| Description | Date | Identifier | |
| Service department notice detailing recommended modifications for pre-F.A.O. 1500 type Falcon engines during repair. | 18th Oct 1928 | Box 10 \ 3 03-page094 | |
| Proposed modifications to Wraith Bottom Tappets. | 10th Nov 1937 | Box 10 \ 3 03-page095 | |
| Blueprints for a new Valve Spring with Damper for the Wraith III model. | 9th Dec 1937 | Box 10 \ 3 03-page097 | |
| Extremely faded and illegible typed document. | 31th Dec 1937 | Box 10 \ 3 03-page098 | |
| The 3.B.A. location screw in the rocker shaft coming loose on Wraith, Bentley & 30 HP models. | 31th Dec 1937 | Box 10 \ 3 03-page099 | |
| Thermal lock seizure tests comparing R.R.56 alloy and cast iron exhaust valve guides. | 15th Sep 1937 | Box 10 \ 3 03-page100 | |
| Proposal for a trial of venturi-shaped inlet valve throats on a Wraith engine. | 4th Jan 1938 | Box 10 \ 3 03-page101 | |
| Proposal for a new supercharger drive for the P.V. 12 engine. | 11th Mar 1928 | Box 10 \ 3 03-page102 | |
| Requesting the trial of venturi-shaped inlet valve throats on a Wraith cylinder head. | 6th Jan 1938 | Box 10 \ 3 03-page103 | |
| Modification to the Wraith III spring drive unit by adding holes to the damper. | 11th Jan 1938 | Box 10 \ 3 03-page105 | |
| The document is too faded and illegible to determine its specific content. | 13th Jan 1938 | Box 10 \ 3 03-page106 | |
| Investigation into push rod vibration on the Wraith III valve gear and the proposed solution. | 13th Jan 1938 | Box 10 \ 3 03-page107 | |
| Recommendation for a pneumatic brake system layout to prevent failures from moisture accumulation. | 23th Nov 1938 | Box 10 \ 3 03-page108 | |
| New drawing for an increased diameter push rod for the Wraith III Chassis. | 17th Jan 1938 | Box 10 \ 3 03-page109 | |
| Request for aircraft details to discuss radiator and oil cooling systems for a Condor engine installation. | 22th Apr 1924 | Box 10 \ 3 03-page110 | |
| Modification to the Wraith III and B.III units concerning tappet drain holes. | 19th Jan 1938 | Box 10 \ 3 03-page111 | |
| Instructions for a series of modifications to be made to 100 sets of parts for the Wraith III engine. | 3rd Feb 1938 | Box 10 \ 3 03-page113 | |
| The content of the document is illegible due to the poor quality of the image. | 7th Feb 1938 | Box 10 \ 3 03-page114 | |
| Drawing modification for Wraith and Bentley III Bottom Tappets to prevent push rod jamming. | 7th Feb 1938 | Box 10 \ 3 03-page115 | |
| The manufacture of trial springs for a Wraith III, detailing specific dimensions. | 11th Feb 1938 | Box 10 \ 3 03-page117 | |
| Investigation into exhaust valve stretch and the subsequent fitting of new valves and springs. | 3rd Mar 1938 | Box 10 \ 3 03-page119 | |
| Specification sheet outlining a colour-coded stamping system for production drawings to indicate process control methods for sub-producers. | 18th Feb 1919 | Box 10 \ 3 03-page120 | |
| Instructions for machining newly forged Wraith III inlet valves from The Belgrave Engineering Co. | 10th Mar 1938 | Box 10 \ 3 03-page121 | |
| Required poundage for the Wraith spring drive damper and requesting new, weakened springs for trial. | 31th Mar 1938 | Box 10 \ 3 03-page123 | |
| Typed document that is too degraded to be read. | 6th Apr 1938 | Box 10 \ 3 03-page124 | |
| Cancelling a previous instruction and updating the poundage setting for the Wraith spring drive damper. | 6th Apr 1938 | Box 10 \ 3 03-page125 | |
| Cost reduction exercise for Wraith rocker cover nuts, replacing standard nuts and springs with nickel-deposited nuts and neoprene rubbers. | 20th May 1938 | Box 10 \ 3 03-page127 | |
| Air Ministry's conditional approval for the 'F' type engine following type testing. | 25th Oct 1928 | Box 10 \ 3 03-page128 | |
| Wraith engine slow running issues after road use, with production recommendations. | 27th May 1938 | Box 10 \ 3 03-page129 | |
| Analysis of valve seat warping in different engine heads and proposed trials for a solution. | 26th May 1938 | Box 10 \ 3 03-page131 | |
| Technical report on the warping of valve seats in Wraith III and Bentley cylinder heads. | 26th May 1938 | Box 10 \ 3 03-page133 | |
| The document is completely illegible due to the poor quality of the image. | 26th May 1938 | Box 10 \ 3 03-page134 | |
