| Description | Date | Identifier | |
| Stronger actuator box for parallel arrangement and related starter clutch modifications. | 16th Jan 1920 | Box 75 \ 1 scan0097 | |
| Table of gear ratios and speeds for a 40/50 HP chassis with a four-speed gearbox for various wheel sizes. | 6th Aug 1919 | Box 75 \ 1 scan0098 | |
| Data sheet showing gear ratios and speeds for a 40/50 HP chassis with a four-speed gearbox. | 6th Jun 1919 | Box 75 \ 1 scan0099 | |
| Table of gear ratios and speeds for a 40/50 HP chassis with a four-speed gearbox. | 16th Jan 1920 | Box 75 \ 1 scan0100 | |
| Recommendation to adopt a stronger actuator box and implement necessary modifications for the starter clutch. | 16th Jan 1920 | Box 75 \ 1 scan0101 | |
| Recurring fault with the starter clutch mechanism and requesting additional pre-assembly inspections. | 19th Jan 1920 | Box 75 \ 1 scan0102 | |
| The failure of the actuating box for the engine starter and investigating a jaw clutch issue. | 19th Jan 1920 | Box 75 \ 1 scan0103 | |
| Cover memo for a standardisation sheet concerning a jaw clutch engaging starter motor and bush. | 20th Jan 1920 | Box 75 \ 1 scan0104 | |
| Covering memo for a standardisation sheet regarding a jaw clutch engaging starter motor and bush. | 23th Jan 1920 | Box 75 \ 1 scan0105 | |
| Directive on the standardization of a jaw clutch for the starter motor and bush, pending a 10,000-mile test run. | 27th Jan 1920 | Box 75 \ 1 scan0106 | |
| Fault with the jaw clutch engaging starter motor and bush, preventing delivery of faulty cars. | 27th Jan 1920 | Box 75 \ 1 scan0107 | |
| Manufacture of a modified jaw clutch for a starter motor, pending a 10,000-mile trial. | 30th Jan 1920 | Box 75 \ 1 scan0108 | |
| Modification to the Jaw Clutch for the Starter on a 40/50 Chassis. | 1st Jan 1920 | Box 75 \ 1 scan0109 | |
| Modification to a jaw clutch, specifically the design of the bush face to avoid sticking and bruising. | 1st Jan 1920 | Box 75 \ 1 scan0110 | |
| Extract detailing a list of items to be fitted to a chassis for American trials. | 4th Feb 1920 | Box 75 \ 1 scan0111 | |
| The completed standardisation sheets for a jaw clutch engaging starter motor and bush. | 16th Feb 1920 | Box 75 \ 1 scan0112 | |
| Standardisation document for the jaw clutch engaging starter motor and bush. | 20th Jan 1920 | Box 75 \ 1 scan0113 | |
| Hand-drawn cross-section of a component with annotations. | 21th Jan 1920 | Box 75 \ 1 scan0114 | |
| Issues with a faulty starter mechanism and proposed modifications. | 21th Jan 1920 | Box 75 \ 1 scan0115 | |
| Instructions for modifying bushes, jaw clutches, starter clutches, and halting gear box assembly pending corrections. | 2nd Feb 1920 | Box 75 \ 1 scan0116 | |
| Approval and standardisation of a proposed modification to the jaw clutch on the self-starter. | 2nd Feb 1920 | Box 75 \ 1 scan0117 | |
| Proposed modification to the Jaw Clutch on the Self Starter. | 4th Feb 1920 | Box 75 \ 1 scan0118 | |
| Failure of an engine starter drive and the faulty adjustment of the slipper mechanism. | 25th Feb 1920 | Box 75 \ 1 scan0119 | |
| Complaint regarding a hand starter failure caused by fibre swelling, with a recommendation to use bronze instead. | 28th Feb 1920 | Box 75 \ 1 scan0120 | |
| Failure of an engine starter drive and the substitution of bronze plates with grey fibre. | 1st Mar 1920 | Box 75 \ 1 scan0121 | |
