| Description | Date | Identifier | |
| Report analysing lost pedal movement in a rear braking system, including a table of deflection measurements and a blueprint of the linkage. | 28th Jan 1927 | Box 15 \ 2 Scan007 | |
| Test report comparing pedal travel lost in the rear axle linkage for the 40/50 HP and EAC.V11 car models. | 28th Jan 1927 | Box 15 \ 2 Scan008 | |
| Test report on the flexibility and twist of the EAC.Vll axle under braking torque, including data on lost movement due to elasticity. | 28th Jan 1927 | Box 15 \ 2 Scan009 | |
| Diagram illustrating axle torsional movement and its effect on brake pedal travel. | 23th Dec 1927 | Box 15 \ 2 Scan010 | |
| Drawings for the arrangement of clutch and brake pedals, and alternative schemes for the clutch pedal stop. | 23th Dec 1927 | Box 15 \ 2 Scan011 | |
| Revised pedal support, awaiting comments before further detailing. | 15th Feb 1928 | Box 15 \ 2 Scan012 | |
| Centralised chassis lubrication for the front brake differential shaft, pedals, and clutch operating shaft. | 26th May 1928 | Box 15 \ 2 Scan013 | |
| Modifications for 'E' type steering on the G.2.B. series Phantom. | 14th Jun 1928 | Box 15 \ 2 Scan014 | |
| The design of 'SS' pedals, cancelling the 'B' type and proposing new 'C' type pedals. | 28th Aug 1928 | Box 15 \ 2 Scan015 | |
| Query regarding the reduction in diameter of a foot pedal stem and concerns about material hardness after brazing. | 6th Nov 1928 | Box 15 \ 2 Scan016 | |
| Alignment of the S.S. chassis pedals with the 20 HP chassis, noting material and dimension considerations. | 6th Nov 1928 | Box 15 \ 2 Scan017 | |
| Requesting particulars of the steering and pedals for experimental cars 21-EX, 22-EX, and 23-EX. | 12th Nov 1928 | Box 15 \ 2 Scan018 | |
| Changes to the 'SS' Bijur lubrication system, specifically for the accelerator pedal and oil pipes. | 28th Nov 1928 | Box 15 \ 2 Scan019 | |
| Poor braking on car 18-EX, questioning if changes were made to the leverages. | 4th Dec 1928 | Box 15 \ 2 Scan020 | |
| Proposal to adopt the 20 HP pedal mounting for the Phantom II to resolve clutch pedal issues and standardize parts. | 28th Apr 1930 | Box 15 \ 2 Scan021 | |
| Seating positions, cushion dimensions, and pedal adjustments for different driver sizes. | 29th May 1930 | Box 15 \ 2 Scan022 | |
| Modifications made to the 'F' type pedals for the continental car 26-EX. | 14th Jun 1930 | Box 15 \ 2 Scan023 | |
| Modifications and testing of adjustable pedals for the R.H. P.2 model. | 17th Jun 1930 | Box 15 \ 2 Scan024 | |
| Tests of completed cars, specifically regarding an issue with bending P.2 pedal stems and a proposed improvement. | 26th Jun 1930 | Box 15 \ 2 Scan025 | |
| Extract from a report on tests of completed cars, detailing an experimental increase in pedal stem diameter. | 5th Jul 1930 | Box 15 \ 2 Scan026 | |
| Inquiry requesting the state of progress for three experiments concerning adjustable pedal stems and bonnet modifications. | 11th Oct 1930 | Box 15 \ 2 Scan027 | |
| Replying to a query about the status of experiments on pedal stems, bonnet hinges, and bonnet modifications. | 13th Oct 1930 | Box 15 \ 2 Scan028 | |
| Standardisation of chassis parts, specifically adjustable pedal stems. | 18th Oct 1930 | Box 15 \ 2 Scan029 | |
| Standardisation form for chassis part X M 470, detailing alterations, costs, and required approvals. | 30th Oct 1930 | Box 15 \ 2 Scan030 | |
