| Description | Date | Identifier | |
| Performance graph comparing engine output based on different valve sizes, camshaft timings, and carburettor setups. | 24th Jun 1932 | Box 102 \ 5 scan0136 | |
| Graph showing the effect of increased valve lift on a standard camshaft and cylinder head. | 24th Jun 1932 | Box 102 \ 5 scan0137 | |
| Power curve graph for the 7983 c.c. 8-litre Bentley engine, comparing Bentley and R.R. timing. | 24th Jun 1932 | Box 102 \ 5 scan0138 | |
| Performance comparison chart of an 8 Litre Bentley and a 40/50 R.R.M. engine, showing valve timing and B.M.E.P. | 24th Jun 1932 | Box 102 \ 5 scan0139 | |
| Performance graph and valve timing diagrams for an E57177 camshaft on a 20/25 HP engine. | 24th Jun 1932 | Box 102 \ 5 scan0140 | |
| Tabulated list comparing valve opening specifications for various engines. | 10th Oct 1932 | Box 102 \ 5 scan0141 | |
| The design and performance of reduced toe camshafts for the J.III & China engines, including ideal timing diagrams. | 10th Oct 1932 | Box 102 \ 5 scan0142 | |
| Improving engine power output and speed by modifying camshaft timings and design for the J.1 and Phantom II models. | 10th Oct 1932 | Box 102 \ 5 scan0143 | |
| Performance graph and timing diagrams for the E57177 (112°) camshaft. | 10th Oct 1932 | Box 102 \ 5 scan0144 | |
| Graph comparing Brake Mean Effective Pressure (B.M.E.P.) against engine speed (R.P.M.) for two different tappet clearance settings. | 10th Oct 1932 | Box 102 \ 5 scan0145 | |
| Performance graph comparing a 110.5° camshaft and a 120° camshaft with different tappet clearances. | 13th Dec 1932 | Box 102 \ 5 scan0146 | |
| Outlining the handover schedule and development status for the Large Bore J.3 engine unit and its associated components. | 13th Dec 1932 | Box 102 \ 5 scan0147 | |
| Optimal timing for a new camshaft, part number E.82448 1140, including a timing diagram. | 13th Dec 1932 | Box 102 \ 5 scan0148 | |
| The design of the petrol pump and operating mechanism for the J.1. engine. | 24th Dec 1932 | Box 102 \ 5 scan0149 | |
| Estimate for a camshaft balancing scheme for the 20/25-HP model. | 18th Nov 1933 | Box 102 \ 5 scan0150 | |
| Issues with valve gear noise and potential solutions involving tappet adjustment and camshaft design. | 11th Dec 1933 | Box 102 \ 5 scan0151 | |
| Investigation into the source of Bentley tappet noise and the ineffectiveness of insulating the rocker cover to reduce it. | 11th Dec 1933 | Box 102 \ 5 scan0152 | |
| Analysis of valve and cam noise, comparing materials and measuring cam contours to determine quiet operating velocities. | 11th Dec 1935 | Box 102 \ 5 scan0153 | |
| Technical analysis of cam contours, clearances, and their effects on tappet noise and valve velocity. | 11th Dec 1933 | Box 102 \ 5 scan0154 | |
| Data table specifying maximum clearances and velocities for quiet cam operation. | 11th Dec 1933 | Box 102 \ 5 scan0155 | |
| Graph showing valve lift against crankshaft degrees for a Bentley cam toe. | 11th Dec 1933 | Box 102 \ 5 scan0156 | |
| Blueprint graph showing Bentley Cam Toes performance, plotting valve lift against crankshaft degrees for an exhaust cam. | 11th Dec 1933 | Box 102 \ 5 scan0157 | |
| Graph plotting valve lift against crankshaft degrees for a Bentley B7 Unit No. 2 Cylinder Inlet Cam. | 11th Dec 1933 | Box 102 \ 5 scan0158 | |