| The failure of the engine starter drive and concerns over its reliability. | 5th Mar 1920 | Box 75 \ 1 scan0122 | |
| Ratios and speeds of 40/50 HP. chassis with a four-speed gearbox for various axle gears and wheel sizes. | 22th Mar 1920 | Box 75 \ 1 scan0123 | |
| Confirming the completion status of three experiments: a jaw clutch modification, cable encasing, and a main switch base plate. | 25th Mar 1920 | Box 75 \ 1 scan0124 | |
| Extract discussing urgent design features and production delays. | 26th Mar 1920 | Box 75 \ 1 scan0125 | |
| Design alterations and delays in output due to various vehicle faults. | 26th Mar 1920 | Box 75 \ 1 scan0126 | |
| Issues with engine starter slipper drives and the need for instructions for modification. | 15th Apr 1920 | Box 75 \ 1 scan0127 | |
| Modifications by the Experimental Department to the self-starter gear and springs on the gearbox. | 20th Apr 1920 | Box 75 \ 1 scan0128 | |
| Unsatisfactory engine starter slipper drives, arranging for temporary fixes and requesting instructions for a permanent solution. | 15th Apr 1920 | Box 75 \ 1 scan0129 | |
| Request for a drawing showing modifications to the friction drive for the self-starter gear to prevent slipping. | 20th Apr 1920 | Box 75 \ 1 scan0130 | |
| EFC to Hs requesting feedback on specific electrical parts for chassis 7.CA. | 27th Apr 1920 | Box 75 \ 1 scan0131 | |
| Proposal for modifying faulty starter mechanisms on cars that have already been delivered. | 28th Apr 1920 | Box 75 \ 1 scan0132 | |
| Typed list of clients, trials, and locations with corresponding reference codes. | 8th May 1920 | Box 75 \ 1 scan0133 | |
| Fault with the starter gear on the gearbox due to a weak friction plate, with a proposed solution. | 8th May 1920 | Box 75 \ 1 scan0134 | |
| Instruction regarding a retrospective modification to make the engine starter slipper drive solid. | 7th May 1920 | Box 75 \ 1 scan0135 | |
| Modification and rectification of faulty chassis self-starter clutches on previously delivered cars. | 14th May 1920 | Box 75 \ 1 scan0136 | |
| Requesting a standardisation sheet for a 3-speed gearbox to allow for a document attachment. | 21th Sep 1920 | Box 75 \ 1 scan0137 | |
| Comparing gear ratios of a failed 3-speed car with successful 4-speed cars to argue against a new 3-speed gearbox design. | 9th Sep 1920 | Box 75 \ 1 scan0138 | |
| Comparison of gear ratios and a discussion on hill-climbing performance for various cars. | 9th Sep 1920 | Box 75 \ 1 scan0139 | |
| Concerns about a new 3-speed gearbox and the increasing weight of cars. | 9th Sep 1920 | Box 75 \ 1 scan0140 | |
| The necessity of a three or four-speed gearbox for heavy luxury cars. | 12th Oct 1920 | Box 75 \ 1 scan0141 | |
| Back axle gear ratios in relation to car weight for equal hill climbing and acceleration. | 12th Oct 1920 | Box 75 \ 1 scan0142 | |
| Expected improvements in new car designs, including gear ratios, power, and the justification for a three-speed gearbox. | 12th Oct 1920 | Box 75 \ 1 scan0143 | |
| Arguing for a three-speed gearbox over a four-speed one, citing complexity and overall perfection. | 12th Oct 1920 | Box 75 \ 1 scan0144 | |
| Merits of a semi-epicyclic four-speed gearbox versus a three-speed design. | 12th Oct 1920 | Box 75 \ 1 scan0145 | |
