| Description | Date | Identifier | |
| Complaint and investigation into faulty Goshawk 11 ignition coils. | 20th Aug 1923 | Box 49 \ 5 Scan026 | |
| Confirming the use of paper insulation and no varnish for the primary winding on 40/50 Stabalite coils for Goshawk. | 21th Aug 1923 | Box 49 \ 5 Scan027 | |
| Failures and testing procedures for the 40/50 Stabalite ignition coil for the Goshawk. | 21th Aug 1923 | Box 49 \ 5 Scan028 | |
| Failure analysis of four returned ignition coils. | 21th Aug 1923 | Box 49 \ 5 Scan029 | |
| Failures of the Standard 40/50 Stabalite Coil for Goshawk due to primary insulation. | 21th Aug 1923 | Box 49 \ 5 Scan030 | |
| Production testing protocol for ignition coils. | 12th Sep 1923 | Box 49 \ 5 Scan031 | |
| Continued testing of ignition coil primaries. | 17th Sep 1923 | Box 49 \ 5 Scan032 | |
| List detailing the status and type of coils on various chassis. | 19th Sep 1923 | Box 49 \ 5 Scan033 | |
| Specification for inspection and testing of the latest type 40/50 coil for the Goshawk engine ignition. | 22th Sep 1923 | Box 49 \ 5 Scan034 | |
| Production test procedure for a Goshawk 40/50 type ignition coil, without the use of a jig. | 22th Sep 1923 | Box 49 \ 5 Scan035 | |
| Testing procedure for a distributor and contact breaker assembly, page 2. | 22th Sep 1923 | Box 49 \ 5 Scan036 | |
| Specification for electrical testing, detailing voltage and current limits for a primary coil and a consecutive spark test. | 21th Sep 1923 | Box 49 \ 5 Scan037 | |
| Test results and specifications for Goshawk ignition coils. | 21th Sep 1923 | Box 49 \ 5 Scan038 | |
| The issues with using synthetic resin for 20 HP & 40/50 coil cases and the decision-making process for their design. | 14th Nov 1923 | Box 49 \ 5 Scan039 | |
| New coil design, its use in replacement work, and manufacturing observations. | 14th Nov 1923 | Box 49 \ 5 Scan040 | |
| List of coils for various chassis, detailing their type, material, and number of turns. | 3rd Dec 1923 | Box 49 \ 5 Scan041 | |
| List correlating Chassis numbers with corresponding Coil types and specifications. | 3rd Dec 1923 | Box 49 \ 5 Scan042 | |
| List of coils for various chassis, detailing their material, location, and turn count. | 23th Jan 1924 | Box 49 \ 5 Scan043 | |
| List of chassis numbers and codes cross-referenced with corresponding coil types. | 23th Jan 1924 | Box 49 \ 5 Scan044 | |
| Performance and mileage record for coil type PP No. 1. | 27th Mar 1927 | Box 49 \ 5 Scan045 | |
| Test and service log for coil type PP, number 2. | 27th Mar 1923 | Box 49 \ 5 Scan046 | |
| Service and performance log for a specific coil. | 27th Mar 1923 | Box 49 \ 5 Scan047 | |
| Summary list of coils used on various chassis, detailing materials and test information. | 19th Jun 1924 | Box 49 \ 5 Scan048 | |
| List of chassis models and their corresponding ignition coil types. | 19th Jun 1924 | Box 49 \ 5 Scan049 | |
| Instruction sheet detailing the results of production tests on two tall coils, TN1 and TN2, in 'Nestolite' cases. | 15th Sep 1924 | Box 49 \ 5 Scan050 | |
| Observations on the intermittent performance of a coil. | 29th Jun 1920 | Box 49 \ 5 Scan051 | |
| Use of different insulating materials for coil cases, comparing the unreliable Nestolite with a new 'Red Compound Dough'. | 17th Sep 1924 | Box 49 \ 5 Scan052 | |