| Blueprint graph comparing the valve lift of two different Bentley exhaust cam toe designs against crankshaft degrees. | 12th Feb 1937 | Box 102 \ 5 scan0159 | |
| Graph showing Bentley cam base circle contours for Unit B7. | 12th Feb 1937 | Box 102 \ 5 scan0160 | |
| Graph of Bentley cam toe profiles, comparing valve lift and velocity for standard and suggested designs. | 14th Oct 1938 | Box 102 \ 5 scan0161 | |
| Standardisation of a balancing cam on the camshaft to cure timing gear rattles. | 2nd Nov 1933 | Box 102 \ 5 scan0162 | |
| Notification regarding the breakage of tappet springs on Bentley & 20/25 models. | 30th Jun 1934 | Box 102 \ 5 scan0163 | |
| Modifications to Balancing Cam for lubrication, hardened camshaft end play washers, and improved crankcase webbing. | 27th Apr 1934 | Box 102 \ 5 scan0164 | |
| Estimated cost for extra jigs, tools, and equipment for the 'F.2' series. | 5th Jun 1934 | Box 102 \ 5 scan0165 | |
| Comparison graph of Brake Mean Effective Pressure (B.M.E.P.) curves for Cadillac and Rolls-Royce products. | 13th May 1935 | Box 102 \ 5 scan0166 | |
| Request to manufacture a 25 HP camshaft with specific timing for slow running experiments. | 13th May 1935 | Box 102 \ 5 scan0167 | |
| Design flaw, a twist, in the 20 HP Bonnet and proposing a wooden scale model for review. | 27th May 1919 | Box 102 \ 6 scan0001 | |
| Design and modifications for the 20 HP bonnet and radiator, requesting a wooden model and prints. | 13th Jun 1919 | Box 102 \ 6 scan0002 | |
| Requesting alterations to the blueprint LeC.1104 for the 20 HP Bonnet & Radiator. | 28th Oct 1919 | Box 102 \ 6 scan0003 | |
| Drawing LeC.1198 for the 'Goshawk' water suction pipe and related chassis modifications. | 14th Feb 1920 | Box 102 \ 6 scan0004 | |
| Modifications to the 'Goshawk' Bonnet to accommodate an enlarged radiator and adjust the hinges. | 3rd Nov 1920 | Box 102 \ 6 scan0005 | |
| Proposed radiator and bonnet design for the Goshawk II engine. | 20th Jan 1921 | Box 102 \ 6 scan0006 | |
| Drawings for the Goshawk 11 bonnet and top radiator support, noting outstanding design decisions. | 1st Jun 1921 | Box 102 \ 6 scan0007 | |
| 'Goshawk II' bonnet catch and associated drawing No. LeC.1403. | 9th Jun 1921 | Box 102 \ 6 scan0008 | |
| Design and placement instructions for the 'Goshawk II' bonnet catch. | 1st Jun 1921 | Box 102 \ 6 scan0009 | |
| Modifications to the Goshawk model's bonnet and radiator to differentiate it from the 40/50 model. | 2nd Jun 1922 | Box 102 \ 6 scan0010 | |
| Design alterations and compromises for the Goshawk bonnet, including radiator height and the fitting of louvres. | 9th Jun 1922 | Box 102 \ 6 scan0011 | |
| Proposed dimensional changes for the Goshawk bonnet and radiator, referencing drawing No. LeC.1595. | 16th Jun 1922 | Box 102 \ 6 scan0012 | |
| Modifications to a 3-Goshawk-11 limousine and its resemblance to the 40/50 model. | 19th Jun 1922 | Box 102 \ 6 scan0013 | |
| Mr. Royce's request to test a Goshawk limousine with a new dummy radiator and bonnet. | 20th Jun 1923 | Box 102 \ 6 scan0014 | |
| Selection and fitting of bonnet fastener springs for the 'Goshawk II'. | 12th Jul 1922 | Box 102 \ 6 scan0015 | |
| The policy for fitting thick leaf rear springs to new and existing cars. | 10th Aug 1922 | Box 102 \ 6 scan0016 | |
