Part 1: Soaring for Beginners | Contents | Chapter 2: Getting Started
This chapter introduces the concept of radio controlled soaring.
R/C soaring is poorly understood outside of the soaring community.
This overview should help to clarify what soaring is as a sport and why we do it.
Sailplane flying is the ultimate challenge. It is a pure sport, involving just
the pilot and the elements. You will be flying
your plane at the extremes of visibility, a mile away, at thousands of feet,
and in conditions that will later send a chill up your spine. You'll fly in
thermals so strong they take your plane out of sight in minutes. You'll have
flights where your knees will be shaking twenty minutes after you find out
the plane is still OK. You will fly
slopes in winds so strong you need ski goggles just to see the
airplane. There is little room for error. Unlike our powered
brethren, there is no throttle stick to kick in and go around. There's
only you and the elements.
At the same time soaring can be the ultimate in relaxation. I've had lazy
summer days where the plane just wouldn't come down. I've spent
afternoons lying in the grass watching the plane circle itself in
a big thermal, with my transmitter laying beside me on the ground.
There's nothing like hooking your first big thermal, hitting a perfect
landing, completing your first cross country flight or flying your
newest plane for the first time. Silent flight is good therapy for the
The people you meet while flying are equally entertaining. You can't
imagine how many good people there are in the soaring community.
From the local club to the yearly nationals, R/C soaring people are
all first rate. At many flying sites the best source of thermals is the
hot air rising from the pilots talking. Soaring pilots are a never ending
source of tall tales, any of which they will share with the slightest
provocation. One of the greatest challenges you will face is to get
some flying in between all of the kibitzing.
Flying a radio control plane is not as easy as it looks. For example,
a plane coming towards you has its rudder reversed. If you push the
stick left, it will turn to your right. It takes some practice to
consistently put yourself in the plane's frame of reference,
especially when the plane is in a bizarre attitude a long way from you.
It will take five
or six sessions with an experienced pilot before you can solo. Do not
try learning on your own. You will certainly crash the plane on
the first flight, and likely destroy your plane after a few flights if you
do. If you have an instructor to fly the launches and landings, the
life expectancy of your airplane rises dramatically.
Always have an experienced pilot teach you to fly. Learning on
your own is a recipe for disaster.
There are two general classes of soaring: thermal and slope. Thermal soaring is generally more
popular than slope soaring, primarily because thermal soaring can be done from any football sized field.
Each places unique requirements on both the pilot and plane. Many pilots enjoy both thermal and
slope flying. There are also significant subclasses in each, based on both contest and sport
rules. For example, thermal soaring includes duration, distance, speed, scale model and cross country events, to name just a few. Slope soaring includes duration, slope combat, speed, scale modeling, and much
more. All in all, R/C soaring is a very broad sport, enveloping many diverse disciplines.
Thermals are rising bubbles of air caused by the uneven heating of the ground by the sun. Thermals
can be found in any terrain, and under any weather conditions, but some conditions and terrain are
more likely to produce thermals than others. The plane is launched using
a launch system such as a high-start to an altitude of 200-1000 feet, then flown in search of thermals.
A plane in a thermal exhibits certain
subtle visible signs. With experience, thermal pilots learn to recognize these signs and
circle in the thermal to gain altitude and extend flight times. Thermal planes typically
have long wingspans, and are flown at great distance in search of lift.
For the beginner, thermal
flight times are generally only a few minutes, but with practice thermal flights of 20 minutes
to well over an hour are not uncommon. Typical thermal competition events include duration,
distance, speed, and precision landing.
In slope soaring, wind power rather than thermals are used to keep the plane in the air. For
slope soaring, you need a suitable hill or slope, with a steady wind blowing up the face. The
plane is hand-launched from the edge of the slope, and the wind rising up the slope is used
to keep the plane aloft. Finding good slopes with steady wind can be difficult in some
areas. Since slope lift is usually much stronger than thermal lift, slope
soarers tend to have shorter wings and are designed for quick aerobatic response.
Thermal planes can be used for slope soaring, but the reverse is not generally true,
since slope soarers are designed to perform in much higher lift conditions. Slope
flight times are much longer, in general, than thermal flight times.
include duration, speed, aerobatics, and even combat.
If you are serious about entering the world of soaring, here's ten quick steps to success.
All of these subjects will be covered in more detail in the chapters to follow.
- Visit the local soaring club, watch some sailplanes fly and ask for advice from club members.
- Research and purchase an appropriate trainer sailplane.
