| Description | Date | Identifier | |
| Spark plug failures due to overheating and carbon, and the testing of various plug types. | 8th May 1918 | Box 34 \ 2 Scan097 | |
| Ideal spark plug insulator materials and designs to resist carbon build-up. | 8th May 1918 | Box 34 \ 2 Scan098 | |
| The performance of modified ignition plugs designed for easier cleaning. | 14th May 1918 | Box 34 \ 2 Scan099 | |
| Letter to the Air Board Technical Dept. discussing the advantages of using jump spark distributors for the 'Condor' engine ignition. | 14th May 1918 | Box 34 \ 2 Scan100 | |
| Ignition plug failures from sooty deposits and the potential of a jump spark distributor. | 14th May 1918 | Box 34 \ 2 Scan101 | |
| Experiments into pre-ignition and ignition, focusing on the overheating effects of different spark plug designs. | 15th May 1918 | Box 34 \ 2 Scan102 | |
| Analysis of engine overheating causes related to ignition, spark plug gaps, plug temperature, and compression ratios. | 5th May 1918 | Box 34 \ 2 Scan103 | |
| Engine tests on pre-ignition, overheating, and detonation, noting the effect of charge temperature. | 15th May 1918 | Box 34 \ 2 Scan104 | |
| Investigation into engine pre-ignition and the effect of warming up the fuel-air charge. | 15th May 1918 | Box 34 \ 2 Scan105 | |
| Analysis of engine 'running on' after being switched off, exploring causes like spontaneous combustion and temperature. | 15th May 1918 | Box 34 \ 2 Scan106 | |
| Comparison of magneto versus battery ignition systems, noting performance differences under various conditions. | 15th May 1918 | Box 34 \ 2 Scan107 | |
| Sparking plug tests with manufacturers Lodge and K.L.G., and proposing the testing scheme to the Air Board. | 30th May 1918 | Box 34 \ 2 Scan108 | |
| Continued document discussing issues with porcelain cracking under excessive heat, particularly with special plugs from 'Lodge'. | 30th May 1918 | Box 34 \ 2 Scan109 | |
| From E.H. to C.J. dismissing a suggestion for sparking plugs as impracticable. | 30th May 1918 | Box 34 \ 2 Scan110 | |
| CJ to EH regarding a request from Mr. Thos. W. Hall. | 28th May 1918 | Box 34 \ 2 Scan111 | |
| Letter suggesting the use of a fusible alloy instead of mercury for cooling aeroplane engine spark plugs. | 25th May 1918 | Box 34 \ 2 Scan112 | |
| Letter from a draughtsman proposing a plug modification using fused metal instead of mercury. | 18th Jan 1919 | Box 34 \ 2 Scan113 | |
| Proposal to modify aero engine spark plugs with a fusible alloy plug. | 18th Jan 1919 | Box 34 \ 2 Scan114 | |
| Letter politely declining a suggestion due to being fully occupied with war work. | 1st Jun 1918 | Box 34 \ 2 Scan115 | |
| Telegram concerning the testing of new plugs designed to withstand overoiling and heat conditions. | 5th Jun 1917 | Box 34 \ 2 Scan116 | |
| Urgent need to supply a temporary type of sparking plug to customers. | 29th Mar 1919 | Box 34 \ 2 Scan117 | |
| Test results for various spark plugs under compression pressure after an engine run. | 29th Mar 1919 | Box 34 \ 2 Scan118 | |
| Issues with sparking plugs, pre-ignition and misfires on the 300 HP Eagle 'B' engine. | 6th Sep 1916 | Box 34 \ 3 Scan001 | |
| Extract concerning sourcing insulators to manufacture sparking plugs for the 'Eagle' 'B' engine. | 15th Sep 1916 | Box 34 \ 3 Scan002 | |
| 24-hour test of a new sparking plug design for the 'Eagle' 'B' engine, comparing it to a Bosch model. | 8th Sep 1916 | Box 34 \ 3 Scan003 | |
| List of Bosch magnetos and spark plugs with their associated reference numbers. | 1st Mar 1918 | Box 34 \ 3 Scan004 | |
| Test results of various spark plugs under compression pressure at different magneto speeds. | 1st Mar 1918 | Box 34 \ 3 Scan005 | |
| Tests on different types of sparking plugs due to misfiring issues, concluding K.L.G. plugs are unreliable. | 23th Oct 1919 | Box 34 \ 3 Scan006 | |
| Performance of Lodge make ignition plugs with mica insulation compared to older K.L.G. and porcelain plug types. | 10th Sep 1920 | Box 34 \ 3 Scan007 | |
| Difficulty of cleaning certain spark plugs and comparing them to detachable alternatives. | 10th Sep 1920 | Box 34 \ 3 Scan008 | |
| Engine performance issues, specifically soot deposits, ignition problems at slow speeds, and potential valve clearance issues. | 10th Sep 1920 | Box 34 \ 3 Scan009 | |
| Chassis 39-TW, discussing improvements to ignition plugs and condensers. | 12th Nov 1920 | Box 34 \ 3 Scan010 | |
