Hi friends,
Today while testing my new built (will post pictures and videos soon), What i found that :
1:When the plane is at Rest, engine running, propellor moves at extremely high RPM.
2: when the plane is at motion, or in air, the RPM of propellor decreases at same throttle as in above condition.

This experience is audible,and i have not used any equipments. Means, i made it out by hearing the frequency of engine knockings..

I wonder why does it happen?., or does it really happen?.. Or its due to "doppler's effect".

For what i've learned from Augustinev's posts, the RPM should increase as the prop unloads when the plane starts moving through air.

(a) Blade Element are the airfoil sections joined side by side to form the blade airfoil. These elements are placed at different angles in rotation of the plane of rotation.

(b) The reason for placing the blade element sections at different angles is because the various sections of the blade travel at different speeds because of thier different distance from the hub (Hub Centre being at zero speed.Imagine If all the elements along a blade is at the same blade angle, the relative wind will not strike the elements at the same angle of attack.

(c) that is why, prop blade has a small twist (due to different angle in each section) in it for a very important reason. When the propeller is spinning round, each section of the blade travel at different speed, The twist in the propeller blade means that each section advance forward at the same rate so stopping the propeller from bending. (these advances vary because of the presence of the aircraft behind the propeller. Therefore they are GMP, EMP and PP (Geometric Mean Pitch, Experimental mean Pitch, and Practical Pitch, more about this later)

(d) Thrust is produced by the propeller attached to the engine driveshaft. While the propeller is rotating in flight, each section of the blade has a motion that combines the forward motion of the aircraft with circular movement of the propeller. The slower the speed, the steeper the angle of attack (See image) therefore stands to reason max thrust of the propeller is when it i snot in any forward motion (That particular angle of attack may not be the optimum), in fact a prop has only one optimum forward speed below and above which the drag is more, that is the reason why real life aircraft has a CSU (Constant speed unit)

(e) to answer the question of RPM, at max angle of attack, full throttle, RPM will be lowest, as the speed increases (see image) the rpm will increase and it will become maximum at the propeller zero lift angle of attack (Possible only in dive, for obvious reasons), this fallacy could be our man doppler