STUDY Of TEMPERATURE AND MOISTURE
CONTENT IN WOOD AIRCRAFT WINGS
IN DIFFERENT CLIMATES
February 1944
This Report is One of a Series
Issued In Cooperation with the
ARMY-NAVY-CIVIL COMMITTEE
on
AIRCRAFT DESIGN CRITERIA
Under the Supervision of the
AERONAUTICAL BOARD
No. 1597
UNITED STATES I DEPARTMENT OF AGRICULTURE
---- H FOREST SERVICE
, FOREST PRODUCTS LABORATORY
Madison, Wisconsin
In Cooperation with the University of Wisconsin
STUDY OF TEITIMATURE AIM I,IOIS r..110 C01.7TENT
IN WOOD AIRCRAFT WINGS IN DIM '11' CLIMATES!
First Progress Report
for Madison, Wisconsin and
(June to October 1943)
Arizona
By
F. L. Browne, Principal Chemist
L. E. Downs, Associate Engineer
D. F. Laughnan, Associate Technologist
A. C. Schwebs, Associate Chemist
Observations at Tucson, Arizona,by
.Geraldine Peterson, Statistical
Clerk,Southwestern Forest and
Range Experiment Station
Summary
This progress report records the preparation and installation of
two right-hand wings from Anson training bombers at Madison, Wisconsin, and
two similar wings at Tucson, Arizona, and the observations of temperature
and moisture content made at the two stations up to the early part of
October 1943. The work will be continued until a full year of observations
has elapsed. Similar studies are being made by other laboratories in
several parts of the world.
During the middle of sunny days, even when the sly was clear,
temperature on and under the top skins of the wings was found to fluctuate
violently, sometimes changing as much as 30° F. within 5 minutes. Because
of the marked fluctuations in temperature, the manual procedure under
which a round of readings was taken every 60 or 90 minutes through the
middle of the day fails to reveal with certainty the maximum temperature
attained during the day. The highest temperature observed so far was
revealed at a time when a few thermocouples were read every 5 minutes.
This mimeograph is one of a series of progress reports prepared by the Forest
Products Laboratory to further the Nation's war effort. Results here reported are preliminary and may be revised as additional data become available.
Re-strr4e-t-e4 Nimeo. 1597
-1-
If the "full schedule" procedure of making a complete round of readings
every hour on the hour had been followed on the day in question the maximum
observed would have been no greater than it was on many other days during
the summer.
The highest temperature observed was 215° F. on and under the top
skin of the leading edge of the west wing (which faces south) at Tucson on
September 10 at 11:45 a.m. M.S.T. One point on the central portion of the
top skin of the east -wing (which slopes toward the south) reached 214'F, at
the same time. A temperature of 189° F. or more was observed at Tucson ton
times between July 23'and September 20. At Madison the highest temperature
observed was 179° P. on June 26 at 3:00 p.m. C.S.T. A temperature of 160° F.
or mo;e was recorded on 6 of 10 days of observation in June and. 5 of 14 days
in July and August but in September the highest temperature observed was
143° P. and in October not quite 120° F.
The number of hours in any one day during which temperature may exceed
some given level cannot be determined precisely from the data obtained so
far. It is estimated, however, that at Tucson from April 1 to September 30
there are many days when parts of the top skin remain above 160° P. for
at least 3 hours and some days when they remain .above. 160° P. for 5 hours.
At Madison, parts of thetop skin may exceed 160° F. for 3 hours on some days
during most of June and the first week in July.
Temperature immediately under the top skin was nearly as high as
that in the finish on the top skin. The main portion of the east wing and
the leading edge of the west wing, which were more directly irradiated by
the sun, became hotter than the main portion of the west wing. At peak
temperature the hottest parts of the top skin were on the average roughly
45° F. above the peak temperature of the black body and 60° P. above the
shade peak temperature at Madison and at Tucson were 55° P. above the black
body and 70° F. above the shade peak temperature. The peak temperature of
the bottom skins was roughly 25°_ to 35° F. below that of the top skins at
Tucson and 20° to 30° F. below at Madison. At the midpoint between skins
the peak temperature was lower than that at the top skin by roughly 55
percent of the spread between top and bottom skins.
The portion of the top skin above the spaces for gasoline tanks was
of metal. At Tucson the tem perature at the inner face of the metal cover
plates and at the midpoint of the air space beneath was essentially the
same as that at the corres p onding places in similar areas of the wing
covered with plywood.
The midpoint of the air space within the main spar attained approximately the same Peak temperature as that at the midpoints of bays between
ribs. The thick cap at the top of the main spar of the east wing at
Tucson reached 177° F. and in the west wing at Tucson reached 186° F.
Usually peak temperature for the day was reached shortly after
noon, standard time but, when the middle of the day was cloudy, the peak
sometimes occurred much earlier or much later in the day. In general,
aestri--e-t-941 Mimeo. 1597
peak temperature was reached first in the top skin, somewhat later at midpoints between skins, and still later at the bottom skin. The metal cover
plate reached peak temperature 23 minutes earlier, on the average, than the
nearest comparable plywood skin. The top spar cap was 15 to 20 minutes
behind the neighboring plywood skin and the bottom spar cap. was nearly
half an hour behind the top spar cap in reaching peak temperature.
At night, temperature relations were the reverse of those during
the middle of the day. On clear, still nights at Madison the top skin was
cooler by as much as 14° F. than the shade temperature, which was a trifle
warmer than the black body temperature. The bottom skin was very close
to the black body tem p erature and the midpoint between skins was between
the temperatures of the top and bottom skins. As these temperature relations suggest, dew frequently condensed on the top of the wings at Madison
to the point of draining off at the trailing edge in streams even on nights
when no dew was seen on the grass nearby. In, late October and November,
frost was often found en the top skins at Madison when the shade tem p erature was well above 32° F. and there was no frost on the grass.
Both the relatively large specimens of s p ruce and the thin specimens
of birch veneer placed in the wings showed that the high temperature attained
within the wings during the summer days reduced the moisture content of the
woodwork of the wings below that of wood freely exposed to the atmosphere
but protected from rain and sun. At Tucson the spruce specimens averaged
roughly 5.5 percent moisture content from July 23 to September 24 except for
a particularly hot and dry fortnight ending September 17 when the average
fell to roughly 3.5 percent and a minimum of 1.2 was observed. -At •adison
the average was roughly 8.5 percent from June 26 to August 21 after which
it began to increase.
The thin veneer specimens revealed marked changes in moisture content between night and day whenever the day was sunny enough to produce
high temperature within the wings. The general level of moisture content
was lower than that of wood freely exposed to the atmosphere outside the
wings; both the lowest moisture content and the highest moisture content
for the day were materially lower than the corresponding equilibriums for
wood with the extremes of relative humidity reported by the Weather Bureau.
The average daily change from highest to lowest moisture content, however,
was significantly less for wood inside the wings than for wood freely
exposed to the atmosphere. At Tucson individual veneer specimens sometimes fell to zero-moisture content in the middle of hot days; at Madison
the lowest moisture content observed was 3,1 percent.
The daily change in moisture content of veneer specimens proved
greater in some parts of the wings than in others. Specimens hung close
to the top akin changed more than specimens resting on the bottom skin.
Specimens in bays of large volume changed more than specimens in small
bays. Proximity to the root end and to the trailing edge seemed to
increase the daily change in moisture content.
Res-trri-ctea Mimeo. 1597
-3-
Introduction
The object Of the present study is to determine the extremes of
temperature and of moisture content attained in wood aircraft, particularly
in the wings, when the craft are dispersed on the ground. It is considered
likely that the highest temperatures and greatest extremes of moisture
content are experienced while aircraft are dispersed on the ground for
extended periods of time, though lowest temperatures no doubt occur while •
flying at night at high altitudes.
this progress report deals with tests made in June to October 1943
at Madison, Wisconsin, and at Tucson, Arizona, which represent two significant extremes in, climate within the United States. Data for climatic
conditions in other parts of the world are being obtained by other
laboratories, which will make their own reports. The Canadian Forest
Products Laboratories in cooperation with the Royal Canadian Air Force
is making tests at Ottawa and at a more northern station in Canada. The
British Forest Products Research Laboratory has been making observations
at-Princes Risborough, England, for some time. The Australian Forest
Products Laboratory in cooperation with the Royal Australian Air Force
plans to make similar tests at Alice Springs and at Cairns, Australia.
