Update - Gaui 200 fbl w/ BestX

[DMala]

Hello everyone, I have been away from this forum for a while, quite distracted by a quad that I wanted to set up for aerial photography (line of sight) ..... Last February I got a used-like-new Gaui 200 V2 fbl with Microbeast V3 + USB adapter and Spektrum satellite (heli built but never programmed nor flown) and now I have finally found the time to work on it. I have replaced the 18A ESC with a Phoenix 25A and also replaced the skimpy motor bullet connectors with 2mm connectors.

To keep things simple I plan to start with both the Microbeast and the Phoenix factory setting. Basically the same for the radio settings (JR9303), I have reset a model slot and plan to start with minimal programming. Then over time I can figure out how to use a governor, tweak expo, etc. Any alternative suggestion? The Microbeast manual is very detailed and I find a bit difficult to clearly identify the steps to follow, but I am slowly getting there I think.....

[dynodude]

First thing you want to do is go to the sticky at the top of this forum. Nexgen put together a very nice vid series on setting one of these up in a Gaui 200. It is veryeasy and you can go through it step by step. It is what I used and I was a FBL newb. I followed his vid and my bird hovered and flew right from the get-go. The other suggestion I have is to skip the pre-set flight modes in the Parameters menu, and go straigt to TX mode. It will give you the most control to dial the BX in just the way you like it. Once you become familiar with the BX, you will find it is a very easy system to use.

[DMala]

Thanks, I saw the videos by Nexgen before I bought this heli and I watched again the ones on the BeastX setup.

Thanks for the tip on the "transmitter mode". I was not aware of it and probably I would have ended up with parameter b set to sport, which is not what I would want to get started with.

[dynodude]

TX mode will allow you to have greater control over your rates and expo, as I believe those are preset in the "canned" modes. The best advice I can give you is to treat your radio and the BX as a system that you can use to create exactly the type of control for your style of flying. As a couple of suggestions I would say first, start with your cyclic gain set at about the 7:30 position. If you have any aileron/elevator oscillation hovering turn it lower, but use very small adjustments. It is quite suprising how low it adjusts and is stable. Also, when you are adjusting your expo, you can also use the cyclic feed pot to really dial in smooth. Hope this helps. If you have any other issues just give us a holler.

[DMala]

Thanks. Yesterday I managed to do almost all the setup steps and also selected transmitter mode.

I believe that the last few issues left to address are that there is an exaggerated amount of pitch range in both directions (way past the 12-degree mark on my pitch gauge) and that maybe because of that the elevator servo ball link popped off the servo arm while performing step L, Adjusting the cyclic swashplate limit.

I am thinking that to address both I should reduce the pitch servo travel limits on the radio. Should I then repeat step L? It seems that to get the blue led in step L it is necessary to have really extreme travel movement values which may not be feasible with the mechanical setup that I have right now.

[dynodude]

Adjusting the travel limits in the TX affects the speed of the servo, not the travel range. Set-up menu K is where you will adjust your pitch limit. Set-up menu L shows the BX the max amount of cyclic available that it can use for stabilization. As I understand it, there is no adjustment for total cyclic, other than to use the rates on your TX for Ail./Elev. The goal in L is to have maximum cyclic without binding and a blue light, indicating there is sufficient travel for FBL use. Did you get a blue light at 6 deg. in menu J? This shows the BX that you have the correct geometry for FBL use, and is very important to try to get that blue light as close to 6 deg as possible. Typically, on these helis you have to use a ball on the inner swash ring without a stand-off. You can also just flip the ball around if you don't have one. As long as the link popped off in L, that is all you should have to re-do.

[DMala]

Originally Posted by dynodude

Adjusting the travel limits in the TX affects the speed of the servo, not the travel range. Set-up menu K is where you will adjust your pitch limit. Set-up menu L shows the BX the max amount of cyclic available that it can use for stabilization. As I understand it, there is no adjustment for total cyclic, other than to use the rates on your TX for Ail./Elev. The goal in L is to have maximum cyclic without binding and a blue light, indicating there is sufficient travel for FBL use. Did you get a blue light at 6 deg. in menu J? This shows the BX that you have the correct geometry for FBL use, and is very important to try to get that blue light as close to 6 deg as possible. Typically, on these helis you have to use a ball on the inner swash ring without a stand-off. You can also just flip the ball around if you don't have one. As long as the link popped off in L, that is all you should have to re-do.

Aha, when I read about Parameter step B in the manual I did not realize that servo throw on the transmitter becomes servo rotation rate on the BeastX. Thanks again.

In any case, I think I got it now. I went back to Setup step K and regulated a max pitch of 12 degrees in both directions. Then I went back to step J and like before I got the blue light with no effort. No need to invert the swashplate ball links or change them to those without standoff. Beginner's luck? Then I repeated again step K with very minor additional adjustments, and then this time I got immediately a blue light and clearly free servo movements at step L.

