5. ENGINES – OSCILLATING
Q. How is the reversing/speed control set?
A. It depends on the situation. The valve can be operated in any position giving an increase or decrease of rotation direction or speed. We suggest you run the steam plant up and experiment with it. While you may be tempted to move it with your fingers during testing we suggest you attach a stiff wire to enable you move it as it can get quite hot.
Q. How is the reversing/speed control set - another answer!
A. “The Clyde and Avon steam engines have a speed and direction control valve on the top of the centre trunk. This control can work in two positions, 180 degrees apart, for both speed and direction control. The centre position of the valve within each 180-degree segment has the centreline between the two actuating lugs at 90 degrees to the centreline of the engine, on either side. About 90 degrees of this is “dead space” on the controller valve. Thus, the controller has about 90 degrees to control the movement from full ahead, through the forward/reverse transition, to full astern, in either of the two basic 180-degree segments. There is approximately 45 degrees of movement available for speed control for forward and reverse switching. The speed control is a fine control so once you have established the full throttle position in any direction, only a fine adjustment of the controller is required to achieve speed variations.”
Q. Does the Clyde need an extra flywheel?
A. No - it now has 3 flywheels – small but highly effective. We have found that if you add an extra flywheel it can interfere with the engine response to the forward and reverse i.e. there is too much inertia in the system
Q. Why does the Tyne not have reversing?
A. The Tyne is a single cylinder engine and the direction of rotation of a single cylinder engine can only be changed at installation time by manually reversing the steam input and exhaust line connections on the engine trunk. Also, single cylinder engines are not consistently self-starting, they may need a finger flick to a flywheel to start them.
Q. During start-up, why does the engine "blubber", emitting water and steam from the working surfaces of the engine trunk?
A. This is normal for this type of engine. The engines are designed to clear condensate in this way.
Q. Engine stalls or emits water without much movement during start-up.
A. Boiler overfilled.