| Description | Date | Identifier | |
| Arrival of insulated segments for a Northcliffe & Williamson Ignition Switch. | 25th Jan 1915 | Box 31 \ 2 Scan011 | |
| To Mr Matthews regarding the urgent need to locate returned parts for a Northcliffe & Williamson Ignition Switch. | 26th Jan 1915 | Box 31 \ 2 Scan012 | |
| Instruction sheet detailing experiments incorporated on chassis 49 GB. | 1st Mar 1915 | Box 31 \ 2 Scan013 | |
| Note regarding an insulated switch fitted to the steering column of chassis 1920. | 11th Mar 1915 | Box 31 \ 2 Scan014 | |
| Letter discussing alternative schemes for charging ignition accumulators, referencing a suggestion from a Mr. Crampton. | 13th Apr 1915 | Box 31 \ 2 Scan015 | |
| Fault where an engine could be started by switching on the lights, and its resolution using a two-pole insulated switch. | 19th Feb 1920 | Box 31 \ 2 Scan016 | |
| Challenges and solutions for recharging ignition accumulators using the car's lighting battery. | 19th Feb 1920 | Box 31 \ 2 Scan017 | |
| Continued memo discussing a missed opportunity for cost savings related to accumulators. | 19th Feb 1920 | Box 31 \ 2 Scan018 | |
| Short internal memo confirming that an Insulating Switch has been fitted to chassis 49 GB. | 21th Apr 1915 | Box 31 \ 2 Scan019 | |
| Explaining the delay in producing an insulated ignition switch for a 6-volt coil due to outsourcing issues. | 22th Apr 1915 | Box 31 \ 2 Scan020 | |
| Complaint from Mr. Royce regarding a delay on the Ignition Switch for a 6 volt Coil, and a request for a report. | 22th Apr 1915 | Box 31 \ 2 Scan021 | |
| Inquiry regarding the delivery timeline for an insulated ignition switch for several cars, including 49GB. | 7th May 1915 | Box 31 \ 2 Scan022 | |
| Satisfactory road test of an ignition switch for a 6-volt coil, recommending further testing before standardisation. | 3rd Jun 1915 | Box 31 \ 2 Scan023 | |
| Report on an ignition switch for a 6 volt coil. | 27th Jul 1914 | Box 31 \ 2 Scan024 | |
| Proposing the standardization of an insulated battery switch fitted on the steering column. | 26th Apr 1917 | Box 31 \ 2 Scan025 | |
| The experimental fitting of an insulated ignition switch to a chassis. | 26th May 1915 | Box 31 \ 2 Scan026 | |
| Explaining the safety reasons and necessity for using an insulated ignition switch. | 8th Jul 1915 | Box 31 \ 2 Scan027 | |
| Internal query regarding the status of an ignition switch for a 6-volt coil. | 5th Aug 1915 | Box 31 \ 2 Scan028 | |
| And handwritten notes regarding a report on an experiment for an Ignition Switch for a 6 volt Coil. | 12th Aug 1915 | Box 31 \ 2 Scan029 | |
| Insulated ignition switch for a steering column, recommending its standardisation. | 12th Aug 1915 | Box 31 \ 2 Scan030 | |
| Short memo confirming that car 56NA, currently with Mr Royce, has been fitted with a particular system. | 19th Aug 1915 | Box 31 \ 2 Scan031 | |
| Three proposed changes for the ignition system, relating to the switch insulation, coil voltage, and a two-way battery switch. | 19th Aug 1915 | Box 31 \ 2 Scan032 | |
| Ignition Switch for a 6-volt coil, containing instructions to proceed with standardisation papers. | 24th Aug 1915 | Box 31 \ 2 Scan033 | |
| Seeking clarification on designing or procuring a new two-way ignition switch. | 17th Sep 1915 | Box 31 \ 2 Scan034 | |
| Standardisation of an ignition switch for a 6 volt coil. | 18th Sep 1915 | Box 31 \ 2 Scan035 | |