| Selection, ordering, and testing of various brands of sparking plugs. | 2nd Feb 1921 | Box 34 \ 3 Scan011 | |
| Proposal to reduce costs and save time by repairing Mercury plugs. | 1st Aug 1921 | Box 34 \ 3 Scan012 | |
| Performance of Champion and Mercury ignition plugs and suggesting design improvements. | 12th Apr 1921 | Box 34 \ 3 Scan013 | |
| Continued discussion on material properties, comparing ordinary steel to yellow brass. | 12th Apr 1921 | Box 34 \ 3 Scan014 | |
| Modifications to car starting equipment for 6 volts, including the winding, magnetic switch, and brass button. | 3rd Oct 1916 | Box 34 \ 3 Scan015 | |
| Post-war chassis components, focusing on the self-starter motor, ignition switch, and a detailed analysis of road wheel design, materials, and testing. | 3rd Oct 1916 | Box 34 \ 3 Scan016 | |
| Overhaul and proposed improvements for a car engine. | 19th Apr 1917 | Box 34 \ 3 Scan017 | |
| List of specifications for various vehicle components, including brake straps, gears, springs, and wheels. | 18th Apr 1917 | Box 34 \ 3 Scan018 | |
| Requirements and modifications for Car 7 C.A. concerning suspension, engine, and other components. | 11th May 1917 | Box 34 \ 3 Scan019 | |
| Car modifications covering the starter, back axle, induction pipe, and gear ratios for improved road holding and petrol economy. | 11th May 1917 | Box 34 \ 3 Scan020 | |
| Fitting of an experimental new push button starter switch to the RE 7 C.A. CAR. | 1st Jun 1917 | Box 34 \ 3 Scan021 | |
| Extract listing experimental parts for car '5 C.A.' as delivered to Mr. Royce, highlighting a new push button switch. | 15th Jun 1917 | Box 34 \ 3 Scan022 | |
| Foot-operated push-button starter switch for the post-war chassis, considering design improvements. | 10th Sep 1917 | Box 34 \ 3 Scan023 | |
| Placement of the starter and main switches for the After-the-War-Chassis-X. | 2nd May 1919 | Box 34 \ 3 Scan024 | |
| Mr. Royce's decision to change the starter push button to be foot-operated on the dashboard. | 2nd May 1919 | Box 34 \ 3 Scan025 | |
| Description of the motor starting system, including its electrical operation and gear reduction ratios. | 26th May 1919 | Box 34 \ 3 Scan026 | |
| Design change to Aluminium Die Castings for a push-button switch due to high scrap rates. | 30th May 1919 | Box 34 \ 3 Scan027 | |
| Assembly completion report for Chassis 1. E.X., listing the parts and corresponding Engineering Schedule numbers. | 30th Jun 1919 | Box 34 \ 3 Scan028 | |
| Safety feature for the electric starter to prevent operation unless the vehicle is in neutral. | 23th Jul 1919 | Box 34 \ 3 Scan029 | |
| Specification table for a push button switch showing various gap measurements and button depression values. | 2nd Aug 1919 | Box 34 \ 3 Scan030 | |
| Production faults with push button switches. | 20th Aug 1919 | Box 34 \ 3 Scan031 | |
| Table of measurements and test remarks for production push button switches. | 22th Aug 1919 | Box 34 \ 3 Scan032 | |
| Table of measurements for production push button switches, numbers 11 through 20. | 22th Aug 1919 | Box 34 \ 3 Scan033 | |
| The production testing procedures for push button switches. | 26th Aug 1919 | Box 34 \ 3 Scan034 | |
| Measurement procedures and tolerances for push-button switches. | 26th Aug 1919 | Box 34 \ 3 Scan035 | |
| Specification sheet detailing the gap and depression measurements for a push-button switch. | 2nd Aug 1919 | Box 34 \ 3 Scan036 | |
| Table of clearances for a push button switch. | 23th Aug 1919 | Box 34 \ 3 Scan037 | |
| Clarifying departmental responsibility for certifying experimental push button switches for starter gears. | 27th Aug 1919 | Box 34 \ 3 Scan038 | |
| Diagram of a push-button switch showing movement radii and a method for testing carbon gap clearance. | 27th Aug 1919 | Box 34 \ 3 Scan039 | |
| Instructions for setting and measuring the gaps on a push button switch. | 27th Aug 1919 | Box 34 \ 3 Scan040 | |
| List of new parts fitted to the 40/50 chassis, comparing them with the pre-War 40/50 HP chassis. | 27th Aug 1919 | Box 34 \ 3 Scan041 | |
| Transferring the testing of push button and main switches from the Experimental to the Electrical Production Department. | 4th Sep 1919 | Box 34 \ 3 Scan042 | |
| Notification regarding a push button switch developing an earth due to an unsuitable insulating button. | 11th Sep 1919 | Box 34 \ 3 Scan043 | |
| Push-button switch failure due to earthing, with a proposed design modification. | 10th Sep 1919 | Box 34 \ 3 Scan044 | |
