Ted Neale's Aircraft Instrument and Weather Notes

MNealeETH1395951-150731-052.pdf

Title

Ted Neale's Aircraft Instrument and Weather Notes

Description

Notes recorded by Ted Neale, during his training, about aircraft instruments and aviation weather.

Creator

Publisher

IBCC Digital Archive

Contributor

Frank Batten

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This content is available under a CC BY-NC 4.0 International license (Creative Commons Attribution-NonCommercial 4.0). It has been published ‘as is’ and may contain inaccuracies or culturally inappropriate references that do not necessarily reflect the official policy or position of the University of Lincoln or the International Bomber Command Centre. For more information, visit https://creativecommons.org/licenses/by-nc/4.0/ and https://ibccdigitalarchive.lincoln.ac.uk/omeka/legal.

Format

A book of 23 sheets of handwritten notes

Language

Identifier

MNealeETH1395951-150731-052

Coverage

Conforms To

Transcription

[underlined] Dyne [/underlined]
Dyne is that force which acting on a mass of one gramme will give an acceleration of 1cm per sec every sec
[underlined] Unit Pole [/underlined]
Where two exactly similar poles placed Icm apart repel each other with a force of one dyne, each is said to be a unit pole.
[underlined] Pole Strength [/underlined], is the number of unit poles contained in the pole.
[underlined] Intensity of a Magnetic field [/underlined].
If a single pole is placed at different points in a magnetic field it is subject to different forces, thus we say that the field varies in intensity,
[underlined] Magnetic Moment of a Magnet. [/underlined]
Is the measure of its tendency to turn or be turned by another magnet, it is the product of the

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pole strength & the distance between the poles.
[underlined] Hard & Soft Iron. [/underlined]
This terminology applies only to the magnetic qualities of the metal & not to their other physical qualities although it is often true, hard iron is iron which is difficult to magnetise & once magnetised it will stay magnetised. Soft Iron on the other hand is easy to magnetise, but which easily loses its magnetism.

[underlined] Permeability [/underlined]
Is the tendency of a magnetic material, when placed in a magnetic field to draw the lines of force within itself, since it offers less resistance to the lines of force than does the air. [underlined] Soft Iron [/underlined] is more permeable than [underlined] Hard Iron [/underlined]. a [underlined] soft

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Iron [/underlined] rod lying along the field of a magnet will be magnetised by induction, should the rod be lying at right angles to the field it will not be magnetised.
The Earth is in a magnetic field, caused mainly by an iron core in the centre of the earth, there are two external magnetic pole. N.M.P. HUDSON S.MP at Victorialand. The N.M.P. is blue in character and the S.M.P. is red. The Magnetic poles are always changing their positions & the magnetic field is constantly varying its direction relative to the true meridians.
The Earths field is strong enough to give directional properties to a freely suspended magnet, but it is not strong enough to actually move a magnetised body bodily. Let us freely suspend a small magnet within the

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terrestrial sphere it will be seen that the magnet indicates twice the magnetic lines of force at the locality at which we suspend it, & the direction that it indicates can be viewed in two planes, namely horizontal & vertical with reference to the Earths surface. In the horizontal plane it will indicate a direction which we can compare with the direction of the true Meridian or true North, while in the vertical plane the direction indicated will be in reference to the plane of the horizontal at the point of suspension. Thus it will be seen that the total strength of the terrestrial magnetic field can be resolved into 2 components that which acts in the vertical plane & that which acts in the horizontal plane, the respective values of which will depend upon the angle of

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dip of the magnetic lines of force in respect of the earths surface. Dip is the angle between the direction of the Earths field & the horizontal field, we have seen therefore that a portion of the total magnetic field strength is acting in a horizontal direction, this is the force which the navigator is interested in, that is the direction indicated in the horizontal plane, then we arrive at the magnetic compass which is simply a system of small magnets, usually four in number. Mounted in such a manner that it is free to direction in the horizontal plane only & will be influenced only in the horizontal magnetic field indicate the horizontal direction of the lines of force of that field at the locality in which it is placed. In short the function of the magnetic compass is to indicate direction of