| Rust prevention treatments for the angle iron bonnet rest and mild steel brackets on the Goshawk-11 chassis. | 15th Sep 1922 | Box 102 \ 6 scan0017 | |
| Expecting the delivery of designs for a Generator Drive Brake and a Bonnet Fastener. | 11th Nov 1922 | Box 102 \ 6 scan0018 | |
| Standardisation of 'Goshawk II' lifting handles for the 40/50 chassis bonnet and their potential use on the 'R' Series. | 21th Nov 1922 | Box 102 \ 6 scan0019 | |
| From 'Hs' about tests on the Goshawk Bonnet, concluding that shutters are preferable to louvres for ventilation. | 23th Jan 1923 | Box 102 \ 6 scan0020 | |
| Adding louvres to the Goshawk and 40/50 bonnets to improve radiator cooling. | 23th Jan 1923 | Box 102 \ 6 scan0021 | |
| Issues with the top gear slipping out and bonnet fit, attributing the gear issue to faulty workmanship. | 26th Mar 1923 | Box 102 \ 6 scan0022 | |
| Car's water boiling during testing and questioning if this is expected behavior. | 23th Jul 1923 | Box 102 \ 6 scan0023 | |
| Requesting further information about a 20 HP engine overheating issue. | 26th Jul 1923 | Box 102 \ 6 scan0024 | |
| Faults found during a 10,000-mile test on a 20 HP production chassis, specifically a sticking air valve and bonnet fitting issues. | 27th Jul 1923 | Box 102 \ 6 scan0025 | |
| Follow-up memo arranging a reply regarding the 20-HP Chassis Louvres. | 18th Oct 1923 | Box 102 \ 6 scan0026 | |
| Standardisation of the screw fixing for bonnet strips on 20HP and 40/50HP chassis. | 24th Sep 1923 | Box 102 \ 6 scan0027 | |
| Proposal to fit sliding panels to the bonnet of a 20 HP car to address overheating issues. | 22th Jul 1924 | Box 102 \ 6 scan0028 | |
| Modifications to bonnet louvres, referencing Mr. Royce's preferences and Hispano designs. | 14th Jul 1925 | Box 102 \ 6 scan0029 | |
| Abandonment of a new bonnet clip design for Mr. Royce's car. | 14th Aug 1925 | Box 102 \ 6 scan0030 | |
| Seeking clarification on the design of louvred bonnets. | 28th Sep 1925 | Box 102 \ 6 scan0031 | |
| Technical memo discussing the design and pressing of louvres directly into the bonnet sheet. | 29th Sep 1925 | Box 102 \ 6 scan0032 | |
| Fitting the same type of louvres on the 20 HP bonnet as used on the 40/50 HP. | 18th Mar 1926 | Box 102 \ 6 scan0033 | |
| Sending a new louvred bonnet for a 20 HP model to London for evaluation and standardisation. | 12th Apr 1926 | Box 102 \ 6 scan0034 | |
| Standardisation of the louvered bonnet for the 20 HP model. | 29th Apr 1926 | Box 102 \ 6 scan0035 | |
| Standardisation document for modified louvres for the bonnet to improve appearance. | 12th Apr 1926 | Box 102 \ 6 scan0036 | |
| Modifications and standardisation of bonnet louvres for the 20-HP chassis. | 13th Jul 1926 | Box 102 \ 6 scan0037 | |
| Design for a 20 HP louvered bonnet with shorter louvres at the top. | 8th May 1926 | Box 102 \ 6 scan0038 | |
| History of bonnet catch springs for 20HP and 40/50HP chassis, seeking final approval for production. | 16th Jul 1926 | Box 102 \ 6 scan0039 | |
| Progress request regarding modified louvres to the bonnet for a 20 HP chassis. | 4th Aug 1926 | Box 102 \ 6 scan0040 | |
| Modified louvres for the bonnet of a 20 HP chassis. | 9th Aug 1926 | Box 102 \ 6 scan0041 | |
| Test report memo detailing issues found with a High Compression 20 HP car. | 1st Aug 1926 | Box 102 \ 6 scan0042 | |
