Pilot Training: TM 1-400 Theory of Flight

Pilot Training - Theory of Flight

This part of the "Primary" is taken in large parts from a contemporary training manual being used by the US AAC/AAF in Elementary and Basic Flight Training. The title of the book is: Technical Manual No. 1-400, Theory of Flight, Prepared under direction of the Chief of the Air Corps, War Department, Washington, February 24, 1941.

This booklet has seen a number of revisions over time of course. And it is a very hard to find item in printed and original form. It is not a strictly a military or combat flying manual of course. It is about physics, aerodynamics and aircraft properties in general. The material is presented in a concise and comparatively accessible way, which makes it valuable in itself. In a way it is an airman's introduction to the "Theory of Flight".

The topics go well beyond what is required of a student, trying to qualify for a modern times PPL licence - but at the same time it is still a long way from the theory and mathematics heavy books generally expected on the topic.

Bear in mind: The booklet was published in 1941. The "theory" is based on the knowledge of these issues at the time - and more or less publicly accessible. Issues of transonic flight physics etc. are not covered. And "errors" are likely. However you will find a very readable abstract of the theories ruling the engineering behind the aircraft of the period.

If you have problems understanding some of the issues right away, pls. refer to the section "Flight Basics". If you think you want more, well the next best step would be to help yourself to a copy of: Introduction to Flight. Fourth Edition, by John D. Anderson, Jr., .Hdbnd 766 pgs: Publisher: McGraw-Hill, ISBN 0-07-109282-x, 2000

Only a part of TM 1-400 will be used here.

Table of contents:

Section I General

II Fundamentals of aerodynamics

Definition	7
Purpose	8
Distinction between airplane and other aeronautical vehicles	9
Fundamental conceptions	10
Moment of a force equilibrium	11
Velocity	12
Acceleration	13
Mass	14
Specific gravity--density	15
Standard atmosphere	16
Center of gravity	17
Graphs	18
Relative motion	19
Momentum	20
Newton's laws of motion	21
Dynamic reaction of airstream	22
Streamline flow and turbulence	23
Airfoil	24
Reaction of air upon airfoil	25
Lift and drag	26
Units and dimensional relations	27
Absolute system	28
Engineering system	29
Nature of lift	30
Pressure distribution	31
Hydrodynamic theory of lift	32
Drag	33
Wind tunnel	34

II. Airfoils

Airfoil characteristics	35
Lift coefficient	36
Drag coefficient	37
Lift-drag ratio	38
Center of pressure	39
Airfoil dimensions	40
Camber	41
Airfoil profiles	42
Aspect ratio	43
Induced drag	44
Taper	45
Airfoil tip contours	46
Airfoil selection	47
Lift coefficient criteria	48
Drag coefficient criteria	49
L/D ratio criteria	50
Center of pressure criteria	51
Aspect ratio limitations	52
Airflow stability	53
Structural adaptability	54
Operating limitations	55
Airfoil sections	56
Monoplane vs. biplane	57
Biplane pressure distribution	58
Biplane center of pressure	59
Gap-chord ratio	60
Stagger	61
Decalage	62
Landing speed	63
Variable wing area	64
Variable camber	65
Automatic slots	66
Viscosity	67
Reynold's number	68
Boundary layer effects	69

IV. Parasite drag

Skin friction and form drag	70
Parasite drag coefficient	71
Equivalent flat plate area	72
Parasite drag and model tests	73
Interference	74
Slipstream effec	75
Struts	76
Wires and tie rods	77
Fittings	78
Bare fuselage	79
Fuselage with appendages	80
Fuselage with engine	81
N. A. C. A. low drag cowling	82
Fuselage with radiator	83
Wheels	84
Retractable and detachable landing gears	85

V. Propellers

General requirements	86
Dryewiecki (Jerveski) or blade element theory	87
Propeller blade reactions under various airplane operating conditions	88
Determination of direction and velocity of airflow relative to propeller blade	89
Determination of blade angle for airfoil section	90
Thrust produced by propeller	91
Torque absorbed by propeller	92
Fixed pitch propellers	93
Controllable pitch propeller	94
Selection of best diameter for propeller	95
Efficiency of propeller	96
Advantages of three-blade propeller on geared ongines	97
Computations of blade angles	98
Advantages of controllable pitch propellers	99
Advantages of constant speed propeller	100
Comparison of performance of modern four-engine monoplane at sea level and at 15,000 feet	101

VI. Performance

Definition	102
Work and power	103
Performance calculations	104
Power required at sea level	105
Power required at altitude	106
Power available at sea lever	107
Power available at altitude	108
Maximum speed in level flight	109
Rate of climb	110
Time of climb	111
Ceiling	112
Endurance	113
Range	114
Landing characteristics	115
Take-off characteristicsr	116
Factors affecting performance	117

VII. Equilibrium, stability,and control

Reference axes	118
Angular motionr	119
Angle of incidences	110
Relative wind	111
Forces acting on complete airplane in level flight	112
Equilibrium in climb	113
Equilibrium in glide	114
Equilibrium in dive	115
Effect of throttle setting on balance	116
Definition of stability	117
Static and dynamic stability	118
Motion of airplane	119
Requirements for longitudinal stability	120
Pitching moment Curves	121