The Basics Of Flybarless RC Helicopters & Electronic Stabilization
Flying with a flybarless (FBL) head also called a Bell rotor head on RC helicopters is nothing new for the larger scale crowd as many big scale birds or scale birds with multi bladed rotor heads have been around for years.
They were extremely sensitive and difficult to control, not to mention the ballooning issues in fast forward flight (where the bird would pitch up if you didn’t hold in forward cyclic) was a constant worry.
Most average people in the hobby (sport, general, semi scale, 3D, and certainly beginners) would have never even considered using a true Bell rotor head with no flybar stabilization. Well, those days are gone thanks once again to the huge improvements in electronic miniaturization and gyro / accelerometer technology. Going flybarless is now a reality and has some wonderful benefits over the trusty old flybar for all types of RC helicopter flying.
With costs coming down all the time, FBL systems are getting more and more popular. Most RC helicopter manufacturers now offering most of their RC helicopter kits in both flybar & flybarless versions. Even the entry level micro segment are embracing this technology such as Blade with their
and other Blade heli "X" (flybarless) versions offered in most of their single rotor lineup now.
I have 8 helis now that are using electronic flybars and I personally feel once you fly with one, chances are you won’t ever go back to a mechanical flybar.
What Does A Flybarless System Consist Of?
Most electronic flybar systems consist of the gyro sensors and the mixing/control unit. These can be combined in one unit as shown here with Skookum Robotic’s SK-720 electronic flybar system, or they can be separated like Align’s 3G or Futaba's CGY-750 3 axis gyro systems.
All micro sized helicopters with electronic stabilization will generally have a combination control unit that incorporates the receiver, ESC, and the flybarless stabilization gyros.
The other part of a FBL system is naturally the head itself. There are various designs of collective pitch FBL Bell type rotor heads but the 3 main types I have listed below (I'm just showing two bladed heads, not multi since I have limited experience with multi and am all for keeping it that way). The main thing to note on all examples however is there is no flybar.
First up is the non integrated washout type.
This design uses a washout (also know as a swash driver or swash follower) that is a stand alone unit (circled in green). It is clamped onto the mast to transmit rotational forces to the upper half of the swashplate to keep it correctly phased with the rotor head.
Next is the integrated washout type FBL head.
This design eliminates the washout/driver/follower base and places the washout arms directly on the lower part of the head block (circled in green). The three advantages with this design over the separate washout is setup/head build is easier since you don't have to mess with washout height setting or angle phase.
Parts count is down slightly and the mast can usually be shortened a bit to bring the rotor disc down closer to the helicopter's center of gravity. In my opinion, from a purely mechanical workings point of view, this is the overall best design of all three; but that is just my 2 cents.
Last up is the DFC head.
No green circle in this photo because the washout has been eliminated. I have an entire
write-up on DFC
and encourage you to click on that link to read about DFC if you don't fully understand how it works and some issues to be aware of with it.
How Does It All Work?
First off to understand how a FLB system works you need to know how and what a flybar does. My page
here on flybars and head types
covers that in detail, but a very simple explanation of flybar function is to add stabilization to the rotor disc by automatically changing the cyclic pitch angles of the rotor blades to help make cyclic control much more manageable.
As the name suggests, flybarless (FBL) does away with the flybar and with the help of electronic stabilization systems, "virtually" replaces the flybar (why they are also called “virtual” or "electronic flybars"). Once again we owe this to the scale boys and girls since they were really the ones to first experiment with electronic stabilization systems on their no flybar birds. I remember reading several articles a number of years back when solid state heading lock gyros were first coming on the market – the Futaba GY240 to be exact.
More and more scale fliers using Bell heads (no flybars) were now putting not only a tail gryo in their birds to detect and correct for unwanted yaw movement, but they were also installing two more gyros mounted vertically to pick up the pitching and rolling movement of the heli.
