paringly, as otherwise it will take off an unnecessary amount of dope. If that will not remove the dirt, then hot water and soap will do so, but, in that case, be sure to use soap having no al

his should, if possible, be taken off while wet. It should never be scraped off when dry

aeroplane, as, otherwise, excessive skin-friction will be produced with resu

xamine them near pulleys. Removal of grease may be necessary to make a close inspection possible. If only

rol cables by smartly moving the contr

s necessary to place the aeroplane on level ground, as otherwise it may be twisted, thus throwing some wires into und

tensioned. Perhaps its opposition wire is too tight, in which case sl

and be sure that they are snaked round with safety wire, so that the l

e should be cleaned and regr

ld be carefully examined to se

er any distortion has occurred. If distortion can be corrected by the adjustment of wires, w

hedral, and stagger, and the rigging position o

es and shock absorbers. The latter, when made of rubber, wear quickest underneath. Inspect axles and skids

turnbuckles, bolts, etc. Pay particular attention to the control ca

h as pulleys, control levers, and hinge

nspection of every part, say once a week. This will take from two to three hours, according to the type of aeroplane. In order to carry it out methodically, the rigger should have a list of every part down to the sma

ind; and it is advisable to lash the control lever fast, so that th

nd, if persevered in, it is possible to become quite expert in dia

level ground, or, better than that,

edge. Their shadows can usually be seen through the fabric. Allowance must, of course, be made f

e main-plane with the tail-plane.

front strut with its rear st

the front struts. The one nearest to you should cover

main and rear spars, trailing edges,

for diagnosis of faults, but will also greatly assist in impressing upon the me

of a lot of unnecessary damage. The golden ru

be careful to stress it in such a way as to produce, as far as possible, only direct compression stresses. For instance, if it is necessary to support the lifting surface, then the packing should be arranged to come d

the undercarriage struts. If necessary to pull from elsewhere, th

floor. Any slight movement will cause the fabri

tance of protecting the outside fibres of the wood. Remember also that wood becomes distorted easily. This particularly applies to interplane strut

of this will lead to bitter disappointments in civil life; and, where Service flying is concerned, it will, to say the

art shed produces briskness, energy, and pride of work. A dirty, disorderly shed near

OS

science of aer

ht angles to its surface. Always cambered when intended to secure a reaction in one direction only. As the term "aerofoil" is hardly ever used in practical aeronautics, I have, throughout this book, used the term SURFACE,

for the practice of aviation. It really means "flyin

aerofoil with stabilizing

he rate of cha

t which the "neutral lift line

the chord of a surface makes with a lin

at which, for a given power, surface (including detrimenta

at which, for a given power, surface (including detrimenta

e at which an aeroplane ascends quickest. An angle appro

angle of incidence at which the

he path along which an aeroplane at normal flying spe

-The angle betw

aeroplane is said to be at a lateral dihedral angl

e said to be at a longitudinal dihedral angle when the projection

edral-Ditto, but substituting "c

t which the blade is inclined to the direction of motion wh

trument used for

d in miles per hour, in which case it indicates the correct number of miles per hour at only one altitude. This is owing to the density of the air decreasing with increase of altitude and nece

tion of the air causing an aeroplane

oportion of span to

hat its rotation about an axis produces a f

ng-tip, the operation of which turns an aeroplane about i

art of drivin

driver of

e charts of which can be calibrated

nt used for indicatin

its longitudinal axis (to tilt sid

surface consists of a surface or pair of wings

by two struts and wha

g spars joining the tail of a "pusher"

d tie wires to transfer a for

g surface (empennage) was mounted in front of the main lifting surface. Sometimes termed "tail-first" aeropla

at an excessive angle

r-Cur

aight line between the trailing

of the upper surface directly over it, together

ip, and through which all the air forces acting upon the surface

the longitudinal axis, and the position of which is the re

vity-The cent

situated over the fuselage, and from

ion which forms the lower part of the pilot's control lever in a

curved path is urged outwards from the centr

trolling surfaces are operated. It usually oper

The tendency to produc

tape) passing through and attached to all the ribs

nt-Change

driving through the air a surface inclined upwards and towards its direction of motion PLUS the horizontal component of th

ft produced by th

t produced by the d

drift of an aeroplane. It is convenient

ied by a current of

as to produce a speed greater

a special fluid for the purpose

volume, for instance,

ncy-Out

plane as distinct from

and V

= aeropl

Engine-Brake

ed hors

ncy, Pr

horse

r received

peller

ot-pounds. It is then only necessary to divide the upper

tail-plane, the operation of which turns an aeroplane about an axi

-See "Tai

t of coal or petroleum stores a given quantity

per surface extending beyond

of a surface relative to it

of a surface relative to it

d by dividing the stress at which a body will collapse

ne)-The proportion of

when rigging it or making adjustments. It varies with different types

ane containing the pilot, and t

ace, usually mounted at

ntal part of a rib which prev

ody heavier than air by mean

ork representing the weig

t construction of wood and fabric; and bent round detrimenta

tion upon a body. It decreases with increa

ty of water is 10 lb. per unit volume, the same unit volume of petrol, if w

lower surfaces of a biplane. In a triplane or multiplane,

in the direction of the thrust, betw

to resist bending, and to co

speed, the effect of which is a tendency to maint

n aeropl

he resistance of the air

out a vertical axis, the direction o

plan view of a body what

using a body to ga

level used for indicating the attitud

the body is disturbed, causes it to move into a posi

in the position given it by the force of a disturbance, with n

lacement of a body as distinct from res

See "Contr

be seen when viewing an aer

ich wires are taken to spar, surface, or other part of the construction in order to prevent distortion. When used in connection with a cont

