Here is a concise summary of the provided text:
**Title:** The Swedish Submarine that Outsmarted the US Navy
**Key Points:**
1. **US Navy Encounter:** In 2005, a Swedish diesel-powered submarine (Gotland class) sank a US aircraft carrier (USS Ronald Reagan) in a war game, evading the carrier's anti-submarine defenses.
2. **Stealth Technology:** The Gotland class submarine's exceptional stealth was due to its innovative power generator: a **Stirling engine**, which is extremely quiet and efficient.
3. **Stirling Engine:** A 19th-century design, revamped for modern use, utilizing a closed-cycle system with a displacer piston and regenerator to conserve heat, minimizing noise and increasing efficiency.
4. **Tactical Advantage:** The submarine's silence allowed it to remain undetected by passive sonar, outperforming even nuclear-powered submarines, which generate noticeable noise from coolant pumping and leave a radiation trail.
5. **Legacy:** The Gotland class's success led to the US military leasing the submarine to develop countermeasures, and its technology has seen a resurgence in recent decades.
**Additional Context:** The summary is from an episode of "Real Engineering," sponsored by Brilliant, an educational platform focusing on problem-solving and critical thinking, with an invitation to explore their resources at the end.
Here are the key facts extracted from the text, numbered and in short sentences:
**Military and Submarine Facts**
1. The US military has the strongest and most diverse Navy in the world.
2. The US Navy's fleet of aircraft carriers makes it the second-largest Air Force in the world.
3. A single Nimitz-class aircraft carrier (e.g., USS Ronald Reagan) costs $6.2 billion.
4. The USS Ronald Reagan was "sunk" by a Swedish submarine (HSwMS Gotland) in a 2005 war game.
5. The Swedish submarine cost approximately $100 million, similar to the cost of a single F-35.
**Submarine Technology and Stirling Engine Facts**
6. The HSwMS Gotland was the first submarine to use a Stirling engine as its power generator.
7. The Stirling engine was invented by Robert Stirling in 1816.
8. Stirling engines use a closed cylinder with a fixed mass of gas to generate power.
9. The Gotland uses two Stirling engines with diesel and liquid oxygen to provide heat.
10. The submarine's generators produce 75 kW of power and can run an electric motor or charge batteries.
11. The submarine can stay submerged for up to two weeks due to its exhaust compression and storage system.
**Sonar and Detection Facts**
12. Passive sonar is used to detect submarines without emitting a "ping" that can reveal the detector's location.
13. The nationality of a submarine can sometimes be determined by the operating frequency of its power systems (e.g., 50 Hz for European subs, 60 Hz for US subs).
14. The HSwMS Gotland is designed to be practically undetectable by passive sonar.