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).
Comparison of the 20HP gearbox with a freewheel in the sideshaft against the De Lavaud scheme.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan213 | |
| Date | 11th October 1929 | |
| HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} ORIGINAL DA{Bernard Day - Chassis Design}1/M11.10.29. X5770 X4474 X5310 20HP. GEARBOX. FREEWHEEL IN SIDESHAFT. It will have been observed that this arrangement does not function exactly the same as the De Lavaud and other freewheels mounted behind the gearbox. In the sideshaft arrangement the third motion shaft cannot be stopped. In the De Lavaud scheme all the shafts can be stopped, and all will stop if time for it is allowed. The effect of this feature in the sideshaft scheme is to require the second motion shaft to be speeded up in changing down. As this shaft tends to stop when the clutch is withdrawn, to wait is a disadvantage, and the change should be made as quickly as possible. With the De Lavaud scheme the third motion shaft must be slowed down for changing down, and this is its natural tendency. Thus waiting slightly is an advantage. Furthermore, since all shafts slow down on declutching, any clashing of gears due to inertia of any of the parts tends to be slight. In the case of changing up the 20HP. scheme has a slight advantage in that the sideshaft does tend in the right direction, viz: to slow down, but if too long a wait is made it will slow too much, and must be speeded up by the third motion shaft. With the De Lavaud scheme there is no danger of waiting too long because all shafts are slowing. It would seem, in fact, as though in the 20HP. scheme the inertia of the second motion shaft might be very important. DA.{Bernard Day - Chassis Design} | ||