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Heli Command - HC3-SX Flybarless Gyro Review


Dimensions:36mm x 34mm x 14mm
Supply Voltage:4 - 10V
Max Roll/Pitch Speed:500°/s
Max Tail Speed:650°/s (typical)
Servo Frame Rate:55Hz/220Hz selectable
Tail Servo Output:1,52ms/0,76ms selectable
Maximum Servo Currents:10A (continuous load)
Weight:18 grams
Available From:Esprit Model

There are a lot of flybarless gyros on the market right now, but only a select few have the ability to level the helicopter back to upright with the flip of a switch. What would you use this for? The first thing that comes to mind is to bail yourself out of trouble while trying a new maneuver, or if you find yourself in an orientation you aren’t used to. Another thing it could do is instill a little more confidence into your flight, like you know you can fly a particular maneuver but have been afraid to try it for real. This is where the HC3-SX from HeliCommand really proves its worth. With the flick of a switch your heli will automatically level out and start climbing up into the sky, giving you a chance to get your bearings and carry on the flight. However the HC3-SX does more. Aside from being a powerful flybarless gyro, you can also set it into what I am going to call a “coax” mode, where the heli will return itself to neutral when you let go of the sticks (kind of like an actual coax heli). The applications are numerous, from 3D helis to scale ships, but for the purpose of this review, I’ll be using a Goblin 700.

In The Box

The HC3-SX comes in a small tin; with the gyro sitting in custom cut foam padding. Also in the tin is the USB interface, adhesive mounting pads, USB flash drive with programming software and instruction manual loaded, wiring loom, and a decal sheet.

The gyro is small and light, weighing in at just .63 ounces. It’s housed in a very nice durable aluminum case. There are nine plugs lined up in a row, with a tenth two pin plug in the center. The two pin plug is used only by part of the loom plug (for attaching to a standard receiver, see further down). On each side of the gyro is a plug used for Spektrum satellite receivers, and it is worth noting that the HC3-SX is also S.Bus compatible. A large, highly visible LED is on the top of gyro toward the corner. Another point worth noting is that the company that makes the HC3-SX, Captron, is a leading sensor switch and PCB assembly and manufacturing company. I don’t think we could have a more suited company to make the HC3-SX.

Another unique feature about the self leveling part of the HC3-SX, is that it does not have any accelerometers in it. Traditionally, this is what companies use for self leveling technology, however accelerometers are prone to vibrations, making it absolutely necessary to tune out any and all vibration from your helicopter (or get them down to an acceptable level for the gyro). With the HC3-SX, it is no accelerometers, no vibration, no fuss. The way it actually works is something of a trade secret, and almost seems adaptive as you can retrain the gyro in flight as to where the horizon is (by just hovering around for a bit).


Mounting the gyro is straight forward, but I was warned to discard the thicker of the mounting tape to avoid setup problems. It seems that the gyro likes to be as rigid to the helicopter as possible, and any movement of the gyro from the helicopter will cause problems. If you are using S.Bus (as I did), you connect the one wire from your receiver to the HC3-SX, and then connect your battery and servos directly into the gyro. As mentioned before, Spektrum users can plug a satellite receiver directly into the side of the gyro. Anyone else will have to use the supplied loom to connect the gyro to your receiver. All of this is explained in the programming software and instruction manual, so let’s take a look at the actual software.

Regarding the self adhesive foam tape supplied for mounting the gyro. It is recommended that you use the thin tape for electrics, and the thick tape for nitro/gas. My buddy Bob happened to be setting up the HC3-SX in his Synergy N5c while I was doing this review. The N5c is a nitro powered 50 size heli, so he used the recommended thick tape to begin with. The first few times we tried to spool up, the heli showed a tendency to want to tip fairly drastically. After a little trouble shooting, we remounted the gyro using the thin tape, and then everything worked exactly the way it should. Something to bear in mind when you are first testing your setup.


The supplied USB flash drive contains the instruction manual and programming software (also available via download at www.helicommand.com). The gyro is simple to set up, but the software could seem a little overwhelming to someone new to flybarless. The nice thing is that if you are unsure of an item, you can move your mouse over it and a pop up will explain what it is for. For setup purposes, there is also a wizard that will guide you through the initial setup process, making it even easier. The USB adapter simply connects to your computer, and plugs in the first port of the gyro’s servo plugs.

