| Description | Date | Identifier | |
| Graph comparing power curves at 4,000' for a moderate supercharger engine using standard versus long duration camshafts. | 20th Dec 1928 | Box 43 \ 3 Scan225 | |
| Filing cover sheet with handwritten reference numbers and a date stamp. | 3rd Jan 1929 | Box 43 \ 3 Scan226 | |
| Fitting original long duration camshafts to 'F' Type Engine No. 113. | 14th Feb 1929 | Box 43 \ 3 Scan227 | |
| Tests conducted on nitro-alloy crankshafts and camshafts in a development engine. | 2nd Nov 1929 | Box 43 \ 3 Scan228 | |
| Extract regarding the magneto selection for the Falcon X engine, considering Thomson-Houston and Watford Co. options. | 21th Dec 1925 | Box 43 \ 4 Scan001 | |
| Update on the construction progress of the Watford 12-cylinder single spark magneto for aero engines. | 9th Jun 1926 | Box 43 \ 4 Scan002 | |
| Test report on two Watford type IS12 aero magnetos for a Falcon X experimental engine, detailing a failure and subsequent repair. | 23th Sep 1926 | Box 43 \ 4 Scan003 | |
| Instruction sheet detailing the results of high and low-speed magneto sparking tests. | 29th Aug 1920 | Box 43 \ 4 Scan004 | |
| Attached report on Watford Aero Magnetos Type IS.12 for the Falcon X engine. | 23th Sep 1926 | Box 43 \ 4 Scan005 | |
| Test report on two Watford Type IS.12 Aero Magnetos for a Falcon X experimental engine. | 23th Sep 1926 | Box 43 \ 4 Scan006 | |
| Failure of distributor mouldings and wiring issues on Watford magnetos. | 8th Nov 1926 | Box 43 \ 4 Scan007 | |
| Summary of the troubles experienced with Watford magnetos, covering wiring, distributors, and other failures. | 9th Nov 1926 | Box 43 \ 4 Scan008 | |
| Issues with magneto components, including incorrectly drilled holes and problems caused by rushed production. | 10th Nov 1926 | Box 43 \ 4 Scan009 | |
| Faulty contact breaker component from a Falcon X magneto, detailing issues with the points and mechanism. | 10th Nov 1926 | Box 43 \ 4 Scan010 | |
| List of ten points for possible improvement on the Watford Type IS Aero Magnetos. | 10th Nov 1926 | Box 43 \ 4 Scan011 | |
| Noted issues and suggestions following an examination of a Watford IS.12 magneto for the Falcon X engine. | 10th Nov 1926 | Box 43 \ 4 Scan012 | |
| The return of a repaired contact breaker from North & Sons Ltd. | 12th Nov 1926 | Box 43 \ 4 Scan013 | |
| The return and identified faults of Watford magnetos for a Falcon X engine. | 16th Nov 1926 | Box 43 \ 4 Scan014 | |
| Issues with Watford Magnetos for the Falcon X, detailing correspondence with the supplier North & Sons regarding missing and incorrect parts. | 25th Nov 1926 | Box 43 \ 4 Scan015 | |
| Oil fouling issues with Aero Type Watford IS.12 Magnetos. | 30th Nov 1926 | Box 43 \ 4 Scan016 | |
| Sparking faults and magnetic leakage in two magnetos returned to Messrs. Norths for investigation. | 30th Nov 1926 | Box 43 \ 4 Scan017 | |
| The testing and fault diagnosis of Watford Aero Magnetos type IS.12, numbers 83134/5. | 24th Nov 1926 | Box 43 \ 4 Scan018 | |
| Extract regarding the fitting of magnetos from either Thomson-Houston or Watford. | 6th Nov 1926 | Box 43 \ 4 Scan019 | |
| Reported trouble with Watford magnetos and the need to increase stock to twelve units. | 8th Nov 1926 | Box 43 \ 4 Scan020 | |
| Investigation into a failed Watford aero magneto from a Falcon X engine. | 17th Nov 1926 | Box 43 \ 4 Scan021 | |
