| Description | Date | Identifier | |
| Comparison drawing showing an existing scheme and a suggested modification for a mechanical component, possibly a seal or bearing assembly. | 3rd Feb 1939 | Box 152 \ 2 scan0242 | |
| Clarifying the piece number for VG.90 discs and the material it has replaced. | 3rd Feb 1939 | Box 152 \ 2 scan0243 | |
| Letter to The Bifurcated & Tubular Rivet Co. Ltd. about unsatisfactory results from solid copper tubular rivets. | 14th Feb 1939 | Box 152 \ 2 scan0244 | |
| Urgent internal memo requesting the order of one gross of tinmans leaded solid copper bifurcated tubular rivets. | 14th Feb 1939 | Box 152 \ 2 scan0245 | |
| Letter to Ferodo Ltd. regarding difficulties in riveting a VG.90 friction ring and servo driven plate. | 15th Feb 1939 | Box 152 \ 2 scan0246 | |
| Requesting the dispatch of a Servo disc and Friction ring to Ferodo Ltd. | 15th Feb 1939 | Box 152 \ 2 scan0247 | |
| Letter from The Bifurcated & Tubular Rivet Co. Ltd. regarding a technical representative visit and an order of rivets. | 15th Feb 1939 | Box 152 \ 2 scan0248 | |
| Letter from a rivet company discussing super-charger clutch facings, rivet samples, and a new anvil. | 22th Feb 1939 | Box 152 \ 2 scan0249 | |
| Issues with broken or loose servo friction discs, attributing the cause to incorrect rivet and hole sizes. | 27th Feb 1939 | Box 152 \ 2 scan0250 | |
| Requesting an official order for friction discs that have been delivered. | 3rd Mar 1939 | Box 152 \ 2 scan0251 | |
| Order of tinmans head copper rivets for B.V. and B.50 servos. | 30th Mar 1939 | Box 152 \ 2 scan0252 | |
| Requesting the manufacture of three sets of modified servo cams for hydraulic brakes. | 30th Mar 1939 | Box 152 \ 2 scan0253 | |
| Instruction to use 30° servo cams instead of 33° on future experimental chassis due to the use of VG.90 servo linings. | 13th Apr 1939 | Box 152 \ 2 scan0254 | |
| Instruction to modify the servo cam angle from 35° to 30° on experimental cars with front hydraulic brakes. | 15th Apr 1939 | Box 152 \ 2 scan0255 | |
| Instructing a change in the angle of Servo cams from 35° to 30° and for the modification to be made retrospective. | 17th Apr 1939 | Box 152 \ 2 scan0256 | |
| Request to issue an official order to Ferodo Ltd. for servo discs and liners. | 5th May 1939 | Box 152 \ 2 scan0257 | |
| Line diagram of a servo fitting, showing two schemes with force calculations. | 26th Jul 1937 | Box 152 \ 2 scan0258 | |
| Modifications to the gearbox and servo drive for Senior Range Cars, specifically for fitting a Tecalemit drive. | 7th Mar 1940 | Box 152 \ 2 scan0259 | |
| Alteration note regarding a servo-operated hydraulic master cylinder for alternative chassis lengths. | 7th May 1940 | Box 152 \ 2 scan0260 | |
| Issues and proposed modifications for the Senior Range Servo Motor. | 23th Sep 1940 | Box 152 \ 2 scan0261 | |
| Packing note for parts including a servo lining and synchromesh sleeve sent to Derby. | 24th Sep 1940 | Box 152 \ 2 scan0262 | |
| Clearance and tolerance issues for the pins in a servo drive mechanism. | 20th Oct 1940 | Box 152 \ 2 scan0263 | |
| Modifications to the dimensions of servo driving pins and the central hole of the servo plate. | 22th Oct 1940 | Box 152 \ 2 scan0264 | |
| Manufacture of a water-excluding bronze diaphragm for a Servo gearbox, suggesting a two-part, dip-soldered construction. | 4th Nov 1940 | Box 152 \ 2 scan0265 | |