| Standardisation of adjustable pedals for P.2 'OZ' Series and confirming no design for the 20/25 HP. | 20th Jul 1931 | Box 15 \ 2 Scan031 | |
| Investigating a complaint about noise caused by pedal movement from the Diamond engine mounting and proposing solutions. | 24th Nov 1931 | Box 15 \ 2 Scan032 | |
| Query regarding the stiffness and steadiness of the pedals and wheel carrier on the 20-EX Chassis. | 6th Apr 1932 | Box 15 \ 2 Scan033 | |
| Excessive fidgeting of the new canti-lever clutch pedal and the proposed solution. | 17th Jun 1932 | Box 15 \ 2 Scan034 | |
| Optimising the clutch pedal angle, noting differences between the L.H. and R.H. chassis. | 18th Jun 1932 | Box 15 \ 2 Scan035 | |
| Modification to the Phantom II clutch pedal to give greater separation, including a reference to a blueprint. | 23th Jun 1932 | Box 15 \ 2 Scan036 | |
| Standardisation of a clutch pedal with a spring washer and collar fitted to the bearing. | 12th Aug 1932 | Box 15 \ 2 Scan037 | |
| Standardisation document for chassis parts concerning the petrol filler cap and boot dust proofing. | 12th Sep 1938 | Box 15 \ 2 Scan038 | |
| From Mr. Royce requesting the fitting of the latest type flexible skirt pistons to specific chassis. | 30th Dec 1925 | Box 15 \ 3 Scan001 | |
| Flexibility test performed on pedestal pistons compared to standard pistons. | 12th Oct 1926 | Box 15 \ 3 Scan002 | |
| Piston flexibility tests, including a diagram of the test rig and a table of results. | 10th Oct 1927 | Box 15 \ 3 Scan003 | |
| Test report on a Phantom engine investigating the relationship between piston friction and overrun vibrations. | 10th Oct 1927 | Box 15 \ 3 Scan004 | |
| Drawings for 'Y' metal pistons for EAC.10 and 14. | 28th Nov 1927 | Box 15 \ 3 Scan005 | |
| Use of EAC.10 & 14 die-cast pistons for production and sporting Phantom models. | 29th Nov 1927 | Box 15 \ 3 Scan006 | |
| Piston pin lubrication methods and suggesting experimental modifications. | 9th Dec 1927 | Box 15 \ 3 Scan007 | |
| From E. to B.J. Hs. regarding Mr. Royce's requested modifications to a cross web piston design. | 13th Dec 1927 | Box 15 \ 3 Scan008 | |
| Trialling sand cast pistons made from Hall's Special Alloy for the 12-EX and a bench test engine. | 26th Jan 1928 | Box 15 \ 3 Scan009 | |
| Comparing cross web and diagonal web piston designs, concluding the diagonal web piston is the superior design for car work. | 18th Feb 1928 | Box 15 \ 3 Scan010 | |
| Recommending a material change for piston pins from casehardened steel to high duty alloy steel. | 15th Mar 1928 | Box 15 \ 3 Scan011 | |
| The material properties and fatigue testing of piston pins for aero and car engines. | 4th Jul 1928 | Box 15 \ 3 Scan012 | |
| Two types of pistons for a 10,000-mile Phantom engine test. | 1st May 1928 | Box 15 \ 3 Scan013 | |
| Single bolt pedestal pistons with a lower scraper ring for Phantom and EAC.10 models. | 1st May 1928 | Box 15 \ 3 Scan014 | |
| Design and development of new experimental 20 HP pistons, including a novel design with an invar ring. | 20th Jul 1928 | Box 15 \ 3 Scan015 | |
| Modifications to Phantom piston rings to increase cylinder wall pressure. | 23th Jul 1928 | Box 15 \ 3 Scan016 | |
| From Royce to Hives regarding piston ring solutions for Twenty HP and Phantom models. | 23th Jul 1928 | Box 15 \ 3 Scan017 | |
