| Description | Date | Identifier | |
| Mr. Royce's remarks on various 40/50 HP chassis piston designs. | 25th Feb 1919 | Box 181 \ M11 img144 | |
| Compression ratios for post-war 40/50 HP chassis cars. | 25th Feb 1919 | Box 181 \ M11 img145 | |
| Mr. Royce's requested design changes for a 40/50 HP chassis die-cast piston. | 6th Mar 1919 | Box 181 \ M11 img146 | |
| Design modifications for pistons, specifically concerning internal webs and piston ring pin spacing. | 11th Mar 1919 | Box 181 \ M11 img147 | |
| Improving gear changes, dismissing a cycle change gear idea and considering a free-wheel arrangement. | 11th Mar 1919 | Box 181 \ M11 img148 | |
| Modifications to a gear-changing mechanism, including the addition of a positive jaw clutch to a free wheel system. | 1st Jun 1930 | Box 181 \ M11 img149 | |
| Electrically operated gear changing mechanism using a jaw and friction clutch. | 11th Mar 1919 | Box 181 \ M11 img150 | |
| Letter discussing a proposed carburettor design, an alternative sketch, and potential patent issues. | 11th Mar 1919 | Box 181 \ M11 img151 | |
| Letter discussing a carburettor sketch, its potential for a patent, and its suitability for car versus aircraft engines. | 11th Mar 1919 | Box 181 \ M11 img152 | |
| Carburettor design improvements, including the concept of a diffuser jet, and testing suggestions. | 11th Mar 1919 | Box 181 \ M11 img153 | |
| Carburettor design principles and testing on different engine types. | 17th Mar 1919 | Box 181 \ M11 img154 | |
| Design of a carburettor for a chassis. | 17th Mar 1919 | Box 181 \ M11 img155 | |
| Hand-drawn schematic of a carburettor featuring a lifting piston and air-damping mechanism. | 13th Mar 1919 | Box 181 \ M11 img156 | |
| Car performance, focusing on engine temperature, radiator blockage, and fuel consumption. | 13th Mar 1919 | Box 181 \ M11 img157 | |
| Radiator modifications and the testing of an extra water jacket on the induction pipe for car 7-CA. | 3rd Mar 1919 | Box 181 \ M11 img158 | |
| Testing of Michelin wheel studs and the use of left and right-hand threads to prevent creep. | 17th Mar 1919 | Box 181 \ M11 img159 | |
| Requesting tests on back nuts and thread direction for drawings Lec.1063 and Lec.1067. | 24th Mar 1919 | Box 181 \ M11 img160 | |
| From 'E' requesting an experiment to test the 40/50 HP clutch with different lightweight driven members. | 24th Mar 1919 | Box 181 \ M11 img161 | |
| Suitability of a Weston instrument model for a chassis, comparing it to other types. | 24th Mar 1919 | Box 181 \ M11 img162 | |
| Broken frame on one car, and modifications to the starting and braking systems on others. | 24th Mar 1919 | Box 181 \ M11 img163 | |
| Sourcing of temperature recorders for cars. | 31th Mar 1919 | Box 181 \ M11 img164 | |
| Development of a water temperature thermometer and radiator louvres, prompted by poor performance due to low-grade petrol. | 3rd Apr 1919 | Box 181 \ M11 img165 | |
| Piston design, specifically the location of the piston pin and the use of shorter connecting rods to address piston knocks. | 1st Apr 1919 | Box 181 \ M11 img166 | |
| Suggested modifications and performance issues of car 7-CA, including clutch inaccessibility, oil on brakes, overheating, and ignition problems. | 3rd Apr 1919 | Box 181 \ M11 img167 | |
| Manufacturing of pistons using two perforated scraper rings and Mr. Hall's alloy. | 3rd Apr 1919 | Box 181 \ M11 img168 | |
| Approval note for using a wiring tube on the 40/50 HP chassis. | 8th Apr 1919 | Box 181 \ M11 img169 | |
| Criticisms on scheme No.365 for a 40/50 HP float-chamber and requesting a new design. | 9th Apr 1919 | Box 181 \ M11 img170 | |
| Fuel consumption tests on a 49GB carburettor and methods for heating the air intake. | 14th Apr 1919 | Box 181 \ M11 img171 | |
| Modifications to the 40/50 HP chassis clutch brake for improved accessibility and weight reduction. | 1st Apr 1919 | Box 181 \ M11 img172 | |
| The 40/50 HP chassis, detailing minutes from a conference with Mr. Royce. | 7th May 1919 | Box 181 \ M11 img173 | |
| Design notes for a retrofittable louvre frame for the 40/50 HP chassis radiator. | 1st May 1919 | Box 181 \ M11 img174 | |
| Instructions on the design and fitting of radiators, thermostats, thermometers, pressure feed pumps, and speedometers. | 1st May 1919 | Box 181 \ M11 img175 | |
| Hand-drawn sketch of a speedometer drive mechanism. | 1st May 1919 | Box 181 \ M11 img176 | |
| Design of the speedometer drive and the finish of instrument controls. | 1st May 1919 | Box 181 \ M11 img177 | |