The First Tab – “All”
The first tab of the software, labeled “All”, is what you are presented with when you first load up the program. From here you can check for firmware updates, start the setup wizard, and backup or load your settings. It shows you on the lower right if you are connected to your gyro or not, and your gyro must be powered up to connect. One thing to be aware of when loading files, is that when you do it from the “all” tab, it will load the settings for all of the tabs. However, if you pick one of the tabs, such as “tail” and then load the settings, it will only load and write/change the settings for that particular tab. So from this screen we can start the setup wizard. With a new gyro, you won’t actually be able to view some of the other tabs until you do go through the wizard.

Tab 1 – “RC”
The second tab is used for setting your servo types, and assigning channels. This is also where you select the interface type between your gyro and receiver. Here you can set which channel relates to specific functions. I should also point out that the green equals sign “=” between the read and write buttons indicate that the software and gyro are synced. Before moving to the next tab, it is important to hit the write button to sync them up. That green equals sign will turn red when they are out of sync. Here you can see that my tail gyro gain is set to one channel, while the head gain is set to another. The head gain is an overall setting that can be adjusted from your transmitter while flight testing and setting up your heli. I assigned this channel to a slider switch on my 8FGS so that I could adjust it easily. Once you have found your gain setting, this channel then gets assigned to the rescue feature (more about that further down).

Tab 2 – “Diagnose”
The diagnose screen is great for, well, diagnosing :) . Here you have a visual representation of how the gyro is interpreting the commands you are giving it with your transmitter. It is also a crucial part of setup. Using servo reverse, endpoints, and subtrim on your transmitter, you must make sure that the channel is centered where it should be (using the bars for each channel), and that the endpoints are set to full travel, as well as checking to see that everything is moving in the right direction. Each function shows a bar with a center point and two bars on either side indicating where your endpoints should be set. It’s just a case of looking at the bars and adjusting your transmitter settings so that you get the right amount of travel in both directions. This is a live reading from your gyro, and the only things you are changing are the settings in your transmitter. Therefore there is no need to sync the software with your gyro at this point. Once you have set the endpoints and subtrim on this screen, no more adjustments should be made to the transmitter (except for the gain channels). Off to the left side are visual indications of the signals the gyro is receiving, as well as which mode you are currently in. This is a good time to explain that the term “rigid” used through the software, refers to the normal flybarless operation of the gyro, and the term “horizon” is the self leveling mode.

Tab 3 – “Trim”
This tab is for trimming your servos center point. This is a different operation from the trimming done on the diagnose screen. Subtrimming on the diagnose screen is done with the transmitter, to get all the channels on the diagnose screen centered (the swash is adjusted mechanically afterwards). The trim feature on this tab is used to set where the servo center points are. You shouldn’t be using the transmitter to adjust the servos at this point. Once these steps are completed, you can mechanically adjust your links to level your swash at mid stick/zero degrees pitch.

Tab 4 – “Mixer”
The mixer screen is the main area for setting swash type and servo directions. The HC3-SX is very versatile when it comes to mounting, it can be inverted, vertical, facing any direction. The swash type is set here, with five different options. For the Goblin, it was Tri (120) degrees. Down the left hand side are the options for reversing servos, as well as cyclic direction. Next to the cyclic direction reverse are the travel sliders for setting how much pitch you want on your cyclic (you’ll need a pitch gauge on your blades for this). Continuing to the right is the slider for collective pitch range, again you’ll need your pitch gauge.

I didn’t adjust the cyclic phase (swash rotation for some multi-blade heads), sinus linearizer (what a name! Works against mechanical stress on H4 linkages), or collective offset (which you can't use when using rescue mode with pitch). I’m not entirely sure what the first two do exactly, so I left them alone. Don’t forget to hit the write button!

Tab 5 – “Tail Gyro”
This is where the usual tail setup happens. There are some presets that you can click to get the settings close to some of the popular gyros, or you can customize it from scratch. This is also where you set the trail servo travel limits to prevent the pushrod binding. For optimum performance, it is recommended to set the tail mechanically so that the tail blades sit at zero degrees pitch with the stick in the center position.

Tab 6 – “Rigid”
Rigid, or just flybarless, is where you fine tune the flybarless controller. When the head gain is assigned to an auxiliary channel, your transmitter settings will override the head gyro gain default shown at the top of this screen. Once you’ve test flown and found a head gain setting that you like, you find out what that value is on the diagnose screen before reassigning your aux switch to bailout mode, and input that value on this page. You can also adjust the elevator and aileron gains individually. Agility sets how fast the helicopter responds, and there are a few more options here that you can tweak to suit your model (including P and D gains).

