| Description | Date | Identifier | |
| Outlining engine testing, chassis modifications, and component testing for various car models. | 15th Mar 1929 | Box 65a \ 2 scan0253 | |
| Fitting of a balanced crankshaft to the 20-EX model. | 25th May 1921 | Box 65a \ 2 scan0254 | |
| Telegram requesting car 14 EX be sent to Dover, with instructions for the driver to return car 21 EX to Derby. | 25th May 1921 | Box 65a \ 2 scan0255 | |
| Outlining the recommended procedure for sending S.S. experimental chassis to the U.S.A. for testing and approval. | 9th Apr 1929 | Box 65a \ 2 scan0256 | |
| Supply of hubs and wheels from the U.S.A. and the costs of experimental tests. | 10th Apr 1929 | Box 65a \ 2 scan0257 | |
| Issues and improvements following a 10,000-mile test on the 22-EX car, including engine rattles, oil leaks, and starter motor failure. | 10th Apr 1929 | Box 65a \ 2 scan0258 | |
| Progress report on the preparation of the 21-EX and 22-EX experimental cars. | 18th Apr 1929 | Box 65a \ 2 scan0259 | |
| Requesting instructions to complete Chassis 21-EX, highlighting delays due to the silencer, undershields, and wiring. | 18th Apr 1929 | Box 65a \ 2 scan0260 | |
| Investigation into the loss of engine cooling water on the 'SS' chassis. | 22th Apr 1929 | Box 65a \ 2 scan0261 | |
| From Hs to SG arranging a meeting to test and discuss the 21-EX experimental car. | 25th Apr 1929 | Box 65a \ 2 scan0262 | |
| Requesting a status update on the 21-EX sample for the standardisation sheet. | 25th Apr 1929 | Box 65a \ 2 scan0263 | |
| Typed memo confirming a meeting at Bignalls Corner and discussing the fitting of 19 inch wheels to a Hooper car. | 25th Apr 1929 | Box 65a \ 2 scan0264 | |
| Requesting photographs of the 'SS' car for a catalogue, specifying the desired angle. | 29th Apr 1929 | Box 65a \ 2 scan0265 | |
| Photograph of a chauffeur-driven limousine parked in front of a London townhouse, No. 16. | 30th Apr 1929 | Box 65a \ 2 scan0266 | |
| Photographs of experimental cars 18-EX and 22-EX. | 30th Apr 1929 | Box 65a \ 2 scan0267 | |
| Inability to complete chassis 19-EX on time due to incomplete drawings and modifications. | 3rd May 1929 | Box 65a \ 2 scan0268 | |
| Faults with the fabric coupling and exhaust system on 'SS' cars, recommending a cautious approach to production. | 1st May 1929 | Box 65a \ 2 scan0269 | |
| Faults with the 22-EX car, including braking proportions, engine oil leaks, and starter motor failure. | 1st May 1929 | Box 65a \ 2 scan0270 | |
| Request for photographs of a completed open car, model 'S.S.' 23 EX, for potential use on trials cars. | 7th May 1929 | Box 65a \ 2 scan0271 | |
| Directive concerning the S.S. Chassis, detailing a production slowdown for the engine coupling and exhaust system. | 8th May 1929 | Box 65a \ 2 scan0272 | |
| From Sg. to Hs. regarding the trial of car 21-EX and a planned conference in Derby. | 8th May 1929 | Box 65a \ 2 scan0273 | |
| Request to issue a drawing of a spring and joint for an S.S. car undergoing a 10,000-mile test. | 14th May 1929 | Box 65a \ 2 scan0274 | |
| Letter arranging for the use and testing of experimental cars 21-EX and 19-EX during a holiday. | 15th May 1929 | Box 65a \ 2 scan0275 | |
| Letter regarding the performance of a 20 HP car and a request for an employee named Lidsey to have a week off at Whitsuntide. | 17th May 1929 | Box 65a \ 2 scan0276 | |
| Accompanying a set of blueprints for coachbuilders, including a correction for headlamp dimensions on a Phantom chassis drawing. | 17th May 1929 | Box 65a \ 2 scan0277 | |
