| Description | Date | Identifier | |
| Confirming agreements and discussing faults regarding condensers for the 40/50 & 20 HP chassis. | 14th Jun 1923 | Box 34 \ 1 Scan327 | |
| Producing and examining condensers for the first 50 cars to check for faults. | 14th Jun 1923 | Box 34 \ 1 Scan328 | |
| Test report for a returned condenser, confirming it is functioning correctly. | 6th Jul 1923 | Box 34 \ 1 Scan329 | |
| Note directing to a file regarding the Phantom Condenser for further correspondence. | 6th Jul 1923 | Box 34 \ 1 Scan330 | |
| Water outlet connections with rubber joints for the Falcon and Eagle engines. | 28th Jun 1916 | Box 34 \ 2 Scan001 | |
| Proposal to simplify water connections on jackets by replacing screw unions with steel tubes and clips. | 4th Jul 1916 | Box 34 \ 2 Scan002 | |
| Modifications to water connection fittings on the 'Hawk' aero engine. | 5th Jul 1916 | Box 34 \ 2 Scan003 | |
| Technical memorandum discussing improvements and alternative designs for water pipe clips. | 17th Jul 1916 | Box 34 \ 2 Scan004 | |
| Recommendation to adopt plain water connections without unions as standard on the Falcon and Hawk Engines. | 27th Dec 1916 | Box 34 \ 2 Scan005 | |
| Requesting a blueprint for a standardized plain water connection part for the Eagle engine, which is being tested in aluminium. | 1st Jan 1917 | Box 34 \ 2 Scan006 | |
| Design flaw in a standardized aluminium plain water connection for an experimental engine. | 5th Jan 1917 | Box 34 \ 2 Scan007 | |
| Standardisation of spherical type unions and a fault found in smaller gunmetal sizes. | 25th Jun 1925 | Box 34 \ 2 Scan008 | |
| Redesign, material changes, and testing of spherical seated unions for standardization. | 19th Dec 1925 | Box 34 \ 2 Scan009 | |
| The decision to omit pegs for locking pipe unions in aluminium castings. | 1st Aug 1926 | Box 34 \ 2 Scan010 | |
| The principle of using a taper pin to locate a nipple for a union in an aluminium boss. | 25th Aug 1926 | Box 34 \ 2 Scan011 | |
| New design for Spherical Seated Unions, comparing dimensions and thread standards. | 5th Jan 1927 | Box 34 \ 2 Scan012 | |
| Design, material, and standardization of new pipe unions. | 9th Jan 1927 | Box 34 \ 2 Scan013 | |
| Design and approval by Mr. Royce of spherical seated unions with reduced dimensions. | 12th Jan 1927 | Box 34 \ 2 Scan014 | |
| Experiment to enlarge drain holes on a hand magneto casing, as per Mr. Royce's instructions. | 6th Jun 1916 | Box 34 \ 2 Scan015 | |
| Internal memorandum regarding an issue with a hand magneto filling with oil. | 30th May 1916 | Box 34 \ 2 Scan016 | |
| Enlargement of drain holes in the hand magneto casing. | 15th Jun 1916 | Box 34 \ 2 Scan017 | |
| Quoting Mr Royce on rectifying an issue with a hand-starting magneto filling with oil. | 31th Jul 1916 | Box 34 \ 2 Scan018 | |
| Cancelled modification note for an Eagle Engine's hand magneto concerning larger drain holes. | 15th Aug 1916 | Box 34 \ 2 Scan019 | |
| Extract detailing the strength testing procedure for hand magnetos and starting gear. | 30th May 1916 | Box 34 \ 2 Scan020 | |
| Experiment involving prematurely firing an engine while it is being slowly revolved. | 6th Jun 1916 | Box 34 \ 2 Scan021 | |
| Request for a hand starter for an experiment on the RE 250 HP engine. | 19th Jun 1916 | Box 34 \ 2 Scan022 | |
