| Description | Date | Identifier | |
| Letter from F.M. Aspin & Co. Ltd. to W. A. Robotham regarding a 6-cylinder engine and research into 2 and 4-cycle engines. | 11th May 1940 | Box 134 \ 1 scan0237 | |
| Letter from F.M. Aspin & Co. Ltd. regarding the fitting of an 'Aspin' cylinder head. | 7th May 1940 | Box 134 \ 1 scan0238 | |
| Proposal for testing the Aspin valve for reliability and antidetonating qualities on a Bentley engine. | 1st May 1940 | Box 134 \ 1 scan0239 | |
| Sending a B.23 O.H.C. conversion unit to Messrs Aspin for conversion to their rotary valve design. | 30th Apr 1940 | Box 134 \ 1 scan0240 | |
| Letter detailing the proposal to use a 4.25 litre Bentley engine for research on a new valve application. | 27th Apr 1940 | Box 134 \ 1 scan0241 | |
| Outlining general conclusions from a discussion about the design of a single-cylinder engine unit and its adaptation for an Aspin cylinder head. | 23th Apr 1940 | Box 134 \ 1 scan0242 | |
| Page 2 of a design specification memo discussing auxiliary pumps and a standard single-cylinder unit. | 23th Apr 1940 | Box 134 \ 1 scan0243 | |
| Letter concerning single-cylinder tests and development work on the Aspin engine. | 19th Apr 1940 | Box 134 \ 1 scan0244 | |
| Letter from F. M. Aspin & Co. Ltd. discussing a delay in providing valve area figures and arranging a visit. | 18th Apr 1940 | Box 134 \ 1 scan0245 | |
| Letter to F.M. Aspin regarding the Aspin engine, rotary valve development, and single cylinder units. | 15th Apr 1940 | Box 134 \ 1 scan0246 | |
| Letter from F.M. Aspin & Co. Ltd. to W.A. Robotham discussing engine performance, fuel specifications, and compression ratios. | 6th Apr 1940 | Box 134 \ 1 scan0247 | |
| Letter detailing engine compression pressures, testing apparatus, and various valve timing specifications. | 6th Apr 1940 | Box 134 \ 1 scan0248 | |
| Continuation of a letter from F. M. Aspin & Co. Ltd. discussing gas engine test results and fuel consumption. | 6th Apr 1940 | Box 134 \ 1 scan0249 | |
| Performance tuning, detonation issues, and proposed modifications for a high power cylinder head. | 7th Jan 1935 | Box 134 \ 2 scan0001 | |
| Test results and further development of a high power cylinder head. | 7th Jan 1935 | Box 134 \ 2 scan0002 | |
| Results of a high power cylinder head and proposing new designs to improve flow and reduce detonation. | 8th Jan 1935 | Box 134 \ 2 scan0003 | |
| Development and testing of a high power single cylinder head. | 19th Mar 1935 | Box 134 \ 2 scan0004 | |
| Technical paper discussing combustion roughness in side-valve engines, focusing on detonation, pressure rise, and flame front characteristics. | 19th Mar 1935 | Box 134 \ 2 scan0005 | |
| The design and performance of different cylinder heads and combustion chambers. | 19th Mar 1935 | Box 134 \ 2 scan0006 | |
| Comparison of inlet valve to piston area ratios for various eight-cylinder high power engine heads. | 11th May 1935 | Box 134 \ 2 scan0007 | |
| Technical memorandum discussing engine design considerations for cylinder grouping, camshafts, and valve tappets. | 11th May 1935 | Box 134 \ 2 scan0008 | |
| Technical considerations for a 4.5 litre, 8-cylinder engine, comparing different configurations and materials. | 11th May 1935 | Box 134 \ 2 scan0009 | |
| Optimal angle and placement of a spark plug for improved engine performance. | 11th May 1935 | Box 134 \ 2 scan0010 | |
| Comparing inlet valve to piston area ratios across various engine cylinder heads. | 26th Apr 1935 | Box 134 \ 2 scan0011 | |
| Limitations and alternatives for cylinder head designs, including pent-house and ramp heads. | 26th Apr 1935 | Box 134 \ 2 scan0012 | |
