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Old Jan 14, 2011, 04:41 PM
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Dual rate Vs end travel adjustment??

OK, I know what both do, my question is this:
My JR9503 gives me mixes and flight modes. If I set up flight modes I have 3 settings for D/R's. Now, by default the radio at 100% gives roughly 45 degrees travel which is more than many of my planes call for on hi and lo rates. most people set ATV or end trav. adj. as their high rates or 100% of what the plane calls for, then adj. down for lo rates.

Does it matter if one chooses to adjust the high rates in D/R as opposed to adj. them in ATV??? I have been setting up hi and lo rates in D/R and leaving ATV alone, but again, is there something im missing?? My thinking was that since im always below the 45 degrees or 100% that the radios ATV defaults to, setting up both hi and lo rates in D/R is fine.

Thanks, Dave
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Old Jan 14, 2011, 05:11 PM
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Most people set ATV or end trav. adj. as their high rates or 100% of what the plane calls for, then adj. down for lo rates.
Hi Dave,

Could you rephrase that, so we're both on the same page? I'm a little confused by exactly what that means.

Thanks,

Chuck
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Old Jan 14, 2011, 05:41 PM
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Instead of reduce the SERVO TRAVEL down from 100% he's asking whats the difference from doing that compared to simply setting up HIGH rates lower then 100% to match what TRAVEL adjustments would of done..

Instead of 100% travel he needs 75% travel, what is better versus leaving travel at 100% but setting up high rate at 75% and low rates accordingly?

All I can recommend is that you need to mechanicaly setup as best as you can first then fine tune with the TX. if 100% travel is too much you can always adjust the linkage so that you leave travel and D/R high rates at 100%.

Many ways get things done. None are really wrong if its working for YOU..
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Old Jan 14, 2011, 06:54 PM
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right freechip, chuck thats it. Now I do adj. the mech adv. as best as possible but again, is there a difference in adjusting the ATV (end points via servo travel) or just fine tuning the high rates and reducing there if need be?

Does adjusting ATV also effect other mixes, rates, or would adjusting High D/R change other parameters? Trying to figure out if theres ANY pros or cons of adjusting the ATV over the dual rates.
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Old Jan 14, 2011, 07:02 PM
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is there a difference in adjusting the ATV (end points via servo travel) or just fine tuning the high rates and reducing there if need be?
The only thing I can think of as the biggest difference between using ATV and DR, is that ATV would allow you to dial in the same amount of 'up' as 'down' control surface movement; while DR doesn't.

In other words, if your control surface movement is different for total travel up vs down (for example), then DR will keep that discrepancy, whether on HIGH rates or LOW rates.
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Old Jan 14, 2011, 07:31 PM
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chuck, but i can adjust up and down percentages in D/R for hi rates even the same amount if need be.

I think if you adjust ATV than those setting differences are still there when choosing lo rates......right?
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Old Jan 14, 2011, 07:47 PM
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chuck, but i can adjust up and down percentages in D/R for hi rates even the same amount if need be.

I think if you adjust ATV than those setting differences are still there when choosing lo rates......right?
Dave,

You may very well be right on this when you say that using DR allows you to vary the up and down individually.

To be perfectly candid, I never experimented with this to verify it, since I have a very rigid method of setting up all my planes on both my DX6 and DX7 radios.

For me, it's Sub-Trim to align perfectly the elevator with the horizontal stabilizer (for instance). Then it's ATV for equal travel in each direction. Then it's DR last.
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Old Jan 14, 2011, 07:54 PM
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Chuck, do you set the subtrim and/ or servo arms to a 90 degree angle to the pushrod?

-Dave
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Old Jan 14, 2011, 08:14 PM
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Chuck, do you set the subtrim and/ or servo arms to a 90 degree angle to the pushrod?

-Dave
Hi Dave,

You know me, I tend to put aside a lot of the 'conventional' wisdom from the experts, and look at things in a realistic and practical manner.