| Telegram suggesting engine modifications, including specific types of rings and altered oil grooves in bearings. | 23th Jul 1926 | Box 15 \ 3 Scan018 | |
| Telegram concerning piston rings for the 20 horsepower and Phantom models. | 23th Jul 1928 | Box 15 \ 3 Scan019 | |
| Post Office Telegraph form with a handwritten message from Royce. | 23th Jul 1928 | Box 15 \ 3 Scan020 | |
| Fitting and testing pistons and rings for the 20 HP and Phantom engines. | 25th Jul 1928 | Box 15 \ 3 Scan021 | |
| Requesting a set of 'Perfect Circle' piston rings for a Phantom engine, with a preference for a 45° joint. | 31th Aug 1928 | Box 15 \ 3 Scan022 | |
| Running experience and performance issues of single bolt pedestal pistons, specifically concerning piston knock and gas leakage. | 12th Oct 1928 | Box 15 \ 3 Scan023 | |
| Engine lubrication, seizure risks after cold starts, and piston design improvements. | 12th Oct 1928 | Box 15 \ 3 Scan024 | |
| The optimal number of piston rings to prevent blow past and a proposal for a new piston design test. | 10th Oct 1928 | Box 15 \ 3 Scan025 | |
| Design and specifications for pistons and their rings. | 10th Oct 1928 | Box 15 \ 3 Scan026 | |
| Specification document detailing the features and dimensions of pistons for the Phantom and 20 HP chassis. | 2nd Nov 1928 | Box 15 \ 3 Scan027 | |
| Testing of two different piston types for the 'SS' engine. | 2nd Nov 1928 | Box 15 \ 3 Scan028 | |
| Modifications for the G.4 engine crankcase and 4-point mounting. | 23th Apr 1929 | Box 15 \ 3 Scan029 | |
| Piston knocks in F.2-B series engines, attributing the cause to temporary piston seizure from lack of lubrication on cold starts. | 30th Apr 1929 | Box 15 \ 3 Scan030 | |
| The design objectives and features of SS. Invar Strut Pistons. | 27th Jun 1929 | Box 15 \ 3 Scan031 | |
| Modification to S.S. pistons, lengthening the skirt by .375 inches to resolve issues with piston slap. | 12th Jul 1929 | Box 15 \ 3 Scan032 | |
| Car with defective pistons sent for repair and feedback on the performance of a 20 HP engine. | 16th Jul 1929 | Box 15 \ 3 Scan033 | |
| Inquiring about the production status of various car pistons. | 17th Sep 1929 | Box 15 \ 3 Scan034 | |
| Report outlining the designs and features of various car pistons. | 4th Oct 1929 | Box 15 \ 3 Scan035 | |
| Specifications and features for various piston designs, detailing alterations, ring arrangements, and gudgeon pin fixings. | 16th Jul 1928 | Box 15 \ 3 Scan036 | |
| The test results of Invar pistons on a Phantom 11 engine. | 13th Nov 1929 | Box 15 \ 3 Scan037 | |
| Order for a set of Phantom pistons with two spares, specifying magnesium instead of aluminium. | 3rd Dec 1929 | Box 15 \ 3 Scan038 | |
| Test bed running and clearances for Invar pistons in a Phantom II engine. | 27th Dec 1929 | Box 15 \ 3 Scan039 | |
| Clearances and hot testing procedures for pads on a test bed. | 24th Dec 1929 | Box 15 \ 3 Scan040 | |
| Blueprint showing a cross-section of a piston with an Invar strut, indicating where it tightens in the bore. | 24th Dec 1929 | Box 15 \ 3 Scan041 | |
| Test bed results for Phantom II Invar pistons, detailing issues with clearances and cold knocks. | 15th Jan 1930 | Box 15 \ 3 Scan042 | |
| Piston design, comparing issues with standard aluminium and cast iron pistons, and the need for flexibility. | 23th Jan 1930 | Box 15 \ 3 Scan043 | |
