HAVE YOU EVER WONDERED?
Why navigational lights are as they are?
How statute and nautical miles came to be?
Why aircraft captains sit on the left?
How dead-reckoning really came to be?
Why pilots use log books?
Where Patterns A and B for instrument training came from?
Why do transponders squawk.
SPINS WERE A ONE TIME THING IN 1914
How aircraft got their Red and Green running lights.
The Historical Process:
Where Left-handers Get Even
Different miles and how they came to be
It's about time
Way to Go
Buying the Farm
Why We Squawk
Measures
Shirt tails
THE LORAN SYSTEM
Aircraft position
Society of Automotive Engineers:
Markers:
Radio Marker
Fan Marker
Bone Marker
Z Marker
Trim Tab Inventor
Pitot tube inventor
SPINS WERE A ONE TIME THING IN 1914
An unheralded aviation pioneer is, British scientist, F. A. Lindemann.
"The Prof", as he was known, led a very checkered scientific and social
career from early WWI through WWII. He was an "idea man" and advisor
to Churchill for thirty years. He was a social butterfly and a scientific
gadfly in the opinion of more capable scientists. However, his place
in history could well lie in aviation and you never heard of him?
Born of German/American parents, he spoke heavily accented mumbled
English. He knew all the "right" British nobility and used their
influence to gain both position and prestige. In 1914 he attempted,
but failed because of eyesight, to join the Royal Flying Corps. He
then used influence to join the scientific staff of the Royal Aircraft
Factory.
In 1914 the "spin" was the most dreaded unintentional flight occurrence
which resulted in accidents. More to be feared than the more frequent
landing accidents. At least, landing accidents could be explained.
Once an aircraft was in a spin there was no way out of it. The spin
turns would increase in speed until the ultimate crash. All flight
instructors warned, "Get into a spin; get killed".
Lindemann initiated a study of the instrument readings and pilot procedures
that seemed to cause the stall/spins occurring during turns.
A letter to his father said, "Nobody can make out quite what happened."
Lindemann could find no apparent pattern as to when a stall or a resulting
spin might occur. A British naval pilot was said to have recovered
from a spin. If not known if Lindemann used this event to develop
an explanation, a theory, about spins. While never publishing his
study results, Lindemann gave many oral accounts of his findings.
The spin frequently occurred when the aircraft stalled in other than
an absolutely level condition. If one wing dropped any effort to
raise it would cause the other wing to flip over uncontrollably.
Even at high speeds, a tight turn might cause one wing to flip over and
cause a spin. Without any flight skills, Lindemann had worked out in theory
the probable forces which caused and existed in a spin. He also figured
out, in theory, the control movements required to counteract these forces.
His study showed that any instinctive response would not work.
The rudder must beheld fully against the spin while the nose was kept pointed
toward the ground. You could not pull back on the stick until the spin
stopped and flying speed was gained. His theory also seemed to indicate
that during the recovery the wings of the plane could be pulled off.
The way Lindemann used to test his theories was somewhat akin to a medical
researcher doing a self inoculation for a deadly disease.
He insisted that further study to prove the theory required that scientists
fly. He worked through and around the bureaucracy, used influence,
memorized the eye chart for his "blind" eye and learned to fly "poorly".
One 1914 flight of uncertain date justifies Lindemann's place in history.
One Fall day, he discussed his theories on spin recovery and the planned
experiment with observers at Farnborough Aerodrome. He would
be using a B.E.2 aircraft of most uncertain flight characteristics.
The fragile airframe was held together by a maze of wires and struts that
maximized a power off vertical speed of about 90 mph. He told them
he would deliberately do a stall spin. He certainly must have said
his good-byes. He departed and climbed for many minutes. Far below,
the observers saw him reach what must have been the B.E 2's service ceiling
of 14,000 feet. They saw the spin well before they heard the cessation
of engine noise.
Lindemann now began to test his theory. He pulled the power,
slowed the plane and entered into a stall. He held the stall until
the left wing dipped and the right wing flipped up for the spin entry.
A deliberate entry into a maneuver from which no one had previously recovered
and few had survived. A maximum test of accountability and courage.
Lindemann held the spin, intentionally or otherwise, until it was fully
established and then he initiated his unique recovery. A planned
application of control forces never before applied. He put in full
opposite rudder. Nothing happened. He waited. Still nothing
happened. He applied forward control pressure. He had
already fallen thousands of feet with no control effect discernible.
Was his theory going to fail at this critical moment? But the rudder
was starting to have an effect. The spin was slowing and finally
stopped. From the vertical, but without the spin Lindemann now had
to complete a recovery. Survival demanded that the pull out would
not remove the wings from the fuselage. Slowly, carefully the nose
rose and as it rose the aircraft slowed thus easing the stress on its components.
The first intentional spin and recovery. All that and survival.
Enough?
