V-Bar digital flybar system
On the left is the Mikado head for the Logo 600. It includes the swash driver. The part number is #04042. This is installed on my Raptor 50v2.
|First off I am just starting with this new digital flybar technology so I am not an expert. I have a lot to learn but I also have a lot of tips from a beginner point of view. So far I have run across many things that while simple, are confusing if you have no guide. The following are a mix of tips, suggestions, and guides.|
before you buy the VBar you should realize that despite
the price, you will only receive four extension wires.
These four will connect the collective, aileron, elevator,
and rudder channels from your receiver to the V-Bar but
you will need a 5th wire if you plan on using the 'Bank
Switching' feature. Bank Switching is used so you can
have the helicopter perform different at the flip of a
switch. This feature is most commonly used so you can try
out new settings but is also used to select between
different flight styles. You can have one bank optimised
for FAI flying and another for 3D. This 5th extension
wire is not a normal extension (female to male) used to
extend the reach of a servo, but instead it is a male to
male wire. So make sure you order one when you get the V-Bar.
I did not know this so I had to make one. See the next
Multiple power connections - It is recommended that your power source should be connected to more then one place. Even though all of the positive and negatives are tied together, having two connections will help distribute the high current that can come from the use of high performance servos. In my case I needed a wire to connect the 'Bank Switching' channels from the receiver to the V-Bar so I made a reverse Y-connector. I did this with a standard 3" extension and a short male wire. I removed the signal wire going to the female connector. The signal wire was then soldered to the male connector I added so that the signal goes direct from the two male connectors. And the short male connector was soldered to the positive and negative wires of the extension. This worked out great but you do not want to do this if you are not proficient with soldering. This connection has to be reliable! This means doing things such as splicing into the positive and negative wires at slightly different locations. If you did the connections side by side and your insulation came loose then the positive and negative could touch. Your soldering skill also needs to be good. Solder should flow across the two joints, if it looks like a ball of solder sitting on top of the wires then you cannot trust this. You would be better off just buying a cable pre-made. Note: After initially writing this I now have a different regulator that has two power plugs to go to the receiver. I used one to go in the reverse Y cable and I put the other into 'Channel 4' of the V-Bar controller. So I have three places that power comes into my electronics, however two would be enough.
- rotor head. I looked for a technique to make the stock
Raptor head work but I was not able to find one I liked.
One technique would have been to leave the see-saw hub in
place but lock it down to prevent it from moving. This
would then provide the leverage but it would not solve
the 0 delta requirement. With the TT metal grips I think
the rotor grip plates could be modified or new longer
ones made to work. For me, the solution was to purchase
the rotor head for the logo 600 (part# 04042). This head
is designed for a 10mm main shaft just like the Raptor.
However the bolt hole is too high. You can see in the
picture on the right the new hole I drilled 17mm from the
bottom. I first drilled a small hole just to make sure it
aligned with the shaft then drill it out to match the 3mm
bolt. With the main shaft in the head block this helped
guide the bit to make the hole on the other side of the
Pre-Purchase - Power source/regulator. You really want to make sure your power source is sufficient! Batteries that are capable of high current such as Nicds or 3rd gen Nimh. And if you use lipos with a regulator make sure the regulator is good enough. You can read more about this on my 2nd crash report. Basically I had a linear regulator that could not keep up with the digital servos so I had to buy a switchmode type regulator.
#1 - swash type. This is actually not that confusing with
the Raptor 30/50/60/90 since your radio will already be
set to the correct type. For those with a 120 eCCPM
helicopter like the mini-Titan you need to change the
radio swash type to a '1 servo' setup. The V-Bar will do
the mixing itself for the eCCPM models.
#2 - trims. You will NOT use the aileron, elevator, or
rudder trims on your radio. All trimming has to be done
in the V-Bar. It would be good if our modern radios had
an option to disable the trims.
Confusion #4 - UP is DOWN??? This has to do with the 'Live page' - Elevator UP is referencing the helicopter going up aka nose up. This is very confusing. The Live page is suppose to be about the radio so terms should only be relative to the radio. In this case it would mean to pull the stick toward the bottom of the radio. I got this mixed up when I setup mine, to me elevator up meant move the elevator stick up to the top of the radio. They should have a picture of the stick position at the top and bottom of the bars. Or at least use words that are not common between channels such as say elevator forward, collective up, etc. Or maybe even say nose up for the elevator, just adding 'nose' to their label would remove confusion.