- Purchase a radio with some growth potential in mind.
- Join the Academy of Model Aeronautics.
- Joint your local club, and attend the meetings.
- Clear some space out and build your plane.
- Have an experienced flier check your progress at several stages as you build your plane.
- Select an instructor from the local club to help you learn to fly.
- Fly under the supervision of your instructor until you have soloed your plane in a variety of conditions and attitudes.
- When you've become a great pilot, take the time to teach someone else to fly!
There are four general classes for sailplanes. Sailplanes in class A and B are easier
to transport and fly from small fields, but class C and D airplanes have much better
performance overall. Most people learn to fly a two-meter airplane, and then build
other sailplanes as their skills advance.
- Class A: Handlaunch - Sailplanes with projected wingspan measuring 1.5 meters or less. These
planes are typically very light weight (< 1 lb) and are hand launched like a javelin. Because of their light-weight construction and tiny flight times, handlaunch planes are primarily for intermediate and advanced fliers.
- Class B: Two Meter - Sailplanes with projected wingspan measuring 2 meters or less. Most beginner
sailplanes are two meter ships, because these planes are small, responsive, and have reasonable performance.
- Class C: Standard - These planes have a projected wingspan of 100" or less. This class was very
popular in the 1970's-1980's as it offers a reasonable compromise between the large unlimited class
planes and small two-meter planes. Many of the legendary floater designs (Aquila, Sagitta) of the
1970's and 80's were of this size.
- Class D: Unlimited - Unlimited class sailplanes have projected wingspans over 100". The most
popular planes in this class are around 3 meters in size, (10-12 feet). Unlimited class
planes have the highest performance, and typically incorporate the most advanced features.
Sailplanes are controlled using anywhere from 2-4 control surfaces. The pilot
on the ground uses a small joystick to control these surfaces, and direct
the flight of the sailplane from launch to landing. The following controls are most
commonly used on sailplanes:
- Rudder - The rudder controls the left and right (yaw) axis of the airplane. On
beginner and intermediate planes, the rudder turns the airplane. On more advanced
sailplanes, the rudder is coupled to the ailerons to turn the plane.
- Elevator - The elevator controls the up and down attitude (pitch) of the airplane.
Pulling back on the joystick raises the nose of the airplane, and pushing forward lowers
it. On a sailplane, the elevator is used primarily to control airspeed and to
- Ailerons - Ailerons are movable surface on the trailing edge of the wing. These
surfaces move up and down in an opposite manner (i.e. right side up, left side down)
to control the roll angle of the sailplane. They are most often used in coordination
with the rudder and elevator to turn the plane.
- Spoilers - Spoilers are surfaces that extend from the top center of the wing to create turbulence and drag. They are used primarily
for precision landings. The typical sailplane has a very shallow glide angle
and is difficult to precisely land. Spoilers (and flaps) let you adjust
the glide-path for precise spot landings.
- Flaps - Flaps are movable surfaces on the inner trailing edge of the wing that
move together to change the shape of the wing. They are typically
extended downward to slow a plane down for landing or thermaling, and reflexed
upward for additional speed. Flaps give the advanced pilot more control over the speed and lift characteristics of the wing for better overall performance.
In addition, flaps can be extended nearly 90 degrees to act like spoilers for precision landing.
A polyhedral, two channel (rudder, elevator) sailplane like the Gentle Lady is best for beginners!
There are two general sailplane configurations: polyhedral and straight wing. Polyhedral
planes have three angles in the wing, that allow them to be turned using only
rudder and elevator (two channel) control. The polyhedral angle in the wing provides
inherent stability to the plane, making these planes easier to fly.
They use only the rudder to turn the plane.
Straight wing airplanes have little or
no angle in the wings, and instead rely on ailerons coupled with the rudder to turn the
plane. These planes usually incorporate rudder, elevator, aileron and flaps for full
four channel control. Straight wing airplanes generally perform slightly better on launch and in wind, but are also
harder to fly since they do not have the inherent stability of a polyhedral wing.
By popular convention, polyhedral planes are affectionately called gas-bags for their slow fight and gentle disposition.
Straight-wing and aileron controlled planes are called lead-sleds
because they are generally heavier and fly much faster.
Sailplanes designs can also be characterized by pilot level. The advanced competitor generally
flies a much more advanced design than the beginner. Pilot skill matters more than
plane choice, so don't get too caught up in the plane of the month fashion club. Instead,
choose an airplane that challenges your skills, but is appropriate for your current skill level, then fly it until it won't fly anymore.
