Inside History of the Usaf Lightweight Fighters, 1900 to 1975

By Herbert A. Hutchinson

This book, in two volumes, attempts to explain the technology developments that evolved in the period from 1900 at Kitty Hawk through the ensuing seventy-five years leading to the development of the United States F-16 Multinational Weapon System in the mid-1970s. By 2017, 4,550 F-16s, all with the first all-electric, fly-by-wire flight control system have been manufactured for use by twenty-six countries. Awestricken birds undoubtedly ask themselves, How do humans do that? as an F-16 streaks by at over two hundred times the airspeed of the bird. This book strives to provide the how-and-why answer to that fascinating story.

• Language: English
• Publisher: Xlibris US
• Release date: Oct 18, 2018
• ISBN: 9781984555748

Herbert A. Hutchinson

Herb Hutchinson is retired from a highly successful aeronautical engineering career spanning over 40 years from 1953 to 1994. After serving as an officer in the US Army in the Korean War, the initial 5 years of his engineering career were as a Wind Tunnel Test Engineer, an Aerodynamicist at Republic Aviation in New York, and Flight Test Performance Engineer at General Dynamics in Texas. The middle half of his career was as a Chief System Engineer (GS-15) for several USAF Weapons Systems, including the USAF Lightweight Fighter Program (the subject of this book) and the USAF F-16 Fighting Falcon Multi-National Weapon System, developed by the US Air Force at Wright-Patterson Air Force Base in Dayton, Ohio. Herb’s tactical call name, awarded by former F-16 pilots, is “Stuffer”. He has served as the USAF Representative on several US Presidential Advisory Committees and on USAF aircraft major accident and incident investigations. The final 13 years of his career were as a Manager of System Engineering at the Northrop Aircraft Division in California for a joint NATO Fighter Aircraft design with the Dornier Company in Germany, for the Tri-Service Standoff Attack Missile, and for the Northrop YF-23 Advanced Tactical Fighter stealth prototype (which competed against the Lockheed YF-22 ATF prototype - now the USAF F-22 Raptor). Herb graduated from the Brooklyn Technical High School (Arista), and received Bachelor of Science and Master of Science in Aeronautical Engineering degrees at Georgia Tech in Atlanta. He is an Associate Fellow Emeritus in the AIAA, a Life Member of the Veterans of Foreign Wars, and is a member of Mensa. Herb and his wife Arline reside in the Heritage Ranch (at Lake Nacimiento) section of Paso Robles, California.

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Copyright © 2018 by Herbert A. Hutchinson.

Library of Congress Control Number:      2018911711

ISBN:      Hardcover      978-1-9845-5572-4

      Softcover      978-1-9845-5573-1

      eBook      978-1-9845-5574-8

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the copyright owner.

The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.

Rev. Date: 02/13/2020

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Contents

Opening Remarks

Disclaimer

Dedication

Preface

Chapter 1 Pre-WW I Aviation Technology Developments (1900 to 1935)

Chapter 2 Pre-WW II Military Aircraft Technology Developments (1931 to 1941)

Chapter 3 Post-WW II Fighter Aircraft Technology Developments (1941 to 1950)

Chapter 4 Post-Korean War Fighter Aircraft Technology Developments (1950 to 1961)

Chapter 5 TFX (F-111), Boyd Energy-Maneuverability, Post-Vietnam War (1961 to 1972)

Chapter 6 AX (A-10) Study, FX (F-15) Study, ADF Study, USAF Prototypes Study (1963 to 1971)

Chapter 7 LWF Program Office, LWF RFPs, LWF Proposals, Technologies in LWFs (1971 to 1972)

Chapter 8 EIRT Safety of Flight, Manufacture of LWFs (1972 to 1973)

Chapter 9 Edwards AFB Joint Test Team, LWF flight tests, LWF/ACF winner, Paris Air Show (1974 to 1975)

Closing Remarks

Appendix 1 Col. John Boyd and Mr. Harry Hillaker Obituaries

About the Author

Opening Remarks

The metaphor As the twig is bent, so shall the tree grow applies to the planting of sapling trees, to people and their careers, to the technology developments of new machinery or vehicles, and most especially to each of the numerous diverse technologies embodied in military flight weapon systems (as described in this book). Shown on the front cover is a unique photograph, taken in 1975 by a USAF Aerial Photographer, of the General Dynamics YF-16 #1 and the Northrop YF-17 #1 Lightweight Fighter Prototype aircraft in the skies above Edwards Air Force Base, California. Both prototypes were engaged at the time in a combat relevant fly- off competition at the Air Force Flight Test Center. Both the YF-16 and YF-17 were winners as both were later missionized and went into multi-thousands production respectively for the USAF and USN/USMC.

