Scott_S.

I'm trying to setup dual rates on my DX7 but can't get enough servo/flying surface movement to even make it worthwhile.

Plane is a Twist 40 ARF, I mounted the Hangar 9 digital angle meter on the ail, ele, and adjusted the travel down to low rates as
listed in the manual, 15 degrees on elevator and 18 on ailerons. I have the travel down to about 45 and 50 percent to get these rates.

But when setting up the high rates the max is 125 % and the math is correct as I can go from 16 degrees on the elevator and flip the
switch and she hits 20 degrees which is 125% of my low rate setting. Problem is this is a small amount.

The manual states 15 low and 28 high on the elevator and even go as high as 35 degrees for 3D.

Expo is no problem, works just like the manual says.

I could get these high rates before at the default setting of 100% in the travel menu but I had to back them way down
to get low rates which I will need for sure. (my second plane)

I adjusted the travel down on the main travel screen where you can select any servo and up and down travel amount.

Any help is greatly appreciated. I'm a little confused because guys at the club have huge control surface changes in going from
low to high rates, but the DX7 only goes to 125%. Thanks

Scott_S.

Guys, take a look at this screen shot under : Single Screen Dual Rate-Exponential

at this link: http://www.horizonhobby.co.uk/aeroon...e6dx7/e6dx7pg2.

They don't even show the travel adjustment screen shot but show the D/R at 70% , and at 125 on high rate.
mine are all 100% on this screen. Do you adjust servo travel at this screen or
the main travel screen? It's confusing the way I write, if no answers I'll call Horizon tomorrow.

Thanks!

rhd-RCU

My Feedback: (36)

Set your travel in travel adjust. In dual rate and expo mode you adjust the percent of this travel. From 100% down to 0 %.

BuschBarber

My Feedback: (2)

Set your Travel Adjust to the max (125%) and then use Dual Rates to lower it if you need to. The Dual Rate is a percentage of the Total Travel Volume. Be sure you set the Expo to a Positive number, for JR/Spektrum. The higher the number, the softer the Neutral. If you use Negative Expo, you get the opposite effect.

Futaba uses Negative numbers, for Expo, to get a softer Neutral..

Scott_S.

Thanks guys, that explains it. The first thing I did was to lower the total travel adjust to the low rate settings thinking the DX7 would
just allow another totally new setup in the travel adjust screen under a high rate setup. Well this is not the case.

Thanks again for the explanation, this is my first setup using dual rates on the DX7.

My Rx batt is charging tonite and I'll hit it again tomorrow

rmh

The guys who write the manuals, have a heck of a job - to get enough info for everyone -but in 40 pages (so to speak.)
This kind of question would not occur to someone who had a background in radios but for recent comers, makes perfect sense.
Computer IT's have a thousand stories about how new technologies and their instructions often don't fit together.

Scott_S.

I got it! After getting it all setup it makes perfect sense to me now.
What threw me was I thought the Travel Adjust screen would allow a complete new set of instructions
for each servo under another rate.

I still have ailerons screwed up, I'm getting 17 degrees on up but 23 degrees on down. I don't see any way to
correct it.

I went to 125% max on all surfaces and backed down the percent under Dual rates for the low side. I'm down low as
40% on some settings to get the low rate.

Thanks

BuschBarber

My Feedback: (2)

Make sure, in Travel Adjust, you are setting the values for both Up and Down or Right and Left. You have to move the stick and set the numbers accordingly.

bjor

Also - set all you sub trims to 0 and mechanically adjust the servo horn to be neutral to the control surface.

Scott_S.

Got both those, sub trims at zero (default) and both travels on each servo.

My ailerons are down too much. Moving the servo arm another notch is too much.
I'm using a Y connector. If I went to two channels (one servo in each wing), would it allow me to
adjust the travel on each servo in both directions like the elevator or rudder?
One would have to go to an aux channel, I'm using my new DX7 and AR7000 RX.

Thanks.

rhd-RCU

My Feedback: (36)

Date 10/9/2008 7:13:39 PM
Also - set all you sub trims to 0 and mechanically adjust the servo horn to be neutral to the control surface

This is impossible with some servos. Get it as close as you can mechanically than use sub trim. That is what it is for. Years ago you could center the servo by moving the pot.

BuschBarber

My Feedback: (2)

If you are using servo arms that have more than one section, remove the arm, rotate to the next section, and push the arm back on the spline. Try this with each section of the arm as some sections of a servo arm may end up being closer to neutral and require less SubTrim adjustment.

rmh

On the JR arms rotating the plastic arm "180 degrees is not quite 180- as the number of splines does not permit this
- if the radio is at zero trim- there is always a position where two of the plastic arms -(one on each servo) will align
This is not true for the aluminum arms . on those - I have one double aluminum arm -which I have removed one sid-so that this particular arm has the spline in a slightly different position.. It then makes a match when used as paired aileron arms.
On th elevators this same condition exists - -again rotate arms 180 to get a match.
I rarely -if ever -use any subtrims for matching
I do use it on single functions tho. particularly rudder. on foamies ..

Scott_S.

My mistake was I used the Dubro extra strength and extra length because I thought I needed the length to
get max throws. Thus........I installed the aileron horns in line with these.
Problem is........they are so long nothing else will allow the clevis to work freely. It binds up. Can't use shorter arms.

I'm building Mojo this winter, I'll spend 200 friggin bucks to buy the best and more importantly easier
hardware to install. I fought that H9 throttle steel rod crap that came with the Twist and for two full
evenings and it was pathetic and never right. One trip to Hobbytown, grabbed a Sullivan semi-rigid throttle
cable that came with real brass clevis (2) retainers and crimp on threaded end rods. In about 10 minutes
I had it setup perfect, all while absolutely smooth operation. All for a measley 7 bucks.

TedMo

Please explain why you can't use shorter arms, just move the horns. If you are getting more throw in one direction than in the other you either have horns improperly mounted or servo arm not centered.

Scott_S.

Ted, this is my balsa/monocoat/fuel build of any kind. I built two depron pusher jets prior to this.

The Dubro arms are so long and now the aileron horns are lined up with these long arms, I can't go any shorter
because it binds the plastic clevis very tight. I could move the horns in but thats three more holes in fairly close
proximity to the others, might make it weak, might not.

I went ahead and made up shorter push rods. I've learned alot in this build. Number one: check for servo arms to be 90 degrees out.
The darned Dubros are off half a tooth and I checked on all five brand new DS821s.

Also Ted, my biggest mistake in this build was NOT having the ailerons in the neutral position. They appeared to be in neutral while
I was drilling and CAing things in place, but the Twist wing is so fat it threw me off about 1/4 inch and then when I buttoned everything
together......my troubles began. All's good now! Live and learn.

Thanks for all input guys!