For the work. in the United States and in Canada, wings from Anson .
training bombers were provided by the Royal Canadian Air Porde from planes
on hand at Supply Depot go. 8 at Winnipeg. The wings were taken from
mainplanes that had been in service two years or more and wereCondemned for
further use on airplanes. They were stripped of hardware and fittings suitable for reuse but were otherwise intact. The ailerons were included but
the engine nacelles were not.
Installation at Madison was completed and observations started about
June 20 and at Tucson about July 20. The work will continue through the
seasons until a full year or slightly more has elapsed.
Description of the Anson Wings
Figure 1 is a reproduction of the photograph and description of
the Anson monoplane in Jane's "All the World's Aircraft, ff 1939 edition.
Only right-hand wings, cut from the main plane at a point, approximately
3 inches inside of rib No. 1, which is roughly the point of junction
between wing and fuselage, were used in this study.
Figure 2 is a drawing of the wings with unnecessary details omitted.
The front and rear box spars are of wood, Ribs are of birch plywood without lightening holes so that each bay represents essentially a closed air
space. Top and bottom skins are chiefly of birch plywood with exterior
finish applied directly to the plywood without fabric covering. Ailerons
have metal box sp ar and metal ribs of truss construction and are covered
Re-s-t-r-i-e-t-94.
Mimeo. 1597
-4-
with fabric. The ailerons are fastened rigidly, for the purpose of this
study, in position for level flight. The area of the top skin over the
spaces for gasoline tanks between rib Nos. 6 and 10 and from the rear spar
to the point marked by the ends of the short ribs in figure 2, has metal
cover plates instead of plywood. On the bottom skin a band along the
trailing edge between rib Nos. 2 and 10, about 2 inches wider than the
aileron, is covered with metal instead of plywood and the area between front
and rear spars from rib Nos. 1 to 3, closed by a bomb-bay door while in
service, is covered instead with a sheet of plywood.
There was no finish or other protective treatment on the inside
surfaces of the top plywood skins except immediately over large doors
such as that between rib Nos. 13 and 14, where there was a thin coating of
green paint. Inside surfaces of the bottom skins and the lower parts of
the surfaces of ribs likewise bad a thin coating of green paint. No
additional finishing of inside surfaces was done for the purpose of these
experiments.
While in service the finish on the exterior surfaces of the wings
'had been renewed at least once or twine. The last finish while in service had
been a yellow gloss enamel. For this work a camouflage finish having
approximately 10 percent infra-red reflectance was desired because such
finishes have been used on military aircraft and, under similar conditions
of exposure to sunshine, develop higher temperatures in the wings than are
attained with pain t s of higher infra-red reflectance such as yellow enamel.
Accordingly, before the wings were shipped from Winnipeg, they were
repainted with one coat of "gray pigmented primer" and two coats of
"matt pigmented oil varnish" of (Jerk earth color conforming to Ministry
'of Aircraft Production Specification D.T.D. 314. The new finish was
applied over the previous finishes. The thickness of the special finish
was at least 0.003 inch over most parts of the wing surfaces. Tests by
the photographic method, using Wratten 87 or 89A filters, on sample panels
provided for the purpose, showed that the infra-red reflectance was 10
percent of that of fresh magnesium oxide.
A few breaks in the wing surfaces from damage in transit together
with a few openings left after removal of metal fittings, such as aileron
levers, and inspection holes unprovided with doors, were covered with
fabric patches after the wings were installed at Madison or Tucson
(fig. 3). The fabric patches were then coated with olive drab camouflage
enamel conforming to Army Air Forces Specification 14109. This finish
likewise has approximately 10 percent infrared reflectance.
Preparation and Mounting of Wings
At Madison, the four wings for exposure in the United States were
equipped with copper-constantan thermocouples at the various places where
temperature was to be measured; with the necessary lead wires to the
thermocouples; with hangers for holding wood specimens for the determinations
Re-s-+-r4-G+-e-4 Mimeo.
1597
-5-
of moisture content; and with doors in the bottom skin to give access to
the p laces where specimens are inserted and withdrawn from the wings
(figs. 5 and 7). Two wings were then mounted for exposure at Madison
and the other two were shipped to Tucson and mounted there.
The method of mounting the wings on wood posts can be seen in
figures 4 and 6. The span of the wings runs accurately east and west. In
each pair the wing to the east stands with its leading edge facing north
and its top surface sloping back toward the south so that it is strongly
illuminated by the sun during the day. The wing to the west stands
with the leading edge facing south and its top surface sloping back to
the north so that the loading edge receives strong illumination but the
rest of the surfaces are less strongly illuminated and, in winter, are
partly in shadow even at noontime. The wings are mounted at a ,dihedral
angle of 2°, measured along the top of the front spar, and an angle of
incidence of 15° measured. along the chord of the bottom surf ace. The
angle of incidence measured along the chord connecting the top of the
front spar with the trailing edge is approximately 24°. The position is that
of the right-hand wing of the Anson airplane when standing on level ground
and resting on,the tail wheel.
At Madison the longitude is 89°25 1 W, latitude 43°05 t Y. The meridian
of Central standard time is 90°W. At Tucson , the longitude is 110°571W,
latitude 32°14 I K, and the meridian of Mountain standard time is 105°W.
In 1943 bota citios followed war time, one hour ahead of standard time,
but Tucson returned to standard time on January 2, 1944 whereas Madison
remained on war time. Original records for this study are kept in local
time, but in this report all times are given in Central standard time for
Madison and in Mountain standard time for Tucson. Mountain standard
time is one hour later than Central standard time. Time is reported
here by the 24 --hour clock, following military practice.
Other conditions being equal, the highest temperature should develop
in the wings when the position of the sun is most nearly perpendicular to
the top surfaces. At Madison the sun becomes normal to the top surface
of the main ; portion of the east wing approximately at noon solar time.
about May 16 and again about July 28. For the main portion of the west wing
the nearest approach of the sun to normal is 43-1/2° at the summer solstice,
June 21. At Tucson the sun becomes normal to the top of the east wing
about April 10 and again about September 2 and for the west wing its
nearest approach to normal is 32-1/2° at the summer solstice. Near the
winter solstice more than two-thirds cf the top surface of the west wing
at Madison is in shadow even at noon, but at Tucson it still receives
sunshine at 79-1/2° from the normal and only the trailing edge is in
shadow. At both stations some portion of the sharply curving leading edge
of the west wing is normally illuminated every sunny day in tho year but
no part of the leading edge of the east wing is ever normally illuminated.
At Madison a small shelter, heated_ in cold weather, was erected
north of the wings to house the electrical equipment at suitable temperatures for correct operation at all times (figs. 5,G and 6,D). All
Re-st-r-i-sts4..Mimeo. 1597 -5-
electrical wiring was brought into the shelter through conduits. The
balance for weighing wood specimens was also placed in the shelter house.
Figures 7,B and 7,D show the housed equipment. At Tucson the equipment
wad' placed in the Management Building of the Southwestern Forest and Range
Experiment Station near which the wings were erected.
Measurement of Temperature and Moisture Content
Three types of devices for measuring temperature are being used:
(1) copper-constantan thermocouples placed at many different points throughout the wings, (2) liquid-in-glass maximum or maximum-minimum thermometers
placed in a fell air spaces within the wings and in the air at a shaded
place outside the wings, and (3) at Madison only, iron-constantan thermocouples at one point within the wings and in the shade outside the wings.
The thermocouples are small enough to measure temperature within the
coating of finish on the top surfaces, at the face of a plywood skin, or
in the glue line between plywood skin and rib cap. They respond quickly
to change in temperature and follow closely any rapid fluctuations.