| The delayed arrival of a new 20 HP louvred bonnet for inspection. | 3rd Nov 1926 | Box 102 \ 6 scan0043 | |
| Sending a 20 HP car with modified bonnet louvres for inspection and to deliver parts for Mr. Royce's car. | 8th Nov 1926 | Box 102 \ 6 scan0044 | |
| Sending a 20 HP car, model 11-G-111, to London with a modified louvred bonnet. | 10th Nov 1926 | Box 102 \ 6 scan0045 | |
| The superior appearance of shorter nearside louvres on the 20 HP car. | 12th Nov 1926 | Box 102 \ 6 scan0046 | |
| Improved appearance and standardization of louvres on bonnets. | 17th Nov 1926 | Box 102 \ 6 scan0047 | |
| Improvements to the Phantom throttle control and a proposal for standardising reduced-height bonnet louvres for the 20 HP car. | 18th Nov 1926 | Box 102 \ 6 scan0048 | |
| Standardisation of louvres in the bonnet to improve appearance. | 18th Nov 1926 | Box 102 \ 6 scan0049 | |
| The standardisation sheet for louvres in the bonnet of the 20 HP model. | 29th Nov 1926 | Box 102 \ 6 scan0050 | |
| Aesthetic design of radiators, bonnets, and frame height for cars. | 22th Dec 1926 | Box 102 \ 6 scan0051 | |
| Bonnet dimensions and the condemnation of a new radiator design due to its appearance. | 31th Dec 1926 | Box 102 \ 6 scan0052 | |
| Blueprint detailing the dimensions for four different bonnet series. | 30th Dec 1926 | Box 102 \ 6 scan0053 | |
| Design and improvement of bonnet fittings, clips, and locks for various car models. | 2nd Jan 1927 | Box 102 \ 6 scan0054 | |
| New bonnet lock schemes and lock barrel design for 40/50 and 20 HP models. | 1st Mar 1927 | Box 102 \ 6 scan0055 | |
| Design details of gear wheels, pins, and new bonnet fasteners, with references to sketches. | 6th Jan 1927 | Box 102 \ 6 scan0056 | |
| Design improvements for bonnet clips and overall bonnet aesthetics and dimensions. | 6th Jan 1927 | Box 102 \ 6 scan0057 | |
| Correcting a measurement for the 40/50 HP Bonnet and discussing appearance improvements. | 1st Nov 1927 | Box 102 \ 6 scan0058 | |
| Trial of a new bonnet lock and fastener design. | 22th Mar 1927 | Box 102 \ 6 scan0059 | |
| Deletion of rear shutters and bonnet louvres on Phantom & Goshawk models. | 1st Jul 1927 | Box 102 \ 6 scan0060 | |
| Modifications to the Phantom bonnet catch and a query on the 20 HP model. | 10th Sep 1927 | Box 102 \ 6 scan0061 | |
| Standardisation of chassis parts relating to a wider dashboard and bonnet to improve coachwork. | 10th Nov 1927 | Box 102 \ 6 scan0062 | |
| Standardisation form for chassis parts detailing testing and associated costs. | 19th Oct 1928 | Box 102 \ 6 scan0063 | |
| The failure of rivets on 20 HP Bonnet Side Strips, suggesting using larger and more rivets in the future. | 3rd May 1928 | Box 102 \ 6 scan0064 | |
| Alteration to increase the size and number of rivets on 20-HP bonnet side strips. | 7th May 1928 | Box 102 \ 6 scan0065 | |
| Standardisation of new dimensions for the 20.HP bonnet, radiator, and dash, following a proposal to Mr. Royce. | 15th May 1928 | Box 102 \ 6 scan0066 | |
| Standardisation of an improved appearance for the 20 HP model, including the bonnet, radiator and dash. | 19th May 1928 | Box 102 \ 6 scan0067 | |
| Modifications to the 20 HP improved bonnet, dash, and radiator. | 23th May 1928 | Box 102 \ 6 scan0068 | |
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