Front Strut A tube bracing the nose of the trike to the top of the mast. Takes a small percentage of air loads and stops the mast from bending on landing. Required by law in Australia. Measures the operating speed of the engine. Not generally necessary.
Magnetic Compasses are also subject to errors of lag and overshoot during turns.
Measures the temperature of the cyliner heads and is a good guide to the state of lubrication of the engine. Relatively slow response. Provides quick feedback on the health of the combustion process. Very Highly Recommended Hour Meter keeps track of the number of hours an engine has had in service. Mandatory in some aircraft by law.