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magnetic north which however is not necessarily true north. If therefore we know the angular difference between magnetic N & true N it will be easy to establish the direction of true N. The angular difference between T & M North in the horizontal plane is known as variation which varies with position on the Earth & is a known value for any position on the Earth.
[underlined] Methods of Conveying Variation on a Map. [/underlined]
1/. Isographs
2/. M. Compass Rose
3/. Diagram & Statement in words in margin of large scl map where variation is constant all over map.
When applying variation to bearings apply it from the position you are in, but in applying variation to courses except extremely long ones, apply the near variation between that at the point of

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departure & that at the destination, in each case make certain that it has been corrected for annual change.
[underlined] Deviation [/underlined]
Is the angle between the magnetic Meridian & the direction taken up by the compass needle, lying in a magnetic field, which is not coincident with the Earths magnetic field, if the compass needle is deflected to the right then deviation is termed Easterly or plus, but if the needle is deflected to the left then Deviation is Westerly or minus.
Aircrafts compasses are corrected for the major part of this deviation but even after correction, a certain deviation remains, this is found on various headings, & the results are put down on form 316 for Pilot & 316A for Obser compass. (Bearing. (Steering).


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Deviation is relative to the magnetic heading of the A/C.
[underlined] Magnetic Compasses [/underlined]
Types of Compasses in use.
P.4 Standard Pilots Type 4 magnets & Expansion Chamber
P4A as above but has a bakelite bulb floating ring & Grid ring
P6 Smaller edition of P4 two magnets & sylphon tube
P7 Constructed on same basis as P6 but is a vertical reader. it has a glass bottom on a sylphon tube
P8 Developement of P6, bakelite Floating Ring & Grid Ring
P9 Modified P8 with glass bottom on sylphon tube & can thus be read vertically
O.2 Standard Observers compass designed for taking bearings, has expansion chamber & 4 magnets
O6. Hand bearing compass, sylphon tube 2 magnets illuminated bowl, can also be used in place of a landing compass.
[underlined] Landing Compass [/underlined]
Two rather large magnets, sylphon tube sighting device

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[underlined] Compass Construction [/underlined] .
For aircraft compasses it is necessary to have a system which has the following essentials
[circled 1]. It should get off the mark quickly in a turn.
[circled 2] After the turn it should quickly return to normal, in other words the system should be dead beat, this is accomplished as follows.
[circled a] by means of damping wires attached to the system, the whole system being emerged in liquid.
[circled b]b. A large magnetic moment (magnet moment is power of the magnet).
[circled c]. A small moment of inertia, this is achieved by concentrating weight of the system as near centre as possible, by having 2 or 4 magnets instead of 1 large magnet.
General Description of magnetic system The system consists of a dome

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attatched [sic] to a small plate which is bent downwards so that small magnets can be accomadated [sic] in small holes punched out of the plate, also attached to the plate are 8 damping wires of which the N & S wire has a Mesathorium [sic] tube fitted along its whole length, with another small one attached at its N seeking end. The E & W wire also has a small tube, the magnets are S end heavy to counteract the wt of the tube at the N end. The whole system is made of German silver except the magnets which are 15% steel, there is no soldering, joining is done by units of screws. The mesathorium [sic] tubes are held in place by the black paint with which the finished system is painted, the damping liquid so that
[circled a]. It will act as a damping element
[circled b] It will reduce the weight on the system.
[underlined] Properties of the liquid [/underlined].
[circled 1] It must be cheap and easily obtainable
[circled 2]. It must be transparent
[circled 3]. It must have a small coefficient of expansion
[circled 4]. It must be able to stand up to a large range of temperatures.
[circled 5].it must not attack metal or boil of system.
[ circled 6]. It must have a low S.G.
A liquid possessing most of these properties is alcohol. It has a comparatively high coefficient of expansion, while its S.G is .816, moreover it attacks black paint & magnet system & eventually produces a sediment.

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A.S.I. CALIBRATOR MK 4
[diagram showing test apparatus]
Close drain cock. Pressure chamber screw loose. Level Instrument. Pour distilled water into tube until water is level to [symbol] on scale. Connect Rubber tube from B to ASI. to be calibrated. Screw up pressure chamber which exerts pressure on top of liquid column, through tube to ASI up to readings up to Max on the scale, then with the aid of Needle Valve back to minimum or zero.