Liquid-in-glass thermometers are limited in usefulness by the relatively
large volume needed to accomodate their bulbs and by serious lag when temperature fluctuates rapidly. Maximum - minimum thermometers retain record
of temperature extremes until they can be read and reset. The copper7
constantan thermocouples are operated manually and therefore must be
observed periodically when an operator is in attendance. By means of a
switchboard, however, many thermocouples can be read in rotation with a
single potentiometer. The iron-constantan thermocouples are connected
to automatically recording potentiometers that chart temperature-time
curves continuously;-record is made by night, when no operatorAs on duty,
as well as by day. Only one thermocouple can be observed with one potentiometer with the equipment now available. Choice between copper and iron
for the thermocouples was made according to the requirements of the
potentiometers available for the study. The recording devices were not
installed at Madison until the latter part of August.
Day-,:by-day records of the weather at Madison and Tucson are being
kept by obtaining the official reports, Form 1030, of the Weather Bureau rl
stations maintained at the two cities.
Changes in, moisture content of wood within the wings are being
followed by measuring the changes in weight of wood specimens placed
within the wings. There are two types of specimens. One type consists
of 1/48-inch veneer of the sapwood of yellow birch (Betula lutes), which
is thin enough to follow rapid changes in moisture content that often
of heartwood
occur within a single day. The other type consists of pieces
of Sitka spruce (il icea sitChensis)• 1-1/2 by 1-1/2 by 11 inches it si*e,
which respond slowly to changes in conditions and therefore reveal changes
in average moisture content between the weekly weighings.
Res-t-p-i-eteed Mimeo. 1597
All of the veneer specimens, including reserves for possible replabements, needed for the two stations in the United States and for the
stations in Canada and. Australia were cut at Madison from a single birch
log. Similarly all spruce specimens for the United States and Canada
wore cut at Madison from adjacent parts of a single log, and had been
air seasoned for several years. Aal specimens of both types were brought
to constant weight in 65 percent relative humidity at 80° F., the moisture
content determined by oven-drying suitable cuttings and the theoretical
oven-dry weight calculated after weighing each specimen. At the end of
the work each specimen will be oven-dried and weighed to check the
calculations.
,Since the veneer specimens change appreciably in moisture content
during the short time required to take them out of the wings and weigh
them, snugly fitting envelopes of aluminum foil on paper were made to
enclose each specimen while it was out of the wings for weighing. The
envelopes succeed in preventing appreciable change in moisture content
for several hours. The tare weight of each envelope is observed at least
once on each day in which it is used. Figure 7, E shows veneer specimens,
their envelopes, and spruce specimens.
Veneer specimens are used in sets of three. A set was placed in
each location within the wings at which observations are made. If, for
example, observations are desired at 8, 11, 14, and 17 o'clock on a given
day, No. 1 specimen of a set is removed at 8 Oclock, weighed in its
tared envelope, and returned to its place in the wing as soon as practicable.
At 11 o'clock No.2 specimen of the set is similarly removed, weighed, and
returned, at 14 o'clock No. 3 s pecimen, and at 17 o'clock No. 1 specimen,
Thus a specimen has always been undisturbed in its place in the wing for more
than 6 hours before it is removed for weighing. Specimens reach substantial equilibrium within that time even after large change in moisture
content.
Spruce specimens axe used in sets of four, One specimen of the set
is weighed each week, choosing specimens from the set in rotation so that
any one specimen is weighed only once in four weeks.
S
119
bo l s
0
I I nt i 1e
on a d Doc tie
I. servations
As indicated in figure 2, each location of observations within the
wings, in which thermocouples, thermometers, or wood specimens was placed,
is identified by a reference number. The east wing at each station is
designated by letter 16 and the west wing by letter W. Thus, for :example,
the bay inthe oast wing at Madison bounded by ribs Nos. 3 and 4, the
front and rear spars, and, the top and bottom skins is known as location
"Madison E2.° Outside of the wings there are the "shade location," which
is the place on the wood cross brace supporting the root end of the east
wing, shown in figure 7C, where thermometer and thermocouples are placed
to read the temperature of the air surrounding the wings, and the "black body
location," The "black body" is a 3/4-inch brass sphere with a thermocouple
ustri-Tbs-d-Mimeo, 1597
at its center, painted with lusterless black paint, and mounted on top of
one of the long posts supporting the root ends of the wing as shown in
figures 4 F, 5 G, and 67;
Thermocouples are designated by letter T with subscript numbers
to indicate their position within the location of observations. Thermocouples T o are buried in the exterior paint on the top skin, T 1 are held
tightly against the inside surface of the top plywood skim T2 are suspended in the air space midway between top and bottom skins and usually
midway between ribs or other boundaries of the location, Ts are held against
the inside surface of the bottom skin, and T4 are in the glue line between
the top skin and a small block of spruce representative of a rib Cap.
Thus, for example, the symbol "Madison E2T 2 " indicates the thermocouple in
the middle of the air space in location 2 of the east wing at Madison.
Veneer specimens are designated by letter V with subscript numbers
to identify the individual specimens in the sets of three. Veneer specimens hung near the top of a location of observations have the subscripts 1,
2, 3, those resting on the bottom of a location have the subscripts 4, 5,
6. Thus "Madison W3V2 " indicates the second one of the set of three
veneer specimens placed near the top of location 3 in the west wing at
Madison.
Spruce specimens are designated by letter S with subscript numbers
1 to 4 to identify the individual Specimens in the set of four.
:able 4 lists the thermocouples, thermometers, and wood specimens
placed in the various locations of observations, together with their symbols,
and gives the boundaries of the locations and the depth from top to bottom_
skins for some of them. Table 4 is useful for interpreting the symbols used in some of the figures and in other tables.
Schedule of. Observations,
Spruce specimens are being weighed to determine their moisture
content on a schedule that does not vary during the entire period of study
of the wings. The relatively largo spruce specimens reveal chiefly the
seasonal changes in average moisture content and therefore they need not
be weighed frequently. One specimen from each set of four in a location
is weighed each week. At Madison the weighings are made on Saturdays and
at Tucson on Fridays.
At Madison only, the shade temperature and the temperature at W1T1
have been recorded continuously since the recording potentiometers were
installed and adjusted about the end of August.
Other readings of temperature and weighings of veneer specimens are
made in accordance with one of three schedules of observations known respectively as the stand-by schedule, the reduced schedule, and the full
Ree-t-r-i-ete-d Mimeo. 1597
-9-
schedule. Extra observations are made from time to time as may be suggested by the needs of the work or developments in the weather.
The stand-by schedule involves a minimum of labor. It is in effect
whenever tho other schedules are not in operation. Under the stand-by
schedule no readings of temperature are made but veneer specimens EIV 1 , W1V1,
E3V4 , W3V4 , E5 V4 , and W5il are weighed daily, except Sundays and
holidays, at 8:00 o'clock local time. If sudden changes or serious departure from expected trends appear in the moisture content of specimens
weighed under stand-by schedule one of the other schedules is resumed
to provide more complete data. Whenever the stand-by schedule has continued
without interruption for 14 days one of the other schedules is resumed for
at least 3 days at Madison or at least 2 days at Tucson. Also whenever
there is weather of a kind for which data have not yet been obtained, one
of the other schedules is resumed.
In summer the alternative to the stand-by schedule is the full
schedule and in winter it is the reduced schedule. Under the full schedule
in 1943 a full round of temperature readings was made at least five times
a day, Sundays-and holidays included, typically at 7:00, 11:00, 12:00,
13:00, and 16:00 o'clock, although at Madison additional rounds were
usually made. In 1944 it is planned to make at least eight rounds of
readings a day at Madison, Veneer specimens from all locations of observations are weighed at Madison four times (7:00, 10:00., 13:00, and 16:00
o'clock) and at Tucson three, times (7:80, 12:30, and 14:00 o'clock)
daily. Under the reduced schedule, temperatures are read at Tucson at
least three times, say 8:00, 12:00, and 15:00 o'clock, and at Madison
usually six times (8:30, 10:30, 12:00, 13:00, 14:00, and 15:30); veneer
specimens are weighed twice daily (7:00 and 13:00 at Tucson, 8:00 and
14:00 at Madison).
