Horejsi Long Shot 3 Instruction Manual

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LONG SHOT 3
Building instructions
Dear customer,
You have just became owner of our RC hand launch glider (Discus Launch Glider, DLG) Long Shot 3. It is the new
version of our very successful Long Shot 2. Thank you for your decision.
The model is designed to be launched by the “discus launch” method. The flyer holds the model at the peg located
in the wingtip, between forefinger and middle finger, rotates 360 deg and releases the model. The model will climb
much higher than by the classical “javelin” style launch. Another important advantage is that the joints of your arm
will not suffer pain and injuries are almost unknown
The basic feature of the DLG of this type is the rear position of the centre of the model side area. It is achieved
with the large area of fin and rudder and low wing dihedral. This is the most important feature of the design, so do
not change these elements.
The wing is equipped with a series of airfoils AG 45xx ct designed by Mark Drela. It has very low drag, allowing a
high climb during the launch and rapid cruising while hunting thermals.
The structure makes use of the excellent properties of modern materials. The result is light and very rigid
construction. The weight of the model ready to fly can be as low as about 280 grams. The fuselage is of pod and
boom design. The pod is carbon or carbon/Kevlar shell, carbon reinforced. The boom is made of carbon/glass
composite tapered tube, which is very strong yet light.
Assembly
You will need:
RC transmitter, at least 4 channels, processor controlled and lightweight unit recommended.
Micro receiver, at least 4channels.
Note: the exact minimum numbers of Tx and Rx channels can depend on the type of equipment used. Number of
transmitters need 5 channels receiver to control 2 aileron servos in wing.
4 micro servos (6 to 9 grams). We recommend digital servos for the ailerons.
Power supply: 4 NiMh cells 250 mAh or similar, the weight should be about 30 grams.
CA glue, good Epoxy.
Basic modeling tools.
Fuselage
The fuselage is heavily loaded by centrifugal forces during the launch and must be firm and rigid.
Make up (drill and file out) the aileron servo cable access hole in the wing saddle, with the centre about 30 mm
behind the wing leading edge. This hole serves also as the aileron servo cables exit. The hole must be oval and
as small as possible, about 12 mm wide and 18 mm long. A large rectangular hole would weaken substantially
the pod in this area.
Cut the tube to length, shown on the drawing. We always try for perfect fit, but if the tube has some play
on the pod, you can cut a piece off the front end of tube first, cut the tube to length from the opposite
(thinner) side then.
WARNING: DO NOT GLUE THE BOOM TO THE POD IN THIS STAGE YET!

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Make the slot in the fin 28 mm deep, ca. 8 mm wide – check the width, so that it fits onto the boom end.
Take the rudder and elevator servos. Make up the opening for the servos in the balsa servo floor. Assemble the
floor with the ply cross pieces, drill holes for the servo fastening screws and install the complete tray in place. For
the pod-side walls strength it is important to mount the servos on the servo tray provided. DO NOT omit
the servo tray as it plays important structural role in fuselage resistance against the centrifugal forces
during the launch (the tray serves as the shear web, the fuselage sides are the “spar strips”).
Make the canopy lock of double piano wire 0,8 mm. Bend to shape, the ends meet in the middle of the length of
the lock. CA dip glue the lock wire to the hatch in the middle, spray CA activator. Do not use much CA, as it can
get hot and warm the canopy during the hardening.
Secure with epoxy soaked rectangle of carbon cloth (see the procedure for the wing joiners).
Using a fine file, make small notches in the pod, so that the lock wire can not shift sidewise.
Wing
The foam color can vary according to the producer. Anyway, the material is same.
VERY IMPORTANT WARNING: NEVER touch the wing / stab surface with nitrate base solvent. The skin is
slightly porous and the solvent would definitely damage the foam core!!!
For the same reason do not use common CA glue for the wing / stab assembly.
The wing is supplied in two parts. Mark position of the two mounting screws on the root ribs and make up small
half-round notches with rat-tail file (2 in each panel). Use good 5 minutes Epoxy to glue the wing parts together.
The dihedral of each panel is 6 deg. With one wing panel laying flat on the building board, the second panel is
supported 155 mm at the tip (2x6 deg = 12 deg).
Carefully open the holes to 5 mm dia. The axis of the holes MUST be perpendicular to the horizontal plane of the
model. Install two aluminum tubes, trim to length and epoxy in place. Use drill press and support both part of the
wing equally. Check for correct fit, file out the holes if necessary. Install two aluminum tubes, trim to length and
epoxy in place.
Locate the position of the launching peg: in the left wing tip for right hander and vice versa. Make the hole for the
launch peg.
Make patches from the carbon cloth/adhesive tape according to the pattern (four patches for the wing centre
connection, two round patches for the peg reinforcement. Do NOT try to separate the cloth from the tape in this
stage!!! Soak the carbon with thin slow curing epoxy and lay down over the center/tip connection seam and over
the peg hole, top and bottom. Press with fingers and attach in place with wide adhesive tape all over the patches.
After the epoxy sets, remove all of the adhesive tapes. The surface of the patches is nice and shiny.
Open carefully the 4 mm holes for the mounting screws and the opening for launching carbon peg. Epoxy the peg
well in place.
Note: It is possible that the peg/epoxy joint will loose as it is loaded. When it happens, apply drop of thin CA into
the seam for the good and permanent joint.
Attach the wing on the fuselage with the front screw. Locate and drill hole 3,2 mm dia. for the rear plastic screw in
the pod and run M4 tap. Be sure the wing is square with the fuselage.
Note: Over the years, the 4 carbon wing connection patches proved to give enough strength, provided the model
is flown in F3K style, on a flat field. If you crash, the wing halves usually separate in the middle and the repair is
possible.
If you want to do some slope flying, do not try the hard discuss type launch. The large angle of attack can cause
the wing break. We recommend to reinforce the two carbon patches around the front bolt with doublers of glass
cloth ca. 0,2 mm thick. Any case, be very careful when doing DLG on a slope as it is easy to slip and to suffer
serious body injury.