Tab 7 – “Horizon”
The first option on this tab is what to assign your auxiliary channel to. Rigid gain refers to the overall head gain, which is what you want to start with when dialing in your heli during initial flights. Once you have that setting (as discussed under tab 6) you can then switch your aux channel over to horizon mode, which is the self leveling mode. The type of model you are flying and the results you want from activating horizon mode will dictate your settings here. For me, I wanted to be able to fly 3D with the gyro set to rigid (which is regular flybarless mode), and use a momentary switch on my 8FGS to activate horizon mode (self leveling). I chose the acro mode under 3D mode so that when activate my model will either level to upright or inverted (whichever is quicker) and start climbing. The second option “goes to pos” will always turn the model to the upright position before climbing, which is something you may choose to do if you are learning inverted flight.

The self leveling modes on the left are basically the modes to use on a general sport or scale model (i.e. not 3D flying), using self level only, either as soon as you let go of the sticks, much like a coax heli, or by flicking a switch when needed. This would be a good option to choose for a scale helicopter, or if you are starting to learn forward flight. The two options for this give you the ability to either always level to upright, or both to upright and vertical depending on which is closer (much like 3D mode).

The only option I changed in the advanced menus was the “coll. pitch travel only for rescue action”. Reducing this slowed down the rate at which the helicopter climbs when rescue mode is activated (which by default on the Goblin was like a rocket ship!).

“Real Time Tuning” Tab
This tab allows you two assign your aux channel to any number of different functions for fine tuning without a computer.

“Help” Tab
As the name suggest, this is where all the help files and info are stored. There are even some neat diagrams showing you how to wire your setup.

Setup and Flying

After doing a thorough preflight check, and making sure that everything was moving in the correct direction, and that the gyros were responding correctly, I set my head gain at about 50% gain and took off. As a side note, 20% head gain is the minimum at the center midpoint of your channel. Either side of the midpoint increases gain up to 100% at either extreme. Therefore, to get 50% gain, I set my slider at ¾ of total travel, knowing that I could bump it up gradually as needed. Once in the air, I hovered for a few seconds, landed, bumped up the gain, and took off. By progressing through various stages of flight, I was able to get the head gain where I wanted it, which was just a little below where the shakes wanted to start. Now, I confess that I did cheat a little and had a file from a fellow Goblin flier who also uses the HC3-SX, but I did still have to dial in my head gain as though I was starting from scratch. I adjusted the aileron gain separately from the elevator via a laptop (which is a handy thing to have at the field during the setup phase) and also played around with the agility slider until I found a setting I liked.

I flew several flights before even setting up the horizon mode (bail out mode), mainly because the Goblin was flying so good that I forgot that I had another step to complete. The HC3-SX flies extremely well, it is smooth and locked in, and I was having a great time with the Goblin. I was very impressed with the gyro, it felt great and didn’t do anything strange. I had a small aileron wobble when doing tail down tic tocs, which is why I reduced the aileron gain as mentioned above. Other than that, the Goblin was in great shape!

After checking the diagnose screen and reading my head gain setting (which was at 80%), I input that value into the Rigid tab, and assigned my aux channel to Horizon under the Horizon tab. There are two ways that you can check the horizon mode is functioning correctly. The status LED on the gyro is normally amber in color, when horizon mode is enabled (rescue) it flashes green. The second way is to look at the diagnose tab and check that the Hor. Channel is moving in the correct direction. This will also be indicated in the stabilization window on the left.

Once Horizon mode is assigned, it is important to initialize the heli on a level surface and to keep movement down to a minimum before takeoff. I first flew the Goblin around to check that all was still good, then I leveled out manually and hit the “rescue” switch to activate horizon mode. The Goblin straightened itself out and shot up skyward like a ballistic missile! So as I mentioned earlier, I dialed it down to a more manageable setting and tried again. This gave a much better response, it still righted itself extremely quickly and climbed vertically at a moderate rate. I then flew several flights and put the Goblin in many different positions and experimented with my new rescue feature. Each time the Goblin would right itself (either upright or inverted) and shoot skyward.

The first video below is just a regular flight, trying out the HC3-SX as a gyro. The second video illustrates the rescue mode.

Youtube Link

Youtube Link

Only one time did I have an issue, and I only had myself to blame. I hit the rescue switch at the beginning of a flight, and the Goblin shot up and to the side at a 45 degree angle. Remember I said it needed to be kept still during initialization? Well this is what happens when you don’t. I later learned that the gyro is constantly calculating the horizon and that if I had let the helicopter hover for a few seconds it would have adapted, and gotten over the fact that I didn’t exactly keep it still when I plugged it in.