| Fitting an experimental insulated ignition switch to an engine. | 22th Apr 1910 | Box 31 \ 2 Scan036 | |
| Note specifying a three-cell battery, 6-volt lighting, and a six-volt Carpentier trembler coil for a car fitted with a Ryan dynamo. | 22th Apr 1910 | Box 31 \ 2 Scan037 | |
| Response to a memo from Mr. Royce, approving a 'Volt scheme'. | 29th Sep 1915 | Box 31 \ 2 Scan038 | |
| Standardisation of a 6-volt coil and insulated ignition switch for the steering column. | 7th Oct 1915 | Box 31 \ 2 Scan039 | |
| Use of a Lucas junction box and its electrical contact requirements. | 24th May 1919 | Box 31 \ 2 Scan040 | |
| Design of the vibrator regulator and relay current circuits. | 24th May 1919 | Box 31 \ 2 Scan041 | |
| Notice regarding an insulated switch on the steering column for the 7CA model. | 14th Aug 1919 | Box 31 \ 2 Scan042 | |
| To Mr. Coverley regarding a print for an insulated ignition switch. | 14th Aug 1919 | Box 31 \ 2 Scan043 | |
| List of new parts for a 40/50 chassis, detailing their standardization status and implementation agreement. | 1st Aug 1919 | Box 31 \ 2 Scan044 | |
| Alteration to the starter motor relay circuit and its switch, based on Mr. Royce's directive. | 4th Oct 1919 | Box 31 \ 2 Scan045 | |
| Instructions from Mr. Royce regarding the starter motor relay circuit and steering column switch. | 22th May 1919 | Box 31 \ 2 Scan046 | |
| Notification of alterations 1612/N and 1618/N to the 40/50 Chassis Wiring Diagram N.1293. | 1st Oct 1919 | Box 31 \ 2 Scan047 | |
| Danger of engine fire due to a sparking low-tension wire near a flooded carburettor. | 8th Mar 1920 | Box 31 \ 2 Scan048 | |
| Risk of sparks from a live battery ignition switch terminal and a proposed solution to insulate it. | 31th Dec 1920 | Box 31 \ 2 Scan049 | |
| Confirming instructions have been passed to the Buying Department regarding the battery ignition switch terminals insulating thimble. | 2nd Jun 1921 | Box 31 \ 2 Scan050 | |
| The fire danger of the steering column switch. | 20th Jul 1921 | Box 31 \ 2 Scan051 | |
| Letter from Rolls Royce of America Inc. concerning the fire danger of a steering column switch and suggesting alternative solutions. | 28th Jun 1921 | Box 31 \ 2 Scan052 | |
| The investigation of battery ignition switch terminals and insulating thimble. | 1st Aug 1921 | Box 31 \ 2 Scan053 | |
| Adaptation of a Goshawk Klaxon switch and control quadrant to the 40/50 chassis. | 29th Aug 1922 | Box 31 \ 2 Scan054 | |
| Design of an auxiliary ignition switch for the 40/50 model to work with the locked switch box. | 13th Jan 1923 | Box 31 \ 2 Scan055 | |
| Specification for a three-position ignition switch for the 40/50 and 20 HP models. | 13th Jan 1923 | Box 31 \ 2 Scan056 | |
| Dual ignition system for a Boshawk cylinder head, including the design of a three-position control switch. | 19th Jan 1923 | Box 31 \ 2 Scan057 | |
| Letter from the American branch to Derby explaining the reasons for using a single ignition switch. | 20th Feb 1923 | Box 31 \ 2 Scan058 | |
| Service issues with American Bosch magnetos and battery ignition systems, and proposing switch design improvements. | 8th Mar 1923 | Box 31 \ 2 Scan059 | |
| The adaptation of a Bijur lighting switch for use as an auxiliary ignition switch for the 7-GII model. | 8th Mar 1923 | Box 31 \ 2 Scan060 | |
