DX7 + Trex450s
05-21-2009, 02:00 PM
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DX7 + Trex450s
Please help I am in the process of setting up my new DX7 with a trex 450 s. I am used to a raptor 50 with Futaba 9c super so going back to the drawing board with this machine and hand set . When I got the set up it appeared to decend too quickly in normal mode, so in an attempt to settle that down I adjusted the low end pitch settings. As the transmitter is new to me I have mistakenly changed something!!On throttle up the heli seems to add negative pitch! insteadof positive (motor powers up - heli swash platemoves down and heli does not lift) I have tried to reverse the servos but this does not work. I obviously need to get my head around eccpm but could do with getting this frustrating problem ironed out
05-21-2009, 02:35 PM
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RE: DX7 + Trex450s
I have the same setup as yours, DX7 and Align Trex 450SE V2.
How did you proceed into setting up the low end pitch setting?
On the REVERSING SW menu, I have the two servos AILE and RUDD reversed.
On the SWASH MIX menu, I have the AILE which is reversed.
-60% AILE
+60% ELEV
+80% PIT
I assume your curves are properly setup, and not inverted by mistake.
I Kept all values at 0% in the REVO MIX menu, all TRAVEL ADJUST at 100%, all SUB TRIM at 0, and of course selected 3 SERVOS 120° in the SWASH TYPE menu. That's basically what I have setup for my model.
05-21-2009, 03:16 PM
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RE: DX7 + Trex450s
Thanks for your reply fadi81 - but still got a swash plate which moves down when I move the collective up. I am happy to admit this type of electric heli and mixing is new to me (I knew my previous machine and transmitter inside out) but I must be doing something real simple wrong here.
05-21-2009, 03:29 PM
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RE: DX7 + Trex450s
Can you elaborate how I should go about changing the low end pitch. As soon as I got the machine I did a quick hover indoors, all seemed ok but th machine decended too quick on throttle down in normal mode. At this stage, and keen to try out my new machine I never knew what neagtive pitch I had (did not measure this), but could see the pitch curve point 1 was at zero. I then proceeded to adjust point 1 just so it was not as sensitive at this position. I've obviously screwed things up with an over zealous approach. Please help. I have now got a swash plate which still goes down when I raise the collective and a swash plate that has it's fore and aft back to front, yet reversing the servos just makes things worse. Definately pilot error but stil worth a itte help please>
05-21-2009, 03:36 PM
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RE: DX7 + Trex450s
To reverse the pitch function reverse the swash mixing value.
If your pitch is moving the wrong way at +50 set it to -50
If you dont have enough pitch, increase the value away from 0 till you get the total throw you want. So if at +50 you're only getting 7 degrees of throw, increase it to +60 and check the pitch throw, tweak as needed.
05-21-2009, 04:25 PM
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RE: DX7 + Trex450s
Thanks barracudaHockey. That did the trick. Going to spend some time getting up to speed on both the machine and transmitter. Thanks for you time
05-21-2009, 04:25 PM
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RE: DX7 + Trex450s
sydr1234, my low point on my throttle curve is at approximately 30% not zero, because with my specific setup, servos, links and so on i get a negative pitch if i go below 30% on the pitch curve, and I don't want that on the hover stunt mode.
My hover stunt mode goes from 0deg pitch to 10deg pitch, on the curve I've setup three points only, 30%, 82% and 100%.
However, on my 3D flight mode, stunt 2 for instance, I have the pitch curve at 0% on the lower point so that i get a negative 10deg pitch at that end.
If you see that you can place the point on your curve up to 100% and still not get positive pitch, then go to the SWASH MIX menu, and increase the value from for example the default +60% to +80%.
+80% is exactly the value that I've dialed on my model for the PITCH.
but if you really reach +100% on the pitch curve and still get a negative pitch on the blades, I'd say you have terribly setup mechanical links that need to be reconsidered.
For information, the DX7 by default sets the SWASH MIX value at +60% for all of the AILE, ELEV, and PIT.
Usually one of these should be inverted i.e. -60%, in my particular case I had to invert the AILE one.
The value is something else, 60, 80, 100 or whatever, you decide depending on what sensitivity and travel you prefer for your swash plate.
The sign, positive (+) or negative (-) is for inverting the control.
I assume that your cyclic controls are working fine, ELEV and AILE, so try to put a negative sign for your PIT to invert its travel.
if you have +60% on the PIT in the SWASH MIX menu, then change it to -60%. if you have the correct direction of travel now, then experiment with the value -60 or -80 or -40 in order to get the travel that you want.