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Tail
Horizontal stabilizer first:
Screw the stab on the mount. Position the assembly carefully on the boom, so that the stab lower surface is
parallel to the boom upper surface. CA drop in place. When satisfied, use more middle density CA. Or, you can
use epoxy to install the stab. It provides you with some more time for the correct alignment.
BE SURE to drill the mount and to secure the mount on the boom with thread (Kevlar or similar). CA soak.
Vertical stabilizer:
Join the fin and the boom. The fin should be perpendicular to the stab. Secure with epoxy. Be sure the fin is
mounted exactly in the directional axis of the model. Secure the fin with ca 30x25 mm patches of fiberglass (both
sides).
CA in place the horn.
Final assembly
Screw the wing to the fuselage. Push the boom/tail group assembly on the pod and use the thin CA glue NOW,
while checking for correct position of the tail in respect to the wing. Secure the seam with epoxy bead all around.
Drill a hole and install a 1,5 mm carbon peg through.
Install the servos in fuselage. Connect the rudder and elevator horns to the servo arms.
Use the micro pushrods consisting of Teflon tubing and steel inner part. The terminals can be done from Z (servo
arm) and L (horns) - shaped piano wire 0,8 mm, joined to the steel wire with piece of heat shrinking tubing and thin
CA. The pushrods must be run on the outer boom surface and attached at few posts with CA or adhesive tape.
The outlet of the pushrods from the pod is under the wing TE. The stab can be fully detachable. It is also easier to
mount the servos side by side.
Aileron servos:
Check that the servos you are going to use are in good condition, without play. The servo replacement is time-
taking job.
Open carefully the servo cables outlet in the wing bottom center. If necessary, extend the aileron cables. Cut-off
the servo flanges. Run the servo cables through the channels in wing. Push the aileron servos into the openings in
the wing, glue in place with silicone glue and secure with adhesive tape.
Install the horns in the ailerons: The horns must protrude throughout the aileron. Make up epoxy fillets in all four
corners, so that the aileron is “clamped” in between!!!
Connect the horns with servo arms. The link from servo to aileron must be made without any play, otherwise the
ailerons can flutter during the launch.
Recommended method: make the pushrods from 2 mm soft steel of aluminum wire. Bend about 4-5 mm of its end
in right angle and make M2 thread. Run M2 tap into the appropriate hole in the servo arm. Screw the rod directly
into the servo arm. Shorten the rod to appropriate length; make M2 thread and screw the clevis on. This way, the
perfect connection without any play is achieved.
The extension cable between wing exit connector and receiver can consist of 4-wires only, which divide into two
plugs to be pushed into the receiver. For example:
1. + and left aileron servo signal
2. – and right aileron servo signal
A single 4-pole connector is used for the servos to extension lead connection:
1. + both servos
2. – both servos
3. left aileron servo signal
4. right aileron servo signal