| Request to instruct the Works to construct a crankshaft torsion model from wood, wire and staples. | 22th Aug 1914 | Box 31 \ 2 Scan061 | |
| The construction of a crankshaft torsional model. | 31th Aug 1914 | Box 31 \ 2 Scan062 | |
| Hand-drawn sketch of a wire crankshaft model intended for destructive testing. | 10th Sep 1914 | Box 31 \ 2 Scan063 | |
| Progress update on the Crankshaft Torsional Model. | 10th Sep 1914 | Box 31 \ 2 Scan064 | |
| Instruction sheet regarding a crankshaft torsional model. | 10th Sep 1914 | Box 31 \ 2 Scan065 | |
| Handover and despatch of the Crankshaft Torsion Model X.1418. | 10th Sep 1914 | Box 31 \ 2 Scan066 | |
| Instruction note for the despatch of a crankshaft torsion model to F.H. Royce. | 11th Sep 1914 | Box 31 \ 2 Scan067 | |
| Production and dispatch of a crankshaft torsion model. | 10th Sep 1914 | Box 31 \ 2 Scan068 | |
| Results of crankshaft torsion tests on a 20 HP shaft, from its initial forging to the finished state. | 12th Dec 1927 | Box 31 \ 2 Scan069 | |
| Page discussing discrepancies in crankshaft stiffness calculations and the reinforcing effect of bearings. | 12th Dec 1927 | Box 31 \ 2 Scan070 | |
| Tests on crankshaft stiffness, deflection, and 'bell-mouthing' for various engine models. | 9th Dec 1927 | Box 31 \ 2 Scan071 | |
| Graph showing the deflection of a central journal when twisting a 20 HP crankshaft. | 9th Dec 1927 | Box 31 \ 2 Scan072 | |
| The reverse side of a document featuring a purple ink date stamp from the Derby office. | 10th Dec 1927 | Box 31 \ 2 Scan073 | |
| Graph of crankshaft torsion tests comparing torque vs. twist for various Phantom & 20 HP crankshaft configurations. | 7th Dec 1927 | Box 31 \ 2 Scan074 | |
| Table of torsion test results for a 20 HP crankshaft from forging to finished shaft. | 7th Dec 1927 | Box 31 \ 2 Scan075 | |
| Graph showing the results of a 20 HP crankshaft torsion test, tracking changes from forging to the finished shaft. | 6th Dec 1927 | Box 31 \ 2 Scan076 | |
| Blank, folded document page with a purple 'Print Room' date stamp. | 10th Dec 1927 | Box 31 \ 2 Scan077 | |
| Responses from the Chief Engineers of Sunbeam and Vauxhall to an article about the 'Battle of the Valves'. | 1st Aug 1914 | Box 31 \ 2 Scan078 | |
| Paper on poppet valve design, discussing seat widths, side thrust, and the effects of carbon on valve seatings. | 31th Oct 1914 | Box 31 \ 2 Scan079 | |
| Article discussing side pressure on valve stems and poppet valve design. | 31th Oct 1914 | Box 31 \ 2 Scan080 | |
| Forwarding a circular about the 'Apex' Priming & Compression Valve from W. Edward Storey. | 12th Oct 1920 | Box 31 \ 2 Scan081 | |
| Arranging an interview with the patentee's representative for a Micrometer Valve Adjustment Device. | 7th May 1923 | Box 31 \ 2 Scan082 | |
| From Hs. to CMS regarding a proposed visit to Derby by Mr. Watson. | 23th May 1923 | Box 31 \ 2 Scan083 | |
| Properties and use of aluminium bronze for inserted valve seats, quoting the S.A.E. journal. | 27th Sep 1926 | Box 31 \ 2 Scan084 | |
| Follow-up request for test results and an opinion on valve springs from the Anglo American Steel Company. | 19th Oct 1926 | Box 31 \ 2 Scan085 | |
| Composition of 'Ochromite' valves and a proposal to order a set for the Condor engine. | 9th Jun 1927 | Box 31 \ 2 Scan086 | |
