science

X-15 Flight 188

X-15 Flight 188 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 X-15 Flight 188 rather than just read about it. In short: X-15 Flight 188 was a record-setting test flight of the North American X-15 rocket plane on October 3, 1967. USAF test pilot William J.

Key takeaways

X-15 Flight 188 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect X-15 Flight 188 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of X-15 Flight 188 from memory before moving on to harder problems.

Reference excerpt

X-15 Flight 188 was a record-setting test flight of the North American X-15 rocket plane on October 3, 1967. USAF test pilot William J. Knight piloted the X-15A-2 hypersonic aircraft to 102,100 feet (31,100 meters) over Mud Lake, Nevada, reaching a top speed of 4,520 mph (7,270 km/h), or Mach 6.7. This remains the highest speed ever recorded by a crewed, powered aircraft.

Background The aircraft used for Flight 188 was the X-15A-2 (AF Ser No. 56-6671). This X-15 was heavily modified compared to the original X-15 specification. Originally designated X-15-2, it was damaged during landing on November 9, 1962 (Flight 74); after extensive repairs and updates, it was redesignated X-15A-2. The fuselage was lengthened by 28 inches (0.71 meters) to accommodate a liquid hydrogen fuel tank for an experimental ramjet engine mounted on the aircraft's ventral fin, which was flown but never used. Two external drop tanks containing anhydrous ammonia and liquid oxygen were fitted to increase the XLR99 main engine's fuel supply by 75%, providing an additional 60 seconds of burn time. To handle the heat of atmospheric entry at hypersonic speed, the entire surface of the airframe was covered with the Martin MA-25S ablative thermal coating; this coating was designed to char and slowly break off as the aircraft experienced aerodynamic heating, carrying away heat in the process. The thermal coating was pink in color, and a white topcoat of sealer was applied over it, giving the aircraft a notably different appearance than the other black painted X-15 airframes. The X-15A-2 was the only X-15 airframe ever fitted with the drop tanks and ablative thermal coating. Flight 188 was the 53rd flight of X-15 No. 56-6671, and the fifth flight as the modified X-15A-2 configuration.

Events of the flight Flight 188 took place on October 3, 1967. After minor problems delayed the take-off briefly, the NASA NB-52B mothership Balls 8 took off from the NASA Flight Research Center at Edwards Air Force Base, carrying the X-15A-2 under its right wing up to the planned release altitude of 45,000 ft (14 km). Balls 8 was accompanied by several F-100, F-104, and F5D chase planes, which tailed the X-15A-2 as long as possible after its release and during its landing. Once the release altitude was reached, the X-15 was released at 14:31:50 local time. X-15 pilot William J. Knight lit the XLR99 rocket engine and pulled up into a climb as the aircraft accelerated rapidly. 60 seconds after release, Knight jettisoned the drop tanks as the X-15 exceeded Mach 2 at an altitude of 70,000 ft (21 km). Now using the internal fuel supply, the engine continued to burn for a total of 140.7 seconds. Knight shut down the engine at an altitude of 102,000 ft (31 km), reaching a maximum speed of 4,520 mph (7,270 km/h), or Mach 6.7. The experimental ramjet mounted on the ventral fin disrupted airflow during high-speed flight, heating some parts of the fuselage to 2,700 °F (1,480 °C); it eventually broke away from the aircraft and was later recovered on the Edwards Air Force Base bombing range. As the X-15A-2 decelerated through Mach 5.5, an engine over-temperature warning sounded in the cockpit; Knight attempted to jettison remaining fuel from the internal tanks, but the fuel jettison system had been disabled by heat damage, meaning the aircraft's landing weight (and thus also its landing speed) would be higher than anticipated. Knight jettisoned the detachable lower fin, then safely landed the aircraft on Rogers Dry Lake at 14:40:07 local time after a flight time of 8 minutes and 17 seconds.

