Radio setup - Throttle
last updated 11-18-2007

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Step 1: Install the four rubber grommets onto the servo.Next if you are going to use the metal servo mounting plates (PV0054) that come with the R50v2 and R60v2 then do not install the brass eyelets. Otherwise install the brass eyelets through the bottom side. This part is often misunderstood. The flared end of the eyelet needs to be against the mounting surface.
Step 2: Mount the servo in the bottom slot of the servo tray. The top of the servo will be on the left side of the helicopter (the muffler side). And the spline of the servo needs to be on the side closer to the main shaft. Use four of the servo screws that came with the helicopter, not the ones that came with the servo to install it. The servo wire will come from the back of the servo on the right side of the helicopter then go through the hole under the on/off switch and over to the left side of the helicopter. It goes from here to the receiver.
Step 3: Connect the servo wire to the receiver. If you are connecting a Futaba plug to another brand receiver then you will need to remove the keyed edge from the connector. I use some diagonal cutters then use a file to grind the surface clean. Newer Futaba connectors already have two corners slanted as needed on the other brands so just remove the keyed edge then the connector will fit easily in another brands receiver.
The throttle servo plug will connect to one of the first three plugs in the receiver. To know which one consult the chart below. You can confirm you have it in the correct plug by moving the throttle stick and seeing the servo move with it. You will of course need the power to the receiver when you check it. If you do not see the servo move then make sure you have the plug in the correct direction. Also note that if your throttle hold switch is active then you will not get any throttle servo movement.
The channel ordering is:
  Airtronics ===   Futaba ===   JR/Spektrum Radio
1. Elevator === 1. Aileron === 1. Throttle
2. Aileron === 2. Elevator === 2. Aileron
3. Throttle === 3. Throttle === 3. Elevator
4. Rudder === 4. Rudder === 4. Rudder
5. Gyro gain === 5. Gyro gain === 5. Gyro gain
6. Collective pitch === 6. Collective pitch === 6. Collective pitch

Notice how only the first three channels change positions. And that it is the radio that designates the channel ordering, not the receiver. So if you used a JR receiver that has the first plug labeled throttle but your radio was an Airtronics then the first plug is where you plug the elevator servo in.
As a side note, different brand receivers can be used but it is important to use the right crystal and to do a range check. In the above example the radio was Airtroncs and the receiver was JR. If you changed the cyrstal in the receiver then the crystal should also be JR. Also note that not all radios can work with all receivers. A JR radio cannot use a Futaba receiver due to the negative pulse the Futaba uses. However a radio such as the Airtronics RD6000/8000 can be set to work on either positive or negative shift. Also if you have a PCM receiver you can only use the same brand radio. No other brand will work. This is due to copyright laws, each companies PCM code scheme is propietory.