In general, the full schedule is in operation continuously for
about 2 weeks centering on the June solstice, for about 2 weeks at the
time of the spring and fall equinoxes, and for a few days at suitable
intervals between, The reduced schedule is in operation for about 2
weeks centering on the December solstice and for a few days at suitable
intervals between the fall and spring equinoxes. In 1943 the full
schedule was followed for the first two weeks after the wings were
installed.
Extra observations of temperature were made at various times at
both Madison and Tucson, particularly during the summer season. S o me of
them were for the purpose of studying conditions before and after sunrise
and sunset or the course of temperatures during the night. Others were
for the purpose of studying the rapid fluctuations in temperature within
the wings during the middle of suony days in 01/4MOr. Qn 0 1101 Q11%mq
days, a small number of thermocouples at places that tend to attain
highest temperatures were read atintervals of 5 or 10 minlit e4 'or
2 or 3 hours in the middle of the day.
R&st-ri-eterd Mimeo. 1597 -10-
Results
The data obtained so far are p resented chiefly by means of graphs
and tables that do not require extended discussion.
Temperature
Figure 8 shows typical records of the course of temperature at
thermocouple W1T 1 during late August and early September when the technique
of continuous recording Wag being developed. In charts A and B of figure 8
the curve for WiT 1 (full line) p resents an imperfect record that exhibits
serious lag behind the periodic manual data (open circles) for the same
location at 8:30, 10:30, 12:00, and 13:00 o'clock. The lag was attributed
to the large size of the iron-co-nstantan thermocouple, made of No. 14 gage
wires, in use at that time. When means were found of making the thermocouple of Bro._30 gage wire, the curves obtained, such as figure 8D,
agreed satisfactorily with the intermittently observed copper-constantan
'thermocouple and revealed fully the rapid fluctuations in temperature
during the middle of sunny days. A typical record during the night is
shown in figure 80.
At Tucson, where recording p otentiometers are not yet available,
the rapid fluctuation in temperature during the middle of clear days was
demonstrated by the laborious procedure of making many readings of a
limited number of thermocouples at short intervals of time during the het
portion of the day. Typical results appear in figure 9A, the portion
from 12:00 to 15:00 o'clock on July 23, and in figure 90. Unless readings
are made very frequently, the rapid fluctuation remains undisclosed as
for July 22.
in figure 9B and the portion of figure
a
The highest temperature so far observed, 215° F. at Tucson W1T1
at 11:45 on September 10, was revealed by making readings at intervals
of 5 minutes (chart C, f ig . 9). If no more than the full schedule
readings ead been made on September 10 the highest temperature found would
have been 190° F. at 12:00 and again at 13:00 o'clock, a reading that,
as indicated in figure 11, was observed several times during July, August,
and Sep tember. It seems likely, therefore, that a temperature above 200° F.
was actually reached on other days besides September 10. Similarly,
figure 8D for Madison indicates that the periodic readings according to
full schedule may fail to reveal the maximum for the day by as much as
20° F. If the recording potentiometers had been in operation during June
and July it seems probable that the highest temperature observed, 179° F.
at 13:00 o'clock on June 26, would have been materially exceeded.
Near noon on clear or reasonably clear days during the summer,
the top skin on those parts of the wings illuminated by the sun most
nearly normally were above the tem p erature of the air in the shade under
the wings by approximately 60° F. at Madison and 7CP F. at Tucson.
Restricted Mimeo. 1597
-11-
The top skins were above the temperature of the black body exposed directly
to sunshine over the wings by approximately 45° F. at Madison and 55° F.
at Tucson. By sunset or slightly before, the temperature of top skins,
black body, and shade usually drew together at a level somewhat below
.
the shade temperature at noon. On clear nights the order of temperatures reversed; the black body was slightly cooler than the shade temperature (even
when the shade thermocouple was moved to a position above the wings near
the black body) and the top skins of the wings were as much as 14° F.
cooler than the shade temperature. Toward sunrise the temperatures again
drew together but the daytime order was not regained, as a rule, until
well after sunrise,
`the greatest excess of skin temperature above shade or black body
temperaeure was observed on cloudless days with little or no wind. Strong
wind tended to cool the top skins; clouds between sun and wings cooled the
top skins greatly. With heavily overcast sky the top skins sometimes
were held within less than 10° F. of the shade temperature and during rain
there was often no measurable difference in temperature.
Reasonable interpretation of. figures 8 and 9 together with the rest
of the data suggests that, at Tucson, from April 1 to September 30 there
are many days when -,)arts of the top skin remain above 160° F. for at
least 3 hours and some days when it remains above 160° F, for 5 hours.
At Madison parts of the top skin may exceed 160° F. for 3 hours on some
days during most of June and the first week in July.
The upper halves of the bar charts of figures 10 and 11 show the
highest temperatures observed at each of 5 locations within the wings together
with the highest shade and black body temperatures observed on each day of
full schedule ..from June 20 to September 25 at Madison and from July 18 to
September 28 at Tucson. Weather data given below the bars account reasonably well for the differences from day to day. Com p arison of figure 10
with figure 11 shows the greater length of-the season of high temperature
at Tucson than at. Madison.
The distribution of high temperatures at all the places in the
at which there were thermocouples is indicated by the data of
1, which reports the highest temperature observed (excluding Sep-10 at Tucson because a few thermocouples only were read on that
the average of the highest temperature each day during the
SUMMIT, and the average time of day at which the p eak temperature was
observed at each thermocouple.
wings
table
Umber
day),
In general, the top skin of the east wing and the top of the leading
edge of the west wing were the hottest parts. The top skin of the west
wing, because of the slope toward the north, was appreciably cooler.
The inner face of the top plywood was no more than a few degrees cooler,
as a rule, than the, coating of exterior paint immediately above it. The
air within the wings at the midpoint between skins was 15° to 20° F.
cooler at peak temperature than the top plywood in the east wing and
correspondingly 10° to 15° P. cooler in the west wing. The inside surface
Reil-tr-icted Mimeo, 1597
of the bottom skin was 10° to 15° Y. cooler than the midpoint of the air
space. The top skin reached its peak temperature on the average a little
after noon, though on any one day the time varied greatly according to
the timing of the passage of clouds over the sun. At Tucson theYtime of
peak temperatures was a little later in the day than at Madison as would
be expected from the positions of the cities in their time zones. At the
midpoints of the air s p aces, the time at which peak temperatures were
reached lagged somewhat behind that for the top skin. The bottom skin
reached p eak temperature still later in the day. Last points to reach
peak temperature were the spars, particularly the bottom spar caps.
Under the metal cover plates over the spaces for the gasoline tanks,
the peak temperatures wore no higher than they were for comparable locations under p lywood top skin but under metal the peak temperatures
wore reached earlier in the day than they were under plywood.
Moisture Content of Spruce Specimens
rigUre 12 indicates the week,eby-week changes in moisture content of
the spruce specimens kept within the wings. At Madison the moisture content was fairly steady at approximately 8.5 percent from June 26 to
August 21 after which the moisture content began to increase. At Tucson
the moisture content held at approximately 5.5 percent from July 23 to
September 24 except for the 2 weeks ending September 17, when it fell below
3.5 percent. The lowest moisture content of a spruce specimen observed
at Tucson was 1.2 percent.
On July 19 samples of woodwork were obtained from wreckage of air'planes at a training field about 30 miles from Tucson. The wreckage had
been kept out of doors but the . parts had been so badly broken that there
had been none of the heating effect from enclosed air spaces. The material
was therefore considered representative of aircraft woodwork in equilibrium with the atmospheric conditions of the Tucson region. The moisture
content of the samples was 5.2 to 6.9 percent and averaged 5.9 percent.
figure 12 indicates significant differences in moisture content in
different parts of the wings. Table 2 presents the comparisons more
conveniently by reporting the average moisture content at each location
of observations for the periods June 26 to August 21, and August 28 to
October 9, at Madison; and July 23 to September 21, September 10 to 17,
and October 15 to November 5, at Tucson. In general, moisture content was
lower in the oast wing than in the corresponding parts of the west wing.