The book is written in a conversational format intended to be of interest to all Readers, and tells the inside story of the events and activities that took place early in military aviation technologies history and bent the twig towards the USAF Lightweight Fighter aircraft trees. Numerous figures and photographs are shown herein and in the exact format in which they appeared in original US Government briefings, reports, and news media during the early years of the creation of small advanced technology demonstrators that went on to become The arms deal of the 20th century.

A key element interwoven into the history of the phases of development of the USAF Lightweight Fighter concept are the personalities of the LWF founding fathers (identified in the Dedication section of this book). Without their unique talents, passion for excellence, and inspired team leadership, the USAF Lightweight Fighter Program and the ensuing F-16 Multi- National Weapon System may never have existed.

Disclaimer

Much of the material contained in this book – information, dates, photographs, diagrams, charts, etc. – have been obtained from documents and correspondence generated by US Government personnel during the planning for and/or during technology development activities conducted to advance the capabilities of military flight weapon systems. There are also illustrations, diagrams, charts, tables which were generated by the two USAF Lightweight Fighter Program contractors (General Dynamics and Northrop) which were prepared for briefings to the USAF Lightweight Fighter Program Office revealing the status of their development activities required to be performed per the terms of their respective contracts with the USAF. Regardless of the source of those Government documents in the technology information database, if the document (in any format) was developed using US Government funds, the control of dissemination of the information is maintained by US Government regulatory organizations and with regulations over the content of the information to adhere to any security classifications and any release restrictions to the general public. Government documents are not controlled by the same copyright restrictions and regulations as for non-Government (i.e. commercially or privately created) documents or products, but are controlled under the US Government Freedom of Information Act of 1966 with all subsequent interpretations and modifications.

Further, much of the material is taken from the Author’s personal career memorabilia files and holdings while as a civilian employee of the US Government in the USAF at Wright- Patterson AFB, Dayton, Ohio. That material which at one time was classified up to a high level of security classification has since all been downgraded by the US Government to be Unclassified and Approved for Release to the Public under the provisions of the US Freedom Of Information Act. All such material originated by US Government activities and contained in this book is intended only for educational or informational purposes, and expressly not for the purpose of selling that material or information for financial profit.

It is known that previously published reports by authors outside Government employment about the historical development of the USAF Lightweight Fighters are not entirely factually correct and/or does not reveal a critical event happening without which the F-16 Fighting Falcon Weapon System might never have been created. The Author has published this book as a previous insider Government employee to clarify and correct that erroneous, misleading, or missing information in the historical technology development database on which the F-16 Fighting Falcon and other military flight systems relied during their respective developments.

Some of the material herein has been extracted from reference sources on the internet but only those identified as having an origin as a government document are used in this book. All of the material in that latter category that is contained herein includes photographs of military aircraft used by the United States Armed Forces and taken by personnel on active military duty. Where photographs of military aircraft are created by US military photographers and are shown, they have been copied herein for educational and visual informational transfer purposes only. The name of the producing company of the aircraft (known to be in the military inventory) shown in a photograph is acknowledged for its valued contribution to the technology database comprising military aviation history.

The Author stresses that publication of this book be considered as a not-for-personal profit venture so as to achieve maximum distribution without copyright limitations restricting it from being distributed openly to the educational/scholastic public. This book of encyclopedic nature is copyrighted by the Publisher as an entity, i.e., the book is prohibited from being copied as a whole and resold for financial profit.

As this book is not intended to be sold for personal profit, once the Author has been re-compensated by royalties from its sale for the costs expended in its publication, any further royalties from sales will be gifted to the not-for-profit Alumni Foundation of the Brooklyn Technical High School on Fort Greene Place in Brooklyn, New York, for its discretionary use toward the teaching of the technology development process in the commercial, military, or public aviation production or testing domain. The Author was a student at Brooklyn Tech in the College Preparatory Course from 1945 to 1949. It is hoped that any monetary profit will be applied by the Alumni Foundation of Brooklyn Tech to inspire and further the technical education of young students aspiring to pursue some field of science or engineering – just as Brooklyn Tech did for the Author.

There is no intentional infringement of any copyrighted material from any source and contained herein to enhance profitable gain. Any improbable infringement occurring herein is unintentional and the Author pre-apologizes for any such infringement if claimed and verified to infringe on valid copyright protection measures. The Publisher of this book is absolved of any and all proven copyright infringements that may be unintentionally contained in this book.

