| Description | Date | Identifier | |
| Introduction of a new steel for exhaust valves in all chassis and aero engines. | 30th Jul 1929 | Box 66 \ 2 scan0324 | |
| Internal correspondence regarding a complaint about exhaust manifolds. | 6th Jan 1931 | Box 66 \ 2 scan0325 | |
| Consistent failures of the Phantom I exhaust manifold and a proposed new design. | 16th Jan 1931 | Box 66 \ 2 scan0326 | |
| Design and issues with exhaust pipes, proposing alternative solutions. | 4th Mar 1931 | Box 66 \ 2 scan0327 | |
| Hand-drawn sketch of a vehicle frame section with annotations. | 22th Jul 1931 | Box 66 \ 2 scan0328 | |
| Requesting the supply of modified exhaust manifolds for testing. | 22th Jul 1931 | Box 66 \ 2 scan0329 | |
| Cracked exhaust manifolds on Phantom I & 20 HP models, seeking customer cars to test modifications. | 22th Jul 1931 | Box 66 \ 2 scan0330 | |
| Fitting of modified exhaust manifolds on Phantom I & II models to address cracking issues. | 28th Jul 1931 | Box 66 \ 2 scan0331 | |
| Sending various experimental Phantom I and 20 HP exhaust manifolds for testing on customer cars. | 4th Sep 1931 | Box 66 \ 2 scan0332 | |
| Requesting a progress report on the testing of experimental modified exhaust manifolds for Phantom I and 20 HP cars. | 2nd Oct 1931 | Box 66 \ 2 scan0333 | |
| Status of fitting experimental modified exhaust manifolds to two specific vehicles. | 6th Oct 1931 | Box 66 \ 2 scan0334 | |
| Testing of exhaust manifold modifications on customer cars. | 9th Oct 1931 | Box 66 \ 2 scan0335 | |
| Quarterly complaints memo about cracked exhaust manifolds on Phantom I & 20 HP models, seeking cars for testing modified parts. | 22th Jul 1931 | Box 66 \ 2 scan0336 | |
| Quarterly complaints of cracked exhaust manifolds on Phantom I & P.2 models. | 28th Jul 1931 | Box 66 \ 2 scan0337 | |
| The dispatch of experimental Phantom I and 20 HP exhaust manifolds for testing. | 4th Sep 1931 | Box 66 \ 2 scan0338 | |
| Request for information and progress reports on tests of experimental modified exhaust manifolds for P.I. and 20 HP cars. | 2nd Oct 1931 | Box 66 \ 2 scan0339 | |
| The progress of fitting experimental modified exhaust manifolds to a Phantom 1 and another customer's car. | 6th Oct 1931 | Box 66 \ 2 scan0340 | |
| Design, alterations, and testing of exhaust manifolds for various chassis models. | 3rd Oct 1931 | Box 66 \ 2 scan0341 | |
| Inquiry about the progress of tests on modified P.I. and 20 HP exhaust manifolds. | 2nd Nov 1931 | Box 66 \ 2 scan0342 | |
| Status report on the trial of experimental modified manifolds on various customer cars. | 6th Nov 1931 | Box 66 \ 2 scan0343 | |
| Quarterly complaints of cracked exhaust manifolds and the decision to issue modified replacements. | 8th Nov 1931 | Box 66 \ 2 scan0344 | |
| Clarifying the suitability of experimental malleable iron exhaust manifolds for various chassis, correcting a previous statement. | 23th Nov 1931 | Box 66 \ 2 scan0345 | |
| Letter discussing a broken exhaust manifold and choke valve issues on chassis 63-EF, proposing an experimental solution. | 30th Dec 1931 | Box 66 \ 2 scan0346 | |
| Use of a sliding joint manifold to remedy broken manifolds caused by extreme heat on Chassis 63-EF. | 30th Dec 1931 | Box 66 \ 2 scan0347 | |
| Experimental modified exhaust manifolds, replacement strategies, and despatch of new parts. | 1st Jan 1932 | Box 66 \ 2 scan0348 | |
