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Old Apr 10, 2010, 07:36 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Set Up the 720 for your Tx

If not selected, choose the control tab.

Select Satellite receivers.

With a DX7, you have several options for Use:

2 Gain, 0 Aux
1 Gain, 1 Aux
0 Gain, 2 Aux

I am used to using the Gear Channel switch for switching from Rate to HH mode, so I selected Aux2 Ch for Cyclic Gain.

Auto Trim at Init should be checked. Enable Logs should be checked. Click on Send Setup.

By using this setup, I elected to make all gain adjustments from the PC Software. If you choose 7Ch, 0 Gain, 2 Aux, you can change the gains from your Tx. See the manual for more details.
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Old Apr 10, 2010, 07:41 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Adjust Inputs from Receiver

Tx powered on, 720 connected to PC, Setup software running.

Give your Tx full up elevator.

Adjust the travel adjust on the Tx until the Elevator field contains 100.0%.
Repeat for down elevator.

Continue with Aileron, Rudder, and collective.

Press Send Setup.

At this point, you may want to save your setup file. Form the PC Setup software top menu, select File, then Save Setup. Choose a location on your hard drive and a file name.
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Old Apr 10, 2010, 07:51 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Watch the Gyro Respond

You can watch the gyro read the relative movement. Lift the front end (probably this will be the end with the servo connectors). Watch the Setup software respond.

You have a number of options with respect to Sensor Displays. The options are available from the View top-line menu option.

If the gyro sense direction is not correct, flip directions from the right side of the Control Tab.
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Last edited by Rickn816; Apr 11, 2010 at 05:13 AM.
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Old Apr 10, 2010, 07:54 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Let's Review

The 720 is connected to your PC.

You have saved the setup to the 720, and you save the settings as a file.

The sat receivers are bound to the Tx.

The Tx is correctly adjusted for 100 % readings on the Live Data (top part) of the setup screen.

The 720 shows correct responses when you move it.

Now, it's time to mount the unit in your heli, and connect the servos, Esc, and external BEC power.

If your heli is fuel powered, or the blades are larger than 500 mm, you should use the Power Bus. See the Power Bus manual. My heli is a TRex 500, and I did not use the Power Bus.

My brain is fried. I'll be back in the morning with more.

Rick
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Old Apr 10, 2010, 08:16 PM
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USA, CA, Oakland
Joined Nov 2009
1,332 Posts
Thanks for all the insight Rick on this... I know this may sound funny, but I'm thinking of putting the 720 on my Blade 400. Not so much because I love the B400.. but I am a relative noobie at helis and I would love to experience the programmability that flybarless has to offer.. and carry that through my growth as a heli pilot. Before I spend too much money on the 'common' upgrades, I'm thinking of going this direction. Plus I want to invest in a system I can take on to my next heli.

So... I thought I read somewhere where you put the SK360 on a B400. What head did you use (would any 5mm shaft fbl head work)? and overall.. what are your thoughts? am I way off base?

Thanks in advance!
L
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Old Apr 10, 2010, 08:43 PM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Quote:
Originally Posted by llbr22 View Post
Thanks for all the insight Rick on this... I know this may sound funny, but I'm thinking of putting the 720 on my Blade 400. Not so much because I love the B400.. but I am a relative noobie at helis and I would love to experience the programmability that flybarless has to offer.. and carry that through my growth as a heli pilot. Before I spend too much money on the 'common' upgrades, I'm thinking of going this direction. Plus I want to invest in a system I can take on to my next heli.

So... I thought I read somewhere where you put the SK360 on a B400. What head did you use (would any 5mm shaft fbl head work)? and overall.. what are your thoughts? am I way off base?

Thanks in advance!
L
No. This is possible. You should consider upgrading the servos. In addition, you will need an external BEC. There are several good heads, including the 450 Align head. I have had excellent success with the RJX heads for both the 450 and 500.

