Notes on valve timing, pages of calculations, notes on aircraft fuel, diagrams and various other aircraft systems.






Multipage notebook


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 and





[This Notebook has been written using the right-hand pages only, right to the end and then turned over to continue back on the opposite pages, therefore this transcription follows the same format]



Form 714.


Rough Notebook for use in Laboratories and Workshops.

T. 3350 Wt. 2807 625,006 Bks. 8/42 E.J.A. & S. Ltd.

[Page Break]

Average Stroke on Aero [deleted] [indecipherable word] [/deleted] Eng’s 5 3/4" to 7‘ [sic]

Bore 6” average Average bore Ratio 6-1

Compression Ratio = [Calculation]

Hercules Engine Ratio 6 3/4 – 1

[Underlined] Value Timing [/Underlined]

Angles taken are between Crank Web and Vertical. Figures for Merlin IVO 31° before TOC. IVC 52° ABOC. 19 BTDC always EVO 72° BBDC EVC 12° ATDE. Valve Load. Valve Log. Together valve overtop.

[underlined] Sleeve Valve [/underlined]


Steel sleeve with 4 ports 3 inlet 2 outlet

[Page Break]

Conversion from Centigrade to Fahrenheit

F Boiling 212° F Freezing 32°
C Boiling 100° C Freezing 0°

180° F = 100° C
9/5° F = 1° C
1° F = 5/9° C


[Page Break]


1Cl Water through 1° F = British therm unit
1Cl Water through 1° C = Centigrade Heat Unit

1BTU = 5/9 CHU ICHU = 9/5 BTU


[Page Break]

[underlined] Aircraft Fuel. [/underlined]

Must be anti detonating under high pressure
Must be measured by butane Number 100bu Standard
Must be volatile or evaporate easily vapour is initial. 60°C to 180°C liquids evaporate [indecipherable word] in fact. 200 or more liquid in Petrol. Flock point is point at which petrol flashes with [indecipherable word] light temperature. Flame Ratio High Calorific Value is measured by that given off by burning [indecipherable word] Petrol, in CHU or BTU.

[deleted] Calorific [/deleted] Low Freezing Point must be below 60° C.

Latent Heat of Vaporization, is amount of heat required to vaporize. specific gravity = fuel/water 1 gall = 10lb

[underlined] No Acid or Gum Product or Burning. [/underlined]

Anti detonating
High Octane
Volatility Qualities required in Aero Engine Fuel.
High Calorific Value
Low Freezing Point
No Acid or Gum Products.
Must Have High Specific Gravity.

[Page Break]

65% Extra Ethyl Lead raises Octane Value of Fuel

30% Echybre [sic] dibromide corrects corrosion on exhaust valves of above

5% Dye for indication purposes. [inserted] Lead dibromide being a vapour.

100% dope = .1% or 1/1100 in fuel.

Properties of fuel in order of importance.

(1) Octane Number – Resistance to obstruction

(2) Calorific Value – High as poss to give large amount of heat for given weight of fuel.

(3) Volatility – Ability to vaporize – the boiling point being a reason for this. Should be as high as pos but not so as to give difficulty with storing, Vapour locks etc.

(4) Latent Heat of Vaporization – Amount of heat required to change 1lb of the liquid into vapour without raising the temperature. This value should be high, to give a good internal cooling effect in engine.

(5) Low Freezing Point – Fuel must remain liquid under all operation conditions, for this the freezing point below -60° Cent is usually stipulated.

[Page Break]

(6) Low gum or acid content. – Gummy substances tend to stick or clog piston rings and acid would cause corrosion.

If there is any choice, a high specific gravity is desirable.

All liquids in fuel are Hydrocarbon. Alcohol contain Oxygen and is not a Hc. 15 part of air to 1 of fuel by weight air contains 3 parts of Oxygen.

Hydrogen & Oxygen (H2O) = Water formed by burning

Carbon & Oxygen = Carbon monoxide (CO)
Carbon dioxide (CO2)

Complete Combustion = Water & [indecipherable word]

1 part of fuel burnt forms nearly 1 part of water as vapour.

Alcohol good for (1) & (4) poor for (2).

