There are a lot of factors that go into Propeller Theory and the effects of blade pitch.
However, generally... the smaller the pitch angle, the more torque is generated; and hence the better the climb performance – but (as there is always two sides to the coin) – as the blade pitch is
decreased, the cruise speed is negatively affected. The cruise speed needs a higher pitch (more air to grab) to maintain a good top speed; so as the blades AOA decreases (less pitch to get better climb), the cruise speed also tends to decrease.
To understand the effects of blade pitch... think of the analogy between a standard shift transmission in a car and the prop's pitch.
1st gear (the car's lowest tranmission gear, and relative to a Propeller blade - the smallest degree of pitch) gets the car "off the line", with a lot of torque, but this gear allows very little top-speed (like a small propeller blade pitch).
Now moving on through the transmission's gears, to the highest gear, you
find that these gears will provide far more top-speed, but little torque/power.
The same concept is basically true for Propellers. The smaller the pitch in the blades (6-8-degrees - like the lower the gear of a car) the better the torque/power performance; but the harder it is to obtain high speeds. The greater the pitch (14-16-degrees) the greater
the potential for top-speed in an application, but the harder it will be to get the craft moving (i.e., climb performance decreases)
.