The Author, Herbert A. Hutchinson

Dedication

This book is dedicated most specially to:

USAF Col. John R. Boyd (and his soldiers in the Light Weight Fighter Mafia) for his creative ingenuity and persistence without which the USAF Lightweight Fighter Program may never have been brought to happen;

and to

Harry J. Hillaker for his inspired and dedicated configuration development talents applied to the USAF YF-16 Lightweight Fighter as Principal Chief Designer at the General Dynamics Corporation in Fort Worth, Texas. Harry had earlier designed the B-58 Hustler and F-111 Aardvark configurations. With professional and dedicated support from the entire General Dynamics YF-16 Lightweight Fighter development team, an aircraft labeled as the fighter pilot’s fighter was created with many major flight technology firsts. Most notable was the YF-16 being the first aircraft to fly with an all-electric (no mechanical back-up), fly-by-wire flight control system.

John Boyd and Harry Hillaker are rightfully forever enshrined in aviation history for having bent the twig of the USAF Lightweight Fighters in the right direction. A copy of their obituaries which appeared in their local news media, are provided in Appendix 1 at the end of this book. Those obituaries pay tribute to the many accomplishments both achieved in their respective careers which followed two very diverse paths until they intersected and merged to create the USAF Lightweight Fighters. The Author had the honor of having worked closely with them both to transform their conceptual ideas and design thoughts about a lightweight, highly maneuverable, affordable cost, multi-mode capable fighter aircraft as a ‘low end mix’ with the ‘high end’ F-15 Eagle into the flight-worthy USAF Lightweight Fighters.

Every F-16 Fighting Falcon in flight was, is, and continues to be a flying monument to their genius and dedicated creativity.

Preface

As the twig is bent, so shall the tree grow

That metaphor applies to the planting of sapling trees, to people and their careers, to the design of new machinery or vehicles, and most especially to each of the numerous diverse technologies embodied in military weapon systems. This book describes the As the twig is bent . . portion of that metaphor. A second book by the Author The F-16 Multi-National Weapon System, 1967 to 2017 describes the …so shall the tree grow. portion of the metaphor.

The two YF-16 twigs grew into a forest of over 4,550 F-16 Fighting Falcons in the inventory of 27 Free World countries. A second book by the Author The USAF F-16 Multi-National Weapon System, 1967 to 2017, complements the inside history of the USAF Lightweight Fighter Program to fully chronicle the F-16 success story. The two books by the Author were written with the highest of hopes that they will also inspire those Readers newly embarking on their careers in science and engineering to passionately think throughout their career – outside, and not just inside - the mythical box throughout.

The overall objective of this book is to inspire anyone contemplating whether or not to embark on a scientific or engineering career, within private industry or anywhere within the US Department of Defense, to strongly consider doing so after completion of their college education. This book is written by an Author having a more than forty years professional career divided equally as a Government employee and as an employee in private industry. The Author has the highest of hopes that this book will prove to be interesting, informative, and useful to all who may read it.

The figures and photographs shown in this book are in varying format and degree of detail, but most are presented in the exact form in which they appeared in original within Government briefings, reports, and news media during the early years of the creation of a small advanced technology demonstrator aircraft. The small aircraft later went on to become The arms deal of the 20th century as cited in the news media accounts of its successful development. A parallel hope is that this book will inspire those newly embarking on their careers in science and engineering to passionately THINK– outside, and not just inside, the mythical box - throughout their careers.

There are two statues in front of the National Archives in Washington DC. The statue on the left at the front entrance has the inscription Study the past and the statue on the right has the inscription What is past is prologue. Shown below is a photograph of each of the two statues which the Author observed while on one of many trips to the Pentagon and HQ AFSC at Andrews AFB during his many years of service with the US Government.

2.jpg

Statues at the National Archives, Washington,

D.C. (Photos by the Author)

To better understand how a new or improved technology comes into use, it is always enlightening to look back at the prior history of that technology. In a sense, it is much like developing the genealogy tree of a family ancestral history. The efforts Man has made to fly like the birds is a fascinating story that has been told in numerous books dating back to ancient Greece with the story of Daedalus and his son Icarus attempting to fly with wings made from feathers embedded in wax. This book begins much later in that aviation technology tree with a short history of the earliest activities by Orville and Wilbur Wright that led to their first successful (at least adequately if not fully) controlled flights at Kill Devil Hill near Kitty Hawk, North Carolina, on December 13, 1904. The development of aviation took a historic leap when the Wright brothers removed the barrier to understanding of flight control of an aircraft. The singular accomplishment of flight control by the Wright brothers led to technology advancements in the five primary technology domains of the five critical elements acting to determine the flight path and controlled motion of airplanes (lift, drag, propelling force, weight, and flight control). Military airplanes of a myriad of designs were subsequently developed for, during, and after the several major wars around the World in which airplanes were a key weapon of war.

In order to keep this book to a manageable size and to focus on primarily those technology developments which had profound influence on the design of the US Air Force Lightweight Fighters, it is of necessity to not detail other technologies (e.g. those that led to the carrier-capable fighter aircraft developed for the US Navy and US Marine Corps aircraft inventory). That does not infer that those technologies for naval aircraft carrier- based fighter aircraft were less important than those of land- based fighter aircraft, but only to reflect that those branches of atmospheric flight technology were not of high significance in the technology tree for that of the USAF Lightweight Fighters.

