Why is the swash all over the place?

[rhysduk]

Have been trying to get my head around this all night...
Im getting the point of giving up

My swash is level mid stick, but off at high and low stick. What gives?

All servos are at 90 degrees.
Anyone in south wales want to spend some time helping me get this setup properly?
It flew great first time out but noticed the swash wasnt level, it took a bit of a bump and im waiting for some bits to arrive. Thoguht Id take a look at the swash... BIG mistake

[Eckchaz]

Not all servos travel the same distance of centre the same... using your swash leveller tool.. check it at mid stick.. then at both full neg/Pos to see if its still level... if its not.. use your end point in your tx to adjust it, until its level throughout the whole travel.

[cjcj1949]

The end point adjustments is one way to do it. Your problem maybe that the gains in the swashplate screen are different. Which model and tx is it? Some models need different gains.

Chris

[rhysduk]

Thanks eckchaz, ill have a look tomorrow.

Chris, tx is a futaba 8fg. Subtrims are all 0. Dnt talk about gains lol I dnt have a bloody clue about that, esp gyro stuff. Everything I read on the net is different!! Thanks

[Mslater]

Thanks eckchaz, ill have a look tomorrow.

Chris, tx is a futaba 8fg. Subtrims are all 0. Dnt talk about gains lol I dnt have a bloody clue about that, esp gyro stuff. Everything I read on the net is different!! Thanks

You've got the best TX to get it done quickly. In the linkage menu you will find the end point menu with travel adjust setting. USE TRAVEL ADJUST - NOT THE END POINT





The 8fg is not easy to program - I take that back it is easy to program but you have to program each flight mode. EG gyro gain is set for each flight mode - if you forget to set it you can get a nasty surprise when you go to that mode. I forgot to program throttle cut, my first auto was quite interesting !!!

futaba.jpg

[rhysduk]

Thank you. I knew it was something relatively straight forward!
Ill have a ganders tonight as long as I can find my swash leveller! Not seen it since I bought it!
If I dont, what ball link should I be using for reference? Elevator? (rear link) ...

Re: Gain.. Ill start a new thread about that when I hit it, its a completely foreign language to me especially with these idle up modes and so forth... sigh. I have to lower my gain for my gyro as its a little twitchy and when i punch the Collective the tail goes to hell! I can fly it, but I don't understand it

[waveydavey]

Re: Gain.. Ill start a new thread about that when I hit it, its a completely foreign language to me especially with these idle up modes and so forth... sigh. I have to lower my gain for my gyro as its a little twitchy and when i punch the Collective the tail goes to hell! I can fly it, but I don't understand it

If you punch the collective and the tail doesn't hold then the gain needs to go up I'm afraid not down, look at the gain as being the speed or rate of change that the servo reacts with. A low gain will give a slow reaction and vice versa. You need to understand in order to fly otherwise you'll just chase your tail, so to speak. Read some of the excellent posts on here and other relative material elsewhere on the net, here you go 1 search and all you need to know about tails and gyros. Gyros and tail gain

I think Steve posted a really good article on gyros on here, I'll see if I can find it.

Your tail not holding could be down to other things such as tail authority, distance of the control ball on the servo horn, slop in the tail linkage causing a wag.

[rhysduk]

Mslater;
Ok so I'd had a go and got the swash as level as I can, I think.
I altered the endpoints as you suggested above to the following:

High Stick: 6: Pitch 135 92 100 135
Low Stick: 1: Ail 135 100 129 135
All others are at 135 100 100 135 (PS: Whats NDL stand for? Cant find it in the manual)
I now have a near enough level swash at low, mid and high stick (mid is a tiny bit off). Is that OK ???

Thanks for the link waveydavey... I've had a read and its quite good. i need to get to understand headspeeds, idle up modes and then I'll have a crack at that. Do I even need 3 idle-up modes? This is what the tx is set to at the moment, with 80% gyro gain in normal, and 50% in idleup1,2 and 3.

[cjcj1949]

Thanks eckchaz, ill have a look tomorrow.

Chris, tx is a futaba 8fg. Subtrims are all 0. Dnt talk about gains lol I dnt have a bloody clue about that, esp gyro stuff. Everything I read on the net is different!! Thanks

I'm not talking about Gyro gain, but swashplate gain. There's a screen that shows all the cyclic servos at the same time and a % next to them. Its that % that you need to check.

Chris

[rhysduk]

Would that be AFR?
AIL, ELE & PIT are all at 50%.
Neutral is POS: 49%

Sub-Trim in the SWASH menu for AIL, ELE & PIT are all 0

[waveydavey]

I'm not talking about Gyro gain, but swashplate gain. There's a screen that shows all the cyclic servos at the same time and a % next to them. Its that % that you need to check.

Chris

I think you mean swash limit or mix amount. Theres no gain for cyclic on a flybarred heli. The swash mix/limit is the controlling amount of each control on all 3 servos that mix the cyclic and collective.

[cjcj1949]

Yes. Its called swashplate mix on my DX7. I don't know why as its a gain figure really. It's a % multiplier. Sorry if I used the wrong term.

Chris

[waveydavey]

Yes. Its called swashplate mix on my DX7. I don't know why as its a gain figure really. It's a % multiplier. Sorry if I used the wrong term.

Chris

I could be wrong Chris but the accepted meaning/use of gain is rate of change in a control loop circuit such as gyro gain. The swash mix is a rate figure given in %age. No matter what you do with the value it only limits the movement of the cyclic/collective mix. It doesn't change the speed or rate of change of a reaction.

[cjcj1949]

Gain is defined as Vout/Vin in electronics.
or Output = Input X Gain for an amplifier

In a control loop an increase in gain of the amplifier will result in a faster response. Too much gain results in an overshoot. Even more gain results in an oscillator which is what drives our transmitters. (Without getting into phase shift and stability criterea)

Heli flyers have a different definition as you say.

Chris

http://en.wikipedia.org/wiki/Gain

[waveydavey]

I don't think it is different for the definition of gain when applicable to the rudder or the gain used for the cyclic on flybarless models. The swash limit is not a gain function it's a limit. The gain function is exactly as Wikipedia so eloquently explains it a speed of reaction of the tail to a given input