| Description | Date | Identifier | |
| Performance graph and analysis comparing different exhaust manifold and silencer configurations. | 13th Apr 1938 | Box 86 \ 3 scan0219 | |
| The use of mild steel downpipes on 'A' Series Bentley chassis. | 14th May 1938 | Box 86 \ 3 scan0220 | |
| Analysis of power loss in a Bentley exhaust manifold and silencer system. | 13th Apr 1938 | Box 86 \ 3 scan0221 | |
| Inferiority of the standard Bentley exhaust system compared to a dual system fitted to the Jaguar. | 22th Apr 1938 | Box 86 \ 3 scan0222 | |
| Potential noise issue with the 25HP Bensport synchro-mesh gearbox when engaging first gear. | 29th Feb 1932 | Box 86 \ 4 scan0001 | |
| Difficulty of engaging first gear in a 'Bensport' synchro-mesh gearbox and a subsequent recommendation for sports cars. | 5th Mar 1932 | Box 86 \ 4 scan0002 | |
| Suggestion to modify the Bensport Gearbox to prevent the reverse gear from balking the change down to first gear. | 8th Mar 1932 | Box 86 \ 4 scan0003 | |
| Modifications for a left-handed car, including a new gearbox and chassis. | 12th Apr 1932 | Box 86 \ 4 scan0004 | |
| Technical memorandum comparing gearbox designs, gear ratios, and stresses for the B.S. and Peregrine models. | 15th Apr 1932 | Box 86 \ 4 scan0005 | |
| Design analysis of a synchromesh gearbox with direct control, discussing striking forks, interlock mechanisms, and reverse stops. | 15th Apr 1932 | Box 86 \ 4 scan0006 | |
| Note regarding enclosed drawings of a Peregrine gearbox and an L.H. Phantom change gear tower. | 5th May 1932 | Box 86 \ 4 scan0007 | |
| Design of the reverse pinion, gear ratios, and related components for various gearboxes. | 5th May 1932 | Box 86 \ 4 scan0008 | |
| Design proposal for a Bensport & Peregrine gearbox reverse shaft to economise on length and cost. | 20th May 1932 | Box 86 \ 4 scan0009 | |
| Reverse pinion and jaw clutch design, including a diagram of a proposed hub and sleeve. | 20th May 1932 | Box 86 \ 4 scan0010 | |
| Interchangeability of the Bensport and Peregrine gearboxes and the perception of central gear changes. | 11th Jun 1932 | Box 86 \ 4 scan0011 | |
| Confirming the decision for a right-hand gear change on the Peregrine model over a central change. | 14th Jun 1932 | Box 86 \ 4 scan0012 | |
| Modifications and specifications for the Bensport and Peregrine gearbox. | 8th Jul 1932 | Box 86 \ 4 scan0013 | |
| Series of numbered points detailing adjustments and manufacturing methods for gearbox components. | 1st Aug 1932 | Box 86 \ 4 scan0014 | |
| New gearbox and clutch arrangement, scheme 3526, and the steering column design. | 1st Aug 1932 | Box 86 \ 4 scan0015 | |
| Letter to Mr. Wormald comparing the gearbox configurations of the Peregrine and Bensport models. | 27th Aug 1932 | Box 86 \ 4 scan0016 | |
| Modifications to the Bensport Gearbox, including strengthened shafts and new gear ratios. | 24th Sep 1932 | Box 86 \ 4 scan0017 | |
| Technical memo discussing the design of the Bensport gearbox, focusing on its spigot-less alignment. | 1st Oct 1932 | Box 86 \ 4 scan0018 | |
| Modifications and assembly procedure changes for the Bensport gearbox. | 8th Oct 1932 | Box 86 \ 4 scan0019 | |
| Design and mechanics of the Bensport change gear tower and lever. | 28th Oct 1932 | Box 86 \ 4 scan0020 | |
| Design specifications and considerations for the Bensport gearbox. | 5th Nov 1932 | Box 86 \ 4 scan0021 | |
| Progress of work on the Bensport gearbox and related parts. | 10th Nov 1932 | Box 86 \ 4 scan0022 | |
| Progress and strategic importance of the Bensport Gearbox project. | 11th Nov 1932 | Box 86 \ 4 scan0023 | |
| Modification to the Bensport Gearbox to remedy an excessive overhang of the 2nd speed slider. | 2nd Nov 1932 | Box 86 \ 4 scan0024 | |
| Technical memorandum regarding the design of the Bensport gearbox, third motion shaft, and servo. | 14th Nov 1932 | Box 86 \ 4 scan0025 | |
| Page discussing the speedometer drive and requirements with the A.T. Co. | 14th Nov 1932 | Box 86 \ 4 scan0026 | |
| Strengthening of the 1st and 3rd motion shafts for the Bensport gearbox. | 16th Nov 1932 | Box 86 \ 4 scan0027 | |
| Points from a telephone conversation regarding the Bensport Gearbox design. | 17th Nov 1932 | Box 86 \ 4 scan0028 | |
| Proposal affected by the method of staying the foot pedal shaft. | 17th Nov 1932 | Box 86 \ 4 scan0029 | |