One such experiment and proof would have satisfied most people, but
not Lindemann. He climbed back up to altitude and did the spin and
recovery in the other direction. A theory twice applied and proven
to be a life saver. From that day on, a pilot's education has not
been deemed complete without spin training. (Except, of course, in the
U.S. by the FAA).
The British had a military secret. It combined two of the very
best qualities of military combat. Deception and survival.
A British pilot, when out-numbered or fearing for his life, could deliberately
enter a spin. To the enemy such a maneuver was not survivable.
The Germans would circle and wait for the inevitable crash of their 'kill'.
Imagine their chagrin, when the British plane would level out close
to the ground and scoot to safety. Indeed, the spin was often used
in WWI as a deliberate escape maneuver. It wasn't long before the
Germans discovered the deception and began to follow spinning planes all
the way to the ground. It is not known how the Germans gained the
secret of spin recovery. Pilots are known to brag about their flying
exploits while talking flying with other pilots.
Most great aircraft flights recorded in aviation history are about
distances, speeds and kills. Why not a special "save" category for
Lindemann along with Immelman? But again, wouldn't your entering
his name into your memory and applying his theory and practice to your
own "Lindemann" spin recovery be sufficient.
An aside: In WWII Lindemann served as Churchhill's scientific
advisor. He stood alone against all other British scientists in his
contention that the greater military potential lay in infra-red than in
radar. He lost the contest in WWII and radar saved Britain.
In 1990, Lindeman was partially vindicated. Desert Storm would not
have been possible without infra-red. A little known man of his time
and ahead of his time.
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How aircraft got their Red and Green running lights.
I have developed a possible sequence for the development of red and
green running lights on ships and aircraft. I would like to make
the following case, derived from a variety of sources, for what I believe
happened. All of the basic information is available in common reference
books but I can't find any record equating this knowledge to the final
conclusion.
The Historical Process:
Before the invention or application of a rudder to ships, they were
steered by large boards near the stern. These boards could be on
one or even on both sides of the stern. Gradually the boards, called
steerboards, came to be on just the right side. This eventually led
to the right side being called the starboard. The location of this
steerboard on the right meant that the captain maintained a command proximity
to this right stern position. The captain's cabin and Quarter Deck
position is on the right side of ships to this day. (The reason the
captain of an aircraft is on the left is a postscript)
To protect the steerboard, the placing of such a sailing ship beside
a wharf meant that the left side of the ship would be the side of choice.
From the left side another board was used for loading and unloading the
ship. This loading board eventually led to the left side of the ship
being known as the larboard side. The vocal distinction between starboard
and larboard in a high wind could easily lead to misinterpretation.
We must now move to the 15th Century. During this period England
and France were having one of their periodic disagreements. The English
decided to boycott French products including wine. Seeking another
source of wine the English turned to Portugal. Portugal produced
a red wine, which when fortified (made more alcoholic), was suitable to
the English taste. A trade agreement resulted between England and
Portugal with English cloth being exchanged for Portuguese wine.
The major port used for shipping wine out of Portugal at that time
was known as O Porto. O Porto is located in northwest Portugal and
is now known as Porto. The increased trade into this port could have
precipitated the need that "starboard" and "larboard" be modified.
The left docking and loading side of the wine trade ships at O Porto would
have made the change to the term "port" both possible, practical, and logical.
The combination of the Latin porto (to carry), the practicality of
docking to the left side, and need for a more distinctive term for the
left side of a ship leads me still further. It is not very difficult
to see how the word port became associated with the red of Portuguese wine.
There should be little doubt that the ships of the wine trade would acquire
a characteristic red color on the left side. The combination of the
left side of the ship being the side nearest the port or loading side,
the port of O Porto, and the red wine lead me to suggest such was the process.
Red along with the word port became the accepted identification for the
left side of a ship. The selection of green lights for the right
side follows more directly. I suggest that the red and green of the
Portuguese flag have become the running lights of the world. Thus,
even in its decline as a seafaring nation, Portugal still shows its colors
more than any other nation.
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Where Left-handers Get Even
Behind many of the things we do in flying lies a long history.
This often dates well before flying. Have you ever wondered why left
patterns are standard?
Before airplanes and cars, men rode horses. Most people are right
handed. As a matter of good practice weapons were carried on the
right side and kept available to the right hand. Since it was always
desirable to keep the right hand and weapon available, horses were mounted
from the left side. using the left hand for lift by pulling on the saddle
horn.
By happenstance, the military cavalry was the least dogmatic of the
services in all countries. When the military adopted the airplane
the cavalry was the natural choice for pilot selection. The cavalry
looked upon the airplane as another mode of transportation like the horse.
Best to be mounted from the left as by habit. Early cavalrymen nee'
pilots were even required to wear spurs. Did I really say the least
dogmatic of the services?
You will need to search old film very hard to see an old time aircraft
being mounted from the right by the pilot. I have never seen such.
