From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Blueprint showing ground clearances for the 'Spectre' project, with a modified 3rd crossmember and a table of dimensions for different wheel and tyre sizes.
| Identifier | ExFiles\Box 95\3\ scan0093 | |
| Date | 7th May 1935 | |
| LEC4449 GROUND CLEARANCES TO SUIT 17.000 DIA RIMS 7.500 TYRES & MODIFIED 3RD CROSSMEMBER - SPECTRECodename for Phantom III SCALE = 1/4 & 1/1 Labels on drawing: MIN. TANK FILLED C OF N.6 CYLINDERS LEVEL TOP OF FRAME BACK OF DASH C OF TRANSMISSION LN 41.2371 (1.23.16) GROUND MAXIMUM BUMP SPRING TO BE FLAT UNDER FULL LOAD GROUND C OF REAR AXLE 17.000 DIA RIMS 7.500 TYRES 14.700 ROLLING RAD C OF FRONT WHEEL Stamp: ROLLS-ROYCE LTD. PRINT ROOM MAY 7 1935 DERBY LEC4449 Table of Dimensions: THESE DIMENSIONS ARE WITH A 3.000 FRONT BUMP (MAXIMUM) WHEEL & TYRE SIZES COLUMNS: RIMS 17.000 TYRES 7.500 | RIMS 17.000 TYRES 7.000 | RIMS 18.000 TYRES 7.500 | RIMS 18.000 TYRES 7.000 A: 6.250 | 6.050 | 6.325 | 6.125 B: 9.250 | 9.050 | 9.300 | 9.100 C: 21.050 | 20.850 | 21.050 | 20.850 D: 5.600 | 5.400 | 5.625 | 5.425 E: 8.750 | 8.550 | 8.800 | 8.600 F: 6.250 | 6.050 | 6.300 | 6.100 G: 9.500 | 9.300 | 9.500 | 9.300 H: 6.000 | 5.800 | 6.000 | 5.800 I: 9.500 | 9.300 | 9.500 | 9.300 J: 10.000 | 9.800 | 10.000 | 9.800 K: 6.300 | 6.100 | 6.375 | 6.175 L: 5.000 | 4.800 | 5.100 | 4.900 M: 9.000 | 8.800 | 9.200 | 9.000 N: 5.200 | 5.000 | 5.200 | 5.000 O: 9.250 | 9.050 | 9.250 | 9.050 P: 19.075 | 18.875 | 19.075 | 18.875 Q: 9.100 | 8.900 | 9.100 | 8.900 R: 4.700 | 4.500 | 4.650 | 4.450 S: 8.600 | 8.400 | 8.450 | 8.250 T: 4.000 | 3.800 | 3.875 | 3.675 ROLLING RADS: 14.700 | 14.500 | 15.200 | 15.000 SIDE DIA OF TYRE: 31.800 | 31.400 | 32.800 | 32.400 V: 6.350 | 6.350 | 5.850 | 5.850 W: 4.375 | 4.375 | 3.875 | 3.875 | ||