| Instruction sheet confirming a 250 HP hand starter experiment is complete and ready for testing. | 15th Aug 1919 | Box 34 \ 2 Scan023 | |
| Agreement to cancel an engine experiment concerning premature firing due to difficulty obtaining the necessary equipment. | 1st Jan 1917 | Box 34 \ 2 Scan024 | |
| Cause of hand starter gear breakages on 'Eagle' engines and proposals for strengthening the components. | 3rd Jun 1916 | Box 34 \ 2 Scan025 | |
| The necessity of hardening sun wheel teeth and requesting information on worm and shaft failures. | 3rd Jun 1916 | Box 34 \ 2 Scan026 | |
| Initiating an experiment regarding hand starter gear breakages on Eagle engines. | 6th Jun 1916 | Box 34 \ 2 Scan027 | |
| Issues with bending wormwheel shafts on hand starters and the plan to replace them with strengthened versions. | 6th Jun 1916 | Box 34 \ 2 Scan028 | |
| Failed worm wheel shaft, clarifying a description error, and detailing old and new part numbers. | 8th Jun 1916 | Box 34 \ 2 Scan029 | |
| Cancellation notice for a static torque test on a hand starter's larger wormwheel shaft. | 27th Feb 1917 | Box 34 \ 2 Scan030 | |
| Arrangement for making six sets of continuous current revolution indicators for the Admiralty. | 13th May 1916 | Box 34 \ 2 Scan031 | |
| Instruction request for the production of five sets of Magneto Speedometers for 250 HP engines. | 21th Aug 1916 | Box 34 \ 2 Scan032 | |
| Advising Mr. Clark of an experimental Electrical Speed Indicator fitted to a 250 HP Engine A 2. | 12th Dec 1916 | Box 34 \ 2 Scan033 | |
| Instruction sheet for fitting experimental parts to a 260HP Engine A2. | 12th Dec 1916 | Box 34 \ 2 Scan034 | |
| Test report cover page for C.M. & C.M.1 Morganite brushes on a speedometer. | 11th Jan 1917 | Box 34 \ 2 Scan035 | |
| Confirmation of experiments fitted to an A2 engine, including an electrical speedometer and a wheelcase with lock nuts. | 11th Jan 1917 | Box 34 \ 2 Scan036 | |
| Successful bench test of a magneto speedometer and drive, with a suggestion for further testing on an aeroplane. | 30th Mar 1917 | Box 34 \ 2 Scan037 | |
| Extract regarding fitting an electrical speed indicator and a consumption tank to a car for testing. | 4th Jun 1918 | Box 34 \ 2 Scan038 | |
| Experimental parts fitted to chassis 7 C.A. | 13th Jun 1917 | Box 34 \ 2 Scan039 | |
| Extract detailing parts fitted to Mr. Royce's car, covering rear springs, shock absorbers, and an electrical speed indicator. | 15th Jun 1917 | Box 34 \ 2 Scan040 | |
| End play of a Hoffmann ball bearing for a magneto speedometer. | 4th Jul 1917 | Box 34 \ 2 Scan041 | |
| Letter from the Department of Aircraft Production enclosing an R.A.E. report on a Magneto Speedometer. | 2nd Aug 1918 | Box 34 \ 2 Scan042 | |
| Letter from the Department of Aircraft Production regarding a test report on a Magneto Speedometer. | 2nd Aug 1918 | Box 34 \ 2 Scan043 | |
| Letter to a tester regarding engine testing, a new radiator, an electric counter, and propeller trials. | 15th Aug 1918 | Box 34 \ 2 Scan044 | |
| Continued letter inquiring about the standard Eagle engine and the D.H.10 aircraft fitted with a Liberty engine. | 15th Aug 1918 | Box 34 \ 2 Scan045 | |
| Letter regarding the return of a magneto speedometer after testing at R.A.E. | 26th Sep 1918 | Box 34 \ 2 Scan046 | |
| Order for German Silver Resistance Wire for a Magneto Speedometer. | 19th Mar 1919 | Box 34 \ 2 Scan047 | |