| Inquiring about the availability of 'SS' cars at the Works for catalogue photography. | 24th May 1929 | Box 65a \ 2 scan0278 | |
| Test report on experimental car 19 EX, detailing its performance, handling, and engine characteristics. | 24th May 1929 | Box 65a \ 3 scan0001 | |
| Test report on a vehicle's performance, noting issues with brakes, engine cooling, clutch, and oil leaks. | 24th May 1929 | Box 65a \ 3 scan0002 | |
| Road test observations on various car models, focusing on cooling, vibration, and frame movement. | 24th May 1929 | Box 65a \ 3 scan0003 | |
| 'jellying' issues with engine mountings and frame design on an experimental chassis. | 27th May 1929 | Box 65a \ 3 scan0004 | |
| Arranging for a photographer to photograph 'SS' cars in Derby. | 27th May 1929 | Box 65a \ 3 scan0005 | |
| Loan of 'SS' car 19-EX for testing and feedback, and addressing an overheating complaint. | 27th May 1929 | Box 65a \ 3 scan0006 | |
| Report on the cooling inefficiency of car 21-EX. | 27th May 1929 | Box 65a \ 3 scan0007 | |
| Arrangements for testing an SS car at Elstree and bringing other experimental vehicles for trials. | 29th May 1929 | Box 65a \ 3 scan0008 | |
| Telegram requesting a one-week delay in sending a car. | 1st Jun 1929 | Box 65a \ 3 scan0009 | |
| Short typed memo regarding the arrangement for a car key to be delivered to London. | 11th Jun 1929 | Box 65a \ 3 scan0010 | |
| From Sg. to Hs. regarding the deferral of sending car 21-EX for a week due to decorators at a house in Northwood. | 3rd Jun 1929 | Box 65a \ 3 scan0011 | |
| The supply of an experimental 'SS' chassis for testing under American conditions. | 3rd Jun 1929 | Box 65a \ 3 scan0012 | |
| Instructions for arranging the collection, customs, and testing equipment for an experimental car in France. | 4th Jun 1929 | Box 65a \ 3 scan0013 | |
| Suggestion to name the S.S. car 'The Silent Spectre'. | 5th Jun 1929 | Box 65a \ 3 scan0014 | |
| Outlining the handover procedure for the 21-EX car for an amateur driver test. | 1st Jun 1929 | Box 65a \ 3 scan0015 | |
| Outlining the plan to send car 21-EX for testing and subsequent transfer to France. | 1st Jun 1929 | Box 65a \ 3 scan0016 | |
| Report discussing S.S. Chassis test results and comparisons, with added points on piston seizing, water temperature, and lubrication. | 7th Jun 1929 | Box 65a \ 3 scan0017 | |
| Radiator water loss and the performance of gear changes compared to the Phantom chassis. | 7th Jun 1929 | Box 65a \ 3 scan0018 | |
| Comparison of an S.S. Car chassis against the Phantom and other experimental models. | 30th May 1929 | Box 65a \ 3 scan0019 | |
| Vehicle test report detailing performance issues and observations on a Phantom model. | 30th May 1929 | Box 65a \ 3 scan0020 | |
| Typed report detailing test observations and issues found on an S.S. model car compared to a Phantom. | 7th Jun 1929 | Box 65a \ 3 scan0021 | |
| Cover note for an attached report concerning an SS. Chassis. | 7th Jun 1929 | Box 65a \ 3 scan0022 | |
| Personal impression report comparing experimental chassis models 19-EX, 18-EX, and 23-EX. | 6th Jun 1929 | Box 65a \ 3 scan0023 | |
| Test report comparing the SS Chassis against the Phantom chassis. | 6th Jun 1929 | Box 65a \ 3 scan0024 | |
| Progress report on the status and testing of experimental cars, including several EX models. | 7th Jun 1929 | Box 65a \ 3 scan0025 | |
