Ive been told while using JR 8611's and all digital type servos that you want to run the ATV all the way up to 140% to get full torque out of the servo. I made the mistake of getting severe flutter on a 40% Extra because I had the ATV's way down to 70% to fly sequences. So I fix it set it up and have been told to run the atv all the way to 140% and set-up the linkages for maximum mechanical advantage which I have, but now I want to tune down the throws. How do I do this without changing the geometery at the servo? Can I run my ATV's down to 100% and not loose to much torque? Im sure I could I just dont want to see this thing flutter in again. Carden Extra 330 40% with dual 8611's on each elevator.

Thanks,

Pete

Anyone out there with a set-up for a 40% Carden 330. I would reallyu appreciate a place to start with the set-up.

ON my Carden 330 I have one 8611A on each half. I setup the ATV at 140% on the 10X radio. full up and down deflection is 20 degree of throw. I used dual rate to set my low rate.

I also added 3/4 of lead to the counter balance of the elevator(advise received from Ivan Kristensen). This setup was worked great.

I didn't think the ATV had anything to do with torque. I thought only the mechanical aspect would affect the torque. I understand that it does effect servo's resolution. But, I could see where this would lead to lower torque, by haveing a bad mechanical advantage and using the radio to turn them down instead of the setting up the mechancal linkages properly.

You want to try to setup the servo mechanically so that you can set your ATV at 140. This is not to get maximum torque, its to take advantage of the maximum resolution. The way I understand it, in most systems there are 1024 steps in the resolution of the transmitter. If you setup the servo linkage so that you have to dial down the ATV to make your maximum desired throw you are proportionally reducing the resolution which makes control less precise.

It all plays into the geometry of the setup. You want to setup your geometry to get maximum mechanical advantage (torque) where you want it, for me thats the desired max throw you want on your highest rate (ATV) and be able to set yout ATV at 140. Personally I set my transmitter at 140ATV and then adjust the throw mechanics until I get the max throw I by adjusting the pushrod length and control horn/servo arm adjustments. Try to get as close in on the servo arm, and far out on the control horn as I can get it and get the throw I need.

Agree with what Mike said above. Put your ATV's at 140 and leave them there. If you want to adjust servo travel for different purposes use your rates. Almost everything in the radio works off of ATV so messing with your ATV messes with a lot of other stuff, too.

So I have set everything up at 140% ATV and I get 25 up and 26 degrees down on my elevator. Good for high rates so now my question is.

Dual 8611's on elevator.....Can I take my Dual rates down for my low rate sequence flying to get about 15deg of throw and not mess with my ATV hense not mess with my servo's resolution? Is this how you guys do it?

I am inverted mounted on the servo arm 3/4 inch from servo center and center of clevis at the control horn is exactly 1 inch off the surface on all linkages. Does this sound right. I just dont want to mess this up. I paid dearly the first time. I plan on taking Dual rates down to about 70-80% to get my IMAC rates.

Thanks,

Pete

What radio are you using? for most radios you will use dual rate to get a low travel rate.

After setting up a surface to travel thru its entire distance using 140% ATV, does reducing that travel by DUAL RATES reduce its resolution?? Or does it only reduce travel. Radio is a 9CAPSuper. How does subtrim affect servo throw? Besides retrimming the center? Does the servo throw on either side change and not stay equal with use of subtrim?

OK...

Set ATVs to 140%
Adjust mechanical setup to get the MAXIMUM throws you will ever actually fly with (about 32-35 degrees for me).
Use Dual Rates to adjust throw down for IMAC.

The whole point of this exercise is to get the control horn as long as possible and/or the servo arm as short as possible. NOTHING else will actually change the power the servo has.

You WILL get better resolution, but your servo WILL also get better leverage on the surface... this puts less load on the servo, requiring less torque.

Ideally... I look for a 1.5:1 ratio (1.5" control horn to a 1" servo arm, or thereabouts). My setup actually has a slightly better mechanical advantage than this.

I just want to make sure I have this right too. I moved ATV's to 140%, moved the rod in on the servo side and the rod out on the control horn. I am getting a little better than 1.5 to 1 advantage. If I am still getting too much throw on high rates, do you just reduce high rates until you get to the proper throw? same for low rates? Thanks!

I would move out on the control horn and in on the servo arm until I didn't have anymore room before I messed with the endpoints. Ideally you don't want to dial the ATV down until you have no more room to mechanically adjust,,, at least I dont. You should be able to get at least 125 to 140. With a Rocket City control horn setup I usually dont have any trouble getting it done mechanically so that I can leave the ATV's on the transmitter maxed out.

1) set ATV to 140%
2) Elevator Dual Rates for "HIGH" position...leave at 100%... measure the throw and match the other elevator. If this is more than you like, simply lower the Dual rate for "HIGH" until you obtain your target number
3) Elevator Dual Rates for "MID" and "LOW"...same as above.

I have used this sequence for a long time w/ no problems. I runa 1 1/4" servo arm with the linkage attached to the 2nd most outer hole (1 1/8"). I now measure from the center of the hinge line to the center of my ball link on my pushrod 1 1/8" OR MORE....but never less.

That is exactly what I was looking to hear. My high under dual rates is under 100% but my ATV is at 140%. Thanks for the help.