In the first article of this series, I showed you how to add RC controls to a common toy store chuck glider, the Air Hogs Titan. It may not be pretty, but it has elements that most budding RC pilots truly need: simplicity and affordability. This time around, I'll illustrate a few techniques for using the Titan to learn how to fly. You'll probably get some exercise while you're at it!
No matter what model you are using as your primary trainer, the learning curve is always eased when you have an experienced pilot who can show you the basics. Most RC clubs have a process ironed out for training new pilots. The Titan probably doesn't fit that traditional training template. However, it would still benefit you to enlist the aid of a seasoned pilot to get you over the initial hurdles. If you don't have access to a pilot, any eager helper with a decent throwing arm and tireless legs is a useful alternative. Kids seem to enjoy it and there are plenty of opportunities for hand-on physics lessons.
As you go through the process of learning how to fly, you will make a lot of mistakes…that's okay. The airplane will be flying slowly and close to the ground most of the time. So you're not dealing with much energy. Additionally, the Titan has several ways of dissipating energy when it hits the ground. It isn't likely that you will break anything.
In most minor crashes, the wings will pop loose from the fuselage. Just put them back in. A harder impact may cause the battery to rip free of the Velcro. Again, just put it back in place and keep on flying. If you do manage to break the Titan, repairs can be made with white glue or even tape. So go forth with no worries about breaking the airplane. It's no big deal.
Since we've already balanced the Titan and ensured that the taileron control surfaces move in the correct directions, the next step is to get the model trimmed. We want the airplane to fly in a predictable manner without any control inputs. This means that a gentle toss of the model should result in a straight ahead and gradual descent to the ground.
Wait for a calm day and find an open area such as a soccer field or baseball diamond. You'll want to give yourself plenty of room and make sure that no innocent bystanders are around. Turn on the radio gear. Give the model a gentle forward toss with the wings level and the nose pointed at the horizon. You should get a smooth glide to a landing spot 30-40 feet away.
If, for example, the model noses in after launch, you need to adjust both tailerons so that they are more elevated when the controls are neutral. This can be accomplished by tweaking the trims on your transmitter. Whatever direction the model is deviating from the desired glide path, you want to input trim in the opposite direction. To correct nosing in, you want to input "up" trim…which actually means you'll be moving the trim lever downward. Likewise, if the Titan consistently turns to the right, input left trim.
Older radios have an analog slider for trim while newer models have buttons that you push repeatedly for more trim. Small amounts of trim can have a big effect, so make incremental changes between each test glide. If you find that you have to make large trim adjustments, you may find it easier to change the length of the relevant pushrod(s) by threading a clevis in or out.
Taking the Wheel
Once you are satisfied that the Titan is properly trimmed, it's time to start making control inputs to purposefully alter its flight path. Continue with the same gentle, level toss (always directly into the wind) and begin making inputs in each direction to observe the effect. Each of these flights will only be a few seconds long, but your learning will be fast paced.
The best thing to focus in during these initial flights is the landing flare. Basically, your goal is to gradually pull back on the stick to raise the model's nose just before it hits the ground. When you do it correctly, the Titan will touch down softly and slide to a stop. If you flare too soon or too harshly, the model will stall, resulting in an uncontrolled (but harmless) fall to the ground. Practice flaring until becomes second nature.
After mastering the flare, you'll be itching for more flight time with each launch. You can begin to throw the model with more force, but technique is still very important. Keep the wings level and the nose toward the horizon no matter how hard you throw it. The additional speed from a harder throw will make the model climb after you release it. If you throw with the nose pointed toward the sky, you will probably just cause the airplane to stall.
The park in my neighborhood has a field with a gentle hill. I stand at the peak of the hill and launch the model into the wind. The extra flight time afforded by the Titan flying downhill will let you explore a wider range of control inputs and observe their effects. You will soon see that a soft touch on the controls results in a smoother flight path and longer hang times.
If you have someone who can launch the Titan for you, it is a good idea to change up your position relative to the glider. You goal is to be comfortable making control inputs no matter what orientation the airplane is in. For instance, when the glider is flying toward you, its right and left are no longer the same as yours. It takes some time to get used to the varying perspectives, but you'll get the hang of it with practice.