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Install the micro receiver and battery. Do NOT insert the aerial into the carbon fuselage, neither run the aerial on
the carbon surface as the control range can be seriously decreased!
Check for the CG position. It should be about 80 mm behind the wing leading edge. A piece of plasticine can be
inserted into the fuselage nose to shift the CG into correct position.
Control movements
The model is normally equipped with 4 servos: two for ailerons, one for stabilizer, one for rudder.
Ailerons - direction control
(measured from neutral aileron position)
12 mm up, 6 mm down
brakes: 30 mm down
flaps: 3 mm down
brakes and flaps should be compensated for with appropriate elevator movements: down elevator for down
ailerons.
Elevator
up/down 10 mm
Rudder
left/right 15 mm, coupled with ailerons
Note: If the wing airbrakes deploy down (as mentioned above) be sure to install the rudder servo. The model can
not be directionally controlled with ailerons when they are deployed f down.
These movements can vary according to your personal preference.
Flying
Generally:
Discus launching is not likely to harm your body in any way, but it is sensible to warm up your muscles
before trying to launch at full power. If you suddenly strain your muscles when they are still stiff from
driving for several hours, or if you work in an office and don't get much exercise, then it is advisable to
treat your joints and muscles with care.
Waving your arms about is not going to help much. The best method is probably to jog up and down the
field for a few minutes, gradually building up speed. (You don't often see modelers doing this on my flying
field.) A more appealing alternative is to launch about ten times, starting very softly, then gradually
building up to almost full power by the tenth launch. In this way your muscles will become warmer and at
the same time, you will have had sensible and useful launching practice.
In the first attempts, test glide by “ordinary” overhead launch and make the necessary trim changes. Then try to
launch with more force, still in the “javelin” style. When satisfied, try the first discus launches.
Start with full 360 deg circle, slowly and smoothly from the very beginning. It is important to do always the same
sequence of footsteps. Draw the model from your back and twist your body from this position. Release with slight
nose up.
Apply full down elevator on the top to bring the model into the level flight.
Increase very slowly the launch velocity. You will be surprised, how easily you can get really reasonable height.
Usual mistakes:
Very important: Keep you arm straight all the way, especially in the release stage. Avoid any tendency to “throw”
the model. Surprisingly, it is nor quite easy.

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Use your body as a “torsion spring”: Draw the model from behind of your back. Unwind before the launch and in
the last launch phase twist the body and move your arm.
Move the CG and trim the elevator, so that the model climbs mildly. Play also with the CG position so that the
amount of the inherent stability suits your flying style: these models fly at low heights and often must cope with lots
of turbulent air. Larger amount of longitudinal stability provided by more forward CG position can be of advantage.
The wing flaps are in neutral position for launch and fast flights while hunting for thermals and for rapid returns
from downwind distances.
The ”neutral position” is with flat wing surface bottom.
For the low sinking rate deploy the flaps about 3 mm down (measured in the wing centre). Deploy the flaps about
40 deg down for escape from height and landing. The directional control with fully deployed flaps should be done
with rudder rather than with ailerons. The model with flaps full down slows down. When moved rapidly back to the
neutral position, the model can stall because the velocity is too low for the wing in this configuration.
Important notes:
•NEVER launch model if there are persons in front of you!!! Remember, the velocity of the model can be close
to 150 km/hour
•If released too early, the model can fly low over the ground, to the right side (right hander). BE ALWAYS SURE
there are no persons in this segment!!!
•Secure the receiver crystal in place with adhesive tape. Otherwise, it can slip out of the socket due the launch
acceleration!!!
•Do not launch model in weeds taller than about knee-height. You would easily damage the outer wing tip.
•Before the first flying, make the test range of the RC set. The carbon used for the fuselage can influence the
signal reception. If you do not have the 2,4 GHz set, the “old fashioned” antenna between receiver and fin tip
still works best.
For the assembly pictures see www.horejsi.cz
The video sequence showing launch of one of the best German flyers, Alex Wunschheim, can be downloaded
from the same site. With kind permission of Alex.
Have a joy with your new LONG SHOT 3!
Horejsi model Ltd.
Czech Republic