Confusion #5 - Easy setup Step 6 ERROR. With the Raptor it uses a mCCPM setup. Even though you set this in Step 1, if during Step 6 you adjust the 'Collective Travel' then it will immediately take on the behavior of an eCCPM setup. Meaning that as you move the collective stick on the radio you will see all three servos move (collective, aileron, and elevator).
Tip #3: Connecting VBar to Computer.
Be careful about this. Luckily it did not
cause a problem but I found out that any settings you
modify are immediately sent to the VBar the moment you
connect it. I brought my laptop to the field to make
adjustments to my heli. After making some adjustments I
put the laptop in Standby mode. After making a short
flight I went back to the laptop to look over some of the
settings. I made a change to one of the settings fully
expecting that when I connected the heli to the laptop
that the software would read the values from the VBar
unit. However I found out that instead of reading from
the VBar, it instead wrote to it. I was able to set the
value back to what it was but from then on I was more
aware of the state of the software. Basically if you
start up the Vstabi USB program it will show 'no
connection' with NOTHING to the right of that. When you
connect the helicopter to the computer the red box will
change to 'connected' and there will be a box to the
right of that indicating that it is writing to the Vbar
then will change to 'ready'. During this time it will not
matter what settings you have made in the program. It
will read from the helicopter and update the software on
the computer to match the settings stored in the Vbar.
Now this is where you need to be aware of the program
status. If you disconnect the helicopter then later
reconnect it without having closed the Vstabi program
then any adjustments you made one the computer will
immediately be sent to the helicopter. This can also be a
convenient feature. After understanding how this works I
now will make an adjustment on the laptop then I connect
the helicopter for just a few seconds to allow the update
and I am ready to go.
TIP #4: English. When you install the Vstabi software it ask what language and if you select English the icons for the program will have the '-1 en' added to them. This will get the file menu and some other things in English however if you use the Vstabi Easy program then the descriptions on the left will not be in English. To fix this go to 'C:\Program Files\VStabi\images-en' and copy the images to 'C:\Program Files\VStabi\images'.
TIP #5: Tail limit 64. Some tail servos will go limp (like no power) when the limits are set too high. In most cases this happens with a value greater then 64. Test this out for your servo. If you find you need a higher value to get the full mechanical travel then move the ball on the tail servo outward one more hole and try again.
TIP #6: Cycli gain 100/109. This <link> describes setting the Cyclic Gain to 100 or 109. For the Raptor you do not use geometry correction so you set the Cyclic Gain to 100. For a 120 eCCPM swash you could use geometry correction so you would use 109.
TIP #7: Tail settings. I played around with
different values and it can be very confusing. I had to
go to Wikipedia PID
Controllers to help me understand
how this controller loop works. In the end I came up with
Common Gain = 95, Acceleration=20, P=90, I=30, D=25. I
would recommend using these settings for the Raptor and
would also suggest at least starting out with these
values for other setups. If that does not work then set D
to zero and experiment with P and I.
Extended versus Ultra
When you adjust the 'Performance Main Rotor -
Cyclic Rate' it is changing the values of 'Paddle
Steering Intensity' and 'Bell' on the 'Flight Parameter'
tab. It will keep the Bell to PSI at a 2:1 ratio. Also
note that if you had different values on the aileron and
elevator then after you move the Cyclic Rate slider the
aileron and elevator values will be the same.
Bubble level on pitch gauge - As you can see in the picture I added a bubble level to my pitch gauge. The first step is to set the pitch gauge to zero degrees and place it on the blade. Place a 2nd bubble level on the blade grip. Adjust the collective so bubble on the grip is level. Next using some glue such as Goop (link) stick a bubble level to the pitch gauge and position it so that it is level. Next take the gauge off lay it down so the level does not move out of position. As the glue sets up test the pitch gauge again. With the gauge at zero both the level on the blade grip and the level on the gauge need to be centered.
The Crashes ...
Start Up: Just like with a Heading Hold tail gyro, do not move the helicopter until the unit initializes. After you power the helicopter up watch the swashplate for the sign that initialization is complete. You will see the swashplate bump up/down. This takes about six seconds.
Switching: Some people have said that using the flight
mode switch to switch banks has caused a crash. I do not
understand how this could be any different then flipping
an AUX switch while flying but for informational purposes
I thought I should let you know. During my inital setup I
used the flight mode switch to select the banks and never
experienced a problem due to this type of configuration.
