AIRCRAFT of the UNITED STATES, VOLUME TWO

PREFACE

THE general scope of Aircraft of the United States and the basis of classification used in this work, as also in the two companion volumes British Aircraft, are here briefly recapitulated for the convenience of readers who are not familiar with the earlier books.

Together with the first part, which was recently published, the present volume is intended to form a concise pocket reference to the principal types of aircraft built in the United States during the past decade.

Though chiefly designed for the use of members of Allied Forces and their auxiliary services, for whom aircraft recognition will continue to be an essential study, it is hoped that these small books may also prove acceptable to a wider and increasingly air - minded public.

The period of ten years or so selected for review embraces the design and development of practically all types of American aircraft flying today. it witnessed the steady peacetime growth of civil aviation and the sudden urgent and fantastic expansion of the war years. It has seen the general adoption of retractable undercarriages, the transition from biplanes to monoplanes ; and a three - fold increase in the output the most powerful engines. The same decade has brought within sight the widespread commercial use of the helicopter and has revealed the amazing possibilities of jet propulsion.