News Letter 1940 Jul-Dec - Air Force Historical Studies Office

homeon the stations of the Pan American
Airways. However, caution should
always be employed whenusing the radio
compass at these higher frequencies.
The indicator needle will oscillate
more and mountains will cause some
course changes. However, br, following
the indicator the compass w1ll always
bring the airplane to the station, although
the track may be devious. .'
Every radio compass when operating as
a compass Elmploysfull automatic volume
control. The equipment therefore when,
operat ing as a compass should not be >
used for aural radio range reception
since the automatic volume control cuts
a strong signal downand brings a weak
signal up, fhereby broadening the
course and making off-course sigpals
appear as on-course signals. For example,
the airplane maybe in the "A"
quBdrant. The "A" should be heard by
tlle pilot 'since it is much.stronger
than the "N." . Automatic vollime control,
however, will cut the "A" downand
bring the "N" UP.l..r esul.t Ing in .an oncourse
signal, 'men SllI'alreception is
desired tEe compass equipment should be
operated on "RE .ANT" or "REG .LOOP ."
In any position;. interconnected interphone
volume controls should be turned
full-on and the "audio" knob on the
compass control box adjusted for comforta:ble
level. " ." .. ~
. , Aural reception of simultaneous. radio
range signals .is only slightly affected
by automatic volume control, since the
carrier is always on; however, the cone
of silence Lsmade much sharper with a
leveling off of the build-up on both
sides of the cone. The compasses must
be operated on ''REC.ANT'' or ''REG.LOOP''
for @Podaural course definition of all
radio ranges of the.non-simultaneous
variety. .
, Conclusions
To sum up: Wheno:perated as a compass,
there is a sli@:J.td1stortion of recap- .
I rantal error. This error is caused by
the distortion 'of the radio waveby the
airplane structure. Q)ladrantal error
curves showthe correction which has to
be a,pplied to the indicated radio bearing
m order to obtain the correct. radio
bearing. On present type ~~~ses".if
the pilot does not have a antal;.
error chart 'available in tlie Birplatie,
he can point the air:plane toward the,d
station, bring the r1ght-left indicator
to zero. and read the ~etic 'compass"
On future :production of radio compasses
a device mll be provided for setting~
up the quadrantal error on the compass
itself so that a qua.dI:antal error chart
will be unnecessary after the curves
have been run and the error set up.",
. '. ---000--- ..• 1
, . , .'1'
MAJORroOLITTLEREl'tJRlilSTO .'-r '''fi,
ACTIVESERVICE :~"-f.'tn
• , Ut,.
. It 'was a matter of rejoicing smong.d
the old timers at Wri~t Field to see.
IIJimmy" Doolittle Major, Air Reserve',
in the cafeteria in uniform once more..
Major Doolittle has been called to one
:lear's active 'service with the Ail' :;,
Corps and reported on July 1 to the',
Supervisor of the Central Air Ocrps .Procurement
District for duty. Assigned
as an -Assistant Suoervisor of the. Central
Air Co:rlJsProeurement District ;'.:.he
will be 'stahoned at Indianapolis.,~
. Major.Doolittle' s career, both as' an
Air corps officer and as a Reserve. officer
since his separation from active
duty in 1930, is too well known.to 'need
recounting here. From the old McCook
Field ~s, he is rememberedasa test
pilot whowas always so anxious to try
out the newest and most radical designs
of aircreft coming to the Division.that
he could .searcelywait to lay hands on
the controls. .
Biographical notes .danced thro'wih at
random contain the following' colorful
lines: "First to Cross the U.S. in Less
than 24 Hours - September 5, 1922; "c ,
"Saved Life by Parachut e September I,
1929, Cleveland; II 'II Saved.Lile by. Parachute
.fune 1931, St. Loms; II "Demonstrated
Curtiss Pursuit Planes to .,,,:
ChiJ.ean Government, 1926; II "First American
flYer to Cross Andes in Plane, '.
1926; II TlFlys on Back Thro~ Sky; "'._
"AwardedDistiIJgl,lished JrlYlng Cross;.},
1929;" "Elected Presd.dent of the Institute
of Aerona;utical'Sciences, 1940."
These are but a few of the events ,that
flash across the "Doolittle" pages ...J
Not only did Major Doolittle,reCeive
a heart1.' welcomefrom all whoknew;him
at Wri6at Field, but all were .glad',at
the prospect of his being attlie"field
frequently in connectio~ with hi~"du~
tion of radio range silmals of simultaneous
ranges. ALWAYS USE MAXIMUM TI'TER-
PHONE VOIDMEJ AND MINIMUM .A!JDIO VOLUME .
ONCOMPASS .. To receive non-simultaneflUS
radio ranges :place on uBEC.A..~" or
REC.LOOP." ',Incia.entally, the automatic
volume.control feature which is now
a part of the present type commandset
is being eliminated on the new type
commandset, since this feature is a
source of danger when following the
radio range and has disadvantages in
trying to. tune in one of the two stations
which are close in frequency.
At the' time of installation all radio
compasses are .so calibrated that the
pointer is on zero for stations dead
ahead. 'To take side bearings it 'isnecessary
to take into account the quadhes
at the nearby stahon. .....c' d!lJ;
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V-8527 , A.C.