| Instructions regarding an oil leak into a magneto causing bad contact, and the subsequent fix. | 29th Jun 1920 | Box 43 \ 4 Scan022 | |
| List of points for discussion with Messrs. North's regarding magneto and distributor issues. | 24th Nov 1926 | Box 43 \ 4 Scan023 | |
| Status and anticipated improvements for Watford Type IS.12 magnetos. | 3rd Dec 1926 | Box 43 \ 4 Scan024 | |
| Clarifying the ownership of several pairs of Watford Type IS.12 Aero Magnetos. | 7th Dec 1926 | Box 43 \ 4 Scan025 | |
| Instruction sheet detailing the measurement of the safety gap on a Watford aero magneto type IS12, which was found to be too small. | 9th Dec 1926 | Box 43 \ 4 Scan026 | |
| Instruction regarding the safety gap on the B.T.H SC12-7 magneto for Watford machines. | 29th Jun 1920 | Box 43 \ 4 Scan027 | |
| Safety gaps of Watford Aero Magnetos Type IS.12, noting they are too small and comparing them to B.T.H. magnetos. | 10th Dec 1926 | Box 43 \ 4 Scan028 | |
| Specification of inspection and test for a Watford type IS.12 aero magneto for the Falcon X engine. | 10th Dec 1926 | Box 43 \ 4 Scan029 | |
| Testing procedures for a magneto, detailing various RPM runs, force limits, and spark gap settings. | 13th Dec 1926 | Box 43 \ 4 Scan030 | |
| Comparison of B.T.H. and Watford magnetos for the Falcon X aero engine, discussing performance tests and oil-related faults. | 13th Dec 1926 | Box 43 \ 4 Scan031 | |
| Watford magneto issues, including oil leaks into the contact breaker and distributor failures. | 18th Dec 1926 | Box 43 \ 4 Scan032 | |
| Critique and suggested modifications for a Watford magneto type IS.12. | 13th Dec 1926 | Box 43 \ 4 Scan033 | |
| Comparative electrical performance tests of B.T.H. and Watford magnetos for the Falcon X aero engine. | 13th Dec 1926 | Box 43 \ 4 Scan034 | |
| General specification of performance for a 12-cylinder, four spark per revolution magneto for the Falcon X aero engine. | 13th Dec 1926 | Box 43 \ 4 Scan035 | |
| Page 2 of a magneto utility test procedure, detailing spark gap testing under various conditions. | 13th Dec 1926 | Box 43 \ 4 Scan036 | |
| Specifications for magneto timing, sparking speed, and contact breaker lever operation. | 14th Dec 1926 | Box 43 \ 4 Scan037 | |
| Broken Watford Aero Magneto distributor, an attached report, and a request for a replacement. | 14th Dec 1926 | Box 43 \ 4 Scan038 | |
| Magneto distributor failure due to a spark jumping to earth, with a recommendation to increase the distance to prevent tracking. | 13th Dec 1926 | Box 43 \ 4 Scan039 | |
| Correspondence regarding a replacement distributor block for a Watford Aero Magneto and plans for a new rubber-based design. | 22th Dec 1926 | Box 43 \ 4 Scan040 | |
| Confirmation from North & Sons Ltd. to increase the safety gap length in Watford Aero Magnetos Type I.S.12. | 29th Dec 1926 | Box 43 \ 4 Scan041 | |
| Request for a sectional blueprint of the Watford IS.12 aero magneto. | 29th Dec 1926 | Box 43 \ 4 Scan042 | |
| Watford IS.12 Aero Magnetos, attaching assistant's reports WB.122 and WB.124. | 7th Jan 1927 | Box 43 \ 4 Scan043 | |
| Investigation into the oiling procedures and effects on the Watford IS.12 magnetos. | 6th Jan 1927 | Box 43 \ 4 Scan044 | |
| The correct lubrication levels for magnetos to avoid affecting the platinum points. | 7th Jan 1927 | Box 43 \ 4 Scan045 | |
| Critique of the low tension earthing connection method on Watford IS.12 magnetos. | 7th Jan 1927 | Box 43 \ 4 Scan046 | |
