| Description | Date | Identifier | |
| Request to verify the suitability of various types of plugs for Merlin engines prior to flight tests. | 16th Oct 1935 | Box 58 \ 2 Scan242 | |
| Letter from the Air Ministry regarding the testing and development of sample sparking plugs with integral screening. | 16th Oct 1935 | Box 58 \ 2 Scan243 | |
| Inclusion of K.L.G. plugs in a signed contract with the Yugoslav Government. | 30th Oct 1935 | Box 58 \ 2 Scan244 | |
| Letter from the Air Ministry regarding two new types of screened sparking plugs, Lodge X.496 and Lodge X.506, being sent for suitability assessment. | 1st Nov 1935 | Box 58 \ 2 Scan245 | |
| Letter regarding the submission of spark plugs for testing and evaluation. | 7th Nov 1935 | Box 58 \ 2 Scan246 | |
| Letter from the Air Ministry concerning the suitability of two types of radio-screened spark plugs for the Merlin engine. | 1st Nov 1935 | Box 58 \ 2 Scan247 | |
| Request to arrange for a joiner to make three small wooden racks for a sparking plug service bench. | 8th Nov 1935 | Box 58 \ 2 Scan248 | |
| Request to order K.L.G. pressure testing apparatus for aero integral screened plug tests. | 8th Nov 1935 | Box 58 \ 2 Scan249 | |
| Request to obtain two dies for cleaning sparking plug threads. | 8th Nov 1935 | Box 58 \ 2 Scan250 | |
| Letter to the Air Ministry regarding the suitability of Lodge integral screened plugs for Kestrel and Merlin engines. | 8th Nov 1935 | Box 58 \ 2 Scan251 | |
| The unsuitability of type X.506 plugs for the E. engine, with details on electrical bench tests. | 8th Nov 1935 | Box 58 \ 2 Scan252 | |
| Letter from Rotax Limited requesting details of spark plugs used in aero engines for voltage testing purposes. | 8th Nov 1935 | Box 58 \ 2 Scan253 | |
| Letter detailing the results of aero sparking plug voltage tests for Merlin and Kestrel engines. | 11th Nov 1935 | Box 58 \ 2 Scan254 | |
| Internal order for K.L.G. Pressure Testing Apparatus for integral screened plug tests. | 1st Nov 1935 | Box 58 \ 2 Scan255 | |
| Letter from the Air Ministry querying the design specifications for radio screened plugs on Kestrel engines. | 12th Nov 1935 | Box 58 \ 2 Scan256 | |
| On agreed dimensions for Merlin engine sparking plugs. | 18th Nov 1935 | Box 58 \ 2 Scan257 | |
| Testing of B.G. plugs by the Dutch Air Command and a proposal for a new type. | 19th Nov 1935 | Box 58 \ 2 Scan258 | |
| The testing of B.G. plugs for Holland on Kestrel engines. | 20th Nov 1935 | Box 58 \ 2 Scan259 | |
| Invoice from La Bougie B.G. for 12 sample spark plugs with elbows and sleeves for demonstration. | 25th Nov 1935 | Box 58 \ 2 Scan260 | |
| Dispatch of a sample batch of 'B.G.' plugs for testing and a request for a report. | 28th Nov 1935 | Box 58 \ 2 Scan261 | |
| List of suitable sparking plugs for Kestrel, Buzzard, and Merlin engines. | 29th Nov 1935 | Box 58 \ 2 Scan262 | |
| Internal request to order two specific types of sparking plugs. | 3rd Dec 1935 | Box 58 \ 2 Scan263 | |
| Letter to Messrs. K.L.G. Sparking Plugs Ltd. requesting descriptive booklets for foreign buyers. | 6th Dec 1935 | Box 58 \ 2 Scan264 | |
| Letter to Imperial Airways requesting feedback on the 'Wizard' type sparking plug. | 7th Dec 1935 | Box 58 \ 2 Scan265 | |
| Letter from Imperial Airways concerning the performance and oiling issues of 'Wizard' spark plugs. | 9th Dec 1935 | Box 58 \ 2 Scan266 | |