Currently I only use the AUX2 switch to select banks. The
reason is that after I got everything set the way I like
it, I found Ultra Mode handles my ground manuevers,
standard aerobatics, and 3D all so well that I do not
have any need to have different configurations. I have
the AUX2 switch set to toggle between Bank 0 and Bank 3.
Currently all banks are identical but if I want to try
something different I can use Bank 3 to experiment with.
Here I will present both techniques. I will start with
the simple one first:
Step 12: Mechanical setup - Centering. Click on the 'Flight Para' tab then click on "Adjustment Mode", this will set all servos to center. Now go to the 'Swashplate' tab and start in the K1 group. This is the Collective servo. Start with the 'Center' at zero. Install the servo arm as close to straight horizontal as you can. Use the 'Center' control to get it level. Do the K2 group next. This is the Aileron servo. Set the arm as shown in <this> picture. Install the arm as close to center as you can then use the 'Center' control in the K2 group if needed.
Setup Notes: Do not use the 'Easy setup' due to an error in Step 6. With the Raptor it uses a mCCPM setup. Even though you set this in Step 1, if during Step 6 you adjust the 'Collective Travel' then it will immediately take on the behavior of an eCCPM setup. Meaning that as you move the collective stick on the radio you will see all three servos move (collective, aileron, and elevator). So instead of using the Easy Setup, use the Vstabi USB program and at the bottom/left click on 'Expert Setup'.
Step 1: Set radio swash type. Enter the System Menu, hold 'Down' and 'Select' buttons while you turn on the radio. Use the 'Down' button to get to [SWASH TYPE] and select '1 SERVO'.
Step 2: Set radio initial values. Enter the Normal Menu, with the radio on hold 'Down' and 'Select'. Go to [D/R & Exp] and set AILE, ELEV, and RUDD D/R to 100% each and EXP to LIN. Go to [PITCH CURVE] - NORM and set L=0, 1=INH, 2=50, 3=INH, H=100. Flip the flight mode switch to NORM.
Step 4: Connection. Start up the Control Panel. Click on the icon for 'VStabi 3.6.16 USB'. Now with your radio on, power up the helicopter receiver/vbar controller. Wait ten seconds then connect the USB cable from the computer to the helicopter. You will see this: . Next click on the 'Expert Setup' at the bottom left.
Software. On the 'Preset Setup' tab click on the 'Expert
Setup' button at the bottom left.
Step 7: Radio - reverse settings. Click on the 'Live' tab. In the radio go to [REVERSING SW]. Start with the Aileron. Move the stick to the right and observe the Aileron bar in the Live menu. The bar needs to go up. If not the change the Aileron direction in the radio. Next is the Elevator. Note that the top of the bar is labeled 'Down'. This should say 'Nose Down'. When you move the elevator stick toward the top of the radio (aka Forward) the bar needs to go up toward the label 'Down'. Yes, that is correct, up is down. As I said, if the label were changed to 'Nose down' then it would make sense. Next is Rudder, the Live page does not indicate what direction is right. I have ran it both ways and did not notice a difference. I ended up leaving it with right rudder moving the bar up. I chose this because on the Aileron bar, right is up. Next is the Collective. Move the collective stick up to the top of the radio and the bar should move to the label 'Up'.
Step 8: Radio - Sub-trim settings. Click on the 'Live' tab. On your radio center the trims for the Aileron, Elevator, and Rudder. The DX7 will remember separate trim positions for each flight mode so check all modes, Hold/Norm/ST1/ST2. Next go to [SUB TRIM] and set the Aileron, Elevator, and Rudder so that the numbers circled in the picture to the right are as close to zero as you can get. Next you need to do the same for the collective but first you need to center the collective stick. Flip the flight mode switch to NORM. Adjust the 'Hover Pitch' trim (at the front-left) to center it. Go to [PITCH CURVE] - NORM and on the bottom left you will see the IN and OUT values. Move the collective stick to a position that sets OUT=50. Go back to [SUB TRIM] and set the PIT. so the number on the LIVE menu for Collective is as close to zero as you can get.
Step 9: Radio - travel adjust. Click on the 'Live' tab. For each of the channels Aileron, Elevator, Rudder, and Collective adjust your servo end points to achieve as close to 1600 as you can. Go to [TRAVEL ADJUST] in the radio and use the 'select' button to get to each of the channels. On my DX7 I ended up with Aileron=108/108, Elevator=109/109, Rudder=109/109, and Collective=108/108.