| Following up on an outstanding request for blueprints of a Watford I.S.12 type Aero Magneto. | 10th Jan 1927 | Box 43 \ 4 Scan047 | |
| Letter regarding Watford I.S.12 type Aero Magnetos, attaching correspondence from North & Sons Ltd. | 13th Mar 1927 | Box 43 \ 4 Scan048 | |
| Letter from North & Sons Ltd. discussing reports on oiling and the preparation of low tension wire. | 12th Jan 1927 | Box 43 \ 4 Scan049 | |
| Instructions detailing modifications to Watford IS12 magnetos for the Falcon X engine. | 25th Jan 1927 | Box 43 \ 4 Scan050 | |
| Comparison of a distributor design against the B.T.H model, noting its superior features but questioning an addition. | 8th Dec 1924 | Box 43 \ 4 Scan051 | |
| Instructions regarding magnetos, covering ventilation windows, weight, distributor nuts, and safety gaps. | 8th Dec 1924 | Box 43 \ 4 Scan052 | |
| Test report on two production magnetos, detailing pass/fail results for low-speed sparking. | 8th Dec 1924 | Box 43 \ 4 Scan053 | |
| Return of obsolete distributors and screens for Watford IS.12 Aero Magnetos. | 26th Jan 1927 | Box 43 \ 4 Scan054 | |
| Alterations and performance issues with Watford IS.12 magnetos for the Falcon X engine. | 31th Jan 1927 | Box 43 \ 4 Scan055 | |
| Modified Watford IS.12 magnetos for the Falcon X engine. | 25th Jan 1927 | Box 43 \ 4 Scan056 | |
| The effect of increasing the primary gap on the high-speed performance of Watford and B.T.H. aero magnetos. | 27th Jan 1927 | Box 43 \ 4 Scan057 | |
| The Air Ministry's decision not to proceed with the modification of Watford magnetos. | 8th Feb 1927 | Box 43 \ 4 Scan058 | |
| Replacement magneto for Eagle XVI engines after one failed a two-hour test. | 8th Feb 1927 | Box 43 \ 4 Scan059 | |
| Distributor timing specifications for a Watford IS12 Magneto No. 83133. | 9th Feb 1927 | Box 43 \ 4 Scan060 | |
| Calculations for piston position and spark timing relative to a hand magneto. | 9th Feb 1927 | Box 43 \ 4 Scan061 | |
| Contact breaker timing data for a Watford IS.12 Magneto, No. 83133. | 9th Feb 1927 | Box 43 \ 4 Scan062 | |
| Instructions regarding production testing and sparking issues with Watford IS12 magnetos. | 12th Feb 1927 | Box 43 \ 4 Scan063 | |
| Instruction note regarding the poor performance of magnetos under certain engine conditions. | 8th Dec 1924 | Box 43 \ 4 Scan064 | |
| Reply from North & Sons Ltd. regarding feedback on Watford I.S.12 Magnetos for the Falcon X engine. | 14th Feb 1927 | Box 43 \ 4 Scan065 | |
| The unsatisfactory bench test performance of Watford IS.12 magnetos, highlighting issues with sparking and timing. | 21th Feb 1927 | Box 43 \ 4 Scan066 | |
| Modifications to Watford type IS.12 magnetos and seeking A.I.D. confirmation for upgrades. | 24th Feb 1927 | Box 43 \ 4 Scan067 | |
| The investigation and comparative testing of a faulty Watford Aero Magneto from a Falcon engine. | 25th Feb 1927 | Box 43 \ 4 Scan068 | |
| Technical report discussing the performance and testing of a magneto contact breaker. | 25th Feb 1927 | Box 43 \ 4 Scan069 | |
| Correspondence regarding the performance of two Watford IS.12 magnetos and a reply from supplier North & Sons. | 1st Mar 1927 | Box 43 \ 4 Scan070 | |
| Inability to return certain magnetos and the arrangement of a meeting to discuss their use on the Falcon X engine. | 1st Mar 1927 | Box 43 \ 4 Scan071 | |
| Dispute over which magneto to use for an F.10 engine test and arranging a conference to resolve the matter. | 3rd Mar 1927 | Box 43 \ 4 Scan072 | |
