| Description | Date | Identifier | |
| Notes on the properties and manufacturing tolerances of Ferobestos L.A. material. | 7th May 1941 | Box 136 \ 2 scan0325 | |
| Correcting a report on gearbox failures, specifically regarding the failed components and part numbers. | 2nd May 1941 | Box 136 \ 2 scan0326 | |
| Secret report detailing gearbox failures on various chassis models. | 1st May 1941 | Box 136 \ 2 scan0327 | |
| Analysis of gearbox failures concerning 2nd speed dog teeth and a review of gear tooth correction and strength calculations. | 1st May 1941 | Box 136 \ 2 scan0328 | |
| Gearbox tooth action and corrections. | 1st May 1941 | Box 136 \ 2 scan0329 | |
| Incorrectly labelled photographs of gearbox failure components. | 3rd May 1941 | Box 136 \ 2 scan0330 | |
| Design queries for the Senior Range Gearbox, specifically the felt seal, eccentric pins, and damper pump. | 3rd May 1941 | Box 136 \ 2 scan0331 | |
| The testing of a second Morris gearbox and the examination of the original. | 28th May 1941 | Box 136 \ 2 scan0332 | |
| The replacements carried out on Gear Box No. B.3.B.P. for Chassis B.22.AW. | 9th Jun 1941 | Box 136 \ 2 scan0333 | |
| Comparative analysis of quiet 1st speed gears for Junior Gearboxes, focusing on the Morris 8, Austin 8 and early B.V. models. | 30th Jun 1941 | Box 136 \ 2 scan0334 | |
| Analysis and proposed tests regarding 1st speed gearbox noise, comparing Morris and Austin designs. | 30th Jun 1941 | Box 136 \ 2 scan0335 | |
| Experimental development of new Senior Range gearboxes and related personnel issues at the Clan factory. | 9th Jul 1941 | Box 136 \ 2 scan0336 | |
| Development of a three-speed gearbox for a 10 HP engine, likely for the 'Wisp' project. | 6th Jul 1941 | Box 136 \ 2 scan0337 | |
| Grinding stage of gears for the new Senior Range Gearbox and arrangements for production in Glasgow. | 11th Jul 1941 | Box 136 \ 2 scan0338 | |
| Fitting a Cotal gearbox to Wolseley cars, outlining the outstanding design work required. | 23th Aug 1941 | Box 136 \ 2 scan0339 | |
| Proposing to test a Cotal gearbox on a car named 'the Ripple' during wartime. | 21th Aug 1941 | Box 136 \ 2 scan0340 | |
| Requesting a report on the urgent modifications needed for six new type gearboxes to avoid transportation stoppage. | 5th Jan 1942 | Box 136 \ 2 scan0341 | |
| Investigation into cone drag and baulking issues for the 3rd, 4th, and 2nd speed senior gearbox. | 23th Jan 1942 | Box 136 \ 2 scan0342 | |
| Modifications to gearbox speed wheels to overcome cone drag and baulking. | 23th Jan 1942 | Box 136 \ 2 scan0343 | |
| Issues with experimental car gear-boxes and outlining proposed solutions. | 3rd Feb 1942 | Box 136 \ 2 scan0344 | |
| Letter from Turbo Transmitters requesting detailed drawings to design and fit a hydraulic transmitter to a Bentley. | 17th Feb 1942 | Box 136 \ 2 scan0345 | |
| Letter to Turbo Transmitters Ltd. regarding the fitting of a hydraulic transmitter to a Bentley car. | 23th Feb 1942 | Box 136 \ 2 scan0346 | |
| Letter from Turbo Transmitters concerning the fitting of a transmitter and epicyclic gear to a Bentley. | 1st Mar 1942 | Box 136 \ 2 scan0347 | |
| Requesting prints of various component drawings. | 9th Mar 1942 | Box 136 \ 2 scan0348 | |
| Decision to fit a turbo-transmitter to a Bentley and the information required to do so. | 9th Mar 1942 | Box 136 \ 2 scan0349 | |
| Letter from Leyland Motors offering to sell back a four-speed synchro-mesh gearbox for £50. | 13th Mar 1942 | Box 136 \ 2 scan0350 | |
