| Description | Date | Identifier | |
| Speedometer drive particulars for the Phantom II and 20 HP models. | 28th Oct 1929 | Box 50 \ 4 Scan316 | |
| Letter discussing a slow speedometer and the potential impact of different tyre sizes. | 29th Oct 1929 | Box 50 \ 4 Scan317 | |
| Instruction to despatch one speedometer to Mr. Minchin of Messrs. Peto & Radford. | 30th Oct 1929 | Box 50 \ 4 Scan318 | |
| Letter to Mr. Minchin of Messrs. Feto & Radford regarding the testing and adjustment of an instrument's speed readings. | 30th Oct 1929 | Box 50 \ 4 Scan319 | |
| Page 2 of a letter to Mr. Minchin of Messrs. Peto & Radford regarding a discrepancy and loss of magnetism. | 30th Oct 1929 | Box 50 \ 4 Scan320 | |
| Requesting clarification on a speedometer discrepancy between its marking (700) and gearing (675). | 31th Oct 1929 | Box 50 \ 4 Scan321 | |
| The correct speedometer calibration for a 20 HP chassis owned by a Mr. Minchin. | 1st Nov 1929 | Box 50 \ 4 Scan322 | |
| Letter from Peto & Radford to E. Fowler Clark regarding a speedometer and plans to transfer it to a new car. | 1st Nov 1929 | Box 50 \ 4 Scan323 | |
| Letter discussing the correct calibration for a speedometer on a 20 HP chassis. | 4th Nov 1929 | Box 50 \ 4 Scan324 | |
| Letter to Mr. Minchin of Messrs. Peto & Radford regarding the transfer of an item to a new car. | 4th Nov 1929 | Box 50 \ 4 Scan325 | |
| Letter from Peto & Radford concerning a faulty speedometer that registers incorrectly and does not return to zero. | 4th Nov 1929 | Box 50 \ 4 Scan326 | |
| Requesting minimum road wheel revolutions per mile figures for S.S. and 20 HP chassis. | 5th Nov 1929 | Box 50 \ 4 Scan327 | |
| Letter to a customer regarding a speedometer that was damaged in transit and has since been repaired and tested. | 6th Nov 1929 | Box 50 \ 4 Scan328 | |
| Letter from an accumulator manufacturer confirming a returned speedometer is now all right. | 11th Nov 1929 | Box 50 \ 4 Scan329 | |
| Wheel revolutions per mile for various tyres on 20 HP and Phantom II models. | 2nd Nov 1929 | Box 50 \ 4 Scan330 | |
| Specification sheet detailing speedometer revolutions per mile for various models and axle configurations. | 12th Nov 1929 | Box 50 \ 4 Scan331 | |
| The testing of A.T. speedometers on a Phantom II chassis, including temperature-related performance. | 22th Nov 1929 | Box 50 \ 4 Scan332 | |
| Analysis of speed indication errors at different temperatures and for different tyres. | 22th Nov 1929 | Box 50 \ 4 Scan333 | |
| Test report for an A.T. speedometer, recording indicated speed and drive revolutions per mile at various temperatures. | 29th Nov 1929 | Box 50 \ 4 Scan334 | |
| Check of the revolutions per mile for a 20 HP A.T. Speedometer. | 29th Nov 1929 | Box 50 \ 4 Scan335 | |
| Test report on an A.T. speedometer for a 20 HP chassis, analyzing its accuracy and temperature-related errors. | 2nd Dec 1929 | Box 50 \ 4 Scan336 | |
| Speedometer settings for car 18-EX, including tyre specifications and calculations. | 5th Dec 1929 | Box 50 \ 4 Scan337 | |
| Opinions and specifications for A.T. speedometers on Phantom II and 20 HP chassis. | 12th Dec 1929 | Box 50 \ 4 Scan338 | |
| Analysis of factors causing instrument reading errors for speed and mileage, specifically related to tyre size and temperature. | 6th Dec 1929 | Box 50 \ 4 Scan339 | |