| Inquiry to Cornercroft Ltd. regarding the manufacture of a special phosphor bronze spring plate, suggesting pressing as an alternative to spinning. | 6th Nov 1940 | Box 152 \ 2 scan0266 | |
| Letter to Vandervell Products Ltd. requesting two pairs of experimental friction discs. | 12th Nov 1940 | Box 152 \ 2 scan0267 | |
| Drawing of a Friction Lining. | 11th Jan 1939 | Box 152 \ 2 scan0268 | |
| Issues and suggested improvements for the rationalised brake system. | 4th Nov 1940 | Box 152 \ 2 scan0269 | |
| Gearbox oil ingress, servo drive improvements, and high brake lining wear. | 4th Nov 1940 | Box 152 \ 2 scan0270 | |
| Suggested experiments on car braking systems, including efficiency, cooling, clearances, handbrakes, and rear equalisers. | 4th Nov 1940 | Box 152 \ 2 scan0271 | |
| Confirmation letter to The British Tyre & Rubber Co. Ltd. regarding the supply of two oil sealing rings. | 5th Dec 1940 | Box 152 \ 2 scan0272 | |
| Request to issue an official order for two experimental oil sealing rings to The British Tyre & Rubber Company. | 5th Dec 1940 | Box 152 \ 2 scan0273 | |
| Requesting the dispatch of a servo driving plate and rivets to Vandervell Products Ltd for lining. | 8th Dec 1940 | Box 152 \ 2 scan0274 | |
| Querying a price discrepancy for Spring Plate GB.5114, used in the B.V. servo. | 11th Dec 1940 | Box 152 \ 2 scan0275 | |
| The manufacture of a special spring plate with deep corrugation for water exclusion from a servo. | 13th Dec 1940 | Box 152 \ 2 scan0276 | |
| Effectiveness of a rubber seal for water exclusion from the servo. | 17th Dec 1940 | Box 152 \ 2 scan0277 | |
| Costs, production, and potential faults of a new experimental spring plate for servo water exclusion. | 13th Dec 1940 | Box 152 \ 2 scan0278 | |
| Request to dispatch a cast iron mandrel on loan to The British Tyre & Rubber Co Ltd. | 22th Jan 1941 | Box 152 \ 2 scan0279 | |
| Request to produce a detail drawing for a mould for a rubber ring surrounding the servo. | 30th Apr 1941 | Box 152 \ 2 scan0280 | |
| Ongoing servo troubles, specifically 'shudder', and the need for design modifications on senior range cars. | 2nd Feb 1944 | Box 152 \ 2 scan0281 | |
| Servo shudder problems in senior range cars and proposing design modifications. | 2nd Feb 1944 | Box 152 \ 2 scan0282 | |
| Departmental memo regarding the rectification of noisy silencers on cars already on the road. | 15th Dec 1910 | Box 152 \ 3 scan0001 | |
| Urgent memo requesting a modification to the silencer exit nozzle to stop a booming noise in closed cars. | 21th Dec 1910 | Box 152 \ 3 scan0002 | |
| To Mr. Swetnam to investigate making the exhaust pipes straight instead of bent. | 5th Oct 1911 | Box 152 \ 3 scan0003 | |
| Meeting minutes discussing explosions in silencers and proposed throttle and nozzle modifications. | 28th Nov 1911 | Box 152 \ 3 scan0004 | |
| Meeting minutes discussing modifications to silencer and exhaust pipe designs. | 7th Dec 1911 | Box 152 \ 3 scan0005 | |
| Procedure for power testing cars by dismantling the exhaust system. | 5th Mar 1912 | Box 152 \ 3 scan0006 | |
| Technical description and illustration of the 'Nest-o-Cups' silencer. | 12th Apr 1912 | Box 152 \ 3 scan0007 | |
| Silencer bracket made in aluminium to reduce weight. | 14th Dec 1911 | Box 152 \ 3 scan0008 | |
| The failure of an aluminium silencer bracket after a 300-mile test. | 18th May 1912 | Box 152 \ 3 scan0009 | |