| Progress report on the 20 HP car tests and experimental 'R' aero engine work. | 7th Jun 1929 | Box 65a \ 3 scan0026 | |
| Progress report on the development and testing of 'H' and 'F' type aero engines, including modifications to blowers and carburettors. | 7th Jun 1929 | Box 65a \ 3 scan0027 | |
| Dropping the use of mineral oil for a test and awaiting designs for F. cylinder block modifications. | 11th Jun 1929 | Box 65a \ 3 scan0028 | |
| Internal memorandum discussing the testing strategy for the 21-EX experimental car's water temperature and overheating issues. | 11th Jun 1929 | Box 65a \ 3 scan0029 | |
| Test report and feedback on the S.S. Chassis, models 21-EX and 22-EX. | 12th Jun 1929 | Box 65a \ 3 scan0030 | |
| Comparison of issues including clutch slip, ride harshness, and engine detonation on experimental car models 19-EX, 21-EX, and 22-EX. | 12th Jun 1929 | Box 65a \ 3 scan0031 | |
| 'Secret' internal memorandum outlining strict secrecy protocols for the 'SS' chassis project and modified 20 HP model. | 13th Jun 1929 | Box 65a \ 3 scan0032 | |
| Missing boiling warning light and frequent silencer popping on car 21-EX. | 20th Jun 1929 | Box 65a \ 3 scan0033 | |
| Engine noise and roughness, detailing the configuration of three S.S. chassis. | 20th Jun 1929 | Box 65a \ 3 scan0034 | |
| Continued memo on a two-branch exhaust box, steering, and the 21-EX car with a Phantom front axle. | 21th Jun 1929 | Box 65a \ 3 scan0035 | |
| Water boiling indicator lamp and exhaust popping on the 21-EX car. | 21th Jun 1929 | Box 65a \ 3 scan0036 | |
| Performance issues and improvements on experimental car chassis, including noise, speed, and steering. | 26th Jun 1929 | Box 65a \ 3 scan0037 | |
| Continued memorandum discussing a 'boom' noise in the back of a car, quoting a contradictory observation. | 26th Jun 1929 | Box 65a \ 3 scan0038 | |
| Issues and test results for experimental cars, including engine noise, speed, heat, steering, and fuel supply. | 26th Jun 1929 | Box 65a \ 3 scan0039 | |
| Continued page of a report discussing observations of a 'boom' sound in a car. | 25th Jun 1929 | Box 65a \ 3 scan0040 | |
| Comparing chassis 21-EX to a Phantom, noting improvements but also significant concerns about increased engine noise. | 25th Jun 1929 | Box 65a \ 3 scan0041 | |
| Comparative car trials, focusing on noise, performance, and improvements needed against competitor vehicles. | 25th Jun 1929 | Box 65a \ 3 scan0042 | |
| Secret memo discussing criticisms and proposed improvements for a car, with comparisons made to the Phantom model. | 25th Jun 1929 | Box 65a \ 3 scan0043 | |
| Secret report detailing vehicle performance issues and suggestions for improvement, covering steering, petrol feed, and engine components. | 25th Jun 1929 | Box 65a \ 3 scan0044 | |
| The appearance of the chassis cross member and bonnet, with concerns about noise at speed. | 25th Jun 1929 | Box 65a \ 3 scan0045 | |
| Engine 'fuss or roar' by modifying the carburettor and defending recent chassis improvements. | 26th Jun 1929 | Box 65a \ 3 scan0046 | |
| Variations in steering, engine performance, and carburetter adjustments for a new chassis, possibly the Phantom II. | 28th Jun 1929 | Box 65a \ 3 scan0047 | |
| Field report on a car's journey, maintenance, and tyre condition from Grenoble. | 30th Jun 1929 | Box 65a \ 3 scan0048 | |
| Increased engine speeds and vibrations in faster cars. | 1st Jul 1929 | Box 65a \ 3 scan0049 | |