| Merits of a three-speed gearbox with a lower top gear versus a four-speed for better acceleration in traffic. | 22th Oct 1920 | Box 75 \ 1 scan0146 | |
| Engine speed, gearing for different car types, and personal driving preferences. | 22th Oct 1920 | Box 75 \ 1 scan0147 | |
| Advantages of a new 3-speed gearbox and reconsidering steering and gear change configurations for different markets. | 30th Mar 1921 | Box 75 \ 1 scan0148 | |
| Single-page document posing a question about potential use in the U.S.A. | 21th Jun 1921 | Box 75 \ 1 scan0149 | |
| Drive train chunking, slack, and other issues in Derby and Springfield cars. | 21th Jun 1921 | Box 75 \ 1 scan0150 | |
| Production issue with bearings being too tight a fit in their housing. | 1st Jul 1921 | Box 75 \ 1 scan0151 | |
| The completion of the Goshawk 11 engine unit and the plan to discuss it with Mr. Royce at West Wittering. | 1st Jul 1921 | Box 75 \ 1 scan0152 | |
| Tests for a starter motor on a 40/50 car with a 3-speed gearbox to achieve a more silent engagement. | 1st Aug 1921 | Box 75 \ 1 scan0153 | |
| Tests on a starter motor for a car with a 3-speed gear box. | 11th Aug 1920 | Box 75 \ 1 scan0154 | |
| Comparative test results for a motor, with/without an epicyclic gear and with varying numbers of brushes. | 11th Aug 1920 | Box 75 \ 1 scan0155 | |
| Gearbox noises, suggesting the cause is either incorrectly made gear teeth or a decline in the quality of ball bearings. | 31th Aug 1921 | Box 75 \ 1 scan0156 | |
| Testing and performance of a gearbox fitted with new ground gears. | 3rd Nov 1921 | Box 75 \ 1 scan0157 | |
| Query regarding a standardisation sheet for the use of ground gears in 40/50 gearboxes. | 16th Jan 1922 | Box 75 \ 1 scan0158 | |
| Investigation into two systems of gear grinding, the Maag system and the Gear Grinding Co. system. | 1st Feb 1922 | Box 75 \ 1 scan0159 | |
| Comparison between an American machine and a later type developed by the Gear Grinding Co. | 21th Feb 1922 | Box 75 \ 1 scan0160 | |
| Standardisation of ground gears for the gearbox to improve silence. | 23th Jan 1922 | Box 75 \ 1 scan0161 | |
| Letter from the Springfield, Mass. office requesting the layout print for a Three-Speed Gear Box. | 18th Apr 1922 | Box 75 \ 1 scan0162 | |
| Compression ratios and axle gear ratios for the 40/50 model. | 25th Jul 1922 | Box 75 \ 1 scan0163 | |
| Engine characteristics, refinement, and the importance of weight reduction in vehicle design. | 15th Aug 1922 | Box 75 \ 1 scan0164 | |
| Investigation and potential solutions for a rattle from the gearbox. | 15th Aug 1922 | Box 75 \ 1 scan0165 | |
| Communication discussing an experiment to fix a brake on a side shaft, comparing it to a magneto drive. | 15th Aug 1922 | Box 75 \ 1 scan0166 | |
| Rattles from the gearbox side shaft and potential solutions. | 25th Aug 1922 | Box 75 \ 1 scan0167 | |
| Suggestion to use ground gears for the side shaft of the 40/50 gearbox to overcome a rattling complaint. | 9th Sep 1922 | Box 75 \ 1 scan0168 | |
| Adoption of a filler plug and oil level gauge for gearboxes on the 40/50 car. | 12th Jan 1923 | Box 75 \ 1 scan0169 | |
| Investigation into a groaning noise from the 40/50 gearbox when starting from a standstill. | 18th Jan 1923 | Box 75 \ 1 scan0170 | |