| Issue of heat in the floorboards and recommending the use of bonnets with shutters for cooling. | 7th Jul 1914 | Box 66 \ 3 scan0001 | |
| Difficulty with the front bonnet clip and a proposed solution by Mr. Royce. | 30th May 1919 | Box 66 \ 3 scan0002 | |
| Modifications to the front bonnet catch for easier operation as requested by Mr. Royce. | 30th May 1919 | Box 66 \ 3 scan0003 | |
| Bonnet catch clearance issue on chassis 7 CA and requesting revised parts for trial. | 25th Oct 1918 | Box 66 \ 3 scan0004 | |
| Value of bonnet air shutters and the design of the bonnet opening mechanism. | 3rd Jun 1919 | Box 66 \ 3 scan0005 | |
| The design and necessity of radiator shutters and bonnets for the 40/50 chassis. | 5th Jun 1919 | Box 66 \ 3 scan0006 | |
| Recommendation to alter the position of the bonnet stud handles to make them easier to lift. | 5th Jun 1919 | Box 66 \ 3 scan0007 | |
| Extract detailing the assembly parts list for chassis 1.E.X. | 30th Jun 1919 | Box 66 \ 3 scan0008 | |
| Requesting consideration of a modified, less expensive design for the sliding doors on the 40/50 chassis bonnet. | 30th Jun 1919 | Box 66 \ 3 scan0009 | |
| The decision not to fit louvres to standard chassis bonnets, considering sliding doors or shutters as a more expensive alternative. | 30th Jun 1919 | Box 66 \ 3 scan0010 | |
| Print of 'N' Scheme 76, covering modifications to front bonnet catches and fasteners. | 18th Jul 1919 | Box 66 \ 3 scan0011 | |
| Directive from Mr. Royce to change the material of the bonnet ledge on the dash from steel to nickel silver. | 21th Aug 1919 | Box 66 \ 3 scan0012 | |
| Repositioning of bonnet clips closer together as suggested by Mr. Royce. | 26th Aug 1919 | Box 66 \ 3 scan0013 | |
| Alteration to change the material of bonnet angle irons from Mild Steel to Nickel Silver for experimental purposes. | 1st Aug 1919 | Box 66 \ 3 scan0014 | |
| Accompanying blueprints for 'N' Scheme 117, detailing a new position for bonnet catches and requesting a trial fitment. | 9th Sep 1919 | Box 66 \ 3 scan0015 | |
| Notes from a meeting discussing a design change for the 40/50 HP radiator. | 24th Oct 1919 | Box 66 \ 3 scan0016 | |
| List of blueprints for a bonnet and radiator modification, 1 inch higher than standard. | 15th Nov 1919 | Box 66 \ 3 scan0017 | |
| Providing the experimental number for a bonnet and radiator that is 1 inch higher than standard. | 18th Nov 1919 | Box 66 \ 3 scan0018 | |
| List of parts to be fitted to a chassis for a 10,000-mile test run. | 19th Nov 1919 | Box 66 \ 3 scan0019 | |
| Delay in manufacturing L, M, and N series radiators due to required design alterations for the water outlet pipe and bottom tank. | 26th Nov 1919 | Box 66 \ 3 scan0020 | |
| Suggestions for bonnet anti-rattle packing and a new thief-proof locking system. | 2nd Dec 1919 | Box 66 \ 3 scan0021 | |
| Decision on incorporating a higher bonnet and dashboard on the American chassis is pending the completion of chassis 4.EX. | 22th Jan 1920 | Box 66 \ 3 scan0022 | |
| Request to create a model for a top water pipe for the 40/50 Chassis related to raising the radiator, with blueprints provided. | 2nd Feb 1920 | Box 66 \ 3 scan0023 | |
| Blueprints for an urgent experimental outlet pipe thermostat to radiator set. | 2nd Feb 1920 | Box 66 \ 3 scan0024 | |