The aileron (cyclic roll) servo was plugged into the gyro that detected roll, and the elevator servo (cyclic pitch) was plugged into gyro that detected pitch. Now when the heli would pitch forward for example the gyro that detected pitching movement would send a command to the elevator (cyclic pitch) servo to have it tilt the swash backwards to automatically bring the bird back into level flight.
This is the basic principle of how all electronic flybars operate and as seen in the picture to the right of a typical flybarless sensor that has the 3 solid state gyros oriented within the sensor just as if 3 separate tail gyros were used to detect yaw, pitch, & roll.
The same cyclic pitch changes that the mechanical flybar would impart to the main rotor blades are now done by the two (vertical) electronic gyro sensors that detect the pitch and roll attitude of the heli and then move the servos to tilt the swash to make the precise and quick cyclic changes.
You can see this with any FBL setup that uses an electronic stabilization system and it is actually how you test to confirm the system is working properly. If you are holding the bird and tilt it forward, you will see the swashplate tilt backwards. If you tilt the bird left, the swash will tilt right.
How Does Flybarless Feel?
One of the most frequently asked e-mail FBL questions I get is "how does it feel or fly compared to a flybar". Well it is quite hard to explain in words but the heli "feels" more locked in. By that, I mean it tracks better while in flight like it's flying on an invisible set of rails. For example, with a flybar bird when you pitch the nose forward to get the bird into a fast forward flight direction, if you center your forward cyclic stick the heli will gradually slow as the flybar slowly tracks back into a horizontal plane causing the main rotors to do the same. With an electronic flybar, the bird will stay pitched forward in the exact same attitude after you center your cyclic and you don’t have to keep holding in a little forward cyclic to keep it tilted at the same forward pitch angle.
This actually makes a lot of sense when you consider the same heading lock gyro technology that is used in the tail is also now being used for your cyclic. If you pitch the bird forward at a 30 degree angle – it will lock on that flight path more or less until you give a cyclic command to do different making cyclic stick counter corrections more pronounced. Now that is a very simplified explanation of what it feels like. Depending on the setup and in many cases how the electronic stabilization is programmed, you can vary the feeling quite a bit to the point they will mimic mechanical flybar response fairly accurately. Another way is to say FBL feels more like a simulator heli in some respects – but again it depends on the specific flybarless system you are using and how it is setup/programmed.
One thing is for sure, during a hover if you have the gain set right – the birds can hold very still and usually don't require the same level of cyclic correction from the pilot to remain perfectly steady but do require more pronounced cyclic counter corrections as I just mentioned. You still have to actively pilot them however, it is not hands off hovering by any means! I also feel much more confident now performing more basic aerobatics that I never felt comfortable with before. For me (not being a 3D guy), FBL has certainly helped take the edge off and I find myself trying more demanding flying such as inverted hovering, flips, stationary rolls, combination's, even tic-tocs & rainbows. The crisp, responsive, and locked in cyclic control obtained from using a flybarless setup while performing aerobatics gets very comforting and addictive, but I know some who hate that feel so it's certainly not for everyone.
I have two T-Rex 600ESP’s, one with the 3G system and one with a flybar. Guess which one gets all the air time now? To be honest, the main reason I got the 3G flybarless for one of my 600’s was to eliminate the flybar on a scale build of a new Bell 222 I just finished.
Unfortunately, I am having way too much fun with the 3G flying sport; I can’t for a second see giving up all that performance and fun just to have a scale 222 with no flybar. So for now, the 222 will remain "flybared".
What Are The Benefits Of Flybarless?
As I was just mentioning – performance is a big one! Without the added drag of a flybar and the paddles, not to mention a certain amount of extra weight in all the flybar head hardware, there is a noticeable increase in power & performance. For electric power, this also equates to slightly longer flight times. Overall flight speed is also up slightly (again due to a cleaner head and less drag off the flybar). Cyclic input is more immediate and less washed out feeling. The birds fly so locked in feeling and they track through the sky with amazing precision - like they are on rails.
