by Lawrence Doan
"Hey man, this
doesn't sound like the rule for a loop."
- Richard Bach, Jonathan
If you're reading this, chances are
that you already know that you want to learn to fly RC
sailplanes. You've seen someone fly, or read about it.
You've looked around on the web, and found rcgroups.com, and
this website. There's so much information out there, but how
do you really learn to fly?
There's an excellent (and free) book on this subject: The Sailplane and Soaring Manual
The book is out of print but you can find used copies on line at
And you can view it online:
Go ahead and do that. Then come back.
Ok, you're back. The book is slightly dated in that it doesn't
talk about the latest radio technology, but the sailplane doesn't
care what radio is in it, so that's not a problem.
The Sailplane and Soaring Manual is comprehensive in sailplane
construction, radio installation, trimming and flying and it's hard
to beat. What we'll do here is supplement it with some things to
do *before* you get that first airplane.
"This is what we call a wing."
Learning RC soaring, like anything else, is really learning a new
language. There are words to learn - wing, center of gravity,
thermal, dihedral - but there's also a grammar to learn to
connect those words together. What is sailplane grammar?
You'll need a tool to learn it, and it should be the first purchase
you make in the soaring hobby:
Introducing the Humble Jetfire
The Guillow's Jetfire
has been around seemingly forever. Available
in toy sections and hobby shops everywhere, it costs from $2-$5. In
the Seattle area, Galaxy Hobbies
, R/C Hobbies
, and Snapdoodle Toys
all carry them.
Fred Meyer has them seasonally in spring and summer, and even ACE
hardware stores have been known to keep them in stock.
Go get one. Heck, get four. But make sure they are Jetfires, and
not Starfires or Sky Streaks or anything else.
The Jetfire consists of a wing, a fuselage, a vertical tail and a
horizontal tail. It also includes a pilot figure/canopy. These
all function (except for the pilot) as they do on every airplane
Assemble your Jetfire according to the instructions. PULL the wing
through the slot. Adjust the wing to the forward edge of the slot.
Place two fingers under the wing, one on each side of the fuselage.
Find the point where it balances and the fuselage is level. Mark
that on the fuselage with a pen.
Similarly, balance the plane and see if it wants to tip left or
right. Slide the wing slightly to the right if it tips left, and
vice-versa. Don't worry about getting it perfect, but make note
of a heavy wing. (If it's really out of balance, try another Jetfire.
It's rare, but it happens.) Mark the wing so you can put it back
if it gets bumped out of place.
You have now found the Center of Gravity (CG) of your plane - the critical
balance point. You'll hear a lot of it later, where it should go
and all that. Don't worry about that now. Trust that that Jetfire
has it in the right place. Later, trust that the designer of your
RC plane has marked the CG in the right place, too.
The Art of Throwing a Glider
The Jetfire will teach many things, but the first lesson will be
how to throw a glider. A good launch guarantees a successful flight.
This is because _gliders fly themselves._
Your job as pilot will
be to guide it to lift and to a safe landing. Let the airplane
take care of the flying.
The trick to throwing a glider is to push it straight ahead, and
slightly down, without any tendency to spiral it like a football.
Hold the Jetfire under the wing near the CG with thumb and forefinger.
Hold it gently. Raise it to eye level, keeping your forearm vertical.
Make sure the wings are level. Bring the plane back towards you
by bending your elbow only, then throw the same way - elbow only.
Darts players will know what I mean. Don't snap your wrist. Release
the glider with the wing and fuselage level.
The glider should fly straight away from you. If it falls to the
ground, throw harder. If it starts to loop the loop, throw more
gently. If it slams into the ground, you're letting go too late
or holding on too tightly.
If the airplane gets knocked out of alignment, be sure to put it
back before you throw it again.
Practice until you get a consistent flight, even if it curves to the
left or the right. As long as you get the same flight over and
over, you're doing it correctly.
When you find the right throw you'll find that you can feel when
it just wants to lift out of your hand. You've found the _trim
of the Jetfire - the speed where it naturally wants to glide.
Any faster and it will climb, and slow down. Any slower and it
will fall to reach that speed. In either case, if it doesn't hit
anything, it will settle down to that same trim speed.
The Science of Trimming an Airplane
Now that you have a consistent launch, it's time to correct any
tendency for the glider to turn. Note which direction it turns.
Make sure your launch doesn't favor one wing down or the other.
Hold the plane at eye level and look at it directly nose on. Moving
only your eyes, look at each wingtip. If you can see the bottom
or top of one wing more than the other, you have a warp that needs
correcting. Ideally you want them even with the center of the wing,
but the important thing is that they be equal.
Breathe on the wing like you would to fog up a mirror, while twisting
it in the desired direction. Hold it for a few seconds, and then
check the result. Repeat as needed. Usually only a small change
Once you have the plane flying straight and true, launch it with
one wing down, and watch as it turns. It may keep that wing down,
or it may level out, or it may continue to drop a wing. Try it in
each direction. If it drops a wing one way, but levels out the
other, you still have a little warp. I find that most Jetfires get
to a point where they will hold a turn one way, but level out the
The more bank angle you start with, the tighter the circle. You'll
find that the plane will descend more in a turn if you don't add
force to the throw. Add a little more force and a little more bank
angle, and soon you'll have the plane circling back to you. Add more force
with the wings level and it will loop the loop.
Here is an important lesson: A turn is really a horizontal loop.
There is one difference however. Take the rudder off the Jetfire,
and do a straight launch. With a little care it will fly fine
though it may skate sideways a little. You can loop it. Now try
your circle. Didn't work so well, did it? What happened? The V
shape of the wings is called dihedral.
Anytime the plane tries to
fly sideways, dihedral will raise the leading wing. The vertical
tail tries to keep the plane from flying sideways. In a turn, the
plane wants to fall and fly sideways towards the ground. This
raises the low wing and the plane rolls over the top. With the
rudder, the amount of sideways flying is reduced. The right amount
of rudder and dihedral will cause the plane to slowly return to
wings level. (If you put a bigger rudder on a Jetfire, you can
make it spiral into the ground.)
End of Lesson One
If you've gotten this far, I hope you have had some fun playing
with gliders. After all, this is about fun. You've learned the
parts of a plane, and how it wants to fly. You have a good basis
for launching your first RC sailplane, and you know what to look
for on its first flights. You've learned the basics of trimming.
You know that a glider will fly itself - the Jetfire has no radio.
It will turn, and glide, and loop the loop and even land itself
when it is properly trimmed.
What's the next step? Take all the advice I ever ignored:
1) Don't teach yourself to fly. (But if you must, do it with a
Jetfire and the Sailplane and Soaring Manual.)
2) Join the AMA
. The magazine is great reading and the insurance
is nice too.
3) Start with a floater glider like one of these:
And of course, never ignore having fun.