| Modifying Phantom II Invar pistons to introduce flexibility for a better fit. | 23th Jan 1930 | Box 15 \ 3 Scan044 | |
| The satisfactory testing of pistons made from R.R.53 material for Phantom II and 20/25 HP models, requesting a new standardisation sheet. | 2nd Sep 1930 | Box 15 \ 3 Scan045 | |
| Questioning the standardisation of pistons made in RR.50 alloy without a 10,000-mile test. | 29th Sep 1930 | Box 15 \ 3 Scan046 | |
| The decision to production test pistons made from R.R.50 alloy. | 3rd Oct 1930 | Box 15 \ 3 Scan047 | |
| Standardisation of chassis parts, proposing a change of piston material from alloy No. 221 to RR. 53. | 4th Sep 1930 | Box 15 \ 3 Scan048 | |
| Proposing an increase in the dimensions of Phantom II pistons to combat 'cold knocks' and extend piston life. | 29th Dec 1930 | Box 15 \ 3 Scan049 | |
| Redesign of the P.2 piston by increasing its length and testing a new design. | 10th Jan 1931 | Box 15 \ 3 Scan050 | |
| Short memo forwarding a note from Mx and proposing a test for an item with more bearing area. | 14th Jan 1931 | Box 15 \ 3 Scan051 | |
| Quarterly complaints regarding Phantom II pistons, suggesting an increase in piston length. | 5th Jan 1931 | Box 15 \ 3 Scan052 | |
| Longer experimental pistons for the P. 2. model, with illustrations and design suggestions. | 20th Jan 1931 | Box 15 \ 3 Scan053 | |
| Testing longer pistons for the Phantom II engine to address piston 'slap'. | 1st Apr 1931 | Box 15 \ 3 Scan054 | |
| Asking about the severity of piston knocks on the Phantom II and if extra oil would help. | 16th Apr 1931 | Box 15 \ 3 Scan055 | |
| Customer complaints and potential solutions for piston knock and brake squeaks on Phantom II cars. | 21th Apr 1931 | Box 15 \ 3 Scan056 | |
| Issues and modifications concerning the clutch, front shock dampers, and high tension wires. | 21th Apr 1931 | Box 15 \ 3 Scan057 | |
| Standardisation proposal for a longer skirt piston to safeguard against piston knocks. | 17th Apr 1931 | Box 15 \ 3 Scan058 | |
| Merits and proposed changes to the practice of pinning piston rings for aero and car engines. | 24th May 1932 | Box 15 \ 3 Scan059 | |
| 19-EX piston failures due to breaking piston stops and rapid ring wear at high speeds. | 1st Jul 1932 | Box 15 \ 3 Scan060 | |
| Experimental piston with stiffer rings for a Phantom II chassis. | 8th Jul 1932 | Box 15 \ 3 Scan061 | |
| Potential causes and investigations into piston failure. | 14th Jul 1932 | Box 15 \ 3 Scan062 | |
| Limitations of chassis engine pistons with spring skirts and proposing design improvements. | 11th May 1933 | Box 15 \ 3 Scan063 | |
| Modifications to a Phantom Piston, including a change to Staybrite steel for the stops. | 21th Apr 1934 | Box 15 \ 3 Scan064 | |
| Standardisation of parts for the 40/50 model, specifically deleting stops for scraper rings on pistons. | 16th Oct 1934 | Box 15 \ 3 Scan065 | |
| Standardisation of parts form detailing costs for extra jigs and tools for the 'U' series chassis. | 20th Oct 1934 | Box 15 \ 3 Scan066 | |
| Revised dashboard design, changing from a sheet metal construction to a casting for 'B' steering. | 8th Jan 1926 | Box 15 \ 4 Scan001 | |
| Use of a Mechanic's joint from the USA for the EAC.7 propeller shaft. | 2nd Feb 1926 | Box 15 \ 4 Scan002 | |
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