Bergen INTREPID GAS User manual
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There are two more adjustments to make on your new Intrepid. These are the tail
rotor and the throttle. With the radio turned on and the tail rotor in neutral (if you have tail
compensation turned on, make sure that the collective is also in neutral), position the tail
rotor servo arm one spline ahead of the position that would have the ball vertically
positioned. Now connect the pushrod to the servo, and adjust it’s length so that there is
approximately 5 to 10 degrees of positive pitch in the tail rotor. (“Positive” pitch in the tail
rotor is in the direction so as to make the tail rotor blow air to the right of the helicopter
when it is rotating.) The length of the servo arm should be made such that with full
movement in each direction a very slight binding occurs in the pitch slider on the tail
rotor output shaft. This binding will never occur in flight, as the gyro will decrease the
available movement. The throttle linkage should be set so that at 50% throttle
movement the pushrod is at a 90-degree angle both at the servo arm and at the throttle
lever on the engine. The length of the throttle servo arm should then be made just long
enough to achieve full opening of the carburetor, and full closing of the carburetor with
the throttle trim in it’s lowest position.
ENGINE BREAK-IN
Engine break-in should be done carefully with the proper mix of fuel and oil. Fresh 87
Octane gasoline should be used. Use a high quality full synthetic 2 stroke oil, such as
Yamalube R or Morgan Synthetic oil. Mix 6 oz. Of oil per 1 gallon of gasoline. Use this
mixture ration for the first two gallons. After that, the oil can be reduced to 5 oz. Per
gallon. Adjust the low speed needle on the carburetor (marked L) between 7/8 and 1 turn
from closed. Adjust the high speed needle (marked H) between 1 ¼ and 1 3/8 turn from
closed.
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FINAL ADJUSTMENTS
The two aileron pushrods should be adjusted so that with no control input, the rear-
most balls on the bell cranks are positioned directly over the pivot point for the
transverse lever. This will place the horizontal arms on these bell cranks parallel with the
collective levers. Since these pushrods attach to the servo at an angle from either side,
in order to achieve equal movement on the aileron control, the balls on the aileron servo
arm should have been offset forward, per the drawings.
Now its time to adjust the elevator control system. The pushrod-to-servo adjustment
should be accomplished with the same procedure we used on the collective servo.
When positioning the servo arm on the elevator servo, it should be placed on a spline so
that when the servo is in neutral, the upper elevator bell cranks balls (the unused ones at
this time) are vertical. This will determine the elevator trim. The two pushrods should
then be attached to the rear of this top bell crank, and back to the elevator lever. Each of
these pairs of pushrods should be of equal length (two different lengths, but two
matched pairs). Once these are adjusted to equal length, they should NEVER be
adjusted further.
These are not the linkages to use to mechanically trim the helicopter. If they are not
of equal length, binding will occur at some point in their movement.
One thing to keep in mind here, these two sets of pushrods are NOT
ADJUSTED except to make them equal. The servo arm on the elevator must be
positioned on a spline that will allow the final elevator lever to be parallel to the
main shaft.
Now it is time to adjust the four pushrods that support the swash plate. All four of
these pushrods should be of identical length. These pushrods should be adjusted so as
to give your swash plate equal movement up and down, as the collective lever is moved
to each extreme. If your Intrepid needs any trim adjustments that cannot be
accomplished from the transmitter, these are the pushrods that should be adjusted.
The pushrods that attach the hiller levers (flybar control arms) to the washout levers
should, of course, be of identical length. A “generic” length was given before, and it will
work well. If you are going to maximize every control on your Intrepid for 3D style
aerobatics, you can also shorten these two pushrods slightly (they MUST remain equal
in length). This will allow the washout levers to be slightly higher throughout the
collective range, and allow a small increase in cyclic travel at extreme positive collective.
