Align Trex SE Setup Guide. version 1.0

Although I have successfully flown nitro and electric helis in the past I only recently discovered that my setups were never actually correct. The difference in performance of a correctly configured heli and what I thought was correct is really amazing. This is not a complete build but information on how to correctly setup your servos, linkage, pitch and throttle curve so you have a smooth operating heli.

The following steps are based on a Trex SE that has been correctly assembled and all components installed. The radio used is the Spektrum DX6. These steps are specific to the Spektrum DX6 so please see your manufacturers instructions for placing your radio into the correct helicopter mode, in this case CCPM, and other options such as servo reversing, gyro gain, etc. Radio settings, rates, degrees and any measurements shown in this guide are from my working SE. Do not assume that by using the same values you will get the same results. Please verify all your settings and general operation of your heli. I will always try to keep this information updated and error free however it is your responsibility to make sure your heli is operating correctly.

#1 Radio Setup (Spektrum DX6)

• First we will set the radio into Heli Mode.
  • While pressing up on the scroll and increase buttons, turn the power switch on. You are now in System Mode.
  • Press scroll until TYP is displayed.
  • Press increase and select HE.
  • Press scroll until GER is displayed.
  • Press increase and select A
  • To save either turn the radio off or press scroll and increase at the same time.
• Now we will set options in Function Mode.
  • Turn the radio on if it is not already on.
  • Press scroll and increase. You are now in function mode.
  • The servo reversing menu (REV.NORM) should be visible. If not press scroll until it is.
  • Once you reach the reversing menu, use the channel key to scroll through each channel and set them to the following.
    • AIL=REV
    • ELE=NORM
    • RUD=NORM
    • GER=NORM
    • PIT=NORM
    • THR=NORM
  • Press scroll until TRV ADJ. is visible.
  • Press scroll and select the GER channel.
  • Place the Aileron DR switch to 0. Use the decrease button to set +45%.
  • Press scroll until HLD is visible.
  • Use decrease and set to -1%.
  • Press scroll until you reach the Pitch Curve Menu. Use the channel button to select PLN, P2N and PHN and set the following values using increase and decrease.
    • PLN=35%
    • P2N=50%
    • PHN=100%
  • Press scroll to advance to the next Pitch Curve Menu. Use the channel button select PLS, P2S and PHS and set the following values using increase and decrease.
    • PLS=0%
    • P2S=50%
    • PHS=100%
  • Press scroll to advance to the next Pitch Curve Menu. Use the channel button select PLH, P2H and PHH and set the following values using increase and decrease.
    • PLH=0%
    • P2H=50%
    • PHH=100%
  • Press scroll to advance to the Throttle Curve Menu. Use the channel button select TLN, T2N and THN and set the following values using increase and decrease.
    • TLN=0%
    • T2N=65%
    • THN=100%
  • Press scroll to advance to the Throttel Curve Menu. Use the channel button select TLS, T2S and THS and set the following values using increase and decrease.
    • TLS=100%
    • T2S=80%
    • THS=100%
  • Press scroll until your reach the CCPM Menu. "mix CCP OF" is displayed.
  • Press increase to enable CCPM. Display will change from CCP OF to CP2.
  • Use the channel button to select CP2, CP3 and CP6. All three should have a value of 60% by default. Use increase and decrease to set the following values.
    • CP2 = 55% (Approximately 6 degrees of total cyclic travel [ -, + 3 degrees left and right] )
    • CP3 = 55% (Approximately 6 degrees of total cyclic travel [ -, + 3 degrees forward and aft] )
    • CP6 = 60%
      • CP2 and CP3 adjusts the cyclic travel of your swashplate (forward, back, left, right)
      • CP6 adjust the total up and down travel of the swashplate (pitch of rotor blades)
        • CP2 and CP3 can be increased if you are experienced or after you become comfortable with your heli. The transmitters default setting of 60% will give you about 12 degrees total cyclic travel, [ -, + 6 degrees]. At this high setting the mechanics are very near binding. In addition using that much cyclic may cause bogging. Shoot for 6 degrees total and then advance to around 9 degrees total.

The radio settings should now be very close to final with the exception of possible servo reversing, subtrims and gyro gain adjustments.

#2 Servo mounting, connections, direction and centering

Servo mounting may vary slightly but I found the following offers good alignment. Servo connections shown are for the DX6.

Figure A

Note Ch. 6 servo is mounted from the inside and Ch. 3 is mounted from the outside of the left frame with the servo horn inside the frame halves.

Figure B

Ch. 2 is mounted from the inside of the right frame.