In fact, most passengers mounted from the left. When aircraft were
designed for side by side seating, the pilot in command (captain) sat on
the left. The preferred pattern direction was left because that gave
the pilot better visibility. By convention the standard traffic pattern
is now to the left.
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Different miles and how they came to be
Under the Roman Empire, Rome became the center of the western world.
All roads led to Rome and all distances were measured from Rome.
The distances were based upon one-thousand Roman paces of the Roman
soldier. A Roman pace is equal to two of our steps and very near
64 inches. The Latin for thousand is mille from which we derived
the word mile. The distances along the Roman roads were marked off
from Rome by small obelisks or statues. Hence, statute miles.
The first paths for ships were called Porotan Charts. These were
lines drawn across the Mediterranean between the coastal ports.
Where many of these lines crossed the map makers would draw wind roses.
The wind rose initially varied but settled on the eight points. The
predecessor to the compass rose and our eight wind direction terms.
Thales of Miletus (640-546 BC) made a projection (use of shadows) of
the region where he lived. Hipparchus in the 2nd century B.C had
used sterographic (showing heights) and orthographic projections (perspective).
Eratosthenes in 3rd century B.C. calculated the size of the earth circumference
to be 24,000 miles. He developed a 16 point wind rose and use of
'degree". He also wrote a description of the known world.
Ptolemy, a 2nd century Greek, made a world map and made a world size
error when he calculated size of world's circumference to be only 18,000
miles. Eratosthenes' calculations had been lost to the western world with
the destruction of the libraries of Egypt. Copies of scrolls from
Eratosthenes were discoverd in Constantinople by Polish researchers but
it was over a hundred years before application was applied to nautical
navigation. This corrected size of the world was drawn on navigational
charts in 1669 by Jean Picard.
Ptolemy used the first conic projection plane map with the top as north.
This made possible drawing of rhumb (one direction) lines from point to
point on the globe. He devised the 60 minute and 60 second divisions
of the 360 degrees in a circle. A mile at sea, on this world of Ptolemy,
was essentially equal to a mile on the land. The length of a statute
mile was 1000 (mille, from the Latin) Roman paces. A Roman
pace is two of our steps. Each Roman road had occasional small oblisk
statues placed to indicate the distance from Rome much as Mexico today
does from Mexico City. Hence, statute miles.
A 1466 Chart of Nicolaus Germanus divided the degree into 60 equal
spaces called miles. This was based upon an earth of 18,000 mile
circumference and gave us a nautical mile the same length as a Roman statute
mile. Other cartographers including Hipparchus and Mercator
gave us a world with an overlying grid with numerical markings of longitude
and latitude. Gerardus Mercator (Gerhard Kremer), Flemish, in 1569 drew
world globe map with 180 degrees E/W longitude 0 to 90 N/S latitude.
He made errors which were corrected by Edward Wright who published the
computations required as "Meridional Parts" and made this knowledge universal.
In combination, we now had a world which could be mapped in degrees of
longitude and latitude. Each degree of longitude had divisions of
60 miles equal to a statute mile and each mile was again divided
into 60 units called minutes and each minute was again divided into 60
units called seconds.
This was the kind of map and scale used by Columbus. The navigators
of his time had not the timing device to make possible the exact determination
of longitude. The best 15th Century data available to Columbus came from
Ptolemy. The error by Ptolemy directly resulted in Columbus' declaring
that he had reached and was exploring India. Columbus thought he had sailed
through enough degrees of longitude to have reached India. He may
well have, had the world been 18,000 statute miles in circumference.
When the world was computed to be 24,000 statute miles in circumference
all the degrees and their divisions were longer and did not conform.
More accurate computation of the world's circumference kept changing and
finally came to 24,902 statute miles. The circumference of the earth
has always been measured as 21,600 nautical miles (360 degrees X 60 nautical
miles per degree). However, the individual nautical mile has
ballooned by nearly a third through this recalculation of the earth's size.
For many of the same reasons the U. S. has failed to convert to metric,
later cartographers decided to use statute miles for land and the expanded
nautical mile at sea.
Now we can see the background for the difference between nautical and
statute miles and Columbus' reasoning. We have Columbus sailing around
an earth at least 1/3 larger than he was led to believe. Based on
available knowledge Columbus was quite justified to assume that
he had actually reached and explored India.
For the navigator, it is very important that distance only be measured
along the lines of longitude which has evenly spaced tick marks throughout.
The elongated orange peel appearance of the region between lines of longitude
means that various latitude lines will have tick marks at differing intervals
although always 60 ticks per degree. Only at the Equator do the tick
marks correspond to the size of those along the lines of longitude.
Johann Henrich Lambert from Alsace devised the lambert conformal conic
projection in which the line you draw is the way you go. This is the charting
used on aircraft. As with any flat map of a round surface it has
areas of inaccuracy which increase in one direction or another. Sectionals
are most inaccurate (stretched) in the six inches at the top an bottom.
The center ten inches of the sectional for 5 inches up to five inches down
from center is somewhat contracted in size.