| Voltage output particulars of the magneto speedometer, also known as a revolution counter. | 16th Aug 1922 | Box 34 \ 2 Scan048 | |
| Instructions detailing two generators for a Magneto Speed Indicator and their specific resistance values. | 5th Oct 1922 | Box 34 \ 2 Scan049 | |
| Specifications for a machine with aluminium end-plates, detailing its components. | 6th Nov 1918 | Box 34 \ 2 Scan050 | |
| Instructions detailing the characteristics of a Weston instrument, including its scale, voltage, current, and resistance. | 6th Nov 1918 | Box 34 \ 2 Scan051 | |
| Test results for a resistance bobbin, including calculations for volts, amperes, and a table of machine speed versus scale readings. | 6th Nov 1918 | Box 34 \ 2 Scan052 | |
| Test report for a Magneto Speed Indicator, detailing resistance adjustments and reading corrections. | 12th Oct 1922 | Box 34 \ 2 Scan053 | |
| Detailed specification for a Magneto Speed Indicator and its D.C. generator component. | 17th Oct 1922 | Box 34 \ 2 Scan054 | |
| The resistance characteristics and calibration of a Weston instrument. | 17th Oct 1922 | Box 34 \ 2 Scan055 | |
| Report page discussing eddy currents in an armature core, with a diagram showing slot dimensions. | 17th Oct 1922 | Box 34 \ 2 Scan056 | |
| Letter from Hightensite Limited promoting their Ebonite and Hightensite goods and services. | 29th Aug 1919 | Box 34 \ 2 Scan057 | |
| Advertisement for Hightensite Ltd's ebonite separators for battery accumulators and other related parts. | 1st Aug 1919 | Box 34 \ 2 Scan058 | |
| Letter to The Hightensite Co., Ltd. requesting samples of various insulating materials. | 1st Sep 1919 | Box 34 \ 2 Scan059 | |
| Letter from Hightensite Limited regarding sending product samples and proposing to cover an ignition tube with Ebonite. | 5th Sep 1919 | Box 34 \ 2 Scan060 | |
| Letter from Hightensite Limited regarding the dispatch of samples and an offer for Ebonite covering for ignition tubes. | 24th Sep 1919 | Box 34 \ 2 Scan061 | |
| Inquiry for a sample of ebonite covering for ignition tubes. | 6th Sep 1919 | Box 34 \ 2 Scan062 | |
| Letter to Messrs. Hightensite Limited acknowledging receipt of mouldings and enquiring about the supply of sample Ebonite Mouldings. | 30th Sep 1919 | Box 34 \ 2 Scan063 | |
| Record of Hightensite and Ebonite moulding samples with inserts sent by post. | 8th Oct 1919 | Box 34 \ 2 Scan064 | |
| Letter from Hightensite Limited regarding samples of Ebonite and Hightensite mouldings with embedded metal. | 30th Sep 1919 | Box 34 \ 2 Scan065 | |
| Experimental ebonite-covered ignition tube supplied by Messrs. Hightensite Ltd. | 13th Nov 1919 | Box 34 \ 2 Scan066 | |
| Examination of an ignition tube ebonite cover supplied by Messrs Hightensite Ltd. | 15th Nov 1919 | Box 34 \ 2 Scan067 | |
| Feedback on an ebonite-covered ignition tube supplied by Messrs. Hightensite Ltd. | 18th Nov 1919 | Box 34 \ 2 Scan068 | |
| Quality of ebonite covered ignition tubes from The Hightensite Co. Ltd. | 27th Nov 1919 | Box 34 \ 2 Scan069 | |
| Assessing a sample tube and concluding it is as good as the current material being used. | 27th Nov 1919 | Box 34 \ 2 Scan070 | |
| Letter from Hightensite Limited following up on a quotation for a sample Ebonite-covered Ignition Tube. | 8th Nov 1919 | Box 34 \ 2 Scan071 | |
