RANDOM NOTES ON HAND LAUNCHED GLIDERS (06-04-21)
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LAUNCHED GLIDERSと言う記事が出てい ます。中身はハンドランチグライダー（ＨＬＧ）の飛ばし方・調整法・製作／設計の
ヒントであり、長短織りまぜて３５項目あります。読んでみたところHLGにも紙飛行
機にも（手投げ・カタパルト共に）有益そうなので８番当会議室への転載許可を求め
たところ、give and takeを条件に快く了承して頂きました。
ヒント（１）からヒント（１５）までは設計・製作のヒント、ヒント（１６）から
ヒント（３５）までは投げ方や飛行調整です。ほとんどの内容がＨＬＧだけでなく
カタバルトグライダーや紙飛行機にも適用出来ますからぜひ試してみて下さい。結
果が出たら８番会議室または松本(QWE01503)まで感想をお知らせ下さい。
翻訳は別資料として掲載しています。
RANDOM NOTES ON HAND LAUNCHED GLIDERS
By Jerry Barnette* - Picked up over the years from here and there * With apologies to anyone whose comments may have been incorporated, but attribution has been lost or forgotten. NOTE: All of the comments are addressed to right-handed folks; reverse for left-handed throwers. :) ---------------------------------------------------------------------------
1* Do not use a large stab or rudder. If
the model is too stable, it will not make
the transition quickly and without altitude
loss. In handlaunch, the transition is everything.
If the stab is too large, it will tend to
let the plane fly even though it is really
badly out of longitudinal (fore and aft)
trim. You will wonder why adjusting the stab
does not bring better flights, when the glider
is basically out of balance. Too large a
stab will keep the HLG from any snap recovery
and the plane will fly through at the top
of the launch. If too small, the stab will
sink out at gliding speeds because some weight
is carried by it.
2* The stab should be tapered from the center
outwards to approximately 1/32" at the
tips. The stab leading edge may be relatively
blunt. You do not want a stab that overlifts.
3* Some people prefer an wing airfoil with
a thin section and a high point 40% back
from the leading edge. This type of section
has less drag than a thicker wing section,
but will result in a faster glide and less
stability. A thicker section with a high
point 25% to 30% from the leading edge may
have slightly more drag, but also a better
glide and will be more stable, especially
in windy weather.
4* In general, the rudder is too effective
at high speeds, and not effective enough
at low speeds. The solution is to use stab
tilt for the glide turn, keeping just enough
rudder for a transition.
5* Offset the centerline of the wing 1/16"
to the left of the centerline of the fuselage
(SWEEPETTE).
6* Cut out the fuselage slightly over-size
to allow for stress relief in the tailboom
area, then sand it down to the final shape.
7* Arrange the wing so that the heavier panel
is on the inside of the glide turn. Put built-in
washin in the tip of the inside panel. The
washin does two things; it makes the panel
stall first, dropping the model into the
core of the thermal; and it keeps the plane
from spiralling too tightly once it is in
the thermal.
8* Resist the urge to make round edges on
the fuselage! Rounding saves very little
weight but seriously diminishes strength.
9* Before the last coat of dope on the stab
and fin, apply a strip of lightweight Japanese
tissue to the rear half of both sides of
the fin. Also, apply a 3/4-inch wide strip
of tissue to the rear of the stab; top only
on the left, and bottom only on the right.
Apply the tissue with thinner. These tissued
surfaces will be much easier to adjust later
for flying trim.
10* Use white glue for attaching the stab
so that it may be easily removed for adjustments.
11* John Oldenkamp, on his ZWEIBOX, tapers
the 1/4" balsa fuselage on the right
side only to approximately 3/32" X 1/8"
at the extreme aft section. This taper, plus
the airfoiled fin (flat on the left side),
gives an automatic left turn. John glues
the fin onto the side of the fuselage instead
of on top.
12* Bias-cut the finger rest from 1/4"
X 1" trailing edge stock. The grain
ends up in the proper direction and will
take very little work to finish.
13* The POLLY uses built-in rudder offset,
1/8" over 14.5" or 0.5-degrees.
The POLLY does not use stab tilt. POLLY does
not fly 0-0, but uses some incidence in the
stab as a margin of safety of an off-launch.
The BLACKJACK design by Larry Sargent also
mentions incidence as one of the best kept
secrets in HLG flying; it helps in the rollout
and helps to avoid the straight up/straight
down flight patterns. Use 1/32" to 1/50"
of incidence at the wing leading edge.
14* Tom Peadon (U.S. KID) recommends that
the stab be 1/2" below the level of
the wing. He can't give a good aerodynamic
reason, but it has been proven over and over
when he didn't adhere to it.
15* Kit Bays uses a semi-symmetrical airfoil
on heavier, windy weather HLGs. This type
does not glide very well in still air, but
it gives penetration and stability in the
wind.
16* Control glide turn with stab tilt.
17* Control climb pattern with rudder.
18* The four basic adjustments for HLG: A
rearward center of gravity and zero decalage
(no incidence in wing or stab) gives a loop-free
launch. Slight left rudder provides launch
turn. Stab tilt for left glide turn. Washin
in left wingtip prevents spiral dives.
19* When a handlaunch goes straight where
you point it, and then fails to make a transition,
it is only a tweak of up elevator away from
perfection.
20* If the plane turns too tightly in the
glide stick some clay on the right wing tip
and check the alignment of the rudder.
21* If the model tends to climb in a wide,
flat circle, you can probably counteract
this by warping the trailing edge of the
stab down, warping a slight part of left
rudder, and throwing with more of an overhead
motion.