Step 4: Set the throttle trim. This trim control is located to the right of the throttle stick. The position you need to set the throttle trim to depends on if you a mechanical or digital trim. A mechanical trim is one that you physically move, if this is what you have then move the trim all the way to the bottom. A digital trim is just a momentary contact switch that you click up/down one click at a time to position the trim. If this is what you have then center it. Refer to the directions listed below for your radio. Note: radios with digital trim use a throttle cut feature which is either a button or a switch that will be used to stop the engine from running. This function will be setup later in the following directions.
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Airtronics RD6000/8000 - Go to 'Th' then down to 'TRM' and set to 0%.
JR 9303 - Move the throttle trim all the way down.
JR 8103DT (Digital Trim) - watch the bar on the display to center the throttle. The radio will beep on each click but will make a different tone beep when you get to center position.
JR 6102 / 662 - When you press the throttle trim it will display the current value on the display. Set this to 0%.
JR 10X - Move the throttle trim all the way to the bottom.
Futaba 8U-S - Watch the bar on the display to center the throttle. The radio will beep on each click but will make a different tone beep when you get to center position.
Futaba 7C/9C - Watch the bar on the display to center the throttle. The radio will beep on each click but will make a different tone beep when you get to center position.
Spektrum DX7 - Watch the bar on the display to move the trim to the bottom.
Step 5: Center the hovering throttle trim. If your radio has one then it is either a digital control or rotating knob on the top-right of the radio. It is used to adjust the throttle while at center stick hover.
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Airtronics RD6000/8000 - no adjustment needed. Later when you set the throttle curve that will take care of it. All radios should be like this radio is.
JR 9303 - This is a digital trim control to the right of the top-center.
JR 8103 - rotate the knob to the center position, zero.
JR 662 - no control for this function.
JR 6102 - This is a digital trim located to the right of top/center.
JR 10X - The knob is located on the top/front/right. Center this control.
Futaba 6X - The knob is located on the top/front/right to the left of the display. Center this control.
Futaba 8U - The knob is located on the top/front/right. Center this control.
Futaba 9C - The knob is located on the top/front/right. Center this control.
Spektrum DX7 - The digital trim is to the right of the top-center. You will see a bar on the display that will indicate the position of this trim. And you will hear a different tone when you reach center.
Step 6: Zero the sub-trim. This is also called Center in some radios. If you use the sub-trim trick to prevent servo binding when using aileron to throttle and elevator to throttle mixes then you still have to set the sub-trim to zero. After the servo setup is complete then you can set the sub-trim again from this page <throttle mixing>.
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Airtronics RD6000/8000 - go to 'Th' then down to 'CNT' and set it to 0%
JR 9303 - go to [Sub-trim] and use the scroll wheel to select 'THRO'. Press in on the scroll wheel and adjust the value to 0. Press in on the scroll wheel to store the value.
JR 8103 - go to [Sub-trim] and use the ch. button to get to 'THRO' then set to zero.
JR 6102 - go to [SUB TRIM] and press 'select' button to get to 'TH' and set to 0.
JR 662 - go to 'SB-TRIM' then to 'THR' and set to 0.
JR 10X - enter code 15 [SUB TRIM] and press 'cl' under 'THRO' to zero it out.
Futaba 6X - go to 'STRM' then to channel 3 and set to 0.
Futaba 8U - go to 'SUBTRM' then to channel 3 'THR' and set to 0.
Futaba 7C/9C - go to [SUB-TRIM] then to 'CH3:THR' then set to 0.
Spektrum DX7 - go to [SUB TRIM] and press 'select' button to get to 'THRO' and set to 0.
Step 7: Set throttle curve. The throttle curve needs to be set to the default settings otherwise you would never get the correct end points. For an understanding of what a throttle curve is, go <here>.
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Airtronics RD6000/8000 - go to 'Th' then down to 'CU.PH'. Press f.mode button until display shows normal flight mode values 'N:'. Set the value to 100%. Go down one to 'CU.P3' and set to 'INH' (press inc+/dec- at the same time). Go down one to 'CU.P2' and set to 50%. Go down one to 'CU.P1' and set to 'INH'. Go down one to 'CU.PL' and set to 0%.

JR 9303 - go to [THRO CURV]. To the right of [THRO CURV] make sure it has 'N'. If not then flip the flight mode switch so that it does. Under [THRO CURV] make sure this has 'NORM'. If not then highlight it then press down on the scroll wheel and change the selection to 'NORM'. Press the scroll wheel again to exit. Now we need to set the values in the curve. Set Point-L to 15% (this will give you an IN=-15/OUT=0 with the trim all the way down), Set Point - 1 to INH by highlighting it then press in on the scroll wheel and then press the CLEAR button on the left of the radio. Set Point - 2,3,4 all to 50%. Point - 5 - INH and Point H - 100%.

JR 8103 - go to [THRO CURV]. Press 'SEL' button to get to 'NORM' flight mode. Use the '<Ch' or 'Ch>' buttons to select 'L' on the graph and set the value to 0%. Press 'Ch>' to get to '1' to 'Inh' by pressing the 'Clear' button. Press 'Ch>' to get to '2' and set to 50%. Press 'Ch>' to get to '3' to 'Inh' by pressing the 'Clear' button. Press 'Ch>' to get to 'H' and set to 100%.