Figure C

• Servo Centering and Direction can now be checked.
  • Remove all servo arms from the servos.
  • Set Aileron D/R Switch to 1.
  • Turn on the transmitter.
  • Make sure all of your trims are at 0.
  • Set your collective (left stick) to center. It should be in the same position as the right stick.
  • Disconnect your motor from the Electronic Speed Control (ESC) and plug a fully charged battery pack into the ESC. Leave the helicopter stationary until the Gyro initiates.
  • Begin putting the servo arms on each of the servos, lining the arm up as close to center as possible. See Figure A, B and C above for arm orientation. It is not necessary to hook up the linkage at this time. Do not worry if they do not line up exactly. We will make adjustments later by using subtrim. If you find a control horn is very far off from center try a different control horn.
  • Now we can check servo direction.
    • Move your right stick (cyclic) to the right. Channel 2 servo arm should move down and Channel 6 servo arm should move up.
      • If this is not the case you will need to reverse one or both of the servos depending on what reaction occurred.
    • Move the right stick (cyclic) forward. The Channel 3 servo arm should move up while the Channel 6 and 2 servo arms move down. The opposite applies when the right stick is pulled back.
      • If this is not the case you will need reverse the Channel 3 servo.
    • Move the left stick (rudder) to the left. The Ch. 4 servo arm should move towards the tail of the heli.
      • If this is not the case then you will need to reverse this servo.
    • Move the left stick (throttle) up and down. Ch 2, 3 and 6 should move together in direction relation to the stick movement.
  • If any servo reversing was necessary, you may have to check for servo arm alignment again to make sure they are as close to center as possible.
  • We will now adjust the subtrim to center any servo arms that need centering.
    • Turn the transmitter on if it is not already on.
    • Make sure both sticks are in the center position.
    • Push scroll and Increase at the same time to enter Function Mode.
    • Press scroll until you reach the SB-TRIM Menu.
    • Use the channel key to select each channel that needs adjusting.
    • Use the increase and decrease buttons to center the servo arms.
      • If subtim value required to center the servo is more than +/- 20 to 30 you should locate a servo arm that will line up closer to center than the current arm being used.
    • To save the information press scroll and increase at the same time or turn off the transmitter
  • After adjusting the subtrims and with both sticks at center, you can now hook up your linkage rods. Linkage rods set to the length specified in the manual will be very close. Choose the same hole in each servo arm that will result in the arm and control rod being perpendicular as shown on Figure A, B and C above, represented by the red lines.

#3 Linkage adjustment , control alignment and pitch

• Now its time to adjust the linkage on the head assembly. In order to correctly set up your new Trex you will need a pitch guage. This tool is used to measure the pitch angle of the main rotor blades in relation to the flybar. The Align Pitch Guage (figure D) works very well and is specifically for smaller electric helis. If you do not have a pitch guage you should not continue until you do or have some other manner of determining the pitch.

Figure D

• Turn on the transmitter.
• Aileron D/R switch to one and all other switches at 0.
• Motor disconnnected for safety.
• Connect battery to ESC and wait for Gyro to initialize.
• All servo arms should still be centered.
• Extend your main blades and make sure the flybar and the blades are level.
• Examine the image below and compare to your head linkage.
• Starting with the linkage coming from the servos, make sure the bottom of the swashplate is level all the way around.
• Move up to the head linkage and adjust as necessary to get the alignment shown below.

Figure E Figure G

• Setting 0 pitch
• Check that transmitter sticks are at center.
• Set your pitch guage to 0 and place it on one of the main blades.
• Hold the flybar and blades level by lifting on the guage.
• If all is well your flybar and top of guage will be parallel showing your pitch is at 0.
• Do the same for the other blade.
• You should be right on if not, very close. You can make slight adjustments using the short linkage connected to the blade grips.

Figure H

• Now we can set your positive.
  • Set your pitch guage to +10
  • Place it on one of the main blades.
  • Push the collective (left stick) all the way up.
  • Level the blades and flybar by lifting on the guage.
  • The top of the guage and flybar should be parallel or very close. (figure I below)
  • If more pitch is needed to get +10 degrees we will need to access the Function Mode on the transmitter.
    • With the transmitter already on, press scroll and increase at the same time.
    • Press scroll until MIX CP2 is displayed.
    • Press channel until MIX CP6 is displayed.
    • Use increase to add more collective. You should see the collective increase as you make the adjustment. Increase until +10 is obtained.
      • Check clearance A between the top of the washout base and bottom of the main rotor housing (figure J below). The gap can be tighter than what is shown but they surfaces should not be butted together.
        • If you are unable to reach +10 degrees before the surfaces touch, there is a problem with linkage elsewhere. Go back and recheck your linkage.

Figure I Figure J

• Now we check the negative pitch.
• Set your pitch guage to -10
• Place it on one of the main blades.
• Pull the collective (left stick) all the way down.
• Level the blades and flybar by lifting on the guage.
• The top of the guage and flybar should be parallel or very close. (figure K below).
  • Check clearance B between the top of the collar and bottom of the swashplate (figure L below).
    • If you are unable to reach -10 degrees before the surfaces touch, there is a problem with linkage elsewhere. Go back and recheck your linkage.

Figure K Figure L

#4 Setting up the tail rotor, tail rotor servo and gyro

• Tail servo setup
  • Turn the radio on if not already on.
  • Set the Aileron D/R Switch to 0.
  • The servo should be centered from the previous steps. If it is not you need to go back to the centering section and do this servo again. (You need to be in flight mode 1.)
  • With the servo centered, horn on, linkage connected, loosen the servo mount bracket so it can be moved on the boom. Position the servo so the tail rotor blade pitch is 0 with the servo arm centered as shown (figure M).
  • Also the bracket needs to be rotated until the control arm runs parallel with the boom. (figure N)
  • Tighten the bracket down once these items are aligned.

