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The Power/Airspeed/Altitude Triangle
At any given time, a flying helicopter has a certain amount of available power, airspeed, and altitude. Thinking of these sources of potential energy can help you to visual the relationship between these forces and how energy can be converted into other forms while flying.
For example. Imagine level forward flight, utilizing all available power to achieve the highest possible airspeed in your helicopter. In this case, airspeed could be traded off for more available power. It could also be traded off for a gain in altitude.
Of course, other possibilities include trading altitude for airspeed, available power, or both. Or trading available power off for increased altitude or airspeed.
I offer this concept not to provide a lesson in aircraft energy management, but to help illustrate the relationship between the forces at play when working on flight dynamics. This is where the concept of harmony will come into play.
For example, let's say that you want your helicopter to have a high amount of lifting capability for its heavy weight (let's figure its a BIG helicopter). So you modify the flight dynamics and rotor configuration in order to produce a large amount of vertical thrust when the collective is raised. If you take this capability too far, it will begin to create negative side effects in other areas. In this case, all of that extra capability in lifting is going to show up negatively when you begin testing your airspeeds. You might find that for any given torque setting, your helicopter is producing far too high of an airspeed, or that you are forced to keep the nose of your helicopter at too low of an angle in forward flight. All because we wanted a little more lifting capability.
That is because these types of flight dynamics are interconnected, much like the concept in the power/airspeed/altitude triangle. It will be rare that you can make a significant adjustment to flight dynamics that affects one area of the triangle without it having some type of effect on another area of the triangle. There are ways to bring the desired dynamics into balance, and of course there are exceptions to the rule, but it is a good concept to keep in mind as you learn more about helicopter flight dynamics in flight simulator.
It might just make you a better pilot...to boot.
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