Rescue features aside, the HC3-SX as a flybarless gyro is outstanding by itself. If you find yourself without the need for the rescue feature, you can purchase the HC3-Xtreme version (which has a new lower price as of November) and have all the same programmability, just without the self level feature. As a gyro I am impressed, combine the fact that firmware updates can be done by the end user (me!) and they really have a winner on their hands. I know some of you will be looking at the price of the HC3-SX thinking it is a little pricey, but put it against some of the best gyros out there and then ask yourself what a single crash or more would cost. Don’t be fooled by its humble beginnings either, this is a serious gyro that can be used pro pilots and beginners alike. For beginners, or sport pilots learning to 3D, or even 3D guys trying something new, I am sure that the rescue feature will save you some pennies by avoiding possible crashes. Even forgetting parts cost on a crash rebuild, this is worth it to me in the time it will save from having to rebuild and go through the setup process all over again.

Pros: Cons:
Awesome performance Sensitive to movement on startup
Easy setup Need a laptop to program
Great customer service

Will save you from crashing!

#2 Reco Nov 07, 2012 05:21 PM

A I missing something? This seems a little exspensive when you take into consideration the FBL setups availabke at hobby king and such... Regardless great review very detailed.

#3 eRaptor Nov 07, 2012 08:03 PM

As Chris said, it is a combination of service, performance and reliability that is hard to beat. It is well worth the price the first time Capt Rescue helps you out.

And the Helicommand people are always very helpful on several forums.

#4 DismayingObservation Nov 08, 2012 01:06 AM

Reco, I'd do a HobbyKing FBL setup on a clone, but no way would I want anything less than something this sophistcated on a high-dollar ride like a Goblin 700.

If anyone is going to drop five bills on this system, it's definitely going on a pricey machine.

#5 Reco Nov 08, 2012 06:45 AM


Originally Posted by DismayingObservation (Post 23213647)
Reco, I'd do a HobbyKing FBL setup on a clone, but no way would I want anything less than something this sophistcated on a high-dollar ride like a Goblin 700.

If anyone is going to drop five bills on this system, it's definitely going on a pricey machine.

I undestand I just get snow blind to using cheap chinese knock offs lol. But I guess thats the whole problem here anyway, we are all drunk on chinese crap.

#6 everydayflyer Nov 08, 2012 06:51 AM

I have three 450 class helis with $50 - $70 FBL units which work really well IMO. My Blade400 FBL is so much better than it ever was with a FB and it is so much easier,faster to repaire after a dumb thumbs event.

I have read many post about the Beast X ,Ikon and other FBL units with self leveling which according to most do not work very well. It sounds like HC got it correct with this unit and man the Bail Out /Rescue save my bacon switch could / would likely save me a lot of rebuilds and down time.


If anyone is going to drop five bills on this system, it's definitely going on a pricey machine.
For most this is likely true but there are some of us who really want a save my bird ability. Twenty some odd years ago I taught myself to setup ,trim , fly a Concept 30 and advanced to a Kalt Cyclone 50. Work and life got in the way and I went back to flying planks as I rarely crash one of these.

Four years ago I purchased a Blade 400 and averaged about 10 flights between crashes and after 8 or 10 crashes shelfed it for three years. This spring I started helis again this time with a mCPX then added a BL one and converted the first one to BL and a few months later added a Blade 130X. THese Micros advanced my heli abilities big time so about two months ago converted Blade 400 to FBL and while flying is much better than ever before I still make mistakes that result in rebuilds which can run into money. I did manage a string of just over 50 flights between my B400 and a B450 which is a personal best for me .Last dumb thumbs event main shaft,feathering shaft, main drive gear,tail shaft, several bearings,new frame ,landing gear and set of CF blades plus around 10 hours of rebuild / setup time.

I know ,practice new manuvers with the mCPXs and 130X and use a flight Sim. I agree and as mentioned micros have helped big time but still not the same as a 450 ,biggest difference is knowing the 450 will require rebuilding after it goes in.


#7 everydayflyer Nov 08, 2012 09:11 AM

Chris two simple questions.

Can the rescue mode be set to always go to upright even if heli is inverted or closer to level inverted?

Will the rescue override any stick positions at time it is engaged or does one have to also center / relax the cyclic stick?


#8 CSpaced Nov 08, 2012 09:14 AM


Originally Posted by everydayflyer (Post 23214671)
Last dumb thumbs event main shaft,feathering shaft, main drive gear,tail shaft, several bearings,new frame ,landing gear and set of CF blades plus around 10 hours of rebuild / setup time.

This is the kind of thing I'm talking about. I spend a lot of time getting my helis set up perfectly, and it kills me that I have to go through it again after a crash to get back to that perfect setup.

You know how it is. First you shelve the heli for a few days 'cause you can't bear to look at it :D, then you meticulously take it apart to identify the damaged parts. Order the parts online, or get your LHS to order them. You get the parts and rebuild it, and then you go through the setup all over again.