| Experimental department report on a High Power Head for a Bentley. | 27th May 1935 | Box 134 \ 2 scan0013 | |
| The development and performance of a single cylinder Bentley unit with a high power head. | 27th May 1935 | Box 134 \ 2 scan0014 | |
| Report comparing high power single and twin-inlet cylinder heads with a standard head, including a detailed table of specifications. | 27th May 1935 | Box 134 \ 2 scan0015 | |
| Technical analysis comparing a high-power cylinder head design with the standard Bentley head, focusing on power output and valve timing. | 27th May 1935 | Box 134 \ 2 scan0016 | |
| Valve timing and detonation characteristics for high-power heads compared to standard Bentley heads. | 27th May 1935 | Box 134 \ 2 scan0017 | |
| Analysis of engine detonation tests with various cylinder head, gasket, and valve modifications. | 27th May 1935 | Box 134 \ 2 scan0018 | |
| Analysis of engine performance relating to exhaust valves, ignition timing, pressure rise, and spark plug position. | 27th Jun 1935 | Box 134 \ 2 scan0019 | |
| Fuel consumption comparisons and mechanical failures including piston seizure, cracked valves, valve springs and push rods. | 27th May 1935 | Box 134 \ 2 scan0020 | |
| Future development plans for high-power cylinder heads. | 27th May 1935 | Box 134 \ 2 scan0021 | |
| Performance graph from Bentley single cylinder tests comparing the power output of different high-power cylinder heads. | 27th May 1935 | Box 134 \ 2 scan0022 | |
| Graph plotting power output results from Bentley single cylinder tests on a twin inlet high power head. | 23th Apr 1957 | Box 134 \ 2 scan0023 | |
| Graph showing power variation, B.M.E.P., and fuel consumption against R.P.M. for a Bentley single-cylinder engine test with different choke sizes. | 23th Apr 1957 | Box 134 \ 2 scan0024 | |
| Graph showing power variation with choke size for a single inlet high power head engine during Bentley single cylinder tests. | 23th Apr 1957 | Box 134 \ 2 scan0025 | |
| Graph showing power output results from Bentley single-cylinder engine tests comparing different configurations. | 23th Apr 1957 | Box 134 \ 2 scan0026 | |
| Graph comparing power output, BMEP, and fuel consumption with an open exhaust versus a fitted car silencer during single-cylinder engine tests. | 23th Apr 1957 | Box 134 \ 2 scan0027 | |
| Graph comparing power and BMEP against RPM for short duration versus normal Bentley valve timings on a single cylinder engine. | 23th Apr 1957 | Box 134 \ 2 scan0028 | |
| Performance graph from Bentley single-cylinder engine tests, charting detonation and BMEP against RPM for a twin-inlet high-power head. | 23th Apr 1957 | Box 134 \ 2 scan0029 | |
| Graph plotting the results of detonation tests on a single inlet high power cylinder head with various configurations. | 23th Mar 1938 | Box 134 \ 2 scan0030 | |
| Graph plotting the results of Bentley single-cylinder detonation tests, showing the effect of a sodium-cooled exhaust valve. | 23th Mar 1938 | Box 134 \ 2 scan0031 | |
| Graph showing detonation tests comparing different types of inlet valves. | 23th Mar 1938 | Box 134 \ 2 scan0032 | |
| Blueprint graph showing ignition advance curves for high power heads during Bentley single cylinder tests. | 23th Apr 1957 | Box 134 \ 2 scan0033 | |
| Indicator diagram plotting cylinder pressure against crank angle for a single-cylinder test. | 23th Apr 1957 | Box 134 \ 2 scan0034 | |
| Report comparing engine head and valve arrangements, including sleeve valves and a 24-cylinder engine design. | 31th May 1935 | Box 134 \ 2 scan0035 | |
| The measurement and comparison of engine breathing capacity. | 30th May 1935 | Box 134 \ 2 scan0036 | |