In the leading edge of the east wing the moisture. content was usually
higher than it was in the rest of the wing, corresponding to the less
intense illumination of the leading edge by the sun. In the west' wing
the leading edge is the part most intensely illuminated and was therefore
expected to exhibit the lowest moisture content. At Tucson the leading,
edge of the west wing did develop lowest moisture content but at Madison
such was not the case although the loading edge of the west wing was drier
than the leading edge of the Oast wing. The reason for the discrepancy
at,Madison is not now evident.
-
Ret.14.e.‘e_e,
Mimeo. 1597 -13-
Moisture Content of Veneer Specimens
The lower halves of figures 10 and 11 show the changes in moisture
content during the day for the veneer specimens at locations El, E3,'E5,
Wl, and W3 hung near the top skin, for each day on which observations
were made within the period of this report. The black bars in figures
10 and 11 represent the daily changes in moisture content that would be
experienced by wood specimens thin enough to remain always in equilibrium
with their environment and kept freely exposed to the atmosphere but
sheltered from sunshine and rain.
The daily changes in moisture content of the veneer specimens in
the wings are clearly related to the development of high temperature
within the wings by the absorption of sunshine at the top skin. On
sunny days the veneer specimens lost moisture during the middle of the
day and regained moisture at night, the extent of the movement depending
largely upon the extent of heating of the wings during the day. Sometimes, on heavily overcast days with rain or high humidity, the specimens
in the wings became more moist in the course of the day,„ The general
effect, however, was to keep the , veneer s p ecimens within the wings at
lower moisture content than that of wood freely exposed outside the
wings, at least during the summer and early fall seasons. At Tucson,
the osisture content of some veneer specimens occasionally fell to zero
during the middle of particularly hot, dry days; at Madison the lowest
moisture content observed was 3.1 percent.
Table 3 presents the data for more detailed study of the changes
in moisture conditions that occurred daily in different parts of the
wings. Average values for the highest moisture content, lowest moisture
content, and change in moisture content during each day of observations
within certain intervals of time are reported for each set of veneer
specimens at Madison and at Tucson.
The magnitude of the average daily change in moisture content of
veneer specimens within the wings was always less than that for wood in
equilibrium with the air outside the wings. If it is assumed that, about
sunrise, the relative humidity as well as the temperature of the air
within the, wings was about the same as the relative humidity and temperature of the air outside the wings, the lowest moisture content to which
the veneer specimens fell during the day was not so low as that calculated from the extent to which the temperature inside the wings increased
during the day. It therefore appears that the air within the wings
takes up enough moisture from the woodwork enclosing it to partly
counteract the extreme dryness that would otherwise develop at the peak
temperatures.
The veneer specimens placed over the large vent hole in the bottom
skin near the trailing edge in location 5 frequently attained higher
moisture content than any other specimens, After rain storms these
specimens were sometimes found wet beyond the filer-saturation point.
Restrictmd Mimeo. 1597
-14-
Veneer specimens hung near the top skin generally changed more and
averaged lower in moisture content than specimens placed on the bottom
skin at the same locations. Specimens in large bays such as locations
2, 3, and 5, generally exhibited greater range in moisture content with
smaller lowest and greater highest moisture content than specimens
similarly placed in small bays, such as locations 1, 4, and 6. The magnitude of the daily change in moisture content apparently was greater
toward the trailing edge, such as location 5, and less toward the leading
edge, such ac location 1.
Interp retation of Conditions Within the Wings
The results suggest that two factors tend strongly to reduce the
daily changes in moisture content that occur within the wings below the
variations calculated from the large changes in temperature. First,
the ventilation of the airspace within the wings through the vent holes
in the bottom skin is feeble when the airplane is parked on the ground.
mho air within the wings, therefore, can be considered essentially
stagnant, Both the absolute and the relative humidities of the air
within the wings may differ materially from those of the air outside.
Second, as the temperature of the air within the wings rises during the
day the absolute humidity is raised by moisture taken from the surrounding
wood, a factor that is more pronounced in small bays than in large ones.
In other words, rise in temperature during the day shifts moisture from
wood to enclosed air and drop in temperature at night shifts moisture
back from enclosed air to wood. During the day, however, there is also
loss of moisture from the plywood skins, particularly the top skins,
to the outside air which apparently exceeds the regain of moisture from
outside air during the night. That is not surprising because the difference
in temperature between wings and surrounding air is small at night and
large during sunny days. The wings therefore oscillate about a mean
moisture level that is considerably lower than that of the surrounding
atmosphere, Significant modification of these results is to be expected
under winter conditions, particularly at Madison, when temperatures are
lower, days are shorter, the illumination of the wing surfaces is more
oblique, and the proportion of cloudy days is greater.
If it were possible to provide abundant circulation of outside
air through the wings while the airplane was grounded under summer conditions the temperature attained within the wings during sunny days Would
be much lower and the woodwork would not be dried to such low moisture
content but the daily change in moisture content would be increased.
Presumably airplanes in flight experience the modifying effects of
improved ventilation of enclosed air spaces.
In airplanes with ribs of truss construction instead of the plywood webs used in the Anson wings, it is possible that distribution of
temperature and of moisture content differ somewhat.
Ree-t-rIcta4 Mimeo. 15 97 -15-
A protective finish of high moisture-excluding effectiveness on
all interior surfaces presumably would tend to reduce the extent of the
daily changes in moisture content but, by reducing the movement of
moisture from wood to enclosed air during the hot part of the day, it
probably would tend to increase the amount of drying to the outside air,
thereby further reducing the level of moisture content of the wings. It
may be doubted, however, whether the two coats of aircraft sealer now
Commonly specified in the United States exert any appreciable effect
en the moisture content or the daily changes in moisture content.
High moisture-excluding effectiveness of the finish on exterior
surfaces, by retarding drying to the outside air during the hot part of
the day, probably tends to hold a higher level of moisture in the wings •
during dry weather. During rainy weather it retards absorption of
moisture through exterior surfaces. During the summer season at least,
highly protective exterior finish undoubtedly. helps to keep the woodwork
at more nearly uniform moisture content.
Res-t-r-i-ctkaa. Mimeo. 1597 -16-
GREAT BRITAIN
(2&)
AVRO---contiltual.
Coastal Reconnaissance Monoplane (two 810 h.p. Armstrong Siddeley "Cheetah IX" engines).
THE AVRO "ANSON."
Fvrz.—Twin-engined coastal regonnaisssnce_monopktne.
Wusus.—Slix -gle-piece -raiiiirever monoplane wing, 'bonsisting of two
box:Nars of spruce and plywood construction with plywood and
slifuoe ribs . and plywood covering. Bakelite . plywood. which is
stronger than casein plywood and is impervious to water, .is used
throughout. The wing. is let into the fuselage structure so that
the underside of the wmg is flush with the bottom of the fuselage.
Long and narrow "Prise" type balanced ailerons are fitted.
FUSELAGE —Rectangular welded steel-tube structure, with rigid
braising. Fabric covered over wooden fairings.
Tam UNrr.—Monoplane type. FE —Tail--plane of same type of
construction as the wing, being built up of spruce frames with
plywood covering. Rudder and elevators of welded steel-tube
construction, fabric, covered. Fin, also of fabric-covered welded
steel-tube construction, is built integral with fuselage. Trimmingtabs to elevators.
(INDEBOABRIAOE.—Of retractable type consisting of two separate
units, one on either side of the fuselage mounted under each
engine nacelle. These undercarriage unite are arranged to retract
into nacelles. The shook-absorbing units are of compressed-air
type. Non-retratstable oastoring tad-wheel.
