742 
NATIONAL RESEARCH COUNCIL 
would answer the following general requirements would be of great value 
to military aviation: 
Weight not more than 5 ounces per square yard. 
It should present reasonably great resistance to flame. 
It should be reasonably proof against action of salt water, moist air, extreme dryness, 
and quick temperature changes. 
It should not stretch in any direction. Its ability to retain original form as placed on 
the airplane is very important. 
It should have tensile strength of at least 75 pounds per inch width in any direction. 
Its tendency to tear and split because of tack holes through it, or because of bullet holes, 
should be as small as possible. 
(c) Development of light alloys for airplane construction. Pure aluminium 
or aluminium alloys. It is believed that a great deal can be done in this di- 
rection. So far no alloy has been developed, except possibly in Germany, 
which can compare with average Alaskan spruce in its 'specific tenacity.* 
(d) The structure of gusts. It is believed that this is of sufficient impor- 
tance to aviation to warrant considerable expense in its study. 
Painstaking investigation of the character of eddy formations caused 
when wind strikes trees, hollows, cHffs, etc., and the character of disturbances 
created by canyons, swamps, deserts, etc., would be of great value to aviators. 
This can be done not only by smoke and toy balloon work in the vicinity 
of obstructions such as the above, but also by photographic work in wind 
channels. 
A set of simple rules laying down just what the aviator may expect on one 
side or another of canyons, cities, trees, lakes and swamps would be very help- 
ful in aviation. 
(e) Radio-apparatus for aircraft. The subject of radio-intercommunica- 
tion between aircraft in flight, and between aircraft and the earth requires 
for its solution the highest possible efiiciency and reliabihty combined with 
minimum weight. 
A present tendency is to separate entirely the power plant from the main 
engine of an aircraft. The generator body in this case has a stream-line 
figure and a separate small air-screw is provided. Among other methods 
the oscillion is being tried as the actual source of continuous electromagnetic 
waves. 
(/) Bullet proof gasoline tanks. Development of a material with which 
to line or construct tanks to contain the gasoHne in an airplane in which a 
bullet hole will quickly close, entirely or partly at least. This would enable 
many a flier to get back to his own lines after having been fired upon. 
(g) Development of a fabric as good as, or better than, Irish linen, for the 
covering of airplanes. There has not been manufactured in this country 
a fabric suitable for use in covering airplanes. 
The fabric should answer all requirements laid down under transparent 
wing coverings and be, in addition, such as to shrink the proper amount with- 
out harm when cellulose solution is appHed. 