| Investigation into why Colonial type silencers are noisy and how they can be cured while maintaining ground clearance. | 6th Jan 1912 | Box 152 \ 3 scan0010 | |
| Article on the theory and construction of exhaust silencers from 'The Autocar' magazine. | 13th Jul 1912 | Box 152 \ 3 scan0011 | |
| Article from 'The Autocar' magazine discussing the design principles and various types of vehicle exhaust silencers. | 13th Jul 1912 | Box 152 \ 3 scan0012 | |
| Article from 'The Autocar' magazine discussing the design and principles of various automobile silencers with diagrams. | 13th Jul 1912 | Box 152 \ 3 scan0013 | |
| Article from 'The Autocar' magazine discussing and comparing various designs of automobile silencers. | 13th Jul 1912 | Box 152 \ 3 scan0014 | |
| Page from The Autocar magazine discussing and illustrating various designs of automobile silencers. | 13th Jul 1912 | Box 152 \ 3 scan0015 | |
| Article from 'The Autocar' magazine discussing and illustrating various designs of engine silencers. | 13th Jul 1912 | Box 152 \ 3 scan0016 | |
| Instructions for a silencer and exhaust scheme suggested by Mr. Royce. | 15th Jul 1912 | Box 152 \ 3 scan0017 | |
| To Mr. Royce regarding a new exhaust pipe scheme for large and small petrol tanks. | 25th Jul 1912 | Box 152 \ 3 scan0018 | |
| Design of a silencer's swan neck and drain plug. | 25th Nov 1912 | Box 152 \ 3 scan0019 | |
| Experiment testing a Swan Neck Silencer Pipe made of heavier material to cure a booming sound. | 17th Jul 1913 | Box 152 \ 3 scan0020 | |
| Typed copy of a memorandum regarding a Swan Neck Silencer Pipe and its weight. | 9th Aug 1913 | Box 152 \ 3 scan0021 | |
| Noisy colonial silencers. | 20th Jul 1912 | Box 152 \ 3 scan0022 | |
| Request to issue an X number for fitting an intermediate exhaust pipe E.3350 for testing purposes. | 3rd Feb 1914 | Box 152 \ 3 scan0023 | |
| To cancel an old experiment concerning an Intermediate Exhaust Pipe. | 12th Mar 1914 | Box 152 \ 3 scan0024 | |
| Letter from The Wolsey Engineering Co., Ltd. following up on a sample silencer sent for testing. | 26th May 1920 | Box 152 \ 3 scan0025 | |
| Recommendation to adopt bolted flanges for main silencer unions on future 40/50 HP designs. | 2nd May 1924 | Box 152 \ 3 scan0026 | |
| Epidemic of complaints about rattles and exhaust blows from the main silencer unions. | 3rd May 1924 | Box 152 \ 3 scan0027 | |
| Suggesting an inquiry into a new exhaust box design offered by Mr. Mays-smith. | 31th Oct 1924 | Box 152 \ 3 scan0028 | |
| Letter requesting a description and claims made for a specific motor-car exhaust box. | 1st Nov 1924 | Box 152 \ 3 scan0029 | |
| Letter discussing the performance claims of the 'ASPER' Silencer and its potential for Aero Engines. | 4th Nov 1924 | Box 152 \ 3 scan0030 | |
| Fitting and adjustment instructions for The Asper Silencer. | 4th Nov 1924 | Box 152 \ 3 scan0031 | |
| Page discussing exhaust welding, silencer performance, and engine power increase. | 11th May 1925 | Box 152 \ 3 scan0032 | |
| New form of exhaust silencer for the 'New Phantom' car. | 11th May 1925 | Box 152 \ 3 scan0033 | |
| Letter to N.P. Sorrell Straussler requesting a description and drawings of a new Exhaust Silencer. | 12th May 1925 | Box 152 \ 3 scan0034 | |
| Telegram arranging a meeting for the experimental department to see Mr. Straussler about an International Silencer. | 25th Mar 1921 | Box 152 \ 3 scan0035 | |