Now, it’s on the one of the most crucial adjustments on your helicopter, although it’s
one of the easiest to achieve correctly. The bell-hiller mixers that are attached to the
blade holders should be perfectly horizontal in the center of your collective range. If this
is adjusted correctly, your Intrepid will always have the same “feel” when flying, no
matter where the collective is. The bell pushrods (they go from the swash plate to the
bell-hiller mixer), and the hiller pushrods (the short ones from the flybar seesaw to the
mixing arm), should be adjusted so that at “neutral” collective the bell-hiller mixer is
exactly horizontal. What this means is that if you want to have a total pitch range of plus
10 degrees to minus 10 degrees, the bell-hiller mixers should be horizontal at 0 degrees
pitch. If you are a beginner, these mixers should be horizontal at a pitch setting of +5
degrees, with ten degrees being maximum pitch and o degrees being minimum pitch.
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62. Canopy
Bag# Part# Qty Description
- 1921 1 Canopy - Lexan
1 1945 4 Canopy Grommet
1 1946 4 Thumb Screws
If canopy is to be painted on the inside, leave the blue plastic coating on the outside of the
canopy halves until finished painting. This will add protection should any overspray get on the
outside of the canopy.
Prepare canopy halves by washing in warm soapy water to remove grease and finger oils.
Dry completely.
When painting, use a good quality paint that will adhere to the lexan and be fuel proof. One
method is to use lacquer based R/C car body paints, such as Pactra lexan paint on the inside
of the canopy, followed by a fuel proofing coat of polyurethane for protection. A good
suggestion is Top Flite Luster Kote. It will not attack the lacquer color coats. A paint that
remains flexible is preferred, as the lexan can flex quite a bit.
Trim around the outside of the canopy halves with scissors. Lexan scissors for the R/C car
bodies works well. Where the 2 halves come together, leave about ½ inch. In the open areas,
leave about ¼ to 3/8 inch of lexan past the bends that are the edges of the canopy.
Glue the 2 halves together using a good glue that remains flexible, such as Pacer Zap A-
Dap-A Goo II or Shoe Goo. Use clothes pins to hold the halves together in place until
completely dry.
Remove the clothes pins and trim the glued edges to about ¼ inch.
Use some excess lexan to reinforce the areas at the bottom and top of the canopy where the
2 halves separate and open up in the back. This will add strength and resist vibration.
Drill (2) 9/32 inch holes, 2 3/16 inches from the top of the canopy and 1 1/2 inches from the
back edge of the canopy, on each side. These are the top canopy mounting holes. They are
only approximations. Trial fitting to clear all the controls and sideframes is necessary.
Put 2 grommets into the holes. Temporarily mount the canopy on the helicopter, putting the
top canopy standoffs into the grommet holes.
Hold the bottom of the canopy up so that it doesn’t hit the skid or the sideframe and prop it up
with a book.
Using a flashlight, shine the light into the canopy so that the shadows for the lower canopy
standoffs can be seen through the canopy. When satisfied as to the position of the canopy,
mark the position for the hole on each side of the canopy.
Drill (2) 1/16 inch holes in the marked locations. Mount the canopy on the helicopter and
check that the holes line up with the standoffs.
Open the holes to 9/32 inch and insert 2 grommets.
Mount the canopy and check for a final fit. Fasten the canopy using (4) thumb screws.
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CANOPY
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Cut a piece of fuel tubing about 4 3/8” long. Push one end onto the clunk. Push the other end
on the Double End Fitting, on the non-threaded end. This length is approximate, as the final
length may need adjusting slightly to get proper clunk operation.
Insert the Double End Fitting into the center hole in the tank, from the inside. Screw (1) Fuel
Tank Nut on the outside of the tank on the threaded nipple sticking out from the hole. Do not
tighten at this time. This is a trial fit only. This is the fuel pickup side of the tank.
Check for correct clunk operation by tipping the tank in various orientations to make sure the
clunk reached as far as it can, but does not get hung up on the end or sides of the tank.
Adjust the fuel line length as necessary.
Insert the tank into the opening in the lower sideframes from the front of the machine. The
end with the fittings go in first. The fittings should fit up in back of the rear of the radio tray.
Put the lid on the tank and tighten.
Connect a piece of fuel line tubing (medium size, not included) onto the center pickup line of
the tank. Connect the other end of the fuel line to the carburetor fuel inlet furthest away from
the little fuel bulb on the carb.
Connect a piece of fuel tubing (medium size, not included) onto the left-hand side fitting of the
tank. Connect the other end of the fuel line onto the other carburetor fitting (the one next to
the little fuel bulb on the carb. This is the return overflow for the fuel pump in the carb.