Poway PLANT.—Two Armstrong Siddeley "Cheetah" IX radial aircooled engines developing 310 h.p. at 2,100 r.p.m. at 6,000 ft.
(1,830 m.). Two entirely independent engine installations, each
engine being provided with its own fuel and oil tanks. These
are of welded aluminium construction and are mounted in cradles
in the wing. Petrol feed by means of duplicated fuel-plumps
mounted on the engines. . The engines are mounted on welded
tubular-steel frames built out from the wing and bolted directly
to the front spar.
Accosuaonartox.—The pilot's seat is in the extreme nose of the
Fuselage on the left tide. Solo tontrola only are provided but
removable dual control can he fitted if desired. The pilot is
provided with a fixed Vickers gun mounted on the left side of the
fuselage. Immediately behind the pilot, also on the left side is
the navigator/bomb-saner a seat. A table 1B provided, also a
panel for navigational instruments. An alternative seat. For the
navigator is provided immediately to the right of the pilot. When
not in use this seat. can be folded stung the side of the fuselage.
The bomb•aimer's position is in the extreme nose of the fuselage
on the right aide. A eliding door in the floor when o pened permits
the ties of n Wimperis co/vac-setting bomb-sight. An adjustable
windscreen prevents the entry of air through the aperture. There
is provision for the necessary bombing instruments. On the
bomber's right hand are the controls for releasing the bombs.
Internal stowage is provided for 2-100 lbs. (50 kg.) and up to
8-20 lbs. (10 kg.) bombs in the wing. The pilot is also provided
with bomb-release controls. The wireless-operator/gunner's seat
is on the left side of the fuselage immediately behind the navigators.
The wireless apparatus is mounted in front of the operator and a
table is provided. A fixed aerial is provided hut there is ohm provision for a trailing aerial. At the after end of the cabin is a small
door which communicate* with the rear gun-station which is
equipped with an Armstrong Whitworth totally-enclosed rotating
gun-turret. One Lewis gun is used and stowage is provided for
five ammunition drams. Entrance to the cabin and all the crew's
stations is through a door OD the right aide of the fuselage.
DIstENstome.--Span 66 Ft. 6 in. (17.26 m.), Height 13 ft. 1 in. (4 tn.),
Length 42 ft. 3 in. (12.00 m.), Wing area 410 sq. ft. (38.1 sq, tn.).
Wr.lowre AND La...nit:Ga.—Weight empty 4,950 lbs. (2.248 kg.),
Military load, crew. fuel and oil. 2.71i Poe. (1,230 kg.). Weight
loaded 7,863 lbs. (3,476 kg.). Maximum permissible loaded weight
8.000 lbs. (3,627 kg.), Wing loading 19.5 lbs./lig, ft. (95.2 kg,,lsq.
m.). Power loading 12,91 lbri./11.1,_ (5_135 kg./h.p.).
Piraronisswca.—Brfaximum speed at, sea level 170 m.p.h. (272 km./.1.),
Maximum speed at 7,000 ft. (2,130 in.) 188 m.p.h. (303 km.h.),
Maximum speed at 10,000 ft. (3,050 tn.) 186 m.p.h. (297.0 km.h.),
Maximum speed at 15,000 ft. (4.580 isi.) 175 m.p.h. (280 km.h.).
Landing speed 62 m.p.h. (NG Craising speed at 6,000 ft.
+1.83G in.) 158 m.p.h. (252.6 km.h.). Initial rate of climl, 750 ft.trnin.
(229 in./min.). Rate of climb at 0.000 ft. (1.830 in.) 905 ft.imin:
(276 mor min.), Climb to 5,000 ft.. (1,530 m.) 5.2 mina., Climb to
10,000 ft. (3,050 m.) 11.6 mine., Climb to 15.000 ft. (4,680 rn.)
2L7 mina, Service ceiling 19,500 ft. (5,948
(NCrrN.—if required, flops con be fitted to the "Amami," bus they
hate not bun taken into amount in the weight dean given above. When
Saps lira fitted the tetinging speed is 57 m.p.h. = 92 km.h.)
Z M 49081 2'
Figure 1.--Desoription of the Anson monoplane in Jane's "All the World's Aircraft,"
1939 edition.
4
as
Figure 3.--Use of fabric patches to repair
defects.
A,
Cradles holding leading edge on flat car
just before shipment from Madison.
B,
Crushing of leading edge where it rested
on cradle after reaching Tucson.
C,
Damage done to leading edge.
D,
Repair of damage by fabric patch before
applying camouflage enamel over the
patch.
E,
Fabric patch painted with camouflage enamel
covering inspection at trammel point,
through which a cable was passed to
anchor the wing tip o the supporting
posts.
F,
Use of fabric patch to close openings
in the bottom skin not needed for access
to the interior.
iientr+etred ilimeo. 1597
Zit 49588 F
Figure 4.--Some details at Nadison.
A, Arrival of the 4 wings from Winnipeg.
3, Method of handling wings at Madison.
C, Hethod of installing therr:locouples and
wiring through inspection holes.
D, Mounting of wings at Madison, showing
wings and shelter house north of
wings.
Details of fastening at w i ne tip.
Petails of fastening at-root end, also
Jhowing black body on top of post at
left.
Rostriotod Mimeo. 1597
Zit 49592 F
Figure 5.--Details of wiring for thermocouples
A,
Location 4 near wing tip, thermocouple held
at midpoint of air space by string stretched
between stringers, wires stapled to stringer,
and tag to identify the thermocouple wires.
B,
Location 2 near root end, thermocouple held
under top skin by tape, another held by
string at midpoint of air space, wires
strung through holes in stringer, tags to
identify thermocouple wires.
C,
Location 3 , near center of wing, wires from
thermocouple embedded in exterior finish on
top skin, thermocouple held under top skin
tape, thermocouple held by string at
1/14-,:int, and veneer ;specimens hung from
Atr*ngt) r under top, skin.
D,
Main cable of wires passed through holes in
ribs for aileron cables, also showing tape
over soldered joint Where. constantan lead from
a thermocouple joins main constantan lead
wire.
E,
Plywood covers made to close inspection holes.
F,
Mode of access to interior through inspection
holes.
G,
Conduits carrying wires from root ends of
wings to' shelter house, also black body on
top of post at root end of east wing.
Itt)btitart'd Mimeo. 1597
I
z In 9 Y 3-
iYF
Figure 6.--.Details at Tucson.
A,
Transfer of wing from flat car to truck.
B,
Road up the hill to Experiment Station,
showing typical desert vegetation and
topography of the region.
C,
Holes dug for setting posts and strings
for aligning them.
D,
Posts erected, waiting for concrete
footings to set, while wings temporarily rest on the ground,
E,
Wings erected south of Management
Building.
F,
Mounting at root end, conduits carrying
wires from root ends to Managelient
Building, and black body on top of
post at left.
Re-strict-ea Mimeo. 1597
•
ZM 49591 F
Figure 7.--Details of electrical instruments and
moisture specimens.
A, Temporary arrangement at Madison before
shelter house 'was completed, showing
potentiometer, dry cell, switchboard,
and two cold junctions standing behind
potentiometer.
13, Arrangement of potentiometer, galvanometer,
and switchboards in shelter house at
Madison.
0, Maximum -minimum thermometer, shade thermocouple for manual operation (fine wires)
knife switch for, shifting to a shade
thermocouple near the black body for
readings at night, and shade thermo:ouple for automatically recording
potentiometer (heavily insulated wire)
under root end of east wing at Madison.
D, Two recording potentiometers and analytical
balance_in shelter house at Madison.
, SprUce specimens, a veneer specimen, veneer
specimen , in foil envelope, a veneer
Specimen partly inserted in an envelope,
and,: . tweezers for inserting and withdrawing
specimens from envelopes.
F, Veneer specimens hanging under top skin and
spruce specimen hanging under stringer
in location 3.
Reittri-c-t-eA Mimeo. 1597
E
ZM 49590 F
II
Figure 8.--Typical temperature data obtained at
Madison with continuously recording
Potentiometers compared with intermittent manual equipment.