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MK 4.E. MANOMETER.
[diagram showing test apparatus]
Connect pito tube of ASI by means of rubber tubing to nipple below connector box. screw pump connection onto pressure valve above.
[circled 2] Check level of Instrument. Check adjustment of scales to ensure reading of each tube is set at [symbol]

[page break]

Close release valve.
Turn change over cock right to connect to water anamometer [sic]. Pump slowly until water reaches first mark on scale. 40 miles p/h or knots Read ASI & record both readings Pump again until Reading next to be checked is reached & again take readings. Repeat until top of scale is reached. After taking the last reading on the water monometer [sic] turn change over cock to left so that the indicator is in communication with the mercury monometer pump till the reading of the mercury column is the same as the last reading of the water column. this will check the monometers against each other. Continue up the scale of the mercury column to the highest reading of the A.S.I. Repeat the readings in reverse sequence by regulating the pressure by the release valve.

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[diagram of aneroid barometer]
[underlined] ANEROID BAROMETER. [/underlined]
The instrument contains a round, flat, vacuum box, made of corrugated metal from which the air has been exhausted, one side of this box is attached to the outer case of the instrument, the case is not air tight so that the pressure inside is the same as that of the surrounding air. The pressure of the atmosphere tends to make the box collapse, but it is prevented from doing so by a spring to which the free side is attached. Decrease of

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atmospheric pressure reduces the load on the box & allows the spring to extend, the resulting movement which is very small, is magnified by a system of connecting links & transferred to a pointer registering on a scale which is graduated in terms of height. Incorporated in the Instrument is a compensator bar, composed partly of steel & partly of brass, which by reason of the different expansion coefficients counteract the effects of temperature changes in the instrument.

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Portable Calibrator MK I

[diagram of apparatus]
Set up on bench so that it has good top light..

Place altimeter in chamber with standard altimeter, set readings to correspond. if standard altimeter reads above zero increase pressure with bike pump. if reading is below zero bring it up by exhausting chamber, until it does. Readings should be checked every 1,000 ft, at a rate not more than a 1,000 ft per min, continue until top

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of scale is reached. Reverse the procedure by gradually increasing the pressure, by letting air in leak valve E.

[calculations of watch corrections]

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[underlined] Mags & Compasses. [/underlined]

[diagram of compass]
P4 has expansion chamber & 4 mags
P6 has Silphon [sic] tube & 2 mags
O2 is a hand bearing compass.
azimuth Bracket, with bearing card attatched [sic] to magnet system.

[underlined] Paragraph References [/underlined]
[list of chapters and paragraphs in unspecified publication]

[page break]

[calculation of time difference compared to GMT]

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[calculation of astronomical observations]
16 April 43

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[underlined] The Mercury Barometer [/underlined] Advantage
Accurate
[underlined] Disadvantage [/underlined] Can be [illegible], fragile & has to be set for every new [illegible]
[underlined] Variation of Pressure [/underlined]
[illegible]
[diagrams of winds in N and S hemispheres]

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The closer the Isobars the stronger the wind.
Winds are measured with an anemometer.
[underlined] Beaufort Scale [/underlined]
[circled 1]. It relates the speed of the wind to its effect on the objects.
[circled 2]. It can be applied when no instruments are available.
[circled 3]. It facilitates the plotting the wind speed on a weather map.
Pilot Balloon. Measuring Upper Winds
Smoke Puffs
Cloud movements
W/T Balloons

[underlined] Value of knowledge of Upper Winds. [/underlined]
[circled 1]. Economy in time & fuel
[circled 2]. For navigation
[circled 3]. May indicate pressure distribution at 1500 ft.

