| Description | Date | Identifier | |
| Test report on B.G. radio screened spark plugs for the Kestrel engine. | 1st Jul 1932 | Box 58 \ 2 Scan042 | |
| Conclusion of a test on spark plug erosion and insulation breakdown. | 1st Jul 1932 | Box 58 \ 2 Scan043 | |
| Photograph of an assembled and disassembled spark plug elbow connector. | 1st Jul 1932 | Box 58 \ 2 Scan044 | |
| The testing and performance of 14mm spark plugs in various vehicles. | 1st Jul 1932 | Box 58 \ 2 Scan045 | |
| Photographic print showing a top-down view of seven spark plugs in a row. | 1st Jul 1932 | Box 58 \ 2 Scan046 | |
| Photograph displaying seven different models of Lodge spark plugs. | 4th Jul 1932 | Box 58 \ 2 Scan047 | |
| Advantages of using 14 MM sparking plugs over the standard 18 MM plugs. | 4th Jul 1932 | Box 58 \ 2 Scan048 | |
| Series of tests to determine the optimal sparking plug gap to overcome engine misfiring. | 22th Jun 1932 | Box 58 \ 2 Scan049 | |
| Letter to La Bougie B.G. regarding the testing of their sparkling plugs on a Kestrel engine. | 15th Jul 1932 | Box 58 \ 2 Scan050 | |
| New Siemens sparking plugs made of aluminium oxide and their suitability for car engines. | 9th Dec 1932 | Box 58 \ 2 Scan051 | |
| Declining interest in Siemens sparking plugs in favour of the British made ones currently in use. | 12th Dec 1932 | Box 58 \ 2 Scan052 | |
| Siemens sparking plugs sent for technical evaluation, not as a substitute, with a request for their return. | 13th Dec 1932 | Box 58 \ 2 Scan053 | |
| The return of Siemens sparking plugs and related descriptive literature. | 15th Dec 1932 | Box 58 \ 2 Scan054 | |
| Despatch note for three Siemens Sparking Plugs to be sent to Col. Fell at Sales. | 15th Dec 1932 | Box 58 \ 2 Scan055 | |
| Acknowledging the receipt of literature and sample Siemens sparking plugs. | 16th Dec 1932 | Box 58 \ 2 Scan056 | |
| History, development, and testing of Wizard Sparking Plugs. | 2nd Oct 1933 | Box 58 \ 2 Scan057 | |
| Wizard sparking plug's performance with leaded versus undoped fuels and its high altitude limitations. | 2nd Oct 1933 | Box 58 \ 2 Scan058 | |
| Wizard sparking plugs, quoting a letter from the makers about Air Ministry approval and an inquiry for testing on a Buzzard engine. | 12th Oct 1933 | Box 58 \ 2 Scan059 | |
| Letter to the Air Ministry requesting clarification on sparking plug electrode erosion. | 24th Oct 1933 | Box 58 \ 2 Scan060 | |
| Letter to the Air Ministry chasing a reply to a previous correspondence. | 7th Nov 1933 | Box 58 \ 2 Scan061 | |
| Letter from the Air Ministry discussing the rate of erosion in low versus high voltage spark plug gaps. | 8th Nov 1933 | Box 58 \ 2 Scan062 | |
| Inquiry regarding a previous request concerning Wizard Sparking Plugs, Limited. | 8th Nov 1933 | Box 58 \ 2 Scan063 | |
| Correspondence regarding an agreement between Wizard Sparking Plugs Ltd. and K.L.G.Co. | 9th Nov 1933 | Box 58 \ 2 Scan064 | |
| Request to Mr. Jaques of the A.I.D. for a copy of the 'sparking plug test specification E.E.141'. | 21th Nov 1933 | Box 58 \ 2 Scan065 | |
| Letter to the Royal Aircraft Establishment regarding sparking plug testing and the effects of leaded fuel. | 13th Dec 1933 | Box 58 \ 2 Scan066 | |
| Letter discussing issues with CIS E12S B.T.H. Magnetos and the testing of Phosphor Bronze braided ignition cables. | 29th Dec 1933 | Box 58 \ 2 Scan067 | |
