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All Forums >> RC Airplanes >> Beginners >> Expo for Newb's?
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Expo for Newb's? - 5/15/2008 8:58:01 PM   
gaRCfield


 

Posts: 786
Joined: 5/20/2008
From: Burlington, VT, USA
Status: online 		I know I'm not supposed to rely on my computer radio to help me fly until I really can fly. However it was suggested to me to use the exponential on my radio at the field. I asked if I should do it, or if I should wait until I gain some experience, and I was told to use it, and that 'everyone's doing it.'

What do you guys think?

Thanks.

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RE: Expo for Newb's? - 5/15/2008 9:03:53 PM   
BarracudaHockey



Posts: 10182
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: offline 		Why would you not want to do something to make the model fly better?

That said, I'd try 15 or 20 percent and see how you like the feel. Spectrum/JR needs positive expo, futaba needs negative to smooth out the center.

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RE: Expo for Newb's? - 5/15/2008 9:06:33 PM   
MinnFlyer



Posts: 19161
Joined: 4/22/2002
From: Willmar, MN, USA
Status: offline 		Ditto to what Andy said. Keep the percentage down to 15 or 20% and you'll be fine

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RE: Expo for Newb's? - 5/15/2008 9:07:23 PM   
gaRCfield


 

Posts: 786
Joined: 5/20/2008
From: Burlington, VT, USA
Status: online 		Thanks; I just don't want to get into relying on a radio to make me a better flier, that's all.

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RE: Expo for Newb's? - 5/15/2008 9:10:54 PM   
Osirisf16



Posts: 2606
Joined: 6/10/2007
From: Paphos, CYPRUS
Status: offline 		Em...sorry guys but what do you mean by "expo"? And what is this positive ad negative you are talking about? Oh man, i forgot everything since the last time

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RE: Expo for Newb's? - 5/15/2008 9:17:23 PM   
gaRCfield


 

Posts: 786
Joined: 5/20/2008
From: Burlington, VT, USA
Status: online 		Expo, or exponential, is a setting for the responsiveness of the radio sticks. 0% exponential means that the servo responds exactly to the input of the stick as you control it. Increasing exponential means that the sensitivity around the 'home' position of the stick is limited. As you increase the movement of the stick, you get exponentially increased response from the servo. What this does is eliminate any 'jitters' you might have, i.e. if you are using elevator and your thumb gives just a little bit of aileron, exponential will make it so the receiver didn't really see any aileron.

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RE: Expo for Newb's? - 5/15/2008 9:20:37 PM   
gboulton



Posts: 1862
Joined: 5/28/2005
From: La Vergne, TN, USA
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quote:

ORIGINAL: Osirisf16

Em...sorry guys but what do you mean by "expo"? And what is this positive ad negative you are talking about? Oh man, i forgot everything since the last time


Expo changes the 'curve' of a control surface.

At "0 expo", which is to say no expo settings, move the stick halfway, the corresponding control surface (say, elevator) will also move 50% of its total travel.

Adding positive expo (usually..there can be exceptions) will 'slow it down'. moving the stick, say, halfway, will result in, for example, only 40% of the elevator's travel. in essence, it "slows down" the responsiveness of the surfaces, and thus the plane.

Negative expo has the opposite effect....a 50% stick movement might move the surface, say, 60% of its travel...making the airplane more responsive or 'twitchier".

There is, of course, a corresponding "spike" or 'flattening" of the curve at the end. If positive expo has the elevator moving only 30% of its travel for 50% of the stick movement, then the remaining 50% of the stick movement will have to produce the last 70% of the eleveator travel...so, near max stick, the surface becomes "hyper" responsive, as it were.

Exactly how much expo translates to how much movement dampening (or increase) depends greatly on the radio.

*EDIT* Sorry, Kat...i gotta type faster.
========================

Must agree with posters above...no reason not to throw some expo in. Saying 'don't mix things until you can fly without them" is, imo, like saying "Don't fly a trainer with dihedral until you can fly a sport plane without it". Ue the tools given to you to make your experience enjoyable and successful, imo.

