New Flybarless System

[Skookum]

>Would you have advanced tab 1 and 2?

Something like that ya. Getting the user interface right & testing is what takes the time.

[SpeedVision]

>Would you have advanced tab 1 and 2?

Something like that ya. Getting the user interface right & testing is what takes the time.

Well, since this is a want to have and not a need to have yesterday, we'll sit back, be patient and let you do your magic.:YeaBaby:

[Finless]

I think this would be a GREAT idea... you can tame it down a little and click a switch and have a rockin fast locked in head ;)

Bob


OOps how I explained the idea of an SK360 remote-gain channel still wasn't clear. Let's call the contents of the Advanced Tab a "gain profile", not a mode. Mode = flight mode vs setup mode.

* Yes, you'd need a 7th channel (unless you can run your tail gyro in HH mode without a gain channel for it)
* Flipping the switch for the sk360's remote gain would switch between two "gain profiles", which would be everything on the Advanced Tab in the setup software.
* The travel in each direction of the remote gain channel would have the same function as the "hiller gain dial" on the case of the sk360. So you could set that independently for each profile, at your radio.
* If you changed the hiller-gain at your radio by changing that travel, the sk360 would only read the gain change when you cycled the sk360's switch at your radio (the 4th input can only read a rough value full time or it risks noise at the servo outputs). You could safely change gain-profiles in flight.

Re the usefulness of a rudder input, it's the other way, rudder info wouldn't be very useful to the sk360, but collective info can give the tail a crude heads-up about coming torque changes. This is why the vstabi reportedly has good tail holding ability despite its standard algorithm, while the spartan applies an advanced algorithm to get equal or better tail holding ability.

Posters on forums have talked about 3rd-axis info helping for piroing, but piros are less an information problem than a servo and linkage problem. Theoretically you could "spin the integrators" [hiller part] but half of that is relative wind trim and the other half relative-to-heli trim so I doubt the result would be useful. The bigger issue is that it takes super fast servos and stiff links to not have a lot of cyclic phase lag during a quick piro. (come to think of it I guess you could adjust the phase trim with yaw rate but it'd be pretty flaky, lots of iffy guesstimates involved)

[Skookum]

Hey All,

Just a note to say that if you bought your gyro on or before April 16th, and are still having any problems with random "kicks" or vibration sensitivity that fw1.02 didn't resolve, I am more than happy to replace your gyro with a newer one, just pm me or email. I'm worried some early-adopters are just accepting vib issues as normal.

After the first batch of gyros, an updated rev of the main sensor and a couple of other changes were made which seem to have eliminated the last of the vibration sensitivity, in concert with the updated fw. Sorting that out (and the cold flaw, now gone) was why the gyro was off the market for a few weeks back then. So far the new ones have had no reported vib-kick problems (but if you have, then I really want to hear about it).

[Sys-Ak]

Hy!

I am a new guy here, from Hungary, flying the T-Rex450 for 2 years and I bought an SK360 two weeks ago. I want to ask you about my setup, beacuse I have to swap the elevator and aileron hiller gain ratio compared with the default settings. Of course I tryed it out first, but the heli was thumbling around the elevator axis after I released the stick. (like the original v2 head with the loose dampers)

Current setup: T-Rex 450 SEv1.5, NEU1107H/1.5Y, 13 tooth pinion, CC Phoenix 45, Flight Power EVO25 2500mAh 3s1p, HS65HB ×3, GY611 light with S9257, R607FS and the SK360 of course :)
Total weight: 855g
Headspeed: 2800-3000 RPM
Note about the head: I am using 2 narrow spacers both side of the feathering shaft, so the dampening is quite stiff.

http://kepfeltoltes.hu/thumb/080616/Resize_of_DSCN7884_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080616/Resize_of_DSCN7884_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080616/Resize_of_DSCN7886_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080616/Resize_of_DSCN7886_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080616/Resize_of_DSCN7887_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080616/Resize_of_DSCN7887_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080616/Resize_of_DSCN7891_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080616/Resize_of_DSCN7891_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080616/Resize_of_DSCN7892_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080616/Resize_of_DSCN7892_www.kepfeltoltes.hu_.jpg)
http://kepfeltoltes.hu/thumb/080620/setup1_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080620/setup1_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080620/setup2_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080620/setup2_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080620/setup3_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080620/setup3_www.kepfeltoltes.hu_.jpg) http://kepfeltoltes.hu/thumb/080620/setup4_www.kepfeltoltes.hu_.jpg (http://kepfeltoltes.hu/view/080620/setup4_www.kepfeltoltes.hu_.jpg)

P.S.: I like the idea of using the spare output channel to switch between 2 advanced tabs, it would be very useful!
P.P.S.: Looking forward to your videos Bob! :)

[SpeedVision]

Hy!
I am a new guy here, from Hungary, flying the T-Rex450 for 2 years and I bought an SK360 two weeks ago. I want to ask you about my setup, beacuse I have to swap the elevator and aileron hiller gain ratio compared with the default settings. Of course I tryed it out first, but the heli was thumbling around the elevator axis after I released the stick. (like the original v2 head with the loose dampers)


So how does it fly now??? It wouldn't make sense to comment if you are happy with how it flys...