Rick
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Old Apr 10, 2010, 10:09 PM
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USA, CA, Oakland
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Cool. Thanks! I've upgraded the servos and I do have a parkbec from dimension. Sounds like Head shopping is the next step.
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Old Apr 11, 2010, 05:34 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Mount the Gyro

If your heli is fuel powered, or the blades are larger than 500 mm, you will use the Power Bus to make the final connections.

Otherwise, find a stable, protected place to mount the gyro in your heli. I recommend the bottom plate as it is generally solid and you can have good access if needed.

There are as many opinions on correct mounting as users. I found the foam tape provided with the 720 worked very well on my TRex 500. If you have a bigger machine, read the manual on the use of the steel plate.

If you put the 720 on the legacy gyro position, you may find that you need that spot when Skookum releases the GPS add-on feature.

The connections are easy enough.
SW-L for the servo on the hel's left (port) side.
SW-R for the servo on the right (starboard) side.
SW-C for the elevator (fore or aft) servo.
Tail for the tail servo.
Attach the ESC to IO-A(T).
You can use IO-B and IO-C for external, BEC power if you wish.
EXT-LED is for an external LED indicator light.

Note: the SK720 is a a 9-channel Rx.

You may want to shorten the servo, ESC, and BEC leads, but leave enough slack so that they do not pull on the gyro when mounted and enough slack so that you can get to the connections without bending the pins on the 720.

I constructed an external LED. The lamp is a Linrose Superbrite LED part B4361K1/5 red/green/amber-tri color. I used a standard-weight servo extension. Do not make the extension too short or too long. Cut off one end of the extension so the cable is the correct length (I had to do this twice before I got it right). Put a male connector on the cut-off end. PUT THE GROUND (dark wire) ON THE CENTER POSITION. A crimping tool will be just about the best $15 you will spend. Trim the three leads on the lamp and insert the wires into the cable end you just finished. The Linrose lamp came with a fresnel lens, which will help visibility. Finish with a piece of heat-shrink tubing to hold it together and leave a little of the heat shring tube extending past the lens to provide a little shade.
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Old Apr 11, 2010, 05:38 AM
RCHN #150
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Lawrenceville, GA
Joined Nov 2007
5,997 Posts
SK720 Modes and Indicator Lights

Now might be a good time to review the manual about the signals you are seeing on the SK720 and external LED.

When you are connected to the PC through your USB connection, the unit gives a slow, green flash.

When you update the firmware, you will see an alternating red/green flash.

Solid red means it is initializing and not ready to fly.

Solid green means it is in flight mode.

Review the manual.
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Old Apr 11, 2010, 05:44 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
One More Check

At this point, you should have the 720 mounted, preferably on the bottom plate of the heli's frame.

All servos are connected.

The ESC and BEC are connected.

The External LED (if you are using one) is connected.

Start the PC Setup software if not running.

Connect the USB connection. The 720 should show a slow, green flash.

Raise the nose of the heli. On the right side of Live Data (top of the window), the elevator indicator should show green. Or, you can set the View to display Pitch or the Level. If you don't get the correct response, flip the axis. This option is on the Control Tab, on the right side. Repeat for aileron and rudder.
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Old Apr 11, 2010, 05:50 AM
RCHN #150
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Lawrenceville, GA
Joined Nov 2007
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Servo Directions

Do not change the servo directions from your Tx. All changes are made from the PC Setup software.

If you made any changes to the gyro sense direction in the last step, did you remember to Send Setup?

Go to the Swashplate Tab. Make sure you have the correct type selected. For most, the first selection 120 Degree eCCPM is correct. The Swash Ring and Piro Comp boxes should be checked.

The Mix % should be 60 or less. If you need to change a direction, click the appropriate Rev box.

Go to the Swash Servos Tab. From this screen, you adjust trim, travel, and direction. If you make any changes, remember to click on Send Setup.

You may need to switch between these tabs until the servos are moving in the correct directions.

If you need to adjust servo movement to set pitch, for example, use the Travel (%) on the Swash Servos tab.

