| Description | Date | Identifier | |
| Sg. to Hs. requesting a status update regarding radiators. | 11th Apr 1931 | Box 149a \ 3 scan0078 | |
| Confirming a car will be sent to Brooklands for radiator tests. | 13th Apr 1931 | Box 149a \ 3 scan0079 | |
| Results of Phantom II radiator tests comparing different tube types. | 21th Apr 1931 | Box 149a \ 3 scan0080 | |
| Page two of a report on the efficiency of tube shapes, with a note on future testing. | 21th Apr 1931 | Box 149a \ 3 scan0081 | |
| Table comparing the cooling performance of different radiator tube types under various bonnet ventilation conditions. | 27th Mar 1930 | Box 149a \ 3 scan0082 | |
| Technical drawing for a 'Matrix Tube' detailing dimensions, materials, and testing procedures. | 27th Mar 1930 | Box 149a \ 3 scan0083 | |
| Sending two sample American tubes following a report on radiators. | 22th Apr 1931 | Box 149a \ 3 scan0084 | |
| Manufacture of copper radiator tubes and their waterway specifications. | 15th May 1931 | Box 149a \ 3 scan0085 | |
| Request to build a radiator for a 25-EX 10,000 miles test car by converting a radiator from a 19-EX model. | 20th May 1931 | Box 149a \ 3 scan0086 | |
| Experimental order of radiator tubes for the 40/50 HP and 20/25 HP models. | 27th May 1931 | Box 149a \ 3 scan0087 | |
| Customer overheating complaints and proposed changes to radiator design, including tube size and bonnet ventilation. | 28th May 1931 | Box 149a \ 3 scan0088 | |
| Radiator overheating and boiling issues, and potential modifications to improve cooling efficiency. | 1st Jun 1931 | Box 149a \ 3 scan0089 | |
| Proposing the standardization of a small hexagon tube and new movable bonnet openings for weight reduction and improved safety. | 5th Jun 1931 | Box 149a \ 3 scan0090 | |
| Requesting views and recommendations on radiator tubes, referencing letters from the Winchester Repeating Arms Company. | 8th Jun 1931 | Box 149a \ 3 scan0091 | |
| Production of U.S.A. type radiator tubes in England. | 9th Jun 1931 | Box 149a \ 3 scan0092 | |
| Benefits and drawbacks of different radiator tube designs regarding cost, weight, and performance. | 12th Jun 1931 | Box 149a \ 3 scan0093 | |
| Comparative tests on different radiator tube sizes and bonnet cooling. | 18th Jul 1931 | Box 149a \ 3 scan0094 | |
| Building two new radiators for the 40/50 and 27-EX models using Kinoch made tubes. | 23th Jul 1931 | Box 149a \ 3 scan0095 | |
| Order for large diameter hexagon ended dented tubes for the new 25 HP radiator. | 29th Sep 1931 | Box 149a \ 3 scan0096 | |
| Visit to the Harrison Radiator Corporation in the USA. | 6th Feb 1934 | Box 149a \ 3 scan0097 | |
| Wind tunnel work, Viscon oil cooler development, and improvements to radiator core efficiency. | 6th Feb 1934 | Box 149a \ 3 scan0098 | |
| Harrison's developments in radiator and oil cooler technology, including tests and design specifics. | 6th Feb 1934 | Box 149a \ 3 scan0099 | |
| The design and performance of an oil cooler, including diagrams and heat transfer analysis. | 6th Feb 1934 | Box 149a \ 3 scan0100 | |
| Notes on engine cooling, comparing series water flow with other designs and discussing fan speeds and blade configurations. | 6th Feb 1934 | Box 149a \ 3 scan0101 | |
| Technical memo discussing cooling system designs and competitor analysis, including pulleys, fan blades, thermostats and cowls. | 6th Feb 1934 | Box 149a \ 3 scan0102 | |
| Competitor thermostat technology, research facilities, and future concepts for pressure steam-cooled engines. | 6th Feb 1934 | Box 149a \ 3 scan0103 | |
| Letter to the Harrison Radiator Corporation regarding the potential for manufacturing thermostats under license. | 24th May 1934 | Box 149a \ 3 scan0104 | |