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It's about time
The first ship's time was kept with sand glass and the speed was determined
by counting oar strokes during a sand glass sequence..
A sailing ship's speed over a nautical a mile was, historically, measured
by means of a knotted (knots) rope tied to a log. A sand filled timing
glass would be used to measure the time from leaving the log dead (much
as a dead man might appear) in the water (dead reckoning) and the number
of evenly spaced knots passed along the rope. All of this would be
recorded in the logbook.
Since the chronometer was yet to be invented, sailors had no way to
determine longitude except by this dead reckoning. Within crude limits,
speed and compass indications could be used to determine estimated distance
and estimated longitude. Magellan in 1519 had access to charts,
globe, theodolites, quadrants, compasses, magnetic needles, hour glasses,
and timepieces. He was unable to determine exact longitude.
By the 18th Century a chronometer (first weighed over 36 pounds) was
used to get longitude. A chronometer differs from a clock or watch
because it has a temperature adjustment for greater accuracy. Captain
Cook in 1768 had three such clocks for his voyage. In 1779 he sailed
with 4 chronometers and a nautical almanac which enabled him to determine
longitude. The very first effort to make a calculator was financed
by the British to make the making of the nautical almanac easier.
The original design was completed in 1991 and found to work accurately.
Interesting to speculate where the world would be had it been completed
in the 1700s.
_______________________________________________________________________
revolutions per minute
First counted by paddle wheel ship captains.
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Way to Go
The pole star was recognized by the ancients as being a constant reference
for determining direction. The Norsemen in the 11th century
used a needle of magnetic iron inserted in a straw and floated on water
to point to the pole star. Petrus Peregrinus de Maricourt invented
the pivoted floating compass with lubberline and sight for bearing. The
modern compass is little more than one-hundred years old..
The compass card, due to wind rose origins is older than the magnetic
needle. A names of the cardinal compass points are from the ancient
Nordic terms for wind direction. Variation was understood by 1800
as a problem. Edmond Halley at end of 17th century mapped lines of
variation and drew isogonic lines (lines of variation) on his maps.
George Graham showed that variation was subject to diurnal (seasonal) changes
with variation being less in winter.
Deviation was written about in 1627 by John Smith as a problem encountered
through use of metal nails in his compass box. Captain. Mathew Flinders
in 1801-2 found way to correct by use of "Flinder's Bars as did Lord Kelvin
through use of Kelvin spheres. Placement of soft iron spheres at
sides of compass could be used to correct deviation.
The development of the gyro compass began in 1851 when Leon Foucault
used suspended cannon shot on a long wire pendulum to show the rotation
of the earth as well as the inertia of the free swinging ball. By
1852 he had created the gyroscope but had trouble applying continuous power.
By 1900 the electric gyroscope was invented by both Elmer A. Sperry and
Anschutz-Kampfe of Germany. By 1911 gyro compasses were in use soon
to be followed by gyro repeaters (selysn(sp) units) and gyro pilots.
First airborne gyroscopic instruments were tried on airships.
_______________________________________________________________________
Buying the Farm
In the '20s' barnstormers would travel the countryside to small cities
and set up an "airplane ride" concession from some farmer's field.
The pilot was expected to reimburse the farmer for any crop damage that
occurred. When a pilot incurred a fatal accident he was deemed to
have bought the entire farm.
_______________________________________________________________________
How we got Pattern A and Pattern B
Change to low cruise
` change to low cruise
prelanding check
emergency pullup
start normal 500fpm descent
500fpm descent
normal cruise level off approach speed
flaps
These patterns have been for many years a part of the Instrument Flying
Handbook as among the first lessons in acquiring the aircraft control required
for instrument flying. Prior to WWII few aircraft were equipped beyond
an airspeed indicator, compass, altimeter, and at most a needle and ball.
During WWII the gyroscopic instruments began to be installed on all
training aircraft. However, the use of these instruments was sadly
neglected for two reasons. First, the instructors had mostly learned
during an era of 'seat of the pants, wind on the cheek' flying. Secondly,
they were placarded to be caged during maneuvers.
Until shortly before the end of the war, instrument instruction, was most cursory. A pilot would often be sent overseas with fewer than ten hours of instrument flight instruction and perhaps another ten in a Link Trainer. Hundreds of pilots were lost because instrument skills were thought to be exclusively an airline pilot skill area. Airlines, viewing schedules as profits, had moved ahead in training and instrumentation.
A good case could be made for the statement that more pilots were
lost in WWII due to weather flying than due to combat. Hard at work
to correct this situation was a Joe Duckworth. He learned to fly
at Kelly field in the late twenties. As a reservist he flew
with Eastern Airlines and had acquired thousands of hours of instrument
time and an understanding of the importance of instrument flying.
Shortly before the war began Duckworth returned to active duty. He
was assigned as
director for training at a multi-engine facility in Mississippi.
