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Challenge for HarryC (MPX 3030 question)

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Old 07-20-2003, 03:09 PM
  #1  
shoe-RCU
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Default Challenge for HarryC (MPX 3030 question)

I've had my MPX 3030 tx for a few months now and am really loving the flexibility it provides. I've found something that I would like to do with it and would like some comments and/or ideas.

I fly "full house" open class sailplanes and utilize the "butterfly" mix on 4 wing servos. When landing I move the spoiler control down the flaps come down, the ailerons move up and the elev trims itself accordingly. All very good.

The problem I'm running into is at a different point on the curve say 30% of spoiler for example, the elev trim rate needs to be different that it does at 100%. ie as it is now I can either set it up so as I deploy the flaps the elev trim compensation is fine through the first 70% then at 100% is too much, or is not enough through the first 70% of the deployment then at 100% is just right.


What would be the best way to accomplish different elev trims values for different points along the spoiler's travel? I have thought about trying to use the Gx (that would give me one mid-point which would be adequate) but I'm not sure how to implement that. I've also thought about setting up a couple of USR-MIXs with one of the input being the Heli Pitch control as it has multi point curves built in.

Has anyone done this? Am I crazy or is this feasible?
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Old 07-20-2003, 09:11 PM
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HarryC
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Default Challenge for HarryC (MPX 3030 question)

This sort of situation is one of its few limitations, since multi point curves are the answer. I did once wonder about using one of the heli functions that has a multi point curve but when I thought it through there was some reason I found that it was going to cause as many problems as it solved.

You have correctly identified Gx as a possible solution though it is imperfect as the elevator trim will jump from one mix curve to the other at the Gx point. Assign spoiler as two separate inputs to the mixer and assign elevator to the output. Assign Gx to spoiler, set the trigger point. In the mixer the elevator is connected to both spoiler inputs, set the switch on one connection to Gx * and the other to Gx no *. Then as the spoiler control is moved across the Gx point the * input will go off and the off input will go *. Set the relevant mix values for each spoiler input.

There may be other, better solutions than this that someone else can help with. I only fly power and so all the "problems" I solved were for power models, also I traded in my 3030 for a 4000 a year ago so I am having to give programming help purely from what I can remember. Have you downloaded the extensive Mpx 3030 programming guide from rc-soar.com? It might have an alternative solution

Harry
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Old 07-21-2003, 12:24 AM
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Default Challenge for HarryC (MPX 3030 question)

Hi Harry.

Originally posted by HarryC
This sort of situation is one of its few limitations, since multi point curves are the answer. I did once wonder about using one of the heli functions that has a multi point curve but when I thought it through there was some reason I found that it was going to cause as many problems as it solved.
Hmm I was afraid this might be the case. I can't help but think it might be possible also but I know for sure that it is beyond my feable MPX skills.


You have correctly identified Gx as a possible solution though it is imperfect as the elevator trim will jump from one mix curve to the other at the Gx point. Assign spoiler as two separate inputs to the mixer and assign elevator to the output. Assign Gx to spoiler, set the trigger point. In the mixer the elevator is connected to both spoiler inputs, set the switch on one connection to Gx * and the other to Gx no *. Then as the spoiler control is moved across the Gx point the * input will go off and the off input will go *. Set the relevant mix values for each spoiler input.
Your instructions:
1) Assign spoiler as two separate inputs to the mixer
2) assign elevator to the output
3) Assign Gx to spoiler, set the trigger point.
4) set the switch on one connection to Gx *
5) the other to Gx no *
6) Set the relevant mix values for each spoiler input

My result:
1) okay done
2) ??? does this mean assign the elevator servo to usr-mix1?
3) okay done
4) no idea how to do this
5) see #4
6) see #5



There may be other, better solutions than this that someone else can help with. I only fly power and so all the "problems" I solved were for power models, also I traded in my 3030 for a 4000 a year ago so I am having to give programming help purely from what I can remember. Have you downloaded the extensive Mpx 3030 programming guide from rc-soar.com? It might have an alternative solution

Harry
I've re-read the guide from rc-soar.com a dozen times, nothing in there that relates to this (that I can tell). Thanks for your help once again.
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Old 07-21-2003, 01:02 AM
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Okay I had something to eat and took a fresh look at this. I got the Gx thing working (assuming #2 above is yes) and the only problem with it is no elevator trim as you mentioned. There is no way to add Elevator+T to a USR-MIX? Seems kind of odd. Any other ways you can think of getting around this problem. Other than that this seems to be doing what I wanted to do.... thanks again.
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Old 07-21-2003, 07:13 AM
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Oops, my mistake, I forgot that you also need Elevator plus trim as one of the inputs, and yes it is elevator servo connected to the output. Go back and assign Ele+T as an input, and then assign the ele servo to the output again otherwise it will not pick up the fact that you have added Ele control as an input.

I can't remember now what the symbol for Gx in the switch parameter looks like, but if your spoilers are on slider E then the letter E might well come up as the symbol!

Go into the USR MIX and select the ele servo, select spoiler input 1. There are two parameters to adjust, these being the switch and the value. The switch is probably set to ON. Activate that parameter and press +, it will scroll through the switches S1, S2 etc, something like SG, (or Gx or GE or SE) will come up at the end of the list? You toggle the * on or off with the R button. * indicates that a switch is currently ON, so set one spoiler input to be * and one not to be, then when the spoiler control passes the switch point they will swop over.

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Old 07-21-2003, 07:27 PM
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that works, thanks again!
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