It is factual that the development of the Northrop YF-17 (later developed by the USN as the F/A-18 Hornet) was in fact derived from the same USAF Advanced Day Fighter Study done in the mid-1960s which spawned the USAF YF-16 and YF-17 Lightweight Fighter prototypes.

The two-engine Northrop YF-17 Lightweight Fighter competed in a fly-off comparison with the single engine General Dynamics YF-16 Lightweight Fighter for the USAF Air Combat Fighter Program in the mid-1970s. This competition clearly added vital database information addressing long-standing questions as to whether a two-engine fighter design is better (or not) than a single engine fighter aircraft design, such as the YF-16. Accordingly, there was no loser in the USAF Lightweight Fighter fly-off competition. The General Dynamics YF-16 went on to become the USAF F-16 Air Combat Fighter, and the Northrop YF-17 went on to become the USN/USMC F/A-18 Hornet. Both programs must be regarded as being winners.

Also, in keeping within the scope of this book and to avoid security classification requirements, there is no information included herein on the technologies of stealth, super-cruise, thrust vectoring, advanced sensor fusion, and helmet-mounted display systems that are embodied in various fifth generation jet powered fighters of the United States or other countries. Suffice it to say that the YF-16 Lightweight Fighter was the first jet fighter to fly with an all fly-by-wire flight control system and proved its advanced capabilities in flight control responsiveness for fighter aircraft agility and improved survivability when the aircraft is potentially subjected to battle damage from enemy gunfire. Flight proven fly-by-wire flight control technology is incorporated from the fourth generation F-16 fighter aircraft into integration within most fifth generation jet-propelled fighter aircraft.

For those readers, especially those newcomers to the world of aerospace engineering who wish more details about the technological history of manned atmospheric flight, the Author most strongly recommends that a book recently published The Airplane: A History Of Its Technology by the eminent aviation historian John D. Anderson, Jr. be read in its entirety. Dr. Anderson is a Curator with the National Air and Space Museum at the Smithsonian Institute and Professor Emeritus with the Department of Aerospace Engineering at the University of Maryland. His literary award-winning book is published through the auspices of the American Institute of Aeronautics and Astronautics in which he is an Honorary Fellow. [The Author is an Associate Fellow Emeritus in the AIAA.] In parallel, the internet contains a more extensive historical electronically- accessible database on military aviation technology than can be shown on paper in any book. It is from all of that military aviation history as compiled so magnificently by Dr. John Anderson and augmented with government documents used in compiling the internet database that describes the technology development paths of the first four generations of jet powered military fighter aircraft. This book selects only example technologies from each of those first four generations of US military fighter aircraft that shaped the technology database of the USAF Lightweight Fighters – the General Dynamics YF-16 and the Northrop YF-17.

A primary purpose of this book is to describe that, as in any technology development, it is the personalities who pursue the idea for advancement of an existing technology or the creation of a radically new application for a set of emerging technologies. The major technologies of military fighter aircraft are shown to also have advanced as a result of needs and capabilities to become effective against military enemy threats in the air and on the ground as demonstrated in the several wars of the past 100 years. Interwoven with the historical geopolitical events and inspired technology developments in the fascinating and unorthodox development process is the creative thinking outside the box done by a small group of professionals whose scientific and creative DNA were merged into developing the USAF Lightweight Fighters.

The contents of this book place emphasis on the genealogy of the technologies that were selected for inclusion in the initial designs for the Lightweight Fighter configurations as advanced technology demonstrator aircraft. Accordingly much emphasis was placed by both General Dynamics and Northrop on those technologies improving the state of the art in maneuverability of the fighter aircraft and desirements (i.e. desired capabilities rather than contractually specified required capabilities) which a few different organizations within the USAF had expressed to the aircraft industry during many USAF IR&D (Independent Research and Development) programs. Northrop focused their efforts on a fighter that would replace their F-5 series of fighter aircraft, noted for being small (light weight), low-cost, and for being a contender for the Foreign Military Sales acquisitions by other free-world nations. General Dynamics read the tea leaves slightly differently than did Northrop and focused their IR&D activities on the several technologies in the areas of configuration aerodynamics and flight control systems that were emerging from the technology developments fostered by the USAF laboratories at Wright-Patterson AFB. That database of information was augmented with cooperative wind tunnel tests and data analysis provided by the wind tunnel test experts at the several NASA research centers (at Langley Research Center, Virginia; at Ames Research Center, Mountain View, California; and at Lewis Research Center, Cleveland, Ohio.)