| Speedometer calibration for chassis 18-EX due to the use of smaller tyres. | 6th Dec 1929 | Box 50 \ 4 Scan340 | |
| Mr. Royce's requested design alteration for the Goshawk I and II dynamo and brush holders, including sketches. | 11th Aug 1940 | Box 50 \ 5 Scan001 | |
| Request to order dynamo brushes from two different suppliers for experiments with the Goshawk dynamo. | 25th Jan 1921 | Box 50 \ 5 Scan002 | |
| List of different types and quantities of dynamo brushes. | 25th Feb 1921 | Box 50 \ 5 Scan003 | |
| Prints for the Goshawk I & II starter motor and dynamo, concerning brush holders and adaptations. | 16th Mar 1921 | Box 50 \ 5 Scan004 | |
| Extract detailing Mr. Royce's specifications for Goshawk I dynamo brushes and carcase dimensions. | 1st Jun 1921 | Box 50 \ 5 Scan005 | |
| Specification and testing of Morganite and Le Carbone brushes for dynamos and motors. | 30th Aug 1921 | Box 50 \ 5 Scan006 | |
| Parts and manufacturing of a 'Goshawk II' Dynamo Commutator. | 8th Aug 1921 | Box 50 \ 5 Scan007 | |
| Sourcing different grades of brushes for the 'Goshawk II' dynamo and motor after a change in brush holder dimensions. | 31th Aug 1921 | Box 50 \ 5 Scan008 | |
| The design and ordering of commutator brushes for the 'Goshawk II' S.S. Motor and Dynamo. | 9th Sep 1921 | Box 50 \ 5 Scan009 | |
| Request to order dynamo brushes from the Morgan Crucible Co. and Le Carbone Co. for the Goshawk dynamo. | 10th Sep 1921 | Box 50 \ 5 Scan010 | |
| Recommending 'Le Carbone' brushes over those from 'Morgan Crucible' for dynamos and motors. | 24th Oct 1921 | Box 50 \ 5 Scan011 | |
| Requesting the order of superior Le Carbone brushes for the Goshawk dynamo, following a note from Mr. Royce. | 7th Oct 1921 | Box 50 \ 5 Scan012 | |
| Instruction to experimentally produce a commutator for a 'Goshawk' II dynamo, substituting Mica insulation for the previously used Bakelite. | 1st Oct 1921 | Box 50 \ 5 Scan013 | |
| C.A.V. dynamo and starter motor for the 'Goshawk II', with a specific recommendation for LeCarbone brushes. | 9th Nov 1921 | Box 50 \ 5 Scan014 | |
| Production delays of the starter motor and dynamo due to issues with the bakelite commutator. | 9th Nov 1921 | Box 50 \ 5 Scan015 | |
| Design improvements for the Goshawk 11 Dynamo Drive. | 16th Dec 1921 | Box 50 \ 5 Scan016 | |
| Instructions and parts list for the Commutator Section of the 'Goshawk' 11 R.R. Dynamo. | 2nd Feb 1922 | Box 50 \ 5 Scan017 | |
| Query to confirm if grade 'Z' Le Carbone brushes are identical to the recommended grade 'O' for the Goshawk dynamo. | 6th Feb 1922 | Box 50 \ 5 Scan018 | |
| Suggested points of improvement for the Goshawk Dynamo. | 6th Feb 1922 | Box 50 \ 5 Scan019 | |
| Test report on a dynamo, noting advisability of increased tension on brush springs. | 8th Feb 1922 | Box 50 \ 5 Scan020 | |
| Letter from supplier Le Carbone clarifying the grading system of supplied brushes. | 8th Feb 1922 | Box 50 \ 5 Scan021 | |
| Internal request to order Goshawk Dynamo Brushes from the Le Carbone Co. | 18th Feb 1922 | Box 50 \ 5 Scan022 | |
| The quality, supply, and ordering of dynamo brushes for the Goshawk. | 18th Feb 1922 | Box 50 \ 5 Scan023 | |
| Request to order Goshawk dynamo brushes from The Morgan Crucible Co. | 23th Feb 1922 | Box 50 \ 5 Scan024 | |
| Order confirmation for brushes for the 'Goshawk II' starter motor and dynamo. | 1st Aug 1922 | Box 50 \ 5 Scan025 | |
