Chapter II: Preface

In presenting this treatise on "Aviation Engines," the writer realizes that the rapidly developing art makes it difficult to outline all latest forms or describe all current engineering practice. This exposition has been prepared primarily for instruction purposes and is adapted for men in the Aviation Section, Signal Corps, and students who wish to become aviators or aviation mechanicians. Every effort has been made to have the engineering information accurate, but owing to the diversity of authorities consulted and use of data translated from foreign language periodicals, it is expected that some slight errors will be present. The writer wishes to acknowledge his indebtedness to such firms as the Curtiss Aeroplane and Motor Co., Hall-Scott Company, Thomas-Morse Aircraft Corporation and General Vehicle Company for photographs and helpful descriptive matter. Special attention has been paid to instructions on tool equipment, use of tools, trouble "shooting" and engine repairs, as it is on these points that the average aviation student is weakest. Only such theoretical consideration of thermo-dynamics as was deemed absolutely necessary to secure a proper understanding of engine action after consulting several instructors is included, the writer's efforts having been confined to the preparation of a practical series of instructions that would be of the greatest value to those who need a diversified knowledge of internal-combustion engine operation and repair, and who must acquire it quickly. The engines described and illustrated are all practical forms that have been fitted to airplanes capable of making flights and may be considered fairly representative of the present state of the art.

VICTOR W. PAGE,

_1st Lieut. A. S. S. C., U. S. R_.

MINEOLA, L. I.,

October, 1917.

CONTENTS

PAGES
CHAPTER I

Brief Consideration of Aircraft Types--Essential Requirements of
Aerial Motors--Aviation Engines Must Be Light--Factors Influencing
Power Needed--Why Explosive Motors Are Best--Historical--Main
Types of Internal Combustion Engines 17-36

CHAPTER II

Operating Principles of Two- and Four-Stroke Engines--Four-cycle
Action--Two-cycle Action--Comparing Two- and Four-cycle Types--
Theory of Gas and Gasoline Engine--Early Gas-Engine Forms--
Isothermal Law--Adiabatic Law--Temperature Computations--Heat and
Its Work--Conversion of Heat to Power--Requisites for Best Power
Effect 37-59

CHAPTER III

Efficiency of Internal Combustion Engines--Various Measures of
Efficiency--Temperatures and Pressures--Factors Governing Economy
--Losses in Wall Cooling--Value of Indicator Cards--Compression in
Explosive Motors--Factors Limiting Compression--Causes of Heat
Losses and Inefficiency--Heat Losses to Cooling Water 60-79

CHAPTER IV

Engine Parts and Functions--Why Multiple Cylinder Engines Are Best
--Describing Sequence of Operations--Simple Engines--Four and Six
Cylinder Vertical Tandem Engines--Eight and Twelve Cylinder V
Engines--Radial Cylinder Arrangement--Rotary Cylinder Forms 80-109

CHAPTER V

Properties of Liquid Fuels--Distillates of Crude Petroleum--
Principles of Carburetion Outlined--Air Needed to Burn Gasoline--
What a Carburetor Should Do--Liquid Fuel Storage and Supply--
Vacuum Fuel Feed--Early Vaporizer Forms--Development of Float Feed
Carburetor--Maybach's Early Design--Concentric Float and Jet Type
--Schebler Carburetor--Claudel Carburetor--Stewart Metering Pin
Type--Multiple Nozzle Vaporizers--Two-Stage Carburetor--Master
Multiple Jet Type--Compound Nozzle Zenith Carburetor--Utility of
Gasoline Strainers--Intake Manifold Design and Construction--
Compensating for Various Atmospheric Conditions--How High
Altitude Affects Power--The Diesel System--Notes on Carburetor
Installation--Notes on Carburetor Adjustment 110-154

CHAPTER VI

Early Ignition Systems--Electrical Ignition Best--Fundamentals of
Magnetism Outlined--Forms of Magneto--Zones of Magnetic Influence
--How Magnets are Made--Electricity and Magnetism Related--Basic
Principles of Magneto Action--Essential Parts of Magneto and
Functions--Transformer Coil Systems--True High Tension Type--The
Berling Magneto--Timing and Care--The Dixie Magneto--Spark-Plug
Design and Application--Two-Spark Ignition--Special Airplane
Plug 155-200