| Comparison of Pegasus and Kestrel engine performance focusing on valve timing and port contours. | 30th May 1935 | Box 134 \ 2 scan0037 | |
| Analysis of engine performance focusing on exhaust valving and comparing Bentley and Kestrel Ramp head designs. | 30th May 1935 | Box 134 \ 2 scan0038 | |
| Comparison of sleeve valve and poppet valve engines, with a discussion on steel penthouse heads. | 30th May 1935 | Box 134 \ 2 scan0039 | |
| Technical comparison of various engine cylinder head designs, including Ramp, Penthouse, Kestrel, and Bentley types. | 30th May 1935 | Box 134 \ 2 scan0040 | |
| Comparative table of various engine specifications, including cylinder head types, dimensions, port areas, mean effective pressures, and RPM. | 18th Jul 1935 | Box 134 \ 2 scan0041 | |
| Value and continuation of single-cylinder research work on car engines. | 18th Jul 1935 | Box 134 \ 2 scan0042 | |
| Specification table outlining the ideal requirements for valve gear and combustion chamber design. | 18th Jul 1935 | Box 134 \ 2 scan0043 | |
| Review and opinion on the potential of a high-power cylinder head design compared to alternatives. | 18th Jul 1935 | Box 134 \ 2 scan0044 | |
| Report discussing the merits and drawbacks of Sleeve Valve and Overhead Camshaft engine designs for an in-line car. | 18th Jul 1935 | Box 134 \ 2 scan0045 | |
| The merits and drawbacks of an overhead camshaft engine design compared to existing push-rod engines. | 18th Jul 1935 | Box 134 \ 2 scan0046 | |
| The development and merits of side valve engines compared to overhead valve engines, referencing American automotive trends. | 18th Jul 1935 | Box 134 \ 2 scan0047 | |
| High power engine head design, focusing on valving, power output, and valve gear configuration. | 15th Jul 1935 | Box 134 \ 2 scan0048 | |
| Engine size comparisons and potential performance issues for 6 and 8-cylinder engines. | 15th Jul 1935 | Box 134 \ 2 scan0049 | |
| Blueprint comparing the lengths of 6-cylinder and 8-cylinder high power head engines. | 7th Aug 1935 | Box 134 \ 2 scan0050 | |
| Experimental department report concerning air flow through inlet valves. | 31th Oct 1935 | Box 134 \ 2 scan0051 | |
| Blowing tests to determine the effect of port shape on airflow through inlet valves. | 30th Oct 1935 | Box 134 \ 2 scan0052 | |
| Valve lift coefficients and port shape effects for Kestrel, Merlin, and car size cylinders. | 30th Oct 1935 | Box 134 \ 2 scan0053 | |
| Comparative analysis table of various engine cylinder heads with performance metrics and a brief conclusion. | 30th Oct 1935 | Box 134 \ 2 scan0054 | |
| Analysis of how pressure drop at engine inlet valves reduces power. | 30th Oct 1935 | Box 134 \ 2 scan0055 | |
| The ramming effect in induction systems, detailing volumetric efficiency and power increases on the Kestrel cylinder. | 30th Oct 1935 | Box 134 \ 2 scan0056 | |
| Graph of Inlet Valve Discharge Coefficients showing the variation with valve diameter at a constant lift of 0.2 inches. | 2nd Sep 1935 | Box 134 \ 2 scan0057 | |
| Graph of inlet valve discharge coefficients versus valve lift for Kestrel size cylinders on an air blowing rig. | 2nd Sep 1935 | Box 134 \ 2 scan0058 | |
| Graph of inlet valve discharge coefficients for PV12 size cylinders on an air blowing rig. | 2nd Sep 1935 | Box 134 \ 2 scan0059 | |
| Graph of inlet valve discharge coefficients versus valve lift for car size cylinders on an air blowing rig. | 2nd Sep 1935 | Box 134 \ 2 scan0060 | |
| Summary of performance characteristics for a high-power cylinder head, detailing power gains, detonation issues, and smoothness. | 1st Jul 1936 | Box 134 \ 2 scan0061 | |
| Design analysis of a Chevrolet-style cylinder head and a High Power Main Engine, discussing combustion, valving, and valve gear. | 15th Jul 1935 | Box 134 \ 2 scan0062 | |
