This is an article which originally appeared in the Louisville Area Sailplane Society newsletter The LASS word. It contains a particularly simple description of winch launching as well as general hints on thermal flying.

 

Tips For New Folks - Part 2 - M. Scott Borden

(Last month Scott discussed a variety of designs and airfoils and their

merits. Scott also discussed what "powers" our models. This time he

covers our flying with "Getting them up and keeping them up". - Ed )

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Editor's Note: I am no expert at teaching new folks how to fly R/C

sailplanes. There are better flyers and more patient, personable

teachers, and much more gifted writers, than I am. There are a host of

books on the subject. I recommend Dave Thornburg's OLD BUZZARD GOES

FLYING, both the video, and (especially) the book. KALBACH BOOKS has

many titles on R/C soaring, too. I suggest new folks get these books and

study-up on all the fine details I won't cover. The purpose of this

article is to pass on some practical knowledge to new folks to help them

understand these wonderful, silent flying machines more quickly. Again

these are my thoughts, beliefs, solutions and experiences; some are

actually based in fact! I hope they help you.

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TOWHOOK position is IMPORTANT for maximum LAUNCH ALTITUDE. The closer

the hook is to the C.G. the higher the launch, but the sailplane becomes

UNSTABLE. Again, a compromise between stability and high altitude is

necessary. In general, tow hooks should be located about 1/4-inch fwd of

the C.G.. A really great way to determine if the hook is, in fact, fwd

of the C.G. is to hang the sailplane upside down with a piece of

towline, or other strong cord, attached to the towhook. If the hook

position is correct, the sailplane will hang tail LOW.

oNew Folks will most likely use a HIGH START first to launch their

sailplanes. For winch launches it's important to remember what the pull

of the High Start feels like just before you launch the sailplane. Why?

The winch intimidated me because I had no idea what to expect. Then,

Jeff McComb instructed me to take-up enough slack in the winch line to

simulate the pull of a High Start before launching the sailplane. It was

one of the most comforting pieces of advice I'd ever received! I prefer

winch launching over any other method because of the quality of the

height of the launch and the winch's instant adaptability to different

field lengths.

When launching, whether from a High Start or WINCH, THROW THE SAILPLANE

HARD to make sure the sailplane reaches flying speed before the nose

rotates up into launch attitude. Forgetting this may cost you your

airplane...

The winch is powerful enough to fold wings if you do not control its

pull. The pull is controlled by (1) the frequency the winch foot pedal

is tapped, and (2) the duration the winch foot pedal is held down/on. In

general, the frequency is 2 to 3 taps per second with short duration.

For heavier sailplanes, in basically calm conditions, the frequency is

about 1 to 1.5 taps per second with longer duration between taps. In

wind conditions, most sailplanes will kite-up on launch with 1 to 1.5

taps per second with VERY short duration. A good rule of thumb, for me,

is to launch the sailplane with just enough pull to make it climb well

and NO MORE! WATCH THEM WINGS!

FAILURE TO TAP THE PEDAL AFTER THROWING THE SAILPLANE RESULTS IN A NASTY CRASH!

At first its kind of like patting your head and rubbing

your stomach at the same time, but it becomes second nature in short

order. A good way to practice tapping is to operate the winch while a

trusted fellow glider guider flies your sailplane up the launch path.

Try it.

Winch line POP OFFS can be caused by (1) too much up elevator, (2) too

much launch flaps, (3) mounting the towhook too close to, or aft of, the

C.G. or (4) any combination of these factors. Building your sailplane

according to plan will minimize pop offs. Of the pop offs I've seen, all

of them occurred at sufficient altitude to recover and land. Recovery is

fairly simple because pop offs usually cause the sailplane to loop. If

the sailplane looks like it's just very nose high, but not entering a

loop, momentarily apply FULL down elevator (the sailplane will probably

stall) to lower the nose and recover flying airspeed, then level-off for

landing. If the sailplane is obviously in, or about to, loop apply up

elevator to complete the loop, level off and land.

Steer the sailplane up the launch path toward the winch TURNAROUND

pulley. When the sailplane reaches the top of accent, in many cases the

winch line will simply drop off the hook. Sometimes you may have to coax

it off the hook with a slight dive and pull up to level flight. If the

winch line becomes stuck to the aircraft (I've seen it happen more than

once) DON'T PANIC! Just turn one way or the other and make gentle, small

-to-medium circles down to a landing. Don't fly in one direction very

long, for obvious reasons.

Once the aircraft is free of the winch line, and assuming it has been

properly hand tossed and adjusted by an experienced fellow glider

guider, let her settle into that STRAIGHT AND LEVEL, HANDS-OFF, minimum

sink airspeed glide. Fly left or right at about a 30 to 45 degree angle.

Look at the ATTITUDE, the position, of the fuselage relative to the

horizon. NOW BURN IT INTO YOUR MEMORY; whether turning, flying straight

and level, climbing in a thermal, or gliding to a landing, maintaining

that fuselage attitude controls minimum sink airspeed. Pull the nose up

and the sailplane will stall at stall airspeed. Push the nose down and

the sailplane will accelerate rapidly out of minimum sink airspeed; too

much nose down for too long and the wings will blow off the airplane.