Aftermath The X-15A-2 was found to have sustained extensive thermal damage during the flight. Repairs were not completed before the end of the X-15 program in December 1968, making flight 188 the final flight of X-15 No. 56-6671. The aircraft was ultimately relocated to the National Museum of the United States Air Force in Dayton, Ohio, where it was refurbished and placed on permanent display. Eleven more X-15 flights were made before the end of the program; Knight would fly three of them, flights 194, 196, and 198. In 1969, Knight was awarded the Harmon Trophy by President Lyndon Johnson for his participation in the X-15 program. Flight 188 holds the airspeed record for a crewed, powered flight of a non-orbital aircraft.

Technical information Total flight time: 8 minutes, 17 seconds Burn time: 140.7 seconds Glide time: 5 minutes, 56 seconds Total distance: 342.79 km (213.00 mi) Maximum speed: 4,520 mph (7,270 km/h); Mach 6.7 Aircraft: X-15A-2 (AF Ser No. 56-6671) Total mass: 16,069 kg (35,426 lb) Dry mass: 7,766 kg (17,121 lb) Length: 15.97 m (52.4 ft) Height: 15.47 m (50.8 ft) Diameter: 1.42 m (4.7 ft) Wingspan: 6.80 m (22.3 ft) Total fuel: 8,303 kg (18,305 lb) Propulsion: Reaction Motors XLR99-RM-2 liquid-propellant rocket engine Fuel: Liquid oxygen and anhydrous ammonia Specific impulse: 276 seconds Burn time: 85 seconds on internal fuel Thrust: 262.445 kN (59,000 lbf) External drop tanks Total mass: 7,026 kg (15,490 lb) Dry mass: 902 kg (1,989 lb) Volume: 6,814 liters (1,800 U.S. gal) Length: 6.86 m (22.5 ft) Diameter: 0.98 m (3.2 ft) Additional burn time: 60 seconds on external fuel

Other X-15A-2 flights with external tanks Flight 155 – November 3, 1965, with empty external tanks, pilot Robert A. Rushworth, Mach 2.31, 5 minutes, 2 seconds Flight 159 – July 1, 1966, pilot Rushworth (last flight), Mach 1.70, 4 minutes, 29 seconds Flight 175 – November 18, 1966, pilot Knight, Mach 6.33, 8 minutes, 27 seconds, second fastest flight Flight 186 – August 21, 1967, with full ablative coating. pilot Knight, Mach 4.94, 7 minutes, 39 seconds

See also List of X-15 flights Reaction Motors XLR11

References

Bibliography Thompson, Milton O. (1992). At the Edge of Space: The X-15 Flight Program. Washington: Smithsonian Institution Press. ISBN 1-56098-107-5. OCLC 24010699.

External links

Footage of X-15A-2 Flight, POV & from B-52 & Chase Plane on YouTube Reaction Motors XLR99 Rocket – National Museum of the United States Air Force XLR-99 NASA X-15: Hypersonic Research at the Edge of Space Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane The short film Research Project X-15 is available for free viewing and download at the Internet Archive. Non-NASA X-15A at Encyclopedia Astronautica X-15: Advanced Research Airplane, design summary by North America Aviation

Illustrations

Worked examples

Example 1 — a first encounter with X-15 Flight 188

Start with the simplest possible case. Write down what X-15 Flight 188 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 X-15 Flight 188 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 X-15 Flight 188 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 X-15 Flight 188

In research: X-15 Flight 188 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 X-15 Flight 188 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: X-15 Flight 188 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1967 in spaceflight, North American Aviation aircraft, X-15 flights, so understanding it makes those chapters shorter.
In everyday life: Look for X-15 Flight 188 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 X-15 Flight 188 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what X-15 Flight 188 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 X-15 Flight 188 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is X-15 Flight 188 in simple terms?

X-15 Flight 188 was a record-setting test flight of the North American X-15 rocket plane on October 3, 1967. USAF test pilot William J.

Why does X-15 Flight 188 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 X-15 Flight 188?

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 X-15 Flight 188.