| Letter from the Royal Aircraft Establishment discussing sparking plug specifications and the effects of tetra-ethyl lead fuel. | 29th Dec 1933 | Box 58 \ 2 Scan068 | |
| Letter discussing the discolouration of mica insulation and ongoing flight tests of phosphor bronze braided ignition cable. | 20th Jan 1934 | Box 58 \ 2 Scan069 | |
| Transfer of various redundant sparking plugs to the A.M. Bond. | 20th Jan 1934 | Box 58 \ 2 Scan070 | |
| The disposal of redundant sparking plugs used for the Schneider Trophy R engine. | 20th Jan 1934 | Box 58 \ 2 Scan071 | |
| Request to obtain the patent specifications for B.G. sparking plugs. | 26th Jan 1934 | Box 58 \ 2 Scan072 | |
| Tests conducted on Siemens sparking plugs with 'Sinterkorund' ceramic insulators. | 3rd May 1934 | Box 58 \ 2 Scan073 | |
| The physical properties, construction, and leakage tests of Sinterkorund sparking plugs. | 3rd May 1934 | Box 58 \ 2 Scan074 | |
| Gas leakage and pre-ignition tests on various spark plugs. | 3rd May 1934 | Box 58 \ 2 Scan075 | |
| Pre-ignition limits and subsequent gas leakage tests on various spark plugs. | 3rd May 1934 | Box 58 \ 2 Scan076 | |
| Engine and temperature tests on 'Sinterkorund' insulated sparking plugs, including conclusions on performance and deterioration. | 3rd May 1934 | Box 58 \ 2 Scan077 | |
| Engine test and the properties of a ceramic material for aero plugs. | 1st Mar 1932 | Box 58 \ 2 Scan078 | |
| Report appendix comparing the properties of a new ceramic insulating material, 'Sinterkorund', for sparking plugs. | 1st Mar 1932 | Box 58 \ 2 Scan079 | |
| Diagram and specification sheet for a Siemens Sinterkorund Insulated Spark Plug, Type A.G. 30. | 15th Feb 1934 | Box 58 \ 2 Scan080 | |
| Cross-section diagram of a patented 'CF' spark plug. | 12th Nov 1931 | Box 58 \ 2 Scan081 | |
| Description of the C.F. spark plug, patented by Dott. Ing. A. Tebaldi. | 12th Nov 1931 | Box 58 \ 2 Scan082 | |
| In Italian describing the features and results of the C.F. spark plug. | 8th Mar 1934 | Box 58 \ 2 Scan083 | |
| Request to order a small vice for the sparking plug test bench. | 8th Mar 1934 | Box 58 \ 2 Scan084 | |
| Internal order request for a Record Vice for the Sparking Plug Test Bench. | 1st Mar 1934 | Box 58 \ 2 Scan085 | |
| Testing procedures for taper screwed sparking plug inserts in a Bentley aluminium cylinder head. | 23th Mar 1934 | Box 58 \ 2 Scan086 | |
| Report from tester Henniker regarding issues with sparking plug screens and exhaust pipes on a Short Monoplane R24/31. | 7th Apr 1934 | Box 58 \ 2 Scan087 | |
| Copy of a report from a tester regarding a delay in fitting new sparking plugs to a Short Monoplane R24/31. | 11th Apr 1934 | Box 58 \ 2 Scan088 | |
| The potential testing of miniature 10mm sparking plugs for cylinder design. | 23th Apr 1934 | Box 58 \ 2 Scan089 | |
| Letter to Messrs. Bosch Ltd. requesting a list of aero engine detachable spark plugs for testing purposes. | 27th Apr 1934 | Box 58 \ 2 Scan090 | |
| Letter from Bosch Limited clarifying the required thread size for aero sparking plugs. | 1st May 1934 | Box 58 \ 2 Scan091 | |
| Letter to Messrs. Bosch Ltd. clarifying sparking plug thread and reach specifications. | 2nd May 1934 | Box 58 \ 2 Scan092 | |