21* Basic Safe Trim: Left glide turn in stab
tilt, wash-in of the left main wing panel,
slight left rudder. May also skew the wing,
right wingtip forward, to help the left-turning
transition. Similarly, offsetting the wing
(about .06") to the left helps save
tip weight and bending. Bend wash-in into
the left wing progressively from none at
the wing root to about 1/16" to 3/32"
at the polyhedral break (none in the tip).
Bend in equal amounts of "up" on
both sides of the stab until the glider has
a slightly stalling glide. Put in enough
stab tilt to give a hint of left turn when
hand gliding. Properly trimmed, the glider
will do a 220-degree to 270-degree climbing
turn, and then drift gently into a left glide
turn.
22* Having the model pointing downwind after
the transition will help keep the glider
from stalling as its airspeed decreases.
You may notice that planes that transition
facing the wind tend to stall and lose altitude,
especially if it is windy. Having a downwind
transition will also allow you to wait longer
before throwing into a thermal.
23* Symptom: instead of spiraling around
in a smooth climb, the HLG just slow rolls
in a more or less straight line. Problem:
the glider is shy on "up". Cure:
add more up in the stab (leave center of
gravity as on plans). This will make it climb
more quickly and roll more quickly. Take
out stalling in the glide with stab tilt.
An incorrect launch does not usually cause
this problem.
24* Symptom: the model spirals around only
about 90-degrees; then the wings level and
the model noses up into a stall. Problem:
the model was either thrown with too much
bank or has too much "top" rudder.
Cure: take out left rudder and/or add more
wash-in to the wing. Bank the model less
or launch more skyward. Sometimes more "up"
may be needed. The glide circle may be readjusted
with stab tilt if necessary.
25* Symptom: the model patterns very tightly
or loops. Problem: the model has too much
"up", or was thrown with too little
bank or too much skyward. Cure: take out
some up. Open the glide circle by backing
off the stab tilt. Throw at a little lower
angle or with a bit more bank (go easy).
If the model has a tendency to spin-in in
the glide, add more wash-in to the wing.
26* If the model tries to spin in on the
glide, add washin on the left wingtip. If
the spin persists, reduce the left rudder
tab.
27* If the glider goes way up, does 180-degree
vertical reverse, slams straight back to
earth, then add more "up" to the
right side of the stab.
28* Problem: the model climbs to the right,
but stays in the bank too long and loses
altitude, still in a banked attitude before
leveling off and turning left. Cure: too
much decalage (angular difference between
angles of attack of wing and the stab). Warp
stab trailing edge down; or, warp right trailing
edge of stab down and left trailing edge
of stab up. A less-preferred cure is to add
more left rudder.
29* Problem: the model climbs straight or
to the left and does a Dutch Roll; and, when
you try to correct this by using a sidearm
throw, the glider now banks sharply to the
right and goes into a shallow banked climb.
The glider seems to alternate between the
two extremes. Cure: fin is too small. Possibly,
the glider has too much dihedral.
30* If the glider goes up in a proper spiral,
then falls off at the top and stalls: difficult
solution, but initially try a tweak more
right tab at the bottom of the fin (ZWIEBOX)
or a smidge more "down" on the
left side of the stab.
31* If the glider does everything almost
perfectly, but spins to earth at the slightest
upset: maybe the CG is too far aft, but more
likely the left wing panel washin is too
shallow.
32* If the model pulls out of the initial
right bank, goes vertical, and tends to barrel
roll to the left and possibly runs out of
oomph upside down, then tweak a little "down"
into the right side of the stab.
33* The following trim scheme is from the
CHALLENGER article and could be used as a
starting point. It should produce a launch
pattern almost vertical in attitude, with
a slight turn, maximum altitude, and a flick-out
transition on top. Before flying, set up
the model as follows: Bend the fin to the
left slightly (Just bend the surface by squeezing
the wood slightly between your thumb and
finger, compressing the wood on the inside
of the bend while stretching the wood on
the outside. Bend the left side of the stab
(rear) slightly down. Bend the right side
of the stab up slightly more than the left
side was bent down. The ZWEIBOX also uses
this stab tweaking up/down. This contributes
much to the flick rollout. If the model stalls
in the glide, add a little clay to the nose.
If the model dives (it shouldn't if you bent
the stab up enough), bend the right side
of the stab up a little more. If the model
sweeps over on its back on the launch, there
is too much up on the right side (or not
enough down on the left side). Throw again
and adjust until the model is going almost
straight up. If there is not enough left
rudder, the model will go too much to the
right and have a very wide glide circle.
The model has to go slightly to the right
on launch to get a proper transition. Too
much washin in the left main panel will lift
the wing on launch, making transition difficult
and increasing the glide circle. Keep adjusting
the stab and rudder to control the launch;
add or remove noseweight to control the glide.
A full-power launch is almost vertical at
75-degrees to 80-degrees with slight tilt
to the right, and almost overhand. If it
is launched too near the vertical, it will
come over backwards with usually poor transition.
If the model, on a proper launch, sweeps
back or even loops near the top, this means
too much up-bend; reduce the up-bend on the
right side and/or increase the down-bend
on the left side. If the model comes into
the transition a little shaky, makes a fast
run, and loses a little altitude before settling
into its proper glide, it can usually be
corrected by any or all of these adjustments:
bend the right stab up a very small amount,
decrease the down-bend on the left stab slightly,
remove a small amount from the washin tab,
or reduce the left rudder bend slightly.
34* An alternative trimming scheme is a little
bit of washin in the right inner wing panel,
stab tilt for a left glide, and a bit of
right rudder tab to prevent the model from
spinning in when in a thermal. This technique
is used by Martyn Cowley (GOLDRUSH). Martyn
says that it may sound like a spiral dive
waiting to happen, but that it is great for
trimming the throw part of the climb - just
like a Power model, rolling left while turning
right.
- Thanks Jerry for all the great info on HLG's -
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