Both General Dynamics and Northrop had also applied Lessons Learned from air combat and ground support activities in the Korean War and the Vietnam War against the principal threat aircraft – those created by the Soviet Air Force for its inventory as well as for the inventories of those of Communist bloc countries aligned with the Soviet political and military Cold War objectives. Those Lessons Learned all pointed to the need for future fighter aircraft to have a high degree of Survivability and low Vulnerability built into the design from the start – not added as later upgrades (as was done for the F-4s being lost at an alarming rate to ground gunfire in Vietnam). The same need was foreseen in the areas of Reliability, Maintainability, Reparability, and Serviceability to maintain the inventory of fighter aircraft at a high state of readiness and availability when based at far-flung operational bases. Those capabilities also must be included as initial design parameters, and not relied upon for being accomplished later as upgrades.

In Appendix 1 at the end of this book can be found the biographies and obituaries of two key individuals without whom the USAF Lightweight Fighters may not have proceeded beyond being another interesting flight demonstration of advanced flight technologies embodied in a prototype platform. Only after a weapon system has entered the operational inventory and performed well for a few years in hazardous operational environments do the talents of the initial team developing the weapon system from its inception become recognized and commemorated. Aspiring young engineers reading those biographies should note that no one career path is the same as another. They should also note that when those several diverse careers are woven into a team effort, it is that team effort that determines the degree of success of a new aircraft design having outstanding performance characteristics.

There have been several outstanding books and numerous aviation magazine articles written during the past 40 years describing the successful prototype approach taken during the Lightweight Fighter phase of the F-16 Program, and would make this book seem to be redundant. However, those books were written by authors referencing official program documents in USAF reports to Congress which typically show only achieved progress milestones and schedules. This book is written by the USAF Chief System Engineer who was there and did that every step of the way for six fascinating years in the Lightweight Fighter and F-16 Air Combat Fighter Program Offices. While the role of the USAF Chief System Engineer is not as vital to the creation of an advanced technology demonstrator version of a weapons system concept, the responsibilities for transitioning that advanced technology demonstrator prototype into a fully operational capable weapon system is a huge challenge and responsibility given to the entire development team. A number of unusual problems surfaced during the USAF Lightweight Fighter Program, and many of those more significant problems and resolutions are described herein to portray the types of unusual circumstances that arise when integrating a set of new technological advances into any new aircraft design.

It should be noted to newcomers to technology development activities that it is of paramount importance when solving a technological problem that it is necessary to not only include the dominant independent and dependent parameters within that technology, but important to also consider the interfaces (physical and functional) of that technology with adjacent technologies and design features. Another most important factor to be considered is the exposure of the technology to very harsh operational environments much different from that in controlled laboratory environments. Woven into the technical and engineering aspects of the USAF Lightweight Fighters design is the human influence on requirements definition, setting of goals and schedules, management approaches, creating sources for funding, and a multitude of considerations inherently involved in every new design development.

Every new flight system development begins with baselining the state of the art in the technologies that exist at the start of the new development and that baseline is heavily influenced by the experience with the most recent preceding aircraft used extensively in a preceding war. The baseline of the technologies described herein are understandably not taught in significant depth and detail in engineering colleges and universities, and are included herein primarily to educate and inform those who surely will be confronted with similar surprises and challenging problems in their new career paths for advancing flight technologies of the next generations of turbojet-propelled military aircraft.

It is commonly accepted that the next war will not be fought just like the previous war. It is the wisdom and hindsight/foresight of program managers, requirements definition personnel, technology creators and developers, creative designers, and engineering personnel acting as a team in developing the next weapon system for that next unknown war. Teamwork is hard to define, but it is much like the water in a mix of concrete. It is unseen water which produces the strength of the mix – without it the mix crumbles. Also commonly accepted is that there is no crystal ball which will prognosticate where, when, and how that next war will be fought. Based on the history of fighter aircraft aviation, the only assurance is that regrettably there will be a next war, and the losses of life and equipment on both sides are inevitable. In general, the winner of a war is that country which suffers the least losses of human lives and war equipment.