Step 10: Software - servo direction. Click on the 'Swashplate' tab. Move the collective stick up toward the top of the radio and watch the leading edge of the main blades. The leading edge is the thicker side of the blade and the trailing edge is the thin side. When you move the collective stick up the leading edge needs to move up. If not then go to the K1 group and change the 'Reverse' check box. Next move the aileron stick to the right. The right side of the swashplate needs to move down. If not then go to the K2 group and change the 'Reverse' check box. Next move the elevator stick forward to the top of the radio. The front side of the swashplate needs to move down. If not then go to the K3 group and change the 'Reverse' check box.
Step 11: VBar sensor direction.
Step 12: Mechanical setup - Centering. Click on the 'Flight Para' tab then click on "Adjustment Mode", this will set all servos to center. Now go to the 'Swashplate' tab and start in the K1 group. This is the Collective servo. Start with the 'Center' at zero. Install the servo arm as close to straight horizontal as you can. Use the 'Center' control to get it level. Do the K2 group next. This is the Aileron servo. Set the arm as shown in <this> picture. Install the arm as close to center as you can then use the 'Center' control in the K2 group if needed. Same thing goes for the Elevator servo in the K3 group.
Step 13: Mechanical setup - level the heli. Level the frameset of the helicopter. Use a bubble level at the top of the frameset as shown in the pictures above. Place a magazine under the skids to get the heli level both fore/aft and left/right.
Step 14: Mechanical - collective links. Adjust the link from the collective servo to the collective pitch arm so that the indicator at the back of the collective pitch arm is aligned with the zero degree mark on the built-in pitch gauge. You can see which mark is the zero indicator in <this> picture. Next adjust the long links going to the blade grips to level a bubble level placed on top of the grips as shown in the picture on the right. I ended up with 70mm from center of the link holes.
Step 15: Mechanical - elevator centering. Set the main blades 90 degrees to the tailboom and bubble level on one of the blade grips. Rotate the rotor 180 degrees and check the bubble level. If it is centered when rotated to both the left and right side of the heli then the elevator is centered. If it is good on one side but not on the other then you will need to make two adjustments. One is the link to the elevator servo and the other is the long link to the blade grip. The first step is to adjust the link to the elevator servo so the bubble is off center the same direction. So if you see the bubble offset to the front of the heli when on the right side of the heli and offset to the back when on the left side then adjust the elevator link to acheive either the bubble centered on both sides, forward on both sides, or toward the back on both sides. If you got it centered on both sides then you are done. Otherwise the next step is to adjust the link to the blade grip. This will get one blade grip, move the bubble level to the other grip and do the same for it.
Step 16: Mechanical - aileron centering. Set the main blades inline with the tailboom with the bubble level on the front blade grip. In Step 15 you did two things, centered the elevator and set the blade pitch to zero degrees. So with this step the only thing that you need to do is center the aileron. The two links you will adjust for this step are the two that connect to the left and right side of the bottom ring of the swashplate. These two need to be adjusted equally. If you turn one link clockwise one turn then you have to turn the other one counter-clockwise one turn. Use these two links to get the bubble centered with the grip on the front and back side of the heli.
Step 17: Software. Click on the 'Flt Paras' tab. Next click on 'deactivate Adjustment mode' located at the bottom left.
Step 18: Collective Range. Click on the 'Swashplate' tab. Place the pitch gauge on a blade and set it to 11 degrees. Move the collective stick all the way up. In the K1 group, adjust 'collective' so the pitch gauge bubble is level at 11 degrees. Note this same adjustment can be done in the 'Pitch' group located at the bottom left. This will give -11 with the stick all the way down.
Step 19: Cyclic Range. On the 'Swashplate' tab set K2 and K3 'Distance' to 100. Go to the 'Cyclic' tab and at the bottom set 'cyclic gain' to 100. To measure cyclic pitch, start with the collective at zero degrees. Set the pitch gauge to zero and move the collective stick to a position that has the bubble on the pitch gauge centered. To check the elevator range rotate the main blades so they are 90 degrees to the tailboom. Hold the elevator stick full forward and then adjust the pitch gauge to level it again. The range you are aiming for is 10 degrees both directions. Adjust the 'cyclic gain' to get 10 degrees. Rotate the main blades to be inline with the tailboom then check the aileron range. This should also be 10 degrees. If not then it is probably due to having different servos on the elevator and aileron or having the ball a different distance from center on each servo.