[Page break]

[underlined] L U Cort AVT 32 [/underlined]

[underlined] Needle Checks & Settings [/underlined]

[/underlined] The Boost Enrichment Needle. [/underlined]

Correct Artificial Boost rig and carry out following.


[underlined] Altitude M/C Needle [/underlined]

Get Barometer pressure of day (.1 knot [indecipherable word] of [indecipherable word] will alter projection 4/000.


If the Linkage gives .06 ploy – [underlined] renew [/underlined]
One complete turn will alter needle by .09.

[Page Break]

[underlined] Stromberg Adjustments [/underlined]
(1)Throttle Stop – Flow Running (By Elective Screw)
(2) Mixture Strength – Slow Running (By Screw on Side)

[underlined] Starting Engine fitted with Stromberg [/underlined]

(1) Turn on Petrol
(2) Set M/C lever to 1 Cat Off positive & set Throttle lever slightly open aprox [sic] 12,00 Rev P mt.
(3) Raise Fuel Pressure to 15 lb [symbol]”
(4) Prime Engine approx 6 pumps
(5) Switch on mags and Starter mag.
(6) Press Starter Button
(7) As soon as Engine fires move MC Lever to auto Rich
(8) If engine fails to pick up, return MC Lever to IC and repeat above procedure

[underlined] Priming Stromberg. [/underlined]

When a carb is first fitted to an engine it is empty of fuel [symbol] (1) Turn on petrol and set MC lever to Auto Rich (2) Raise fuel pressure to 10lb [symbol]” (3) Watch spay nozzle in induction pipe and continue priming until pure petrol issues from nozzle.
(4) Set M.C. Lever to I.C.O. when satisfied all air has been [indecipherable word] from Carb.

[Page Break]

If U have carb turned negative G which has been replaced by Anti G.

[underlined] Mags [/underlined]

[underlined] Faraday Law. [/underlined]

Any wire or conductor moving in a magnetic field so as to cut the lines of force will have induced into it an electric current, provided the wire is part of a closed circuit.

[underlined] [indecipherable word] Low [/underlined]

Any wire or conductor carrying an electric current generates around itself a negative field which increases or decreases with the strength of the current, where the current crosses the negative field collapses and closes to [indecipherable word].

[underlined] Lenz’s Law [/underlined]

Every induced current opposes is some way the charge causing it.

[Page Break]

Magnetism is the property passed naturally by Magnetite (FE304) of attracting small pieces of iron and steel. The principal magnetic substance, that is those which can be magnetised to a lesser or greater extent are iron – steel – nickel – cobalt. Steel may be made almost non-magnetic by alloying it with 11-13% manganese. Non magnetic Steel is necessary for the spindle carrying the iron indicators of the Polar Inductor Magneto. Soft Iron is easily magnetised by surrounding it with a coil of insulated wire carrying an electric current and so forms a powerful electro magnet which loses its magnetism as soon as the current ceases. Steel is more difficult to magnetise and requires a greater current but it retains its magnetism. The retentivity of steel is greatly improved by alloying it. Chromium, Tungsten, Molybdenum & Cobalt. Iron almost free from Carbon alloyed with Nickel & Aluminium forms the basis of “Alnier” which retains its magnetism to a high degree.

[Page Break]

[underlined] Faraday Ring Equipment [/underlined]


Proves that a collapsing magnetic field will cut wire quickly and therefore result in more current than a field which is building.

[underlined] The Rotating Armature Type [/underlined]


[Page Break]

[/underlined] Construction of the Primary [/underlined]

The Primary Winding is wound around the iron core which is previously insulated by wrapping of oiled silk. The primary wire commences from a soldered nut on one of the two metal plates. 22 SWG is used and there one about 140 turns, this wire is insulated by a special varnish and a wrapping of oiled silk goes between each layer. A small [deleted] motor [/deleted] [inserted] systo [/inserted] flex tube goes over the other end of the primary and is carried to the back of the contact breaker assembly and contact is made between the primary and the contact breaker by means of a spring tongue.

[underlined] The Purpose of the Primary [/underlined] is to protect and maintain the strength of a magnetic field, until it is required to collapse.

