Cross trims

[iflyj3]

I have searched but can not find if the ER9X allow cross trims. I am used to flying with cross trims and find them very handy in trimming out a plane especially on its first flight. Cross trims are where the current elevator trim becomes the throttle trim and vice versa. The rudder and aileron trims are swapped. This allows you to fly (Mode 2) the plane with the right hand and trim with the left hand without having to reach across the transmitter with the left hand.
A simple yes/no switch in the radio setup section could be used to swap the trims.

Thanks

[Rob Thomson]

No idea if er9x does it...

In open9x, you have the option to set the trim sticks as inputs. This in effect allows you to setup cross trims

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[MikeB]

Cross trims are not directly available. It is actually a bit complicated to implement as the trims already have to map with the sticks depending on which mode you are using.

You may, however, implement them using mixes.
First, in each mix for which you use a stick, disable the trim.
Two ways to now get the trim you want on that channel:
1. Set up a curve as 0,0,0,0,0
add a mix, specifying the stick with the trim you want, but use the curve above. This stops the stick producing any output, but the trim is added in.

2. Use a GVAR on each channel as the input to another mix. Set the GVAR input to be the trim you want. Set the mix weight to 25%.

e.g.
CH01: +100% AIL NOTRIM
+100% RUD Curve(C1) - where curve C1 is set to 0,0,0,0,0

or:
CH01: +100% AIL NOTRIM
+25% GV1 - where GVAR1 is set to Rtm

Mike.

[Rob Thomson]

Thanks Mike...

I just checked open9x and it is even easier than I thought.

In the mix screen, you have an option as follows:

capture1.PNG (8.84 KiB) Viewed 11265 times

Selecting the ON/OFF using the arrow keys, you can scroll through a list of trim inputs to use on the mix.

capture1.PNG (8.84 KiB) Viewed 11265 times

So essentiall... under open9x. 100% cross trim support

Under er9x.. Mikes solution is probably the best.

[Flaps 30]

I use cross trims all the time in both Open9x and Er9x.

With Er9x I use the solution Mike gave with C1 set to 0,0,0,0,0

Open9x as Rob has shown is even easier in that you can select the source of the trim on the mix.

[MikeB]

I might just have overstated the case. I think I have a "CrossTrim" option working in ersky9x. The biggest problem is in ensuring the control bit in the EEPROM is not already set from some previous use. We don't want the trims being crossed just because you have loaded new firmware.

Mike.

[Rob Thomson]

Guess it will probably be added to the avr128 version?

Real issue is as always trying to make everything fit!

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[MikeB]

As is often the case, it needs more code to provide the menu option than it does to implement the actual function.

Mike.

[Rob Thomson]

Too true!

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[MikeB]

I'm looking at this as a per model function.

To those who actually want to use cross trims, is this a 'RADIO' function or a 'MODEL' function?

Mike.

[Flaps 30]

For me it is a radio function.

[Kilrah]

Model for me. I tend to use it for the multicopters, but not for my planes. Or I set cross trims only for the first flight, then go back to normal once things are right.

[jhsa]

I think per model would be easy to get confused.. Kilrah if you tend to use it only for the first flight and then back to normal, then it doesn't really matter if it is per model or a radio feature.. I would say, for the complete radio, but I can see that other people might want per model.. flexibility is the moto of these firmwares, right??....

It will be just one thing more to add to the "don't forget to set" check list when you set a new model, or you could be up to surprises in the air..

So, more flexible, or less confusing and safer??

João

[Rob Thomson]

While I see benefits to both methods, i think that the open9x method actually goes beyond this.

Technically, you could use the throttle trim for your rudder. Up to you!

The point being. A simple check box to enable it is great. But not as flexible.

Rob

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[Flaps 30]

Hmm... Per model or radio setup.. Yes I voted for Radio setup now if I tried to revert back to the so called normal trim arrangement. I would find it difficult to remember that I had done so.

Working on the idea of cross trim on a per model basis, would also mean that with each model we should be able to change the stick mode on a per model basis..