The other obvious advantage is the reduction in head hardware and parts count makeing crash damage both less costly, and in some cases less damaging. You are basically eliminating not only the flybar and paddles, but also the flybar mixing cage assembly along with the washout base guide pins on the head and usually 4 pushrods.
In stark comparison, a pure Bell rotor head seems almost naked with only the head, the washout, and two single pushrods (for a two bladed rotor head) that go from the swashplate up to the two main blade holders.
This picture on the right is of a conventional mechanical flybar rotor head (Hiller type head) - lots of components when compared to the picture of the flybarless Bell type rotor head at the top of this page.
Flybars also tend to eat up tail booms and canopies in most respectable crashes. Eliminating that long piece of steel with heavy paddles on each end twisting and flopping about like some angry ball & chain while your bird is frantically dancing around doing the "funky chicken" usually means less damage. You may come away with only a bent main shaft, head axle/feathering shaft, and fragmented rotor blades – if you’re lucky.
Tiny micro collective pitch helis like the Blade mCPx, 130X, and Nano, are only possible because of their FBL AS3X electronic stabilization systems. A complicated Bell/Hiller mixed flybar/head and associated components would be so tiny and fragile, it would not be practical to use on a micro not to mention nearly impossible to work on for all but skilled watch makers. On top of that, micro flybarless systems are what keep such tiny collective pitch helis somewhat predictable in nature and flyable.
What about looks? Yep, that's after all why I decided to get a FBL system in the first place, to make a scale bird look better – unfortunately the performance benefits won out in the end! Even if scale is not your cup of tea, a flybarless head looks good – clean and simple.
The latest featured offered in some flybarless stabilization systems now is "rescue" or "save" mode which will level out the heli or put it back into an upright orientation when activated by the pilot. Moreover, some systems feature a training mode that will make a collective pitch heli almost behave like a stable coaxial. The MSH Brain/Ikon is one example which you can program in a maximum amount of roll or pitch and the heli will never fly over those limits.
What About Downsides/Disadvantages?
No, nothing is perfect and a virtual flybar is no exception.
Cost is the biggest one (talking regular size birds here, not micros), but the differences in prices are coming down all the time. I can see the day when both versions (flybar & flybarless) are pretty much on par with each other. One thing I haven’t mentioned yet is almost every electronic FBL system on the market now also incorporates the tail servo gyro in the sensor. This means you don’t need to purchase a separate tail gyro and that money can go towards the flybarless system. In the end you may only have to pay a couple hundred bucks if that difference by the time all is said and done (depending on the system and the application naturally).
$200 beans is still a fair chunk of change for most of us and I haven’t mentioned servos yet. Yes, you will need good high quality, high speed, and high torque digital servos for most FBL systems. Remember, the same heading hold gyro technology that is used in the tail rotor gyro is now being used with your cyclic/collective servos and therefore for it to function correctly, requires fast response times.
If you recall from the flybar page I linked to earlier, one of the other important functions of the flybar is to take some of the load off the swashplate servos. With no flybar, the servos are doing 100% of the workload to move the main rotors blades so they have to be powerful enough. Most intermediate to advanced RC heli pilots will already be using good strong & fairly fast digital servos on our swashplates, but definitely double check the specs on your electronic FBL system to make sure your servos meet the speed and torque requirements, not to mention the higher power loads these servos will be pulling. I for one would not power the on-board electronics on any larger flybarless heli with a BEC. I use dedicated LiPo and LiFe RX packs only!
Setup is also a little more complicated and in some instances – grossly complicated. Case and point, the HeliCommand Rigid flybarless system I use on my Bergen Intrepid turbine helicopter was a nightmare to setup correctly – it literally took me weeks/months to get it where I liked it. On the other hand, systems like Align’s 3G/X are fairly simple to setup that a monkey could figure it out (I’m living proof of that).
Reliability??? This is my main concern with electronic stabilization and perhaps it shouldn’t be a concern at all, but I have to at least mention it. Mechanical flybars have been around for years and are proven. Sure there are more mechanical moving parts that could loosen, wear, or even come flying off the bird if you are not looking after things, but in general – flybars are bullet proof.