| The required black egg-shell finish for instruments and controls, and the layout for the instrument board on 500 chassis. | 1st May 1919 | Box 181 \ M11 img178 | |
| The instrument board layout, bonnet clip design, and carburettor float feed. | 1st May 1919 | Box 181 \ M11 img179 | |
| Technical memo detailing modifications to carburettor, shock dampers, back axle, brakes, and ignition systems. | 1st May 1919 | Box 181 \ M11 img180 | |
| Ignition ballast resistance for the 40/50 HP chassis and replacing C.A.V. lighting sets with Lucas. | 26th May 1919 | Box 181 \ M11 img181 | |
| Hand-drawn diagram of a battery ignition system showing the ballast resistance mounted underneath the coil. | 1st May 1919 | Box 181 \ M11 img182 | |
| Procurement of Lucas ignition sets, a dynamo accessibility issue, and the design requirements for a portable lamp. | 1st May 1919 | Box 181 \ M11 img183 | |
| Discussion concerning portable lamps and detailed design considerations for a new piston, including defects, over-oiling issues, and modifications to piston ring pins. | 1st May 1919 | Box 181 \ M11 img184 | |
| Recurring failure in cast-iron pistons on repair cars, recommending their production without steel stiffening plates. | 31th May 1919 | Box 181 \ M11 img185 | |
| Adoption of Michelin disc wheels, Dunlop wire wheels, and the issues with wooden wheels. | 2nd Jun 1919 | Box 181 \ M11 img186 | |
| From R to CJ regarding tyre and rim standards, and the difficulty of tyre fitting. | 2nd Jun 1919 | Box 181 \ M11 img187 | |
| Possible jelly mixture with benzol and experiences with different benzol brands. | 3rd Jul 1919 | Box 181 \ M11 img188 | |
| The proposal to illuminate the instrument board on the 40/50 HP chassis. | 8th Aug 1919 | Box 181 \ M11 img189 | |
| Query regarding an oil leak observed on the back axle torque tube joints of chassis 7 CA. | 1st Aug 1919 | Box 181 \ M11 img190 | |
| Design of rear spring pivots for the 20 HP and 40/50 HP chassis, focusing on U-bolt retention. | 1st Aug 1919 | Box 181 \ M11 img191 | |
| Engine pre-ignition from over-heated plugs and a knocking sound in car 7 CA. | 8th Aug 1919 | Box 181 \ M11 img192 | |
| From Mr. Royce regarding alterations to the priming device on a 40/50 HP chassis. | 20th Aug 1919 | Box 181 \ M11 img193 | |
| Ignition system improvements for car 1 EX, including material choices for springs and magneto accessibility. | 22th Jul 1919 | Box 181 \ M11 img194 | |
| Preliminary report on the '1 EX' car test, highlighting issues with piston knocking when cold and lubricating oil performance. | 21th Aug 1919 | Box 181 \ M11 img195 | |
| Technical memorandum discussing solutions for piston knock through improved engine lubrication systems. | 21th Aug 1919 | Box 181 \ M11 img196 | |
| The performance of car 1 EX, detailing engine compression, piston ring position, and lubrication recommendations. | 21th Aug 1919 | Box 181 \ M11 img197 | |
| Directive from Mr. Royce regarding the use of semi-flexible scuttle to dashboard attachments on all chassis. | 21th Aug 1919 | Box 181 \ M11 img198 | |
| Potential causes of piston knocks, related to lubricant, ignition timing, and piston design. | 26th Mar 1919 | Box 181 \ M11 img199 | |
| Capacity and design of a petrol tank for a 40/50 HP car, suggesting a new design and capacity. | 27th Dec 1919 | Box 181 \ M11 img200 | |
| From Mr. Royce regarding piston design, ring position, and its effect on knocking and oil scraping. | 27th Aug 1919 | Box 181 \ M11 img201 | |
| Advantages of pistons with low-positioned rings. | 27th Aug 1919 | Box 181 \ M11 img202 | |
| Technical note on standard allowances for fitting pistons to prevent piston knocks. | 27th Aug 1919 | Box 181 \ M11 img203 | |
| Failure of a pendulum steering lever, potential causes, and required follow-up actions. | 27th Aug 1919 | Box 181 \ M11 img204 | |
| The improved clutch brake for the 40/50 HP chassis. | 28th Aug 1919 | Box 181 \ M11 img205 | |
| Proposal to test extra lubrication to reduce piston knock under light load. | 1st Sep 1919 | Box 181 \ M11 img206 | |
| Use of odd-sized tyres on the 40/50 HP chassis and the potential effect on the differential. | 1st Sep 1919 | Box 181 \ M11 img207 | |
| Recommendation to replace the three-fold tool kit with a two-fold satchel for easier storage. | 6th Sep 1919 | Box 181 \ M11 img208 | |
| Piston knock issues, lubrication improvements, and the use of castor oil. | 5th Sep 1919 | Box 181 \ M11 img209 | |
| Redesign of standard bolt heads for improved production and usability. | 1st Sep 1919 | Box 181 \ M11 img210 | |