| Extract about a visit to West Wittering with chassis 4.EX to showcase a thermostat regulator and a higher bonnet. | 28th Feb 1920 | Box 66 \ 3 scan0025 | |
| Coachbuilder's drawing for Fairey & Charles, noting an alteration to the radiator and bonnet height. | 15th Mar 1920 | Box 66 \ 3 scan0026 | |
| Security flaw in the bonnet locks which can be opened through the shutters and proposes a solution. | 15th Mar 1920 | Box 66 \ 3 scan0027 | |
| Design modification for bonnet shutter locks to improve security. | 20th Mar 1920 | Box 66 \ 3 scan0028 | |
| Extract concerning a chassis fitted with a radiator and bonnet raised 1 inch higher than standard. | 17th Mar 1920 | Box 66 \ 3 scan0029 | |
| Urging the quick finalisation of a standardisation sheet for a higher dashboard and bonnet. | 16th Mar 1920 | Box 66 \ 3 scan0030 | |
| Standardisation of chassis parts to raise the radiator and bonnet by one inch. | 18th Mar 1920 | Box 66 \ 3 scan0031 | |
| Proposal to raise the dash-board, radiator, and bonnet on the 4-EX chassis. | 25th Mar 1920 | Box 66 \ 3 scan0032 | |
| Modifications to the height of the dash-board, radiator, and bonnet for a chassis. | 25th Mar 1920 | Box 66 \ 3 scan0033 | |
| Standardisation sheet regarding the radiator and bonnet being raised 1' higher than standard. | 26th Mar 1920 | Box 66 \ 3 scan0034 | |
| 1-inch higher radiator and bonnet on the 4-EX chassis. | 27th Mar 1920 | Box 66 \ 3 scan0035 | |
| Use of a smaller windscreen and the proportional appearance of the car's bonnet. | 20th Mar 1920 | Box 66 \ 3 scan0036 | |
| Increasing the height of the dashboard, radiator, and bonnet for a Pullman Limousine. | 27th Mar 1920 | Box 66 \ 3 scan0037 | |
| Design complaints and potential improvements for car bodies and bonnets. | 8th Jan 1920 | Box 66 \ 3 scan0038 | |
| Proposal to raise the radiator and bonnet height by one inch, with feedback from coachbuilders. | 27th Mar 1920 | Box 66 \ 3 scan0039 | |
| Design points for car bodies, addressing complaints about touring bodies being too low and bonnet proportions. | 27th Mar 1920 | Box 66 \ 3 scan0040 | |
| Complaint and instruction regarding faulty bonnet locks and bonnet fitting clearance. | 26th Apr 1920 | Box 66 \ 3 scan0041 | |
| Requesting an experimental bonnet ledge in Nickel Silver for the 40/50 Chassis. | 9th Jun 1920 | Box 66 \ 3 scan0042 | |
| Previous and second instructions for the 40/50 chassis bonnet ledge on the dash. | 17th Jun 1920 | Box 66 \ 3 scan0043 | |
| List of experimental parts fitted to chassis 6.EX. | 22th Jun 1920 | Box 66 \ 3 scan0044 | |
| The inspection of chassis 6.EX, detailing observations on various components. | 17th Jul 1920 | Box 66 \ 3 scan0045 | |
| Decision to make bonnet locks an optional extra and the availability of Gibbon and Yale lock types. | 22th Jul 1920 | Box 66 \ 3 scan0046 | |
| Standardisation of Yale locks as bonnet fittings. | 24th Jul 1920 | Box 66 \ 3 scan0047 | |
| Agreeing to fit Yale locks of the best quality on all bonnets. | 20th Jul 1920 | Box 66 \ 3 scan0048 | |
| Decision to cancel bonnet locks as a standard fitting and the choice of lock supplier. | 22th Jul 1920 | Box 66 \ 3 scan0049 | |
| Examining Yale Locks for bonnets before standardising them. | 28th Jul 1920 | Box 66 \ 3 scan0050 | |
| Fitting of Yale locks on bonnets and comparing them to Gibbon locks. | 30th Jul 1920 | Box 66 \ 3 scan0051 | |