The pilot who is more experienced will generally beat the pilot with the fancier plane.
Guidelines for selecting an airplane
are included in later chapters, but general characteristics that distinguish beginner, intermediate
and advanced planes are introduced here.
Beginner sailplanes are designed to be inexpensive, slow, tough,
responsive, and very stable. Typically they are
two channel (rudder and elevator) planes made of traditional built-up wood construction or Almost-
Ready-to-Fly (ARF) foam. Most beginner planes have two meter wings, and may incorporate
features like rubber band wing attachments to reduce damage from crashes. True beginner
airplanes can be distinguished by their "flat-bottom" airfoils. A flat-bottom airfoil flies
at slow speed compared to a more advanced airfoil, making the plane easier for a beginner to fly.
If you have never flown
before, a beginner plane is a must. Flying an R/C sailplane is much harder than it looks, and crashing
a sturdy, slow flying beginner's plane is much better than crashing an expensive, light, fast flying
A revolution in beginner technology took place in 1996-1997 with the introduction of EPP foam thermal and slope trainers.
These planes are made of special foam that is wrapped with packing tape to create a nearly indestructible airplane.
The technology was originally developed for slope combat airplanes, where opponents intentionally smash their planes together in an attempt to force each other into the ground.
These foamies make perfect trainers since they will withstand the heavy punishment an average beginner dishes out.
In addition, foamies are easier to build than traditional sailplanes.
With a foamie trainer, the beginner will spend a lot more time flying and a lot less time building and repairing - a double advantage!
Intermediate sailplanes are generally moderately expensive, faster, responsive, and slightly less stable.
These planes usually have additional controls such as ailerons, flaps or spoilers to accurately control airspeed
and altitude for precision competition and landings. The added speed allows these planes to
cover a larger area in search of lift, and handle high winds better. Intermediate planes often have
stronger, more accurate wood over foam core wings, with carbon fiber reinforcement to allow for
more violent zoom launches. The added speed and control of these airplanes allow a pilot
who has mastered the basics to expand their skills for better overall performance. Intermediate
planes are also the most popular planes for sport flyers who want good performance without
investing a bundle.
Advanced sailplanes are generally very expensive, fast, unstable, and responsive. These planes
are designed for advanced competition, and typically require expensive computer radios to control
the plane. A minimum of four channels (rudder, elevator, aileron and flaps) is used with
as many as six separate micro-servos. Construction varies from pre-sheeted wood over foam to
the most expensive kevlar and fiberglass layered planes. These planes are designed to handle the
strongest zoom launch, and are also engineered for speed and distance events.
The fast speed and computer control
allow these planes to launch higher and search vast distances for lift, as well as achieve blistering
speed runs. The features of these advanced planes are only needed for serious competitors
with years of experience, but offer the highest performance if used properly.
Modern radio control systems are truly a miracle in miniaturization. Weighing as little as
4 ounces, these systems let you control your sailplane beyond the point where you can
safely see it. Complete radio systems cost anywhere from $60 to well over $1000, but all
radios have the following basic components.
- Transmitter - A transmitter is the system you hold in your hands to fly your sailplane. Most sailplanes transmitters are rectangular, with two joysticks on the front and a long
antenna coming out of the top of the box. To fly the plane, the pilot manipulates the
controls, which the transmitter then relays to the plane. All modern R/C systems are proportional, which means if you move the joystick a little, the control surface on the plane moves roughly the same amount.
- Receiver - The receiver is the corresponding controller in the airplane. Receivers are typically small boxes, about the size of a business card and 3/8" to 1/2" deep, with an antenna wire trailing about 24" from it. The receiver intercepts the signal from the transmitter, decodes it, and controls the mechanical servos, which directly push or pull
the sailplanes control surfaces.
- Servos - Servos are small mechanical motors which precisely rotate in response to signals from the receiver. Servos are connected mechanically with pushrods or cables to
the control surfaces of the plane. Each plane has from two to six servos. Each servo occupies one "channel" of the radio.
The number of channels, and servos, determines how many control surfaces can be controlled. Servos are available in different sizes and power levels for different
applications. Standard and micro-sized servos are most commonly used in sailplanes.