| Requesting the fitting of a new 'Standard Tall Coil in Nestolite Case' to vehicle 49-GB. | 22th Sep 1924 | Box 49 \ 5 Scan053 | |
| The test results for two tall coils in Nestolite cases, with one being returned for improvement. | 22th Sep 1924 | Box 49 \ 5 Scan054 | |
| Table of specifications for coil primary windings. | 25th Sep 1929 | Box 49 \ 5 Scan055 | |
| Cover memo for a report prepared by Mr. Olley on parts for the American chassis. | 29th Jul 1920 | Box 49 \ 5 Scan056 | |
| Cover letter from Rolls-Royce of America listing six enclosed reports on various automotive components and tests. | 15th Jul 1920 | Box 49 \ 5 Scan057 | |
| Letter to Claude Johnson regarding issues with electrical apparatus on postwar chassis and the resulting service expenses. | 9th Dec 1920 | Box 49 \ 5 Scan058 | |
| Chasing the Derby factory for more complete replies on luggage carriers, spark plugs, and magnetos. | 8th Dec 1920 | Box 49 \ 5 Scan059 | |
| Comparison of serviceability between Watford and American magnetos, highlighting issues and resource drains. | 1st Dec 1920 | Box 49 \ 5 Scan060 | |
| Revised opinion on the quality of American electrical units following a visit to the U.S.A. | 8th Feb 1921 | Box 49 \ 5 Scan061 | |
| Comparison of the quality and cost of American and English electrical components and spares. | 1st Feb 1921 | Box 49 \ 5 Scan062 | |
| Cost comparison table for a Watford Magneto, detailing the cost at Springfield versus the U.S.A. equivalent. | 1st Feb 1921 | Box 49 \ 5 Scan063 | |
| Visit to U.S. electrical component factories to assess Bosch and Westinghouse starter motors, generators, and magnetos. | 2nd Feb 1921 | Box 49 \ 5 Scan064 | |
| Offer from the Bosch Company for magnetos, starter motors, generators, and battery ignition sets. | 1st Feb 1921 | Box 49 \ 5 Scan065 | |
| Visits to Bosch and Westinghouse factories regarding automotive electrical components. | 1st Feb 1921 | Box 49 \ 5 Scan066 | |
| Equipment guarantee terms, comparing a standard 90-day/3,000-mile guarantee with a potential one-year guarantee. | 1st Feb 1921 | Box 49 \ 5 Scan067 | |
| Letter from American Bosch Magneto Company regarding the sale price and performance tests of their magnetos in comparison to German Bosch and Watford magnetos. | 5th Jan 1921 | Box 49 \ 5 Scan068 | |
| Letter detailing proposals for supplying ignition and lighting systems, including service arrangements and testing protocols. | 10th Dec 1920 | Box 49 \ 5 Scan069 | |
| Letter page discussing the price and superiority of American Bosch magnetos and proposing to supply battery sets. | 10th Dec 1920 | Box 49 \ 5 Scan070 | |
| Cost differences between English and American electrical units for the 40/50 HP U.S.A. Chassis. | 15th Feb 1921 | Box 49 \ 5 Scan071 | |
| Differences between U.S.A. and European chassis and the process for approving new units. | 15th Feb 1921 | Box 49 \ 5 Scan072 | |
| Magneto performance, spark gaps, and a comparison of dynamo systems. | 19th May 1921 | Box 49 \ 5 Scan073 | |
| Comparing Delco and Bijur electrical systems and discussing tests on induction pipes. | 19th May 1921 | Box 49 \ 5 Scan074 | |
| Tests concerning the mechanical distribution of liquid petrol to engine cylinders. | 19th May 1921 | Box 49 \ 5 Scan075 | |