MAINTAIN FUSELAGE ATTITUDE!

At some specific airspeed below minimum sink airspeed your sailplane's

wings stop generating Lift, or STALL. Properly designed, with either

Mechanical or Aerodynamic wing WASHOUT, the sailplane stalls basically

"straight ahead". Washout prevents TIP STALLS, nasty critters which can

destroy your sailplane if it's close to the ground...like on launch...or

turning in the pattern for landing; if the wingtips stall first, the

sailplane rolls left (or right) instantly, and pitches sharply nose

down.

Luckily for us, the sailplane responds to a stall by dropping its

nose, exactly the direction the nose should go to regain flying airspeed

(remember Gravity?). As airspeed is regained, Lift regenerates rapidly,

pitching the nose up, causing another Stall; this porpoising continues,

in most cases, until the sailplane hits the ground, unless you

intervene. Assuming your sailplane has enough altitude, Stall recovery

is relatively easy, whether flying straight and level or turning in a

thermal or landing pattern. BEFORE the next Stall occurs, apply DOWN

elevator. NOT TOO MUCH DOWN, JUST ENOUGH, to place your sailplane's

fuselage back into that Minimum Sink Airspeed Attitude you have burned

in your brain. Then return the stick to neutral; if she looks like

she'll pitch her nose up again, PULSE down elevator until she settles

into hands-off flight.

Turns, especially the CONSTANT RATE TURNS used in THERMALLING, can be

relatively easy to perform. SET THE BANK ANGLE, by moving the stick to

the left (or right), until the angle is established. Then return the

stick to neutral. If the angle is too much, move the stick opposite the

direction of the turn to flatten the angle, then return the stick to

neutral. If you hold the stick in the direction of the turn, the

sailplane will ROLL in the direction of the turn and will rapidly begin

a downward spiral. When in a turn, aircraft tend to enter a slight dive.

To arrest the dive, maintain fuselage attitude and minimum sink

airspeed, and help the sailplane GROOVE THROUGH THE TURN, immediately

apply slight up elevator as the stick is returned too neutral. The up

elevator control input tends to tighten the turn, so opposite rudder is

necessary to flatten the bank angle. BANK AND YANK!

Flying is a careful balance of (1) forward and aft stick movements to

control the airspeed of the sailplane (by controlling the attitude of

the fuselage), mixed with (2) left and right stick movements, to control

the angle of bank of the wings in turns. As your experience grows you

will notice the stick is constantly moving...

Most pilots find turns in one specific direction to be really

uncomfortable feeling (for me it was right turns), so they tend to turn

only one way. To over come that, practice, over and over, turning in the

uncomfortable direction. It really works!

Wind Tip Number 1 - AIRSPEED and GROUNDSPEED ARE NOT THE SAME. Once

the sailplane is free of the winch line it flies at whatever AIRSPEED

you have it trimmed for. However, depending on which way the wind is

blowing, the sailplane's GROUND SPEED, the speed at which the sailplane

appears to be traveling over the ground, ranges from really slow (the

sailplane fly into the wind) to really fast (the sailplane flies with

the wind)! Many pilots panic when the sailplane's Ground Speed is really

fast by applying Up-Elevator control in a vain attempt to slow the beast

down; if the sailplane is flying at an Airspeed just above Stall

Airspeed, the sailplane will Stall. If she's too close too the ground

and in a turn, well..., hope you have another sailplane to fly! Don't

attempt to fly the sailplane slower, just think faster than she's

flying.

Wind Tip Number 2 - The wind always blows at some speed. When you

thermal, the sailplane will drift with the wind. I'll leave the whole

subject of thermaling to Dave Thornburg, but I will cover one topic;

maintaining a constant rate turn in a breeze. Because the sailplane is

constantly turning into and out of the breeze, the sailplane will tend

to BALLOON up as it turns into the wind and will tend to accelerate

rapidly (and appear to sink) as it flies with the wind direction. When

turning into the wind, you may have to apply DOWN elevator to maintain

fuselage attitude. When turning with the wind increase bank angle to

maintain the integrity of the circle. As previously stated, your stick

will be constantly moving...

Whether your sailplane is at 1000 feet altitude or 10 feet altitude,

fly your sailplane exactly the same way. The only difference is you have

less altitude in which to make mistakes. Near the ground, plan ahead,

make shallow turns, and DON'T EVER TRY TO HOLD THE AIRCRAFT IN THE AIR

BY APPLYING UP ELEVATOR!!! MAINTAIN FUSELAGE ATTITUDE. Plan your landing

ahead of time and fly a rectangular approach path, just like full size

aircraft. Your fellow glider guiders will have you enter a DOWNWIND LEG,

BASE LEG and FINAL APPROACH LEG, if they're experienced pilots. Landings

should be made flying into the wind to slow down the GROUND SPEED of the

sailplane. Downwind landings can damage or destroy your aircraft. Fly

your sailplane to within a few inches of the ground, gently level off

and let her settle onto the ground. Save those hard contest landings for

next season!

BEWARE THE DOWNWIND TURN CLOSE TO THE GROUND!!

That's about it, folks. If I think of any more, I'll put them down and

pass them on, to you.

See you at the field!

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