So are electronics, but they can fail or hiccup due to a poor connection, low voltage, loose gyro sensor, etc. Again, not something to dwell on and face it, when was the last time one of your tail gyros failed in mid air? That is the question I ask myself when I’m looking for reassurance as I spool up. I'm sure after flying several years on flybarless, I will come to think of them as bullet proof as mechanical flybars. UPDATE: In the past 3 years now of flying with FBL, I have yet to have a FBL related crash. I have certainly experienced some funny & weird stabilization characteristics from time to time, most likely due to a poor FBL programming setup on my part; but no all out FBL in flight failures. I guess the reliability fear can now be put to rest (knock on wood).
Lastly there is firmware/software updates. If you really hate performing software updates on stuff, flybarless is likely not for you... It seems updates are as much part of FBL systems these days as is correct setup. The nice thing is with the internet at our fingertips, there are generally many tutorials on the updates, what they do, and suggested settings.
Should A Beginner Get A Flybarless RC Helicopter?
Okay, another very popular question I get asked almost daily! Simple answer – yes, no, maybe... As you see – I can’t answer it. It depends on the person, what they are flying, how they are learning, and of course their budget. That said, I feel at this point in time, a beginner who is self learning should stick to a flybar and here’s why (again, this is for regular sized birds, not micros with stabilization systems).
For most beginners just getting into single rotor collective pitch is a big commitment in time, resources, and of course the all mighty buck. Flybarless (at least right now) is just one more added expense/complication that could go towards more battery packs, a good computerized charger, a step up to the next size heli, a good flight simulator, one step up in computerized radio, etc.
This pushes a FBL system pretty far down the priority list for the marginal advantages offered at this level of flying when there are so many more beneficial ways to spend your hard earned cash and stretch your RC dollars.
Setup as I said is also more difficult seeing that not only do you have to understand the programming/adjustment of the flybarless system, but on top of that, most require that you are able to at least hover and fly some simple circuits to set the gain of the cyclic gyros correctly. If you have someone with FBL experience to help you out or are getting one on one lessons from an instructor who could setup the system properly, then that would certainly be okay and is a great option.
To really put this "difficult setup" issue in perspective, think of tail gyro setup. This alone can be very difficult for a newbie to grasp and get their head around. Flybarless essentially adds two more gyros to the mix and anywhere from a few to well over a few dozen other parameters to set correctly - much of it all abstract. Mechanical setup has to be nearly perfect as well. In short, it's less forgiving than a flybar.
Some FBL systems also do very funny things when training gear is attached or while performing ground handling exercises. Just like a heading lock tail gyro that can get confused while on the ground from either vibration or command input induced feedback, the two cyclic gyros can also get confused from training gear oscillations or get stuck in a feedback while the heli can't move freely as it does once airborne.
I only say some, not all. If you have watched the
nose-in hovering video lesson
I have on day 10 of the flight school, you will notice I'm flying with a flybarless Trex 600ESP with the 3G system and with training gear on. It was perfectly fine and reacted almost the same as the flybar version while performing ground handling exercises. Most systems will give warnings if training gear should not be used, so take that into account if you have your heart set on learning on a flybarless machine - make sure you know the flybarless system will function okay with training gear in place.
Lastly, most virtual flybar systems offer increased performance and crisper more reactive cyclic control. For a beginner, this is generally not what you want or need. There is a reason soft head dampening and lower head speeds are recommended for beginners – so they don’t over control the cyclic. Most flybarless heads are set-up with stiff dampening and require faster head speeds to work correctly; not all, and it depends on the system as many now can be tamed down to be less reactive, but in general, electronic flybar systems give sharp and instantaneous cyclic response and therefore are not perfectly suited for a beginner.
