clovus

Howdy,

The more threads I read the more I hear - LITTLE control stick movements to help smooth out your hovering. With this in mind I have noticed that I still tend to overcorrect ...ending in some interesting moments. Will dailing in some exponential help reduce this? Any ideas on how much exponential and on what channels? I had a look on my controller and it has the option but I am unsure if it should be - or +ve.

thanx.

Sao

YEs a little Expo can help here

You should set it on Aileron and Elevator

Start off with 10% and make 5% adjustments if its too much or not enough that will get you started.

As to wether to use +ve or -ve depends on your Tx JR and Futaba Differ here, on Futaba you use a -ve figure add expo and the opposite on JR (from memory)

Just take one channel, add some expo to it and observe how this effects the servo movement when you operate the corresponding Tx stick.

-pkh-

My Feedback: (2)

This is where having a graphical display on your TX comes in handy... you can visually see how much exponential your dialling in, and which way +/- goes...

tanasit

Exponential will either make the sensitivity around the mid stick more or less sensitive. In your case of overcorrection, you will need to lessen the sensitivity and Futaba will assigh the minus sign for this. The easiest way is to set it while holding the AIL or ELE stick off center, enter the number and make sure that the movement of the swash plate become "less" and not MORE, so you will get what you want.

_Buzz_

I've been teaching my boss to fly my micro recently and I've proved beyond doubt that making the sticks less sensitive doesn't stop over controlling by a newbie pilot. The reason is simple.....they don't wait that fraction of a second to see what's happening....if it doesn't happen RIGHT NOW, they give it some more. I found that it was actually counterproductive, because now that the sticks are less sensitive, they need MORE movement to counter the over control and it can't be done quick enough.

When we had the fly in in Gallatin TN last year, I had my first chance to talk to quite a few micro flyers at once and to swap set-up data etc.The one thing that came across was that almost all of them prefered my "Very Sensitive" set-up once they'd flown it and managed to hover steadier and for longer than with the less sensitive set-ups they were recommended to learn with.

I would say "Keep it as sensitive as you can and learn to move it less."

clovus

If more sensitivity was better then I would be going +ve?. I suppose the best thing I can do is to try dialing some in and seeing if my hovering gets better or worse. I can control the heli in a hover reasonably for the first 15-20 seconds then maybe I lose concentration and things start to go a bit loose. Tonight is my first chance to fly so will be very interesting to see.

_Buzz_

I don't like expo...my brain knows that if I move the stick X amount I get a response...if I want twice the response I move the stick 2X....with expo that doesn't happen....I prefer LINEAR !!!

If you have the normal "soft in the middle" expo, you move the stick a bit to control a movement the heli has made and it's not enough, you automatically move it more. But now the bit more gives more reaction than the first bit did, so you over control even more.

Once you can fly, then use expo to polish your flying, but it's absolutely no good for learning.

Flyfalcons

With today's non-linear movement servos, it takes about 30% expo to make the conrol movement linear. I have 30% Expo in my Raptor 60 (the manual recommends this) and it flies great.

BarracudaHockey

My Feedback: (11)

You beat me to it Falcon, you can't get true linear response with round servo wheels.

_Buzz_

Isn't it amazing how many people will jump in and argue with a reply without even bothering to read the original question.

1. I was answering to a guy learning to fly a micro heli.
2. 99.9% of micro heli servos ARE linear.
3. I did say use it to smooth your flying WHEN YOU CAN FLY.

You're forgetting one very important thing my friend. It is true that the link fastened to the servo arm moves less per degree of servo movement the further the arm gets from the 90 degree point (in both directions) BUT the item that the rod is connected to at the other end works in exactly the opposite way and so the rotation output more or less equates to the rotation input.

It doesn't matter what shape the servo wheel is either.....round, square or just a lever, the geometry is the same.

BarracudaHockey

My Feedback: (11)

True only if the distance between the spline and the ball link is the same between the other ends ball link and its pivot point. Otherwise you still introduce expotential movement.

_Buzz_

But do you agree that if the geometry is right, you can get perfectly linear response from a round servo disc ????

Your answer HAS to be YES and you know it. So why did you post as you did saying it can't be done. Are you not used to coming up against people that DO know a thing or two......newbies are easy to fool aren't they ????

I'm 58 and been in aeromodelling for 50 years and a precision engineer for 40 !!!

BarracudaHockey

My Feedback: (11)

I love a cereberal discussion. Most information aimed at newbee's is to educate them and make them think, detailed engineering discussions are over kill. I'm an expert by no means and my posting intent is to help.