| Letter from Hightensite Limited regarding a quotation for covering Ignition Tubes with Ebonite. | 30th Oct 1919 | Box 34 \ 2 Scan072 | |
| Quotation from Hightensite Limited for covering steel ignition tubes with Ebonite. | 30th Oct 1919 | Box 34 \ 2 Scan073 | |
| Letter from Hightensite Limited regarding the machining, polishing, and delivery of tubes. | 24th Oct 1919 | Box 34 \ 2 Scan074 | |
| Letter forwarding a booklet from Hightensite Ltd. on improvements in insulating material. | 1st Jun 1921 | Box 34 \ 2 Scan075 | |
| Booklet from Hightensite Limited regarding improvements in insulating materials. | 15th Jun 1921 | Box 34 \ 2 Scan076 | |
| Sending samples of Hightensite sheet and tubing for testing. | 15th Jun 1921 | Box 34 \ 2 Scan077 | |
| Forwarding a letter and samples of a heat-resisting material from Hightensite Ltd. | 21th Jun 1921 | Box 34 \ 2 Scan078 | |
| Copy of a letter from Hightensite Limited regarding a heat-resisting material, with samples sent for testing. | 20th Jun 1921 | Box 34 \ 2 Scan079 | |
| Requesting a report on the testing of samples from Hightensite Ltd. | 11th Jul 1921 | Box 34 \ 2 Scan080 | |
| Instruction regarding the delayed testing of 'Hightensite' samples. | 12th Jul 1921 | Box 34 \ 2 Scan081 | |
| Extract discussing the positioning of bolt holes and accessibility of ignition plugs for the Eagle engine. | 30th Mar 1915 | Box 34 \ 2 Scan082 | |
| Extract regarding alternative ignition setups for the Eagle engine's sparking plugs. | 22th Apr 1915 | Box 34 \ 2 Scan083 | |
| Requesting remarks on a small, porcelain type, Hobson aero engine ignition plug. | 18th Feb 1916 | Box 34 \ 2 Scan084 | |
| Unsatisfactory performance of ignition plugs for aero engines. | 18th Feb 1916 | Box 34 \ 2 Scan085 | |
| Potential solutions for sparking plug overheating, including suggestions from Mr. Royce. | 9th Sep 1916 | Box 34 \ 2 Scan086 | |
| Letter discussing the 'B' Eagle engine, focusing on ignition plug improvements after a 24-hour test run. | 11th Sep 1916 | Box 34 \ 2 Scan087 | |
| Spark plug insulation materials, fixing methods, and alternative washer suggestions for engine testing. | 15th May 1916 | Box 34 \ 2 Scan088 | |
| From 'R' to 'Hs' requesting a photostat copy of an enclosed sketch for Mr. Hives. | 15th Feb 1916 | Box 34 \ 2 Scan089 | |
| Experiment for an ignition plug firing in a pocket. | 22th Sep 1916 | Box 34 \ 2 Scan090 | |
| Follow-up letter from chemical engineers Guthrie & Co. regarding a lack of response on a sparking plug proposal. | 10th Aug 1917 | Box 34 \ 2 Scan091 | |
| The testing, repair and performance of a 260 HP Mercedes engine, including power curve data and spark plug analysis. | 10th Dec 1917 | Box 34 \ 2 Scan092 | |
| Analysis of engine performance, focusing on spark plug placement, compression ratios, and induction, comparing against a Mercedes engine. | 10th Dec 1917 | Box 34 \ 2 Scan093 | |
| Letter proposing a newly designed aero sparking plug. | 7th Apr 1918 | Box 34 \ 2 Scan094 | |
| Unreliability of sparking plugs and test methods to observe failure modes in 'Eagle' cylinders. | 8th May 1918 | Box 34 \ 2 Scan095 | |
| Technical report on the performance of various spark plugs, observing their temperature characteristics and pre-ignition points. | 8th May 1918 | Box 34 \ 2 Scan096 | |
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