Duckworth found flying was being taught as though there were no
gyroscopic instruments. Combat returns were indicating that
weather constituted a life and death hazard comparable to combat.
Duckworth initiated an instructional program which first evaluated flight
instructors and secondly standardized teaching programs. The most
immediate result was a 40% reduction in night flying accidents. The
relationship between the absence of visual reference at night and instrument
flying was quite apparent to Duckworth.
"Needle, ball, and airspeed" was the original instrument system.
From this, with the invention/installation of the artificial horizon
and directional gyro, Duckworth developed attitude flying instruction
based upon a scan of the full panel of instruments. The pilot first
needed to learn to fly the aircraft performance envelope using the
instruments. Then these skills were applied to the flight maneuvers
required to fly the radio range stations of the day. To train
pilots in flying this way Duckworth devised the "Pattern A", "Pattern B",
and the "Vertical S". Duckworth had found a system that would enable
survival in weather.
Next he developed a program for instructors. Their enthusiasm
and acceptance of the attitude flying system soon began to be felt and
heard throughout the training command. A head to head competition
between the worst of Duckworth's students with the best of the "needle,
ball and
airspeed" students was held. The results convinced, General
Hap Arnold the commander of the Air Force, to open an Instrument School
just for instructors.
Col. Duckworth became the commander of the base and its program.
For the last two years of the war flight instructors were sent to Duckworth
from all parts of the training command for a months duty. These instructors
in turn would return to base and establish training programs for more instructors.
By the end of the war no pilot was graduated from the Air Force Training
Command who was not proficient as an instrument pilot.
Why We Squawk
During WWII the British developed a top secret 10" x 10" x 10"
radar transceiver. It would respond to a radar interrogating signal
by responding with a coded transmission. A code would allow the land
based radar station to distinguish British from German aircraft on their
radar screen. The radio also contained an internal thermite bomb which,
when triggered by an inertial switch (crash), would destroy the interior
of the set. This was supposed to prevent German discovery of the codes.
(A reverse ELT?) The British code named the system Parrot.
The United States Army Air Forces version of the system was called IFF,
for Identification Friend or Foe.
As with many WWII developments, the IFF system was designed to
prevent a clever German ruse. The Germans were following the night
bombers back to England. German aircraft would join in the stream
of returning British bombers. They would wait until the bombers were
most vulnerable, just prior to landing, and then shoot them down.
Parrot allowed detection of these German aircraft since their (primary)
return would not have a distinctive code.
To control the operation of the airborne coded set to the
best advantage, the ground based radar station would radio instructions
regarding the operation of "Parrot". The aircraft would be directed
to "squawk your parrot", meaning to turn on the set for identification;
or to "strangle (not kill) your parrot" as a directive for turning the
set off. The power of the transponder signal would often hide
other targets.
The only vestige of this that remains today, other than the entire
ATC system itself, is the term "Squawk", as an ATC directive for operation
or code for the transponder. Old time ATC controllers may still have
you "strangle" your parrot (x-ponder)
Today the transponder usually has a four position switch—off,
stby (standby), on (mode A), and alt (altitude Mode C), a test button,
and ident (identification) button, a response light, and four selector
switches with numbers from 0 to 7. Certain aircraft letters and numbers
cannot be reproduced but frequently the discrete code can be seen to represent
a specific aircraft due to their similarity.
ATC has a system by which the code used on the transponder shows
a specific type of operation. Operations such as VFR without advisory,
VFR with advisory, IFR, specific airport operation, TCA, ARSA, Local IFR,
Tower enroute IFR, X-country IFR, emergency, hijack, and radio failure
all have differing first two digit codes which tell ATC controllers your
situation.
There are 4096 possible code selections on a transponder from
0000 to 7777. This is a Base 8 number system which is used by computers
as a short method of storing Base 2. Base 2 is the number system
of computers.
The four places of the transponder from right to left are 1's,
8's, 64's, and 512"s. We know it is a base 8 because the highest
digit is 7. The eight possible digits are 0, 1, 2, 3, 4, 5, 6, and 7.
Counting in Base 8 proceeds
as follows:
Base 10
Place Values 512 64 8 l
equivalent
0 0
0 0 = 0
0 0 0 1 = 1
(1 one)
Set as transponder
to
code numbers. 0 0 0
7 = 7 (7 ones)
0 0 1
0 = 8 (1 eight, no ones)
0 0 1
1 = 9 (1 eight and one one)
to
0 0 7 7 = 63
(7 eights, 7 ones)
0 1 0
0 = 64 (1 sixty-four, no eights, no ones)
0 1 0
1 = 65 (1 sixty-four, no eights, one one)
to
0 7 7 7 =
7 sixty-fours, 7 eights, and 7 ones)
448 +
56 + 7 ones =511
to
7 7 7
7 = 4095
4095 added to 0000 makes the possible 4096 transponder codes.
More than you ever wanted to know?