| Letter to Trubo Transmitters Ltd. enclosing prints of parts for fitting a Turbo Transmitter to a Bentley car. | 16th Mar 1942 | Box 136 \ 2 scan0351 | |
| Letter from Turbo Transmitters Ltd. acknowledging receipt of Bentley drawings and discussing a scheme for fitting a transmitter. | 18th Mar 1942 | Box 136 \ 2 scan0352 | |
| Letter from Turbo Transmitters Ltd. requesting drawings for a proposed transmitter on a Bentley chassis. | 4th May 1942 | Box 136 \ 2 scan0353 | |
| Letter to Turbo Transmitters Ltd. acknowledging a request to fit a unit to a Bentley. | 11th May 1942 | Box 136 \ 2 scan0354 | |
| Noisy gearbox complaint, detailing damaged parts and repairs for chassis B. 22. AW. | 28th Dec 1942 | Box 136 \ 2 scan0355 | |
| Photograph showing a broken spring retaining ring from a ball race housing assembly. | 28th Dec 1942 | Box 136 \ 2 scan0356 | |
| Photograph showing damaged teeth on a worm wheel (servo). | 28th Dec 1942 | Box 136 \ 2 scan0357 | |
| Photograph of a damaged overdrive outer cone. | 28th Dec 1942 | Box 136 \ 2 scan0358 | |
| Photograph of an overdrive cone insert which has revolved in the outer cone, showing wear marks. | 28th Dec 1942 | Box 136 \ 2 scan0359 | |
| Damaged gearbox parts from chassis B.22.AW following a complaint of noise. | 28th Dec 1942 | Box 136 \ 2 scan0360 | |
| Documenting a gearbox replacement on a Bentley chassis. | 27th Feb 1943 | Box 136 \ 2 scan0361 | |
| Gearbox replacement on a Silver-Riplet Chassis. | 3rd Mar 1943 | Box 136 \ 2 scan0362 | |
| The replacement of a gearbox and other parts on a Silver Riplet Chassis. | 23th Mar 1943 | Box 136 \ 2 scan0363 | |
| Photograph showing a broken spring retaining ring and the ball race housing assembly it came from. | 23th Mar 1943 | Box 136 \ 2 scan0364 | |
| Photograph showing damaged teeth on a servo worm wheel. | 23th Mar 1943 | Box 136 \ 2 scan0365 | |
| Photograph showing a damaged overdrive outer cone with broken teeth. | 23th Mar 1943 | Box 136 \ 2 scan0366 | |
| Photograph showing an overdrive cone insert that has spun within the outer cone. | 22th Jul 1943 | Box 136 \ 2 scan0367 | |
| Oil leaks in the Senior Range revised gearbox and proposing a design solution. | 22th Jul 1943 | Box 136 \ 2 scan0368 | |
| Scheme for modifying adjusting pins on the Senior Range Gearbox to cure oil leaks. | 28th Jan 1944 | Box 136 \ 2 scan0369 | |
| Modifications to the adjusting pins for the Senior Range Gearbox. | 1st Feb 1944 | Box 136 \ 2 scan0370 | |
| Letter discussing the design and application of a torque converter for experimental cars with different engine sizes. | 3rd Jan 1944 | Box 136 \ 2 scan0371 | |
| Listing the status of prints for Senior Range Gearbox and Front Suspension parts and details. | 6th Jan 1944 | Box 136 \ 2 scan0372 | |
| Status report on the completeness of various numbered sections and their associated part/drawing numbers. | 6th Jan 1944 | Box 136 \ 2 scan0373 | |
| Status update on the completion of drawings for various sections, detailing exceptions and their intended use. | 6th Jan 1944 | Box 136 \ 2 scan0374 | |
| Letter from the Self-Changing Gear Company regarding the development of a torque converter and a 2-speed gear. | 3rd Feb 1944 | Box 136 \ 2 scan0375 | |
| Inquiry into the performance and failures of the Minx gearbox in a 14 HP Hillman chassis. | 7th Feb 1944 | Box 136 \ 2 scan0376 | |
