Last edited: Sep 14, If done right it's safe. As a matter of fact, I do have some experience with doing it in RL. That is why I know something about it and spoke up. I guess I am rather uptight about helis after that accident. Please don't fly that around anyone. There really is no need to do that. And simulating it? A lot of effort for little gain. My understanding right now is that if done right and carefully it's a LOT safer than a lot of things I have been seeing done at fun-flys and such.
With that I'll mention that I don't fly anything bigger than a to date and when I have been trying anything experimental I wear a hard hat and extra eye protection. Brianappjj Member. Some people do fly nobar with success. I would like to try it as well but on a simulator first. That is why it is called a simulator. It lets you simulate things before actually trying them. Kind of what it is for. Zelatio New member. That looks like such a handful and unstable and dangerous. Seems dumb to me.
N8LBV said:. Zelatio said:. I didn't see much unsafe there. He obviously didn't watch the entire video! Really actually I could have executed a similar flight path. Especially in no or little wind. I would never fly it close to people or right in that kid's face and hover 1" above the kid's head like that guy was doing.
I was flying in mph wind varying in the video. With the flybar it would also get bopped around a bit in the wind like that as well. At no point was it unpredictable or out of control. I did slam on the collective full bore once and jam the cyclic to it's extents a couple of times quickly just to see how it responded. It was extremely responsive and it pitches up or down in FFF but it does it predictably and you can account for it.
It was never spastic doign things on it's own or random. I feel Nobar is an experience and design thing as far as safety goes. So is collective pitch flybarred flying. It's safe if done safely. Aside from that we can argue whether or not my flight in the video was safe or not.
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.
The same cyclic pitch changes that the mechanical flybar would impart to the main rotor blades are now done by the two head 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. This is such a common question for those new to flybarless or just starting out in the hobby. Just like a standard tail gyro, most stand-alone flybarless control systems ie.
The servos that control your helicopter pitch, yaw, roll, collective are then connected to the FBL system so it can move those servos as required to both stabilize the helicopter and impart your desired movement commands. Pictured above is a typical standard RX wiring connection. This is the most common FBL connectivity method and is support by most flybarless units. The RX communicates with the FBL unit through this multi conductor wiring harness using the same standard PWM pulse width modulation signal that it uses to communicate with servos PWM is covered in detail on my servo page.
Each individual control channel output from the RX is connected to the FBL input for that same control function. An example would be Aileron-out on the RX to Aileron-in on the FBL unit and so on for elevator, rudder, collective, gain, and perhaps throttle.
The main drawback is it's bulky requiring a full function larger RX along with a mass of wiring. The advantage is it's a very simple and elegant connection method, with very little weight or bulk. The downside can be if you need more channels such as in scale , you don't have them since most FBL units don't have more than one or two extra channel outputs if any. Telemetry lack there of is also a problem if you use telemetry. Last up we have S. The big advantage here is much more data can be transferred and in both directions.
This is getting to be the primary method many higher end FBL systems and serious pilots are utilizing since it's compact, light, elegant and powerful. If you're curious how the FBL system knows which RX connection method is used, it's a setting that you have to choose while setting up your FBL system pictured in the yellow box above. One of the most frequently asked e-mail FBL questions I get is "how does it feel or fly compared to a flybar". 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.
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. Hovering is less dramatic of a "change in feel". If you have the cyclic gains 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 in a hover as a flybar, but do require a little 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.
Honestly, with a larger heli anyways , hovering either flybar or flybarless feels very similar and there is not too much difference in the feel. I know I have had some perfectly setup and trimmed out flybared machines over the years that could hold a hands off hover for up to 10 seconds in zero wind conditions which is just as good or even better than any FBL heli I currently own. Anyone who tells you a flybar heli is not as stable in a hover, simply has never experienced flying a top-end flybared machine.
Again, that applies to larger RC helicotpers say and up and in zero wind conditions. The smaller the heli and the windier it is, the more FBL systems help stabilize the hover - no question. As I was just mentioning — performance is a big one! For electric power, this also equates to slightly longer flight times. Overall flight speed is also up 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. You are basically eliminating not only the flybar and paddles, but also the flybar mixing cage assembly, associated bearings, 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 and added mechanical complexity when compared to a flybarless rotor head. Flybars also tend to eat up tail booms and canopies in most respectable crashes. Tiny micro collective pitch helis like the Blade Nano or Trex X , are only possible because of their FBL electronic stabilization systems.
It's also doubtful the flybar could react fast enough on micro CP helicopters due to the very high head speeds they run at and low fly-bar mass, resulting at minimum in horrible toilet bowl effect. Moreover, some systems feature a h orizon mode or self-leveling mode that can make a collective pitch heli behave somewhat like a stable coaxial or quad rotor, while not allowing it to pitch or roll past a certain angle.
Besides helping beginners, these features can save the heli while practicing aerobatics or 3D when things go sideways and the poo-poo is about to hit the fan. This multi sensor system is correctly known as an IMU internal measurement unit.
You will unfortunately often see them marketed as 6 or 9 axis gyros which is nothing more than marketing wank and complete nonsense!
We do after all live in a 3 dimensional universe, and it's impossible to detect more than 3 axis of physical spacial movement along the yaw, pitch, and roll axis. The correct term they should be marketed by is 6 or 9 axis sensors or IMU's not gyros.
The 6 axis IMU will use a standard 3 axis gyro in combination with a 3 axis accelerometer. The gyro sensors detect rotational movement around each axis, while the accelerometer sensors can reference both acceleration and gravity pull around each axis to further stabilize the heli and level it out in a bail out or save activation.
Drifting still will occur however as error rates build over time. The 9 axis IMU as pictured above adds in three magnetometer sensors on each axis which reference magnetic fields to help with the time induced drifting problem.
Problem is, all those additional sensors require a good deal more processing power as the algorithms become much more complicated; so there are trade offs to number of sensors, performance, and of course costs. I highly recommend beginners never attempt to setup these rescue modes unless you have an experienced RC heli pilot to help you. Cost is the biggest one talking regular size birds here, not micros , but the differences in prices are coming down all the time.
You will however need good high quality, high speed, and high torque digital servos for most FBL systems. 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. In addition to that, the servos are not only working harder, they are also working more. They are now responsible for all the little movement corrections to stabilize the helicopter that the flybar used to do.
You really notice this extra work load on micro helicopters that use linear servos. This is also why long lived brushless digital servos are now becoming very popular with many RC heli hobbyists as they are very well suited to the high FBL workload on larger RC helicopters anyways.
Setup can and usually is more complicated on a flybarless heli when compared to a flybared one. I used it in my Bergen Intrepid turbine helicopter and it was a nightmare to setup correctly for my first introduction to FBL. It literally took me months of experimenting to get it where I somewhat liked how it responded and felt.
Thankfully, the setup wizards have improved a great deal over the past decade and are getting easier to configure and use. Factory out of the box settings are also generally much better now as well, and you may not even have to mess with them. This was my main concern with electronic stabilization. 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.
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