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Laydown delivery

Laydown delivery is a physics 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 Laydown delivery rather than just read about it. In short: Laydown delivery is a mode of delivery found in some nuclear gravity bombs: the bomb's descent to the target is slowed by parachute so that it lands on the ground without detonating. The bomb then detonates by timer some time later.

Laydown delivery — main illustration
Laydown delivery — illustration

Key takeaways

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

Reference excerpt

Laydown delivery is a mode of delivery found in some nuclear gravity bombs: the bomb's descent to the target is slowed by parachute so that it lands on the ground without detonating. The bomb then detonates by timer some time later. Laydown delivery requires the weapon to be reinforced so that it can survive the force of impact. Laydown modes are used to make weapon delivery survivable by aircraft flying at low level. Low-altitude delivery helps hide the aircraft from surface-to-air missiles. The ground burst detonation of a laydown delivered weapon is used to increase the effect of the weapon's blast on built-up targets such as submarine pens, or to transmit a shock wave through the ground to attack deeply-buried targets. An attack of this type produces large amounts of radioactive fallout.

Weapons with laydown delivery options

United Kingdom The issue of aircraft survivability led to laydown being selected for the Vickers Valiant bomber of the Royal Air Force, as the design became increasingly vulnerable to Soviet weapons, especially the SA-2 missile. The low-level laydown delivery was referred to as "Equipment 2 Foxtrot" in RAF parlance; alternatives included "2 Echo" toss bombing and "2 Hotel", a particular climbing delivery method used by the Avro Vulcan.

United States B28 bomb — Only in the RE (retarded external), RI (retarded internal) and FI (full-fuzing internal) versions of the weapon. The RE and RI versions of the weapon used the W28 mod 1 warhead and were an interim weapon only capable of laydown delivery at 2,000 feet (610 m) altitude, while the FI version using W28 Mod 2 and later warheads was capable of 500 feet (150 m) delivery. B43 bomb — Both variants had laydown capability. B53 bomb — Full-fuzing option (FUFO) weapon with laydown. The weapon later lost FUFO in its B53-1 upgrade in 1988, having only laydown fuzing. B61 bomb — Full-fuzing option (FUFO) weapon with laydown. Capable of laydown delivery at 50 feet (15 m) altitude. B83 bomb — Full-fuzing option (FUFO) weapon with laydown.

See also Air burst Toss bombing Nuclear bunker buster

References

Illustrations

Laydown delivery: Mark 39 Mod 2 thermonuclear weapon, as found by the explosive ordnance disposal team after the Goldsboro accident in 1961.
Mark 39 Mod 2 thermonuclear weapon, as found by the explosive ordnance disposal team after the Goldsboro accident in 1961.

Worked examples

Example 1 — a first encounter with Laydown delivery

Start with the simplest possible case. Write down what Laydown delivery claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, 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 Laydown delivery 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 Laydown delivery 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 Laydown delivery

In research
Laydown delivery appears in physics 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 Laydown delivery 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
Laydown delivery is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aerial bombing, Aerial warfare strategy, Military aviation stubs, so understanding it makes those chapters shorter.
In everyday life
Look for Laydown delivery 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 Laydown delivery in 20 minutes

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

Frequently asked questions

What is Laydown delivery in simple terms?

Laydown delivery is a mode of delivery found in some nuclear gravity bombs: the bomb's descent to the target is slowed by parachute so that it lands on the ground without detonating. The bomb then detonates by timer some time later.

Why does Laydown delivery matter?

Because it connects several physics 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 Laydown delivery?

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 Laydown delivery.

Tags

  • Aerial bombing
  • Aerial warfare strategy
  • Military aviation stubs
  • Nuclear weapon stubs
  • Nuclear weapons

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