How often does Trim need to be set on same plane
 

My quesition is one the trim is set on a plane in your radio...Does the trim need to be messed with again for that same plane aslong as u have not crashed it and messed up the CG or alignment?
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Flyn' High, Real High

RE: How often does Trim need to be set on same plane
 

It depends on how much you want to dial in the model. Ideally a model should not need to be retrimmed, but I find that any given day I need to give a control a click of trim one way or the other long after the model is "trimmed."

That may be due to the way I'm seeing the model on that day or who knows what. It could be that climate plays a part too in that the structure may change slightly.

A lot of guys swear that nyrods change length with temperature, but I haven't noticed that models of mine using nyrods need any more or less trim than models having pull-pull controls, carbon fiber pushrods or anything else.

RE: How often does Trim need to be set on same plane
 

The first time you fly the model you should make all of the big trim adjustments. After that you may make minor adjustments depending on a variety of factors like how picky you are, the temperature, density, throttle setting, and how full the fuel tank is. I have a couple of planes that I need to adjust everytime I fly. When I take off I usually end up needing a click or two of up to account for the full fuel tank. Then as the fuel burns off I end up putting in a little bit of down. It isn't real necessary, but I'm picky that way.

If you find you have to make a big trim change between flights then you need to land. Something is wrong and you need to find out what.

RE: How often does Trim need to be set on same plane
 

Minor trim adjusts ( a click or two) is fine on each flight due to many different factor, usually climate related.

Major trim adjustments for each flight = Bad = Something is wrong.

As far as nyrods are concerned, it usually takes a pretty wide difference in temp/humidity change to see it. I replace nyrods with either golden rods or my favorite, carbon fiber, for the strength. SIG uses nyrods for a lot of their models. I own 2 SSE's and I defintely saw a difference in high stress maneuvers, mainly knife edge and lomcevaks between the nyrods and the CF rods. Nyrods do flex a little more and it seems it happens the most when it's really hot out and the plane has been sitting in the sun for a little while and especially if there is a few inch run where the rod is not inside it's tube, e.g. from the fuse to the rudder/elevator.

RE: How often does Trim need to be set on same plane
 

If the plane has twists in it, you will need to re-trim for different speeds too.

RE: How often does Trim need to be set on same plane
 

I find that coro models often need to be re-trimmed if they sit in the sun, or if they gey very cold. I assume that the wing shape & alignment is changing as the plastic expands &/or contracts

RE: How often does Trim need to be set on same plane
 

One other thing to think about is wind. Yes wind. On a clear day with a steady breeze, flying up and down the field with the wind traveling crass-wise, you may tend to trim into the wind. When you turn around, you start trimming the other way. At some point you just leave it alone and handle it the way it is. But you never know where it really should be unless it's dead still.

True, hard landings or a good chunk of sod will compress the springs in your servo-saver, and trimming while taxing may straiten it out, it will throw your rudder. When in the air, you notice the plane leaning to one side, so you trim ailerons (because you tent to think the the rudder is fine, but mostly you don't want to change the steering). So as you truck along with a smile on your face thinking that your plane is now trimmed, when in fact your control surfaces are fighting each other. You can tell this is happening when you fly slowly above in a strait line... the tail wiggles and slides a bit as it coasts along.

To me, a strait ground behavior is paramount.

RE: How often does Trim need to be set on same plane
 

other things to think about are what you use for control. if you use a pull pull system you may need to trim as the lines become stretched. If you seem to have to retrim all the time (besides small adjustments) check to make sure your controls don’t have a lot of slop in them or something has come lose or worn. Don’t use servo arms that have been drilled out for larger control rods and make sure all z bends are with 90% angles. Sometimes inexpensive servos will not center properly and will need to be constantly readjusted but should really be replaced

RE: How often does Trim need to be set on same plane
 

In addition to the great information already offered I would suggest that once you have trimmed the model that you use your control throw meter to set the adjustments mechanically and then zero your radio trims.

I certainly have found that occassionally a click or two of trim is required on previously trimmed models.

Cheers,

Colin

RE: How often does Trim need to be set on same plane
 

cambec,

That's a great idea unfortunatly with the low cost of Computer radios with EPA most of these newbies won't have a clue what you are talking about. Nor will they be capable of actually doing this correctly[:o]

RE: How often does Trim need to be set on same plane
 

The only time you should have to retrim is if you have a trainer with the wing held on by rubber bands!! If you have to retrim every time out with a bolt on wing the palne has poor built in linkage or control horns etc...

RE: How often does Trim need to be set on same plane
 

I had a Rightflyer trainer with wings held in place with rubber bands...and it NEVER needed retrimming. It did however require a little trim after I pulled it down from the tree it landed in once, hehe heh. The tree could use a little trim too :D

Jim C

RE: How often does Trim need to be set on same plane
 

Quicksand:
I have to desagree with your comments about retrimming. There are a lot of examples of why you may need to make trim corrections, but I'll sight the easiest and best example:
FUEL
The fuel tank on most models is ahead of the CG. With a full tank you need a little more up trim than with an empty tank. With my GP Ultimate for example my elevator trim at the start of the flight is 2 clicks up. At the end it is neutral. I'm picky and could live without making the adjustment, but it's there.
As I said previously, though, if you need to make big trim changes between or during a flight then something's wrong, and you're right there may be some linkage issues.