| Letter from Turbo Transmitters Limited discussing transmitter suitability for Meteor and Bentley engines. | 7th Jan 1944 | Box 136 \ 2 scan0377 | |
| Letter discussing the weight and performance characteristics of a transmitter, comparing it to standard transmissions. | 8th Apr 1944 | Box 136 \ 2 scan0378 | |
| Results of a Salerni turbo transmitter test and plans to fit one to a Bentley. | 10th Jan 1944 | Box 136 \ 2 scan0379 | |
| Letter discussing suggestions and testing procedures for a Turbo Transmitter. | 11th Jan 1944 | Box 136 \ 2 scan0380 | |
| Details and testing of a Salerni Turbo Transmitter. | 11th Jan 1944 | Box 136 \ 2 scan0381 | |
| Letter requesting a copy of previous correspondence dated 4th May 1942 from Captain Moore. | 12th Jan 1944 | Box 136 \ 2 scan0382 | |
| Letter from Turbo Transmitters Ltd to 'Roy' regarding a Bentley proposition and fitting a transmitter to a Carrier vehicle. | 17th Jan 1944 | Box 136 \ 2 scan0383 | |
| Listing technical prints and information provided in response to a request regarding a Turbo Transmitter. | 17th Jan 1944 | Box 136 \ 2 scan0384 | |
| Confidential letter discussing Drawing No. 41/GA, transmission for a car, and installing a transmitter in a Carrier. | 18th Jan 1944 | Box 136 \ 2 scan0385 | |
| Letter from Turbo Transmitters Limited to W. A. Robotham regarding work on a car and another job. | 20th Jan 1944 | Box 136 \ 2 scan0386 | |
| Failures and modifications of the Minx Gear Box in the 14 HP Hillman chassis. | 22th Feb 1944 | Box 136 \ 2 scan0387 | |
| Examining a Minx gearbox from a 14 HP Hillman chassis for potential use in the Silver Ripple. | 25th Feb 1944 | Box 136 \ 2 scan0388 | |
| Scheme for modifying adjusting pins on a Senior Range Gearbox to prevent oil leaks. | 28th Jan 1944 | Box 136 \ 2 scan0389 | |
| Letter arranging a meeting to discuss a transmitter, its chassis installation, and a reverse gear drawing. | 1st Feb 1944 | Box 136 \ 2 scan0390 | |
| Modification to the adjusting pins for the Senior Range Gearbox. | 1st Feb 1944 | Box 136 \ 2 scan0391 | |
| Letter from Turbo Transmitters Limited arranging a meeting to demonstrate a transmitter and reverse gear. | 2nd Feb 1944 | Box 136 \ 2 scan0392 | |
| Letter from W.A. Robotham's secretary arranging a meeting with Captain Moore of Turbo Transmitters Ltd. | 4th Feb 1944 | Box 136 \ 2 scan0393 | |
| Production and sub-letting of die-cast torque converters for land vehicles and post-war projects. | 28th Feb 1944 | Box 136 \ 2 scan0394 | |
| Letter from Clan Foundry requesting detail drawings and load calculations for a Bentley converter, with the aim of producing it from light alloy die castings. | 28th Feb 1944 | Box 136 \ 2 scan0395 | |
| Request for drawings and load calculations for a Bentley converter to explore making it from light alloy die castings. | 28th Feb 1944 | Box 136 \ 2 scan0396 | |
| Letter from a supplier discussing specifications and load figures for a 12 1/2 inch transmitter for a Bentley. | 2nd Mar 1944 | Box 136 \ 2 scan0397 | |
| Letter discussing the engineering challenges of a new transmitter, comparing steel versus aluminium construction, and its potential for the export trade. | 2nd Mar 1944 | Box 136 \ 2 scan0398 | |
| Letter to Turbo Transmitters Ltd. regarding technical information for two models of turbo transmitters for Bentley cars. | 2nd Mar 1944 | Box 136 \ 2 scan0399 | |
| Request for revised performance graphs to compare a car's transmission with its current gearbox. | 2nd Mar 1944 | Box 136 \ 2 scan0400 | |