| Request to obtain a sample 18 m/m sparking plug from G.M.S. Plugs Limited. | 8th May 1934 | Box 58 \ 2 Scan093 | |
| Letter from Bosch Limited acknowledging a query about Aero Plugs. | 8th May 1934 | Box 58 \ 2 Scan094 | |
| Mechanical weakness of miniature sparking plugs smaller than 14mm. | 10th May 1934 | Box 58 \ 2 Scan095 | |
| Letter from G.M.S Plugs Ltd. regarding the supply of an 18 m.m. G.M.S. Plug for testing. | 10th May 1934 | Box 58 \ 2 Scan096 | |
| Ministry's instructions for the type testing of sparking plugs. | 31th May 1934 | Box 58 \ 2 Scan097 | |
| Translation of a patent description for C.F. Sparking Plugs by Dr. A. Tebaldi. | 31th May 1934 | Box 58 \ 2 Scan098 | |
| Description of a self-regulating C.F. sparking-plug, detailing its operation based on thermal expansion and its advantages. | 28th May 1934 | Box 58 \ 2 Scan099 | |
| Inquiry sent to Major Carington of K.L.G. Sparking Plugs regarding a novel Italian-made spark plug. | 28th May 1934 | Box 58 \ 2 Scan100 | |
| Letter from K.L.G. Sparking Plugs discussing various spark plug designs and requesting breakdown voltage test results. | 30th May 1934 | Box 58 \ 2 Scan101 | |
| Letter from K.L.G. Sparking Plugs regarding the development and upcoming samples of V.7/2 plugs. | 30th May 1934 | Box 58 \ 2 Scan102 | |
| Letter concerning the testing and comparison of different sparking plugs. | 31th May 1934 | Box 58 \ 2 Scan103 | |
| Requesting a copy of the R.D.E. Specification for sparking plug type-tests. | 1st Jun 1934 | Box 58 \ 2 Scan104 | |
| Specification and schedule of tests for 18 mm type sparking plugs for aero engines. | 1st Apr 1934 | Box 58 \ 2 Scan105 | |
| Specifications for aero engine sparking plugs, including bodies and gland nuts. | 1st Apr 1934 | Box 58 \ 2 Scan106 | |
| Specification for sparking plug components, markings, and testing procedures. | 1st Apr 1934 | Box 58 \ 2 Scan107 | |
| Specifications and testing procedures for spark plugs, including gap setting, mechanical tests, and gas leakage. | 1st Apr 1934 | Box 58 \ 2 Scan108 | |
| Specification and testing procedures for sparking plugs, covering electrical and engine tests. | 1st Apr 1934 | Box 58 \ 2 Scan109 | |
| Acceptance test procedures and requirements for subsequent production sparking plugs. | 1st Jun 1934 | Box 58 \ 2 Scan110 | |
| Letter from Bosch Limited responding to an enquiry about aero plugs and requesting further engine details. | 1st Jun 1934 | Box 58 \ 2 Scan111 | |
| Letter to Bosch Ltd. clarifying the specifications for detachable plugs, referencing a similar K.L.G. plug. | 2nd Jun 1934 | Box 58 \ 2 Scan112 | |
| Follow-up letter from Wilson & Moore (M/c.) Ltd. regarding a 'Chamber-Quartz' sparking plug. | 4th Jun 1924 | Box 58 \ 2 Scan113 | |
| Letter rejecting a sample sparking plug due to design flaws with its 'Quartz' insulator. | 7th Jun 1934 | Box 58 \ 2 Scan114 | |
| Attached letter about plugs. | 8th Jun 1934 | Box 58 \ 2 Scan115 | |
| Correspondence regarding flight investigations into spark plugs for Kestrel engines in Osprey aircraft. | 6th Jun 1934 | Box 58 \ 2 Scan116 | |
| Résumé of the development of various sparking plugs for new aero engines. | 8th Jun 1934 | Box 58 \ 2 Scan117 | |
| Spark plug options and testing for Goshawk, P.V.12, and Kestrel VI engines. | 8th Jun 1934 | Box 58 \ 2 Scan118 | |