[underlined] The construction of the Secondary [/underlined] approx 40 SWG. 7,000 turns. The start of the Secondary is taken from the primary winding (before the conductor) The joint between the two is varnished & soldered over and the Secondary is then wound on, being stepped and layered with oiled silk. At the termination of the secondary winding a thicker wire is joined to it and this wire is further insulted by means of a

[Page Break]

of a systo-flex tube. Contact is then made with the distribution rotor arm by the median of a carbon brush.

[underlined] [Indecipherable word] – Construction & Working Principals. [/underlined]

2 Types – Monobridge used on modern magnetos Consists of laminations of mica & tinfoil – mica is good insulator & heat resisting. Another type used on American & German Mag’s consists of rolled tinfoil & wax paper and is known as cylindrical type. [underlined] Monobridge Type [/underlined] Consists of one layer of tinfoil and one layer of mica and so on.


[underlined] Why fitted. [/underlined] It only functions when the points are open. The pressure of current tends to flow across the points when they commence to open, the condenser affords an easier path and therefore the current taking the path of least resistance will flow into the condenser in preference to jumping the points, therefore the condenser prevents arcing at the points and assists in accelerating the collapse of the primary field.

[Page Break]

As soon as the points close the condenser discharges and this assists in building up the magnetic field by counteracting the self induced current which is formed when the field collapses.



The Con B Unit is the nerve centre of the Mag. Check the prong for good [Indecipherable word] location in the C.B cover. Check main spring for signs of blueing, corrosion and fatigue. Check gap between points and point surfaces if necessary reface using special jig. Check pivot for signs of wear. Check fibre heel. Check insulation of insulated carrier block using [indecipherable word], check gap between heel & buffer spring 6 & 8 about.

[Page Break] [Notebook flipped over at this point]

[underlined] Last 3 figures on [indecipherable words] = Last three on mag. [/underlined]

[underlined] The distributor. [/underlined]

Baklite [sic] moulding housing metal segments and connections for leads to plugs in the distributor will be found correction from H S [indecipherable word] or Booster Coil, also small ventilators. The purpose of the distributor is to distribute the sparks to the cylinders in correct firing sequence.

Ventilator (Gauge) prevent ionisation of the air and acts as a flame trap


Wash mag is petrol – water 75° – water 75° dry do not use paraffin.

[underlined] Distributor Rotor [/underlined]


[Page Break]

[underlined] Distributor Rotor [/underlined]

No of degrees of retard on H.S Brush can be measured by twice no of degrees between H S and Main. i.e. [Diagram] Main fires 30° BTDC – H S fires at T D C.

Gas formed by sparking in Rotor arm Chamber is Ozone or Nitrogen Pertoxide [sic] caused by Ionisation of air.

Deppresion [sic] between brushes of Rotor Arm is to [indecipherable word] surface area and thus prevents sparks tracking.


Polar Inductor gives 4 sparks per rev
Rotating Armature gives 2 sparks per rev


[underlined] Diagram showing 1/4 rev of Mag. Inductors. [/underlined]

[Page Break]

[underlined] MICA TYPE SPARKING PLUG [/underlined]


[Page Break]


Polar Inductor magneto. Two bar inductors type Diagrams showing flux reversal in half revolution of inductors.



[Page Break]

[underlined] Sparks per rev separately. Double flux [/underlined]

Watford NG2 Strobe 1 & NG 18 Strobe 1

[underlined] Identification of Magneto’s [/underlined]

First Letter – “C” denotes B.T.H.
N denotes North Bros (Rotax)
F denotes Simms.

Second Letter S denotes Spigot Fitting (90 MM)
T denotes Spigot Fitting (75 MM)
A denotes Base Mounting (Selector Found)

Third Letter T denotes Polar Inductor
E denotes Rotating Magnet

Followed by a number denotes No of [deleted] cylinders [/deleted] segments in distributor.

If followed by “S” denoted Screened (all modern mags are screened.

Next – Type or modification number [inserted] except BTH [/inserted] who put it after their C.

[Page Break]

Double Flux Type denoted by –

BTH [symbol] E – E (Example CISE-ES)
ROTAX [symbol] G (NG18/1)

[underlined] BENDIX IDENTIFICATION [/underlined]

[underlined FIRST [/underlined] “S” – Single Flux
“R” – Double Flux
[underlined] NEXT [/underlined] “F” = Flange Fitting
“B” = Base Fitting

[underlined] NEXT [/underlined] Number of Segments

Followed by “L” Left hand Rotation
“R” Right hand Rotation.

