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HomeAircraftHelicopterMain Discussion › Cheap FBL setup.. do I need FBL blades?
10-13-2013 03:45 AM  4 years agoPost 1
Flyin for Jesus

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Troy, IL. 62294

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I have an Ace RC GT5 I put in my Blade 400. I removed the flybar and locked the flybar linkage piece so its flat and doesn't move.
Anyway, I was test flying it today and even with the swashplate gain maxed... it felt a bit drunk still ( much better than it did with a lower gain setting )
I'm thinking of getting the dampers that are for the 450X ( FBL so should be good ) but do I need FBL blades?
The movement wasn't too crisp as in expo or anything needed to keep it smooth. So I'm assuming ( from what I have read ) that I'm okay with the FB blades.

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10-13-2013 04:14 AM  4 years agoPost 2
AWittleWabbit

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Have you measured how much cyclic pitch you have?

Heli-itis sufferer.

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10-13-2013 06:40 AM  4 years agoPost 3
Flyin for Jesus

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Nope... The GT5 doesn't actually limit that. You can turn it down but it doesn't limit the cyclic pitch. I can adjust a number but it will only lower the roll rate. It will use as much cyclic as it needs to. ( If I understand it correctly )
This is all noticed in a hover. I can still mess with the PID loop some more. but I cannot get any oscillations with the gain maxed ( I'm assuming the soft dampers for this ) but I was wondering if I should get some FBL blades.
I assume flybared blades makes it twitchy... not sluggish.

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10-13-2013 07:57 AM  4 years agoPost 4
AWittleWabbit

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FB blades should give you somewhat more agility. I don't think FBL blades are going to help in that regard.

It wouldn't hurt to check total available cyclic travel though. I say this since you are doing a homebrew fbl head. If you are going from the swash-mixing levers-to grips, maybe the lever ratios are coming into play. Just a thought.

Maybe someone with gt5 experience can advise.

Heli-itis sufferer.

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10-13-2013 03:00 PM  4 years agoPost 5
icanfly

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ontario

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if you have a converted fb head you have the link balls on the grips in the lagging position. If it's possible to flip everything to put the grip balls leading the front of the blade this is the first step in eliminating the wobble. I have the following style on my Blade 300zyx-s and may change it to leading.

Leading grip balls command the swash to move up and down in unison rather than opposing. When the swash moves up the blade's leading edge moves up, and visa versa with down. This means the slop/flapping in the system is not fed back. Imagine f you will a ball tethered by a long stick, what end of the ball/stick is easier to maintain balance from? The leading control link fbl set up acts like that.

That's one, the other is that the fb set up has built in slop reduction in a mechanical sense because there's a lot of linkages. The old fb crew have studied this topic ad nauseam.

FB blades have more leading edge at the tip extending forward of the point of gyration, the centrifugal forces acting on the blade as a whole. FBL blades shift the point of gyration forward meaning the blade is hinged along the leading edge it's entire length more. There's less flap and slop absorption on the fbl set up because there's less linkages. The fluttering/flapping you hear is transmitted directly to the swash where the servos and gyro take over.
get some FBL blades.
I assume flybared blades makes it twitchy... not sluggish.

Get some high speed metal gear digital servos

have fun

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10-13-2013 03:25 PM  4 years agoPost 6
Ronald Thomas

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Gainesville, Fl, USA

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You can't just remove the flybar, slap on a FBL system and expect it to perform. There are many variable that affect how a FBL Heli flies like ball distances, swash to head ratios, blades, flexibility of the system, vibration, etc. you should really start from the beginning and do it right. Just putting FBL blades on it is not going to fix the problems created by the airframe. It may be better but not good.

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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10-13-2013 05:35 PM  4 years agoPost 7
Flyin for Jesus

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I just locked the flybar, all the balls and linkages are the same. Same leverage and movement. I've noticed the FBL heads have the blade grip linkage further from center... Meaning 1/2" of linkage travel = 10 degrees.
Since locking the flybar link piece... I retain the same leverages as stock and ( from appearance ) similar to a FBL head.
Also, I don't have any wobble... At maxed out gain. With the gain increase, I have a better feeling heli... But no more gain available. So, I'm assuming the soft dampers in the head are soaking up the FBL max gain quick reactions. ( the JR 3 blade head is solid with no dampening )
So, I'm assuming I need to tighten up the dampers. Just asking if the FBL blades will help it out or not.
I have both FB and FBL machines but none the same size so I can't swap blades to know what difference in the feel is.

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10-13-2013 05:59 PM  4 years agoPost 8
icanfly

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ontario

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take a look at this dudes version. I tried it and it's fine but has extra parts fbl doesn't need and is tall on the main shaft, but that's ok for stability. Also, some fbl head systems such as JR's utilize a crank system similar to the upper half of a fb setup.

Watch at YouTube

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10-14-2013 05:17 PM  4 years agoPost 9
Dee Flies 3D

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Farmington Hls, Mich - USA

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YES ~ you should be running the hardest dampers you can. I've done the locked flybar cage on heli's from 300size thru 50 nitro & if the dampers are too soft, you will get the mushy response you are describing.
In fact, on my 300 & 450 size, I even added shims to tighten it more..

Picts of some of the ones I did are in my gallery...

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10-15-2013 06:55 AM  4 years agoPost 10
Flyin for Jesus

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Well, the 450X dampers didn't fit... however, went to the hardware store and got the head finished up. Tomorrow will be test flying it again. I'll let you know how it goes.

