The aeroplane should be standing upon level ground, or,
better than that, packed up into its ``flying position.''
Now stand in front of it and line up the leading edge
with the main spar, rear spar, and trailing edge. Their
shadows can usually be seen through the fabric. Allowance
must, of course, be made for wash-in and wash-out; otherwise,
the parts I have specified should be parallel with each other.
Now line up the centre part of the main-plane with the
tail-plane. The latter should be horizontal.
Next, sight each interplane front strut with its rear
strut. They should be parallel.
Then, standing on one side of the aeroplane, sight all
the front struts. The one nearest to you should cover all
the others. This applies to the rear struts also.
Look for distortion of leading edges, main and rear spars,
trailing edges, tail-plane and controlling surfaces.
This sort of thing, if practiced constantly, will not only
develop an expert eye for diagnosis of faults, but will also
greatly assist in impressing upon the memory the characteristics
and possible troubles of the various types of aeroplanes.
MISHANDLING OF THE GROUND.--This is the cause of a
lot of unnecessary damage. The golden rule to observe is:
PRODUCE NO BENDING STRESSES.
Nearly all the wood in an aeroplane is designed to take
merely the stress of direct compression, and it cannot be bent
safely. Therefore, in packing an aeroplane up from the
ground, or in pulling or pushing it about, be careful to stress
it in such a way as to produce, as far as possible, only direct
compression stresses.
Pages:
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154