So I guess that at this point I will give a final additional check to the tail servo directions, modify the normal mode pitch curve to start with about - 5 degrees at zero throttle like I have on my flybarred EP200, and I will be set to give it a cautious spin! The tail gyro gain is set to 75% as a starting point as I normally do on traditional gyros, but I am now reading that the BeastX manual recommends a lower value to start with, and I will change the gain accordingly.

[DMala]

Well the first try did not goo too well, nothing catastrophic but as I spooled up there was some moderate sideways wobbling (I had installed a training gear and the skids were held a few inches off the ground by the carbon rods), Then all the sudden as I slowly got into positive pitch past the throttle mid-point, the skids got lighter but at the same time the heli suddenly flipped on the right side and one blade struck the ground. This was way faster then when you have the swash slightly off and the heli pulls a bit on one side. Luckily it seems that besides the ruined blade (cheap and previously chipped already) and the elevator servo ball popping off (the one that came off before: I replaced the servo arm now) there were no other consequences.

I had the swash gain at 100% because I wanted to get a very initial feeling of the stock settings, prior to reducing it as indicated by dynodude above. Now I have turned it down to the position that was suggested.

[DMala]

OK, I am reading in the tuning guide on the BeastX forum that the stock foam tape may also cause rolling on takeoff. Actually I am still using the original tape which I detached and put back a few times for checking the connections and binding the unit, so my situation is even worse. I will replace the foam tape with 3M4011 before trying again.

[dynodude]

Also, where do you have your BX mounted? If you have it on the extension on the front of the frame it gets alot more vibration. I mount mine inside the frame, right behind the front frame spacer. Less vibration, and more protection in a crash. The 4011 tape is the way to go. I have never used the stock tape, but I have never had a problem with the 4011, and I use it on both of mine. You really do need to turn that cyclic gain down. These little birds like it low. Use very small adjustments on this, but I would start with it at about 7:30. If you notice any oscillation in the cyclic, land and adjust. Also, the more head speed the better. Good luck, and keep us posted. It takes a little messing with, but you'll get it, and once you do, it's sweet.

[DMala]

After replacing the elevator servo arm I went again through the entire setup menu, better centering all servo arms and making sure even more carefully than before that the pitch is set as per the manual's instructions. Just to test the hypothesis that the tip-over was due to inappropriate mounting tape, I spooled up the heli while holding down the skids (with the BeastX in the original position on the front extension and with the original foam tape in poor condition) without the blades, and indeed I observed a clear wobble of the swashplate as I increased the throttle.

So I have now installed the Beast X inside the frame, using Scotch 114 permanent mounting tape (also recommended in some online posts), and with the connectors facing forward. The wiring to the unit is slightly loose.

I then spooled up again and now as I increase the throttle the swash moves up very smoothly. However as I pass the mid position of the throttle, the swash takes a very pronounced slant to the right, is this normal?

[dynodude]

Off hand, I would say no, it is not normal for it to tilt in any direction. But, as most people will tell you, FBL units do not behave "normally" while on the ground. Holding it may be introducing some vibes causing it to tilt. If you have done your set-up, centered your servos dead nuts, set your pitch at 0 at mid-stick, and have equal pitch + and -, then go for it. This is where a set of cheapy Align plastic blades comes in handy. Just spool it up nice and slow until it gets light on the skids. I would also limit my pitch in my pitch curve to have just enough to get it off the ground, and have my rates at about 60% until you have it sorted out. Your first couple of hovers are going to be sorting out the settings in the BX; pot settings, parameter settings, etc. I was a total newb when I got my first 200 BX. I watched the vids, did my set-up twice and even though I was nervous as hell, it hovered on the first try. That's not to say it didn't require adjustment, but these things do work and they work really well. Don't get caught up in that "don't-touch-the-cyclic-while-spooling-up" dogma either. If you are tilting to one direction or another during spool-up, you can level it out with the stick. Actually, one of the nice things about FBL is that it will hold a cyclic command until another one is given. Expect your tail gain to be low also. I'm sure you will get i sorted out. The learning curve isn't that steep.

[DMala]

Great advice, thaanks. Actually the situation was worse than I thought, and to some extent difficult to explain. After testing the swash response while holding the heli, and posting my question, I found the tail slide linkage (the plastic think shaped like a L) broken, the tail rotor shaft badly bent, the upper tail pitch lever also bent, and the slot for it in the aluminum slider all jagged (probably by the pin of the upper pitch lever). What the heck had happened? The best I can guess is that since I am not familiar with the V2 tail, I may have not noticed that there was a poor fit of the pin of the pitch lever with the slot of the slider (due to play of the pitch lever itself), and while spooling the motor at high RPM everything came loose. Maybe.