| Copy of a telegram from Mr. Royce to Springfield regarding electrical equipment and parts production. | 18th Jun 1921 | Box 49 \ 5 Scan076 | |
| Modification to the 40/50 HP starter motors by using coarser field copper for increased engine speed. | 12th Jul 1921 | Box 49 \ 5 Scan077 | |
| Extract concerning permission for U.S.A. to adopt Bosch and Bijur electrical components. | 22th Jul 1921 | Box 49 \ 5 Scan078 | |
| Examination of various U.S.A. switch boxes with a recommendation for the Delco from the Marmon car. | 22th Jul 1921 | Box 49 \ 5 Scan079 | |
| Report discussing the placement and selection of dashboard electrical components like switches, buzzers, and fuses. | 22th Jul 1921 | Box 49 \ 5 Scan080 | |
| Continued note on the placement of a buzzer versus fuses in a circuit. | 22th Jul 1921 | Box 49 \ 5 Scan081 | |
| Expressing dissatisfaction with the electrical equipment for the U.S.A. Springfield chassis and considering alternatives. | 20th Sep 1923 | Box 49 \ 5 Scan082 | |
| Reliability of Springfield electrical equipment, including Westinghouse dynamos and American Bosch ignition systems. | 18th Oct 1923 | Box 49 \ 5 Scan083 | |
| Silvex spark plugs, comparing them to A.C., Champion, and German Bosch types. | 8th Oct 1920 | Box 49 \ 5 Scan084 | |
| Spark plugs, requesting a report based on an attached letter from America. | 29th Oct 1920 | Box 49 \ 5 Scan085 | |
| Test procedures for various makes of sparking plugs. | 9th Feb 1921 | Box 49 \ 5 Scan086 | |
| Test report comparing the performance of various types of spark plugs. | 9th Feb 1921 | Box 49 \ 5 Scan087 | |
| Report evaluating and ranking Mercury, Champion U.S.A., and Bethlehem U.S.A. spark plugs, recommending an initial order of Mercury plugs. | 9th Feb 1921 | Box 49 \ 5 Scan088 | |
| Technical memorandum comparing various brands and designs of sparking plugs. | 16th Feb 1921 | Box 49 \ 5 Scan089 | |
| Conclusion of tests recommending the standardization of Champion and Mercury spark plugs for U.S.A. and English made cars respectively. | 16th Feb 1921 | Box 49 \ 5 Scan090 | |
| Forwarding a copy of a letter from America concerning Spark Plugs. | 24th Mar 1921 | Box 49 \ 5 Scan091 | |
| Letter regarding the abandonment of Bethlehem spark plugs in favour of the new Champion A-63 plugs. | 7th Mar 1921 | Box 49 \ 5 Scan092 | |
| Sales letter from Alfred Graham & Company regarding their electrical autohorn. | 18th Feb 1921 | Box 49 \ 5 Scan093 | |
| Second page of a letter with a postscript offering to design a special model to suit particular requirements. | 10th Dec 1920 | Box 49 \ 5 Scan094 | |
| Forwarding a letter and leaflets from Alfred Graham & Co. for perusal. | 21th Feb 1921 | Box 49 \ 5 Scan095 | |
| Information on the sound travel distance of an Alfred Graham & Co. Electrical Autohorn. | 23th Feb 1921 | Box 49 \ 5 Scan096 | |
| Internal correspondence regarding the Alfred Graham & Co. Electrical Autohorn and a special polished aluminium model. | 28th Feb 1921 | Box 49 \ 5 Scan097 | |
| Correspondence regarding an Electrical Autohorn from Alfred Graham & Co. | 3rd Mar 1921 | Box 49 \ 5 Scan098 | |
| Letter from Alfred Graham & Co. regarding the audibility of their 'Graham' Electrical Autohorn and arranging a visit. | 2nd Mar 1921 | Box 49 \ 5 Scan099 | |