| Modifications to the fulcrum pin for the Bensport gearbox hand brake lever. | 22th Nov 1932 | Box 86 \ 4 scan0030 | |
| Modifications to the Bensport gearbox, specifically the 3rd motion shaft and a new oil retaining disc. | 29th Nov 1932 | Box 86 \ 4 scan0031 | |
| Modifications to the actuating shafts of the Bensport gearbox. | 29th Nov 1932 | Box 86 \ 4 scan0032 | |
| Bensport gearbox, its suspension, adjustment, and oil retention scheme. | 30th Nov 1932 | Box 86 \ 4 scan0033 | |
| Temporary scheme for a helical second speed gear for the Bensport model. | 29th Dec 1932 | Box 86 \ 4 scan0034 | |
| Clearance between engaging teeth on helical second-speed gears for various models. | 14th Jan 1933 | Box 86 \ 4 scan0035 | |
| Permanent scheme for a helical second-speed gear for the Bensport model. | 14th Jan 1933 | Box 86 \ 4 scan0036 | |
| Design alterations for the Bensport gearbox actuating shafts, proposing a new design. | 18th Jan 1933 | Box 86 \ 4 scan0037 | |
| Bensport gearbox and damper governor drive. | 19th Jan 1933 | Box 86 \ 4 scan0038 | |
| Suggestions for higher indirect gear ratios for the Bensport model. | 24th Jan 1933 | Box 86 \ 4 scan0039 | |
| Suggested gear ratios for the Bensport gearbox. | 25th Jan 1933 | Box 86 \ 4 scan0040 | |
| Higher gear ratios for a Bensport car and requesting an altered 3rd gear ratio. | 26th Jan 1933 | Box 86 \ 4 scan0041 | |
| Bensport 25 HP gearbox and the incorporation of altered gear ratios. | 30th Jan 1933 | Box 86 \ 4 scan0042 | |
| Specification for building a 20/25 gearbox with altered ratios for Bensport. | 8th Feb 1933 | Box 86 \ 4 scan0043 | |
| Confirming that the Drawing Office will issue details for a Bensport gearbox with an altered gear ratio. | 10th Feb 1933 | Box 86 \ 4 scan0044 | |
| Modification to the gearbox for the Bensport model. | 10th Feb 1933 | Box 86 \ 4 scan0045 | |
| Modifications to coupling teeth for the silent second speed gear. | 23th Feb 1933 | Box 86 \ 4 scan0046 | |
| Risks and progress of tests on the Bensport & 25 HP gearbox and other new components. | 28th Feb 1933 | Box 86 \ 4 scan0047 | |
| Trial of a new Bentley gear lever with a knob made of ebonite or bakelite to improve appearance and reduce rattle. | 2nd Mar 1933 | Box 86 \ 4 scan0048 | |
| Alteration of gear ratios for a second Bentley Bensport model. | 1st May 1933 | Box 86 \ 4 scan0049 | |
| Revised design for the Bentley change speed knob, proposing a change from steel to bakelite. | 2nd May 1933 | Box 86 \ 4 scan0050 | |
| Confirming satisfactory tests of Bensport gear ratios and instructing for production. | 3rd May 1933 | Box 86 \ 4 scan0051 | |
| Decision to adopt a new gearbox design for the 3.5 Litre Bentley and transfer old parts to the 20/25 model. | 3rd May 1933 | Box 86 \ 4 scan0052 | |
| Fitment of a Marles Weller steering gear and requesting clarification on compatibility. | 3rd May 1933 | Box 86 \ 4 scan0053 | |
| Confirming the shortening of the change speed lever by 1 inch for the 3 1/2 litre Bentley Car. | 10th May 1933 | Box 86 \ 4 scan0054 | |
| Modification to the Bensport Change Speed Lever for testing purposes. | 10th May 1933 | Box 86 \ 4 scan0055 | |
| Suggesting modifications to a sliding handle reverse actuation for a gear lever. | 29th Jun 1933 | Box 86 \ 4 scan0056 | |
| Technical memo discussing the design of a sliding handle for gear lever reverse actuation, comparing different schemes. | 29th Jun 1933 | Box 86 \ 4 scan0057 | |
| The sliding handle reverse actuation for a gear lever. | 30th Jun 1933 | Box 86 \ 4 scan0058 | |
| Modifications to the sliding handle actuation for a gear lever to reduce construction costs. | 15th Jul 1933 | Box 86 \ 4 scan0059 | |
| Analysis of a gear lever handle vibration problem on a Bentley and proposed modifications to cure it. | 14th Sep 1933 | Box 86 \ 4 scan0060 | |
| Vibrations and noise in a gear lever, with a request for tests on Bentley and 20/25 models. | 14th Sep 1933 | Box 86 \ 4 scan0061 | |
| Rubber insulated gearbox rear support, referencing drawing N. Sch. 3829. | 25th Sep 1933 | Box 86 \ 4 scan0062 | |
| Confirming a request to fix a rattling gear lever knob before production. | 3rd Oct 1933 | Box 86 \ 4 scan0063 | |
| Proposed change to the Bentley Change Speed Lever Handle manufacturing process. | 19th Oct 1933 | Box 86 \ 4 scan0064 | |
