After learning to hover and fly in forward flight, for most RC helicopter pilots, a natural progression is to learn basic aerobatic maneuvers such as loops, rolls, stall turns and pirouettes. However, today’s RC heli pilots are looking for a lot more heart-pounding excitement and ultimate thrills, and this leads us into the 3D realm of helicopter aerobatics. So how do you get started and learn to do 3D maneuvers?
Fortunately there’s an answer to that question. Like building a house, you need a foundation from which to build on. In our case, a foundation of skills is needed with a complete understanding of setting up the helicopter, radio programming, and basic piloting skills for starters. This basic foundation creates a path that builds upon itself to achieve a high level of success. One thing you must possess is determination and a very strong drive to succeed, as the learning curve can be quite steep and long. If you have the desire, drive and motivation, you’ll be astonished to seethat what you first thought to be impossible, is now easily within your grasp.
In this article, we will introduce helicopter and the radio system basics. In another issue, we will discuss safety, flight simulators, the 3D setup and the prerequisite flying skills that will prepare you to venture into 3D maneuvers. Do you really need to read more than one article just to prep for the world of 3D? If you are serious about becoming a 3D pilot, the answer is yes.
Now, the material being presented here is by no means the only way to go about learning 3D aerobatics, as RC pilots have different ways of learning, preferred setups and flying techniques. One thing that will help you a lot is to join a heli club or seek out a local RC heli expert that has the skills you wish to develop. Having a mentor is an invaluable asset. One point that can’t be stressed enough is safety. The journey you’re about to embark on, can have many consequences if approached incorrectly. An out of control RC helicopter can be very dangerous. Extreme caution, safety and good judgment must be used at all times. One thing that is going to be assumed in this article is that you already know how to hover, fly around and can do some basic maneuvers and are ready for the next step. So grab your favorite beverage, get comfortable and hang on!
One of the most common questions asked is, which heli is best suited to learn with. Well that question has many answers to it. Most of today’s helicopters are very well suited for 3D aerobatics and some are designed for just that purpose. So you need to ask yourself some questions. What do other heli pilots in your area fly? Which size heli is best for me? Is there a hobby shop in the area and how available are parts? What brands do they stock and support? Will I quickly out grow the capabilities of the heli? And most importantly, what’s my budget? Recently, electric powered helicopters have taken the hobby by storm and have a lot to offer. They do however require a different skill set and are an entire article by themselves. So this time around, we’ll only concentrate on glow-powered helis.
Let’s break it down. If there is a heli club nearby, check out what other pilots are flying, as there’s already a built-in knowledge base. No sense of trying to reinvent the wheel! These heli pilots can also point out any pitfalls, weak points, upgrades and durability of the helicopter you’re interested in. As far as size goes, there are three basic sizes of glow-powered helis commonly in use today and each has advantages and disadvantages.
First is the .30-size and this is usually used by beginners just starting out in RC helicopters. They are great for learning to hover, as a rule suffer less damage when crashed, are less intimidating to fly, and are economical to own and maintain. On the down side, because of their lower power and performance, learning maneuvers will require a certain amount of finesse so you don’t overpower or stress the engine. The tail rotors are often not powerful enough for demanding maneuvers or backward flight.
If you start with a .30-size heli, chances are pretty good that once you start learning aerobatics, you’ll quickly outgrow it. Also, because of their smaller size, they are affected more by wind, can be more demanding to fly, and can be difficult to see at a distance. The .50-size heli has really come into its own the past couple of years and have a lot to offer. Since they are larger than the .30-size model, they are easier to see from a distance, have a good power-to-weight ratio, which translates into better performance. The operating costs are reasonable and maintenance requirements low. They are usually easy to build, and that means easy to repair. Also, tail rotor control at this level starts to be very good. Like the .30-size, wind can play a factor with its lighter weight, and replacing crash parts will cost you more. There really are not a lot of disadvantages to this class of helicopter.
The next size is the .60/.90-size heli and these big boys are king and offer the most performance and set the standards. As can be guessed, performance is stellar; they have outstanding power-to-weight ratios, offer excellent quality parts and materials, are designed from the onset to handle the demands and rigors of hard-core maneuvers, and have very good tail rotors. While the .60-size heli has been eclipsed by the .90-size in recent years, don’t overlook them, as they still offer value and performance when compared with a larger .90-size heli. The biggest downfall of both though is their cost. The cost of kits, engines, servos and blades is greater thus making it more difficult to get started in this class. Maintenance and repair costs will also be higher as quality parts and materials cost more.