| Correspondence with Alfred Graham & Co. regarding the supply and testing of Electrical Autohorns. | 10th Mar 1921 | Box 49 \ 5 Scan100 | |
| New all-aluminium electrical autohorn from supplier Alfred Graham & Co. | 14th Mar 1921 | Box 49 \ 5 Scan101 | |
| Advertising brochure for the Graham Electrical Autohorn. | 14th Mar 1921 | Box 49 \ 5 Scan102 | |
| Price list and particulars for various types of car horns and fittings. | 14th Mar 1921 | Box 49 \ 5 Scan103 | |
| Advertisement for the 'Graham' Electrical Autohorn, a special model for motor car manufacturers. | 14th Mar 1921 | Box 49 \ 5 Scan104 | |
| Leaflet detailing the features and manufacturers of the 'Graham' Autohorn. | 23th Mar 1921 | Box 49 \ 5 Scan105 | |
| Long Aluminium Trumpet received from Alfred Graham & Co Ltd. for test purposes. | 23th Mar 1921 | Box 49 \ 5 Scan106 | |
| The failure of an Appollo horn on an experimental car and its replacement. | 6th Apr 1921 | Box 49 \ 5 Scan107 | |
| Letter from Alfred Graham & Company regarding a delay in sending a Motor Driven Horn sample for testing. | 26th Jul 1922 | Box 49 \ 5 Scan108 | |
| Testing and reporting on 'Graham' Electrical Autohorns from Alfred Graham & Co. | 30th Sep 1921 | Box 49 \ 5 Scan109 | |
| Letter from Alfred Graham & Company following up on the testing of their 'Graham' Electrical Autohorns and suggesting an alternative model. | 29th Sep 1921 | Box 49 \ 5 Scan110 | |
| Price list for 'Graham' electrical autohorns, special models in polished aluminium. | 30th Sep 1926 | Box 49 \ 5 Scan111 | |
| Advertisement leaflet for the 'Graham' Electrical Autohorn. | 30th Sep 1926 | Box 49 \ 5 Scan112 | |
| Receipt notification slip from 'ROY'. | 19th Dec 1922 | Box 49 \ 5 Scan113 | |
| Letter from Alfred Graham & Company regarding their new ability to supply the 'Graham-Sparton' electric horn. | 18th Dec 1922 | Box 49 \ 5 Scan114 | |
| Letter from Alfred Graham & Co. proposing a superior motor-driven warning horn for consideration, detailing its US production and sample delivery. | 30th Dec 1922 | Box 49 \ 5 Scan115 | |
| American-made Sparton Horn and its proposed manufacture in the UK with English styling. | 30th Dec 1922 | Box 49 \ 5 Scan116 | |
| Requesting comments on a Sparton Horn sample submitted by the Graham Company. | 23th Feb 1923 | Box 49 \ 5 Scan117 | |
| Letter from Alfred Graham & Company regarding a Sparton Motor Driven Horn and a proposal to submit a 12-volt Model AUM. | 14th Mar 1923 | Box 49 \ 5 Scan118 | |
| Letter from Alfred Graham & Company confirming an interview for Wednesday, June 6th. | 2nd Jun 1923 | Box 49 \ 5 Scan119 | |
| Letter to Messrs. Alfred Graham & Co. acknowledging receipt of a horn for testing. | 8th Dec 1925 | Box 49 \ 5 Scan120 | |
| Letter from Alfred Graham & Company regarding a Sparton horn for test purposes. | 27th Nov 1925 | Box 49 \ 5 Scan121 | |
| Promotional document for the Sparton S.O.S. and S.O.S. Junior horns. | 27th Nov 1925 | Box 49 \ 5 Scan122 | |
| Advertisement for 'The New Sparton SOS' car horn. | 27th Nov 1925 | Box 49 \ 5 Scan123 | |
| Advertisement for the Sparton SOS motor horn, marketed as a Christmas gift. | 5th Mar 1929 | Box 49 \ 5 Scan124 | |
| Change from Klaxon rotary horns to buzzer-type horns, comparing Robert Bosch and Sparton models. | 5th Mar 1929 | Box 49 \ 5 Scan125 | |
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