SIG SIGRC76EGARFG Assembly Manual Download Page 4

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(4)   Nylon Pushrod Keepers; for ail(2), ele(1), rud(1)

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(1)   Pushrod Connector w/Set Screw, for throttle

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(1)   Small Balsa Block; for glow throttle pushrod

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(2)   7-1/8" long Wire Pushrods, threaded on one end, 

          with M2 Hex Nuts(2); for ailerons

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(2)   28" long Wire Pushrods, threaded on one end, 

          with M2 Hex Nuts(2); for elevator & rudder

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(1)   19-1/2" long Wire Pushrod, with Z-bend; for throttle

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(1)   14" long Nylon Pushrod Tube, for throttle

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(1)   Pilot

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(1)   2-1/4" dia. Spinner

Your Somethin’ Xtra ARF is covered with ORACOVER®, a pre-
mium quality covering made in Germany, and sold in the U.S. by
Hanger-9 as Ultracote®.

Colors Used On Your Airplane

ORACOVER® #10 White (Ultracote® #HANU870 White)

ORACOVER® #71 Black (Ultracote® #HANU874 Black)

ORACOVER® #23 Ferrari Red (Ultracote® #HANU866 True Red)

or

ORACOVER® #10 White (Ultracote® #HANU870 White)

ORACOVER® #71 Black (Ultracote® #HANU874 Black)

ORACOVER® #43 May Green (Ultracote® #HANU903 Apple Green)

If  sometime  in  the  future  you  need  replacement  covering  or
matching paint for repairs, they are available from your local hobby
dealer or online from Hanger-9.

How To Tighten Loose Covering

After you open your Somethin’ Xtra and take all the covered parts
out of their plastic bags, the covering may begin to wrinkle.  This
is not unusual and is no cause for alarm.  Your airplane was built
and covered in a part of the world which has relatively high hu-
midity and therefore, the wood was likely carrying a fair amount
of moisture.  When exposed to drier air, the wood typically loses
this moisture, dimensionally "shrinking" in the process.  In turn,
this may cause some wrinkles.  However, wrinkles are easy to re-
move by just using a hobby type heat iron.  

Caution: Trying to remove the wrinkles by hastily going over them
with a heat gun can lead to more problems.  You should take your
time to carefully go over the entire model with a covering iron, as
we will describe.

We suggest  using a model airplane covering iron for this process.
Cover the iron's shoe with a thin cotton cloth, such as an old t-
shirt, to prevent scratching the covering as you work.

After covering your iron, the next step is to set the iron to the cor-
rect temperature.  This is critical for achieving a good result!    The

iron should be set to about 

220

O

F - 250

O

F (104

O

C - 121

O

C)

as

measured on the bottom of the iron using a thermometer.  

If you do not have a thermometer, you can find the correct tem-
perature by trial and error.  Set your iron to a medium setting.
Glide the iron over some of the covering that is over solid wood,
such as the sheeted wing center section.  Observe the covering
to see if any bubbles appear.  If bubbles appear, the covering is
getting too hot!  Turn down the temperature and repeat the test.

If no bubbles appear, turn up the heat slightly and repeat the test.
Keep adjusting until you “zero in” on the correct temperature.  Find
the temperature that will get the covering to stick down without
forming bubbles or causing the seams to pull away.  

Once your iron is set to the correct temperature, go over the entire
framework of the airplane, making sure that the covering is se-
curely bonded to the structure everywhere the covering comes in
contact with the wood underneath.  This takes some time, but is
worth the effort.

After you have all the covering secured onto the solid areas, turn
the temperature of the iron up to approximately 

300

O

F - 320

O

F

(149

O

C - 160

O

C)

.  This is the correct temperature for shrinking the

covering material.

Use the iron to tighten up any wrinkles in the “open” areas of the
model (no wood underneath the covering).  Glide the iron over the
wrinkle for a few seconds, then remove.  Repeat until the covering
is tight with no wrinkles.

If wrinkles keep coming back on the tail surfaces, you may need
to “ventilate” the areas between the ribs.  Otherwise the air that is
sealed in those relatively small areas will expand when the heat
is applied and actually cause the covering to stretch instead of
shrink.  Use a pin to poke a tiny hole in the covering between each
rib, on the bottom of the part.  That will let the expanding air es-
cape and the covering to shrink properly.

Caution When Using Heat Guns: You can also use a hobby-type
heat gun to shrink the covering, but you must be careful around
seams or color joints.  Getting too much heat on the seams may
cause them to "creep" or come loose.  You must also be careful
when using a heat gun when working around the windshield and
side windows - heat will distort the clear plastic material.

Recommended Temperatures:

To adhere the covering - 220

O

F - 250

O

F (104

O

C - 121

O

C) 

To shrink the covering  - 300

O

F - 320

O

F (149

O

C - 160

O

C)

NOTE: 

In this manual, any references to right or left, refer to your

right or left as if you were seated in the cockpit of the airplane. 

Also, some of the photos in this manual may show a Somethin’
Xtra with a different color scheme.  The steps are still the same.

4

COVERING MATERIAL

Summary of Contents for SIGRC76EGARFG

Page 1: ...ea 725 sq in 46 7 dm2 Length 48 25 in 1226 mm Flying Weight 5 5 5 lbs 2268 2495 g Wing Loading 16 17 6 oz sq ft 48 53 g dm2 Radio Required 4 Channel with 5 Standard Servos Glow 4 Channel with 4 Standard Servos Electric Glow Power 2 Stroke 40 46 cu in 6 5 7 5 cc 4 Stroke 53 65 cu in 8 6 10 7 cc Electric Power 700 1000 watt Brushless Motor 550 800 kv 75A Speed Control ESC 4S 6S 3000 4000 mAh Lipo Ba...