The readers of this book should bear in mind that when John Boyd created the concept of a multi-mode lightweight low-cost fighter in the early 1960s, he had no information predicting that there would be a war in Bosnia, or Iraq, or Afghanistan. It was the foresight of the General Dynamics Chief Designer Harry Hillaker who developed the set of advanced technologies (that were emerging from USAF Research Laboratories based on needs and changes in capabilities derived from battle damage assessments of the F-4 Phantom II in the Vietnam War) to be applied to the General Dynamics Model 401 design identified later as the YF-16 in the USAF Lightweight Fighter Program. The prime example of Harry Hillaker’s foresight was in his selection of the Survivable Flight Control System technology developed to reduce the losses of fighter aircraft to enemy ground gunfire. Those survivability needs led to implementation of the YF-16 all- electric flight control system which became more commonly known as the fly-by-wire system. Fly-by-wire dictated the use of a central flight control computer with quadraplex (4) channels for redundancy (i.e. Survivability) – and that in turn provided the flexibility for integrating flight control algorithms with advanced targeting and weapons delivery controls and displays. More details of this appear later in this book and are surfaced here summarily to provide readers with the need to recognize that there is much need to think outside the box when selecting a technology for one purpose and finding it to have beneficial (synergistic) effects when combined/ integrated with other technologies in the same flight platform. Conversely, there must be constant analysis and testing done to assure that incorporation of one technology does not degrade or nullify the benefits of an allied technology on the same platform.

As the chapters to be read hereafter describe, development of a typical new technology goes through phases of development before being integrated with allied technologies into the system design. The readers of this book who have little interest in this process should optionally skip to the last page of this Preface.

This was the same general process which was heuristically developed by the Wright brothers for their Wright Flyer Prototype in the early 1900s and which has been used as a management template in almost every aircraft-related technology development up through that of the F-16 Fighting Falcon Weapon System.

1) The initial phase consists of conducting a survey of that technology domain to ascertain whether it is a technology development with merely an academic-driven basis (the hardest kind to find sources of funding to continue), or to determine if there is a potential high payoff justifying taking the risk for that technology to be applied to a much-needed system (which typically enjoy high priority and receive adequate funding for development).

2) The next logical phase is to analyze the past efforts, if any, in the development of that technology to ascertain the development status of the technology as well as to apply the Lessons Learned from previous development failures experienced with earlier attempts in its development. This phase also includes planning of laboratory testing to establishing the baseline status of the potential new technology or improvements to a previously existing but not fully developed technology. This phase is commonly referred to as the Baselining Phase, defining what is essentially the starting point (often referred to as a scratch in the mud) from which the technology to be developed progresses.

3) The third phase is to conduct exploratory laboratory tests and analytical studies leading to development of a more comprehensive ground test and analysis plan for obtaining a quantified initial estimate of the relative importance of the independent and dependent variables associated with the technology. It is common to test the unknowns (Unks) in the technology, but it is also common to encounter unknown unknowns (Unk Unks) inherent with the new technology. Neither Unks nor Unk Unks are ever to be ignored.

4) The ground testing phase (wind tunnel tests, structural tests, electrical and electronics functional tests, software validation tests, etc.) is conducted next to define the envelope within which the technology is capable of operating and to identify those regions where the potential technology is either highly advantageous or disadvantageous to have when applied to a system prototype design;

5) The flight test phase of a prototype (if schedule and funding permits) is the preferred next phase for flight demonstrating that technology (or set of allied technologies) with the objective much like that of earlier ground tests. That objective is to define the envelope limits and constraints (if any) for applying that technology, and to verify with flight data the degree to which that technology has on the advantages and disadvantages when integrated as a subsystem into a flight demonstrator or prototype.

6) Regardless of whether all or only some of the previous phases are conducted, the definition of the risk status and payoff potential of the technology must be thoroughly documented and analyzed to include identification of residual unknowns, risk potential, payoff potential, and with cost estimates as realistically as can be forecasted. These results are then presented as options to the design team management and program management for (a) applying and integrating that technology with other allied technologies, or (b) deferring that technology to a future system design, or (c) at worst, abandoning further development and consideration of that technology;

7) The preferable last technical phase is to conduct flight testing of a pre-production prototype platform, with allied technologies integrated into the platform as a system, with a goal of verifying to what degree the estimated full payoff of that technology development activity has been achieved. Often an isolated technology will have been demonstrated fully in ground testing, but when integrated with other allied technologies in the demonstration platform may net an exceedance of the sum of the benefits of the individual technologies (i.e., a synergism). Similarly, there may be realized a net reduction in the sum of the allied technologies when integrated and evaluated as a total system (i.e., a detriment).

To determine when each phase has been adequately accomplished for readiness to proceed with the next phase, it is common practice to establish a Progress Milestone for the completion of each phase. A Progress Milestone differs from a Schedule Milestone in that a Progress Milestone is no defined to be completed by a specific calendar date, but instead is a milestone indicating accomplishment of a successful test regardless of the date of conduct of the test. The completion criteria for each Progress Milestone should be complete, be realistic, and be well defined. In practice, it is common for the Procuring Agent and the Contract Performing Agent to use those Progress Milestones also as a basis for incremental payment of funds for the contract effort, such that the Progress Milestones are important indicators of the technical progress, the budgetary/expenditures aspects of the contract, as well as for overall program progress when the status of the program is reported to the Contracting Program Office.