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10-15-2013 02:11 PM  4 years agoPost 11
gwright

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Champaign Il

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work with the Derivative gain in the swash pid loop to get rid of the "drunk" feeling (wanders around never quite locked in). This is the "d-sense" setting. May actually need to go lower, not higher, try both directions, large adjustments,i.e... 15~20 points of change.
With that being said, yes you can adjust the cyclic throw, you do it with the servo travels (have to do all three equally for the swash). Do this while in programming mode, and the gyro's are not active. If in normal operating mode, they'll simply move to wherever the endpoints are set in the GT5, so you can't really tell how much cyclic movement you actually have in total. It needs 8 to 10 degrees cyclic (measured while in the programming mode) or it simply won't have enough to work properly. Under the tools menu you can adjust the inactivity timer from default to 25 seconds to something really high. I think 250 is the max, so it doesn't timeout and go out of programming mode while you're adjusting. Don't forget to go back out of programming mode before you fly though, the gyro's would be inactive <G>.

The biggest difference you'll see in fb versus fbl blades is in fast flight. With the fb blades it may tend to get pitchy and not "groove" in a line in high speed flight. You keep increasing I limit to the max and it keeps helping but never gets rid of the pitchiness totally till you put some good fbl blades on there with the forward CG. As for damping, you want it very stiff. If it's too soft, you slow down the control loop and the gyro can't do it's job appropriately. These are closed loop systems, so you speed one item up and you can speed everything up and things get better.

Gary Wright

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10-15-2013 03:26 PM  4 years agoPost 12
Flyin for Jesus

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Thanks Gary... The head is stiff enough to do some adjusting now. Didn't want to spend too much time the other day when I knew I needed to mechanically change it a bit.
I'm learning this FBL unit. I had tail wag again on this heli so I turned down the d sense like before but no help. I did a piro and noticed the tail made a huge jump then slowed and piroed smooth. Turned down the I setting and no huge jump and no more wag. ( I will dial this in more later ) I wanted to get the head to this over reaction point then back it down but it never got there so I saw the need for the damper tightening.
Last thing... The deadband... Is that like a backlash compensation or slop comp... I have a bit of slop like mentioned above with all the linkages. So, is this the adjustment to get the slop compensated for?

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10-15-2013 05:38 PM  4 years agoPost 13
Simmer

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no you don't need FBL blades

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10-15-2013 07:03 PM  4 years agoPost 14
gwright

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Deadband is the range where the gyro won't actually compensate for disturbances. It can help to tune a system to work with something that has some vibration, or as you mention, some slop. Full range on adjustment, however, is still a very tiny range. It's an extremely fine adjustment and may not have the breadth you need.

As another poster stated, no you don't necessarily need fbl blades. Your blades may be just fine, but if you do notice some pitchiness in fast flight and can't tune it out by raising I-limit or lowering I-gain, then a more forward-cg set of blades can help to cure it.

Gary Wright

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10-16-2013 04:05 AM  4 years agoPost 15
Flyin for Jesus

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With the head stiffened up... I was still able to run 125 gain on the swash. The d-sense didn't change a thing, so I started increasing the I for the swash. Still pushing it up and no funny acting yet. ( side note, I'm using the stock Blade 400 servos so I am not expecting perfection )
It just seems that when I let off the aileron or elevator... the heli takes just a bit to stop. I'm used to this FBL being on my 600 with servos adequate for a FBL head. Ran the D-sense to -50 and up to 75 with no seen affect. After hovering and adjusting for 2 batteries, I just took it out and flew it. It flew 10 fold better than it ever did with the flybar.
All in all, If this is as good as it gets, I'm more than happy. The way it used to fly, I didn't think I'd ever fly it again. Now, I might like slinging this thing around a bit. If I keep liking it... I'll just buy a FBL 450 when I put this into the ground next time.
Anyway, thanks for everyone's input.

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10-16-2013 02:27 PM  4 years agoPost 16
gwright

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Champaign Il

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Did you confirm that you have AT LEAST 8 degrees of cyclic pitch (measured while in programming mode so the gyro activity won't skew the results). If you don't have that as a minimum, and preferably 9~10, then it will be like the gyro doesn't have enough mechanical gain, and you'll end up with gains maxed out without enough effect. Kinda like moving the ball on the tailrotor servo in till it's only 4 or 5 mm from center. You'll end up with a poor feel in the tail and maxed out gains. It's entirely possible to end up the other way too, but I doubt that since you're gains end up at maximum.

Gary Wright

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10-16-2013 04:57 PM  4 years agoPost 17
Dee Flies 3D

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Farmington Hls, Mich - USA

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I can tell you - from converting a Blade CP Pro & a TT Mini Titan to FBL [similar to what you are doing] that ditching those cheapo servos will be the BEST investment for flight control. Even the Hitek 5055MGs will give the machine the finer control input I think your lookin for.
You would have to re-do the setup in the GT5, but it'll be worth it...

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10-17-2013 04:04 AM  4 years agoPost 18
Flyin for Jesus

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I have +/- 10 degrees of pitch.
This is far from an ideal setup... If I see some better servos for cheap, I might go for it. If all I lack is a bit of precision, I can live with it. It's a high improvement over its previous flying abilities.

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10-17-2013 03:21 PM  4 years agoPost 19
gwright

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Is that +/-10 collective or cyclic?

Gary Wright

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10-18-2013 03:32 PM  4 years agoPost 20
Flyin for Jesus

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Collective.

Oops... Just re-read your post. I'll check the cyclic when I have a chance. I actually don't know what I have there.

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HomeAircraftHelicopterMain Discussion › Cheap FBL setup.. do I need FBL blades?
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