A & 3, Data obtained with a thermocouple made of
heavy wire at location WiT 1 showing only
gentle undulations in the curve and serious
disagreement with manual data for a thermocouple made with fine wire located at the
same place.
C,
Typical record made at night.
D,
Data, obtained with a thermocouple made of
flne wire, showing abrupt oscillations
in the curve and good agreement with
manual data.
-Rers#ri-etred Mimeo. 1597
(E
Hour 3o1 Da
0
U.:
(C.S.T.) on
August . 24, 19433
•
MIMM n11n 1=1nnn !
INIIIIIIMI=
iln
MINIMEn •nn111•nn111n 11n11n11n
1;1
n111•1n1nMMIEMBIEMWIrirrni
. MIIMnnn
n=11• n1111%711rilii nnZnn•..s
wAre..1111Mn
lnINI=n11111MPAINc
n
mial.
nrinmonezeinemn mar
.1n
-•%..e.mo
M11•11PIUMMIIIIMIIIIINIEME
TIZZIVZIEEZZEIMIGESCCEEEIMPft Vi-ENEN __
ai;:1
IM n1111n•nnn
1nIn
1...1.1111
n111n •
T
2
n111M
6 12
1
i
1
EMMINIPW*2=1111.11•11=nn
11En11n1nniilli
- 1•11=1nn
••n••••n11n111n=111E.....
E0
.
NITh
MAIM
0
ni . WIN"
P
MAZY
g
Hour ofDa
1
nglraillidlirzirimpullnsmamr_
(C.&T)
3LK/IT WIRD
on
August
SL
Sti.LWEA
SMO
R
S! itL'D
-
IMMIIMEIM
60
40
•
160
140
120
n•n11
nnn
MINIIInn1111,:si.W2IMIllraMilkinnnnn
110n1nn 11117FiliEMINIIIITAInhiNIMnn•=111111
nMMINMerAILIPTAn1nn•111n 1n..
nIN
In11
-41111n
1==1.111MAIIMIPIIMIMIIIIM=
Pn1111MIP PIARIaMf..iiiiiiiMIEF-JuiMP I InnnIIIMIE
1n11nMill
,N4,0
KAMP
Da
hour of
ma
L.
80
iln
4444
MOM
40 MIMIIIIMII.1
©
100
C EAR
110 MIND
IMMIIIIIIIIIIIIMailliMIIIIMINIMM nINIMMIIMM11nn
••11.111mmall
1 poi•Mn
ThrilliMMENIn111
IMIIIIIIIIMnIMMIMIIMIMMOIMIhiaiiiii
1.-h'
120
il1711.1111MINE n11M1111WIIMIn:nn
r
44
ND
z•tox l aWr
1943
25,
' n111•• nnnn•n111
a it0
I50
160
140
-U
h, ,
il
cc ea
,=•.[ 60
a
,1
Q.
40
E
,,
A
kff
on September10 11, 194 3
a
muinnnn•••n•n
nnn1111nNIMINTINilrr
–IPIMOINI n11nnn
n111nn111WWAM171 ..AIMPAIMMIIIMIIM=IMMIIIMIn t_
inniimer,rriiimaam.n=2711.%nnnn x
Mr
..iiilinlIn1 n1nn•==n=11M11111= m
1nn!SILIM111nnnn=121
r lt1.1nnIl
. •Mi
60
40
140
120
100
ea
1n=1111n111n111Mliiinnn••171n11n
iir.dmwmnnmirimmiwinNt-inmotilin
80
MP
AIIIMMINIMMI
40
!roinWWINIMINnnnnnnnn•1n1111M
T
MAZY
NO
SL. W
KEY
50
(CST)
1.1.11.11r
ILa 20
WEATHER
M 49726 7
nNIMINNIMIIIIIIIIIIIIIMEMINI nINIMMIIIIMININIn
1111Mall=1n11n111
nINIMIIIn1 nIn
RE
IN
re till
IL ' I 1 tEW I I" 41A14
NrY7M0
WINO
'ill•fl"
100
11nnnn =1MIMINIIIIIIMIlirmi
,
HAZY
31.. WINO
f
HAZY
5L. WIND
t
UDY
STR
CLOON0 WIND
CONTINUOUS RECORD OF THERMOCOUPLE AT W 1 11 "'As's
IN SHADE ----PER IODIC READINGS OF THERMOCOUPLE AT MITI
IN BLACK BOOM
, IN SHADE •
PERIODIC READINGS OF THERMOMETER IN SHADE X
20
Figure 9.--Typical temperature data obtained at
Tucson on a few days when readings
were made at short intervals of
time through the hot part of the
day.
A, July 22 and 23 and the night between--note
the effect of cloudy weather during the
latter part of the night and the morning
of July 23.
13, July 27.
C, September 10, when the highest temperatures
were observed.
4e traded Mimeo. 1597
n
€®1.
11F"-----111111
-
-4
11
.11
51
^ 11111:1111
mil
,,,'
-i,
.
.-
.
:.,,,44
il
1 Iraq'
.
I
1118
,
NI
ncl
g
III
I1
1
poi
lid 1
4
;:-
1
/
14
n
g3 ulna
n
g
.
.4.
%
0nn
.4
1
_ -AA
1- 7:
§
w-i n
.
MPbME
Illimbhl i
r,da
.4ca, ''
*
-ii
9
.
..._e,
n
-i.
--)
.4
1111
.•
A
t 312
.-A
ZA
El
mu . §:i
gmi
1
vi
°r
72
Iliqm 1
114.1J
1111.6111k1
t.g
I.3
0 .0
Z.
I
ITIMI.6
i
n
4-gD1,.
AVMS
..
,t
'3einivnew31
ID0 ga
17
00
.4
rrl
cr—.
z .
n
!
a
.-=
®'
n
Iri
al
.q
-4
A
AS
c
es
11111m11itI*I 1:
A
1
0,t,., 11111111 A's
4 g 1111E,
JiSlt
111 RI
11 lit
10211118 1
10
IBA IV
10
nnutzi '2unlvti/cii,421
1 1
IN
"III
III
11
- 1111 I 111
z:
g
;
.
n
a
.
1g
11
§
R
g
§
i;t33d3C1 ' 2tIn.LWU3d1431
Ct4.1
=
=1
w.,
X
Figure 10.--Maximum temperatures observed at Madison
at five locations in the wings, at the
black body, and in the shade, together
with the change in moisture content of
vonee+ specimens at the same five locations and the change in moisture content
of wood in equilibrium with the relative
humidity reported by the Weather Bureau
for each day on which observations were
made between June 20 and September 25,
1943.
--Restrl-e-t-eil Mimeo. 1597
3 3
0
.....
8
171717/
II
00
/
Ili
,Rim• 000.
y.,
"/,?+0.0
L'Amm=r-
fT
.00.?
I
wh
rs
P1 0
n1 V* .0
0.10n01.1110SUGMINME=0
In
17501=C
In00n101.111ialikinkiporma
1100
.1,0141
SI
=CIE
rn
I!
•
IsmarREErhiprzmam
et Cl ••nn
"
• 1204,
• 1:110111
Rr
9ilessa
ramilimps
co,Bh
404
,ina.ere"`""
00
O
aov
" 47":""
ox
.0 . 0 0
0000t00•n,0.
"2.
cfP
000 0./
6 .0.01
=)=M
001013
_..
ion, O,
• en 0.
1.0 vas
/0 000 M
11.1.1
on 0“
1an00‘ 717/1e.
1 Ohio,
".
.00012"
'2g
41-13:111:5';' "
11 ‘"`!`4.1
•n•-nLinilml_iet33
11-1.-Pitr:tt3mE
00606@e60
AP
ga
A:Wi tl'Y
0 St.
®109600
Nw7. O
=SIM;
(g.1
M.11
tr)
0
01000,114
0 00180 m
01000
0 00,
in1.0, .000
10
A00013. .011.1
mr. 0.*".
1
21.
.