Possibly followed by “N” denotes Adjustable Contact Breaker Points (ADV/RET)




[Page Break]

[underlined] Multi-Lobe Contact Breaker Cons [/underlined]

Test for Continuity with lamp & battery.
Correct Megga to bore wire & insulation, if megga registers anything but infinity, insulation is faulty or broken.

[underlined] ELECTRICS [/underlined]

V – VOLTS = Pressure [symbol] – Ohms – Resistance
I – Amps = Current W – Watts – Power


Series decrease – Parallel increase – current.
Primary cells can only be used once Secondary cells can be recharged Plate in accumulator mode of + Red Lead (Lead Peroxide) – Sprogg Lead in Sulphuric Acid varies between 2 & 2.2 volts
Commutator – Copper plates insulated first each [indecipherable word] by mica.


[underlined] TWO WAY ROTOR [/underlined]

[Page Break]

Current generated depends on (1) Field Strength, (2) Speed of Rotation
Shunt wound generator (Parallel) [Diagram] [underlined] Residual Magnation [/underlined]

Carbon Pole Voltage regulator
Resistance of single react acid cell = .01 armature is .08 [Diagram]


Generators are fitted to supply all the electrical services and to charge the accumulators when the engines are running at speeds of between 1750 – 1800 and above R.P.M. Accumulators are fitted to supply all electricall [sic] services when generators are not in use. Voltage regs are fitted to keep the voltage constant at 29v with varying engine speeds. [indecipherable words] are fitted to connect the generator to the accumulator, when the voltage of the generator reaches 27v and to disconnect them when the generator voltages fall below the accumulator voltage.

[Page Break]

Navigation Lights (1)
Formation Lights (2)
Upward and Downward Identification (3)
Landing Lights (4)
Heated Pressure Head (5)
U/C Warning System (6)
Dinghy Release (7)
Graviner Fire Exting Circuit (8)

(1) They are fitted on Wing tips & Tail.
Red – Port 110° 20W Green 110° 20W Tail White 140° 10W
1 Switch in cockpit.

(2) Filled in Trailing Edges [Diagram] Blue. Can be Morsed.

(3) Upward 16W Downward 35W Yellow if 3 Red Green can be morsed.

(4) Fitted 2 side by side 240W or 350W outside outer engine slightly under plane – moveable.

(5) Fitted underneath nose on [indecipherable word] engine peto [sic] head [indecipherable word] I A Speed – Altimeter – Rate of [indecipherable word] dial. [indecipherable word] wing.

(6) Consist of Indicator in Cockpit R & Gn lights up & down. With [indecipherable word]

[Page Break]

(7) [Diagram]

(8) Bottle Methyl Bromide diluted to spray over engine

(9) Detonator Circuit R3003 Identification Wireless
Push and Crash Switch

[underlined] LODGE SYNTOX SCREENED SPARKING PLUG [/underlined]

[Page Break]

KLG White Corundum – CORUNDITE

Whereever [sic] there is a rolled Copper Washer fitted always replace when used once.

12 – 14 + 18 mm 3 standard sizes for plugs
U.S. plugs marked with red paint. Usual life. A.P 120 hrs every 4th inspection approx.

KLG – CORUNDITE – C [symbol]
Before this letter R means secured for radio.
Next type of plug. Next R means resistance in plug. i.e. RS5R = Large plus – screened for radio – type 5 – resistance incorporated.

[underlined] TORQUE LOADING [/underlined]

AC PLUGS – Red weight only
Lodge Plugs – Red – White – Blue
KLG Types RC12 & RC12/1 [symbol] Red White Blue & Yellow all other KLG use Red & White

Graphite & grease threads of plugs before inserting

2 signs for [deleted] [indecipherable words] [/deleted] high low tension leads.

[Page Break]

[deleted [calculation] [/deleted]

[underlined] Booster Coil [/underlined]


[Page Break]

[Blank Page]

[Page Break]

[Blank Page]

[Page Break]


[Page Break]

[inside back cover] [Engineering Brevet sketch]



A Gould, “Notebook,” IBCC Digital Archive, accessed June 23, 2024,

Item Relations

This item has no relations.