| Letter from The Morgan Crucible Company regarding the despatch of Morganite brushes for trial. | 29th Mar 1922 | Box 50 \ 5 Scan026 | |
| Advice note from The Morgan Crucible Company for copper morganite brushes sent for trial. | 28th Mar 1922 | Box 50 \ 5 Scan027 | |
| The trial of different grades of dynamo brushes for the Goshawk. | 30th Mar 1922 | Box 50 \ 5 Scan028 | |
| The receipt and distribution of dynamo brushes from the Le Carbone Co. | 20th Apr 1922 | Box 50 \ 5 Scan029 | |
| Dynamo failures, brush issues, and commutator problems on the Goshawk II engine. | 25th Apr 1922 | Box 50 \ 5 Scan030 | |
| Order for Goshawk dynamo brushes from the Le Carbone Company. | 25th Apr 1922 | Box 50 \ 5 Scan031 | |
| Investigation into a burst commutator on a Goshawk 11 dynamo, comparing original, modified, and American designs. | 27th Apr 1922 | Box 50 \ 5 Scan032 | |
| Material choices for commutator separators, objecting to bakelite and suggesting alternatives or improvements. | 28th Apr 1922 | Box 50 \ 5 Scan033 | |
| Instructions for an experimental moulded Bakelite Commutator with mica insulation for the Goshawk II dynamo. | 28th Apr 1922 | Box 50 \ 5 Scan034 | |
| The trial of Condensite material for Goshawk dynamo commutators following the failure of bakelite parts. | 29th Apr 1922 | Box 50 \ 5 Scan035 | |
| Extract discussing failures and proposed solutions for electrical components on the Goshawk II engine. | 4th May 1922 | Box 50 \ 5 Scan036 | |
| Complaint regarding faulty pigtail connections on Goshawk Dynamo Brushes from the Le Carbone Company. | 2nd May 1922 | Box 50 \ 5 Scan037 | |
| Letter from supplier Le Carbone regarding a complaint and the supply of sample brushes. | 5th May 1922 | Box 50 \ 5 Scan038 | |
| Test report on Morganite brushes used on a Goshawk dynamo. | 5th May 1922 | Box 50 \ 5 Scan039 | |
| Extract from a letter concerning dynamo failures on Goshawk engines, detailing issues with brushes and commutator. | 8th May 1922 | Box 50 \ 5 Scan040 | |
| Correspondence regarding the supply of 'Mouldensite' moulding material for Goshawk engine commutators. | 8th May 1922 | Box 50 \ 5 Scan041 | |
| Letter discussing the supply of 'Mouldensite Powder', arranging a technical expert's visit, and sending a catalogue. | 8th May 1922 | Box 50 \ 5 Scan042 | |
| Cover letter regarding moulded commutators for the 'Goshawk' engine, enclosing correspondence with the Mouldensite Co. | 10th May 1922 | Box 50 \ 5 Scan043 | |
| Letter to The Mouldensite Co. about the supply of moulded commutators. | 10th May 1922 | Box 50 \ 5 Scan044 | |
| Quality control issues with a delivery of Le Carbone brushes for the Goshawk Dynamo, including faulty pig-tails and fitting problems. | 1st May 1922 | Box 50 \ 5 Scan045 | |
| Comparison of Morganite and Le Carbone brushes, focusing on dimensions, insulation, and pigtail length. | 11th May 1922 | Box 50 \ 5 Scan046 | |
| Follow-up letter from The Morgan Crucible Company regarding the trial of CM5 brushes sent for lighting dynamos. | 11th May 1922 | Box 50 \ 5 Scan047 | |
| Letter to The Morgan Crucible Co. Ltd. explaining an inability to answer an enquiry about Morganite Brushes due to works closure. | 15th May 1922 | Box 50 \ 5 Scan048 | |
| Blueprint for a Commutator Brush (Control) with assembly instructions. | 3rd May 1922 | Box 50 \ 5 Scan049 | |