JR 6102 - go to [THRO]. Press 'SELECT' button to get to the mode selection and set to 'NORM'. Press 'SELECT' button to get to 'LOW' and set to 0. Press 'SELECT' to get to '1' and press 'CLEAR' to set to 'INH'. Press 'SELECT' to get to 'MID' and set to 50%. Press 'SELECT' to get to '3' and press 'CLEAR' to set to 'INH'. Press 'SELECT' to get to 'HIGH' and set to 100%.

JR 662 - go to 'TLN' and set the value to 0%. Press the 'channel' button to get to 'T2N' and set to 50%. Press the 'channel' button to get to 'THN' and set to 100%.

JR 10X - enter code 18 for [THRO CURVE]. When it ask if you want it to hold the servos answer no. Make sure your flight mode switch is in the Normal position (POS-N). Move the throttle stick all the way down (in=0) and set out=0. Move the throttle stick all the way up (in=100) and set out=100. Move the throttle stick to center position (in=50) and set out=50.

Futaba 6X - Setup of the top and bottom points are done by way of the end points. To set the middle point go to 'HV-T' and set to 0%.

Futaba 8U - Go to 'TH-CRV NORM'. Press the right cursor arrow to get to point 1 and set to 0%. Go right to point 2 and set to 25%. Go right to poing 3 and set to 50%. Go right to poing 4 and set to 75%. Go right to poing 5 and set to 100%.

Futaba 7C - Go to [TH-CRV]. Select 'N(N)' flight mode then go to P1 and set to 0%. Go to P2 and set to 25%. Go to P3 and set to 50%. Go to P4 and set to 75%. Go to P5 and set to 100%.

Futaba 9C - Go to [THR-CURV]. Select 'NORM' flight mode then go to point 1 and set to 0%. Go to point 2 and set to 25%. Go to point 3 and set to 50%. Go to point 4 and set to 75%. Go to point 5 and set to 100%.

Spektrum DX7 - go to [THRO CURVE] - NORM. Press 'SELECT' button to get to 'L' and set to 15. Press 'SELECT' to get to '1' and press 'CLEAR' to set to 'INH'. Press 'SELECT' to get to '2' and set to 50%. Press 'SELECT' to get to '3' and press 'CLEAR' to set to 'INH'. Press 'SELECT' to get to 'H' and set to 100%.

Step 8: Set end points to 80% (aka E.Points, EPA, ATV, Travel Adjust). This functions sets how far the servo moves when the throttle stick is all the way up as well as when it is all the way down. To keep the servo speed linear you need to do a good mechanical setup so the end points are within 5% of each other. So end points of 75/102 would not be good as that would be a 27% difference. Also the ideal configuation for the throttle would have the end points both at 80%. This is the optimal position because it uses geometry to effectively make the servo faster. NOTE: If you have a Futaba 8U or 9C (not 9C-Super) and you use the sub-trim trick to prevent servo binding when using aileron to throttle and elevator to throttle mixes then you need to set the end points at 112%.
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Airtronics RD6000/8000 - go to 'Th' then down to 'EPA'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

JR 9303 - go to [TRVL ADJ.] and select 'THRO'. Press in on the scroll wheel then move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%. Press the scroll wheel again to store the values.

JR 8103 - go to [TRVL ADJ.] and use the ch. button to get to 'THRO'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

JR 6102 - go to [TRAVEL ADJ] and select 'THR'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

JR 662 - go to 'TRV ADJ.' then to 'THR'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

JR 10X - enter code 12 for [TRAVEL ADJUST]. Move the throttle stick up and press the 'cl' under 'THRO' to set the value to 80%. Move the stick down and set this value also to 80%.

Futaba 6X - go to 'ATV' then to channel 3. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

Futaba 8U - go to 'ATV-TH' and set both values to 112%.

