High-altitude piston aircraft rely on massive amounts of compressed turbocharger air to keep things purring in the flight levels. This capability in thin air raises the risk of turbocharger shaft-overspeed and turbo failure. It also means that the turbocharger is capable of massive over-boost at lower altitudes. Because of this, we need a boost control system that is sensitive, quick, and accurate. The most effective way to do this, so far, has been found with hydraulically-operated controllers and wastegates. Note, some simple systems such as in the turbo Arrow or Seneca, the pilot performs as the turbo controller. In other words, the system is so simple a turbo controller has been left off and the pilot must take conditions and limitations per the POH into consideration to avoid over-boosting the engine or engines.
展开▼