CHAPTER VII

Why Lubrication Is Necessary--Friction Defined--Theory of
Lubrication--Derivation of Lubricants--Properties of Cylinder Oils
--Factors Influencing Lubrication System Selection--Gnome Type
Engines Use Castor Oil--Hall-Scott Lubrication System--Oil Supply
by Constant Level Splash System--Dry Crank-Case System Best for
Airplane Engines--Why Cooling Systems Are Necessary--Cooling
Systems Generally Applied--Cooling by Positive Pump Circulation--
Thermo-Syphon System--Direct Air-Cooling Methods--Air-Cooled
Engine Design Considerations 201-232

CHAPTER VIII

Methods of Cylinder Construction--Block Castings--Influence on
Crank-Shaft Design--Combustion Chamber Design--Bore and Stroke
Ratio--Meaning of Piston Speed--Advantage of Off-Set Cylinders--
Valve Location of Vital Import--Valve Installation Practice--Valve
Design and Construction--Valve Operation--Methods of Driving
Cam-Shaft--Valve Springs--Valve Timing--Blowing Back--Lead Given
Exhaust Valve--Exhaust Closing, Inlet Opening--Closing the
Inlet Valve--Time of Ignition--How an Engine is Timed--Gnome
"Monosoupape" Valve Timing--Springless Valves--Four Valves per
Cylinder 233-286

CHAPTER IX

Constructional Details of Pistons--Aluminum Cylinders and Pistons
--Piston Ring Construction--Leak Proof Piston Rings--Keeping Oil
Out of Combustion Chamber--Connecting Rod Forms--Connecting Rods
for Vee Engines--Cam-Shaft and Crank-Shaft Designs--Ball Bearing
Crank-Shafts--Engine Base Construction 287-323

CHAPTER X

Power Plant Installation--Curtiss OX-2 Engine Mounting and
Operating Rules--Standard S. A. E. Engine Bed Dimensions--
Hall-Scott Engine Installation and Operation--Fuel System Rules
--Ignition System--Water System--Preparations to Start Engine--
Mounting Radial and Rotary Engines--Practical Hints to Locate
Engine Troubles--All Engine Troubles Summarized--Location of
Engine Troubles Made Easy 324-375

CHAPTER XI

Tools for Adjusting and Erecting--Forms of Wrenches--Use and Care
of Files--Split Pin Removal and Installation--Complete Chisel Set
--Drilling Machines--Drills, Reamers, Taps and Dies--Measuring
Tools--Micrometer Calipers and Their Use--Typical Tool Outfits
--Special Hall-Scott Tools--Overhauling Airplane Engines--Taking
Engine Down--Defects in Cylinders--Carbon Deposits, Cause and
Prevention--Use of Carbon Scrapers--Burning Out Carbon with
Oxygen --Repairing Scored Cylinders--Valve Removal and Inspection
--Reseating and Truing Valves--Valve Grinding Processes--
Depreciation in Valve Operating System--Piston Troubles--Piston
Ring Manipulation--Fitting Piston Rings--Wrist-Pin Wear--
Inspection and Refitting of Engine Bearings--Scraping Brasses to
Fit--Fitting Connecting Rods--Testing for Bearing Parallelism--
Cam-Shafts and Timing Gears--Precautions in Reassembling Parts 376-456

CHAPTER XII

Aviation Engine Types--Division in Classes--Anzani Engines--Canton
and Unne Engine--Construction of Gnome Engines--"Monosoupape"
Gnome--German "Gnome" Type--Le Rhone Engine--Renault Air-Cooled
Engine--Simplex Model "A" Hispano-Suiza--Curtiss Aviation Motors--
Thomas-Morse Model 88 Engine--Duesenberg Engine--Aeromarine
Six-Cylinder--Wisconsin Aviation Engines--Hall-Scott Engines--
Mercedes Motor--Benz Motor--Austro-Daimler Engine--Sunbeam-Coatalen
--Indicating and Measuring Instruments--Air Starting Systems--
Electric Starting--Battery Ignition 457-571

INDEX 573

LIST OF ILLUSTRATIONS

AVIATION ENGINES

DESIGN--CONSTRUCTION--REPAIR