| Letter from an Engineer Superintendent discussing sparking plug oiling and an experiment to diagnose the cause. | 9th Dec 1935 | Box 58 \ 2 Scan267 | |
| Request to prepare H.T. ignition cables with B.G. plugs for testing for the Dutch Air Ministry. | 10th Dec 1935 | Box 58 \ 2 Scan268 | |
| Letter discussing the performance and reliability of K.L.G. Wizard sparking plugs in aircraft engines. | 21th Dec 1935 | Box 58 \ 2 Scan269 | |
| The performance of 14 m.m. Wizard spark plugs in various aircraft engines. | 21th Dec 1935 | Box 58 \ 2 Scan270 | |
| The performance and testing of various spark plugs in high-duty aircraft engines. | 21th Dec 1935 | Box 58 \ 2 Scan271 | |
| Letter to A.J. Rowledge regarding the development of a new engine and the potential use of Wizard sparking plugs. | 21th Dec 1935 | Box 58 \ 2 Scan272 | |
| Letter to The Breeze Corporation Inc. inquiring about radio ignition shielding for aero engines. | 21th Dec 1935 | Box 58 \ 2 Scan273 | |
| Cancelling instructions for starter plugs and sockets for prototype Merlin engines. | 30th Dec 1935 | Box 58 \ 2 Scan274 | |
| The urgent need for flight tests on Lodge and K.L.G. sparking plugs for the Merlin engine. | 31th Dec 1935 | Box 58 \ 2 Scan275 | |
| The fitting and servicing of sparking plugs for the Merlin Engine in a Horsley aircraft. | 2nd Jan 1936 | Box 58 \ 2 Scan276 | |
| Request for one set of inlet plug ignition cables to be made for a Merlin E engine. | 10th Jan 1936 | Box 58 \ 2 Scan277 | |
| The change in finish for Bentley sparking plugs to cadmium plated. | 14th Jan 1936 | Box 58 \ 2 Scan278 | |
| Order for one dozen aero sparking plug setting gauges. | 16th Jan 1936 | Box 58 \ 2 Scan279 | |
| Modifications to the Merlin 'E' engine's sparking plug connections and housing, including blueprints. | 16th Jan 1936 | Box 58 \ 2 Scan280 | |
| Obtaining a new wireless plug for Chassis 32-EX. | 18th Jan 1936 | Box 58 \ 2 Scan281 | |
| Trouble with sparking plugs on Mark IV 'Osprey' machines at Lee-on-the-Solent. | 21th Jan 1936 | Box 58 \ 2 Scan282 | |
| Sparking plug trouble on an 'Osprey' aircraft, leading to engine cutting out. | 23th Jan 1936 | Box 58 \ 2 Scan283 | |
| Different spark plug types and performance issues from various locations. | 23th Jan 1936 | Box 58 \ 2 Scan284 | |
| Trouble with sparking plugs on Merlin engines due to leaded fuel and proposing a solution. | 27th Jan 1936 | Box 58 \ 2 Scan285 | |
| Requesting test results for B.G. Plugs, initially tested due to interest from the Dutch Government. | 1st Feb 1936 | Box 58 \ 2 Scan286 | |
| Testing B.G. plugs on a Kestrel engine, suggesting a full throttle test before a final report. | 3rd Feb 1936 | Box 58 \ 2 Scan287 | |
| Increased complaints of sparking plug trouble on Bentley cars compared to other models. | 6th Feb 1936 | Box 58 \ 2 Scan288 | |
| Sparking plug issues and misfiring in Bentley Engines related to deposits left by different types of fuel. | 5th Feb 1936 | Box 58 \ 2 Scan289 | |
| Pre-ignition and mica insulation flaking issues with Bentley sparking plugs. | 10th Feb 1936 | Box 58 \ 2 Scan290 | |
| Letter from AIRCO LIMITED regarding a Radio Screening Harness for engine testing. | 17th Feb 1936 | Box 58 \ 2 Scan291 | |
| Request to return Merlin E.5 type-test sparking plugs to Lodge and K.L.G. for inspection. | 18th Feb 1936 | Box 58 \ 2 Scan292 | |
| Letter from Imperial Airways regarding the performance of K.L.G. Wizard Sparking Plugs. | 22th Feb 1936 | Box 58 \ 2 Scan293 | |
