Measurement of Visibility From the Pilot's Cockpit on Different Airplane Types Page: 10 of 24
This report is part of the collection entitled: National Advisory Committee for Aeronautics Collection and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
N.A.C.A.. Tbcna:ical emoran:dum. 'o.-. 646
hardly possible. Lastly, itt: should be possible to doter-
mine the visibility of different airplano types from the
charts. Since only the ratio of the unobstructed to the
--obstructed portions -of the surfado of the sphore enter in-
to the question of the visibility, a true plane chart of
the surface area of the sphere must be required.
A chart with roctanuglar :coordinates (fig. 7) was
tried as the simplest kind. This i-s called a-"square
chart" in the case of land maps. An exact plotting of the
points thereon is possible, because the divisions are
o-qual i '.every direction n and intermodi Sto values may be
easily estimated or measured. This representation yields
a fairly accurate development of the surface of the sphere
in the region of the horizon, while toward the top and
boottoa.=thro- is an over-increasing .distortion. This moth-
od is' ti:orefro: very imperfect.
In Figure 8 an attempt was made in order to increase
the cloarness of the chatt, to emphasize the portions ly-
ing in the main direction- of vision by- making the degree
divisions according to a sino function.. This chart also
yields no clear representation of the field of vision and
therefore& hzs no groat advantage ov.or the fir st.-
The method of representation shown in Figure 9 ful-
fills the requirement of: true surface area and is there-
fore suitable for an evalUation of the field of vision.
The horizon' of the proposed hemisphoro of vision is here
developed as in the first method of representation and i
yields uniform divisions. In order to obtain* true surface
areas, :the di-stance betwea the horizontal lines must be
so chosen that the areas between them equal the corro-
sponding spherical zones. The method is likewise very
simple, but' also yields no good, representation.
Representing the surface of the sphere as a circular
area yields a more plastic picture. In Figure 10, the
true azimuthal equatorial pro'jectio', like that: generally
used in making land maps is used for the representation.
Aside from its clearness, this method -i-s' suitable for the
representaticafnfields of vision, because of the true sur-
f ace areas.
i _other very clear method of represeitaton is shown
in Figure 11. The degree network of' the sphere of vis-
ion is turned forward 900, so that the. pole lies in- the
direction of the zero ray of vision.
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Kurz, Gerhard. Measurement of Visibility From the Pilot's Cockpit on Different Airplane Types, report, November 1931; (https://digital.library.unt.edu/ark:/67531/metadc277430/m1/10/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.