Emergency 7 7 0
0 = 4032 in base 10
Nordo
7 6 0 0 = 3968
Hijack 7
5 0 0 = 3904
VFR
1 2 0 0 = 640
Measures
As pilots we are, generally unaware and/or uneducated, as to the debt
that aviation owes to those scientists and mathematicians who preceded
the Wright brothers. The mathematics of aviation begins with the
prehistoric use of our hands which gave us the span as in wingspan.
Consider the beginning the numbering system. The Babylonians,
over 6000 years ago, added the use of symbols, 'zero', and place value
to make mathematics possible. From the Babylonians we acquired the
Base 60 numerical system used in telling time. This base sixty is
also part of our navigational system. Ever notice how easy it is
to do fractions in Base 60.
It is interesting to note that the sum-of-the-digits for every 45-degrees
all around the compass rose is the same. This is true no matter where
we start on the rose.
360 = 9
045 = 9
090 = 9
135 = 9
The Egyptians, not much later, devised a way of dividing the year
into twelve months even including the leap year. They followed up
with land measuring systems not unlike those used in modern map making.
The next major step in aviation measurement came from the Greeks about
2500 years ago. The Greeks sought rules for the way number-ideas
seemed to work. They applied a reasoning process to build on known
facts to reach a conclusion. They knew it as deduction. Some
flyers call it, albiet incorrectly, the origin of the term Dead Reckoning.
Actually it is a deductive system of navigation.
Dead reckoning is a not a corruption of deduced reckoning, the
term derived from the navigational practice of starting from a point (Buoy)
that was dead in the water. From this point the direction and time would
be used to deduce location along the route as it crossed longitudinal lines.
The Greeks developed axioms into theorems and proofs. They used
abstractions to illustrate the reality of the world. Such abstractions
pilots now call sectionals, charts, or maps. The Greek, Thales, demonstrated
five propositions which have become part of geometry or earth measurement.
A circle is bisected by its diameter. Whenever we draw a course
line we are bisecting a circle.
Equilateral triangles have equal sides and angles. Every time
we make a 45 entry to an airport, decide when to turn downwind and determine
the 'key' point to turn base we are applying our knowledge of equilateral
triangles.
A diagonal through parallel lines give equal opposite angles
A knowledge applied every time we enter on a 45 and enter
downwind.
A sphere cut by a plane always makes a circle. The sectional
chart used in flying is drawn from such a plane. The globe for a
specific chart area is given a cone for a hat. Then a plane is cut
through the cone and the globe at right angles to the vertical axis of
the cone. The lines of latitude and longitude are projected onto
the plane as are the lines making the map. Errors exist along the
top, bottom, and center parts of such a map.
Triangles having one side equal as well as two angles equal are congruent.
Euclid also collected all the math ideas he could such as all
right angles are equal, a straight line can be drawn from one point to
another point, and the sum of the angles in a triangle equal 180
degrees.
Archimedes was a mathematician as well as a creative engineer.
He used a screw shape in tube to move water. The movement of a propeller
through the air is such a screw. Early propellers were called air
screws. His use of pulleys and levers have applications in aircraft
control systems. Pythagoras with his followers discovered the roundness
of the earth, the numerical relationships of frequencies, and the Pythagorean
Theorem whose hypotenuse we fly during climbs and descents.
WWII navigation with sextant, chronometer, almanac, all of which
made possible finding a line of position using the celestial method of
Marcq St.-Hilaaire. Radio navigation uses this method of a line of
position with intersecting lines for a given position on the line.
Only a timing device is required be it a watch or DME.
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WHY PILOTS WALK FUNNY
Ever wonder why propeller pilots walk funny? They do. The P-factor explanation from the instructors handbook tells the instructor how to explain this to the student. It has nothing to do with how much liquid consumed? Part of the difficulty comes from having two or more generations of pilots, none of whom have had the opportunity to drive a team of Missouri Canaries. Mules that is. This educational and experience deficiency can be partially overcome while explaining the P-factor. Thereby leading to the ultimate answer of the initial question.
Start with an airplane which has the training wheel under the nose. A Cessna 152 will do. With all three wheels on the ground the student should be carefully walked around the propeller to note that, when the aircraft and propeller is horizontal, the blades each form approximately an 11 degree angle in pitch from the vertical. The airplane should be imagined as a wagon and the painted tips of the blades as harnessed to two mules of identical size and strength. In this configuration the wagon (airplane) would be pulled straight ahead until made to gee or haw. Gee meaning right and haw meaning left. O.K. so far?
Now have the instructor hold the aircraft tail down while the student observes the angle from vertical the pitch of each propeller blade. The left blade is near vertical while the right blade has doubled its angle. Now the airplane/wagon suddenly has two completely different mules. The left blade mule becomes of donkey size or less while the right blade becomes a dray that once pulled a beer wagon. Now which way will the wagon, nee airplane, go? Will it gee or haw?
