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How to trim the plane after a flight?

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How to trim the plane after a flight?

Old 07-04-2015, 12:42 PM
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Jack_K
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Default How to trim the plane after a flight?

After I have flown the plane and set the trims, if I change to a different model the trim settings in the TX are lost because the TX (DX6i) does not save the trims.

I'd like to change the linkages on the plane to compensate for the trim settings in the TX. So, how do I measure the trim amount and then adjust the linkages so I can use the zero trim on the TX?

Jack
Old 07-04-2015, 01:08 PM
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red head
 
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I don't use 2.4 or digetel ( sp) settings. all mine are the old 72 's but as I remember I adjusted 1 turn for each mark on the trans. then test flew and made another adj. if needed . I think you could probably use 1 turn for every 3 clicks on the trim tab. Seems like I used that for a couple students at one time. Just be sure to test after an adj. so you don't have a major problem the next time you fly . ENJOY !!! RED
Old 07-04-2015, 01:11 PM
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Square Nozzle
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Jack, my method (and I'm sure many others) is to leave the trims in the as flown condition and measure all the control surface positions. Once I have recorded the trimmed locations of the flight surfaces I return the transmitter trim levers to center. Now I adjust the control surface push rods to place the control surfaces in the as recorded positions. If you measured correctly the newly trimmed plane should fly straight and level with the transmitter trims in neutral.
Old 07-04-2015, 04:16 PM
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jester_s1
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A DX6i will save the trim and end point settings. Are you sure that's what you have?
Old 07-04-2015, 05:12 PM
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Jack_K
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Originally Posted by jester_s1 View Post
A DX6i will save the trim and end point settings. Are you sure that's what you have?
Spektrum told me the DX6i does not store the trim settings. They said I should use the sub trim.
Old 07-04-2015, 07:45 PM
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jester_s1
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Well it does. Your manual will give you the details. IIRC, the DX6i has digital trims which will be saved automatically when you turn off the radio.
Old 07-05-2015, 06:22 AM
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Jack_K
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Originally Posted by jester_s1 View Post
Well it does. Your manual will give you the details. IIRC, the DX6i has digital trims which will be saved automatically when you turn off the radio.
Yes, it stores the trims. But, when I select a different model, the trims for that model are stored and the previous model's trims are lost.
Old 07-05-2015, 12:03 PM
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So , just set the trims up mechanically with the trans trims in the center then you don't have to worry bout it . That's the way they should be set anyway so you don't have problems later. OLD SCHOOL !!!! ENJOY !!! RED
Old 07-05-2015, 01:25 PM
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Jack_K
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OK. I just tried it on the bench and it seems to store the trims in the model. Switching to a different model and changing the trims and back to 1st model, the trims I saved seem to be there.

Now, how do I zero the trims? I don't hear any beeps when I move the trim all the way back and forth.
Old 07-05-2015, 01:55 PM
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I'm not up on your transmitter but most have the beeps ( you didn't hear ) and you just count them from the bottom up and split the difference . Others have a sliding scale somewhere on the screen that shows where your trim is set. Older ones just have marks along side the trim lever and you just center the lever .
Now to clarify something I hope . Once you set the controls ( elev, rud etc. ) you need to set the trim lever in the center and test fly the plane again to be sure you have the setting right for that plane . Then if you are flying a different plane on the same transmitter you have to go through it all over agin with the next plane . It takes time to do it right but in the long run it will pay off especially if all directions are set the same on all planes . NOT much chance of reversed controls .
I have a lot of the older systems that don't allow more then 1 model to a trans. By setting them up this way I have 4, & 5 planes on the same Transmitter , again OLD SCHOOL lol Hope this helps . Oh ya ~~ minor trim adjustments may be needed for each different flight, just put the trim back to center the next time . ENJOY !!! RED
Old 07-06-2015, 08:27 AM
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Hi!
I have the same radio that you have and it saves all trim settings automaticly. Same as every other modern radio does.

After the first flight when you have trimmed the plane you probably don't have the Cof G correct so you have to ask yourself : Is it tail heavy or nose heavy?
If it's tail heavy the plane is very sensitive on elevator. If nose heavy the plane requires lots of levator throw and dives slightly when you throttle down and fly straight.

Neither of these trim situations are good! So after the first flight trim the plane by moving the batteri /servos untill the plane flies good.
Good means using as little elevator throw as possible (means moving the Cof G backward) but still having a agile plane that can do every maneuver in the book!
One allways trim a plane as far back as possible! That way you can use as little elevtaor throw as possible and still have agile airplane that is very easy to fly.

You most also trim the plane by adjusting the clevesis. Do not fall into the trap many newcomers do by just adjusting the trim on the transmitter, that's not the way of doing it!
You can go in and check the trim settings on your transmitters display so that the trim positions could be centered (remember to djust the clevesis after that) . That way you are certain that you have enough trim in both directions.

Last edited by jaka; 07-06-2015 at 08:31 AM.
Old 07-06-2015, 12:34 PM
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Jack_K
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Originally Posted by jaka View Post
Hi!
I have the same radio that you have and it saves all trim settings automaticly. Same as every other modern radio does.

After the first flight when you have trimmed the plane you probably don't have the Cof G correct so you have to ask yourself : Is it tail heavy or nose heavy?
If it's tail heavy the plane is very sensitive on elevator. If nose heavy the plane requires lots of levator throw and dives slightly when you throttle down and fly straight.

Neither of these trim situations are good! So after the first flight trim the plane by moving the batteri /servos untill the plane flies good.
Good means using as little elevator throw as possible (means moving the Cof G backward) but still having a agile plane that can do every maneuver in the book!
One allways trim a plane as far back as possible! That way you can use as little elevtaor throw as possible and still have agile airplane that is very easy to fly.

You most also trim the plane by adjusting the clevesis. Do not fall into the trap many newcomers do by just adjusting the trim on the transmitter, that's not the way of doing it!
You can go in and check the trim settings on your transmitters display so that the trim positions could be centered (remember to djust the clevesis after that) . That way you are certain that you have enough trim in both directions.
Good response. Thanks
Old 07-08-2015, 07:39 AM
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jester_s1
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The DX6i has a scale on the display screen to show you where the trim setting is. I don't worry about it being a bit off center. It makes zero difference in how the model flies. That's what digital trims are for after all, to let you set the trim easily and not need to worry about it. I don't like having it way over to one side because that means you might not have enough trim adjustment left if something changes on your plane such as a CG adjustment. A big change done with trims also can mean that your servo arm is not square at the neutral setting, which in some setups will cause you to get more throw in one direction than the other.

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