Steam Engine Reviews/Arrowhead Bump Valve Summary

Steam Engine Reviews

The so-called Arrowhead Bump Valve engine design has been reviewed by several people at the current time (7/20/11). This page summarizes the design problems and provides suggestions on how to deal with them.

=Problem Summary=


 * Horizontal layout promotes wear, jamming, etc.
 * Water can condensing in the engine leading to a blow-out.
 * Placement of exhaust vent means compressing air in the cylinder and losing work.
 * Steam is admitted before top dead center, losing some work.
 * Valves must seat and create a seal against steam.
 * Valves are heavy and slow to react.
 * Valves take a beating from bump pins.
 * Valve opening and timing is critical - difficult to adjust.
 * Cylinder liner is expensive.
 * Cylinder end needs holes to let in (and out) air.
 * Piston rings are expensive.
 * Oiler is expensive.
 * Piston head is heavy, moving it loses work.
 * Piston head has no heat shield.
 * Bump pins may vibrate out of their holes.
 * Oil mixes with steam and causes pollution.
 * Crankshaft is built up of parts that must be precisely aligned or vibration results.
 * Engine is hot - no shields for safety.
 * Crankshaft is open - safety hazard.

=CAD Problems=