M.11
cogZika
El
cociEd
IInmoisimmr=isEetai
nn11n122.1,,,
.
001/0
M./
0
Or/
0/003 11.41
MI IN.
01000
01000 Atte
010. ON
€10e •
EiR
0,1
WW
c,
ca"
1,1111-11
141 SWIM!
u SMI920 'WO
02A217510
2dniVt111943.1. 1231151H
ill
<a_A gi
1.4 1
xI
I
lllll
1
03A1130110 000/4 40
1N30113d %kW 2111
3WI1SI0W 1S31401 01 IS2110114 WOW 210011
xl 11131NO2
tit
11g123
S J
N„ 1
N.
00235:00.„_wrivEr
VMS
"Z
e-
0
▪
F
rt+-
tD
tir
q co crl
—115W9
YAM
N
-P
•Ed a .a
;11
N
g
a
C
`AA;
000
a
-P
11r"7*"
'.
NM IN
NM0 lllll
I*
/11n11
n••fla iwas
..33221"I" 0Y
0'
=zaigEsEaREEEE
10 0 47 S.,
0
q
MON ON
11n11,
OON ON
5
!NON ON
a
..aastassassEa- a 44
,1•1
a 4S
gr
l
asszczear---
1:4
tu,
g
.(-1
Ft2 Lo
• 1= F 0
0
O
INVII ON
um le
1-
•r1
ei7z285'
PTEEP
oi
Glom Lo.ra
n-
g
"'"Auma
"
..n0013
MV1-1,
'50
<
woi
"
L.0,7 •LIOt
nW
Usu. '41:t
111.
Nm
onEEnIIIMMEEIMEBEF•
oar.
rimag12992'
11=
1 0=
Aono,a
4n
o
Zi
4°z
CD
oV713
IN
x,:9 YIYY
Ul
t
009
1Z
^700=
Ofi;
4J t.
rt::
oN,16
▪
a00013
"
1—,-
ggs
1141
9 NJ am <6512S930 X 100
a wilco° Rernodwzi. 1S7H71H 4
0
'NO 141 Donna 03At0S90 000M JO
11433tad
1N31NOD 3rin1siow 1S31401 01 1931-101H WOti 30NVel
0) •
4
•-i•
4
w 0 n)
000 ]01401
N
I4
r.r%
-P
GSp
- o-1i,1
4VSES3
121!9•177.5tEEEEEEsap...
07.Ei
0
g
y NW, XILM
YI
0
i
•a
•
.:0•ZE
q
4-4
4-)
cd
.I 0014
.0
a
4
eel
a
el
'CI
cp
N 43 id
-4 E
mw
5.-
a
iri M
4-c
=MP°
aszliENP22P°
nsnoonjlfiWEfai,z,.
Nom
Bort
CH
43o
•
\
LLJ
6-1 LJ
S 0
.7
1–
E
11 1 ∎
efoe
CO
O
g
`47
•-••
I
I
tj XXX
eeeete,@(e
•el•
i
=
74.
...••n•••nn••••n::
II I . nnnn• •
.11
ZC•2
III
O
10
O
[1[11111111
c0
CC
O
CO
4
cV
0
*4'
cnJ
0
N.1
.
V)
U
O
to
esJ
Z
I
I
I
I
I
I
`t
1N33213d IN 31NO
Nosoni.
I
I 0
wirusiow
1
I—
-
44C
C1
4.
i tL, I
;0 I .1)
el
IN3Ond
` 1N31NO3 3 2ff11SIOW
NOSICIVW 1V
Airi"T
OO
1.t
:j
3
3;
3
O
N
N
3
NA
4
•
F1
N
3
V
1
I.
31
tl
AA 73
'.95
Oa
gv
Lo
tl
la
I !
O
:10 1
.t
1
3i
oM
A
1
la
OW
'0,10
'5
'44
11
Oq
O
a
tiq 214 t
atl
5
r
a
t 4
O
0 2
E.st
111
iaa
.h2
a
mR
a
OVPZILVWtttE
*1'
1;iiii:!4f
ptat2i"4:2
e-i-eeeq
ISO 4 laliE-Aaaa K
FS
222`2b12:q
.ctr.
Table 2.--Average moisture content of spruce
specimens in different parts of tile
wings.
: Average moisture content of spruce
specimens
Location of
observation
:June 26:Aug. 28 :July 23:Sept.10:Oct. 1
to : to
to :
: to
: to
:Sept.24:Sept.17:Nov.
5
:Aug. 21:Oct. 9
:Percent:Percent
East wing:
El, leading edge, near : 10.0 : 13.1
middle of span
7.3 : 10.1
E3, between spars, near:
middle of span
7.7 : 10.8
Ell,between spars, near:
wing tip
8.7
7.8 :
E5, trailing edge, near:
root end
:
West wing:
Wl, leading edge, near :
middle of span .
W3, between spars, near:
middle of span
Wll,between spars, near:
wing tip
W5, trailing edge, near:
root end
:Percent:Percent:Percent
:
6.3
:
3.8
:
5,3
:
5.3
:
3,3
:
6.1
1
4.9
:
3.1
:
4.8
:
4.9
:
3.1
:
4.5
9.7 :
13.9 :
4.8
:
2.3
:
4.5
9.0 :
12.4 :
5.7
:
3.9
:
6.8
8.6 ;
10.2 :
5,2
:
3.4
:
5.6
8.9 :
:
10.5 :
5.3
:
3.6
:
5.2
I
-RiFst-r-l-c-tati Mimeo. 1597
At Tucson
: At Madison
•
"
gg
:111.14.1tr.
r:555EFIF
7EF..1117gi
mag=MMD
1 !I
11:'
0. n0.0.0-00A
ggt“412
VI a
11
2.;*
0
o
0
g
"
r..gg2ggq
:22F2e5
H.E.E;;,14
E
„13,;,,
a
MAIO
un!...!4E.
„t5g?-.F.,
Pe
:4;
0
0
g
a "4:"."""'
o
O
E
Na::a
a
i1 WNWOON
O
ti
Fl EMU.
g . gl.gg
000
........
;
6 :1 ti
•
8!.7
p IF
• E.
tl
y.IF
. IR
rrp74!),
i!
W.0A.11.1P1AN
N .4NWWIJI0
O ,A*00...04
O
0
g
a
2
Y'l*:."*71
0 1.10-41.N0
t.,1?Trr,0!4
m m.mmOm
n-•
. . .
4
E
0,0,A0N-W10
a 9,010
Otz OV .0,-0
. . . .
as-i 0,010 n0
O
rlr”rn,
N ww.0000N
pO
•
N N000(PV
-"-
ti
P ON m 00W
OI
. . 0,0
. . .00:10
. .
CA, ON A.050.4
g
54561:1.Z8
OL0 .-.1l0030
•
N
.0
I R
WW
01..7W,ACm7.-0
ep
O
4 NO -1000
-11
'
0.-10-10.0
N
a' g.
tr
r
♦
1 -
E
a1 MPm-IPP
a 15-1
..••••
PV COV Co 4,0 r0
6 n,,mwym
!1!-Prrpr.,
OWNMWO
com*kmm6
Wail=
ZA66,6;.A61
rf":"°??P'Y
omww.u.010
W
Vy
yleyr
021.0-4m,0
-11 ONWNO0
.1V-4.POU.
6
3g
010 -3 Co. 0 06
.
0 0Y 1,0 *V 0
t;
0000100NOW1
?I:'e!"?'
W WOMVIVW
!"1:”2”1-"
P 4.1100%01/40F,
ri!,nmnir
W.O0W0,0
1i 1
I: r_r .
alcoCIZZrZ
O 11ir4I1Niu
•
;-
11 g vr
: vf
I P i!
fg
1
tflvPrr1/4"'
eoulm,o64
rif.rrrY.r
•nnn
-C 7
0
CA
•
In Jo- p
r ri
€-04
4:17=q
72
0
0
en
Cn
0
—9
ae
CA
Aa
z=,
N
.2
rz
3 3
1-1
M