| Letter to Turbo Transmitters, Ltd. addressing design queries and enclosing details for a Bentley project. | 3rd Mar 1944 | Box 136 \ 2 scan0401 | |
| List of enclosures detailing components including a crankshaft bolt, bearing housing, and flywheel arrangement. | 3rd Mar 1944 | Box 136 \ 2 scan0402 | |
| Letter to Turbo Transmitters Ltd. regarding design queries for a Bentley turbo transmitter. | 3rd Mar 1944 | Box 136 \ 2 scan0403 | |
| List of enclosures relating to engine, clutch, and chassis components. | 6th Mar 1944 | Box 136 \ 2 scan0404 | |
| From 'Rm' to 'Ev' about considering the manufacture of a torque converter from light alloy die castings. | 6th Mar 1944 | Box 136 \ 2 scan0405 | |
| Letter from Turbo Transmitters Limited discussing the supply and technical specifications of a transmitter for a Bentley. | 2nd Mar 1944 | Box 136 \ 2 scan0406 | |
| Letter discussing material choices for a transmitter, focusing on the challenges of using steel versus aluminium alloys. | 13th Mar 1944 | Box 136 \ 2 scan0407 | |
| The photographing and weighing of a disassembled 14 HP Hillman Gearbox. | 13th Mar 1944 | Box 136 \ 2 scan0408 | |
| Weight analysis of a Hillman 14 HP gearbox and its components. | 13th Mar 1944 | Box 136 \ 2 scan0409 | |
| Parts list with weights for gearbox, clutch, and associated mechanisms. | 13th Mar 1944 | Box 136 \ 2 scan0410 | |
| Exploded view photograph of a mechanical assembly, with components individually numbered. | 13th Mar 1944 | Box 136 \ 2 scan0411 | |
| Photo weight analysis of a Hillman 14 HP gearbox, focusing on gears and shafts. | 13th Mar 1944 | Box 136 \ 2 scan0412 | |
| Parts list detailing components, quantities, materials, reference numbers, and weights for a gearbox assembly. | 13th Mar 1944 | Box 136 \ 2 scan0413 | |
| Exploded view of gearbox components with numbered parts. | 27th Mar 1944 | Box 136 \ 2 scan0414 | |
| Apologising for overlooking a note on torque converters and discussing potential development. | 27th Mar 1944 | Box 136 \ 2 scan0415 | |
| Manufacture of Turbo Transmitters and the potential of making torque converters in-house versus using an alternative supplier. | 28th Mar 1944 | Box 136 \ 2 scan0416 | |
| Letter returning a 'Luber finer' filter, explaining its unsuitability for cars due to weight, dimensions, and cost. | 4th Oct 1938 | Box 136 \ 3 scan0001 | |
| Requesting the return of a filter after deciding not to proceed with a trial. | 5th Oct 1938 | Box 136 \ 3 scan0002 | |
| Letter from Luber-Finer (England) Ltd. regarding the return of a Luber-finer unit due to its unsuitable size and weight. | 8th Oct 1938 | Box 136 \ 3 scan0003 | |
| Letter from British Filters Ltd. regarding the performance of recently supplied filters and future opportunities. | 24th Oct 1938 | Box 136 \ 3 scan0004 | |
| Letter to British Filters Ltd. confirming satisfactory filter test results, requesting production pricing, and suggesting a new sales lead. | 25th Oct 1938 | Box 136 \ 3 scan0005 | |
| Letter from Simmonds Aerocessories Ltd. following up on a meeting and discussing Fram Cleaners. | 25th Oct 1938 | Box 136 \ 3 scan0006 | |
| Letter from British Filters Ltd. regarding satisfactory test results on General Filters and future pricing. | 26th Oct 1938 | Box 136 \ 3 scan0007 | |
| Test report comparing the performance of 'General' and 'Fram' oil reconditioner filters. | 1st Nov 1938 | Box 136 \ 3 scan0008 | |
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