Have you used this http://www.helifreak.com/showthread.php?t=76895 tool to see how your SK sees your settings?

[Skookum]

Hi Sys-Ak,

I looked at your setup screen shots, and given how high you have the control rates set, the Bell gain is too low I think. Those two values need to be in balance for the heli.

"Control Rate" is how fast the gyro is being told it *should* roll or pitch in response to the controls. So at a 360 rate for aileron, full aileron deflection is asking for 360 deg/s. The gyro will try its best to achieve the rate you ask of it exactly and not let wind or quirks of the heli interfere.

But a gyro has to see error before it knows how to respond, so some direct control motion in response to the stick helps it perform better. That's the Bell Gain, and tuning it makes the heli do roughly what you ask of it directly, so there's less for the gyro to correct (the terms Bell and Hiller are from mechanical flybar mixing).

When you use the tuning dials (ie not disabled), it will use the % shown under Elevator and Aileron for that dial directly. The "base gains" then just set the ratio between them. So your gyro is using 22% for the bell gain and 360 deg/s, whereas normal for a Trex450 is about 40% bell and 210 deg/s. For 360 deg/s I'd expect around 70% bell to be right, with them not in balance you can get oscillation or sluggishness when you move the controls quickly.

Note the gyro will try to achieve the 360 deg/s even if it's impossible for the heli, like if the blades stall, which can cause some weird stuff at max control deflection if so, or oscillation at max collective during tick tocks. We've seen that start to happen at around 240 deg/s on the trex450.

[Sys-Ak]

Thank you for your answer Skookum!
I know that the bell gain is relatively low, I have allready tryed lower controll rates and higher bell gains, but find that stationary rolls and flips aren't smooth enough. They slowed down under load ( I mean when the collective pitch is bigger). Also tryed piroflips, but is was a mess.
With the current settings, loops and flips are totally smooth regardless the wind and the collective pitch. Real rates around the axes aren't reach 360°/sec even at a 100% cyclic command, but I can achieve faster movements by adding some bell gain.
The problem is that my experiences are hard to compare with your knowledge. If you can share some equations from the firmware, it would tell me more than a 100 pages of explanations. I also understands C, C++, C#, Python, Pascal and Delphi codes. ;)

Anyway, I'm going to make a video, it will explain things mutch better.

So how does it fly now??? It wouldn't make sense to comment if you are happy with how it flys...I am more than happy with the results. Never imagined that a flybarless machine can perform so well.
Have you used this http://www.helifreak.com/showthread.php?t=76895 tool to see how your SK sees your settings?Yes, but the manual is also easy to understand.

[SpeedVision]

"Control Rate" is how fast the gyro is being told it *should* roll or pitch in response to the controls. So at a 360 rate for aileron, full aileron deflection is asking for 360 deg/s. The gyro will try its best to achieve the rate you ask of it exactly and not let wind or quirks of the heli interfere.


Do control rates unilaterally affect the gyro responsiveness??

So, if we focus on hovering for simplicity, does the control rate have any impact on how the gyro will maintain the position of the hover assuming no stick inputs are given? In other words, could low control rates cause sluggish gyro response to external forces...?

I ask because I opt to use control rates to make the responsiveness the way I prefer as opposed to using expo on the TX. Since expo is taming the stick moves, maybe it's preferred over using control rates???

[Skookum]

>So, if we focus on hovering for simplicity, does the control rate have any impact on how the gyro will maintain the position of the hover assuming no stick inputs are given? In other words, could low control rates cause sluggish gyro response to external forces...?

Control rates and bell gain have nothing to do with hover stability, only pilot control. For example if you set control rates to zero and bell gain to zero, and spooled up on a level surface, you could lift the heli into a stable hover and it would fight wind gusts etc the same. There would just be no control.

>Since expo is taming the stick moves, maybe it's preferred over using control rates???

Expo has the same effect as it usually does, it moves sensitivity out to the edges of stick throw. Control rates is sort of like how much cyclic-swash action you have on a flybar'd heli. More = faster aileron and elevator.

>Also tryed piroflips, but is was a mess.

Part of the problem might be the bell gains not being in tune with the control rates :-) It might smooth things but will leave the gyro out of sync, always playing catch up. Also balance needs to be right under the mainshaft, and swash collective motion needs to be level.

[SpeedVision]

Skookum, thanks.

So, now if we assume that control rates and bell gain are at moderate settings and you want your heli to be more responsive, do you increase bell, control rates or both??? I'll leave expo out of the equasion to focus on SK functionality.

I know there is a correlation between them, but it's not sinking in...:thinking

[Skookum]

>So, now if we assume that control rates and bell gain are at moderate settings and you want your heli to be more responsive, do you increase bell, control rates or both???

