Marcu 17, 1923] 
NATURE 363 

Recent Aeronautic Investigations and the Aeroplane Industry. 
By Prof. JoserpH S. Ames, The 
EW industries offer better illustrations than 
the manufacture of aeroplanes of the intimate 
relation between purely scientific investigations and 
the practical application of their results. As an 
example of this fact, attention may be directed to 
three experimental researches in progress at the 
laboratories and flying-station of the National Advisory 
Committee for Aeronautics at Langley Field, Virginia. 
These researches were begun and are being conducted 
in order to add to our knowledge of the science of 
aeronautics, but their results are of the utmost im- 
portance to the industry and also to the art of aviation. 
Other illustrations might well have been selected, but 
these are, in many respects, of “ actual” importance. 
The first research deals with the pressure distribu- 
Leading egge 
— aA 

Right-half 
of wing(with 
squore tipy 
ot /6°angle 
of ottack, 
without 
aileron. 
Plan and elevation showing contour lines: - 
ond built-up mode/. 
Fic, 1. 
tion over the wings, tail-surfaces, etc., of an aeroplane 
—an old problem, studied with marked success by the 
staffs of the British establishments at Teddington and 
Farnborough. What is novel in the present investiga- 
tion is the extension of the problem to aeroplanes 
making manceuvres, and to wings of different plan form, 
varying the angle of attack and the aileron angle. The 
method adopted is simple: numerous series of small 
openings are made in the surface to be investigated ; 
each of these is joined by a rubber tube to a capsule 
containing a metal diaphragm, to which is attached a 
tilting mirror ; a beam of light is reflected from this 
on to a photographic film which may be shifted, thus 
permitting a series of observations to be made. The 
apparatus in use records the pressures existing at sixty 
points simultaneously. All the diaphragms are, of 
course, standardised and calibrated. (In the case of 
* Substance of a lecture delivered before the Franklin Institute, Phila- 
delphia, on November 23, 1922. 
NO. 2785, VOL. 111] 
Johns Hopkins University, U.S.A. 
wind-tunnel experiments a number of liquid mano- 
meters are used.) 
Among the questions already investigated are: the 
change in pressure distribution produced by a loop, a 
roll, etc.; the effect of the shape of the wing-tip, 
square corners, elliptical, raked off, etc. ; the influence 
of the air-stream from the propeller. In all cases the 
pressures are measured quantitatively, and the results 
are shown in two ways: by making plaster or wooden 
models, like a relief map; and by drawing contour 
lines of pressure (Figs. 1 and 2). From the knowledge 
thus obtained, the aeroplane engineer can decide upon 
the best shape of wing or elevator, etc., and upon the 
relative strength required in different parts of his 
structure ; and further, if a breaking sand-load test 
10°--+| 

Leading edge 


Direction of wind 

\ 
Right-holf of 
wing(with 
positive 
rakej)ot 10° 
angle of 
ottack. 
Aileron 10° 
down 
10° 

Plan ond elevation showing contour lines 
ond built-up mode/. 
Fic. 2. 
is thought necessary, he can so distribute the load as 
to make it correspond to actual flying conditions. 
The second research was undertaken to learn the 
actual motion of an aeroplane in alighting, taking off, 
making oscillations and manceuvring, and at the same 
time to record the motions of the control surfaces and 
the forces exerted by the pilot (Fig. 3). A large number 
of instruments are required, all of which were newly 
designed with special reference to lightness and com- 
pactness, as well as to accuracy. The central instru- 
ment is a photographic film wrapped on a cylinder 
which is in rotation, for all records are made upon this 
by beams of light reflected from mirrors which form 
part of all the various instruments. When in actual 
use on an aeroplane, the pilot simply presses one button 
at the beginning of a manceuvre, and this starts every- 
thing. The instruments in use at the present time 
are as follows : 
(a) Chronometer, consisting of a constant speed 