Or, you flip a switch when you start getting into trouble, take a few breaths and unclench while your heli cruises skywards, and then rock on all over again.

#9 CSpaced Nov 08, 2012 09:18 AM


Originally Posted by everydayflyer (Post 23215532)
Chris two simple questions.

Can the rescue mode be set to always go to upright even if heli is inverted or closer to level inverted?

Will the rescue override any stick positions at time it is engaged or does one have to also center / relax the cyclic stick?


First question, yes. You can set it so that it will always go to upright.

You can let go of the sticks while holding the rescue switch (which I do in the video above). Once you release the switch, the heli will jump to where ever your sticks are, so there may be a little jump when you let go of the switch. I got in the habit of centering the sticks before letting go of the switch.

Also, the HC doesn't have any control over the throttle channel, so don't try flipping upside down in normal mode and then hitting the switch :D

#10 Seasick78 Nov 08, 2012 11:53 AM


Originally Posted by everydayflyer (Post 23215532)
Chris two simple questions.

Can the rescue mode be set to always go to upright even if heli is inverted or closer to level inverted?

Will the rescue override any stick positions at time it is engaged or does one have to also center / relax the cyclic stick?


To add to what Chris said about this above...

I use the momentary switch for rescue (as in his video) on my 8FG and Goblin 630. For the Horizon mode (coaxial, as Chris described it), I use a 3 position switch. In the up position it is off. In the middle it is 17%, when down it is 40%. For horizon mode you do not have to hold the switch. You can turn it on and fly the model around. Let go of the cyclic and it will level the heli. The value stated above (17% & 40%) can be considered to be the intensity of the self level feature. This has nothing to do with rescue... Only self level aka horizon aka coaxial mode.

The lower the value, the less the system will work against you in flight. That is, if you set it to 50% it'll be so much like a coaxial that it may feel hard to fly because it constantly wants to level the heli. Around 17% though, you have complete control in flight and can still have the self level feature work when you let go of the cyclic.

This is the same whether upright or inverted if you have the unit programmed to function that way (its user defined!).

I set bailout/rescue to a momentary switch so I don't have to remember to turn it off after safely rescuing. Don't want to let it get away from me when activated, so, a momentary switch allows you to just let go of the switch to deactivate rescue.

Hope that helps add a little more clarity. :)

- Josh

#11 everydayflyer Nov 08, 2012 03:45 PM

Thanks gentelmen that clears up my questions , now left with the is it worth $500 or not. Logic says yes however the way my luck runs if I purchase one now in a few months there will be $300 versions of it on the market but then they will not have such a great proven track record either.


#12 Seasick78 Nov 08, 2012 04:14 PM


Originally Posted by everydayflyer (Post 23218771)
Thanks gentelmen that clears up my questions , now left with the is it worth $500 or not. Logic says yes however the way my luck runs if I purchase one now in a few months there will be $300 versions of it on the market but then they will not have such a great proven track record either.


This unit has been available for a few years now. The price just officially dropped from $550+ to $499 just this month. Other systems have self level features that work every now and then. You can research for yourself, this one works reliably PLUS has the rescue feature that is fully customizable.

As it is often said - You get what you pay for. ;)

#13 GetToDaChopper Nov 09, 2012 02:07 AM

The HC3-SX simply has the BEST self leveling in the biz and it's in a league of it's own !!! i don't know how it does it but just hit that switch and it works EVERY time without fail !!!

Oh and it's a great FBL contoller to to boot with one of the better tails, right up there with a V-Bar...... ;)

#14 Watdazit Nov 12, 2012 12:54 AM

It's paid for itself already. There is only a couple of things I would ask for and both I have suggested to Helicommand and they have taken them on board. It's nice to find a manufacturer who listens.
(1) The connections on the top are a pain IMHO and they should be on the side.
(2) The manual and computer setup guide need some work so they can be understood better.

I also have HC 3D's and find the HC3SX tail gyro heaps better than the 3D.

I use a BeastX on an Atom 500 and whilst it is a good unit I would swap it for an HC3SX if I could find somewhere to fit it. If it has side connections I would buy another one tomorrow. I have a 3G on a scale and again it works but the HC3SX is in a class of it's own.

Someone mention Hobby King. I have never and would never use any of their electronics on my helis. They are OK for a $150 foamy or ply and balsa plank but not a $1750 heli.

#15 Elios000 Nov 22, 2012 05:47 PM

HK fbl clones are no where in the league of this and others like the SK720, Brain, BeastX and V-Bar
and imo the V-Bar is the best FBL controller you can buy if you dont need the auto leveling

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