What Really Stopped the X-15 at Mach 6.7?

On October 3, 1967, Pete Knight pushes the X-15A-2 to Mach 6.7, the fastest a piloted powered aircraft has ever flown, and lands with the ablative coating burned through and metal melted under the tail. This video uses NASA's post-flight inspection records and Knight's own pilot report to trace exactly what failed: not the XLR99 engine, not control, but a shockwave colliding with another shockwave at the pylon mounting the dummy scramjet. It walks through why hypersonic heating scales with the cube of speed, why Inconel X and the MA-25S ablative coating ran out of margin, and why no wind tunnel of the era could reproduce the real speed, shape, and heating together. It also sets the record straight against two persistent myths, separating Knight's speed flight from Joe Walker's altitude flight and showing why the X-15A-2 never flew again at all. The story closes by tracing the lesson forward into the Space Shuttle's thermal protection tiles and the X-43A scramjet program. Special thanks to bohmerang and cmoreau for their incredible Boeing B-52 Stratofortress and North American X-15 Plane 3D models, generously shared under Creative Commons, which brought this video to life. 3D MODELS 3D model: "Boeing B-52 Stratofortress" by bohmerang (CC BY 4.0), sketchfab.com/models/38b0c64bd552431394efa8625d7f5144 (https://sketchfab.com/models/38b0c64bd5524...) 3D model: "North American X-15 Plane" by cmoreau (CC BY 4.0), sketchfab.com/models/bf491206ba844282949734b48b938c53 (https://sketchfab.com/models/bf491206ba844...) CHAPTERS 0:00 Intro 2:03 Part 2 4:06 Part 3 6:09 Part 4 8:12 Part 5 10:16 Part 6 12:19 Part 7 14:22 Part 8 TAGS x-15 mach 6.7, x-15 pete knight, x-15a-2, x-15 record flight, x-15 scramjet, fastest piloted aircraft, hypersonic heating, shock wave interaction heating, ablative coating x-15, inconel x, nasa x-15 history, x-15 edwards air force base, x-15 documentary, space shuttle thermal protection, x-43a scramjet, aviation engineering mystery, cold war rocket plane, michael adams x-15 crash