RunRyder - How much expo?

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Aerobatic 3D Contest > How much expo?

skwarwheels
Heliman
Location: Newark, Ca

Hi,

I was just wondering how much expo you guys use for 3D. I read in CY's book that most don't use any. What I'm finding is that some banked turns become real quick all of a sudden when I run expo (30%). What I was thinking was a dual switch, one with expo for hovering, and then another without.

Thanks for any input!
Michael

01-15-2003 Over year old.

Obsessive
Key Veteran
Location: 41.73N 71.41W

Are you using the "right" expo?

On a JR radio, positive expo decreases sensitivity around center, (what you want).

On a Futaba radio, positive expo increases sensitivity (likely you don't want that).

01-15-2003 Over year old.

HOMEPAGE

a_korandr
Veteran
Location: Chicago, IL

i personally believe EXPos are bad - they reduce the precision, especially with PCM1024.

imagine your servo full ATV is 1024 points. If it was linear conrol at 1/8 of a stick you would use 128 points. However if you use significant EXP you may use only, say 80 points.

Now all of the servos need to move a few degrees (seconds) before they develop their power (torque). Digitals neeed less than analog ones. Let's assume a servo need -/+ 10 points to hold its position steady at 1/8 stick.

So in case of no EXP you have 128 -/+ 10 points, in case of using EXP you have you servo holding position at 80 -/+ 10 points. So persentage vise you loosing precision of your control and make your servo work harder...

If you need to soften your controls do it mechanically...

My 0.02c.

01-16-2003 Over year old.

deadfish
Senior Heliman
Location: Taipei, Taiwan

Andrey

Personaly, I would not agree with your point that using exp makes servos working hard.

My point is that servos all affect by outside forces (maybe except throttle servo). Just image that you disconnect servo arms (ail, ele) and rotate the main rotor head and then you would see servo arms will move because they take force from outside.

If my point is right, then even you don't give any control input, servos still need to correct their own position (this is the reason why digital servos BIZZ all the time.). So there is not much differences because of using EXP.

01-16-2003 Over year old.

a_korandr
Veteran
Location: Chicago, IL

Jesse,
may be this article can help to elaborate on my view :
http://www.futaba-rc.com/servos/digitalservos.pdf

cheers,

01-17-2003 Over year old.

Rotor
Key Veteran
Location: USA

35%..

My motto is this..Fly...Rebuild...Fly

01-17-2003 Over year old.

Heli-Driver
Elite Veteran
Location: Arlington, TX

On my Fury with 9252's I run -20% expo (Futaba). Otherwise it is simply too sensitive around hover.

I don't see how running expo will affect servo performance or it's life, maybe I missed something?

Raymond

Predator Gasser SE/231 X 2
Century Helicopters

01-17-2003 Over year old.

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skwarwheels
Heliman
Location: Newark, Ca

Hi,

I just wanted to thank everyone that has been replying to my Topic. I'm not sure what the etiquette is for acknowledging other's contributions here, but thank you just the same. I have been following each and every one!

I have been experimenting with zero expo. The cyclic's weren't too bad to get used to, but the tail rotor was really fast. I'm talking sneeze and do a U turn fast. Very much scary for me!

So zero expo on the cyclic's and 20% or so is working "okay". I keep wanting to go back to some expo to smooth things out. Where I'm really struggling with this is in moderately fast, to fast backwards flight. What I'm noticing is that the heli continues to roll in the middle of the turn. One way it rolls out of the turn in the middle and on the other it roll into the turn and basically rolls over. This leads to an instantanious need to regain orientation because the heli is now doing something that I didn't want it to do. Not fun! Lowering the expo has allowed me to control this much better but after a few turns, especially inverted tail first...my nerves are frazzled! So maybe I'm barking up the wrong tree, looking at expo to correct another problem.

I don't want to change the "flavor" of this topic, but any insight from other pilots would be greatly apprieciated!

Thank's again for all the great information!
Michael

01-17-2003 Over year old.

beast
Veteran
Location: Laurel MD

Paddle weight and design is also a big part of the equation. i myself run 20% expo with the white fury paddles at first it was kinda fast but now it's like gravy your brain will adjust to it. it's a matter of preference like chevy or ford but go with what you like experiment with different paddle weights and different values and stick with the one you like. on the tail issue if you are running HH you adjust tail speed by afr on futaba and atv on jr also remember the lower your gains are the faster the tail will be here again you have to experiment with different values. What setup are you running?

.Beresford

01-17-2003 Over year old.

Geo
Senior Heliman
Location: Australia

Expo

Strike a happy medium say 20%
You want to desensetise for say backwards inverted circuits but you want respose for Tick Tocks
But I think Collective power and speed is a must
easier said than done
Geo

01-23-2003 Over year old.

greger
Senior Heliman
Location: vancouver, WA

I use my dual rates for dual expo... full travel at both 10% in soft mode and 5% in full mode.

01-24-2003 Over year old.

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Aerobatic 3D Contest > How much expo?

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