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).
Construction and mounting details for bodies with demountable cantrails, including Sedanca, Cabriolet, and Drop Head Coupé models.
| Identifier | ExFiles\Box 117\1\ scan0080 | |
| Date | 1st September 1936 guessed | |
| -10- BODIES WITH DEMOUNTABLE CANTRAILS. SEDANCA, CABRIOLET AND DROP HEAD COUPE. BODY CONSTRUCTION AND MOUNTING. The construction and mounting of the Closed Body has been dealt with earlier in this book. Bodies with a demountable top, in particular the Sedanca, the Cabriolet and the Drop Head Coupé, call for a special treatment, in view of the fact that they do not constitute a framed, box-like structure, and have a much reduced torsional rigidity compared with the fixed-head body. The Sedanca and the like bodies consist essentially of two rigid units, the scuttle and screen section in front, and the rear compartment and luggage boot at the rear. When the de Ville Extension is open, these two sections are united only by the body bottom-sides. It is essential therefore that the bottom-sides have the maximum rigidity, especially with respect to vertical bending. This may be achieved by the use of a deep vertical edge plate running continuously from the face of the scuttle to the rear wheel arch, constructed of plywood to which has been screwed a sheet steel edge plate, or of Plymax. There is no need to cut a door in this edge plate to give access to the petrol filter on the off-side as in the case of this class of coachwork the filter will be accommodated elsewhere on the chassis. The screen pillar, above the waist-rail, is a cantilever, which has to take the thrust of the de Ville extension arm when closed. The pillar should therefore, be reinforced, if made of wood, by completely panelling in sheet steel, prior to panelling with sheet aluminium, and this steel panelling should extend in the form of a gusset down to the bottom side as shown in Fig. 'b', sheet 4, and Fig. 'a', sheet 6. This gusset prevents the fore and aft movement of the pillar, whilst the Dural tubular struts shown also in Fig. 'b', sheet 4, prevent any transverse movement. A further reinforcement of the body structure can be achieved if the front door is made to act as a diagonal bracing between the scuttle at the screen pillar and the rearmost portion of the body at the centre pillar. This calls for strong hinges attached by bolts to the centre pillar, and for some form of lock other than the orthodox bolt lock. The lock must hold the door shut - face to the pillar in all directions and may take the form of a Silent Travel type lock, at the waist rail, or a double lock at the waist rail and the base of the pillar. In the case of the Sedanca and other bodies with a de Ville extension, it has been found expedient to cause the demountable cantrails, whether they be folding or sliding, to act as a tie between the top of the screen pillar and the top of the centre pillar. When the head is closed the cantrail must be fixed by some form of rigid attachment at both of its ends. The mounting of this type of body calls for a special treatment. Whereas in the case of the totally enclosed body the attachment of the scuttle to the dashboard and the frame is made semi-flexible, it has been found that in the case of bodies with demountable tops it is beneficial to make this attachment solid. No attendant disadvantages will result. | ||