| Request to manufacture dummy valves in aluminium for testing valve shapes for efficient induction. | 19th Oct 1928 | Box 31 \ 2 Scan087 | |
| Variations in the Brinell hardness of aluminium bronze valve seatings and proposing tests on a harder material. | 18th Jul 1929 | Box 31 \ 2 Scan088 | |
| Cause of noisy valve gear due to manufacturing inaccuracies of the cam toe. | 27th Mar 1933 | Box 31 \ 2 Scan089 | |
| Engine improvements by increasing inlet valve area and cylinder count for greater power output. | 18th May 1933 | Box 31 \ 2 Scan090 | |
| Engine valve particulars and their effect on performance across different models. | 18th May 1933 | Box 31 \ 2 Scan091 | |
| Comparison table of performance metrics for various engine cylinder configurations. | 14th Jul 1933 | Box 31 \ 2 Scan092 | |
| Instructions for modifying Phantom II cylinder head sections for experimental airflow work. | 14th Jul 1933 | Box 31 \ 2 Scan093 | |
| Requesting a wooden model of an improved inlet valve port for a Bentley engine to be made for testing on a blower rig. | 17th Jul 1933 | Box 31 \ 2 Scan094 | |
| Requesting the replacement of old valves with the latest type on a Phantom II cylinder head. | 20th Jul 1933 | Box 31 \ 2 Scan095 | |
| Unsuccessful larger inlet valves for an 8 Litre Phantom due to being too heavy, requesting modification. | 21th Jul 1933 | Box 31 \ 2 Scan096 | |
| Requesting an 8 litre and a 4 litre Bentley cylinder head for testing the orifice coefficient of valve ports. | 22th Jul 1933 | Box 31 \ 2 Scan097 | |
| Request for valve springs and cotters to complete tests on a borrowed Bentley 8 Litre cylinder block. | 27th Jul 1933 | Box 31 \ 2 Scan098 | |
| Tests comparing the efficiency of valving on Phantom II and Bentley engines. | 24th Aug 1933 | Box 31 \ 2 Scan099 | |
| Tests for compression pressure, volumetric efficiency, and air flow across various cylinder head and valve configurations. | 24th Aug 1933 | Box 31 \ 2 Scan100 | |
| Summary of various air flow and pressure difference tests for different engine cylinder heads and valves. | 24th Aug 1933 | Box 31 \ 2 Scan101 | |
| List of air flow and pressure difference tests on various valve and cylinder head configurations. | 24th Aug 1933 | Box 31 \ 2 Scan102 | |
| Deductions from tests on the Phantom engine, focusing on valve lift, efficiency, and size. | 24th Aug 1933 | Box 31 \ 2 Scan103 | |
| Analysis of engine port shape and design, comparing 8-litre Phantom and Bentley cylinder heads. | 24th Aug 1933 | Box 31 \ 2 Scan104 | |
| Airflow tests conducted on experimental wooden models of engine heads with different port and valve designs. | 24th Aug 1933 | Box 31 \ 2 Scan105 | |
| Analysis comparing engine performance based on port design, air flow, and valve size for Phantom and Bentley heads. | 24th Aug 1933 | Box 31 \ 2 Scan106 | |
| Potential engine performance improvements for Rolls-Bentley and Phantom models by modifying head design and camshafts. | 24th Aug 1933 | Box 31 \ 2 Scan107 | |
| Diagrams illustrating the method of shrouding a valve for air flow tests and modifications to an inlet valve. | 24th Aug 1933 | Box 31 \ 2 Scan108 | |
| Diagrammatic arrangement of a rig used in cylinder head air flow tests. | 24th Aug 1933 | Box 31 \ 2 Scan109 | |
| Blueprint diagram showing a cross-section of a modified inlet valve. | 24th Aug 1933 | Box 31 \ 2 Scan110 | |
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