| Simplification and cost reduction of bolt production and requesting a test batch for standardisation. | 1st Sep 1919 | Box 181 \ M11 img211 | |
| Telegram from Royce regarding the unsatisfactory performance of car 49GB, with instructions for engine modifications and preparation for a ten thousand mile test. | 17th Sep 1919 | Box 181 \ M11 img212 | |
| Cause of a 'hard' feeling in car 49-GB after an engine overhaul. | 17th Sep 1919 | Box 181 \ M11 img213 | |
| Engine compression ratios, slipper wheel friction, and the status of cars 1.EX and 49-GB. | 17th Sep 1919 | Box 181 \ M11 img214 | |
| Report of impressions on chassis 49 GB, detailing issues with the engine, magneto, clutch, dynamo, and battery. | 22th Sep 1919 | Box 181 \ M11 img215 | |
| Rear shock absorbers, engine lubrication, and cylinder lubrication methods. | 1st Sep 1919 | Box 181 \ M11 img216 | |
| Issues found with the air pump, vibrations and battery system on chassis 49 GB. | 4th May 1919 | Box 181 \ M11 img217 | |
| Vehicle issues including wiring insulation, piston leakage, gearbox noise, and clutch performance. | 1st Sep 1919 | Box 181 \ M11 img218 | |
| Engine running issues, including harshness, gas leaks and vibrations on chassis 49 GB. | 23th Sep 1919 | Box 181 \ M11 img219 | |
| The production of a sylphon tube, including a dimensional sketch for a 40/50 HP chassis. | 18th Sep 1919 | Box 181 \ M11 img220 | |
| Preparation and parts required for a 10,000-mile car test. | 18th Sep 1919 | Box 181 \ M11 img221 | |
| List of proposed modifications and improvements for a car, with notes on their completion status. | 16th Sep 1919 | Box 181 \ M11 img222 | |
| Planning of a 10,000-mile car test, comparing potential locations and required vehicle modifications. | 18th Sep 1919 | Box 181 \ M11 img223 | |
| Need for a specific car body type and using external body builders for experimental cars. | 8th Sep 1919 | Box 181 \ M11 img224 | |
| Issues with harsh fabric clutches, with suggestions for mechanical improvements to the operating mechanism. | 29th Sep 1919 | Box 181 \ M11 img225 | |
| The results of lubricating a clutch with castor oil and comparing its performance. | 1st Sep 1919 | Box 181 \ M11 img226 | |
| The design of a water temperature regulator with a bypass for the 40/50 HP chassis. | 23th Sep 1919 | Box 181 \ M11 img227 | |
| Direct bypass system and an order for thermostatic units from the Sylphon Company in America. | 9th Sep 1919 | Box 181 \ M11 img228 | |
| Mr. Royce's decision to use the long chassis instead of the 'A' steering system. | 27th Sep 1919 | Box 181 \ M11 img229 | |
| Modifications to the water temperature regulator and pipe arrangement on the 40/50 HP chassis. | 27th Sep 1919 | Box 181 \ M11 img230 | |
| Engine fitted with a water temperature control. | 27th Sep 1919 | Box 181 \ M11 img231 | |
| Fitment issues with Michelin disc wheels on the 1 EX car due to unevenly spaced holes. | 23th Sep 1919 | Box 181 \ M11 img232 | |
| Weight comparison between Michelin disc wheels and Dunlop detachable wire wheels. | 23th Sep 1919 | Box 181 \ M11 img233 | |
| Inaccuracies, weight, and design concerns of Michelin disc wheels. | 24th Sep 1919 | Box 181 \ M11 img234 | |
| Testing and recommendation of Michelin disc wheels as an alternative to wire wheels, noting potential corrosion issues. | 9th Sep 1919 | Box 181 \ M11 img235 | |
| Comparison report on trembler and non-trembler ignition systems tested on an experimental car. | 26th Sep 1919 | Box 181 \ M11 img236 | |
| The performance and issues with a new type of battery ignition system. | 2nd Oct 1919 | Box 181 \ M11 img237 | |
| Alternative wiring methods, conductor insulation, and component placement on a chassis, including Mr. Royce's recommendations. | 1st Oct 1919 | Box 181 \ M11 img238 | |
| Mr. Royce's recommendations for the color coding and sizing of low tension conductors on the 40/50 HP chassis. | 1st Oct 1919 | Box 181 \ M11 img239 | |
| The use of armouring versus rubber and braided cotton for low tension wires. | 1st Oct 1919 | Box 181 \ M11 img240 | |
| Failures of the 40/50 radiator suspension during bumping tests, with suggestions for modifications. | 10th Oct 1919 | Box 181 \ M11 img241 | |
| Letter addressing a 'chunking in transmission' issue on a new chassis, detailing potential causes like premature ignition or misfiring. | 20th Oct 1919 | Box 181 \ M11 img242 | |
| List of potential engine misfiring causes and discussion of a complaint from a customer, Mr. de Salamanca. | 20th Oct 1919 | Box 181 \ M11 img243 | |
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