| Letter to The Harrison Radiator Corporation requesting advice and a quote for a radiator matrix. | 4th Jun 1934 | Box 149a \ 3 scan0105 | |
| Sketch showing dimensions of a proposed 'Spectre' radiator. | 6th Jul 1934 | Box 149a \ 3 scan0106 | |
| Cover letter from Herbert Clark to W.A. Robotham regarding an enclosed letter from the Cuno Engineering Corporation. | 11th Jun 1934 | Box 149a \ 3 scan0107 | |
| Letter from The Cuno Engineering Corporation regarding the discontinuation of the Camel Radiator Control Valve. | 28th May 1934 | Box 149a \ 3 scan0108 | |
| Short letter to H. Clarke Esq. apologising that some people have packed up. | 16th Jun 1934 | Box 149a \ 3 scan0109 | |
| Follow-up letter from Illsley Company regarding a potential licensing agreement for their Closed Radiation system. | 12th Jun 1934 | Box 149a \ 3 scan0110 | |
| Cover letter to Bendix Limited concerning a mysterious letter received from the Illsley Co. | 25th Jun 1934 | Box 149a \ 3 scan0111 | |
| Letter to The Illsley Company in the U.S.A. regarding the potential licensing of their radiator valves in England. | 25th Jun 1934 | Box 149a \ 3 scan0112 | |
| Letter from General Motors Corporation regarding a license request. | 19th Jun 1934 | Box 149a \ 3 scan0113 | |
| Letter to Bendix Limited regarding the manufacture of thermostats, enclosing correspondence from Harrison Radiator Corporation. | 3rd Jul 1934 | Box 149a \ 3 scan0114 | |
| Letter from Harrison Radiator Corporation discussing the feasibility of producing a radiator core to a specified 3.3' depth. | 19th Jun 1934 | Box 149a \ 3 scan0115 | |
| Letter to the Harrison Radiator Corporation regarding the preferred dimensions of a new radiator matrix. | 9th Jul 1934 | Box 149a \ 3 scan0116 | |
| Request to order a specific radiator matrix from the Harrison Radiator Corporation. | 9th Jul 1934 | Box 149a \ 3 scan0117 | |
| Letter from Bendix Ltd enclosing a letter and blueprint received from the States. | 12th Jul 1934 | Box 149a \ 3 scan0118 | |
| Letter from Bendix Products Corp. discussing materials for thermostatic heat control and an experimental carburetter. | 15th Jun 1934 | Box 149a \ 3 scan0119 | |
| Letter to Messrs. Bendix Limited regarding the return of a blueprint. | 21th Jul 1934 | Box 149a \ 3 scan0120 | |
| Letter to Messrs. Bendix Ltd. enclosing a copy of correspondence from The Illsley Co., U.S.A. | 30th Jul 1934 | Box 149a \ 3 scan0121 | |
| Letter from Illsley Company discussing business issues and product problems with Cuno Company. | 18th Jul 1934 | Box 149a \ 3 scan0122 | |
| Page 2 of a business letter to Mr. Robotham regarding product adoption, market intelligence, and competitor activities. | 18th Jul 1934 | Box 149a \ 3 scan0123 | |
| Letter to H. Clark of Bendix Ltd. enclosing a copy of a letter from the Illsley Company, U.S.A. | 27th Aug 1934 | Box 149a \ 3 scan0124 | |
| Letter from Illsley Company to Mr. Robotham regarding positive customer feedback for their valves from Mr. Railton and Mr. S. C. H. Davis. | 1st Aug 1934 | Box 149a \ 3 scan0125 | |
| Letter from Harrison Division (General Motors) regarding the inability to currently produce a requested radiator. | 22th Aug 1934 | Box 149a \ 3 scan0126 | |
| Letter from Harrison Division (General Motors) confirming they will proceed to build a die and ship the core. | 23th Aug 1934 | Box 149a \ 3 scan0127 | |
| Telegram from Harrison Radiator Corporation confirming the completion and shipment of tools and a radiator. | 23th Aug 1934 | Box 149a \ 3 scan0128 | |
| Quoting a letter from Harrison Radiator Corporation about the production timeline for a special sample radiator core. | 15th Sep 1934 | Box 149a \ 3 scan0129 | |