[Rob Thomson]

Yes.. But then we would need a magic thingmagig to auto magically move the ratchet to the other stick

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[jhsa]

It depends. If you are into cars or boats you might want a spring on your throttle as well..

[G550Ted]

s-mack is probably working on a magic thingmagig as we speak.

My belief is that cross trim should be a radio option.

Ted

[gohsthb]

I do like the open9x idea of assignable trims. Then you can use the rudder trim to trim the elevator if you want. It would prevent you from having to reach over the throttle stick to reach the trim buttons.
-Gohst

[Kilrah]

Kilrah if you tend to use it only for the first flight and then back to normal, then it doesn't really matter if it is per model or a radio feature..

No, because as I said with multicopters where I need to trim often and very precisely I keep the cross trims.

[kaos]

Don't we have an instant trim already? May be I am missing something here. fly with A/E use left hand to instant trim with RUD/ELE. fly with R instant trim with TRN/AIL.??

[MikeB]

kaos: Cross trims is where you use the trim by the throttle to trim the elevator, and the trim under the rudder to trim the aileron etc. Some people find this useful as they can trim the aileron using the'other' hand than taht holding the aileron stick etc.

On balance, I think it is 'safer' to go for the 'RADIO' option (not the model). It seems to me to have some models with cross trims and some without could lead to confusion.
So I will add a RADIO option to select crosstrims (er9x and ersky9x). There are at least 2 ways of using mixes to create cross trims if you want to do per model cross trims.

Mike.

[kaos]

I understand what you are saying using the trim tab on the other to trim. what I am saying is why not use instant trim with a switch on the other hand. Won't that be easier? instead of using the trim tab, click click click, all you have to do is control the A/E to keep plane straight/level then flip the switch on the other hand once instead of click, click, click? once the A/E is trimmed, do the same for R, use a switch on the right hand to trim the R.
I am not arguing. I am just trying to figure out what this is used for when instant trim can do it easier, use the other hand with just one click/switch. or may be I misunderstood the instant trim how it works?

[Kilrah]

or may be I misunderstood the instant trim how it works?

Yep. Instant trim has only one switch and trims all channels in one go, you can't do one hand then the other.

[G550Ted]

kaos: Cross trims is where you use the trim by the throttle to trim the elevator, and the trim under the rudder to trim the aileron etc. Some people find this useful as they can trim the aileron using the'other' hand than taht holding the aileron stick etc.

On balance, I think it is 'safer' to go for the 'RADIO' option (not the model). It seems to me to have some models with cross trims and some without could lead to confusion.
So I will add a RADIO option to select crosstrims (er9x and ersky9x). There are at least 2 ways of using mixes to create cross trims if you want to do per model cross trims.

Mike.

Looking forward to your future rev to include cross trim option.

Thanx!

Ted

[iflyj3]

FWIW,
I tried the solution suggested:

CH01: +100% AIL NOTRIM
+25% GV1 - where GVAR1 is set to Rtm

This does work. However, one problem with it is the T-Trim on page 2 of SETUP does not go to the new TTM function (Now it is the old ETM switch).

I vote for cross trims to be a radio function.

You fellows are doing a real nice job of creating and supporting the firmware.

Dan Thompson

[MikeB]

T-Trim is one of many built in things that can be done other ways, just uses up mixes etc. If you want T-Trim using the above try this:

CH03: -100% ELE Curve(c1) - c1 = 0,0,0,0,0 - This get the elevator trim (reversed)
CH03: * +50% THR offset(-100) - This scales and reverses the trim on the line above so that it does nothing at full throttle, and is full range at low throttle.
CH03: +87% THR noTrim Offset(15) - Add in the actual throttle, scaled down a bit and shifted up a bit.

Your throttle will now act as thought you have T-Trim, but using the elevator trim.

Just about to test crosstrims, I think T-Trim will work correctly on that.

Mike.

[iflyj3]

Thanks Mike,

Since you are close with cross trims, I will wait.