- Batteries - In the airplane, and transmitter are small battery packs which power
the transmitter and receiver. Typical rechargeable (NICAD) battery packs are designed to
operate anywhere from one to four hours on a single charge. This is typically more than
enough for an afternoon of flying. Cheaper radios use standard AA or AAA batteries,
which must be replaced after a few afternoon's of flying. It is always better to purchase
a system with rechargeable batteries if you can afford it. These batteries can be recharged overnight using a small charger that comes with the system.
Radios generally have a fixed frequency, also called a channel assigned to them.
Different radios are on different channels, allowing more than one plane to fly
simultaneously. In the United States, 50 channels, numbered 11-60, are allocated by the
FCC in the 72MHz frequency range for model aircraft use. For most radio systems, you specify the
channel when you purchase the radio system, and will use than channel as long
as you own the radio. For most radio systems, you must send the transmitter to
the manufacturer to change the channel. Some advanced computer radios let you change channels by
purchasing an additional transmitter module and receiver crystals, but these
systems generally are very expensive. If you are going to purchase a new radio,
it is a good idea to check with your local sailplane club first. Many clubs
keep lists of frequencies for each member, and can tell you which
channels are open for use. Obtaining your own channel is always best, since
you don't want to have to take turns with someone else on the same
channel when you fly.
in the US, laws governing radio control changed in 1991 from wide band
systems to narrow band. All systems manufactured since 1991 are designed for
the new 50 channel narrow band frequencies. You should, however, avoid
using any pre-1991 radio control system unless it has been upgraded to the
1991 standard. The pre-1991 systems use the same frequency band, but each
channel in the old band occupies several channels in the new band. If you use
an old system, you could potentially shoot down several of your friends who
are using nearby narrow band channels. Most 1991 compatible systems are
identified by a gold sticker on the receiver.
Clearly, if two pilots are flying on the same channel, the result will be disaster.
At most club flying sites, and all competitions a simple method is used to control
frequencies so two pilots do not conflict. If only a few pilots are at the field, simply
cross checking with the other pilots to determine conflicts may be sufficient. If a large
number of pilots are flying, clothes pins labeled with each channel number are
used. The rule is simple, if you don't have the clothes pin with your
channel number clipped to your
transmitter, you can't turn the radio on. At very large contests, transmitters are
actually impounded in a central area, and released to the pilot only when it
is the pilot's turn to fly.
Interference can also be a problem if you are flying alone. Someone could be flying
planes at a field nearby, and still cause trouble for you. Its a good idea to know which
fields are within a few miles of your chosen flight zone. As extra insurance, I always
turn the receiver on for a minute or two before turning my transmitter on
at unknown sites. If the controls start moving or seem excessively noisy, I will
stop and try to find the source of the problem. Its better to lose an hour of
flying than lose an airplane.
There are four general types of aircraft radios. They vary in functionality from the simplest two channel radio
to the most expensive computer radio. A brief description of the four types follows:
- Two Channel Systems - Two channel radios are very inexpensive, priced at less
than $100 for a complete system. Unfortunately, most two channel systems have two
control sticks, one per channel. Typically the rudder control is on the right joystick,
and the elevator is on the left. This type of system is very difficult to learn and control
because you need to use and coordinate both hands to fly. Slightly more expensive
four channel radios have both rudder and elevator on a single joystick on the right side,
making it much easier for the pilot to control. Also two channel systems rarely come
with rechargeable batteries, meaning you must constantly buy new batteries. For a few
dollars more, an inexpensive four channel system is a better buy.
- Four Channel Radios - Simple four channel radio systems are available for less
than $150 and are a great investment for the beginner. Four channel systems offer
the standard two stick control system, rechargeable batteries and three servos. A four channel system of this type can be used to control beginner to intermediate planes easily,
and can even be used on some advanced sailplanes. For a beginning or intermediate
pilot, this type of system offers the most bang for the buck.
- Mixing/Computer Radios - Basic computer and electronic mixing radios offer
many of the same features. The most important of these is the ability to electronically
mix two radio channels together. For example, when the pilot extends spoilers or flaps,
it tends to pitch the airplane either up or down. Using a mixing radio, the elevator
can be mixed with the flaps or spoilers to automatically compensate so the plane
does not change pitch. Another example is V-tail mixing, where a V-tailed airplane
needs mixing of the two control surfaces to provide separate pitch and yaw control.
Rather than mechanically link the two channels, a mixing radio can mix them
The limitation of these radios is that mixing is typically allowed
only on preset channels and in preset configurations. They offer a reasonable compromise
for intermediate pilots who need mixing features but don't want to spend the
extra money for a sailplane programmable computer radio. Typical prices for
new systems are in the $200- $250 range.
