It is obvious that the amount of work we did depended on the force (lbs) we used and the distance we traveled (feet). Better yet, why don’t we just push hard enough to get the chair moving and then walk to the desired new location? You see, we could go find some heavy board or cabinet, tilt it so that it is lying against the chair, and now the chair is still experiencing the same pounds of force as if we were still pushing, yet we could go take a nap! But when the chair actually moves, then the board or cabinet falls off and if more motion is desired someone has to do the work of repositioning the force-producing object. Although I agree that our muscles would get tired if we kept this pose for a lengthy period of time, technically work is not done until the chair moves. It seems to most of us that work would be done when the force is applied, when we bent our arms and gave the chair a good shove. Let’s say that we want to push a heavy chair from one side of a room to the other. Work is done, energy is expended, when a force moves through a distance. The dictionary defines torque as “A force that produces a twisting or rotational effect.” And what is a force? Merely a push or a pull, measured in pounds (lbs) in the typical American system of measurement. Bear with me here as I make sure you understand the exact definition of power.

I will begin by reviewing the basic formula for the power that is being delivered to the propeller shaft.

Please read on to gain a deeper understanding of why we choose the propeller speed that we do. Other pilots consider this a matter of technique and vary the RPM based on conditions. They merely follow the manufacturer’s checklist procedures.

For many King Air pilots this is neither confusing nor controversial in any way. In my opinion, it is not important at all and I cannot understand why the instructor would have taught that it is! The intent of this article is to discuss the pros and cons of our selection of propeller speed in climb and cruise. He mentioned that when he received his Initial training in this plane a few years ago the instructor emphasized, often and forcefully, that the propeller speed must be reduced back to 1,500 RPM (from the takeoff speed of 1,700 RPM) at 400 feet AGL on every departure.

This week I flew with an owner-pilot of a beautiful, late-model King Air 300, doing a bit of in-aircraft recurrent training.

Bet prop speed