In theory, both. The heli's rotor disk acts like a gyroscope, so the angular rate ought to be linearly proportional to torque applied, and torque ought to be (almost) linearly prop with cyclic pitch (aileron or elevator).

Long story short if you increase the rate by 25%, I'd expect the best bell setting to also be 25% higher. Because the bell part is accounting for gyroscopic stuff, heavier/longer blades should lead to higher bell gain, but higher rpm should mean lower bell gain or higher rates ([gyroscopic] effects go by rpm, but aerodynamic blade lift by rpm^2).

[caotri]

Hi,
Does any one try this on trex 600 eheli? And pleas epost pic of your head Modify for thius flybarless sk360. Thanks

[andersnorlin]

Anybody know the status for the

- LCD field terminal

- Switchable configurations from aux channel

[Skookum]

Hi Anders,

Both are in the working-prototype stage. The LCD screen has working hardware, but no software yet. For the switchable-configurations upgrade, there is a rough draft but it will be a few weeks yet before it would be ready for release. It's the testing that takes time.

A minor update has been posted on the website as well. The setup software now includes the "settings tool" table built-in, and a few other minor changes to make it easier to use. No need to update the firmware this time for 98% of users, the only change was to solve a compatibility issue that affected some futaba radios.

[mongo]

define "some futaba radios"

[puma1824]

define "some futaba radios"

from thier support page:

"Firmware changed to solve a compatibility issue with some Futaba radios (those with 70 Hz servo outputs)."

[andersnorlin]

What about these servos in a trex-450 flybarless with Skookum SK360 gyro, has anybody tested it? They seem lightning fast I have the JR DS285MG now and they run at 0.14 in speed, these would almost be three times faster.

Hyperion Atlas DS-11-GCB
Speed sec/60deg 6.0volt 0.05
torque kg/cm 6.0v 2.0

[Skookum]

"Firmware changed to solve a compatibility issue with some Futaba radios (those with 70 Hz servo outputs)."'

You'd have noticed the problem if you had it, the servos would twitch regularly. All new gyros will ship with the most up to date firmware.

[casey]

After adjusting the swash level at zero degree by using "Setup mode - Servo tab", I found that the swash are not levet at max + and - pitches, but there is no effect if I adjusted the transmitter's servo travel.


I have aready adjusted the value from the receiver closest to 0% and +- 100% by adjusting the end travel in the transmitter.

Pls help.

Casey

[t2o]

Hello casey,
If the sk is in flight mode, the swash tilt will be altered to compensate for "tail drag" and pitch up in FFF perhaps this is what you see? Check that it is level in setup mode and use your ATV's in the transmitter just like you normally would. I had the same question and that is what Skookum told me to do. Good luck

[casey]

Hello t02,
Thank you for your response.

I did check in setup mode, it is level in zero degree by using the servo tab - trims, but when the pitch is in max ( in my case is 12 degree), the swash plate is not level, I have used my ATV's in the transmitter but the servo travel did not move.

I use the travel adjustment in the servo tab, then the swash can be set to level in 12 degree.
However what about the negative pitch, I cannot adjust anymore as if I use the travel adjustment, it will affect the swash level in +12 degree.

Casey

[t2o]

casey,

Everything makes since, but the part about the ATV in transmitter not effecting the end point, without that working there is no provision for leveling the swash at the max/min. This one is over my head. I am sure Skookum will fix you up though.

[fireup]

ATV in the Tx does not adjust the swash to remove interaction, it controls the flip or roll rate (just like a HH tail gyro). To remove interaction on the swash,you need do it in the software, under the Servo Tab using "Servo Travel" values.

[t2o]

Here's what skookum sent me

>Also, to get a level swash plate at +/- collective extremes do I just
use my radio's +/- ATV's.

To level the swash through the SK360? That actually won't effect the
swash motion in flight mode properly. Adjust the servo travels in the
SK360's setup software should work. Yes I've considered having + and -
endpoints, vs one scale, but I worried that having a "kink" in the servo
motion curve could cause odd effects with the control system. I have a
test-version of the firmware that I'm trying it out on though, it may be
included in a future firmware update. Right now, if you set it to be
level with the trims at zero collective pitch, then use the travels to
get rid of unevenness at min and max, that should get it pretty close.
Note that in flight mode, the "tail drag compensation" feature will
cause deliberate uneven motion of the swash in elevator.


Regards


So it is clear that I mis-read what Art told me. Sorry about that casey!

I thought when he mentioned the servo limits that he was reffering to the atv limt in the radio. After reading it many times I am now seeing like Fireup say's that adjusting the radios atv is... "That actually won't effect the
swash motion in flight mode properly"... a bad thing.

I do understand your delima though, no + and - limit in the servo setup tab. I can either go + or - from the center to level the swash at the top or the bottom, but I can't do both. If its level at max + collective and the geometry is such, that it is not level at max negative collective, what do you do?