The X-15 is the rocket plane that ushered in the Space Age in the 1960s

X-15_-1_Pilot_Neil_Armstrong_onthegroundThis new book is a biography of the North American X-15 and the program’s 199 flights. There are technical aspects as there are descriptions of the records obtained in the X-15 but there is so much more in this colorful book which has it differ from previous books on this aircraft.

Anderson (Curator of Aerodynamics NASM) and Passman (also with the NASM and was influential in the X-2 and X-16 programs) have written the X-15’s bio so that we can understand the unique niche these three aircraft (X-15-1, X-15-2 and X-15-3) created and still solely occupy.

The X-15 was built to burn and to burn through the atmosphere into near space – to explore a performance envelope no other aircraft had experienced. Though missiles briefly travel hypersonically they do not return in the same piece as which they were launched so the rocket powered X-15 would be a pioneering aircraft design.

The X-15 design proposal request called for an aircraft which could fly in the hypersonic flight regime to gather data for future aircraft designs but also fly transonically as well as subsonically. Anderson and Passman write well how challenging this request was given the lack of wind tunnel data for flying at hypersonic speeds as well as developing materials to survive in the high temperature environments above Mach 2.

Anderson and Passman provide short bios of each of the twelve pilots who flew the X-15 as well as describe mission planning (including staff required for up to five alternate airfields), Iconel X (an alloy required for the surface of each X-15 which could maintain its strength up to Mach 7) as well as the aircraft’s design.

Intuitively, one may expect a hypersonic aircraft to be at least as sleek as the Mach 2 Lockheed F-104 Starfighter but the authors clearly and easily explain why the X-15 had to be more blunt and more stubby- as well as the finer design points of the wings, rolling tail and vertical surfaces.

The engines are also nicely addressed as is the major rebuild of the second X-15 to the X-15A-2 configuration with the 29-inch fuselage extension and exterior saddle tanks added to carry additional fuel.

Along the way we also learn the X-15 had not one, not two but three joy sticks and why. We also learn of the prehistory to hypersonic flight by the team of Woods and Dornberger as well as Stack and another, Kotcher. Nearly 200 photos are within the book, 175 to be exact, and compliment the text though the captions are written with economy.

Descriptions of the record breaking maximum speed flight (Mach 6.7 piloted by Pete Knight) as well as the maximum height flight (347,800 feet piloted by Joe Walker) are presented. Pilot histories are included – several of which are even more remarkable than one might anticipate. Interestingly, the book has a tabulation of flight times at each Mach number obtained.

The book is a joy to read and to learn of the nine years the X-15 flew, usually for about 10 minutes and covering no more than 300 miles during each flight. Amazingly, the average flight had the X-15 flying under power for 90 seconds, then following a ballistic trajectory, then once again flying but as a glider.

The authors also neatly illustrate the work done by the pilots who followed a precise flight plan on each mission and were challenged to learn on the fly, in a matter of minutes, how to pilot the X-15 whenever a design change was made.

Smaller than a coffee table book yet too large for an airline seat table/tray this book is well written by authors who know the material but, more importantly, know the esteemed place in history occupied by the North American X-15. Anderson and Passman recall the starts, the activities and the accomplishments of the X-15 program which generated a unique data set still in use five decades after the 199th and final X-15 flight.

Today is the release date for this remarkable book about this extraordinary aircraft – written by knowing authors who love what they wrote about.