Originally Posted by
torquey401
In simple terms, beta range occurs anytime the constant speed unit of the prop governor does not control prop blade angle.
The above is the most succinct, most accurate, and most truthful answer I have seen in the whole thread.
All I can add to it is this - If your aircraft is equipped with a reversing propeller, you can determine whether it is in beta range as follows:
1) If the propeller speed that you have set with the propeller speed levers equals the rotational speed of the propeller that you observe on the Np gauge, you are NOT in beta range (you are in constant speed range).
2) If the propeller speed that you have set with the propeller speed levers is LESS than the speed you see on the Np gauge, then you ARE in beta range (beta reverse valve is controlling the propeller).
Don't let anyone else confuse you with more elaborate explanations, or baffle you with BS - the quote cited above and the two points I have added are the simplest possible way of defining it.