Expo/DR question for Quad

[blkspade]

Hey all,

So i've been fpving my quad for a while now and set it up to be really stable in flight. I have set it up with two diff. settings. Since I'm flying with futaba, the expo settings are backwards.

It's flying perfect right now but i really want to understand this. For planes, i totally get it but with the quad, the more i think about it the more lost i get.

Setting 1

Ail,El - Dr at 35% with +40 expo

Setting 2
Ail,El - Dr 45% with +25 expo.

Alright, i might be overthinking this here..
If you set the D/r low enough, and the Expo high enough / and the Expo low - D/r high will they meet in the middle?

With a quad you really don't have servos so i think that's whats throwing me off

Basically i have it set up to be able to fly around really stable ( setting 2 ) then when i want to really just hover and video something flip it down for a even more stable flight ( setting 1 )


So far how i have it set up has been working fine, but now i'm wondering if it really is or so close to being the same thing that it's not really doing anything.


I guess i can just do
Ail,El - Dr 45% with +25 expo.
Ail,El - Dr 45% with +10 expo.

I know its just personal preference but just trying to grasp how it works with a multi roter

Sorry if this doesn't make sense.

[Mongrel Gear]

Hi mate,

Wow... you have confused yourself LOL!!

OK... Expo basically changes the way the control surface responds to your sticks. It doesn't matter if you have servos or not. In fact, copter pilots use a similar system but they call it throttle curve - but I digress.

Let's break it down into 2 areas...

Expo and End Point (often referred to as Dual Rates)

Let's look at the End Point first. If you bring your end point down to say 45% it means the control surface will only travel 45% of the way at full stick. Very useful if you don't want your copter doing barrel rolls.

So... EXP changes the curve on the control surface - in your case, making the control surface less sensitive around mid stick. This helps to reduce sudden changes in control as you have to move the stick further to get large throws.

In some cases 3D for example, some guys like to use reverse EXP and make the controls act really quickly at mid stick. But again I digress.

What you need to make sure you do is get a good balance between EXP and End Point. In your Futaba you will see you graph that shows you exactly what the control surface will do with the setting you have.

The two are very different settings and will not really "meet in the middle" That said, if you have say 100% EXP and drop the DR low enough, you will get ugly results.

I hope that helps.

Cheers
MG

[blkspade]

Thanks.
That actually makes sense. I guess i was just making it more complex then it needed to be lol. I guess since I've been using a little less dual/rates and a little neg. expo i was getting confused of how it worked.
I understand it now.

[Pen]

Just making sure you know that for Futaba, positive expo makes controls more sensitive around mid stick.

Most people use expo to make controls less sensitve around mid stick which would be positive expo for Spektrum and negative expo for Futaba.

I know you said you knew Futaba was backwards but you posted that you used +expo???

[blkspade]

Yeah i know its backwards..

But yes i have had it set up with + expo and dropping the D/r with +expo i was able to fly it more stable. That was why i was confused. lol

[Mongrel Gear]

Hmm... I think you might be more confused than you think. A Pos Expo will make it very quick to react. Try changing it to Neg Expo and you will how much more "docile" the craft will be.

[blkspade]

Hmm... I think you might be more confused than you think. A Pos Expo will make it very quick to react. Try changing it to Neg Expo and you will how much more "docile" the craft will be.

Oh, no i totally understand that. It seems pretty good with the settings i have, but will play with it.

[Mongrel Gear]

I guess - whatever works for you. But swap them around and see what you think. It's always good to see how things work.

[blkspade]

Will do it tonight! Thanks!