Step 20: Tail setup - direction. Go to the 'Tail' tab. Move the rudder stick to the right and watch the tail control rod. The rod needs to move forward. If not then at the top-right change the 'Stick Reverse' check box. Next pick up the heli and rotate it so the nose moves left. Watch the tail control rod. It needs to move forward. If not then at the bottom-left change the 'Sensor Reverse' check box.
Step 21: Tail setup - center. Click on the 'Flight Para' tab then click on "Adjustment Mode", this will set the tail servo to the center position. Place the servo arm on the servo so the arm is straight up. If it is close but needs to rotate a little more then adjust the 'center' at the bottom-middle on the 'Tail' page.
Step 22: Tail setup - control rod. Adjust the tail control rod so the control lever at the back is 90 degrees to the control rod. Or another way to look at is if you imagine a line from the center of the ball to the center of the screw, that line needs to be parallel to the tail shaft. See the photo on the right.
Step 23: Tail setup - travel limits. As stated at the top of this page, there is an anomally with some servos that cause them to stop working if the limits are set too high (above 64). Click on the 'Flt Paras' tab. Next click on 'deactivate Adjustment mode' located at the bottom left. Now go back to the 'Tail' tab. Hold the rudder stick all the way to the right and adjust 'Dir A' or 'Dir B' to determine which one makes the servo move. Adjust the value for full mechanical travel. You should see the brass slider on the tail shaft just slightly go into the tail case. If the value is more then 62 then I would change the position of the ball on the tail servo arm. Go out to the next hole and try again. Once you get this correct then move the rudder stick full left and set this side. Again make sure the value does not exceed 62.
Step 24: Tail setup - piro optimization. Click the 'center' button, pick up the heli and rotate it. Note if the dot is not rotating the same direction then click on the check box 'Direction reverse'. With one full rotation the dot needs to rotate back to the top position. If not use the faster/slower buttons to adjust it. I ended up with +27 on mine.
Step 25: Tail setup - zero collective. In your radio go to the Pitch Curve Norm and move the collective stick to the middle so that the IN=50,OUT=50. Next click on the 'Set zero collective' button on the left side of the 'Tail' menu.
Step 26: Tail setup - default values. These are the values I changed from the software defaults: Acceleration=20, Rate=60, Common Gain = 95, P=90, I=30, D=25, Collective/Aileron/Elevator set to zero.
Cyclic setup - default values.
Flight setup. You will start out in Classic mode to do
trim adjustments so go to the 'Flt Paras' tab and click
on the 'Vbar Classic' button. Disconnect and test hover
the helicopter. This should be done when there is no wind.
If the helicopter constanly drifts one direction then you
will need to trim it. This can be done mechanically or by
software. If you used a swash leveler during setup or you
did the technique I gave in steps 13-16 then you know the
swash is mechanically level so the drift is due to the CG
being off. In that case I would use the controls at the
bottom half of the 'Trim' section on the 'Flt Paras' tab.
If you just 'eyeballed' the swashplate during setup then
I would assume it is not exactly level and I would adjust
the links going to the bottom of the swashplate. Before
mechanically adjusting the links I would check the CG. If
you find the nose is heavy and that is the direction the
helicopter is drifting then I would use the software to
trim it out. BTW: it is best to have the CG centered at
the main shaft obviously but I know sometimes that is not
the case with all the things we put up front now (vbar,
receivers, lipos, regulators, governors, mixture servo
and controller, etc.) Once you get the trim set for hover
then do a climb out and take note if it remains level. On
the Raptor it should but with a helicopter with 120 eCCPM
you may find it needs some trimming. Use the 'Fine
Adjustment' group to do this. Do an inverted climbout and
again make the appropriate trim adjustments.
Step 29: Ultra mode. Go to the 'Flt Paras' tab and click on the 'Ultra Mode' button. Move the slider for 'Performance Main Rotor - Gain' to 250. If you find the flip rate is too slow or fast then adjust the 'Performance Main Rotor - Cyclic Rate'
Step 30: Tip on Autos. With a digital flybar, the cyclic response is the same at 1600 as at 2200 since the electronics control the feel. With a flybar, the head response is sluggish compared to your flight mode head speed. As a result you get use to using more cyclic during and at the end of the auto. This change in response does not happen with a digital flybar. As a result I was over reacting at the end of the auto especially during the flar. I set my dual rate for autos to 80% and that solved my over reacting problem.