Page 2: ... engines for the Somethin Xtra 2 STROKE 40 to 46 cu in 4 STROKE 53 to 65 cu in Whatever brand engine you choose take the time to carefully break it in according to the manufacturer s instructions A good running reliable engine is a minimum requirement for the enjoy ment of this or any R C model aircraft PROPELLER FOR GLOW Refer to the engine manufacturer s instructions for recommenda tions on prop...

Page 3: ...cludes the capability of balancing the available voltage in the cells en suring that the battery pack is at peak capacity at the end of the charge cycle This translates to better flight times and a longer life from the battery pack REQUIRED TOOLS For proper assembly we suggest you have the following tools and materials available A selection of glues SIG Thin Medium Thick CA Glue CA Accelerator CA ...

Page 4: ...r you can find the correct tem perature by trial and error Set your iron to a medium setting Glide the iron over some of the covering that is over solid wood such as the sheeted wing center section Observe the covering to see if any bubbles appear If bubbles appear the covering is getting too hot Turn down the temperature and repeat the test If no bubbles appear turn up the heat slightly and repea...

Page 5: ... get it to fall through the openings in the ribs until it emerges at the end rib Once you ve got the plug to the end rib direct it through the round hole in the bottom surface of the wing panel By that time the servo itself should be next to the servo mount cutout and ready for mounting f Fit the servo into the servo mount in the wing panel note that the servo is positioned so that the servo arm i...

Page 6: ...leron Pushrod Wire all the way up to the end of the threads Then screw the metal clevis halfway onto the threaded end of the Aileron Pushrod Wire b Clip the metal clevis into the last hole in the nylon control horn Lay the other end of the pushrod wire over the outer hole in the servo arm Use a felt tip pen to mark the wire where it crosses the hole Use a pair of pliers to put a sharp 90 degree be...

Page 7: ...ng three M4 x 20mm Socket Head Bolts and three M4 Flat Washers bolt the landing gear onto the fuselage TAIL SURFACE INSTALLATION For the following steps you will need 1 Fuselage 1 Wing 1 Stabilizer Elevator set 1 Vertical Fin Rudder Set 2 M6 5 Nylon Wing Bolts 1 Tailwheel assembly including Wheel and Wheel Collars 2 M3 x 15mm Screws 1 Nylon Rudder Steering Clasp with Bolt and Hex Nut 2 Nylon Contr...

Page 8: ... fin and the rear of the fuselage using the same techniques you did for the other hinges refer to page 5 of this manual Make sure to line up the top of the rudder flush with the top of the fin This will ensure the tail wheel bracket lines up correctly Let the hinges dry adequately before proceeding 18 Look closely and you will find three holes pre drilled near the bottom of the rudder for mounting...

Page 9: ... where it crosses over the outer hole in the servo arm d At the tail end unlock the elevator from neutral position and then unclip the clevis from the control horn Remove the clevis and the hex nut completely off of the pushrod and set them aside Now pull the pushrod out of the fuselage from the servo end It will be easier to complete the next three steps with the pushrod out of the airplane e Cut...

Page 10: ... the previous step 26 from 4 25 The result is the dis tance you need to set the front of the firewall from the back edge of the plywood motor mount box With the motor we are using in these photos the motor measurement is 2 77 So 4 25 minus 2 77 1 48 Your result may be different depending on your motor b Carefully measure and mark the distance determined in the previous step from the back side of t...

Page 11: ...of swapping two of the motor wires 31 Next bolt the motor mount box on to the front of the airplane using the M4 x 20mm Socket Head Bolts and Flat Washers pro vided NOTE The best tool for this job is a hex ball driver not fur nished With the hex ball driver you can easily access the top two bolts over the top of the front firewall And you may be able to access the bottom two bolts by going through...

Page 12: ...ing and make any adjust ments needed to get it back in position d Now drill another pilot hole for the upper screw on the other side of the cowling Install the screw e Repeat this process to install the two bottom cowl mounting screws Remove all the tape COOLING IS VERY IMPORTANT 35 With a fully cowled motor it is very important to make sure your motor is getting properly cooled Air must be able t...

Page 13: ...be the most trouble free installation in the Somethin Extra 37 Bolt the two Nylon Engine Mounts on the front of the fire wall using M4 x 25mm Bolts and M4 Flat Washers provided 38 Set your engine in place on the beams of the engine mounts Slide the engine forward or aft on the engine mounts until the front of the engine s thrust washer is 4 1 4 from the front of the firewall Double check to make s...

Page 14: ...he fuselage side Glue the block to both the sleeve and pushrod side THROTTLE PUSHROD FOR 4 STROKE ENGINES 4 stroke glow engines typically have their carburetor on the back of the engine This puts the throttle arm very close to the firewall of the airplane makng the hookup of this end of the throttle pushrod more difficult If you are using a 4 stroke engine you should take a look at some of the spe...

Page 15: ... the fuel tank and the wing joiner tube 50 Mount the receiver on off switch in the fuselage side No tice that there is a cutout for the switch in either side of the fuse lage Remove the covering over the cutout you want to use rhwn bolt the switch in the cutout 51 Mount your propeller on your motor The installation of your glow engine system is complete INSTALL PILOT CANOPY Both glow engine and el...

Page 16: ...time we would urge you to seek the assistance of a qualified R C pilot to help you through the first few test flights Keep the ailerons and eleva tors in their low rates Once airborne get to a reasonable altitude before inputting any trim changes Once the model is trimmed for straight and level flight begin getting the feel for the way it flies We hope that your Somethin Xtra will provide you with...

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