| Quoting a letter from The Harrison Radiator Corporation regarding a radiator matrix sample core. | 15th Sep 1934 | Box 149a \ 3 scan0130 | |
| Inquiry from General Motors about a pressure relief valve similar to their 'Swank valve'. | 11th Sep 1934 | Box 149a \ 3 scan0131 | |
| Inquiry from a Mr. Saunders about an anti-spill radiator valve. | 20th Sep 1934 | Box 149a \ 3 scan0132 | |
| Letter to The Harrison Radiator Corporation regarding a query on radiator valves. | 22th Sep 1934 | Box 149a \ 3 scan0133 | |
| Requesting information to reply to an inquiry from Mr. Saunders of General Motors about an anti-spill radiator valve. | 20th Sep 1934 | Box 149a \ 3 scan0134 | |
| On the implementation and patent status of an anti-splash valve fitted to radiator filler caps. | 21th Feb 1934 | Box 149a \ 3 scan0135 | |
| Instruction and patenting of an anti-splash valve for radiators fitted to filler caps. | 21th Sep 1934 | Box 149a \ 3 scan0136 | |
| Letter from the Harrison Division of General Motors Corporation acknowledging a previous letter and enclosed information. | 5th Oct 1934 | Box 149a \ 3 scan0137 | |
| Report comparing an anti-spill radiator cap valve with a 'Camel' type valve. | 29th Nov 1934 | Box 149a \ 3 scan0138 | |
| Dissatisfaction with current anti-spill radiator caps and the testing of a superior American 'Camel' valve. | 29th Nov 1934 | Box 149a \ 3 scan0139 | |
| Letter from W.W. Constantine regarding Harrison Radiator Cores and a potential manufacturing license. | 14th Dec 1934 | Box 149a \ 3 scan0140 | |
| Letter to W.W. Constantine regarding the potential licensing and manufacture of Harrison Radiator Cores. | 17th Dec 1934 | Box 149a \ 3 scan0141 | |
| Letter to W.W. Constantine regarding the supply and potential manufacturing of Harrison Radiator Cores. | 17th Dec 1934 | Box 149a \ 3 scan0142 | |
| Anti-spill radiator cap valve, comparing it to a 'Camel' type and suggesting its use for the Spectre or Wraith models. | 31th Dec 1934 | Box 149a \ 3 scan0143 | |
| Letter from John Marston Limited regarding a meeting to discuss and examine the 'American Matrix'. | 3rd Jan 1935 | Box 149a \ 3 scan0144 | |
| Letter from a consulting engineer acknowledging receipt of a letter and a sample Marston bonded radiator matrix. | 7th Jan 1935 | Box 149a \ 3 scan0145 | |
| Letter from Illsley Company regarding a previous letter, product success, and new models. | 28th May 1935 | Box 149a \ 3 scan0146 | |
| Letter from Hudson Motor Car Company to Illsley Company regarding the performance of coolant control valves. | 2nd Jan 1935 | Box 149a \ 3 scan0147 | |
| Photographs comparing different types of thermostats and their components, including 'Type K', 'Type G', and 'Type B'. | 30th Jul 1935 | Box 149a \ 3 scan0148 | |
| Graph plotting water and air temperature against distance for a B-56-BN vehicle climbing the Stelvio Pass. | 30th Jul 1935 | Box 149a \ 3 scan0149 | |
| Letter to the Harrison Radiator Corporation regarding radiator matrix technologies and competitor products. | 26th Nov 1935 | Box 149a \ 3 scan0150 | |
| Letter from Harrison Radiator Corporation regarding radiator core comparisons and oil regulator issues. | 10th Dec 1935 | Box 149a \ 3 scan0151 | |
| Letter from a consulting engineer regarding the similarity of Marstons' radiator cores to a patented design, requesting a sample for inspection. | 18th Dec 1934 | Box 149a \ 3 scan0152 | |
| Letter from Harrison Radiator Corporation discussing radiator cooling, air consumption, and enclosed test results. | 6th Jan 1936 | Box 149a \ 3 scan0153 | |
