on the other side do not because the angle of attack of the kites "wing shape" changes when the kite passes the top of the loop. So the kites pull up only one end of an endless loop, causing the loop to start to rotate, and the resulting released energy is then used to drive an electric generator.

Design A "rotating loop" "LadderMill" project was designed and developed by the Dutch ex-astronaut and physicist Wubbo Ockels. As quoted from his website:

The LadderMill is the response to the challenge for exploiting the gigantic energy source contained in the airspace up to high altitudes of 10 km. The concept has been developed with the aim to convert wind energy at altitude in electricity on the ground in an environmental and cost effective manner.

References

External links The laddermill website of Wubbo Ockels. Website of the Delft University of Technology explaining the principle of the LadderMill project. paper "Design and Construction of a 4 kW Groundstation for the Laddermill". Giant kites to tap power of the high wind Alok Jha, The Guardian, Sunday August 3, 2008

Worked examples

Example 1 — a first encounter with Laddermill

Start with the simplest possible case. Write down what Laddermill claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Laddermill before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Laddermill ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Laddermill

In research: Laddermill appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Laddermill in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Laddermill is common in secondary-school and first-year university syllabi. It links to neighbouring topics Airborne wind power, Aircraft engines, Kites, so understanding it makes those chapters shorter.
In everyday life: Look for Laddermill outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Laddermill in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Laddermill means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Laddermill out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Laddermill in simple terms?

Why does Laddermill matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Laddermill?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Laddermill.