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[underlined] Backing & Veering of Wind. [/underlined]
[diagram]
[underlined] Gusts [/underlined] are sudden changes in wind speed and direction, caused by surface irregularities
[underlined] Visibility [/underlined]
[underlined] Code [/underlined] [underlined] Distance [/underlined]
9 31 miles Excellent
8 12 1/2 ‘’ V Good
7 6 1/4 ‘’ Good
6 2 1/2 ‘’ Moderate hazy
5 1 1/4 ‘’ Poor
4 1100 yds Mist
3 550 ‘’ Fog
2 220 ‘’ ‘’
1 55 ‘’ ‘’
0 0-55 ‘’ ‘’

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[underlined] Causes of Obscurity. [/underlined]
Moisture
Fog or Mist
Cloud
Precipitation
Spray

solid Particles
Dust
Smoke

Radiation Fog (LAND)
Formation of Radiation fog. Moist Air, a high dew point, & clear sky, allowing free re radiation of heat at night, Earth cools, cools air above it & when it cools below Dew Point condensation will occur, water droplets will be formed, a light wind 3 – 5 miles ph, to cause slight turbulence, spreads moisture, you get fog. [circled 1]. There will be an inversion. [circled 2]. The fog tends to collect in valley & hollows.

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Dispersal by.
[circled 1]. heating after sunrise, fog evaporates into warmer air.
[circled 2]. An increase in wind strength, carries fog up to form strato-cumulus at top of inversion.

[underlined] Movement Fog. [/underlined]
Moist air moves over a cold sea surface cools below dew point, Condensation, water droplets, fog. Depth increases with time, dispersed by increase in Wind Strength, a change in Wind direction.
[underlined] Cloud. [underlined] is composed of water droplets suspended in the atmosphere
[underlined] Conditions for Formation. [/underlined]
1/. Moisture
2/. Condensation Nuclei.
3/. Cooling by rising.
[circled 1]. Convection currents cause by surface heating.
[circled 2]. Mechanically over mountains or cold air.
[circled 3]. Turbulence

[page break]

[underlined] CLOUD DESCRIPTIONS. [/underlined]
[table of cloud types, heights and descriptions]

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[underlined] Effect of Ice Secretion. [/underlined]
I. Alter Airefoil [sic], less lift
II. Iced up carb, effect engine,
III. May effect Controls
IIII. On airscrew, sling lumps of ice about
V. Freeze up windows. Vision blotted.

Watch Temperature in cloud.
Descend to warmer levels, or else climb out of cloud, if you meet the other clouds, climb into the ice crystals and they are CIRRUS (STRAT & CUM0, [illegible] are not dangerous.

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[table describing hazards of being in clouds]

[underlined] Aviation Weather Report. [/underlined]
111 Cl Cm WW Vh Nh DD F W N
111 – No of Station
Cl Form of low cloud
Cm ‘’ ‘’ medium ‘’
WW present weather
V horizontal visibility from point on surface.
h. Height of low cloud in feet above the surface (aerodrome)
Nh Amount of low cloud
DD. Wind direction 02 to 32
F Wind force by Beaufort Scale
W. Past Weather.
N Total Amount of Cloud.

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[underlined] Synoptic Weather Report. [/underlined]
[diagram of weather chart symbols]

[underlined] Low Cloud [/underlined]
[table showing symbols for different cloud types]

Ops Value of clouds how heap clouds are formed. Fog

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[diagram of typical weather chart]
[diagram of cloud formation]
[diagram of inversion]

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[underlined] Cumulonimbus [/underlined]
1/. Especially violent heaps
2/. very poor visibility
4 Hail
5/ Lightning
6 Squalls

[underlined] Precipitation [/underlined].
Rain
Drizzle
Snow
Sleet Mixture of Snow & rain F.P. near Earth
Hail. originate as Ice Crystals, snow coming thru Super Cld water, gathers size & suspended by violent Up Currents & when it gets too heavy it comes down.

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[underlined] Altimeter [/underlined]
MK XIII Isothermal
L.R. 1013.2 mbs 10C. Temperature Changes.
M XIV Kollsman Sensitive Altimeter (ICAN).
1013.2 mbs - 15C
Lapes [sic] Rt 1.98C / 1000 ft – 36090 ft - 565C

[underlined] Aireys Rule [/underlined]
[underlined] Setting Kollsman AltifurRing [/underlined]
1/. Set to Pr of Aerodrome set on Altir & Alti will read 0 at aero & in flight will read ht above Aerodrome.
2/. Set to ht of Aerodrome should indicate MSL pressure & vice-versa. In flight ht above M.S.L.
[underlined] Q.F.E. [/underlined] Request for Station level pressure.
[underlined] QFF. [/underlined] Request for pressure reduced to M.S.L. (according to ICAN Law) accompanied by Ht of station