| Placeholder page for a drawing, marked with a large X. | 31th Aug 1937 | Box 10 \ 3 03-page135 | |
| Design for modified rockers for the Wraith III engine, detailing changes to achieve a .350 valve lift. | 31th Aug 1937 | Box 10 \ 3 03-page136 | |
| Blank page from the archive with no visible content. | 31th Aug 1937 | Box 10 \ 3 03-page137 | |
| Placeholder page with the word 'Drawing' handwritten at the top and a large 'X' drawn below. | 27th May 1938 | Box 10 \ 3 03-page138 | |
| Comparison of the metal section between valves on the 25/30, Wraith & Bentley II models. | 27th May 1938 | Box 10 \ 3 03-page139 | |
| Agreeing to use small valves for the Wraith III as a design compromise. | 20th Jun 1938 | Box 10 \ 3 03-page141 | |
| Tests concerning the warping of valve seats for the Wraith III cylinder heads. | 20th Jun 1938 | Box 10 \ 3 03-page143 | |
| Recommendation on exhaust and inlet valve sizes to improve valve seat warpage. | 20th Jun 1938 | Box 10 \ 3 03-page145 | |
| With illegible text. | 1st Jun 1938 | Box 10 \ 3 03-page146 | |
| Power curve graph for a Bentley III engine, showing B.HP and B.M.E.P. against R.P.M. for various valve configurations. | 1st Jun 1938 | Box 10 \ 3 03-page147 | |
| Stamped blank page, likely the reverse side of another document. | 21th Jun 1938 | Box 10 \ 3 03-page148 | |
| Power and B.M.E.P. curve graph for a Wraith III engine, comparing various valve configurations. | 1st Jun 1935 | Box 10 \ 3 03-page149 | |
| Stamped document from the Print Room. | 21th Jun 1938 | Box 10 \ 3 03-page150 | |
| Reversion of inlet and exhaust valve diameters for the Wraith III model. | 24th Jun 1938 | Box 10 \ 3 03-page151 | |
| Badly faded and illegible typed document. | 25th Jun 1938 | Box 10 \ 3 03-page152 | |
| Instruction to correct defective grinding on valve springs supplied by The Tempered Spring Co. Ltd. | 25th Jun 1938 | Box 10 \ 3 03-page153 | |
| Valve seat warping in the Wraith III cylinder head, proposing new valve specifications for experiment. | 25th Jun 1938 | Box 10 \ 3 03-page155 | |
| Issues with push rod rubbing and considerations for cylinder head modifications. | 25th Jun 1938 | Box 10 \ 3 03-page157 | |
| Typed memorandum or report on aged, low-contrast paper with punch holes. | 1st Jun 1938 | Box 10 \ 3 03-page158 | |
| Performance graph comparing power outputs for different valve and exhaust configurations on a Bentley III engine. | 1st Jun 1938 | Box 10 \ 3 03-page159 | |
| Blank document page stamped by the Print Room. | 25th Jun 1938 | Box 10 \ 3 03-page160 | |
| Note concerning push rod clearance in the cylinder head for W.III & B.III models. | 2nd Jul 1938 | Box 10 \ 3 03-page161 | |
| Issues with tappets and push rods for the Wraith III and Bentley III engines, proposing a new design. | 13th Jul 1938 | Box 10 \ 3 03-page163 | |
| The two-spark magneto for the 40/50 HP Ghost chassis, detailing its advantages and correct sparking plug usage. | 3rd Aug 1929 | Box 10 \ 3 03-page164 | |
| Proposed alterations to engine components and their production implications. | 13th Jul 1938 | Box 10 \ 3 03-page165 | |
| Instructions for fitting an improved petrol tap lever and procedures for inspection. | 13th Jul 1938 | Box 10 \ 3 03-page166 | |
| Tappets and Push Rods for the Wraith III and Bentley III models. | 13th Jul 1938 | Box 10 \ 3 03-page167 | |
| Blank or un-imaged page. | 2nd Sep 1938 | Box 10 \ 3 03-page168 | |
| Decision on tappets and push rods for the Wraith III model. | 2nd Sep 1938 | Box 10 \ 3 03-page169 | |
| Modified valve spring washer with an oil seal for Wraith III and Bentley 111 engines. | 9th Sep 1938 | Box 10 \ 3 03-page171 | |
| The discontinuation of polishing push rods for the Wraith model due to cost and lack of benefit. | 16th Sep 1938 | Box 10 \ 3 03-page173 | |
| Typed page from a report or memorandum, the content of which is unreadable. | 22th Sep 1938 | Box 10 \ 3 03-page174 | |
| Discontinuation of polishing on Wraith III push rods to achieve a cost saving. | 22th Sep 1938 | Box 10 \ 3 03-page175 | |
| Extremely faded and illegible document. | 22th Sep 1938 | Box 10 \ 3 03-page176 | |
| Value and application of valve oil seal washers. | 22th Sep 1938 | Box 10 \ 3 03-page177 | |
