Align 3G Flybarless - V1 interim review
Written by Ashley Davis Wednesday, 05 May 2010 19:24
Align 3GThe following is an interim review of the Align 3G Flybarless conversion kit for the T-Rex 600.
I will complete the full review once V2 of the software is released and the programming box is available and has been tested. This review comes across as just a few flights but it is actually the condensed version of several weeks of testing.
Thanks to Align UK and Skyline Models for sponsoring this and supplying the 3G Flybarless System.
Introduction
I am sure that most people will have noticed that this year appears to be the year that flybarless systems look set to become far more popular. There are many new systems coming onto the market and the Align system is probably the most popular currently. This article is an interim review of my experiences so far with the Align 3G system.
I have made a video of my experiences installing the Align 3G system and this will be appearing on the site as soon as I've finished editing it. An overview of the system can be found here.
Configuring the system
There have been several videos showing how to configure the Align system (I quite like Bert Kammerers video) . Certainly in my experience of four different mainstream systems the Align system is very straightforward and requires minimal reading of the documentation in order to configure it successfully. All of the programming of the Align flybarless system is achieved through moving the transmitter sticks at the appropriate time and pressing a button on the unit itself. Additionally there are two pots on the programming unit which can be turned to adjust the amount of elevator and aileron gain.
Whilst this very simplistic programming approach may suit those who aren't prepared to read a manual or understand the complex parameters involved in configuring a flybarless system it does prohibit the amount of configuration you can do on the Align system.
I will come back to this later, but this in my opinion is actually more of a loss than a gain when trying to get the most out of the Align flybarless system.
The test bed
The helicopter I chose to use as the test bed is my very own T-Rex 600N. This machine is fitted with a OS50 hyper and uses JR 8717 servos. The servos were specifically chosen as this machine was to be used for flybarless testing. I wanted to make sure I had the fastest and most accurate servos available so that any problems were a symptom of the flybarless system and not the servos. The helicopter is also fitted with a CSM revlock 30 and the tail servo is an Align DS 620. I am using SAB 95 mm tail blades and have a variety of main blades to try.
Flight testing
Initially I fitted my machine with very light stick banger blades (YuYu design blades). The elevator and aileron gain pots were set to about 11 o'clock which seems to be a starting default for most people. Lifting off into the hover the model had a very pronounced elevator nod. No amount of adjusting the gain pots would allow me to get rid of this elevator nod. I ended up with the gain so low that the helicopter felt very unstable. At this point I looked into vibration as a possible cause of my problems and found the front gyro mount to be very poor for vibrations, so the sensor was moved to the back of the machine on the boom clamp. Rob Turnbull also advised that he had had good success with this relocation of the sensor and had lost much of his machines nodding from making this change.
Given that stick banger blades are probably the worst kind of blades to try to use with a flybarless system I decided to go to the other end of the spectrum and fit a set of old SAB carbon blades. These blades are about five years old and I have always considered them quite a stable blade. Lifting off into the hover there was a pronounced difference and the elevator nod was almost but not quite gone. I had a little tweak of the gain pots and got the whole thing to a point where the elevator nod was only visible in manoeuvres like a funnel or pie dish. At this point I was pretty happy with the cyclic response of the helicopter so now it was time to work on the tail system.
I had noticed that in every flight the tail had seemed to have a high frequency wag. Adjusting the gain via the transmitter did not appear to have any effect on this wagging. Once again I ended up with the gain so low that the tail wasn't holding properly and finally accepted that I was going to have to put up with this high frequency wag. I was considering at this point using different mounting tapes for the gyro sensor but collective feedback on the forums appeared to indicate that this would not work. Having accepted this slightly nervous high frequency wag I set about testing the holding capability of the tail. Despite the wagging the tail holds very well and at no point did I feel it was going to let go or misbehave. Let's chalk that up as a good point.
Moving onto pirouetting manoeuvres I had a serious surprise in store. When doing a pirouetting wall of death the tail was pirouetting like a second hand on a clock. It was jerking round in fixed steps making it almost impossible to get the stick stir in time with the motion of the tail. Not long after this the tail did an un-commanded quarter pirouette in fast forward flight and then returned the tail to its correct position. This last action was very worrying and I decided that for the sake of my model it may be better to disconnect the tail system and use my own CSM gyro for further testing.
The next flight was using the SAB blades, CSM 720 gyro and the Align 3G flybarless system on the cyclic. This configuration was by far the best I had managed to get the system so far. My gain pots were back at between 10 and 11 o'clock and the whole thing felt very solid in flight. I still had a perceptible elevator nod in certain manoeuvres and I decided to buy some flybarless blades as an attempt to fix this.
The next flight was using Torsion flybarless extreme blades and I was expecting to have lost all signs of elevator nod. I could not have been more wrong! Just by swapping the blades and not changing anything else I now had a pronounced elevator nod and a pronounced aileron nod. In fact this was now the worst the cyclic had ever been and I could see myself once again chasing the aileron and elevator gain pots in order to find the sweet spot for these blades. Once again my experience of chasing gain pots was that if the Align flybarless system doesn't like the blades then there is nothing you can do to change that (at least not yet).
This led me straight back to installing the SAB blades and realising that I was probably going to have to spend a lot of money trying out different blades in order to get rid of elevator nodding entirely. Considering how small my elevator nod was with the SAB blades I decided to just put up with it.... hardly the best result but definitely the cheapest.
As a side test I installed the Torsion blades on the same machine equipped with a V-Bar and they didn't produce any unwanted nodding, confirming my suspicions that this was an idiosyncrasy of the Align flybarless system.
How does it feel
This is an important aspect of the Align system. The cyclic response does not feel wildly different from a flybar. This is different to other systems I have tried which have felt very different to a flybar equipped helicopter. The ony place I notice any difference to a flybar is in big moves where the gyro holds the helicopter perfectly on track (loops and so forth) and in chaos where there feels like there is a slight bit of delay in the stick inputs.
Conclusion
Having discussed the 3G system with other owners it would appear that the T-Rex 600 is one of the more difficult systems to configure. Symptoms of nodding and difficulty with certain types of blades appears to be commonplace. Additionally the high frequency tail wag, stuttering tail in pirouettes and even the un-commanded quarter pirouette in forward flight have been reported by other users. The Align system only provides two gain pots to allow configuration of your flight parameters and this is where I come back to my point at the beginning of this review. The system really needs much more configurability in order to be tuned properly to the vast myriad of different helicopters. When I refer to different helicopters I really just refer to the fact that the same helicopter can be fitted with all kinds of different equipment and different results will be gained. For me by far the best configuration was using a separate tail gyro and the SAB blades. Others may have completely different results depending on what they have installed in their machine.
Align has recently announced Version 2 of its software and a programming box allows configuration of the 3G systems internal parameters. Until these are available I don't feel the Align system is actually a great investment given the problems. Once they are available, configuration of the system is going to be similar in complexity to systems such as the V-Bar...... although I welcome this as I should then be able to resolve my issues.
It would appear that T-Rex 700 owners are the ones having the best success with the Align flybarless system in its current form and hopefully the advent of programming boxes will allow others to achieve the same results. Certainly if the new programmer really does allow nodding, tail wag and weird pirouettes to be resolved then Align may have a winning system. I hope it does fix the problems as so far, despite the issues, it is the most 'like a flybar' flybarless system I have flown.
Interim Verdict - teething problems, may be best to wait for version 2 (due any day now)
( 6 Votes )
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