When presented with only an artist’s rendition or a photograph of a test model but not a photograph of the end product incorporating that technology, viewers should not assume that the technology development process as outlined above has been developed to a totally successful degree of completeness by that design team. The urgency of a technology improvement need and a set of design requirements obtained as feedback from dynamically changing event(s), such as those that are frequently identified from operational combat battles and/ or foreign technology updates, may require modification in planning. Unfortunately, some steps in the process may be short-cut, and the schedule and costs for some steps in the process to be accelerated, altered, or perhaps some steps may be deferred because of program urgency requirements and/or funding availability. That is when technology developers do the best that can be done with available resources – leading to the development team having to use much resourcefulness. The Contracting Program Office must always be kept informed and in the active loop when planning and schedules/costs changes are being considered.

For those Readers who are planning to be employed as engineering interns or junior engineers and to be assigned to an on-going technology or system of technologies development activity, their value to the program will be determined by the timing of their employment relative to which phase identified above and at a time relative to a completed Progress Milestone. Regardless of which phase exists or is underway at the time of his/her employment, the new employee (engineer or technician) is well advised to rapidly become familiar as to what is the status (i.e., what has already been accomplished) in that technology or system of technologies.

A diagram (commonly referred to as a Learning Curve) will often be generated to graphically orient those readers who may be interested as to how Program Management tracks progress as each phase of the program unfolds. This type of diagram, supplemented with dozens of other management plans and schedule, is commonly kept in a Program Control Room and kept up to date with periodic (bi-weekly or monthly) updates. Milestones which are slipping are marked in red. An actual achieved Milestone is marked in green on the chart when the Phase is completed. The Program Management at both the Performing Contractor facility and at the Contracting Program Office can better visualize how each of the major elements of the Program is progressing in their development according to the planned schedule. When hot spots are identified they are typically given closer attention, especially if it requires additional tests of some type to address an unknown (an Unk) which has surfaced unexpectedly during a test. The more troublesome type surprises to accommodate are the emergence of unknown unknowns (the Unk Unks) for which planning schedules and funding changes must be adjusted in a logical and affordable work-around manner.

An example of what a typical Progress Tracking and Planning Chart looks like in the technology development and program management process appears next:

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Tracking Progress In Technology Development

(Example) (Source: The Author)

As shown in the diagram above, not until the latter part of Phase 6 when the technology is detail designed and integrated with allied technologies are design conflicts identified. Not until Phase 7 Flight Tests on a pre-production prototype will those conflicts be quantified with actual flight test data. On the positive side, there may be synergistic results identified during the design integration that also are quantified by flight test data on the pre-production prototype. Seldom does it occur that there are neither detrimental nor synergistic effects emerging during the design integration and flight testing.

Having previewed as to what is, and what is not, in this book and why, it is now time to read a book which describes the technology advancements achieved and the unusual events that took place in the development of many exceptionally well- designed aircraft and weapon systems responding to major events that have occurred in the intriguing history of military aviation since the Wright brothers. Not all weapons systems programs meet with success when integrated with other aircraft in the same operational inventory and are sent back to the drawing board. The experience base and pattern of thought used by a few highly creative and analytical individuals are cited in this book as creating major new technology developments and/or its application to a new aircraft design that had significant high pay-off despite high risks taken during their development.

Readers should note that there is much photographic content in this book. Anyone developing a new technology should photographically record test set-ups, instrumentation type and installations, models (of all scales) being tested, and test facilities being used such that when the inevitable surprise in the test data recorded is revealed, or failure of a component of the test model should happen, it can be more rapidly investigated to determine the root cause. Numerous photographs, augmented by other visual exhibits, will be used to not only visually describe the progress made in the development of the USAF Lightweight Fighters but to also visually describe the actual problems encountered and surprise results of tests conducted while developing its capabilities.

The first chapters of this book (Chapter 1 through Chapter 4) describe fighter aircraft development history – from the Wright brothers’ achievements in aircraft flight technologies, World War I, World War II, the onset of the Cold War with the Soviet Union, the Korean War 1950-1953, and through the end of the 1950s decade. Those Readers who are familiar with that aviation history and wish not to repeat that history should feel free to skip over that history in Chapters 1, 2, 3, and 4 and should start reading at Chapter 5 to be exposed to those few key events and identification of key personnel which combined and created the concept of the Lightweight Fighter for the USAF. Chapters 5 through 7 are dedicated to describing in substantial detail how the multi-mode General Dynamics YF- 16 and Northrop YF-17 Lightweight Fighters came to be, but almost did not (for non-technological reasons).