To that end... no, I do not always set the servo arms to a 90 degree angle to the pushrods. I just popped the canopy off my latest build and noticed that the pushrods are traveling at about 85 degrees to the servo case. Can I reconfigure the servo arm (using sub-trim) to be at 90 degrees to the control rods? Yep, I sure can. So why don't I? Because if I did, and let you fly it, you would never in a million years be able to tell exactly how I set it up. And neither would 99.99% of the rest of the rc modelers in the world be able to tell that it wasn't set up 90 degrees to the control rods.

There's a point we reach early on in our hobby that we are introduced to mathematics and theory, and it all sounds good, and it's all 'proper' and correct, and it can never be shown to be 'wrong'. And therefore when guys read this 'proper' way to do things, they are amazed at the beauty of the mathematics and geometry behind it and preach to all that will listen that this is the "only" way to set things up.

And then there's me... who says BS to all that hocus pocus....

When I want to fertilize my backyard in the Spring and want to know how much fertilizer I need to buy, I don't measure the yard with a laser and attempt 6 places after the decimal point accuracy....

Chuck
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Old Jan 14, 2011, 08:24 PM
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ATVs set servo travels.
D/R sets function travels.

So they are not just two ways to attack the same problem.

If for example you have two aileron servos the D/R will do both at once, where the ATVs will have to be adjusted separately.

There are also some differences if you add mixes like flaperon for example.

Long and the short of it
- set everything up mechanically as best you can.
- then use the ATVs to get final throws over the whole range that you want. Equal up/down, left/right, etc.
- then use the D/R and expo to set up flight modes and make final throw adjustments at the field.


Pat MacKenzie
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Old Jan 14, 2011, 08:27 PM
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Here ya go Dave...

Notice in this pic I just took how the fuselage narrows down towards the tail?

The control rods run through small holes in the formers and consequently they do NOT travel in a perfectly straight line. ERGO... it is impossible to set the servo arm to a perfectly straight control rod, because the control rod bends as it passes through these holes in the formers!

I spend 99% of my time building straight and true airframes. THAT is what will make a plane fly like a homesick angel; and not servo arms that are the 'prawwwwper' 90 degrees to the control rod...

Chuck
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Old Jan 14, 2011, 08:28 PM
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Long and the short of it
- set everything up mechanically as best you can.
- then use the ATVs to get final throws over the whole range that you want. Equal up/down, left/right, etc.
- then use the D/R and expo to set up flight modes and make final throw adjustments at the field.


Pat MacKenzie
I agree with Pat 125%!!!
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Old Jan 14, 2011, 08:32 PM
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Pat, maybe its the jr9503 but trust me, I can set seperate up and down travel in D/R........I can set 3 different up and downs if I enable flight modes. All this assuming I use seperate channels foe ailerons and not a "y" does this make sense? Im thinking your assuming a "Y" connector.....
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Old Jan 14, 2011, 08:36 PM
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Dave,

Look at this pic. I spent an hour or more getting these Z Bends into the control rods so that they are lined up perfectly with the control horns. The end result is that there is absolutely no binding, or even close to binding of the rods. If you're going to obsess over anything, obsess over building and setting up your planes so that they fly correctly, and not some silly notion of having the control rods at 90 degrees to the servo arm.

Chuck
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Old Jan 14, 2011, 08:38 PM
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Originally Posted by hidaven View Post
Pat, maybe its the jr9503 but trust me, I can set seperate up and down travel in D/R........I can set 3 different up and downs if I enable flight modes. All this assuming I use seperate channels foe ailerons and not a "y" does this make sense? Im thinking your assuming a "Y" connector.....
I have 9303, so I know you have separate up and down rates in the TRVL ADJUST menu.

What I meant was that if you have two aileron servos and for whatever reason one aileron goes up a bit more than the other that will have to be fixed in the ATVs.
Once you have them both working the same then you can use the D/R, differential, etc.
So ATVs correct for individual servo geometry problems.

Pat MacKenzie
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