| Page detailing modifications to a P.B. Switch regarding spigots, bosses, and covers. | 10th Sep 1919 | Box 34 \ 3 Scan045 | |
| Alteration of a push-button switch, including a technical sketch with dimensions. | 18th Sep 1919 | Box 34 \ 3 Scan046 | |
| The measurements and tolerances for a push-button switch. | 23th Sep 1919 | Box 34 \ 3 Scan047 | |
| Complaints with the engine starter clutch mechanism and suggestions for a remedy. | 28th Nov 1919 | Box 34 \ 3 Scan048 | |
| Issues and proposed alterations for the chassis engine starter mechanism. | 1st Dec 1919 | Box 34 \ 3 Scan049 | |
| The operation of an actuator box, push-button switch, and actuator coils. | 11th Dec 1919 | Box 34 \ 3 Scan050 | |
| Request for Mr. Brock to supply one Push Button Switch to EFC, noting it needs replacing. | 1st Dec 1919 | Box 34 \ 3 Scan051 | |
| Request for a push button switch from production for experimental testing on time lag. | 12th Dec 1919 | Box 34 \ 3 Scan052 | |
| Extract detailing modifications for a re-wiring scheme on a standard chassis. | 8th Dec 1919 | Box 34 \ 3 Scan053 | |
| Short memo to Mr. Clark regarding a borrowed push button switch. | 11th Dec 1919 | Box 34 \ 3 Scan054 | |
| Test report on the lag in action of an actuator box and switch, detailing electrical resistance, current, and load measurements. | 15th Dec 1919 | Box 34 \ 3 Scan055 | |
| Test results and specifications for an actuator box with two coils. | 16th Jun 1939 | Box 34 \ 3 Scan056 | |
| Heating test report for actuator coils with results for various timings and conditions. | 16th Apr 1939 | Box 34 \ 3 Scan057 | |
| Conclusion of actuator load tests, detailing maximum loads and current draw for different models. | 13th Apr 1920 | Box 34 \ 3 Scan058 | |
| Complaint regarding failures and insufficient clearance on the dashboard starter switch due to 'earthing'. | 13th Apr 1920 | Box 34 \ 3 Scan059 | |
| Design and potential faults of a push-button switch. | 15th Apr 1920 | Box 34 \ 3 Scan060 | |
| Fault with a push button switch causing it to short. | 21th Apr 1920 | Box 34 \ 3 Scan061 | |
| Providing instructions for the production adjustment and testing of a main switch and a push-button switch. | 8th May 1920 | Box 34 \ 3 Scan062 | |
| Failures and danger from shorting caused by the starter switch cover. | 29th May 1920 | Box 34 \ 3 Scan063 | |
| Proposed modification to insulate the arm of a push-button switch to prevent short circuits. | 1st Jun 1920 | Box 34 \ 3 Scan064 | |
| Safer insulation for the press button starter switch using a thimble. | 3rd Jun 1920 | Box 34 \ 3 Scan065 | |
| Complaint and proposed solution for insulating a press button starter switch to prevent an electrical earth. | 8th Jun 1920 | Box 34 \ 3 Scan066 | |
| Potential failure of thread in ebonite for a press button starter switch. | 9th Jun 1920 | Box 34 \ 3 Scan067 | |
| New chassis troubles for Chassis 46-LW, detailing an earthing fault and issues with the fusing system. | 26th Jul 1920 | Box 34 \ 3 Scan068 | |
| Letter from M. Olley of the American branch concerning electrical faults and recommendations. | 26th Jul 1920 | Box 34 \ 3 Scan069 | |
| Extract detailing electrical equipment troubles experienced with imported chassis. | 19th Aug 1920 | Box 34 \ 3 Scan070 | |
| Ongoing trouble with the earthing of a press button starter switch and the need for better insulation. | 20th Dec 1920 | Box 34 \ 3 Scan071 | |
| Potential improvements and standardization for 'R' series materials and components. | 11th Feb 1921 | Box 34 \ 3 Scan072 | |
| Ongoing earthing issues with chassis starter switches and proposed solutions. | 3rd Mar 1921 | Box 34 \ 3 Scan073 | |
| Making parts in Bakelite, suggesting a push button switch as an experimental piece. | 10th May 1921 | Box 34 \ 3 Scan074 | |
| Letter from Rolls-Royce of America regarding a misfiring Watford magneto due to bushing wear and a proposal for using Bakelised linen as a replacement material. | 13th May 1921 | Box 34 \ 3 Scan075 | |
| The experimental use of Bakelite mouldings for a part. | 31th May 1921 | Box 34 \ 3 Scan076 | |
| Modifications to the Goshawk 11 Klaxon switch and controls on the steering column. | 14th Jun 1921 | Box 34 \ 3 Scan077 | |
| Letter to the Managing Director suggesting improvements to electrical insulation materials to improve heat resistance and reduce costs. | 24th Mar 1921 | Box 34 \ 3 Scan078 | |
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