Appendix 1 at the end of this book describes the biographies (and obituaries) for two key individuals credited with creating the USAF Lightweight Fighters. This book has been dedicated to them for their professionalism and loyalty to their country without seeking or expecting any large monetary reward for their dedicated efforts. Readers who are newly embarking on a career in technology development, and especially a development activity in which other professionals of varying levels of experience and specialties are teamed in developing an entirely new, or major modification of an existing, military weapon system, will gain much from observing how the team works together. As Col. John Boyd’s career was entirely within the USAF and Harry Hillaker’s career was entirely within the aircraft design, test, and manufacturing environment of Government Contractors, their obituaries describe what are the variety of assignments and challenges as well as opportunities that will be presented during the career of a professional engineer within Government or private industry employment.

It would be difficult to portray this book with a one or two word descriptor such as a documentary, a non-fictional novel, a technical report, or a historical summary – it is a mélange of all of those and with a few Author’s Notes injected randomly to clarify an event or to tell a humorous anecdote about the personality of a person. All of the personalities mentioned in this book are no longer alive to challenge those quotes, but since the quotes are all of a complimentary nature the Author felt they would not object.

The Author chose his career to be half within the employ of large airframe manufacturing companies (designing and/or testing aircraft to meet Government contract requirements), and half within the employ of the US Air Force as a civilian engineer – in Federal Civil Service. Having served in the US Army in the Korean War time period added a third dimension to the Author’s background in gaining a hands-on appreciation of how and why the military services generate the need for an item in their weapons inventories.

The developments and technology advances described in this book occurred mostly before the Author became an active participant in those earlier developments, although some of the events such as the Japanese aircraft attacking the US Naval warships at Pearl Harbor on December 7, 1941, are still stored in the memory of a pre-teenager forming a calibration of what the World is really like – not as ideally as taught in elementary education textbooks. The contents in the early chapters (1-4) of this book are mostly obtained from historical records in military aviation history, and are as interpreted in perspective of their influence on technologies emerging as Lessons Learned from previous wars.

The contents in the latter chapters (5-9) of this book were obtained primarily from the two contractors – General Dynamics and Northrop – providing material to the USAF Lightweight Fighter Program Office files. That material was supplemented with personal memorabilia from the Author’s Pack Rat file. Some material was taken from Government documents (technical reports, briefings, weekly status reports, etc.) generated either by the two Contractors and provided to the USAF Lightweight Fighter Program for tracking progress of design, analysis, or test activities, or generated by USAF personnel for presentations to be given by the USAF Lightweight Fighter Program to higher headquarters or to other USAF organizations (e.g. the USAF Research Laboratories). Within the USAF Research Laboratories, flight technologies are developed to maintain a constant awareness of how foreign and domestic technology developments are progressing. All such references and all photographs, documents, charts, diagrams, etc. have been declassified (if originally classified), have been Approved for Public Release, or are in the photographic files of the military services on the internet and released under the provisions of the Freedom Of Information Act FOIA.

This book is intended to be only an educational, informational transfer of material and information describing the status of technologies of military fighter aircraft design, as well as to provide career guidance based on actual highly successful careers. The Disclaimer at the front of this book should be read carefully before any information is extracted from this not-for- personal-profit book.

Chapter 1 Pre-WW I Aviation Technology

Developments (1900 to 1935)

For Readers to better understand and more fully appreciate what actually takes place in the development of any new aircraft, the genealogy (documented history) of the technologies being considered for application to and integration in the new aircraft development should be very thoroughly researched. The fewer the Unks and the more the knowns are discovered, the prospects are increased for developing the new technology. Unlike the genealogies of humans however, it is not a backward tracing process starting with the birth parents of the individual being traced and determining from Public Record documents their parents, grandparents, great grandparents, and so forth until the document trail can be traced no further. Technology genealogy is better described by identifying the original idea for the technology as a concept, then describing the events and personalities involved in developing that technology from its birth as a concept, and then describing that concept as it matures into hardware (and software) in practical, useful applications.

This book has the ultimate goal of showing in generally chronological order the evolution of the multiple technologies that were developed individually and then merged later into development of the USAF Lightweight Fighters.

Initially, it was considered to start this book at the point where jet engines had just emerged in the aviation technology data base; however, it was then felt that Readers might derive additional benefit by starting this book at an even earlier period in time (i.e., for the ancestral roots of the technologies that are in the USAF Lightweight Fighter genealogical history). It was then decided that a better starting point for this book would be two decades prior to the start of the 20th century. It was in the 1880s that other scientists and inventors were performing scientifically credible experiments to learn how to fly like the birds. It is from that foundation in knowledge and experiences that the Wright brothers, Orville and Wilbur, were inspired to conduct their own exploratory tests with glider aircraft to understand how birds were able to control their flight path to get from

Reviews for Inside History of the Usaf Lightweight Fighters, 1900 to 1975

[Ebazer Khairetdinov · Rating: 5 out of 5 stars]

Very interesting book for all who love military aviation history.