| Discussion and request for a design alteration to raise the bonnet and dash by one inch. | 14th Oct 1920 | Box 66 \ 3 scan0052 | |
| Proposal to fit a 1-inch higher dashboard to a chassis intended for a Hooper Landaulet body. | 22th Jul 1920 | Box 66 \ 3 scan0053 | |
| Dimensioned drawing of a dashboard component with angular measurements. | 14th Oct 1907 | Box 66 \ 3 scan0054 | |
| Corrected sketch for a 2' higher dashboard and coordinating the fitting of an unpolished instrument board. | 3rd Nov 1920 | Box 66 \ 3 scan0055 | |
| Proposal to modify the mounting position for the radiator bottom water pipe clip on the 40/50 HP chassis. | 18th Oct 1928 | Box 66 \ 3 scan0056 | |
| Specifications and arrangements for an experimental car being sent to the U.S.A. for winter testing. | 4th Nov 1920 | Box 66 \ 3 scan0057 | |
| Agreement to pay an extra charge for altering the scuttle for a higher dashboard on an experimental landaulet. | 8th Nov 1920 | Box 66 \ 3 scan0058 | |
| Testing suggestions for bonnet catches. | 19th Nov 1920 | Box 66 \ 3 scan0059 | |
| Letter from the American branch proposing a modification to the bonnet catches to prevent rattles and improve ease of lifting. | 29th Oct 1920 | Box 66 \ 3 scan0060 | |
| Report from an American visit detailing component issues and requests for bonnets, radiators, locks, and battery boxes. | 11th Nov 1920 | Box 66 \ 3 scan0061 | |
| Points of interest from a visit to America, covering ignition, magnetos, wiring, and other components. | 1st Nov 1920 | Box 66 \ 3 scan0062 | |
| The necessity of designing better bonnet lifting handles due to the upcoming removal of sliding shutters. | 5th Jan 1921 | Box 66 \ 3 scan0063 | |
| Experimental modification to the 40/50 Chassis bonnet to reduce weight and cost. | 6th Apr 1921 | Box 66 \ 3 scan0064 | |
| Customer complaints from Australia regarding bonnet rattles and recommending a return to the old louvred bonnet design. | 17th Aug 1921 | Box 66 \ 3 scan0065 | |
| Following up on the issue of bonnet rattles. | 5th Sep 1921 | Box 66 \ 3 scan0066 | |
| The policy of deleting doors on the bonnet to resolve rattling complaints. | 9th Sep 1921 | Box 66 \ 3 scan0067 | |
| Engine overheating and water boiling issues in the Swiss Alps, with suggestions for high compression engines. | 14th Oct 1921 | Box 66 \ 3 scan0068 | |
| Use of a sand-blasted finish on aluminium bonnets to reduce glare while retaining the metal's appearance. | 6th Dec 1921 | Box 66 \ 3 scan0069 | |
| Difficulty in lifting the 40/50 bonnet and a proposed solution to fit Goshawk handles. | 9th Jun 1922 | Box 66 \ 3 scan0070 | |
| Suggestion to improve the 40/50 Chassis 'R' Series bonnet with new fixings, handles and locks. | 27th Oct 1922 | Box 66 \ 3 scan0071 | |
| Standardisation document for fitting handles to bonnets for convenient lifting. | 19th Sep 1922 | Box 66 \ 3 scan0072 | |
| Standardisation of chassis parts by fixing the radiator 1 inch higher to improve coachwork. | 21th Mar 1923 | Box 66 \ 3 scan0073 | |
| Cost implications of fixing the radiator 1 inch higher. | 11th Apr 1923 | Box 66 \ 3 scan0074 | |
| Using a non-oxidising aluminium alloy for bonnets and undershields for 20 HP and 40/50 models. | 9th Sep 1923 | Box 66 \ 3 scan0075 | |
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