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How much expo???

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Old 06-10-2007, 05:21 PM
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rc-plane
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Default How much expo???

I about about to use a dx7 for the fist time and I was wondering how much expo you use. These sticks feel more loose then my futaba so I figured I need some expo how much do you usually use?


Thanks
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Old 06-10-2007, 05:35 PM
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Default RE: How much expo???

G'day Mate,
Personally I keep away from expo as much as I can, with a new plane, I set it for conservative throws, fly on low rates, & set high rates 20 or 30% more, in case I need more control, for landing or whatever.
Then after a few flights, I decide if or how much expo I may need, but I'm not flying 3D, but I want a new plane to react to my stick inputs, when I give them, then soften with expo if needed.
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Old 06-10-2007, 06:07 PM
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Default RE: How much expo???

Since Alan is singing my song----I'll chime in.

I fly zero expo--------I've tried it but I just don't like it. All the mixes and expo's are "in my head".

But I still buy the top end radios.
Goes back to the time when the best you could buy was barely good enough----plus it is one thing 'not to use it' when you have the capability but quite another if you do not.

Like Alan, I'm not into 3D, I'm into precision aerobatics------and yes I can hover with mild rates and zero expo. : low rates on occasion too.
That is a nice single maneuver --- in a full schedule-----but I do not include it unless asked-----like I said----3D isn't one of my interests.

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Old 06-10-2007, 06:11 PM
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onewasp
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Default RE: How much expo???

Edited P.S.
rc-plane you can tighten those sticks up with the adjustments provided----see page 12 of the instructions.
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Old 06-10-2007, 07:35 PM
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chrisF test pilot
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Default RE: How much expo???

It is more of a personal preference thing. Personally I am with these guys, dont like and dont use it. Most of the guys i fly with do, one being an IMAC guy who flies with 80%. Best thing to do is what Allan suggested, start with very low throws and go from there.
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Old 06-10-2007, 08:13 PM
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Default RE: How much expo???

I have an EF Yak and Crhis put this in the manual for that plane:

Elevator 8-10 degrees no expo and 60-65 on high/3d rates
Ailerons 20 deg. 30-40 expo 65-70 on 3d rates
Rudder 20 degrees w/50 deg expo and 80-90 on 3d rates

this is just a starting poing adjust to your liking....
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Old 06-10-2007, 09:26 PM
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Default RE: How much expo???

Thanks this is the first time I have ever thought of using expo. On my other planes I just fly. I will just set the low rates to the rec. and let on of the old timers fly it first in case its to touchy. I really dont know if I want to stiffen them up one of the guys at the field let me fly his funtana 100 ( he had a dx7) and it wasnt to bad but he did say he had some expo in it. I see the debate over expo or no expo at my field all the time. I guess its just you like or you dont.

Thanks

Chris
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Old 06-10-2007, 10:35 PM
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Default RE: How much expo???

10 deg on elev and 15 on ailerons will have u were it is not touchie
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Old 06-11-2007, 05:02 AM
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Rodney
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Default RE: How much expo???

This is strictly a personal taste. Once I got used to using expo, I love it and use about 50% on all surfaces as, for me, it really smoothes out the response on all three axis.
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Old 06-11-2007, 07:43 AM
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Default RE: How much expo???

My thumbs are non linear so I use expo.
Also, if your control surface mechanism has non linear geometry, you have built in mechanical plus or minus expo.

I start with -30 low rates and -50 high (Futaba) on new aircraft and adjust.

Just make sure you use the correct polarity (JR and Futaba are reversed) or you will be getting the opposite effect you want. This mistake causes many people to try expo and decide that they do not like it.

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Old 06-11-2007, 09:03 AM
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Default RE: How much expo???

geeze -my DX7 stuf works best for me with 70% on ailerons .
and 60% on elevators .My friend's always say "it's too sensitive" when they try one of my trained birds.
To be fair - the throws and speed are like the swinging doors into a fast food kitchen--
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Old 06-11-2007, 09:04 AM
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Default RE: How much expo???

I start with 20% even on low rates. On high rates i use 30 to 40% and on the studid rates (3-d) as high as 60 to 70%. This is somthing to have to get used to, but once you get the fell for it you'll never go back. Dennis
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Old 06-11-2007, 09:31 AM
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Default RE: How much expo???

Dick,
I'm with you, I don't use "crash switches" on my sport planes, I just setup the bird with the recommended high rate (if it looks right to me) then apply expo accordingly. This way I'm never on the wrong rate of the "crash switch".
Pete
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Old 06-12-2007, 12:50 AM
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Default RE: How much expo???

I love expo, it did take me some time to get used to it after flying for years without it. I use a jr 10x now and i think it has the smoothest expo, atleast compared to my old 6exa futaba. On full throws (3d) I use 30-50% on 2nd and 3rd rate I go lower as its not needed as much, but for me invaluable at high surface deflection.
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Old 06-12-2007, 07:22 AM
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Default RE: How much expo???

Flying here at 5400ft with a DX-7, and when I am setting up a new 60 size airplane, I generally add about 15% more throw and start with -25 expo on all surfaces. During the initial day of flying, I add or subtract as I feel comfortable with.

Most of my stuff will be Tiger 60, Utter Chaos 90 (Bridi Design), BTE Delta Vortex, etc. I am a sport flyer and do no 3D flying.

Cheers-Tom
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Old 06-12-2007, 11:05 AM
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Default RE: How much expo???

minus 25% is creating a more sensitive response-------not a muted response.
Did you formerly fly Futaba?
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Old 06-12-2007, 11:07 AM
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chrisF test pilot
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Default RE: How much expo???

For expo less sensitive on Futaba is neg(-), it is opposite that on JR being pos(+).
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Old 06-12-2007, 05:40 PM
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Default RE: How much expo???

Thanks guys, I meant to say + on the expo.

Yes I also fly Futaba with XPS so one must be careful on the expo.

When I first started using my XP6102DX I used the wrong expo, sure was a little interesting for awhile.
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Old 06-13-2007, 11:09 AM
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Default RE: How much expo???

It funny, all of you guys saying you don't use expo actually are. Those who use negative expo (futaba) are creating a curve to re-introduce a linear reponse from a non-linear source (pushrod attached to servo wheel/arm)
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Old 06-14-2007, 09:58 AM
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Default RE: How much expo???


ORIGINAL: rob10000
from a non-linear source (pushrod attached to servo wheel/arm)
Maybe or maybe not.

If the distance from the pivot to the pushrod hole is the same for the servo arm and the control horn, the two non-linear effects cancel each other out and the control surface tracks the servo rotation exactly. This is because your control linkage forms a parallelogram. The control horn will remain parallel with the servo arm.

If, however, the distance for the servo arm is greater than the control horn or vice versa, you will get an expo or reverse expo effect. This is because your control linkage now forms a trapezium.
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Old 06-14-2007, 10:04 AM
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chrisF test pilot
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Default RE: How much expo???

Not always, I always setup my models to have the most linear response possible. The only excepion would be my trainer where I have golden rods that are attached to bent 4-40 rods to the rudder and elevator. Not really linear but with no more throw than they have it isnt really noticeable. On my pattern plane and Extra where the pushrods go direct from servo control horn I make sure they are very linear.

And wouldnt that mean people using it really arent, since all its doing is flattening the response not dampening it?
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