| Description | The file contains correspondence and enclosures, file notes, drawings and sketches and information on equipment related to a variety of topics, but it is mainly concerned with power flying for the Lower Theatre (drive equipment, rope brake, hydraulic equipment, electric motors, switches, hoists, head sheaves, head joists, thermistors), including information provided about potential solutions by different manufacturers and the tendering process. Also included is information about friction drum hoisting; scenery hoists and scenery hoist control systems, Upper and Lower Theatre stage wagon systems, point hoists, auto patch panel, counterweights, gallery handrails, head steels and spotline hoists. Correspondents include Theatre Projects Consultants Ltd, Evershed Power Optics Ltd, Mole-Richardson (Stage & Studio Engineering) Ltd, Flint & Neill Ltd, Tele-Stage Associates Ltd, Hall Stage Equipment Ltd, Denys Lasdun & Partners and Sir Robert McAlpine & Sons Ltd. There are a large number of drawings in this file: sketch number 904/SK/481 showing a powered interlocked rope brake, Drawing number Y 25618 'Control Panel - Control Section Lower Theatre' (Fig 6b), drawing Y 25617 'Cyclo Allocation Indicators & Setting Keyboard System Control Panel - Lower Theatre' (Fig. 6a), drawing number Y 25616 'Wagon Selection Panel - At End of Trunking Lower Theatre' (Fig 5), drawing Y 25615 'Control Panel & Layout of Sections Lower Theatre' (Fig. 4), drawing Y 25614 'Switch Module - Lower Theatre' (Fig. 3), drawing Y 25613 'Schematic - Switch System Lower Theatre' (Fig. 2), drawing Y 25612 'Block Diagram Lower Theatre' (Fig. 1), sketch number E3905/Sk1 'National Theatre (Lower Theatre) Power Flying Gear, sketch number 1 'National (Lower) Theatre Power Flying', rough sketches of control panels and circuitry, sketch number SPOT/3 'Lower Theatre 6 Off Spotline Hoists', sketch SPOT/2 'Upper Theatre 20 Off Spotline Hoists' and sketch SPOT/1 'National Theatre Spotline Hoists - Scheme', sketch number L0901/SK1 'National (Lower) Theatre Power Flying System - Head Pulley Loadings', sketch L0901/Sk2 'National (Lower) Theatre Power Flying System - Static Loading Condition', sketches L0901/SK3 and L0901/SK4 both titled 'National (Lower) Theatre Power Flying Hoist Loading Conditions, L0901/Sk5 'National (Lower) Theatre - Power Flying Head Sheave and Proposed Mounting Detail' and sketch E3905 'Hoist "A" for 400 kg [named] Powered Set Load + 100kg Exchange' accompanied by 4 pages of notes, sketch number L0901/PF/SK10 'National (Lower) Theatre Traction Unit for Power Flying System', an unnumbered sketch 'National Theatre - Power Flying Revised Relationship Head Sheave/Head Joist', sketch number L0901/SK 'National (Lower) Theatre - Power Flying Proposed Modification to Head Pulley Mounting', 3 sketches 'National Theatre (Lower) Additional Gallery for Power Flying'. Original card folder disposed of. '1 Power Flying Mar 72-Oct 73' was written on the front, and '904/5B5 National Theatre Powered Flying Equipment Closed October 1973' was written on the spine. |