Figure M Figure N

• Verify Gyro Direction
  • Examine the diagram below and follow these instructions
    • Hold the heli up at the main rotor button with your right hand. (figure O)
    • Use your left hand to push the tail away from you.
    • Watch the servo and note the direction it moves when you push the tail. The servo horn should move towards the tail as in the diagram.
    • Pulling the tail towards you should result in the servo moving towards the front.
    • If you find that the movement is opposite of what is shown here simply switch the rev/norm switch on the gyro.

Figure O

• Setting Tail Rotor Servo Travel
  • Use the rudder stick (left stick) and give full left rudder.
  • Listen for binding and check clearance. (figure P)
  • If you hear binding or see that there is zero clearance, reduce the gyro travel limit on the gyro until you have some clearance.
  • Do the same for full right rudder to be sure.

Figure P

#5 Verify throttle operation

• Your ESC should be plugged into channel 1.
• Although the ESC may have safety measures to guard against accidental motor starts you should always be cautious.
• Verify that all switches are set to 0.
• Hook up your motor leads to the ESC.
• Turn on your transmitter and set the collective/throttle (left stick) at full low.
• Connect a fully charged battery to your ESC.
• Allow the heli to sit still while everything initializes. You will hear a series of beeps and the motor may bump slightly during the beeps.
• After everything has initialized you may slowly increase collective/throttle (left stick) at which time the rotors should start to turn. (clockwise looking from top).
  • If you hear the motor turning but the rotor does not, reduce collective to full low.
    • The motor may be reversed so swap any two motor leads to reverse operation.
  • Increase collective again and the rotor should turn in the clockwise direction.
    • If the rotor fails to turn again and you hear the motor there are a couple things that should be checked.
      • Hold the main rotor with one hand and attempt to turn the main gear clockwise. It should not turn in this direction however it will turn counter clockwise.
        • If the gear turns in both directions it could be a bad one way bearing or your, a missing or sheared main gear bolt or metal main housing bolt.
          • If the above checks out then your pinion gear is either loose or not making contact with the main gear.

#6 Final Check

• Before attempting hover or flight there are several areas to check and are not limited to the following.
  • Binding
    • Disconnect your motor leads for safety
    • Give the heli full cyclic by moving the cyclic (right stick to the top right corner).
    • Spin the blades with your hand and watch and listen for any binding or rubbing.
      • TIP: watch the swashplate and if it moves or appears to bump then something is probably hitting somewhere.
    • Continue doing this on the remaining three corners of the cyclic control (full top left, bottom left, bottom right). The corners should be the full extent of motion but to be safe check the entire range by moving the cyclic stick in a complete circle, or in the case of the DX6 a square.
  • Clearance
    • Move all servos to their fullest extent in both directions.
      • Make sure servo arms do not touch, rub or extend into any moving part like the main gear.
  • Gear Mesh (the amount of play between the main and pinion gear)
    • Finding the right gear mesh is very important. Although the gear appears round, it will likely be slightly oval (egg shaped) having one or more high spots. Due to this it will be necessary to have a tight mesh on the high sides of the gear in order to get correct mesh on the low. If you were lucky enough to get a truly round gear then you can have correct mesh all the way around. Clone that gear and send it to me.
      • Unfortunately its really not possible to visually verify mesh while the gears are on the heli so we use our thumb to rock the gear and feel the mesh. Look at the images below to see what you are feeling for.

• If you get the mesh at the high side to where there is no gap, then your low side mesh should be correct. If its not then your gear is seriously out of round and probably not suitable to use. A gap as in the last image will result in a stripped gear.

**NOTES**

• Flight Mode Switch
  • Switch at 0 = pitch settings of -3, 0, +10 and throttle curve of 0, 60, 100.
  • Swithc at 1 = pitch settings of -10, 0, +10 and throttle curve of 100, 80, 100.
• Throttle Hold Switch
  • Switch at 0 = Normal operation
  • Switch at 1 = No motor operation
• Aileron D/R Switch
  • Switch at 0 = Gyro Head Hold Mode ON ( should remain in this mode)
  • Switch at 1 = Gyro Head Hold Mode OFF
• Elevator D/R Switch
  • Factory default on both 0 and 1
• Dual rate settings should be at factory default unless you made changes outside these instructions. Its always better to double check.
• Radio settings, rates, degrees and any measurements shown in this guide are from my working SE. Do not assume that by using the same values you will get the same results. Please verify all your settings and general operation of you heli.

Coming Soon:

Actual Size Printable PDF to easily set your linkage lengths. This is image is a sample.. DO NOT USE.

All images Copyright 2006 Sean Smith

History

01/25/06 - updated CP section of radio setup to better explain the function of CP2, CP3 and CP6. Added gear mesh information. Added image for tail rotor slider gap.