| Engine head modifications to cure detonation, considering valve types, head angles, and materials. | 15th Jul 1935 | Box 134 \ 2 scan0063 | |
| Comparison of M.E.P. gains and power gains between various Bentley engine cylinder heads at different RPMs. | 15th Jul 1935 | Box 134 \ 2 scan0064 | |
| Concluding summary on the practical difficulties and future research related to incorporating a twin inlet valve head in an engine. | 11th Jul 1936 | Box 134 \ 2 scan0065 | |
| Blueprint graph of smoothness curves and flame travel analysis for a turbulent high power head. | 11th Jul 1936 | Box 134 \ 2 scan0066 | |
| Comparison of 'High Power' and 'Chevrolet' cylinder heads, showing valve sizes and cross-sectional diagrams. | 11th Jul 1938 | Box 134 \ 2 scan0067 | |
| Graph comparing the power output and B.M.E.P. of different High Power Bentley cylinder heads. | 10th Jul 1936 | Box 134 \ 2 scan0068 | |
| Graph comparing the performance of a single-cylinder unit against a main engine. | 10th Jul 1936 | Box 134 \ 2 scan0069 | |
| Merits and demerits of single-cylinder engine work versus full-scale testing for future engine design. | 1st Sep 1936 | Box 134 \ 2 scan0070 | |
| Engine power output, weight, and reliability for 6-cylinder power units. | 1st Sep 1936 | Box 134 \ 2 scan0071 | |
| Technical memorandum discussing the comparative merits of engine designs regarding cost, silence, smoothness, and slow running. | 1st Sep 1936 | Box 134 \ 2 scan0072 | |
| Analysis of the disadvantages of side valve exhaust engine construction and consideration of future engine designs. | 1st Sep 1936 | Box 134 \ 2 scan0073 | |
| Summary comparing the existing push-rod overhead valve engine with a proposed 6-cylinder overhead camshaft design for future chassis. | 1st Sep 1936 | Box 134 \ 2 scan0074 | |
| Performance graph detailing the cylinder head development for a 4 1/4 Litre Bentley engine. | 1st Sep 1936 | Box 134 \ 2 scan0075 | |
| Development of a high power single-cylinder head, including part modifications and new instructions. | 1st Sep 1936 | Box 134 \ 2 scan0076 | |
| Failed exhaust valve on a Phantom III cylinder head and the supply of prints for a modified replacement. | 2nd Sep 1936 | Box 134 \ 2 scan0077 | |
| Modified sparking plug inclination for a single-cylinder, high-power head. | 5th Sep 1936 | Box 134 \ 2 scan0078 | |
| Future car engine design, focusing on single-cylinder development work. | 3rd Oct 1936 | Box 134 \ 2 scan0079 | |
| Engine cylinder head design, detonation issues, and potential improvements including valve and camshaft design. | 3rd Oct 1936 | Box 134 \ 2 scan0080 | |
| Page discussing the testing of a high-power head, dry liner aluminium block, and combustion chamber development. | 15th Oct 1936 | Box 134 \ 2 scan0081 | |
| Details for manufacturing a High Power Single Inlet Valve Head in aluminium instead of cast iron. | 15th Oct 1936 | Box 134 \ 2 scan0082 | |
| Machining of a spare cylinder block and the provision of prints for exhaust valves. | 9th Oct 1936 | Box 134 \ 2 scan0083 | |
| Request to complete a modified cylinder block for a high power head on a small universal unit. | 7th Oct 1936 | Box 134 \ 2 scan0084 | |
| Incorrect obsolete inlet valve springs being fitted to a high power cylinder head. | 16th Oct 1936 | Box 134 \ 2 scan0085 | |
| Aluminium cylinder block with a dry liner for a high power head, including modifications and attached prints. | 28th Oct 1936 | Box 134 \ 2 scan0086 | |
| Letter to Coventry Climax Engine Co. Ltd. proposing a discussion about a single-cylinder research engine. | 19th Oct 1936 | Box 134 \ 2 scan0087 | |
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