| Revised Bentley gear lever knob design without a metal insert, noting changes in dimensions and benefits. | 23th Oct 1933 | Box 86 \ 4 scan0065 | |
| Standardisation of an anti-rattle change speed gear lever knob. | 2nd Nov 1933 | Box 86 \ 4 scan0066 | |
| Modification to the 2nd speed dogs following a 10,000-mile test on Hancock's car. | 21th Dec 1933 | Box 86 \ 4 scan0067 | |
| Blueprint detailing a modification to a 2nd speed driver gear, showing every alternate tooth reduced. | 21th Dec 1933 | Box 86 \ 4 scan0068 | |
| Modification to the 2nd speed dogs for Bentley, 20/25, and Phantom models. | 2nd Jan 1934 | Box 86 \ 4 scan0069 | |
| Standardisation of a second gear with alternative relieved teeth to facilitate easier gear changing. | 20th Dec 1933 | Box 86 \ 4 scan0070 | |
| Synchromesh 2nd speed design and the arrangements being made for a provisional patent. | 29th Jan 1934 | Box 86 \ 4 scan0071 | |
| Programme for implementing second-speed synchromesh gearboxes on various car models. | 29th Jan 1934 | Box 86 \ 4 scan0072 | |
| Wear on thrust washers on a third motion shaft for a Bentley, causing a 10,000-mile test to be stopped. | 26th Feb 1934 | Box 86 \ 4 scan0073 | |
| Persistent vibration rattle issue with the Bentley change gear lever. | 6th Mar 1934 | Box 86 \ 4 scan0074 | |
| Rattling change speed lever knob and suggesting a rubber washer as a solution. | 9th Mar 1934 | Box 86 \ 4 scan0075 | |
| Cause and potential cures for a rattling Bentley change speed lever. | 19th Mar 1934 | Box 86 \ 4 scan0076 | |
| Gearbox test report for a B-4 car fitted with a Peregrine gearbox. | 23th Apr 1934 | Box 86 \ 4 scan0077 | |
| Position of the Peregrine gearbox and synchromesh second speed for the Bentley. | 24th Apr 1934 | Box 86 \ 4 scan0078 | |
| Modifications for the Peregrine Gearbox, including a new bearing and material changes for motion shafts. | 3rd May 1934 | Box 86 \ 4 scan0079 | |
| Blueprint of a sideshaft bearing for a Peregrine gearbox in a Bentley chassis. | 2nd May 1934 | Box 86 \ 4 scan0080 | |
| Details on fitting an independent Peregrine Gearbox and frame stiffening for a Bentley chassis. | 4th May 1934 | Box 86 \ 4 scan0081 | |
| List of specifications and modifications for gearbox, clutch, and servo components. | 4th May 1934 | Box 86 \ 4 scan0082 | |
| List of proposed modifications to a gearbox and chassis arrangement, referencing drawing Hs.1382. | 4th May 1934 | Box 86 \ 4 scan0083 | |
| The specifications and modifications required for a new high ratio gearbox for a Bentley. | 26th May 1934 | Box 86 \ 4 scan0084 | |
| Calculation and comparison of tooth stresses and pitch line loading for various gearboxes. | 30th May 1934 | Box 86 \ 4 scan0085 | |
| Relative gearbox load values and lubrication practices for various models. | 30th May 1934 | Box 86 \ 4 scan0086 | |
| Scheme for getting oil into the centre of gearbox shafts by means of screw threads. | 31th May 1934 | Box 86 \ 4 scan0087 | |
| Tests for an 'Acme Thread' lubrication scheme for a gearbox shaft. | 31th May 1934 | Box 86 \ 4 scan0088 | |
| Test results on sleeve clearance, pressure stabilization, and temperature effects on delivery. | 31th May 1934 | Box 86 \ 4 scan0089 | |
| Blueprint detailing the lubrication scheme for an Acme thread steering worm. | 16th May 1934 | Box 86 \ 4 scan0090 | |
| Two graphs detailing the performance of an Acme thread lubrication scheme for a Bentley steering worm. | 28th May 1934 | Box 86 \ 4 scan0091 | |
| Graph detailing the performance of an Acme thread lubrication scheme for a Bentley steering worm at different temperatures and speeds. | 28th May 1934 | Box 86 \ 4 scan0092 | |
| Graph from 'Acme Thread' lubrication tests on a Bentley steering worm, plotting delivery against shaft speed and pressure at different temperatures. | 28th May 1934 | Box 86 \ 4 scan0093 | |
| Urgent internal request for modifications to a test bed gearbox for servo tests. | 15th Jun 1934 | Box 86 \ 4 scan0094 | |
| Solution for gearbox sleeve rattles in a Bentley by adding locating plungers. | 18th Jun 1934 | Box 86 \ 4 scan0095 | |
| Rectifying Bentley gearbox sleeve rattles by modifying the locating plungers and grooves. | 19th Jun 1934 | Box 86 \ 4 scan0096 | |
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