I've also been seeing a lot of misinformation lately that states things like a flybarless heli with electronic stabilization is easier for a beginner to learn on and in most cases that is just not true (with the exception of units like the MSH Brain & Ikon that have that beginner feature)! It feels different, but it's certainly not easier in most cases not to mention some training gear compatibility issues. So watch out for all the "easy to learn on" flybarless hype right now - there's a lot of it! The only way a flybarless stabilization system is truly easier to fly for a beginner over a conventional mechanical flybar is when they are paired with "auto pilot electronic stabilization systems" that use CCD cameras or GPS to detect heli movement and correct for it giving a true hands off the sticks flying/hovering experience.
The learning curve for a beginner getting into collective pitch is already steep, flybarless pushes that curve to near vertical! Just keep that in mind. It doesn't mean it can't be done and we are all different in our abilities, but I know if I had to learn all this flybarless stuff when I was first starting out in the hobby on top of everything else, I likely would have never got off the ground - but that's just me - monkey brain ;)
, I honestly can’t tell you what is best since that depends on your needs and because this is such a new and rapidly changing area of our hobby, new stuff is hitting the hobby shops all the time. Hopefully however, my humble little recommendations here will at least give you an idea of what is out there, what to look for, and some general costs.
Great value in all their 3G kits that are available with everything you need from the electronics, new Align head & blade holders, hardware, and even the little mount to use for pitch angle settings is included. No surprises and nothing else to get - a true plug & play system that is very cost effective.
The 3G may not be the best electronic flybar system on the market for the advanced hardcore 3D pilot, but for general, scale, sport, and average 3D'er flying styles, the 3G system offers so much for so little! I have been so happy with mine in the 600&700 but it doesn't end there...
Align also has the 3GX flybarless system which has raised the bar big time. I've been flying a Trex 600E Pro and 800E Trekker with the 3GX and it's superb! Fully customizable feel, support of all swash mixing types, piro compensation, integrated governor, full integration of both Spektrum/JR & Futaba S-Bus support (the unit essentially becomes your servo hub) - yep, bet you're glad you went with a big name radio brand now. The 3GX also has a GPS based auto pilot system (APS) that is used with the 3GX for pin point hands off hovering, way point set flights, and even a return to home and land feature if your radio system fails or you go out of range. Smart phone and tablet connectivity is also being talked about for at the field programming and adjustment. I'll never get bored of this hobby!
Being a Canadian boy and living in BC, I have to mention the folks at Skookum Robotics located in Vancouver. I love it when a small Canadian company can go head to head with some of the big players and come out with both a high quality electronic product that gets great reviews and is priced competitively.
The SK-720 like most of the flybarless units is a stand alone electronic system (you will need to get your flybarless rotor head and hardware separately). The SK-720 does require a PC/laptop hookup for setup and programming, but they also offer a small hand held data terminal for field programming.
The SK-720 has some really neat features such as flight log recording and a future GPS accessory perhaps enabling an "auto pilot" add on?
Futaba claim their CGY750 is the Most Advanced Flybarless System going. Like the Align 3GX, it's lightweight with governor included. Futaba's CGY750 is modeled after the highly successful GY701 heading lock gyro, but of course with two more gyros to detect pitch and roll.
The CGY750 uses the same large, easy-to-read display as the GY701 tail gyro and is just as easy to setup using the display as the visual interface to see exactly what you're doing and what values you're setting. This along the basic and expert menus helps for hassle free setup. This is what I like about the Futaba GGY750 flybarless system - no PC interface required during the setup, just like Align's.
MSH out of Italy is one of the newest and most sought after flybarless stabilization units on the market right now being both Spektrum DSM2/X remote receiver compatible as well as Futaba S-Bus compatible. It is highly praised by Bert Kammerer as one of the best feeling and reacting flybarless systems on the market right now. As mentioned earlier, is has a neat "right-side-up" rescue feature if you get into trouble while inverted and become disoriented, the unit will bring you back into an upright and level orientation when told to do so, plus the beginner mode to make the heli almost behave like a micro coaxial. Bert has an excellent video I have at the bottom of the page with all the other FBL videos where he talks about not only the MSH Brain, but what he looks for in any FBL system. Even if the Brain is not on your radar scope, have a peek at the video - lots of good stuff in there if you are trying to understand flybarless. The MSH Brain is also being marketed as the iKON - the Brain is in a black case, the iKON is in a red case.