| Fit of gears on keys for a 40/50 gearbox and proposed solutions. | 24th Jan 1923 | Box 75 \ 1 scan0171 | |
| Proposed modifications to the 40/50 HP gearbox for easier oil level checking and filling. | 24th May 1923 | Box 75 \ 1 scan0172 | |
| Standardisation of an oil filler plug for the gear box. | 28th Jun 1923 | Box 75 \ 1 scan0173 | |
| Proposal for a plug in the end of a change gear tube, forwarding a letter from Springfield. | 28th Aug 1923 | Box 75 \ 1 scan0174 | |
| Letter regarding a proposal to fit a plug in the end of the change gear tube to address oil dripping. | 15th Aug 1925 | Box 75 \ 1 scan0175 | |
| The despatch of 40/50 HP chassis gear box blanks for machining and subsequent testing. | 29th Aug 1923 | Box 75 \ 1 scan0176 | |
| Standardisation of adjusting washers on the selector lock in the gearbox. | 24th Sep 1923 | Box 75 \ 1 scan0177 | |
| Testing of ground bevel gears on different axles to assess their quietness. | 30th Oct 1923 | Box 75 \ 1 scan0178 | |
| Request to fit a shorter change speed lever to a 40/50 HP chassis. | 29th Nov 1923 | Box 75 \ 1 scan0179 | |
| Requesting the return of a short change speed lever for a 40/50 HP Chassis. | 4th Dec 1923 | Box 75 \ 1 scan0180 | |
| The back axle and chassis gear ratios for the Goshawk II model. | 8th Dec 1923 | Box 75 \ 1 scan0181 | |
| Standardisation of a distance piece in gearbox G.2145 to reduce cost by omitting unnecessary serrations. | 7th Dec 1923 | Box 75 \ 1 scan0182 | |
| Draught issue from the 40/50 HP gearbox causing the driver's leg to freeze. | 21th Mar 1924 | Box 75 \ 1 scan0183 | |
| Implementation of a shorter gear lever and the performance of the 20 HP foot brake. | 3rd Jun 1924 | Box 75 \ 1 scan0184 | |
| 'India' gearbox test, detailing an issue with the gear lever working out of 1st and 2nd gear. | 28th Feb 1925 | Box 75 \ 1 scan0185 | |
| Secret memo regarding gearbox issues on the 'V' series underframe chassis and the provision of a new torsionally free pinion. | 3rd Mar 1925 | Box 75 \ 1 scan0186 | |
| Secret internal memo regarding instructions for shaft splines on 40/50 and India gearboxes. | 22th Apr 1925 | Box 75 \ 1 scan0187 | |
| Secret memo regarding spline design for the 40/50 & India Gearbox pinions, with input from Mr. Royce. | 24th Apr 1925 | Box 75 \ 1 scan0188 | |
| Letter to Mr. Claremont discussing the proposal of a freewheel mechanism with a positive clutch to improve acceleration. | 24th Oct 1928 | Box 75 \ 1 scan0189 | |
| Technical discussion on an alternative gearbox design using an epicyclic unit. | 24th Oct 1928 | Box 75 \ 1 scan0190 | |
| Letter from F.H. Royce discussing the design and benefits of epicyclic gear arrangements. | 31th Jan 1919 | Box 75 \ 1 scan0191 | |
| The drawing and forging details for a three-speed gearbox for a small chassis. | 31th Jan 1919 | Box 75 \ 1 scan0192 | |
| Transmittal slip for a print of an Experimental 3-Speed Gear Box for a Small Chassis. | 5th Feb 1919 | Box 75 \ 1 scan0193 | |
| Arguing in favour of a 4-speed gearbox over a 3-speed gearbox. | 12th Feb 1929 | Box 75 \ 1 scan0194 | |
| The merits of a 4-speed gearbox over a 3-speed, considering performance, economy, and suitability for different cars. | 12th Feb 1919 | Box 75 \ 1 scan0195 | |
| Continued note regarding improving consumption. | 12th Feb 1919 | Box 75 \ 1 scan0196 | |
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