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[table of pressure differences at varying heights above MSL]

[underlined] Diurnal Variation of Temp. [/underlined]
Plot the temperature for the day, the diurnal variation is the difference in temperature at different times of the day.
[calculation of diurnal variation]

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E. J. H. Neale. (L.A.C. 1395951)
Ex – [underlined] (Woolwich Arsenal) [/underlined] apprentice.
Home Address. 1 Joan Crescent. Eltham S.E.9 London England.
Present Address 48 Air School, Woodbrook East London. South Africa.

[page break]

[underlined] Inversion [/underlined] an increase of temperature with height up to a certain point.
[underlined] The Effects of an Inversion. [/underlined]
[circled 1]. It prevents convection [circled 2] Very smooth flying conditions [circled 3] An Inversion will trap impurities in the air [circled 4] Poor Visibility.
[underlined] Instability. [/underlined] Unstable air is air which is warmer than the surrounding air & therefore tends to rise.

Stable air is colder than the surrounding air & therefore heavier.

[table of heights and temperatures]

[underlined] Atmospheric Pressure. [/underlined]
Wt of air per unit area.
[underlined] Standard Atmospheric Pressure. [/underlined]
1013.2 mbs at Latitude 45, Temperature 0C
[underlined] Advanatages of an Aneroid Barometer. [/underlined]
Requires no liquid, Compact, Portable, can be used as a barograph or altimeter. [underlined] Disadvantages [/underlined] It does not measure pressure on the [illegible] comparison with a mercury [illegible] mechanical defects. [circled 3]. There is [illegible] of sensitivity.

[page break]

Relative Humidity varies with Temperature.
[underlined] Dew Point [/underlined]. is the temperature at which the air would be saturated. If the temperature falls below dew point condensation takes place
[underlined] Temperature. [/underlined] is the degree of heat in a substance.

The Stevenson Screen, is a housing for measuring instruments, it is to protect [illegible] direct rays of sun & from the [illegible] of wind, also to ensure that [illegible] air is always flowing around [illegible] air.

[illegible] lapse rate is a change in [illegible] taking place in the gas [illegible] the addition or abstraction of [illegible] outside sources.

[table]

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which its influence is felt.

[underlined] The Line of force. [/underlined]
The line of force is the direction in which a red pole would move if free in a magnetic field . They never meet & never cross.
[underlined] Methods of Magnetising & Demagnetising [/underlined]
[underlined] By Vibration [/underlined] Place bar in North South line and hammer
[underlined] Heating [/underlined] Heat to red heat, place in North South line to cool.
[underlined] By Stroking [/underlined] Bar to be magnetised is stroked with another magnet as per diagram

[diagram]

[page break]

[underlined] Inversion [/underlined] an increase of temperature with height up to a certain point.
[underlined] The Effects of an Inversion. [/underlined]
[circled 1]. It prevents convection [circled 2] Very smooth flying conditions [circled 3] An Inversion will trap impurities in the air [circled 4] Poor Visibility.
[underlined] Instability. [/underlined] Unstable air is air which is warmer than the surrounding air & therefore tends to rise.

Stable air is colder than the surrounding air & therefore heavier.

[table of heights and temperatures]

[underlined] Atmospheric Pressure. [/underlined]
Wt of air per unit area.
[underlined] Standard Atmospheric Pressure. [/underlined]
1013.2 mbs at Latitude 45, Temperature 0C
[underlined] Advanatages of an Aneroid Barometer. [/underlined]
Requires no liquid, Compact, Portable, can be used as a barograph or altimeter. [underlined] Disadvantages [/underlined] It does not measure pressure on the [illegible] comparison with a mercury [illegible] mechanical defects. [circled 3]. There is [illegible] of sensitivity.

Collection

Citation

Ted Neale, “Ted Neale's Aircraft Instrument and Weather Notes,” IBCC Digital Archive, accessed October 22, 2020, https://ibccdigitalarchive.lincoln.ac.uk/omeka/collections/document/16391.

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