Connect a small piece of fuel tubing on the remaining fitting on the tank, and run it down
below the bottom of the lower sideframe. This the overflow vent for the tank.
When fueling the machine, disconnect the fuel line between the center tank fuel outlet and the
carburetor and fuel through the line into the tank. Fill until the fuel almost comes out the top of the
overflow vent of the tank.
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FUEL TANK
61. Fuel Tank
Bag# Part# Qty Description
3 1880 1 Fuel Tank
3 1850 1 Clunk
3 1855 2 Single End Fitting
3 1860 1 Double End Fitting
3 1865 3 Fuel Tank Nuts
3 1870 1 Fuel Tubing
Drill (3) 3/16” holes about 1/2” from the closed end of the tank, all on the same face of the
tank, on the centerline with that face, about 1” apart with the center hole on the centerline of
that face.
Deburr each hole, both on the inside and the outside of the tank.
Insert (1) Single End Fitting in one of the end holes on the inside. A long, skinny hemostat
forceps works good for this. Screw (1) Fuel Tank Nut on the outside of the tank on the
threaded nipple sticking out from the hole. Be sure to get the nut tight to make a good seal.
Repeat with the second end hole.
Fuel Pum
p
Return
Fuel Inle
t
Fuel Tank Pickup
Fuel Return
Overflow Vent
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FINS
60. Fins
Bag# Part# Qty Description
10A 1665 2 Sets Tailboom Clamps
MISC. 5010 2 M3x8 SHCS
MISC. 5050 4 M3x35 SHCS
MISC. 5105 4 M3 Locknuts
5 1832 1 Vertical Fin
5 1835 1 Horizontal Fin
Attach the horizontal fin to the fin clamp that was previously installed onto the tailboom. Use
(2) M3x8 SHCS. The horizontal fin should be perpendicular to the sideframes. Tighten the fin
clamp.
Mount the vertical stabilizer using (2 sets) of tailboom clamps, (4) M3x35 SHCS, and (4) M3
locknuts. Place one of the tailboom clamps just behind the tail gearbox mounting screw, and
one in front of the mounting screw.
Slip the (4) M3x35 SHCS through the 4 holes in the vertical fin and the 2 sets of tailboom
clamps. Attach (4) M3 locknuts to the ends of the screws. Do not tighten yet.
Make sure that the vertical fin is parallel to the sideframes and perpendicular to the horizontal
fin. Now tighten the screws and nuts.
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Adjust the tail rotor blades, so that when looking down on the blades, the top blade points
forward and to the right, indicating proper rudder offset for hover. Set the distance between
the two blades (when looking down at them) at about 20mm. This is the approximate amount
of rudder for hovering.
Make sure that the rudder servo arm is pointing straight down, perpendicular to the tailboom.
Hold the carbon fiber pushrod up in position next to the two pushrod ends. Measure and cut
the carbon pushrod so that it will fit all the way into the pushrod ends with everything
positioned previously.
Mix up some JB Weld Epoxy or use slow cure CA glue to permanently attach the pushrod
ends to the carbon fiber pushrod. Clean the pushrod end and the pushrod with alcohol, dry,
apply the glue and re-assemble to be sure alignment is maintained.
Let cure overnight.
There is a push-pull rudder servo upgrade that completes the push-pull
control system offered by Bergen R/C. It includes a dual ball bearing
supported arm that transfers the servo loads to the arm. Contact your
dealer or Bergen R/C Helicopters for more information.
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RUDDER PUSHROD
59. Rudder Pushrod
Bag# Part# Qty Description
10B 251 1 Push Rod Carbon Fiber
10B 1983 2 Pushrod Ends
10B 1956 2 Ball Link 2.5
10B 5030 2 M3x16 SHCS
10B 5105 2 M3 Locknut
Push (1) M3x16 SHCS through the open end of (1) Pushrod End. Screw (1) M3 Locknut onto
the threaded end sticking out until tight.
Thread (1) ball link onto the threaded end about ¾ of the way on, to allow for adjustment in
both directions.
Repeat with the other pushrod end assembly.
Snap (1) pushrod assembly onto the tail pitch bellcrank.
Snap the other pushrod assembly onto the rudder servo arm ball.
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