| List of queries and answers comparing the 'SS' model with the 'Phantom' model. | 1st Aug 1924 | Box 65a \ 3 scan0050 | |
| Question and answer document regarding vehicle lubrication and fluid quantities. | 1st Aug 1924 | Box 65a \ 3 scan0051 | |
| Q&A document page covering oil change intervals, oil pressure failures, and tappet clearances. | 1st Aug 1924 | Box 65a \ 3 scan0052 | |
| Page of questions and answers regarding mechanical settings for the Phantom model, including carburetter, fuel consumption, and brake adjustments. | 1st Aug 1924 | Box 65a \ 3 scan0053 | |
| List of brake system movement specifications and checks for Phantom and 20 HP models. | 1st Aug 1924 | Box 65a \ 3 scan0054 | |
| Series of questions and handwritten answers regarding brake effort, clutch, and hydraulic damper adjustments. | 1st Jul 1929 | Box 65a \ 3 scan0055 | |
| Engine noise ('fuss or roar') and clarifying the positive impression of improvements made to a chassis. | 1st Jul 1929 | Box 65a \ 3 scan0056 | |
| Improvements to 'SS' cars, persistent noise issues, and a proposal for comparative tests against a Phantom. | 1st Jul 1929 | Box 65a \ 3 scan0057 | |
| Secret memo from 'Sg' to 'Hs' arranging a road trial for car 21-EX to investigate ongoing noise issues. | 3rd Jul 1929 | Box 65a \ 3 scan0058 | |
| Arranging a meeting at Bignalls Corner regarding 'SS' cars. | 8th Jul 1929 | Box 65a \ 3 scan0059 | |
| Road test report on hotel letterhead detailing a journey from Grenoble to Auxerre and the car's performance. | 3rd Jul 1929 | Box 65a \ 3 scan0060 | |
| Ineffective front brakes and light rear suspension after a road test to Paris. | 3rd Jul 1929 | Box 65a \ 3 scan0061 | |
| Production schedule and timeline for the 40/50-HP Chassis, K2 series. | 3rd Jul 1929 | Box 65a \ 3 scan0062 | |
| Outlining suggested areas for experimental and development work on the chassis. | 1st Jul 1929 | Box 65a \ 3 scan0063 | |
| List of required design improvements and ongoing technical issues, being page 2 of a larger document. | 4th Jul 1929 | Box 65a \ 3 scan0064 | |
| Road test report on car 21-EX, diagnosing a high-speed petrol starvation issue caused by the autovac system, also noting high fuel consumption and steering performance. | 4th Jul 1929 | Box 65a \ 3 scan0065 | |
| Steering performance and potential wandering issues on a Verberley Patrol car following a road test. | 30th Aug 1934 | Box 65a \ 3 scan0066 | |
| Vehicle performance issues including overrun vibration, brake problems, and high water temperature during a trial. | 5th Jul 1929 | Box 65a \ 3 scan0067 | |
| Investigating the source of a booming engine noise in S.S. and 21-EX cars. | 5th Jul 1929 | Box 65a \ 3 scan0068 | |
| Proposal to visit Paris to repeat tests on vehicle 21-EX and assess improvements to axles and steering. | 6th Jul 1929 | Box 65a \ 3 scan0069 | |
| Testing for body booming, general engine noise, and front axle communication. | 6th Jul 1929 | Box 65a \ 3 scan0070 | |
| List of non-standard specifications for the rebuild of the 20-EX car. | 8th Jul 1929 | Box 65a \ 3 scan0071 | |
| Publicity strategy for a new 'SS' model, including commissioning an article from journalist Capt. Gordon Aston. | 9th Jul 1929 | Box 65a \ 3 scan0072 | |
| Faults found in a Bentley, including a 'jellied' radiator and defective steering. | 10th Jul 1929 | Box 65a \ 3 scan0073 | |
| Recommending the 18-EX car for a demonstration after tests on the Wellyn By-pass. | 11th Jul 1929 | Box 65a \ 3 scan0074 | |
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