Almost all rubber hoses have a shelf life. Most are around eight years. The symptoms were fluctuating manifold pressure readings, and the hose completely crumbled when grabbed.
In Case You Missed It
Wind Tunnel
The author discusses the theory and effect of constant-speed propellers on piston-engine airplane performance, and compares fixed-pitch versus constant-speed props, effect on thrust HP and propulsion, the comprises involved in choosing a prop, how props perform in various conditions and phases of flight, how variable-pitch props work, and why a constant-speed prop is the best choice for high-performance aircraft.