| Requesting the location and delivery of specific Watford IS.12 magnetos. | 22th May 1921 | Box 43 \ 4 Scan073 | |
| Status of several Watford Aero Magnetos and inquiring about their return for correction. | 29th Mar 1927 | Box 43 \ 4 Scan074 | |
| Status and authorization of work on Watford Aero Magnetos. | 30th Mar 1927 | Box 43 \ 4 Scan075 | |
| Letter to Messrs. North & Sons regarding the unsatisfactory situation with Watford Aero Magnetos type IS.12. | 1st Apr 1927 | Box 43 \ 4 Scan076 | |
| Letter from North & Sons, Ltd. concerning modifications to Watford Aero Magnetos. | 5th Apr 1927 | Box 43 \ 4 Scan077 | |
| Letter to North & Sons regarding photostat copies of Make-Ratio Speed Curves for Aero Magneto Contact breakers. | 7th May 1927 | Box 43 \ 4 Scan078 | |
| Letter to the Air Ministry requesting permission to return faulty Watford magnetos to the makers for modification. | 9th May 1927 | Box 43 \ 4 Scan079 | |
| Production inspection and test results for the Watford Type IS.12 Magneto. | 11th Feb 1927 | Box 43 \ 4 Scan080 | |
| Visit by Mr. North concerning issues and alternative suppliers for aero engine magnetos. | 19th Aug 1927 | Box 43 \ 4 Scan081 | |
| Letter to North & Sons regarding issues with Watford I.S.12 Aero Magnetos, including a note from Mr. Royce. | 22th Aug 1927 | Box 43 \ 4 Scan082 | |
| Letter to Messrs. North & Sons regarding the return of out-of-date magnetos and requirements for new ones. | 25th Aug 1927 | Box 43 \ 4 Scan083 | |
| Performance report on four Watford Aero Magnetos, type IS.12, detailing issues and run times. | 25th Aug 1927 | Box 43 \ 4 Scan084 | |
| Arrangements for the modification of Watford Magnetos Type I.S.12. | 29th Aug 1927 | Box 43 \ 4 Scan085 | |
| Letter from North & Sons Ltd regarding the use of their Watford Magnetos in the Schneider Trophy race. | 28th Sep 1927 | Box 43 \ 4 Scan086 | |
| Test results for Aero Magneto Rotor M.I., comparing Watford and B.T.H. components. | 30th Sep 1927 | Box 43 \ 4 Scan087 | |
| From EFC to Roy regarding the overdue return of Watford magnetos from Messrs. Norths. | 6th Oct 1927 | Box 43 \ 4 Scan088 | |
| Use of a Watford magneto drive over a solid drive, citing lower risk and successful use in Napier engines for the Schneider Trophy Race. | 1st Nov 1927 | Box 43 \ 4 Scan089 | |
| Letter to North & Sons Ltd. regarding an upcoming engine type test for 12-cylinder aero magnetos. | 4th Nov 1927 | Box 43 \ 4 Scan090 | |
| Letter from North & Sons Ltd regarding the completion timeline for 12 cylinder aero magnetos for an engine type test. | 10th Nov 1927 | Box 43 \ 4 Scan091 | |
| Letter to Messrs. North & Sons, Ltd. regarding the scheduling of a Type Test. | 12th Nov 1927 | Box 43 \ 4 Scan092 | |
| Letter from North & Sons, Ltd. regarding a delay in submitting approved magnetos for a Type Test. | 17th Nov 1927 | Box 43 \ 4 Scan093 | |
| Letter to Messrs. North & Sons Ltd. regarding a revised specification for a 12-cylinder aero magneto for the Falcon aero engine. | 22th Nov 1927 | Box 43 \ 4 Scan094 | |
| Letter to Messrs. North & Sons Ltd. regarding a revised specification for 12-cylinder magnetos for Falcon aero engines. | 26th Nov 1927 | Box 43 \ 4 Scan095 | |
| Letter from North & Sons, Ltd. discussing the specifications and potential modification of 12 cylinder magnetos. | 29th Nov 1927 | Box 43 \ 4 Scan096 | |
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