More often than not our last two generations of student pilots
will chose the wrong direction. The odoriferous experience of mule
driving having been denied them. Using the wing struts to move the
airplane should show the student the error of his ways. Then it follows
as the night the day that in a climb attitude an appropriate application
of right rudder is needed to keep the airplane on the straight if not narrow.
Whatever it takes to prevent a "haw" Which, of course, leads us in
the great cyclonic circle to the answer of the initial question.
It takes a lot of "Gee" Leg to prevent a "Haw".
Shirt tails
There has been a long tradition in aviation related to cutting off
the shirt tails of newly soloed student pilots. One story has
it that the practice began because of the student need to clean his goggles.
Pilots had scarves to use in keeping their goggles clean but the
student had to use a shirt tail. The cutting of the shirt tail
was
giving the student the symbolic scarf of a pilot.
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THE LORAN SYSTEM
(I instructed LORAN at 58th Bomb Wing Training School on Tinian Island
of the Marianas during the last year of WWII)
Loran is a hyperbolic system of position fixing with long range
capability. Loran combines the words long and range. Loran-A
began as a naval shipboard system during WWII. The equipment was
reduced in size to about two units 14'x20"x24" which became the airborne
AN/APN-4. By the end of the war the APN-9 required only one such
unit. By 1990 the Loran APN (design) number was well into the APN-30's
and smaller than a cigar box.
The aircraft position is determined by timing the difference
in milliseconds it takes the signal to reach the aircraft from the slaveand
master stations. In WWII these had to be counted on a cathode ray
tube. Now it is automatically and continuously computed on a microprocessor.
Loran Stations transmit radio pulse signals with a wait time
determined by the range of the system. This prevents subsequent pulses
from causing interference. Such pulses can be of very high power.
Two loran transmitters, several hundred miles apart, made a master/slave
pair on the same frequency. The slave would not transmit until it
was triggered by the master pulse. It should be noted in passing
that there was no apparent effort by the Japanese to jam Loran frequencies
during WWII.
The Loran set would be tuned to a Loran master/slave pair and
could receive the pulses. The pulses would be shown along a cathode
ray tube (CRT) line with a space between to be measured as a difference
in reception time. By carefully adjusting the frequency of the electronic
sweep to the pulse frequency the two pulses could be made to appear with
the same space between them on the time base line. If the frequencies
were different the pulses would creep forward or backward. The initial
line could be greatly magnified and the signals could be electronically
superimposed by fine tuning the delay knob. Once the two signals were detected
and superimposed new switches brought up a CRT electronic clock.
Post WWII stations sometimes had two slave stations.
The CRT electronic clock divided the sweep of the phosphorus
ray across the tube into a series of spaced divisions much like a ruler.
The larger spaces were repeatedly subdivided and could be remagnified and
subdivided with additional settings. With training, the divisions
on
the scope could be counted down from tens of thousands to one millisecond.
A skilled operator could do the entire operation is less than one minute.
Aircraft position
It was now necessary for the operator to make reference to a
Loran chart. This consisted of a Mercator chart over printed with
hyperbolic Loran lines. they were drawn across the entire chart with
numerals to mark the calibrated milliseconds of different pulse times between
the master and slave stations of a given pair. At least two pairs
of stations were calibrated for each chart. The lines for each station
were of different colors. In 1977 there were still 65 Loran A chains
in operation. As of 1991 no A Chains are in operation in the U. S.
One of the difficulties with Loran-A, initially, was that from
a centerline between the stations there were always two possible lines
with the same microsecond difference. The operator had to know somewhat
his general reference to the station pair to prevent using the incorrect
hyperbola. Post-war Loran-A used a coded delay as well as odometer
to solve this problem and give instantaneous readings.
Loran transmitters would produce both ground wave pulses and one or
more sky wave pulses. It was necessary for the operator to distinguish
the difference by referring to pulse amplitude until beyond 1000 nautical
miles. Beyond this distance all waves would be sky waves. Weak
ground waves were to be preferred to sky waves since the charts were based
on ground wave differences. When sky waves were used a correction
table had to be incorporated into the chart use.
______________________________________________________________________
Society of Automotive Engineers:
In 1917 the SAE had an Aeronautical Division which diagrammed and identified
the stick controls and rudder used to control aircraft.
Altitude Control diagrammed the forward and back movement of
the stick to give up-down control through elevator movement. Balancing
Control diagrammed the left/right sides of machine down by means of side
movement of stick through aileron movement. Right and Left Control
was done with the feet through rudder movement. SAE had merged with the
Aeronautical Society in 1916 and has been instrumental in setting government
standards for aircraft construction, maintenance and safety.
Markers:
A 1954 edition of the Pilots Radio Handbook revised by the Civil Aeronautics
Administration describes the LF/MF (Low frequency/medium frequency) four
course radio range as a ground located radio transmitting facility which
defines four navigational radio courses which the pilot of an aircraft
can locate and fly using a receiver operating in the 200-425 kilocycle
band. This system was known under such names as four-course radio,
radio range, Adcock range, standard radio range, A/N range and L/MF range.