In any case, I spent more than two hours to rebuild the tail. I have straightened the upper pitch lever, replaced the shaft (I have several V1 NIP around), filed the edges of the slide slot to be smooth, opened up the "fork" where the upper pitch lever slides into to eliminate play, checked and applied loctite to all screws, etc. Then I went back to the BX to reduce a bit the slider travel and to check all the tail servo menus. Now when I spool up the swash moves up nice and steady, so I am just about to give it a new try!

[DMala]

Well, BeastX and I do not get along well, evidently...... After moving the unit to the center of the frame, and bench-testing it, I had another tip-over, see the second one in the video.

After that I moved the BX back to the frame extension, turned it with the wires facing back, and there was a slight improvement in the sense that instead of flipping suddenly past mid-throttle, it leaned to the left slowly enough to give me time to react.

So it seems that the mounting method and position may be the issue. The heli itself does not seem to have visible vibrations, I can spool up to full throttle without blades and it stays still without shaking, so I would suspect some high-frequency vibration or an issue with the wires carrying some vibration. Today I will go to buy some 4011 tape and try that, one layer first and then two layers, and post on the BeastX forum to see if some other idea comes up.

BeastX problem May 2012 (1 min 28 sec)

[BHChieftain]

Hi,
I suspect your training gear is the problem-- I think when you are spooling up you are spending way too much time on the ground and the feedback from the ground thru the training gear is confusing your gyro big time. Try scrapping the training gear, and after spool up get her into the air ASAP!

Chief

[dynodude]

+1 on ditching the training gear. I could see when you were spooling up that it was kind of bouncing a bit. Until you get this sorted out, I would run about 75 % max on TC And a very slow PC with say 8 deg. max. This will give you just enough to get it light on the skids and in a hover. I assume that there is no trim or sub-trim in your TX , but double check. Also, you might try turning down the cyclic feed on the BX a little. Again, it is just to slow things down some. Those tip overs are almost always caused by vibes. Lose the training gear and try some 4011 and I think you will improve your chances of success.

[gratefulfrog]

Hi!

It sounds to me like the problem may be more than vibrations, although all those bent and broken parts certainly need to be replaced.

Generally speaking, FBL needs everything to be close to mechanically perfect. And it needs good tough cyclic servos. Digital with metal gears and metal cases. Also, you might be getting BEC brown out with that Phoenix 25's linear BEC. I didn't notice if you are running 2S or 3S, but I would go for 3S as I have, and put in a separate BEC.

If I were you I would take apart the head and be sure that the swashplate is *PERFECTLY* level at all points from -100% to + 100% of the full pitch curve. This requires a leveling tool since eyeballing is not good enough for flybarless.

Once you have done that, and ensured that your cyclic servos are good, smooth fast a powerful, then be sure that the blade head is perfect, tracking is perfect and blades are perfectly balanced. You may find that trying various blades makes a huge difference.

I don't think that the training gear has anything to do with it, if you initialize the gyros from a 100% steady and 100% level position.

My Gaui 200 V2 flies like a dream, the config is:
3S
CC Phoenix 25 ESC
CC BEC set to 6V
Savox SH-0261MG on cyclic
Savox SH-0262MG on tail
Futaba gy502 on tail
Skookum SK-360 on cyclic
Motor: scorpion 3900kv
FBL 205mm main blades

It is quite heavy with those servos+bec+2 gyros+all the wiring, but the motor and 850 nano-tech lipos can handle it. I fly 5m30 to and come off with 20% battery remaining.

However, I don't like the construction of the head, and in general I think the G200 is quite fragile. I'm wondering about an upgrade to an X2. I certainly would not invest any more in my 200V2, despite the beautiful way it flies!

Hope this helps!
Ciao,
Bob

[DMala]

Thanks for all the answers and for taking your time to help, below are some details/comments on the issues raised, it is not that I want to argue but it may be interesting to discuss more in depth:

- I do not have a swash leveling tool. Gratefulfrog, are you thinking that a minor error in swash leveling can cause a complete inability to take off? I can see how with FBL you need precision, but I would have expected small misalignments to cause poor hovering and inaccuracy in cyclic input, not complete flipovers at take off. I would imagine that such degree of magnitude of response to small swash leveling problem would have been observed before, has it?

- The heli is basically stock, with a Hyperion 2S battery. The servos are Ino-Lab HG-0202-HB on the cyclic and Ino-Lab D201HB on the rudder. I did think of a possible starving of the BEC but on the other side many report good results with BX and the stock 18A ESC, I would have expected the Phoenix to be an upgrade, no? One thing to look at is that I am using the ESC as it was in the package (it says that it is ready to use). I will check now the settings with the Castle Link and verify if I see anything strange.