HeliCommand actually has three different types of systems. The Rigid is part of their M-Series. The P-Series is their professional stabilization system with auto pilot that costs thousands of dollars and is intended for high end AP (aerial photography/video) applications.
Their newer X-series is a pure flybarless system with no optical stabilization and has been specifically developed for scale right up to very aggressive 3D type flying supporting all swash types and multi bladed heads for the scale crowd.
The HC-3Base, HC-3X & HC-3SX) range in price from about $275.00 USD for the base version up to about $550.00 for the SX. The units are encased in a strong aluminum shell, use the latest generation MEMS gyro technology, plus every bit (more so in fact) as customizable as the original Rigid but easier to configure. With flight logging (SX version) and full firmware updatability online download support, the X series are indeed an impressive choice.
One of the neatest new features the SX version supports is something called "Rescue Mode". Basically no matter what position your bird is in, when you hit whatever toggle on your TX that you assigned to engage rescue mode, the heli will come back into a level & horizontal attitude and gain altitude. For those of us practicing aerobatics and getting comfortable with all the orientation reversals that occur when inverted or just simply getting disoriented, this feature alone has me wanting one and may be the final solution to end my simulator boredom! The SX also supports both Spektrum/JR & Futaba S-Bus once again showing which direction this technology is headed as well as the ever growing importance of staying with one of 3 big radio brands when getting into these more advanced flybarless systems.
The Mikado VBar and mini Vbar flybarless systems out of Germany are also very popular and very performance minded. Some feel they are the best flybarless system out there, or at least used to be before some of the newest offerings from Align 3GX with latest firmware, Futaba, HeliCommand, and MHS were released.
There is no doubt the VBar will continue to be a popular choice because, just as with most of these systems, the software keeps getting tweaked and allows so much setup flexibility. Once again, the 3 big name radio manufacturers are fully supported with the Mikado V-Bar systems acting as your RX being both Futaba S-Bus friendly as well as Spektrum & JR DSM2/X satellite receiver friendly.
The MicroBeast by BeastX (again out of Germany) is another FBL system many are raving about. Basically unheard of not long ago, they are now going head to head with the big names and cleaning house.
Fully Spektrum/JR DSM2/X remote RX and Futaba S-Bus compatible in a single contained unit - again showing the direction this technology is heading.
The one neat feature that is particularly appealing for some with the MicroBeast is all the electronic swash mixing is done internally by the system making eCCPM swash setup much simpler with this flybarless unit over others. I personally feel it is one of the best stabilization units for people's first introduction into virtual flybars due to it's out of the bag plug and play simplicity. The MicroBeast works equally well on tiny electric 250's all the way up to large 90 size nitros.
Spektrum have also teamed up with BeastX (or maybe it was the other way around) and are offering their
7 channel receiver which is essentially a 7 channel DSMX Spektrum receiver with the MicroBeast system built in with provision for one addition remote Spektrum RX.
For about $240.00USD, this is a good value option if you fly with a Spektrum or JR DSM/X radio and want to get a combination RX and Flybarless stabilization unit to save a little money over getting two separate components not to mention make for a cleaner and simplified install.
As you can see, the continuing trend and holy grail of flybarless stabilization right now is to create systems that respond with the predictability and consistency of a flybar, yet give that "tracking on rails" flight experience. Ease of setup is another big direction push with all these systems and their subsequent firmware updates.
To conclude, I will leave you with 4 flybarless videos. First is a really excellent explanation by Bert Kammerer of what he looks for in a flybarless system using the MSH Brain as his weapon of choice.
Next up is Bobby Watts going over some of the features of Futaba's CGY750 along with a flight demo.
Third we have Alan Szabo putting both the Trex 600E Pro and the Align 3GX through the paces.
Here is the HeliCommand HC-3SX showing the "rescue mode" in operation...
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