The last U.S. continental range was decommissioned in Maine about 1970.
The 'Radio Beacon" is a general term for LF/MF navigational aids for use
with a direction finder to provide bearing information.
Radio Marker
The Radio Marker is a fixed ground transmitter operating on the frequency
of 75 megacycles to provide definite position information to an aircraft
directly above it. A high directional signal is transmitteddirectly
above the ground antenna. The aircraft marker "marks" the passage
over the antenna by coded tone bursts and lights. Although all at
the same 75 megacycles frequency the different functions of the beacons
are determined by their locations, power output, coded signals, and light
color.
Fan Marker
Fan Marker (FM) at 100 watts emits a 3000 cycle tone in a elliptical
pattern. At 1000' it is 4 NM wide and 12 NM long, at 10,000' it is
12 wide and 35 long.
Bone Marker
Or Dumb Bell Marker because of its shape gives a more precise check
when exactly on course. At 1000' it is 3 NM wide in the center and
12 NM wide.
Z Marker
Z Marker or Station Location Marker is located in the center of a radio
range site and gives a positive indication of the cone-of-silence by radiating
a 5 watt signal vertically. Shows white light. These are still
in use in other parts of the world. ILS Outer Marker (OM) transmits
a fan about 4 ½ miles out on the ILS approach path. Shows blue light.
ILS Middle Marker (MM) gives fan about 3500' from approach end of runway.
Trim Tab Inventor
Also known at the servo trim was invented by Anton Flettner, a German
aeronautical engineer. He worked for the Zeppelin Company in Germany.
(Will try to find out if his invention installed on Zeppelin before airplanes.)
Came to U. S after WWII and worked for Navy. Died 1962.
First gyroscopic instruments were test flown on blimps.
First reversable propellers were installed on airships.
Pitot tube inventor
The pitot tube was invented by Francais Pitot, a French physicist and
dentist born in 1695. His tube was first used to measure water flow.
It measures the difference between ambient and dynamic pressures.
Only the very, very old or very, very new aircraft do not use a pitot tube
to determine airspeed. The pitot tube measures only pressure.
There is no air movement through the pitot tube.
First bomb dropped from an aircraft was in 1910 at Tanforan Racetrack near San Francisco.
First aircraft carrier takeoff occurred in San Francisco Bay.
First pilots license was issued to Glenn in 1911. Prior law was that of gravity.
First airmail flight and delivery was between Petaluma and Santa
Rosa.
three emergency landings enroute.
First gyroscopic attitude indicators were tested on Blimps.
Hundred Octane Aviation Fuel
Interestingly of all machines, only airplanes have their
own fuel.
In the late 1930s light weight and compact engines were being developed
with compressions ratios that required fuels not subject to detonation.
100 octane began as a scientific curiosity by blending 70 octane with chemicals
such as tetraethel lead and hydrogen to get the higher octane.
In 1938 an alkylation process by Humble Oil greatly increased
the possible
production of 100 octane. Cold acid alkylation made it possible
to raise 1943 production of 100 octane to 15,000,000 gallons per DAY!
However, full power engines still encountered detonation. The solution
was to use fuel additives that would become effective to prevent detonation
at full power operations but at lower powers were adjusted to lower octane.
100/130, 91/95, and 80/87 aviation octane fuels became the norm.
By mid-1940 all British fighters were converted to operate on
100/130. This change allowed manifold pressures to be raised from
42 to 54 inches. This gave every engine an effective 30% increase
in power. Now, tell me, what won the Battle of Britain.
The Lodestone
We do not know the why of magnatism. We can only wonder
why the earth is magnetic and why the magnetic poles do not coincide with
the true poles. Ancient iron workers had discovered and displayed
the powers of attraction due to magnetism. The origin of the name
seems to come from an area in Greece were lodestones could be found, Magnesia.
The first literary mention of magnetism occurs after 1180 when
Roger Bacon
used a needle in a straw to point to the North star.
Peter Peregrime wrote ninety years later than breaking a magenet gives
two magnets. He also noted that the lines of force of a magnet conformed
with the longitudional lines of the earth and focused at points he named
the North and South poles. This discovery preceeded by 300 years
the creation of a bar magnet.
The different positions of the magnetic poles to true poles were
first noted by the Chinese but came to the western world when Columbus
faced down his superstitious crew who were rebelious because of the compass
needle changing direction on passage of what we call the agonic line of
no declination. That declination existed was well known before Columbus,
but the existence of 'zero' declination was unique to the knowledge of
that time. This line was used by Pope Alexander VI to separate the
conflicting Portugese from the Spaniards in South America. This political
division was defeated when Magellan sailed from East to West thus circumventing
Alexander VI via the back door. Thus opened the world with magnatism
the key.
All this and so much, much more can be found at Whittsflying.com.