RunRyder RC
WATCH
 1 page 776 views POST REPLY
HomeRC & PowerAircraftHelicopterFlybarless Rotor Head SystemsFutaba CGY › Is it unusual to have 100% gain?
09-08-2013 08:44 AM  5 years agoPost 1
wbplomp

rrApprentice

Den Haag, The Netherlands

My Posts: All  Forum  Topic

Hi,

I have a T-Rex 700E DFC with a CGY750. It flies fine, except for the tail performance.

But my cyclic gain is 100% without any issue. I don't notice any difference between lets say 90% or 100%. Is it unusual to have 100% cyclic gain?

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
09-08-2013 01:39 PM  5 years agoPost 2
unclejane

rrElite Veteran

santa fe, NM, USA

My Posts: All  Forum  Topic

You know... I've noticed this also with the CGY, it tolerates maxed out gains pretty well over other FBL units I've used. However, you will start to see problems like bounces and shimmies at certain headspeeds, I have found.

I run pretty stately, low headspeeds and that tends to make the gains do even less with my 750's. But that's probably more a function of the helis than the unit. Its control loop is probably more optimized for more responsive situations like higher headspeeds and lightweight blades.

But especially with the 1.31 firmware, my trex 700E running 1500rpm or somewhere in there with heavy Curtis 710 V2 FAI blades, still seems to work fine with the 750. But true gains from 70% all the way to the max are barely detectable in flight.

So to me, I don't consider that a problem with the unit, it's probably working normally but just with a stately performing heli in my case....

LS

PM  EMAIL  Attn:RR  Quote
09-08-2013 03:15 PM  5 years agoPost 3
wbplomp

rrApprentice

Den Haag, The Netherlands

My Posts: All  Forum  Topic

Thanks for the info. Have you seen Nick Maxwell his setup videos? He tells you about the bounces after setting maximum gains. You should increase your I.Gain. That is exactly what I did after a few flights. The model now feels a little bit more crisp.

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
09-08-2013 03:30 PM  5 years agoPost 4
unclejane

rrElite Veteran

santa fe, NM, USA

My Posts: All  Forum  Topic

Yep, those are great vids. He covers basically the entire setup.

I have actually not messed with the gains any on mine yet. The two machines I have my 750s on fly pretty much the way I like with the defaults. I just use flight mode 3 and that's pretty much it.

I do turn off the expo in normal mode, tho, since I fly that mode with the gyros fully off (0% gain) and prefer more control authority around center stick. But that's the only change I've really made.

I don't remember where I have my cyclic gains in AVCS mode tho. I think it's around 65% or somewhere in there...

LS

PM  EMAIL  Attn:RR  Quote
09-09-2013 05:01 AM  5 years agoPost 5
Dr.Ben

rrMaster

Richmond, VA, USA

My Posts: All  Forum  Topic

Except for competition hovering, the use of gain at or beyond 70% is largely ill advised because it will lead to a sticky feel in the controls, especially with more aggressive and complex 3D. The fact that you CAN run a lot of gain does not mean that you SHOULD run a lot of gain. The DFC models have a comparatively lower amount of cyclic change in the blades per unit of swash tilt, so effectively you are running more control resolution which will thus tolerate higher electronic gain. Increasing I gain is never used to tune out any bounce behavior. You use more I gain when the model's nose deviates with collective input during maneuvers such as rolls or when the model, especially on the pitch axis, feels loose or fails to maintain heading. Excessive I gain will induce bounce behavior and also lead to a sticky feel to the model in flight. Small adjustments in D gain CAN be used, along with incremental decreases in total gyro gain, if a particular model exhibits a bit of bounce on the ele axis. For the most part, the default parameters are quite good as far as bounce is concerned.
In development of the current firmware, there was never any effort to optimize the system for lighter blades or higher headspeeds. It works quite well across a relatively immense rpm range of from down in the 1100 rpm range up to well over 2000. No FBL controller does sport/3D well with particularly heavy blades because the spinning mass of the blades kills too much cyclic response.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

PM  EMAIL  GALLERY  Attn:RR  Quote
09-09-2013 04:03 PM  5 years agoPost 6
wbplomp

rrApprentice

Den Haag, The Netherlands

My Posts: All  Forum  Topic

Thanks your input Ben. I must honestly say I am a bit confused now. Probably because English is not my primary language I try to avoid tweaking as much as possible.

Currently my cyclic gains are both at 100%. And I have increased my I.Gain to 120%. I think it feels better, but I am not totally sure it introduces another issue. There is only one thing that I think is happening.

When I do forward or backwards stationairy flips it feels as if there is collective input. The model gets a bit jumpy. I have checked a SpeedCmp settings for elevator or something like that on the bech. But I can't see any difference changing the value. I know it is off-topic, but you know what I mean?

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
WATCH
 1 page 776 views POST REPLY
HomeRC & PowerAircraftHelicopterFlybarless Rotor Head SystemsFutaba CGY › Is it unusual to have 100% gain?
 Print TOPIC  Make Suggestion 

 2  Topic Subscribe

Sunday, October 21 - 5:53 am - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

The RC discussion world needs to consolidate. RR is now one choice for that. Its software is cutting edge. It hosts on-topic advertising. Help RR increase traffic buy making suggestions, posting in RR's new areas (sites) and by spreading the word.

The RunRyder Difference

• Category system to allow Rep/Vendor postings.
• Classifieds with sold (hidden) category.
• Classifieds with separate view new.
• Answer PMs offsite via email reply.
• Member gallery photos with advanced scripting.
• Gallery photo viewer integrated into postings.
• Highly refined search with advanced back end.
• Hosts its own high end fast response servers.
• Hosts thousands of HD event coverage videos.
• Rewrote entire code base with latest technology.
• No off-topic (annoying) click bait advertising.
Login Here
 New Subscriptions 
 Buddies Online