Futaba 9C(Super) - go to [E.POINT] then to 'CH3:THR'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

Futaba 7C/9C - go to [E.POINT] then to 'CH3:THR'. Move the throttle stick up and set the value to 112%. Move the stick down and also set this value to 112%.

Spektrum DX7 - go to [TRAVEL ADJUST] and select 'THRO'. Move the throttle stick up and set the value to 80%. Move the stick down and also set this value to 80%.

Step 9: Servo reverse setting. In this step we check if the servo is going the right direction and if not then we go to the reverse menu and change the value for the throttle pitch channel. To check the direction pull the throttle stick down while watching the servo spline. It needs to rotate clockwise. If not then use the instruction below to make it right.
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Airtronics RD6000/8000 - go to 'Th' then down to 'REV' and use the 'inc' or 'dec' button to change the setting.
JR 9303 - go to [REV.SW] and use scroll wheel to select 'THRO' then change the value by pressing in on the scroll wheel.
JR 8103 - go to [REV.SW] and use the ch. button to get to ch. 1 'THRO' then change the value.
JR 6102 - go to [REVERSING SW] and select 'THR' and change the value.
JR 662 - go to 'REV' then to 'THR' and change the value.
JR 10X - enter code 11 for [REVERSE SW] and press 1 to change the value.
Futaba 6X - go to 'REV' then to channel 3 and change the value.
Futaba 8U - go to 'REVERS' and select 'THR' then change the value.
Futaba 7C/9C - go to [REVERSE] then to 'CH3:THR' then change the value.
Spektrum DX7 - go to [REVERSING SW] and select 'THRO' ch 1 and change the value
Step 10: Set the throttle arm. The center of travel of the throttle arm should be at a 90 degree angle toward the servo. Note: In the picture on the right you see that due to the angle the picture is taken the throttle arm does not look 90 degree, but it is. To find the center of travel of the throttle arm rotate it as far as it will go clockwise and make a visual note of that location. Now rotate the opposite way and make a visual note of that location. Rotate the arm to the center of these two end points. Note: Some engines have a mark near the barrel that indicates the center position. Now imagine a line drawn from the center of the carburetor barrel to the center of the screw in the throttle servo arm. The throttle arm should be at a 90 degree angle to that. The Raptor helicopter manual says the center should be straight down, but that is not correct. If that throttle arm needs to be moved then make sure you put blue loctite back on the nut/bolt holding the arm on the carburetor barrel. Once you have the location set then mount the ball on the throttle arm. If this arm has two holes then mount the ball in the hole further from the center. Also remember that the shouldered side of the ball will go against the throttle arm.

Step 11: Mount the servo arm. To start with when installing the throttle link the rod should never cross the centerline (line between the pivot points of the servo arm and the throttle arm). The three pictures above show two examples that are good and one that is bad. When the link crosses the centerline the geometry causes differential movement. Meaning that you will get a non linear movement across the full travel.
Move the throttle stick to the center position (remember throttle curve middle point should be at 50%). Now imagine a line drawn from the center of the carburetor barrel to the center of the screw in the throttle servo arm. The servo arm should be mounted at a 90 degree angle to that. The Raptor helicopter manual says the center should be straight down, but that is not correct. If you find that due to the teeth on the servo spline that you cannot mount the arm exactly 90 degrees then rotate it 180 degrees. The teeth in relation to the arms have a slight offset so that by rotating it to the other side now lets the arm align correctly. Note if you have cut off the opposite arm like the servo in the picture above then you may need to get another arm. Do not cut off the extra arms until you find the one that will work for the right geometry. Now that you have the arm mounted to the servo do not forget to install the screw.

