Elevator Mis-match

[Flatlandman]

I prefer the matchbox set up rather than programing a servo.

[yakpilot]

Using a matchbox is usually quicker and easier, but if you want the servos to be in sync through their entire travel you have to program them. I've used matchboxs many times and they work well to set end points and centering, but often times you can't get the servos to match in the in-between points where they spend most of their time while in flight. Of course there are variables. If you've optimized the linkages and start off with servos that happen to match well then you are golden. But I've had servos the that were not matched very well from the factory, and once you start changing subtrims and endpoints by very much, you will get one servo that moves farther than the other for a given stick deflection. Anyways thats been my experience.

[blackbeer]

Well I used an EQ2 once on a 7C to get both elevator servos in sync but it put out so much noise I could barely get a ground check with that radio so I'm not ready to go that route again. Maybe I will need to break down and get a programmer but I wonder if that will overcome the difference in resalution between the channels in my radio.....................

Tom

[yakpilot]

Tom yes it would since you can then just use a Y harness and run them off of one channel.

[3D-Seth]

	Quote: Originally Posted by scott m lyons
	Seth with your setup wouldn't that mean if the servo was in the stab you would have to tilt the arm back?You could just flip the servo to the top meaning in the stab and the end of the servo arm were the linkage connects would be the same distance from the stab.I'm trying to make sence of it because I always setup my stuff like extra260 does and my stuff is always the same length and square.My end points are the same also meaning up is the same as down.I don't program the servos i do it in the radio and match-em.

No, Unless you mean parallel to the hinge line. Because the servo is rotated 90º

With the fuse mounted elevator servos, in the bottom portion of the drawing (incorrect way, mounting the servo arm 90º to the case), the arm and linkage straightens out very quickly, ending your travel, which differs from when it is pulled away from the horn, which pulls more throw much faster. Basically, you have 30º of up elevator, with 70º of down elevator (just random numbers), but yet in the same amount of time.

Basically, the same reasoning as to why your linkage isn't 90º to your servo arm on your wing mounted aileron servos, or stab mounted elevator servos. More travel.

Basically, its just offset to equal your travel in the same amount of time between your up/down throw.

Hope this makes sense.

Seth

[scott m lyons]

No y harness in giant planes.Or any plane for that matter if you can help it.

[blackbeer]

Ya, I'm not into Y harnesses at all. Been there, done that. I just went over to Servo City's site and there seem to be 3 different programmers with a huge difference in price. Could some one clue me in on which one to get. The one that is over 150 bucks is out for now but if one of the others would program my 5945s and 7955s I might be able to swing it.

Tom

[scott m lyons]

I Think we're miss understanding each other maybe? I mean like this.

[yakpilot]

	Quote: Originally Posted by scott m lyons
	No y harness in giant planes.Or any plane for that matter if you can help it.

If they are heavy gauge, why not? BTW we are not talking about 43% Carden here. For a 50cc it's just fine.

[scott m lyons]

I do think they make y's that will handle the amps.But if you bind or lose one servo the likely hood of the other one going is very high.Just alittle bit of safety.Exspacially when the radio WILL do split elivators he just has to work on it some more.Dude don't give up till you figure it out.I wouldn't use match boxxess either.Remember weight plus money??You don't need them.Spend the time to figure it out .Go over the setup again.It will make future setups go easier and you'll learn how to do it right.Which is most important.

[3D-Seth]

	Quote: Originally Posted by scott m lyons
	I Think we're miss understanding each other maybe? I mean like this.

Right...

The linkage will straighten out faster when up elevator is given. Giving you less throw.

Which is why you offset it forward like I showed...

[1bwana1]

OK, I have been following this thread and we are not getting to far answering the question. My perspective is this. I have set up planes successfully using all of the methods discussed on this thread. However, you bought very good Hitec PROGRAMABLE SERVOS. You should be able to use them to set up your plane properly. I have used them in two ways.

The first way is the method taught by Joe Hunt in the following videos. It takes some fiddling, but works great.

link to video #1 http://www.flyinggiants.com/gallery/...hp?photo=56318

link to video #2 http://www.flyinggiants.com/gallery/...hp?photo=56320

link to video#3 http://www.flyinggiants.com/gallery/...hp?photo=56321

The second is to use the programming to get the servos matched perfectly. To do this, I program them using Joe Hunts method off the plane using a protractor as described in this article:

http://www.rcuniverse.com/magazine/a...article_id=486

To make it super easy, you can buy one of these:
http://www.servocity.com/html/servo_protractor.html


I then tweak the physical setup to get them matching perfectly on the plane.

If you really think your radio is causing you the problem, don't use a mix, run both elevators out of the ELE channel through a "Y" harness. If you are using a good quality twisted servo extension, the wire is not the problem with a "Y", it is the connector. Just make a "Y" using a Deans 3 pin connector:

http://www.hobbypeople.net/gallery/625083.asp

It will easily handle the power to feed two servos, cheap, and you only need one.

Honestly, you won't program that much, so buying the Hitech programmer may not be cost effective. I have one, and share it locally with my fellow flyers. I'm betting someone in your area has one he would share as well.

I have been able to easily achieve perfect setups without using Sub Trims or other radio programming on my and fellow fliers planes.

Hope you find these links useful.