Dynamometer test on a Spectre rear axle, comparing performance figures with Bentley and Phantom II models.
| Identifier | ExFiles\Box 92\5\ scan0035 | |
| Date | 31th October 1935 | |
| To E. {Mr Elliott - Chief Engineer} From Hs {Lord Ernest Hives - Chair} /Gry. {Shadwell Grylls} c.c. to Wor. {Arthur Wormald - General Works Manager} c.c. to Da. {Bernard Day - Chassis Design} c.c. to By. {R.W. Bailey - Chief Engineer} c.c. to Hdy. {William Hardy} √302 Spectre(Codename for Phantom III) Rear Axle. We have recently carried out a dynamometer test on a Spectre(Codename for Phantom III) rear axle fitted to the Vulture(Experimental 6 CYL OHV LONG STROKE / Aero Engine) car. This axle had previously run 2,500 miles on the road. A J-111 gearbox was used of ratios .765, .49 and .355. On 1st gear the load on the brake was 800 lbs. whereas the most recent Ph.II pulled only 615 lbs. (The conversion factor for brake load to thrust at road wheels is 3.750). As the Spectre(Codename for Phantom III) is lighter than the Ph.II such a low gear is not required. 1st gear figures for the Bentley and Ph.II are - | | Thrust at Road Wheels (F) | Weight (W) | | F {Mr Friese} /W | | |---|---|:---:|:---:|:---:|:---:| | | | Unladen | Fully Laden | | | | Bentley | 1420 | 3600 | 4400 | .395 | .325 | | Ph.II | 2300 | 5700 | 6500 | .405 | .355 | | Spectre(Codename for Phantom III) calculated from Vulture(Experimental 6 CYL OHV LONG STROKE / Aero Engine) figures; .833 of torque and .37 1st. gear | 2400 | 5500 | 6300 | .437 | .382 | | ||
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).