To respond, yes perfect geometry you can get linear response. However a quick look at most model helicopters should tell you that perfect control geometry is rare. Most are a comprimise of some sort between form and function, manufacturing process and asthetics therefore you rarely get that perfect linear set up and you stand to introduce expotential and differential throw. Will any of this affect the average model helicopter or flyer? Probably not.

As far as "coming up against" I don't consider this pugilistic at all, I'm always up for learning something and you clearly have a back ground in the field.

Cheers mate!
Andy

-pkh-

My Feedback: (2)

So... what kind of engineering degrees do they give out to 18 year-olds over there???

_Buzz_

I don't remember stating I had a degree in anything...as it happens I do, but I stated "Precision Engineer". I started making Steam Loco's with my father at the age of 10 and have been fulltime in Mechanical Engineering ever since and for the last 33 years had a Mechanical Engineering degree and am a Mmeber of the Institute for Mechanical Engineers.

I only made refence to my age and qualifications just to show that the B/S that would frighten a newbie into submission has little effect on me other than to raise a laugh.

-pkh-

My Feedback: (2)

Ahhh... you meant that kind of engineer... if that's the definition, then I was an electrical engineer at the age of 8, but didn't get my electrical engineering degree 'til much later!

BarracudaHockey

My Feedback: (11)

I wasn't trying to frighten anyone into anything. Just pointing out that you dont get linear response from round servo wheels. I should have probably stated.........In most cases.

rusirius

Clovus,
I had the exact same problem with my micro at first... It was all over the place... Then I kinda figured it out... It wasn't me, and it wasn't my expo settings... True I was so used to the nitro which had much quicker cyclic response, but I played around with the expo and it really didn't help much.. POSITIVE expo actually seem to help a little (making it MORE sensitive around neutral) But too much and I lost it...

THEN! It hit me.. I was only attacking half the problem... What I was experiencing was my stick movements being too "slow"... Because it took so much stick movement to put in a correction, but the time I GOT the stick where it needed to be, the heli had already shifted and needed something different... Positive expo helped, cause it made it require less stick movement, but then it got VERY sensitive around mid-stick... So too much blew it.... What I did afterwards made a TREMENDOUS difference... Give it a try.... Go into the Swash AFR menu (assuming futaba.. not sure what JR calls it) and crank the elevator and aileron mixes up a bit more (to give more movement)... THEN go into your dual rates menu and set the rate to 140 - 150%.... Then set a bit of NEGATIVE expo.... Maybe around 5 or 10%... Give that a try... what you'll find is that your neutral is still "easy", but when you have to enter corrections it can be done quickly and with little stick movement... It made a WORLD of difference for me.. Things almost as stable as my nitro now...

rusirius

Ohhh, that was assuming you have CP and a 120 degree swash... If you have FP, then you won't have the swash AFR stuff... Just crank the rates up and add some expo....

_Buzz_

Thank you Rusirius...at least a meaningful comment from somebody who DOES know something about flying Micros.

BarracudaHockey

My Feedback: (11)

Wow, didn't mean for you to get your kilt all up in a wad. I'll now bow down to your obviously superior intelect.

_Buzz_

The thing that gets my "kilt in a wad" as you put it, is people handing out WRONG advice. Especially to the vulnerable newbies. Micros are a totally different kettle of fish to nitros and even larger elecric helis and therefore need proper knowledgable advice handing down.

I've got no doubts that the advice you gave would suit certain situations, but NOT micros and it WAS a micro oriented question.

BarracudaHockey

My Feedback: (11)

Bowing again. Thanks for the correction.

Do us a favor, take it easy on the coffee.

clovus

chill out guys!

Any help is appreciated but my poor cerebral cortex can't cope with too much info -hey it's hard enough trying to move two little sticks all directions whilst looking at a mechanical bird of doom trying to attack every fragile thing in the house -including me/wife...

That you rusirius (classic name, the irony is not lost on me esp. given the previous posts - very entertaining but a bit over my head) I didn't have much luck with the expo as I changed to a lipo battery and now have a host of all sorts of other problems eg. weight balance, shaking..not me the heli... well I'm shaking too.

I have figured out where the dual rates are so will bump them up and try some -ve expo once I rebalance the heli and check over everything..

Somebody on these forums tags their name with "you should've told me it was going to be this expensive" -or similar, maybe I should add you should've told me it was going to be this frustrating, but once you've had that first controlled hover... can't stop now.

I guess it's like anything - took the wife fishing for her first time- Cast teh rod out for her, she waited for maybe 10 seconds after giving her the rod and she pulls in a whopper whilst I got nada all day - ha ha.

Flyfalcons

Hey Buzz you need to settle down a little. The original question did not mention micro helis and in the case of the nitros that I have, they do take some expo for a linear response. I do have a micro and though the servos are not linear, it doesn't need expo because of the low headspeed and generally slow response.