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).
Modifications and issues with the Stewart Tank, clutch, generator, and intake bend on a test vehicle.
| Identifier | ExFiles\Box 72\2\ scan0065 | |
| Date | 8th January 1926 | |
| Oy5-E-1826 -3- January 8, 1926. Stewart Tank. You should now have received the actual Stewart Tank we have been using on 12-MC. I gather that you have no objection to our using the Stewart, since, whether by intake restriction or otherwise, it does give us the results required. In the experimental report recently sent from your department your assistant refers to the slower dumping period of the Stewart. While this may be so, the point we want to bring out is the improved toggling action and the much quicker movement of the air valve giving a quick and definite tripping action, whereas the Autovac on 12-MC hesitated on dead centre in its toggling action during which time both air and vacuum valves were held open. Clutch. We have run 12-MC about 2000 miles with only 6 springs in the clutch instead of 8, and have not had any slippage. The action of the clutch is much smoother. Don't you think the trouble with the harsh operation of the Phantom clutch is that it is about 30% too strong for its job? Thanks for your note re clutch shuddering. We will set this up as soon as we have put in the 8 softer springs that we have on order. Generator. The most serious feature of the Phantom, to judge by 12-MC, is that the voltage rises too high to use the standard American "12-16 volt" bulbs without continual burning out. Therefore we have had to fit it with special "16-22" bulbs, which do not burn out, but give no light. You will have seen my letter Oy4-E-121125 on this subject. If the 3rd brush were adjustable we could set down the voltage very readily. As it is we shall probably have to take out the armature and grind it down to increase the air gap. Intake bend. I enclose print A-7683 showing scheme for an inserted tube intake bend, which we think will heat up quicker and be removable for cleaning. We think this might allow us to run without the choke valve, but have not yet got it on the car. Yours very truly, Maurice Olly New Year greetings MO/E | ||