Step 12: Link length - Connect the link to the carburetor then move the throttle stick all the way up. Push the link all the way toward the back and check the distance of the center of hole in link to the last hole in the servo arm. Note if the servo arm goes 1)too far 2)not far enough or 3)exactly matches. Now move the throttle stick all the way down and check it again. In the example above you see that one way the arm does not rotate far enough(2) to match the link and the other way is too far(1). This means the link is the wrong length. In the example we would shorten the link and try again. You want to have the length so the test results are equal. Either up/down are both (1) or both (3). NOTE: If you end up with both (2) then you need a longer servo arm. After you get a longer arm go back to step 11.
Step 13: Mount the ball on the servo arm. To find the correct hole in the servo arm to mount the ball move the throttle stick all the way to the top. Next push the link (attached to the carb.) all the way to the back. Now position the front side of the link over the servo arm and see which hole in the arm will align with the center of the hole of the link. This is the hole you need to mount the ball on. If none exactly match the hole then use the closest hole that is further from the center of the servo arm.
Step 14: Finalize the end points (EPA, ATV, travel adjust) - Move the throttle stick all the way up and the throttle arm full counter-clockwise. Adjust the end point value so the ball aligns with the link. Do the same for full down/clockwise. Both values should be with in 5% of each other. If not then adjust the length of the link one turn and set both end points again. Note: If that made it worse then you adjusted the length the wrong direction.
Note: This step is only for radios with digital throttle trims.
Step 15: Set throttle cut - For the radios with throttle cut, start by setting the bottom throttle curve point for normal flight mode to 20%.
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Airtronics RD6000/8000 - go to 'Th' then down to 'CU.PL'. Press f.mode button until display shows normal flight mode values 'N:'. Set the value to 20%.
JR 8103(DT version) - go to [THRO CURV]. Press 'SEL' button to get to 'NORM' flight mode. Use the '<Ch' or 'Ch>' buttons to select 'L' on the graph and set the value to 20%.
JR 6102 - go to [THRO]. Press 'SELECT' button to get to the mode selection and set to 'NORM'. Press 'SELECT' button to get to 'LOW' and set to 20.
JR 662 - go to 'TLN' and set the value to 20%.
JR 10X - This has the old analog trim so you should skip this step.
Futaba 8U - Go to 'TH-CRV NORM'. Press the right cursor arrow to get to point 1 and set to 20%.
Futaba 7C - Go to [TH-CRV]. Select 'N(N)' flight mode then go to P1 and set to 20%.
Futaba 9C - Go to [THR-CURV]. Select 'NORM' flight mode then go to point 1 and set to 20%.
Spektrum DX7 - go to [THRO CURVE] - NORM. Press 'SELECT' button to get to 'L' and set to 20.
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Some radios have to have the throttle cut feature turned on:
JR 6102 - go to [THRO CUT] and if it says 'INHIBIT' then press INCREASE.
Futaba 8U - go to 'TH-CUT' and use the cursor buttons to select 'INH' and set it to 'on/off'. Then use the cursor buttons to get to the next screen to set the switch you want to use.
Futaba 7C - go to [TH-CUT] and set '>INH' at the top to either ON/OFF. Select the switch you want to use for this function. The default is SW>A.
Futaba 9C - go to [THR-CUT] and set the 'MIX' value to either ON/OFF. Select the switch you want to use for this function. The default is SW>H however that is the trainer switch so if you plan on using trainer mode then choose another switch for the throttle cut feature..
Spektrum DX7 - Go to the system menu by holding DOWN and SELECT as you turn the radio on. Go to the [THROTTLE RECOVERY] and set it to active.
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Next take the throttle link off the servo arm and move the throttle stick all the way down. Now pull the link all the way to the front. Hold the throttle cut button/switch and see if the link and ball match up. If not then adjust the throttle cut function so it does match up.
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Airtronics RD6000/8000 - go to 'Th' then down to 'T-CUT' and use the 'inc' or 'dec' button to change the setting.
JR 6102 - go to [THRO CUT] and adjust the value.
Futaba 8U - go to 'TH-CUT' and adjust the left value.
Futaba 7C/9C - go to [THR-CUT] and adjust the RATE value.

Specktrum DX7 - To use the throttle recovery when you stop the helicopter move the throttle trim all the way down until the trim reaches the bottom. Then with one click up the trim will return to idle position.

For info on setting the throttle curve go <here>.
Next setup the <Collective> servo.