bubba

A huge factor in the scheme of things is where the center of the surface travel arc occurs, unless you center the servo/arm in this location everything else is a moot consideration... For those that find favor with aligning the servo arm 90 degrees or perpendicular at neutral to the servo case/body, hinge-line whatever you'll find the need to use different ATV percentages to realize equal throw in almost every case...

Michael,

You are correct and the videos I suggested actually cover this. My apologies for not being more accurate on that and probably some other points.

BTW, I did order the linkage "software" and read over the info on the web site. I can't wait to get it and dig into it. It looks like it will make life loads easier on setups, especially when trying to decide servo arm length, control horn height, etc...

The software is a real time saver for mock setups for sure. I have found many a problem for modelers with same, the key is accurate measurements. It’s very easy to see how bad many model setups really are, simply plug in some numbers and its all in front of you in black and white. The ideal linkage configuration can be had with any model by simply inputting the physical characteristics of said model and installing the control arms (servo position where applicable) where it best suits the model specific needs.

Envision also has several design programs for those that like to experiment with model design.

You guys have really done a nice job in the last 20 or so posts of making what we were saying earlier on even clearer. Thanks for the discusion. Bob its great to see you got the hang of using the programmer quickly. I had a feeling you would not be disappointed!

RVM... just for the record. You say earlier that if not for the programmer you would use Hitecs. Im not trying to sell you Hitecs but you do not NECESSARILY have to have the programmer to utilize their servos. Off of the shelf without being programmed they are fantastic servos especially the 5955TG's.

They are just better than the rest by a onlg shot WITH the programmer because as M Glavin said you can program the centers of the servos to be centered in line with the travel arc of the control surface which is the ONLY way to get true linearity and then you can program the endpoints so that you can use 100% of the resolution of your transmitter.

Michael,

I actually bought both of the software options after looking at them both with electronic delivery and he was kind enough to give me the cost as if I would have bought both at the same time. I had them within an hour and was up WAY past my bed time playing with them. They look complicated at first until you start playing around and then it becomes pretty clear.

MikeEast, I've been slowly replacing all my 5945's Hitec's with the 5955's. So far I have done my Ultimate and Cap and while WAY overkill for both, what a huge difference, especially the rudder. Pinwheels on both planes are now easy to do and KE loops are a breeze as well and I no longer need to replace gearsets after 75 to 100 flights.

RVM, MikeEast is correct. you do not need the programmer and I did not have one for a little while, then I was at a meet where someone was replacing a servo and using his programmer so I watched just how easy it was to reverse the servo direction and setup the servo travel and I was hooked. It does seem overwhelming at first but having the ability to reverse a servo is worth every penny this thing costs not including all the other things you can easily do.

You misunderstand my friend! I said I would use Hitecs just because they have the programmer!

Now THAT's what I'm talking about.... the benefit of the programmer was NOT "obvious" to me, until I USED one.... now, I'm almost a militant-convert to it's benefits and use of the 5955TG servo. A tough combo to improve on, in my experience (so far)

Oopps, sorry

Ok Im gonna revive this thread for a minute..I read the RCU article about setting up dual elevators..just want to be clear about the process..You install the servo in the tail...tape the protractor to the fuse side and line up the center of the servo output shaft with the zero on the protractor..then put the servo arm on and manually line it up with the 90 deg mark on the protractor..clamp the elevator half so it is neutral, install linkage and adjust accordingly until the servo is holding the elevator neutral..next MANUALLY move the servo arm/elevator half to your desired max throw..say 60 deg..mark this and repeat in the opposite direction..ok now my question....If I find that my linkage is only giving me 45 deg and I want 60 I would adjust the linkage manually to get the desired throw right ? now won't this throw off the neutral point that I set up previously ?

All the above should be done before the servo is powered up/programmed correct ?

Not quite.

Tape the protractor on and have it's center in line with the output shaft, not the arm. Connect everything including the control rod and turn it on. Get the servo arm as close to center as possible but do not worry about where the surface is at this time.

Now move the surface using the radio in both direction and see if the servo arm is moving the exact same number of degrees. Adjust the control horn height and control rod length until it does, again, not worrying about whether the surface is centered or not.

Once you have it moving the same amount of degree's in both directions, then your mechanical geometry is perfect.

Now program the servo to center the surface. Once you have that move the protractor so that it's center now matches up with the servo arm and then adjust your endpoints so that you get the exact same amount of throw on the surface in both directions. Once you have this, then you should also still be getting the same amount of degrees on the arm in both directions.

When you are all done, the servo arm most likely will not be exactly perpendicular to the servo case but you will be getting the exact same amount of throw and most important of all the servo takes exactly the same amount of time to get that throw in either direction.

If the servo only move 35 degrees in one direct to get the surface to 45 degrees but moves 40 degrees in the other direction to get the surface to the same 45 degrees the speed will be slower when the arm is moving 40 degrees versus 35 degrees and if you are working on the ailerons then your rolls will not be axial and on the elevators, the faster side will cause the plane to roll to that side

So although Im not concerened with the surface being centered, I should adjust to be close but in the end, I will use the programmer to set the final position correct ? Also this is before any programming is done to the servo and everything on the TX is at zero ?

At this point, I am measuring the servo arm movement on the protractor..not the actual surface right ?



AH HA!! that was the part that was not making sense to me! Im thinking the arm has to be 90 deg to the servo at all times..

Yes, yes and set the trims to neutral and end points to somewhere around 130%

Yep

The main reason why you seem to be reseting the surface travel is because as soon as you reset the center on the programmer, the end points are lost and must be reset.

Once you do it the first time it will all become clear.

It also works for multiple servos on the same surface. It takes a bit of work but you are treated to a very well flying plane

OK I got it now! Thanks!

Bubba..I was reading this in the How-To section and came across this section..when he says to MANUALLY move the servo arm, he means actually taking the arm off the servo and aligining it at the 90 deg mark ? I was under the impression that this is not always possible ?

Geometry Step Three:

In order to get the symmetry perfect, the linkages must be identical in length, alignment and travel. This takes a few tricks but is easily accomplished with a paper protractor and a good eye. To correctly set up the linkage the servo must be installed in the airplane and a protractor mounted to the airframe in such a manner as to allow the servo arm center to be in line with the center of the protractor. Ideally, the center point of the protractor will be the center line of the servo arm pivot point (see figure 5).

Simply cut out the protractor and align its center where the servo arm pivot point is and use tape to hold it in place. Do this on both servos. The orientation of the servo is unimportant, the only thing that needs to happen here is that the protractor 90* mark needs to be perpendicular to the control direction (nose-tail in this example) Once the protractors are installed, the servo arm is moved manually to the 90 degree mark (see figure 5).

Note : it is unimportant at this time whether the servo is centered so do not use the radio to perform this step - move the servo arm manually and don't worry about electrical center.