EXPONENTIAL HUH?
12-26-2005, 10:08 AM
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EXPONENTIAL HUH?
Hey Guys-
I know this may be a VERY SIMPLE term. But I Just Do NOT Know what it means. "EXPONENTIAL"...I have heard it in reference to wing control setup. Im assuming it is used in describing aileron operation? Ive looked several places for a description for the word in terms of RC airplanes, and have found nothing. SO would One of you fine educated Gents out there Kindly explain in detail just what this means?...LOL....I'd really appreciate it.
Thanks
DV
I know this may be a VERY SIMPLE term. But I Just Do NOT Know what it means. "EXPONENTIAL"...I have heard it in reference to wing control setup. Im assuming it is used in describing aileron operation? Ive looked several places for a description for the word in terms of RC airplanes, and have found nothing. SO would One of you fine educated Gents out there Kindly explain in detail just what this means?...LOL....I'd really appreciate it.
Thanks
DV
12-26-2005, 12:37 PM
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RE: EXPONENTIAL HUH?
Expo controls the sensitivity of your control sticks.
Negative expo will make the reaction of the controls less jittery.
What it does is slow down the reaction if you will, instead of the control surface reacting exactly to the control stick inputs, they do not move quite as much as the stick on initial movement, but they do increase as the stick is moved even more. You still have full movement of the control surface but it's not related to stick movement.
As an example, with no expo, stick movement of 1/8 stick travel will equal a 1/8 movement of the servo arm to the control surface, 1/4 stick = 1/4 movement.
Now as expo is adjustable, it will vary, but just to give you an idea. Neg expo: 1/8 stick travel could equal only 1/32 of servo arm movement, 1/4 stick = 1/8 servo movement, 1/2 stick = 1/2 servo, and so on.
Reaction with expo will progressively increase in relation to the stick movement.
Negative expo will make the reaction of the controls less jittery.
What it does is slow down the reaction if you will, instead of the control surface reacting exactly to the control stick inputs, they do not move quite as much as the stick on initial movement, but they do increase as the stick is moved even more. You still have full movement of the control surface but it's not related to stick movement.
As an example, with no expo, stick movement of 1/8 stick travel will equal a 1/8 movement of the servo arm to the control surface, 1/4 stick = 1/4 movement.
Now as expo is adjustable, it will vary, but just to give you an idea. Neg expo: 1/8 stick travel could equal only 1/32 of servo arm movement, 1/4 stick = 1/8 servo movement, 1/2 stick = 1/2 servo, and so on.
Reaction with expo will progressively increase in relation to the stick movement.
12-26-2005, 12:43 PM
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RE: EXPONENTIAL HUH?
This is true for Futaba.
JR uses Positive Expo to do the same thing.
JR uses Positive Expo to do the same thing.
ORIGINAL: Glacier Girl
Expo controls the sensitivity of your control sticks.
Negative expo will make the reaction of the controls less jittery.
What it does is slow down the reaction if you will, instead of the control surface reacting exactly to the control stick inputs, they do not move quite as much as the stick on initial movement, but they do increase as the stick is moved even more. You still have full movement of the control surface but it's not related to stick movement.
As an example, with no expo, stick movement of 1/8 stick travel will equal a 1/8 movement of the servo arm to the control surface, 1/4 stick = 1/4 movement.
Now as expo is adjustable, it will vary, but just to give you an idea. Neg expo: 1/8 stick travel could equal only 1/32 of servo arm movement, 1/4 stick = 1/8 servo movement, 1/2 stick = 1/2 servo, and so on.
Reaction with expo will progressively increase in relation to the stick movement.
Expo controls the sensitivity of your control sticks.
Negative expo will make the reaction of the controls less jittery.
What it does is slow down the reaction if you will, instead of the control surface reacting exactly to the control stick inputs, they do not move quite as much as the stick on initial movement, but they do increase as the stick is moved even more. You still have full movement of the control surface but it's not related to stick movement.
As an example, with no expo, stick movement of 1/8 stick travel will equal a 1/8 movement of the servo arm to the control surface, 1/4 stick = 1/4 movement.
Now as expo is adjustable, it will vary, but just to give you an idea. Neg expo: 1/8 stick travel could equal only 1/32 of servo arm movement, 1/4 stick = 1/8 servo movement, 1/2 stick = 1/2 servo, and so on.
Reaction with expo will progressively increase in relation to the stick movement.
12-26-2005, 08:47 PM
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RE: EXPONENTIAL HUH?
There is one other thing that most newbies don't realize about the rotary output servos that come with todays radios. They actually have more movement around center than they do further out on the movement because as the stick is first moved the movement of the pushrod is very linear but as the arm moves further the arcing motion takes away some of the movement at the control surface. This is caused be good old geometry and we are stuck with it. So you actually have reverse exponential (more sensitive around center). This is just what you don't want. According to the instruction manual of the Futaba 9Z WC2 adding -16% (on Futaba) equals true linear movement throughout the entire swing of the servo arm.
In the "Good Old Days" of RC servos had linear output racks that the pushrod attached to which moved back and forth in a straight line so you always had True Linear movement. Of course you had no adjustment of travel or reverse so we are still way better off today. Adding exponential will make any aircraft fly less twitchy and more smooth to control inputs. Try some just remember on JR it is Positive and on Futaba it is Negative.
Hope this is some help explaining this.
Mad Man Marko
In the "Good Old Days" of RC servos had linear output racks that the pushrod attached to which moved back and forth in a straight line so you always had True Linear movement. Of course you had no adjustment of travel or reverse so we are still way better off today. Adding exponential will make any aircraft fly less twitchy and more smooth to control inputs. Try some just remember on JR it is Positive and on Futaba it is Negative.
Hope this is some help explaining this.
Mad Man Marko