| Letter from Chief Engineer H.L. Hall to a Mr. West, proposing a lunch meeting to discuss ignition troubles in modern high-duty engines. | 24th Feb 1936 | Box 58 \ 2 Scan294 | |
| Letter to Imperial Airways regarding a 'Wizard' plug sample and a proposed meeting. | 24th Feb 1936 | Box 58 \ 2 Scan295 | |
| The difficulties of using bottom-seated sparking plugs on Merlin engines and a proposed solution. | 24th Feb 1936 | Box 58 \ 2 Scan296 | |
| Copy of a letter from the Royal Air Force regarding the service life and maintenance of K.L.G. V7/3B sparking plugs in an Osprey aircraft's Kestrel V engine. | 24th Feb 1936 | Box 58 \ 2 Scan297 | |
| Incorrect spares and tools, specifically the spark plug gap gauge and tappet adjustment tool, for the 4 1/4 Litre Bentley. | 25th Feb 1936 | Box 58 \ 2 Scan298 | |
| The unsuitability of the existing sparking plug gap setting gauge on the 4 1/4 litre Bentley. | 27th Feb 1936 | Box 58 \ 2 Scan299 | |
| Letter to Airco Ltd. regarding test results for B.G. Sparking Plugs, noting a 'Pin holed' insulation fault. | 27th Feb 1936 | Box 58 \ 2 Scan300 | |
| Requesting a Yale lock for a sparking plug cupboard due to ongoing pilfering. | 27th Feb 1936 | Box 58 \ 2 Scan301 | |
| Letter from AIRCO Limited regarding tests on B.G. Sparking Plugs and communication with their Paris Factory. | 28th Feb 1936 | Box 58 \ 2 Scan302 | |
| Letter from Ethyl Export Corporation regarding the testing of a type 300A-1 H-T sparking plug. | 2nd Mar 1936 | Box 58 \ 2 Scan303 | |
| Letter from G.M.S. Plugs concessionaires to Bentley Motors requesting feedback on spark plug tests. | 3rd Mar 1936 | Box 58 \ 2 Scan304 | |
| Letter to Messrs. Crerar, Morgan & Co. Ltd. regarding the unsuitability of their H.S. type sparking plugs for Bentley engines. | 4th Mar 1936 | Box 58 \ 2 Scan305 | |
| Letter from Crerar, Morgan & Co. Ltd. regarding the performance of their G.M.S. spark plugs with leaded fuel. | 5th Mar 1936 | Box 58 \ 2 Scan306 | |
| Customer complaint about faulty sparking plugs for chassis GLJ-35, which were replaced and sent for testing. | 5th Mar 1936 | Box 58 \ 2 Scan307 | |
| Response to a report on the condition of a 'Demon' K.4498 aircraft's Kestrel engine, discussing bracing wires and sparking plugs. | 13th Mar 1936 | Box 58 \ 2 Scan308 | |
| Sent to Hucknall with a blueprint detailing the dimensions for a plug to be fitted in the Merlin E engine. | 16th Mar 1936 | Box 58 \ 2 Scan309 | |
| Request for test results on B.G. plugs, advising caution in the response to prevent use for publicity. | 17th Mar 1936 | Box 58 \ 2 Scan310 | |
| Follow-up request for test results on B.G. plugs, cautioning against their use for publicity purposes. | 17th Mar 1936 | Box 58 \ 2 Scan311 | |
| Testing of B.G. sparking plugs for Kestrel engines. | 24th Mar 1936 | Box 58 \ 2 Scan312 | |
| Installation inspection of type R.868 Integral Screened Sparking Plugs on a Merlin-Horsley engine. | 24th Mar 1936 | Box 58 \ 2 Scan313 | |
| Investigation into the excessive use and expenditure of sparking plugs for aero engine test beds. | 27th Mar 1936 | Box 58 \ 2 Scan314 | |
| Letter from French spark plug manufacturer LA BOUGIE B. G. regarding test results and future collaboration. | 31th Mar 1936 | Box 58 \ 2 Scan315 | |
| Letter responding to a query about the status of sparkling plugs undergoing engine tests. | 2nd Apr 1936 | Box 58 \ 2 Scan316 | |
