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HomeAircraftHelicopterFlybarless Rotor Head SystemsSkookum › Help with FBL swash mixing.
10-08-2012 12:06 PM  5 years agoPost 1
Rotormaster

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Australia

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Last night I was setting up the SK540 and could not seem to figure out how to get the swash mixing correct. There are two panels to mess around with; one is the 'swash mixing' panel and the other is the 'swash servo' panel. What I don't understand is that these two don't seem to fulfill the purpose they should. For example, the setup wizard says that if the swash mixing is not correct, simply reverse the swash servos until they all move in unison. However, when you go to the swash servo panel and reverse either the left, right or centre servo, it doesn't just reverse that servo but instead changes the way they all behave. Why does it do this?

It seems that I have tried almost every possible combination between all 3 swash mixing menus (including the one on the radio), but apparently not all. Can someone just tell me which boxes to check and un-check so I may stop banging my head already?

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10-08-2012 01:21 PM  5 years agoPost 2
jcflyer

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Terrytown, La.

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Only check the boxes to the servos you want to reverse.

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10-08-2012 03:06 PM  5 years agoPost 3
pH7

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Sterling Heights, MI - USA

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I don't have a Skookum, so I am just taking a shot in the dark here. It sounds like you have CCPM mixing in your radio. I assume that you need to set 1 servo - normal swashplate mixing in the radio.

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10-09-2012 06:13 AM  5 years agoPost 4
Rotormaster

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Only check the boxes to the servos you want to reverse.
Like I said, it doesn't work that way. I go to the swash servo menu to reverse an individual servo, check the box, and it changes all the rest of them out of generosity.

So that menu doesn't seem to function properly (or as described). And then when you want to reverse some of the servos collectively, you go to the swash mixing menu and check or uncheck one of the boxes, and it does absolutely nothing. So that menu doesn't even work at all!
I don't have a Skookum, so I am just taking a shot in the dark here. It sounds like you have CCPM mixing in your radio. I assume that you need to set 1 servo - normal swashplate mixing in the radio.
My radio swash setup is set to a 120º, 3 servo configuration... and the SK540 swash configuration has been setup thus.

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10-09-2012 10:32 AM  5 years agoPost 5
Rotormaster

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Seriously? Nobody is willing to help me out?

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10-09-2012 01:23 PM  5 years agoPost 6
georgi UK

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=] Rotor, your Tx is setup incorrectly, it should be set to "one servo" swash type, all mixing is done in the SK, not in the handset!

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10-09-2012 02:40 PM  5 years agoPost 7
Ravenhyper50

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Canada's Capital

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+1

Raven

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10-09-2012 03:31 PM  5 years agoPost 8
Rotormaster

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=] Rotor, your Tx is setup incorrectly, it should be set to "one servo" swash type, all mixing is done in the SK, not in the handset!
Yeah, I figured it out already. I tried what pH7 said when I got home tonight just because I couldn't think of anything else... to my delight it actually worked.

I proceeded to finish the setup... at least until the end when I realized the swash still moved like my flybar when given cyclic input, which obviously doesn't work with the geometry of the swash to main blade linkage of the DFC head. At least it wasn't too long until I found the 'phase trim' tag to adjust for the phase lag. Just don't understand why this isn't mentioned anywhere in the instructions.

Anyway I should be good to test fly soon. This will be my first FBL heli, so depending on how it goes it will help me decide on my next bird.

Thanks guys.

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10-09-2012 05:54 PM  5 years agoPost 9
HeliKopter Ken

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Gray, LA

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Use all the set up wizards in proogram. The Sk540 is my first FBL unit and it flys perfect. No complaints at all with it.

Aurora, Raptor 90 FBL, Logo 600SX

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10-10-2012 06:55 AM  5 years agoPost 10
Rotormaster

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I put training gear on the heli and did some test hops in the driveway early this morning. I cannot for the life of me get the phase lag timing correct. I tried playing with the swash phase tab and even tested every 10° but it was always off. The closest I got was at 75° positive, where I could hover the heli above the ground, but would have random and violent pitching.

The cyclic gain is set to 50, but I got better results with the gyro inhibited all together (cyclic gain at 0).

Any ideas?

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10-10-2012 08:01 AM  5 years agoPost 11
KevinR

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Vancouver, BC Canada

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Which helicopter are you trying to set this up on? Also, which radio are you using.

Did you go through the setup wizards? After going through the wizards, while sitting on the bench everything should be moving in the proper directions like a normal flybar heli. If not, something obviously isn't set right either on the radio or in the software. It's easy to forget that you shouldn't be changing settings on your radio, other than expo I think any changes should be made in the software (someone correct me if I'm wrong).