- Sailplane Programmable Radios - The most capable and most expensive radios
have dedicated sailplane functions, including programmable mixing. These radios
directly support many of the most common sailplane functions, and also have
programmable mixing functions to allow any channel to be mixed to any other.
This gives the pilot the most flexibility since any function can be assigned to any
switch or control. In addition, each control and mixer is electronically adjustable,
allowing the radio to be tailored to precisely trim the airplane. Typically these
transmitters can store three or more plane configurations in memory, letting
you switch between them at will. Naturally, these are the most expensive radios
to purchase, but you can often find used systems at a discount price, making them very attractive. Fully programmable sailplane radios cost $400- $1000, but used transmitters
are available for as little as $150.
Three different modulation methods are used to encode your radio signals. These are,
in increasing order of price, Amplitude Modulation (AM), Frequency Modulation (FM), and Pulse Code Modulation (PCM).
AM and FM are essentially the same methods used in AM and FM car radios, but on
a different R/C frequency.
The vast majority of radios in use today are FM, as FM is reliable and relatively inexpensive.
FM radios are less susceptible to noise and interference than their AM counterparts.
In addition, most FM receivers are dual filtered, adding an additional layer of noise
suppression. PCM radios offer even better noise rejection that FM, but at a significantly
higher price. Unless you are flying a very expensive (> $1000) airplane, you will
find that FM offers very good noise rejection and range at a reasonable price, making
it the radio system of choice for most pilots.
There are six generally accepted methods for getting your plane into the air. For slope soaring the plane is hand-launched from the top of the slope. For thermal soaring,
the plane is usually towed into the air using a towhook on the bottom of the airplane
under the wing. Each method will be covered
in detail in later sections of the book, but a brief summary is included here.
- Hand Launch - Hand launching is simply giving your airplane a good solid heave to
achieve flying speed. This method is used primarily for slope and hand-launched (class A)
gliders, but you can hand launch larger planes to test the trim and provide landing practice.
- High-Start - A high start is nothing more than a really big rubber band. A standard
high-start consists of 100 feet of surgical tubing and 200-400 feet of nylon or
monofilament string. One end is staked down, the rubber is stretched 50-100 yards, and
the towhook of the airplane is connected to the other end. The high-start pulls the plane
up to a height of 200-400 feet, and a small parachute returns the high-start to the
- Electric Winch - A winch is an electric version of a high-start. Rather than rubber,
an old Ford starter motor is used to launch the plane. The winch sits in front of the pilot,
and is connected with nylon or monofilament line through a pulley as much as 1000 feet
away and back to the airplane. The pilot controls the speed of the winch using a foot
or hand switch by pulsing the motor. The main advantage of the winch is faster pulling
speed and the ability to control launch speed. Generally a winch will launch a plane
much higher than a high-start, with launch altitudes of 500-1000 feet possible.
- Motor Assist - Sailplanes can be equipped with small gas or electric motors. Though
sailplane purists will scoff at you, this is a good method for achieving excellent
thermal altitude. Electric sailplanes are generally more accepted than gas because they are
quiet. The main disadvantage of motors is their weight. Batteries and gas engines are
heavy, and this hurts your thermaling performance. Tiny, 60" 400-speed thermal planes
have caught on in some parts of the country because they are inexpensive, and small
enough to throw in the trunk.
Since you can fly a small electric from most any
field in minutes, they are very popular for lunch break and after work flying.
- Hand Tow - If you have an athletic friend or child, you can hand-tow your plane.
This method has gained dramatically in popularity in recent years because of a new
international thermal competition called F3J, which specified hand tow launches.
The specified towing equipment is 150 meters of monofilament or nylon line.
You can achieve spectacular launches using hand-tow of 500-800 feet, and the
equipment is extremely cheap.
- Aero-tow - Aero-tow uses a radio controlled powered aircraft to tow the sailplane into the air.
This method is most popular for scale sailplanes since it duplicates the majesty of full-scale aero-tow.
This method is the most demanding in terms of equipment, since the powered plane must be of sufficient size and power, and both planes must be equipped with releasable towhook.
It is also very demanding for both pilots since the tow must be made at the correct speed and attitude to avoid a variety of possible problems.
Still, for the scale purist, aero-tow is the ultimate launch!
Part 1: Soaring for Beginners | Contents | Chapter 2: Getting Started
Copyright 1997-1998 Bradley J. Smith
All Rights Reserved