| Letter from Wilson & Moore Ltd. responding to feedback on a sample Quartz-Chamber plug. | 11th Jun 1934 | Box 58 \ 2 Scan119 | |
| Request to arrange the return of a loaned Quartz Chamber sparking plug to Messrs. Wilson & Moore Ltd. | 12th Jun 1934 | Box 58 \ 2 Scan120 | |
| Asking for a decision regarding sparking plugs to circulate information to outside men. | 15th Jun 1934 | Box 58 \ 2 Scan121 | |
| Attached letter from Mr. Emtage about the V.9/1 plug. | 15th Jun 1934 | Box 58 \ 2 Scan122 | |
| Letter from the Air Ministry discussing alternative spark plugs for the Kestrel engine. | 11th Jun 1934 | Box 58 \ 2 Scan123 | |
| The correct type of sparking plugs for various Kestrel engines. | 19th Jun 1934 | Box 58 \ 2 Scan124 | |
| The suitability of K.L.G. V7/1 sparking plugs for Kestrel S engines and suggesting Lodge A2/2 plugs as an alternative. | 20th Jun 1934 | Box 58 \ 2 Scan125 | |
| Cover letter regarding a translated report on experiments conducted on a patented plug. | 20th Jun 1934 | Box 58 \ 2 Scan126 | |
| Translated letter from A. Tebaldi of Milan concerning thermodynamic tests on sparkling plugs and a vacuum pump coupling plan. | 14th Jun 1934 | Box 58 \ 2 Scan127 | |
| Tests carried out on C.F. sparking plug electrodes to determine the variation of the transmission coefficient. | 14th Jun 1934 | Box 58 \ 2 Scan128 | |
| Page 2 of a report detailing heat transfer calculations using a calorimeter. | 14th Jun 1934 | Box 58 \ 2 Scan129 | |
| Page 3 of a report detailing heat transfer and conductivity calculations for a calorimeter experiment. | 14th Jun 1934 | Box 58 \ 2 Scan130 | |
| Experiment measuring the coefficient of heat transmission through copper rods under varying pressures, including a formula and a graph of results. | 14th Jun 1934 | Box 58 \ 2 Scan131 | |
| Report page detailing the results of experiments on the heat transmission coefficients of sparking plugs. | 14th Jun 1934 | Box 58 \ 2 Scan132 | |
| Report from F.I.M.A.C. Milano on spark plug performance, detailing conductivity, temperature, and material deformation. | 14th Jun 1934 | Box 58 \ 2 Scan133 | |
| Page from a report by F.I.M.A.C. MILANO concerning temperature, spark, and wear. | 27th Jan 1932 | Box 58 \ 2 Scan134 | |
| Schematic of a calorimeter for measuring the heat transfer coefficient of a spark plug. | 27th Jan 1932 | Box 58 \ 2 Scan135 | |
| Diagram of a calorimeter used for measuring the coefficient of thermal transmission between two copper rods. | 27th Jan 1932 | Box 58 \ 2 Scan136 | |
| Letter from Bosch Limited regarding a request for a K.L.G. type 744 spark plug, asking for its required characteristics for engine testing. | 21th Jun 1934 | Box 58 \ 2 Scan137 | |
| Page 2 of a letter from a Bosch Limited Director regarding meeting requirements. | 21th Jun 1934 | Box 58 \ 2 Scan138 | |
| Clearance issue with Bentley ignition plugs fouling distributor leads and causing a potential short circuit. | 22th Jun 1934 | Box 58 \ 2 Scan139 | |
| Note arranging the supply of a set of sparking plugs to Moseley. | 22th Jun 1934 | Box 58 \ 2 Scan140 | |
| Letter to Bosch Ltd. discussing the difficulty of specifying suitable spark plug characteristics for engines. | 23th Jun 1934 | Box 58 \ 2 Scan141 | |
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