When you say random and violent pitching, do you mean fore/aft pitching or positive/negative blade pitch changes?

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10-10-2012 08:31 AM  5 years agoPost 12
Rotormaster

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The heli is a 450 pro v2 controlled by a dx8.
After going through the wizards, while sitting on the bench everything should be moving in the proper directions like a normal flybar heli.
But if everything is moving like my flybar, what is going to correct the phase lag? Am I missing something?

Oh, and by pitching I meant that the cyclic would do things not commanded by me.

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10-10-2012 04:34 PM  5 years agoPost 13
Keygrigger

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Mississauga, Ont. Canada

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You have a 450 Pro V2 but you have not said what flybarless head you have. At this point, it sounds like you have the stock flybar head, or is that wrong?

Don

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10-10-2012 04:35 PM  5 years agoPost 14
KevinR

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Sorry, what I meant to say is with the 540 plugged into your computer and your radio turned on everything should move as normal (unless my memory is failing). Actually, with my heli sitting on the ground ready for flight everything moves in the proper direction when I input commands. The only difference is the delay in returning to neutral.

What do you mean by phase lag? Are you referring to the phase trim setting? I didn't need to touch that with my Logo.

From the Skookum Wiki:
Phase Trim
Rotates the plane of cyclic action about the main shaft, to allow correction for gyroscopic and aerodynamic effects. It also allows the use of 3 or 4 blade rotor heads. For example, setting phase trim to 90 degrees would make full left aileron stick deflection tilt the swashplate fully forward. Note that the phase angle will vary with rotor rpm and load so a “happy medium” value must be sought when setting this value. See Section 12 of this user’s manual for a step-by-step description of how to check the cyclic phasing.
Which can be found here:

http://www.skookumrobotics.com/wiki...#Swashplate_Tab

Did you go through all the setup wizards? Was everything moving as it was supposed to be on the bench? This was my first FBL heli, the wizards walked me through everything step by step. The only thing that had to be done at the field was fine tuning the 'feel' and gains.

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10-10-2012 06:47 PM  5 years agoPost 15
georgi UK

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UK

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=] you may have a double servo reverse, all Tx servo channels need to be set to normal, all reversing is done in the SK software, not in the handset.

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10-11-2012 01:19 AM  5 years agoPost 16
Rotormaster

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Australia

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You have a 450 Pro V2 but you have not said what flybarless head you have. At this point, it sounds like you have the stock flybar head, or is that wrong?
Post #8 I said that it is the dfc head.

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10-11-2012 01:41 AM  5 years agoPost 17
pH7

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Sterling Heights, MI - USA

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I proceeded to finish the setup... at least until the end when I realized the swash still moved like my flybar when given cyclic input, which obviously doesn't work with the geometry of the swash to main blade linkage of the DFC head.
Yes, it does. Try not to over think it all. You absolutely do want the swashplate moving just like it does with a flybar.

The short reason this is true is: "that is just the way it is".

The slightly longer version is to look up gyroscopic precession. Any input to the spinning object will actually take effect 90 degrees later. You can spend a lot of time trying to understand it or just accept that it does work correctly as designed.

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10-11-2012 01:54 AM  5 years agoPost 18
Keygrigger

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Mississauga, Ont. Canada

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Ok, now that I see that I passed by that, the DFC head cannot be changed at all. It is mechanically set to 90 degree phasing so no mechanical mis-alignment can occur. It is possible in the Skookum software to adjust for some strange motion to the left or right when forward collective is applied but I really can't see that ever being used. When Align changed a number of their heads to have the swash driver base as part of the actual head, that meant no more worrying about not being 90 degrees with the swash driver and blades. You should fly the heli as it sits and it should fly like a champ. Take care.

Don

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10-15-2012 12:08 PM  5 years agoPost 19
Rotormaster

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Australia

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PH7, I know exactly what torque-induced precession is, but I think what you are talking about is phase lag.

You were right though... I was indeed 'over-thinking' the issue (I was thinking myself in circles, in fact!). I got myself all mixed up when looking at the phase angle and the torque-input angle, but never mind.

I got it all working, and I took it out for a flight on Sunday. It flew Ok, but I wasn't overly impressed with it... I almost couldn't tell the difference to my flybar, so I was sort of scratching my head thinking "where is this fancy gizmo I waisted $230 on?" I'll have to play around with the setting I guess before making further judgements.

Anyway, thanks for all the help guys.

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