Be sure to Send Setup when you make any changes.
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Old Apr 11, 2010, 06:00 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Tail Setup

You won't believe how easy this is.

Previously, you selected your tail servo.

Before you begin this part, make sure the servo arm is square, and the tail control bar is square. Set up the servo and tail linkage like you would for a legacy tail gyro. When everything is square, there should be a small amount of pitch on the tail rotors which would blow the tail of the heli to the left when viewing from behind.

Open the Tail Servo tab.

Click on Setup Servo with Rudder Stick. When you click on the bar, you will see instructions. You click on the Centre button to start. Move the tail servo with the Tx to the left position. You do not want the servo to bind, so click just before the slider reaches the end-point on the tail rotor shaft. Repeat for the right stop.

Check the motion. If necessary, click the Rev box. Send Setup.


Click Send Setup.
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Old Apr 11, 2010, 06:15 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Bank Selections

I elected to make all gain changes from the PC software rather than the Tx.

I also elected to use the Gear channel to select the tail banks and the Aux 2 channel to select the gain channels.

Hook up the heli to your PC using the USB cable.

Power on the Tx.

Power up the Heli. With the USB cable connected, the motor WILL NOT START (Thanks, Skookum!).

Flip the Gear Switch. Did the bank indicators over Tail 1 and Tail 2 move? If the switch movement is "backwards" for you, you can reverse the position in the Tx. The Tail 2 bank is set up for Rate mode as the default.

Repeat with Aux 2. Do the bank indicators move correctly?

If not, go back to the control tab and see how you have the Radio Input Options selected.
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Old Apr 11, 2010, 06:24 AM
RCHN #150
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Lawrenceville, GA
Joined Nov 2007
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Cyclic Tuning

Select the Cyclic 1 Tab.

From the Top Menu, select Preferences.

Select interface basic or advanced.

Select each of the options and watch the fields gray out on the lower part of the screen.

Look at the Gains selection. You can reset all four banks to the default values.

Your heli will fly using the default values.

If you want to tweak the individual gains and rates, select the Advanced Interface. Set it up like you would set up a legacy tail gyro. Turn up the gain until it wobbles, then turn it down a bit. There is some trial and error here. Do this for the tail. Elevator and aileron can be tuned as you desire.

The numbers on this screen are a work in process. Yours will and should be different.

Check the phasing. See the manual.
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Last edited by Rickn816; Apr 11, 2010 at 06:54 AM.
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Old Apr 11, 2010, 06:38 AM
RCHN #150
Rickn816's Avatar
Lawrenceville, GA
Joined Nov 2007
5,997 Posts
Vibrations

Let's set up the heli to check vibrations.

Remove the head and tail rotor.

Put the heli on a carpet and start the motor. You previously selected Enable Logs on the Control Tab, so your 720 will automatically make a new file every time you power it up.

Run the motor at full speed for a minute. Shut the motor down, count to five and switch off the power.

Reconnect to the PC using the USB cable.

From the PC Setup software, select File, then Replay Flight Log.

The Log is contained on the internal memory of the 720. If the file (LOG0.BIN) is not present, recheck your settings.

When you see the animated heli window, click play. You will see the voltage through the 720 in the lower right, and the vibration levels on the lower left part of the window. The numbers here should be .2 or less. If not, consider a CNC main gear. Everything that turns creates vibrations.

If you are satisfied, add the tail rotor and repeat. I recommend that you carefully balance the tail rotor with blades. Most of the vibration comes from the tail.

Repeat the test. If the vibration now is more than 2, you need to find the problem.

Add the main rotor head and blades. You can run the heli on the floor, or take it outside and hover.

The vibrations should be between 1.8 and 2.4. Lower is better. With the MicroHeli CNC main gear, the vibrations on my TRex 500 in hover and FFF are about 2.0. I'm still working on getting a good balance on the tail rotor.
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Last edited by Rickn816; Apr 11, 2010 at 08:14 AM.
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