Flying Ever Higher
As you build your skills, you will want to launch the Titan to higher altitudes. There are several established methods for doing this with conventional RC gliders. You can tow them behind a powered model, zing them up with a large bungee cord set-up called a "hi-start", or use a tow line attached to an electric winch. While none of those methods are very practical for the Titan, we have alternatives.
The simplest method I know of is to have someone run while pulling the glider with a length of small-diameter rope. The length of the tow line will depend on how high you want the glider to go. If you do things correctly, more rope equals more altitude. Start with 50 feet of line and work your way up.
I've been using mason's twine for a tow rope. It is small, relatively light, and easy to work with. I buy the fluorescent colors so that the line is easier to see both in the air and on the ground. The only drawback to mason's twine is that it may absorb dew or other moisture on the ground, making it heavy. Monofilament fishing line can also be used. I've utilized 20 pound line with good results.
In order to tow the Titan, you need a hook on the bottom of the fuselage. This hook engages with a metal ring on the end of the tow line (I use a split ring from an old key chain). I made a hook by modifying a picture hanging bracket and gluing it to a small piece of sheet plastic with GOOP adhesive. I then taped this rig to the bottom of the model using strapping tape. Double check the model's balance after adding the tow hook and reposition the battery as necessary.
The location of the hook will determine how the model performs while being towed. With the hook close to the nose, the Titan will be very directionally stable, but it is not likely to climb. As you move the hook rearward, you can trade stability for climb. After some experimenting, I've placed the tow rig such that the apex of the hook is 3.5" forward of the model's center of gravity.
My glider towing gear includes a clothesline pulley on a handle, mason's twine and a tent stake.
Rather than pulling the Titan off of the ground, I've found that launches are cleaner when the pilot holds the model off of the ground as the runner begins their sprint. Ideally, the glider will climb in an arcing path. As the Titan nears its apogee, the ring should fall free of the hook. Now you're gliding with more altitude than a hand launch could achieve.
Whereas most of your flights up to this point were probably not long enough for any significant changes in direction, the extra altitude of a towed launch may permit you to turn around and bring the Titan back to you. That will save you and your launch buddy some walking…a pretty good incentive in my book. This is where the time that you invested in flying from multiple perspectives will pay off big time.
Hooray for Science
My son volunteered to be the beast of burden for my tow rope testing with the Titan. The field we were using is quite rough, and not conducive to running at top speed. We were able to get a few good launches when there was a decent headwind, but there were other times when the Titan just wallowed on the end of the line, looking for more speed. I was prepared for this scenario, so I made a quick adjustment.
I had brought along a small pulley. This particular unit is a plastic clothesline pulley that I bought for a few dollars from Home Depot. I made a handle for it using a scrap broomstick and a short piece of music wire.
I unspooled about 150 feet of tow line, routed it through the pulley and secured the base end of the line to the ground using a plastic tent stake. My son was positioned just in front of the stake with the pulley in hand. The Titan and I were located behind the stake at the opposite end of the outstretched tow line. When my son began running forward with the pulley, the Titan now travelled forward at twice his footspeed. That was the kick in the pants we needed for better launches at this field.
Since the tow line effectively becomes shorter as the launcher runs forward with the pulley, there will come a point where they actually begin to pull the model back down rather than upward. This point will vary depending on the length of the tow line. The runner can't see what's happening above them, so they will rely on shouted orders from you to stop running…at least the first few times. The tow line will fall off of the hook when the runner begins slowing down.
The Titan is not all that efficient as RC gliders go. With a good launch you might get flights lasting 45 seconds to a minute--maybe more. That may not sound like much, but it's plenty for learning new skills. Pick one thing to work on for each flight. Repeat it until you get that particular skill nailed down, then pick a new challenge to conquer.
I personally enjoy the thrill of towed launches…even with a simple glider like the Titan. It represents a coordinated effort between two people to attain a successful flight. There are a lot of variables involved. A great launch followed by a long smooth glide is something to celebrate.
In the final installment of this series, I'll illustrate one way to add a propulsion system to the Titan. Not only does this significantly broaden your limits on flight time and performance, but it also adds a new control element to manage (throttle). It's the next logical step in your low-buck RC flight training journey.
Terry is a freelance writer living in Lubbock, Texas. Visit his website at TerryDunn.org and follow him on Twitter and Facebook. You can also hear Terry talk about RC hobbies as one of the hosts of the RC Roundtable podcast.