| The order of sparking plugs for a Kestrel XVI engine. | 2nd Apr 1936 | Box 58 \ 2 Scan317 | |
| Appropriate spark plugs for Kestrel XVI engines intended for Yugoslavia. | 8th Apr 1936 | Box 58 \ 2 Scan318 | |
| Letter from French spark plug manufacturer B.G. regarding plug tests and a presentation to the Dutch Government. | 10th Apr 1936 | Box 58 \ 2 Scan319 | |
| Requisition list for apparatus required for servicing sparking plugs at Hucknall. | 16th Apr 1936 | Box 58 \ 2 Scan320 | |
| Procedure for conducting sparking plug voltage tests on Merlin engines at high altitudes. | 23th Apr 1936 | Box 58 \ 2 Scan321 | |
| Concluding remarks on tests for magneto development for high altitudes on the Merlin engine. | 23th Apr 1936 | Box 58 \ 2 Scan322 | |
| Tests of various spark plugs for the 25/30 HP chassis. | 24th Apr 1936 | Box 58 \ 2 Scan323 | |
| Insulation trouble on Bentley K.L.G. 765A plugs, leading to a very short lifespan. | 24th Apr 1936 | Box 58 \ 2 Scan324 | |
| Notification about an R.A.E. report on tests of B.G. screened sparking plugs being available in the library for inspection. | 30th Apr 1936 | Box 58 \ 2 Scan325 | |
| Report from a tester at Hawker's, Brooklands regarding fitting issues with Lodge sparking plugs and K.L.G. screens. | 27th Apr 1936 | Box 58 \ 2 Scan326 | |
| Characteristics of 14mm aero sparking plugs, attaching relevant curves. | 4th May 1936 | Box 58 \ 2 Scan327 | |
| Graph showing the volt-gap characteristics of K.L.G. aero plugs at room temperature. | 30th Apr 1936 | Box 58 \ 2 Scan328 | |
| Graph showing the volt-gap characteristics of two different aero plugs at room temperature. | 30th Apr 1936 | Box 58 \ 2 Scan329 | |
| Clarifying a misunderstanding over the procedure for supplying replacement sparking plugs for a Fairey 'Battle' aircraft. | 4th May 1936 | Box 58 \ 2 Scan330 | |
| Internal order for various pieces of electrical equipment for spark plug servicing at Hucknall. | 7th May 1936 | Box 58 \ 2 Scan331 | |
| Letter to Messrs. La Bougie regarding the completion of 110 hours of running tests on B.G. plugs in a Kestrel engine. | 7th May 1936 | Box 58 \ 2 Scan332 | |
| Return of 24 B.G. sparking plugs to the makers in France after testing. | 7th May 1936 | Box 58 \ 2 Scan333 | |
| Advice note and inspection certificate for 48 Lodge sparking plugs. | 13th May 1936 | Box 58 \ 2 Scan334 | |
| The results of sparking plug voltage tests on a Merlin 'C'.15 engine. | 13th May 1936 | Box 58 \ 2 Scan335 | |
| Sparking plug voltage test results for a Merlin 'C'.15 engine at various altitudes. | 15th May 1936 | Box 58 \ 2 Scan336 | |
| Engine cutting out at full boost due to faulty K.L.G. spark plugs at Handley Page Ltd. | 15th May 1936 | Box 58 \ 2 Scan337 | |
| Translated letter from 'La Bougie' 'B.G.' of Paris, concerning the performance of their sparking plugs in a Kestrel engine. | 15th May 1936 | Box 58 \ 2 Scan338 | |
| Letter from French spark plug manufacturer LA BOUGIE B. G. concerning spark plug service life. | 15th May 1936 | Box 58 \ 2 Scan339 | |
| The incompatibility of Lodge A.5.B sparking plugs with K.L.G. screened caps and the solution. | 18th May 1936 | Box 58 \ 2 Scan340 | |
| Letter from Lodge Plugs Limited responding to a complaint about the fitment of K.L.G. screens on A5B plugs. | 19th May 1936 | Box 58 \ 2 Scan341 | |
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