| The despatch of three Commutator pieces to Mr. Royce for examination. | 17th May 1922 | Box 50 \ 5 Scan050 | |
| Improved type of commutator for the Goshawk II dynamo. | 17th May 1922 | Box 50 \ 5 Scan051 | |
| Recurring failure of a Goshawk dynamo commutator and plans for testing a new design. | 17th May 1922 | Box 50 \ 5 Scan052 | |
| Describing an alternative construction method for the improved commutator of the Goshawk 11 Dynamo. | 18th May 1922 | Box 50 \ 5 Scan053 | |
| New and revised parts for the R.R. Dynamo, concerning bearing brackets, brush holders, and windings. | 23th May 1922 | Box 50 \ 5 Scan054 | |
| Request for the remains of a failed Goshawk II commutator to be sent for inspection. | 18th May 1922 | Box 50 \ 5 Scan055 | |
| Bursting of commutators on the Goshawk 11 dynamo and proposing material and design changes. | 19th May 1922 | Box 50 \ 5 Scan056 | |
| Follow-up letter discussing dynamo modifications and material issues, recommending a switch from bakelite to a micanite ring for the commutator. | 19th May 1922 | Box 50 \ 5 Scan057 | |
| The re-control of leads from the brush gear for the Goshawk II Dynamo. | 19th May 1922 | Box 50 \ 5 Scan058 | |
| Drawing LeC 1582 for the control brush spring on the Goshawk 11 dynamo. | 22th May 1922 | Box 50 \ 5 Scan059 | |
| The drawing for a Goshawk 11 commutator built with micanite insulation. | 22th May 1922 | Box 50 \ 5 Scan060 | |
| Requesting a design alteration for the Goshawk II electric starter motor commutator. | 23th May 1922 | Box 50 \ 5 Scan061 | |
| Overheating failure of Goshawk II commutators and the need to test new insulating materials. | 23th May 1922 | Box 50 \ 5 Scan062 | |
| Use of powdered mica as a filler for bakelite gum. | 23th May 1922 | Box 50 \ 5 Scan063 | |
| Letter from Le Carbone regarding the submission of two lots of sample brushes of different grades. | 23th May 1922 | Box 50 \ 5 Scan064 | |
| Letter from a supplier discussing issues with brushes, including loose connections and insulation materials. | 23th May 1922 | Box 50 \ 5 Scan065 | |
| Letter from Le Carbone regarding two insulation samples (glass bead and cotton sleeve) for order No. 9092. | 23th May 1922 | Box 50 \ 5 Scan066 | |
| Design drawing for a Goshawk I standard type commutator. | 21th May 1921 | Box 50 \ 5 Scan067 | |
| Solder melting on the dynamo commutator of a Lucas Generator fitted to early Goshawk cars. | 24th May 1922 | Box 50 \ 5 Scan068 | |
| Use of mica dust as a filling for Bakelite and its properties compared to shellac. | 25th May 1922 | Box 50 \ 5 Scan069 | |
| Design alteration for the Goshawk 11 dynamo's field connections and brush holder insulation. | 27th May 1922 | Box 50 \ 5 Scan070 | |
| Confirming the agreed width of the control brush for the Goshawk dynamo. | 1st May 1922 | Box 50 \ 5 Scan071 | |
| Samples of Le Carbone brushes for the Goshawk Dynamo, detailing preferences for connection types and insulation. | 31th May 1922 | Box 50 \ 5 Scan072 | |
| Issuing new details and a blueprint for a Dynamo Commutator, section 8090. | 2nd Jun 1922 | Box 50 \ 5 Scan073 | |
| Fortunate failure of an experimental Goshawk dynamo brush which prevented the use of an unsafe design. | 7th Jun 1922 | Box 50 \ 5 Scan074 | |
| Letter from supplier Le Carbone regarding a sample flexible with bead insulation for order No.9092. | 9th Jun 1922 | Box 50 \ 5 Scan075 | |
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