Transcriber’s Notes: Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Equal signs “=” before and after a word or phrase indicate =bold= in the original text. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Typographical and punctuation errors have been silently corrected. TRACTOR PRINCIPLES THE ACTION, MECHANISM, HANDLING, CARE, MAINTENANCE AND REPAIR OF THE GAS ENGINE TRACTOR BY ROGER B. WHITMAN AUTHOR OF “MOTOR CAR PRINCIPLES,” “GAS ENGINE PRINCIPLES,” “MOTOR-CYCLE PRINCIPLES,” ETC. [Illustration] FULLY ILLUSTRATED D. APPLETON AND COMPANY NEW YORK LONDON 1920 COPYRIGHT, 1920, BY D. APPLETON AND COMPANY PRINTED IN THE UNITED STATES OF AMERICA FOREWORD The tractor of to-day is built in almost as many types and designs as there are tractor makers, and is far from being as standard as the automobile. There are tractors with one driving wheel, with two driving wheels, with three and with four, as well as three arrangements of the crawler principle; there are two-wheelers, three-wheelers and four-wheelers; tractors that are controlled by pedals and levers and tractors that are driven by reins. Thus if a man who is competent to handle and care for one make is given another make to run, he may be entirely at a loss as to how it works and how it should be handled. It is the purpose of this book to explain and describe all of the mechanisms that are in common use in tractor construction, to the end that the reader may be able to identify and understand the parts of whatever make he may see or handle. CONTENTS PAGE CHAPTER I TRACTOR PRINCIPLES Comparison between tractors and automobiles—What is required for each—Advantage of understanding the mechanism—No standard tractor design—Principal parts of a tractor—Necessity for each 1 CHAPTER II ENGINE PRINCIPLES Power attained from heat—Combustible mixture—Principle of engine operation—Combustion space—Gas engine cycle—Dead strokes—Flywheel—Starting an engine—Inlet stroke—Compression stroke—Importance of compression—Ignition—Advance and retard of ignition—Power stroke—Exhaust stroke—Production of power—Vertical and horizontal engines—Firing order 9