| Letter to Harrison Radiator Corporation discussing comparative tests on Mark V and Mark VI radiator blocks. | 7th Jan 1935 | Box 149a \ 3 scan0154 | |
| Query regarding oil cooler failures and seeking advice on the best matrix design for maximum heat dissipation. | 7th Jan 1936 | Box 149a \ 3 scan0155 | |
| Letter from Harrison Radiator Corporation discussing radiator core performance and design. | 24th Jan 1936 | Box 149a \ 3 scan0156 | |
| Letter from Harrison Radiator Corporation concerning oil cooler difficulties and design modifications. | 24th Jan 1936 | Box 149a \ 3 scan0157 | |
| Letter to the Harrison Radiator Corporation about radiator test blocks, cooling curves, and requesting clarification on technical terms and test data. | 9th Mar 1936 | Box 149a \ 3 scan0158 | |
| Radiator core test results, different core types, and the strength of oil coolers. | 9th Mar 1936 | Box 149a \ 3 scan0159 | |
| Letter requesting comparative test figures for Gallay and Mark VI (20 x 99) types of block. | 9th Mar 1936 | Box 149a \ 3 scan0160 | |
| Letter from Harrison Radiator Corporation discussing the relative cooling performance and specifications of various radiator cores. | 9th Apr 1936 | Box 149a \ 3 scan0161 | |
| Page 2 of a letter from Harrison Radiator Corporation regarding a constant core design and oil cooler production. | 9th Apr 1936 | Box 149a \ 3 scan0162 | |
| Performance chart showing heat transfer versus air velocity for 20 x 55 x 2 1/8 AC.R.V. Cores with varying gap sizes. | 9th Apr 1936 | Box 149a \ 3 scan0163 | |
| Performance chart for A.C. R.V. cores, plotting heat transfer rate against air velocity for various gap sizes. | 9th Apr 1936 | Box 149a \ 3 scan0164 | |
| Diagram showing the dimensions and specifications for a 20 x 55 cell core. | 9th Sep 1936 | Box 149a \ 3 scan0165 | |
| Cover letter discussing radiator suppliers, specifically Modine Manufacturing Co., Marston, and Harrison. | 9th Sep 1936 | Box 149a \ 3 scan0166 | |
| Sales letter from Modine Manufacturing Company offering their radiator manufacturing services. | 28th Aug 1936 | Box 149a \ 3 scan0167 | |
| Letter to Harrison Radiator Corporation regarding the cooling systems of the Phantom III and Bentley cars, enclosing technical data. | 16th Jun 1936 | Box 149a \ 3 scan0168 | |
| Car engine cooling performance and seeking advice on remedying related issues. | 16th Jun 1936 | Box 149a \ 3 scan0169 | |
| Letter detailing cooling issues with the Phantom III car, including hot air escape from the bonnet and a discussion on oil coolers. | 16th Jun 1936 | Box 149a \ 3 scan0170 | |
| List of attached curves, figures, diagrams and drawings for various models including the Phantom III, Bentley and 20/25. | 16th Jun 1936 | Box 149a \ 3 scan0171 | |
| Data sheet listing critical air temperatures for Phantom III, Bentley, and 20/25 HP cars. | 16th Jun 1936 | Box 149a \ 3 scan0172 | |
| List of miscellaneous specifications for fan speed, matrix weights, and cooling system capacity. | 16th Jun 1936 | Box 149a \ 3 scan0173 | |
| Letter from Harrison Radiator Corporation comparing test results of Gallay, Harrison, and Chausson radiator cores. | 16th Jun 1936 | Box 149a \ 3 scan0174 | |
| Letter from Harrison Radiator Corporation discussing airflow characteristics of various radiator cores. | 16th Jun 1936 | Box 149a \ 3 scan0175 | |
| Letter from Harrison Radiator Corporation discussing radiator performance and cooling for the Phantom III and Bentley engines. | 18th Aug 1936 | Box 149a \ 3 scan0176 | |
| Letter from Harrison Radiator Corporation discussing vehicle cooling systems, critical air temperatures, and radiator design. | 18th Aug 1936 | Box 149a \ 3 scan0177 | |
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