- There are a couple details related to the servos that at first I did not consider relevant, but may be worth a fix now . I bought the heli on the RC groups trader, as new, built but never programmed nor flown. The condition was in fact just perfect and I have no reason to believe this was not true. However the person who did the build placed a few drops of epoxy on the servo arms ball linkage screws, to secure the ball linkages to the servo arm. The epoxy covers the ball standoff. From what I can see there is no mechanical interference and I have kept them as is, but I think that now just in case will install the stock servo arms and ball linkages, without using any glue.
Also I noticed that the pitch servo body is a bit smaller than the slot in the right frame plate, and it wiggles a little bit when the servo arm reaches its endpoints. I will insert some shimming to keep it from moving.

- I used the training gear only on the first flight, but the problem has recurred regardless of it. I do not plan to use it anymore anyway, to avoid adding another variable that could further confuse the problem.

- On the BX forum most responders think I have set the swashplate response direction wrong. I will check again, but during the repeated checks of the setup that I did before, the swashplate would stay nice and flat when tilting the heli in all directions.

- yesterday I took a break from the BX (went fishing....) and during this week I will continue the troubleshooting. Another thing I want to do in addition to the plans I mentioned already, is to start fresh, reset the unit and the radio and re-program everything.

Thanks again to everyone for helping.

[dynodude]

I don't know why it didn't occur to me before, but I'm glad someone else mentioned it, and that is to recheck your swash correction. Swash should move opposite of the direction the heli is tilting.

[gratefulfrog]

Hi!
Never worry about asking questions!! We're here to help!

Originally Posted by DMala

- I do not have a swash leveling tool. Gratefulfrog, are you thinking that a minor error in swash leveling can cause a complete inability to take off?

Yes, I am saying exactly that. The "flip at takeoff" can be a result of inaccurate swash leveling. Also, as you mentioned below, the servos not solidly mounted, and also binding on the ball links. Basically, everything involved in the set-up of the head, if not done perfectly, can lead to unwanted flips. Also, the BX could be incorrectly set-up or even defective (unlikely).

Originally Posted by DMala

I did think of a possible starving of the BEC but on the other side many report good results with BX and the stock 18A ESC, I would have expected the Phoenix to be an upgrade, no?

If you read the Phoenix manual, you can learn how a linear BEC works. The max BEC current has nothing to do with the 18A motor current of the ESC. You can see how your ESC is doing by disconnecting the motor wires and connecting the Lipo. Play with the heli's gyros and servos by moving it around for 1 or 2 minutes and see if the ESC gets hot. If it is hot, not just warm, then your electronics circuit is drawing too much current and you need a separate BEC. I mean really hot, I burnt my finger-tip touching before mounting the separate BEC.

Originally Posted by DMala

There are a couple details related to the servos that at first I did not consider relevant, but may be worth a fix now.

Here's a rule of thumb: Used helis require more setup work than building from a new kit. Sadly, I am still learning that rule, the hard way. I just spent nearly $1000 on a used Logo 400 SE, that "just needed to bind the RX and it was perfect". So far I have spent 15 hours fixing all that is wrong with the machine, and am still no where near ready for a test flight.

So what do you need to check (and fix!)

• all screws tight, all metal to metal screws locktighted.
• all bearings properly mounted and free of slop
• all ball links move freely, no slop
• main shaft, spindle, tail shaft all perfect - for a little heli like the G200, why not just change them to be sure?
• main gear not worn, all teeth perfect
• correct backlash between main gear and motor drive gear
• wires routed away from any moving or hot parts
• servos wired to correct rx and BX channels
• center of gravity +/- ok
• tail belt or drive shaft in good condition and proper tension
• main blades perfectly balanced, tail blade same weight
• then the actual setup:
• servo arms perpendicular to links at mid stick, no subtrim -> some fbl units see subtrim as a command so beware - anyway it's always best to not need it;
• swash 100% level over full pitch range
• swash action correct for pitch, elevator, aileron
• swash range does not bind
• same questions for tail slider and tail servo,
• then gyro compensation:
  • swash: tilting heli nose down cause swash to til nose up, roll left causes swash right etc
  • tail: nose left causes tail rotor to compensate right,
• Finally, dynamics:
  • main blade tracking
  • tail rotor neutral position compensation at hover in rate mode.
  • generally look for vibration and noise and fix any!

Yes, that may sound like a lot, but that way it works. If you don't do that, it still may work, but you are just gambling on the previous owner's set-up working with your radio setup. Is it worth the risk?

Originally Posted by DMala

Thanks again to everyone for helping.

It's our pleasure.
Ciao,
Bob.