by the action of driving through the air a surface

oplane can gain in a given time a

-The proportion

rofoil. Usually expressed in pounds

plied to any long spar runni

is a measure of the qu

e mass and velocity of a b

e main lifting surface consists of

fting surface consists of numerous surfaces

-Fusela

ning the engine and pilot and passenger,

of the surface is such as to make the said line coincident with the direction of motion, it results in no lift, the reaction then consisting solely of drift. Th

ll remain at rest; or, if in motion, it will move unif

akes place in the direction of the straight line in which the force acts. If a body be acted upon by several f

re is opposed an equal

ing wing design of aircraft intend

surface with an elevator placed in advance of it. Sometimes applied to the "

, to-To

application is not quite correct, since "plane" indicates

r-See "A

-screw mounted in front o

r-screw mounted behind

the propeller is mounted be

ruction from the point o

ate of

esents a force sufficient to rais

the pressure upon the piston or pistons, as distinct from the rate at which the engine does work.

of power above that necessary to maintai

the wind, which, combined with a static pressure or suction tube, is used in conj

opeller advances during one revolu

To plunge

nd opposite to the force

f which turns an aeroplane about an axis which is vertical in normal hori

n about the lon

ection within a surface. The ordinary ribs give the surface its camber

des bearing the stress of compression produced

ally used to improve the camber

e pilot. When observing an aeroplane from the front of it, the

ition of the air which may cau

moved by the pilot's feet

-See "A

lane including the propeller, but excluding the (ae

the operation of which turns an

of the air with roughness o

nce from wing-t

is forward of the lower surface when

y of a body, when disturbed, t

ertical during normal horizontal flight, and without which an

xis transverse to the direction of normal horizontal flight, and

e about its longitudinal axis, and without whic

n or tail-plane, designed to giv

angle, the result being a fall in the lift-drift ratio, the lift consequently becoming

Burden

mation produ

as a result of an exce

ways by centrifugal force w

wheels of the undercarriage are sometimes attached. Should a wheel give way the sk

with shock absorbers, situated under the tail of an aeroplane in orde

, that part of the bottom surface immediatel

iece of wood or

ched, such spar being the one situated nearest to the centre of press

ing situated at the rear of the centre of pressure and at a greater distance from it tha

ended to take merely the st

rut holding the top an

. It should be stated whether top, bottom, or side. If side,

on" when not in flight. It may also prevent the

Underca

placed as to prevent the tension of the d

similar material. Usually used in connecti

s the distance the propeller

of detrimental surface desig

To plunge

an aeroplane about its longitudinal axis in a direct

hereby the tail of

the propeller is mounted in fr

ting surface consists of three surfaces or

urface mounted at some distance behin

of which is screwed an eyebolt. Wires are attached to the eyebolts and t

peller-See

selage or nacelle, and intended to support the aeropla

e of displac

A gliding

attraction on a piece of platinum called the standard pound, deposited with the Board of Trade in London. At the centre of the Earth a body will be attracted with equ

l part of a rib which preve

vary its angle of incidence. To vary the a

f air produced by the

le of incidence of a surf

le of incidence of a surf

- or left-hand ext

autics, always known by

direction of lift, and used to prevent a su

d to the direction of gravity, and used

on of drift, and used to prevent a surfac

sion of a drift wire, and used to prevent

of the interplane strut in front of or behind it. It maintains the "stagger" an

peaking a bracing wire, is not usually described as one unless it performs the additional function of bracing some well-defined part such as the undercarriage. It will then be said to be an "undercarriage bracing lift wire." It might, perhaps, be acting as a drift wire

cing wire (usually drift or

l and situated between the top longerons of fuselate, bet

-Ditto, substituting

e side bay or centre-section side bay. This term is not usually used with reference to incidence wires, a

ion of which is diagonal from right to left w

ire preventing distortion

ontrolling surface with the pilot's

wire connecting top

e right- and left-hand top ailerons. Somet

and attached at each end to the framework. Used to prevent the wire round which it is

ent a turnbuckle barrel or other

owever, often applied to the lifting surface of an aeroplane when such surface is divid

with surfaces and models, and through which a cu

ce X dis

n mounted in front of the pilot to pr

TNO

ret

e thrust of the propellor blades, just as the shingle on the beach slips back as you ascend it. Such "give

ret

y, but having regard to the mechanical difficulties of such construction, it is a most inefficient way of securing

ret

or stalling an aeroplane an

ret

ich the lifting surfaces are raised above the pilo

ret

due to the friction of the air with roug

ret

he centre of the turn. To minimize such action the pilot banks, i.e., tilts, the aeroplane sideways in order to oppose the underside of the planes to the

ret

ash-out is combined with a wash-in to offs

ret

: Air Me

ret

he wire, and in this way the wire can make connection with the desired place by being sc

(re

rved line indicating an

(re

e propeller blades, must be equal to the speed of the aeroplane, plus the slip, and if, on account of the rarity of the air the speed of the aeroplane increases, then the angle and pitch sh

(re

s possible that extraordinary speed through space may be secured if means are found to maintain

(re

first crude fo

(re

in the Glossary at t

(re

foil" in th

(re

ace may be much nearer to the axis than is the keel-surface towards the tail. The latter may then be actually less than the surface in