| Letter from The International Silencer Company regarding the trial of a 'Ghost' silencer. | 30th Jun 1925 | Box 152 \ 3 scan0036 | |
| Letter to The International Silencer Co. refusing to test a silencer without further data and requesting drawings. | 14th Jul 1925 | Box 152 \ 3 scan0037 | |
| Enclosed cutting on a new silencer system from a French technical paper. | 20th Sep 1926 | Box 152 \ 3 scan0038 | |
| French-language description of a vacuum-acting car silencer. | 1st Oct 1926 | Box 152 \ 3 scan0039 | |
| Expressing skepticism about a silencer design, requesting a working model for evaluation. | 1st Oct 1926 | Box 152 \ 3 scan0040 | |
| The Crane Silencer, quoting a letter from Mr. Crane regarding a muffler and exhaust pipe combination. | 17th Dec 1926 | Box 152 \ 3 scan0041 | |
| Requesting an opinion on papers regarding an exhaust silencer handed over by the Secretary of the Royal Aero Club. | 27th Mar 1928 | Box 152 \ 3 scan0042 | |
| Requesting an opinion on papers about an exhaust silencer from the Royal Aero Club. | 27th Mar 1928 | Box 152 \ 3 scan0043 | |
| Recommending a silencer for the noisy release air discharge from an SS vacuum pump. | 23th Jan 1929 | Box 152 \ 3 scan0044 | |
| Blueprint detailing the arrangement of a vacuum pump silencer for a super sports engine. | 17th Feb 1922 | Box 152 \ 3 scan0045 | |
| Promotional letter from the Vortex Silencer Company about their exhaust silencer. | 12th Aug 1929 | Box 152 \ 3 scan0046 | |
| Continuation sheet from Vortex Silencer Co., Ltd. detailing their perfected silencer and patent numbers. | 12th Nov 1929 | Box 152 \ 3 scan0047 | |
| The road test of a cast aluminium silencer system on car 20-EX. | 12th Nov 1929 | Box 152 \ 3 scan0048 | |
| Proposal to improve an exhaust system to reduce spitting and booming noises by modifying the expansion chamber and pipes. | 12th Nov 1929 | Box 152 \ 3 scan0049 | |
| Letter to The Vortex Silencer Co. Ltd. requesting information on silencers supplied for test purposes on a 20/25 HP car. | 23th May 1930 | Box 152 \ 3 scan0050 | |
| Letter from Vortex Silencer Company Ltd arranging a meeting in Derby. | 27th May 1930 | Box 152 \ 3 scan0051 | |
| Letter from Vortex Silencer Company Ltd. following up on the test of a sample silencer. | 20th Jan 1931 | Box 152 \ 3 scan0052 | |
| Letter to Vortex Silencer Co. Ltd. discussing the results of testing two sample silencers and requesting a quotation. | 21th Jan 1931 | Box 152 \ 3 scan0053 | |
| Blueprint illustrating the design and airflow of two Vortex silencer types, 'A' and 'B'. | 22th Jan 1931 | Box 152 \ 3 scan0054 | |
| Letter from Vortex Silencer Company Ltd acknowledging successful tests and requesting required quantities for a price quote on 'A' type silencers for 20/25HP and Phantom II models. | 22th Jan 1931 | Box 152 \ 3 scan0055 | |
| Letter to Vortex Silencer Co. Ltd. requesting a price quote for 'A' type silencers for the 20/25 HP and Phantom II models. | 27th Jan 1931 | Box 152 \ 3 scan0056 | |
| Acquisition and analysis of a Studebaker car silencer for research purposes. | 3rd Nov 1931 | Box 152 \ 3 scan0057 | |
| Letter from Chillcotts Ltd. proposing their 'Cylo' silencers for 1932 productions. | 23th Nov 1931 | Box 152 \ 3 scan0058 | |
| Advertisement for the Chillcotts 'Cylo' patented silencer. | 27th Nov 1931 | Box 152 \ 3 scan0059 | |
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