< Message edited by gboulton -- 5/15/2008 9:21:30 PM >

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RE: Expo for Newb's? - 5/15/2008 9:22:06 PM   
Osirisf16



Posts: 2606
Joined: 6/10/2007
From: Paphos, CYPRUS
Status: offline 		Ok, fully understand. Do the radios have that setting? Nice. I'm looking forward for a Futaba 7CH or the 9C but i can't really choose. I'm in the heli world too and i can't really know right now, so i must got some knowledge for everything. I think i'm full of heli knowledge, car no doubt and know, that's why i came here...KNOWLEDGE I must learnd ALL the basics and then go advanced

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RE: Expo for Newb's? - 5/15/2008 9:36:55 PM   
gaRCfield


 

Posts: 786
Joined: 5/20/2008
From: Burlington, VT, USA
Status: online 		Yeah it's a setting on computer radios. Something to think about (I don't know anything about heli's, so this may or may not matter) is that even if you don't need more than 7 channels, having 9 channels will allow you to mix more servos together.

< Message edited by FatOrangeKat -- 5/15/2008 9:43:59 PM >

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RE: Expo for Newb's? - 5/15/2008 9:51:44 PM   
Osirisf16



Posts: 2606
Joined: 6/10/2007
From: Paphos, CYPRUS
Status: offline 		Yeah, normally a heli wants 6 channels but i want to leave spares IF I PROCEED TO HELIS for good What do you think? The Futaba 7C 2.4 Ghz or the 9C? Telling the truth, i prefer 2.4 Ghz technology, so i think i will skip the 9C and i will go for a 10C 2.4 Ghz. The bad is that is new, so the price must hurt

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Kyosho Evolva M3 - OS VZR / Kyosho MP777 SP1 - OS Vspec / Hyper 8 - OS Vspec / Baja 5b
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RE: Expo for Newb's? - 5/15/2008 9:54:25 PM   
BarracudaHockey



Posts: 10182
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: offline 		Warning: This is a bit of high level useless info in case you care, not meant to confuse the original issue


The following assumes a FUTABA radio where Negative Expo makes the center LESS sensititive, JR/Spectrum is opposite...

@ gboulton: Actually, round servo outputs already have positive expo built in. The control surface responds more while the servo is centered than than at the extremes. About 22 percent negative expo or so acutally makes the control surface reaction, in relation to the stick movement, linear which is what I prefer.

@Osiris: if you want to fly helis get a heli radio, its easier to fly airplanes on a heli radio than vice versa. A DX7, 9C, or 9303 are all excellent choices, buy the best you can comfortably afford as a good radio will last you a long time.

@fatcat: If you paid for it, use it! Most of us don't drive automatics and go around manually shifting the gears up and down Learning how to take advantage of the features of your radio is part of learning.

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RE: Expo for Newb's? - 5/15/2008 10:00:41 PM   
Osirisf16



Posts: 2606
Joined: 6/10/2007
From: Paphos, CYPRUS
Status: offline 		Em...i already made a thread about that man, if you can, copy it there but i want more info if you can, from you and from all of you Thanks, anyway

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Kyosho Evolva M3 - OS VZR / Kyosho MP777 SP1 - OS Vspec / Hyper 8 - OS Vspec / Baja 5b
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RE: Expo for Newb's? - 5/15/2008 10:05:32 PM   
gboulton



Posts: 1862
Joined: 5/28/2005
From: La Vergne, TN, USA
Status: offline
quote:

ORIGINAL: BarracudaHockey
@ gboulton: Actually, round servo outputs already have positive expo built in. The control surface responds more while the servo is centered than than at the extremes. About 22 percent negative expo or so acutally makes the control surface reaction, in relation to the stick movement, linear which is what I prefer.


True enough. I was trying to keep it simple. Should have pointed out that i was using a generalization, however, instead of spreading inaccurate info. Good catch.


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RE: Expo for Newb's? - 5/15/2008 11:19:20 PM   
flyX


 

Posts: 435
Joined: 7/24/2007
From: el centro, CA, USA
Status: online 		well if you don't wanna rely on the Tx...just move linage closer to the center of servo.
What's suckie about that is...there's only so many holes on the servo arm.

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RE: Expo for Newb's? - 5/16/2008 3:48:30 AM   
ChuckW


 

Posts: 1600
Joined: 6/15/2006
From: Clovis, CA, USA
Status: offline 		It really depends on the plane. For a trainer, I see no need. With the throws set right, most of them are plenty docile. For a fun fly plane with monster control surfaces, on the other hand, it is almost a must for me. I know some really, really good pilots with years of experience who hate it though and refuse to use it on anything.

< Message edited by ChuckW -- 5/16/2008 3:49:38 AM >

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