Fuel consumption is also a factor to consider, you can easily go through a gallon of fuel in a day spent at the flying field. I know I have! Another consideration is replacement parts. Is there a hobby shop nearby that supports the brand and model that you’re flying? There’s nothing worse than waiting for special orders to arrive at your hobby shop or from an on-line vendor. In this case, sticking with what the crowd flies can be advantageous. Besides, having a brand that no one else flies can lead to many frustrations as help will be difficult to come by. So when considering the purchase of a heli, ask yourself these questions, think about what you want to accomplish with it and the answers will guide you in the right direction.Personally, I think a .50-size heli offers the best mix of economy, quality and performance thus allowing the aspiring 3D pilot to go all the way from basic maneuvers to full-blown 3D.
The radio system, servos and gyro you use will have an influence on your journey into 3D flight. The old saying that You get what you pay for is most appropriate when it comes to outfitting your heli. There really is no way of getting around using low-end equipment and the bigger the heli, the more demands it places on the servos and gyro. Not only is it important for performance, but also for safety. Having a servo or battery fail in flight is very scary and a dangerous occurrence. So let’s take a look the requirements.
First is the transmitter and there are many to chose from with many different features. Again, there are three basic categories, low, mid, and high-end, with price determining features and functions. Most pilots will find everything they need in a mid-range transmitter, and these radios are very good because they have the most needed features and are pretty easy to program.
Some of the basic features your radio should include are: four flight conditions (normal, idle up 1, idle up 2 and throttle hold) servo reversing, end point adjustment, sub trim, a minimum of a five-point throttle and pitch curves, program mixing abilities, swash type and cyclic collective pitch mixing (CCPM). Unless your budget can afford it, go with a mid-range radio. If you use an entry-level radio, you’ll find that you will quickly outgrow it.
The type of servos needed depend on the size of your heli (30/50/60/90) and the more advanced and demanding your flying, the better quality servo you will need. Stick with well known brands and with servos that are designed specifically for helicopters. Just like everything else, servo choices vary greatly and you have analog and digital to choose from. analog servos are the tried and true workhorses and are usually the most cost effective. But when compared to the latest generation of digital servos, they do tend to fall behind.
Digital servos offer better holding power, high accuracy and precision and incredible speed. They do however place a greater load on the battery and often cost more. One thing to keep in mind is that you want the collective and throttle servos to be close in speed. If they are significantly different, the throttle and collective responses will not match properly. The key factors to consider are torque and speed and here are some thoughts on servo requirements.
Cyclic servos should offer good speed, torque and high precision. The collective servo should have higher torque and precision, while the tail rotor servo needs high speed and precision. The throttle servo speed should match the collective servo, low torque is OK. If your heli uses a CCPM control system, all of the servos controlling the swashplate must be the same type or the control system will not function properly.
Vital for 3D flying is a high performance servo for the tail rotor and it should be designed for tail rotor operation.Some of the heading hold gyros offered today come with a matching servo or recommend what servo to use. Do not use a standard servo that offers just high speed as you’ll never realize the full potential of the gyro. The gyro is one piece of equipment that you do not want to skimp on and get the best you can afford. Head lock gyros are the standard today and they are a godsend for total tail rotor control in all situations.
When you have a properly setup gyro and matching servo, you can concentrate more on learning maneuvers instead of trying to keep the tail in line. Another question often asked is about the use of governors and are they really necessary? While they do add cost and complexity to the helicopter, they are not a must have item. Again like everything else, there are advantages and disadvantages to using them.
The main advantages are that it’s easy to obtain a constant main rotor rpm, you really do not need to setup a proper throttle curve and you don’t need to setup cyclic or tail rotor to throttle mixes. Disadvantages included the added cost, mounting magnets, governors usually lag a little behind the collective demand, and in-flight failure. If you do use a governor, I highly recommend that you have proper throttle and pitch curves setup in your radio. If the unit ever fails in flight, you’ll be able to safely land the heli.
I hope you have enjoyed my preliminary comments on helicopters and radio systems for the aerobatic pilot wishing to venture into 3D. Look to future issues for more information that will help the beginner 3D pilot achieve success.