When you first go out to fly with a new park flyer, often it’s hit or miss as to what the weather is going to be like and whether or not the area winds will be favorable. Of all the variables we take into account each time we release our lightly loaded model, the wind is what we have the least control over. If you’re in a sailboat, or are flying a kite, strong winds are good. For RC pilots, not so much! By following a few guidelines and understanding our surroundings better, we can get the most out of what Mother Nature dishes out for us. Often, whether we have a good or bad day at the flying field all depends on the winds.
As a little reminder, wind is the byproduct of how solar energy affects the weather. In simple terms, hot air rises and cooler air sinks. The motion of the rising and falling air currents produces the winds we feel and see the affects of. Like the weatherman on TV tells us, high and low air-pressure zones drive the direction of the winds. But let’s get back on track.
Calm, blustery and windy are all relative terms. For the beginner pilot, the calmer the conditions, the better. However, before you head out to your favorite flying area, an easy way to read wind is to look at the tops of tall trees. Are the branches and leaves whipping about, or are they calm and motionless? How about flags atop big flagpoles? Is Old Glory pointing at the ground or is it proudly flapping in the breeze? You get the idea-calm skies mean fun, while big wind means stay indoors and fly on your simulator. You’ll also notice that the time of day also has an affect on the wind. Due to solar energy, the early hours right after sunrise and before sunset are the calmest times of the day and most modelers tend to take advantage of the calm. Generally, cloudy days (low air pressure zones) are calmer than sunny, high-pressure days.
During flight, the relative direction of the wind and your direction of flight is also very important. Always take off or hand launch your model directly into the wind. Flying upwind gives your model increased airspeed and airflow over its wings with a relative low over the ground speed. This is important when you are working for altitude. Whenever possible, try to land directly into the wind. Taking off or landing in the same direction as the wind is blowing (downwind), increases your ground speed and the distance your model needs to land safely. Flying at an angle to the relative air flow is called “flying crosswind.” There’s nothing wrong with doing this, but it does require more skill to fly properly. Similar to trying to cross a flowing river with a boat, you have to compensate for the airflow direction to get to where you want to go.
Turbulence in airflow is also something to be aware of. If you don’t pay particular attention to your model’s flight path, you can be surprised when a model gets buffeted about when turbulence pops up. Rough air can lead to you losing control or having your model stall and lose lift as the direction and force of the wind quickly changes. Turbulence is caused when wind flows and swirls around obstacles such as trees, fences or buildings. The shape and location of your flying area can also contribute to air turbulence. Trees in particular can, and often do, affect the way a model performs. Flying below the tops of trees or very high over them will keep you in calmer air. Turbulence is most felt at or around the tops of trees or in the breaks in a line of trees where the air flows through the open areas. Just being aware of all this dynamic air and obstacle interaction will greatly improve your ability to keep your model flying smoothly.
GETTING A RISE
Thermals are rising columns of air that are caused when the sun heats the ground. Darker patches of earth such as plowed fields and paved parking lots, heat up more quickly than lighter-colored areas that tend to reflect the heat instead of absorbing it. If you fly through a thermal, you might notice a wingtip suddenly being lifted, which causes your model to turn or roll abruptly. Thermals aren’t all bad, however. If you learn to find and then fly your model tightly within the rising air column, you can greatly increase your flight times and save power while doing it. Glider pilots do this all the time and stay up for very long periods. Like a surfer catching a wave, catching thermals takes practice-but it’s always a lot of fun.
Another form of uplifting air current develops when wind is deflected by a steep hill or cliff face. This upwelling airflow is known as ridge-lift and glider guys especially take full advantage of this wind condition when they go “slope soaring.” The size of the hill is not as important as having sustained winds. Both gliders and powered planes can benefit from this free, additional lift.
EQUIPPED FOR THE JOB
As with anything else, you have to have the right tools to get the job done. Lightweight, lightly loaded airplanes with only rudder and elevator control require calmer conditions to fly properly. If you want to fly regularly in less than perfectly calm conditions, consider a more powerful airplane that’s equipped with ailerons. Higher wing-loadings give models a more solid feel when you fly because the wind has less effect on them. The addition of roll control also gives aileron-equipped planes the edge when correcting for windy conditions more quickly. More experienced pilots can even cross control the rudder and ailerons so they can side-slip their plane during landings. This allows the model to be flown in for landing with a much steeper approach angle without the airspeed becoming too great. This is a particularly good task to learn if you like flying scale Piper Cubs; when done correctly, this move is sure to impress everyone at the flying field.
So, there you have it. Don’t be grounded or limited in your RC flying just because the wind starts to blow. A little understanding about the situation you’re flying in and applying the correct adjustments will make you a better pilot and greatly increase your backyard flying fun! ?
Illustrations by Richard Thompson