| Proposed modification to the crankshaft centre bearing oil feed on Condor XI engines. | 3rd Apr 1929 | Box 10 \ 3 03-page178 | |
| Urgent internal memo requesting a comparative test on small versus large exhaust valves to investigate Wraith III valve seat failures. | 30th Sep 1938 | Box 10 \ 3 03-page179 | |
| Typed memo from March 1939, the main body of text is illegible. | 28th Mar 1939 | Box 10 \ 3 03-page180 | |
| Tests on cracked valve seats in Wraith cylinder heads. | 1st Oct 1938 | Box 10 \ 3 03-page181 | |
| Typed document that is too faint to be legible. | 1st Oct 1938 | Box 10 \ 3 03-page182 | |
| Valve seat failures on Wraith cylinder heads after various mileage and test bed conditions. | 1st Oct 1938 | Box 10 \ 3 03-page183 | |
| Test report comparing the mileage and durability of various engine configurations and components. | 1st Oct 1938 | Box 10 \ 3 03-page185 | |
| Completely illegible typed document on aged paper. | 7th Oct 1938 | Box 10 \ 3 03-page186 | |
| Conclusions from tests on Wraith valve timing, recommending erring on the side of late timing. | 7th Oct 1938 | Box 10 \ 3 03-page187 | |
| Instruction mandating the hand blasting of specific parts prior to the final plating operation. | 10th Apr 1939 | Box 10 \ 3 03-page188 | |
| Analysis of microphotographs from a cracked Wraith Cylinder Head valve seat to investigate its material structure. | 7th Oct 1939 | Box 10 \ 3 03-page189 | |
| Heavily faded and damaged typed page, with a handwritten note at the top. | 7th Oct 1939 | Box 10 \ 3 03-page190 | |
| Laboratory report showing two micrographs of a material, one unetched and the other etched with nitric acid in alcohol. | 7th Oct 1939 | Box 10 \ 3 03-page191 | |
| Blank green cover sheet or reverse side of a document. | 10th Nov 1938 | Box 10 \ 3 03-page192 | |
| Oil seal modification for the Wraith III valve spring top washer. | 10th Nov 1938 | Box 10 \ 3 03-page193 | |
| Weybridge engine tests of a 1350 HP Merlin power plant for the Beaufighter II, detailing cooling modifications to the rear cowling. | 22th Sep 1942 | Box 10 \ 3 03-page194 | |
| Proposal for an improved oil seal for the valve spring top washer on Wraith III and Bentley III models. | 10th Nov 1938 | Box 10 \ 3 03-page195 | |
| Preferred method for an oil seal for a valve spring top washer. | 8th Dec 1938 | Box 10 \ 3 03-page197 | |
| Heavily faded page of handwritten notes, with most text being illegible. | 12th Jan 1939 | Box 10 \ 3 03-page198 | |
| Standardization and production of push rods for the Wraith III and Bentley V models. | 12th Jan 1939 | Box 10 \ 3 03-page199 | |
| Report No. 2282 on experiments with engine No. 129A, testing fan/radiator effects and minimum oil pressure. | 10th Nov 1922 | Box 10 \ 3 03-page200 | |
| Request to scheme sodium-filled exhaust valves for trial on the Bentley V or Wraith. | 16th Jan 1939 | Box 10 \ 3 03-page201 | |
| Test report on an 'Avis' type revolution counter, No. 1345, confirming it passed a 100-hour test. | 28th Oct 1926 | Box 10 \ 3 03-page202 | |
| Coolant jets for the exhaust valve seats on the Wraith III and Bentley III models. | 26th Apr 1939 | Box 10 \ 3 03-page203 | |
| Blank or completely faded page with no visible content. | 1st May 1939 | Box 10 \ 3 03-page204 | |
| The failure and testing of Wraith type flat bottom tappets on a Phantom III engine. | 1st May 1939 | Box 10 \ 3 03-page205 | |
| Enclosing a copy of a letter regarding Mr. Halliday's visit to Derby to view a 'Condor' engine test. | 23th Jan 1926 | Box 10 \ 3 03-page206 | |
| Comparison of the weight and design of Phantom III and Wraith bottom tappets. | 1st Mar 1939 | Box 10 \ 3 03-page207 | |
| Arranging a date with a customer, Mr. J. G. Rose, for a gear ratio conversion on his car. | 7th Oct 1928 | Box 10 \ 3 03-page208 | |
| Tests on valve sealing washers for B.V. & Wraith III models. | 13th May 1939 | Box 10 \ 3 03-page209 | |
| Extremely faded and illegible document. | 15th May 1939 | Box 10 \ 3 03-page210 | |
| Tests on a modification to prevent oil leakage down valve stems. | 15th May 1939 | Box 10 \ 3 03-page211 | |
| Proposal to modify the engine mounting on a B.E.2 biplane using steel tubes to reduce cost and improve performance. | 26th Feb 1914 | Box 10 \ 3 03-page212 | |
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