Uneven Collective

[LoveToFly1]

Originally Posted by gtrsteele

Referencing the main shaft requires removing the swash and the head to get enough realestate to calibrate the RC logger. What a pain in the ass. I may start using mast that you can screw into the RC logger.



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no, you dont need to do all of this. all you do is follow my previous post. take the blades off, and insert a carbon rod the same diameter of you blade grip bolt through the bolt hole, and line the carbon rod up with the center of the mainshaft. take a few steps back and look at the heli from the side, it is fairly easy to line it up perfectly. then, install you blades with the fbl still on the trim page of your software (so the blade grips are locked still), and use your blades to set 0 pitch at that point.

[gtrsteele]

No carbon rods laying around, but shouldn't the mast that screws int the rclogger accomplish the same thing?


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[popokatepetl]

Here are my two cents.

The only reason for not having the equal collective is the geometry from the cyclic servo horns up to the blade grips. Just a little off from being square and here you go. Two things to do.

1) get the geometry right - easy to say but harder to do. This is actually the best you can do.

2) lower the collective end points in the radio to get the equal collective. Never go above 100% in the diagnose for any chanel!!! You can go only down with the end points. This is MANDATORY!!! Just get your geometry as best as possible and then fine tune it like this. That's what I do.

I would say bellow 1° difference you can fine tune it by #2. Everything more than 1° difference and you should play with your helicopter's geometry.

[abanihani]

Originally Posted by popokatepetl

Here are my two cents.

The only reason for not having the equal collective is the geometry from the cyclic servo horns up to the blade grips. Just a little off from being square and here you go. Two things to do.

1) get the geometry right - easy to say but harder to do. This is actually the best you can do.

2) lower the collective end points in the radio to get the equal collective. Never go above 100% in the diagnose for any chanel!!! You can go only down with the end points. This is MANDATORY!!! Just get your geometry as best as possible and then fine tune it like this. That's what I do.

I would say bellow 1° difference you can fine tune it by #2. Everything more than 1° difference and you should play with your helicopter's geometry.

For this issue i have been adjusting the pitch curve in the Tx to get both positive and negative equal, is that wrong? i have not experienced anything bad doing it this way but need to know if i am wrong using this method.

[popokatepetl]

Originally Posted by abanihani

For this issue i have been adjusting the pitch curve in the Tx to get both positive and negative equal, is that wrong? i have not experienced anything bad doing it this way but need to know if i am wrong using this method.

That's actually exactly the same. Just don't raise but lower only.
End points are general thing and collective curve can be different for different flight modes. That's all...

[abanihani]

Speaking of that, for optimal geometry, is the 90 degrees role is for the servo horn hole or for the swash plate rod. Often times the heli is build in a way that the rod is not truly parallel to the main rotor shaft, offset in an angle so to speak. So is it better then to attach the rod to the swash plate first and then get the 90 degrees to that rod instead striving to get 90 degrees between the servo and horn?

[popokatepetl]

Correct procedure

First of all you should have long enough servo horn. I personaly set 10° cylic and try to have servo travel between 70-100 points.
Now I go to the TRIM page and set the servo horns square to the links which goes to the swashplate. I mean servo horn to the link and not the servo horn to the servo's case like I see quite often!

Now I measure the positive and negative collective. I move the whole swashplate up or down by changing values in TRIM page for all three servos at once. Do it until you have equal collective positive/negative.


That's the right procedure. I do it only on my 700 which I want to have in 100% shape. On my 500 class helicopters I just set it close enough let's say <0.5° and then use the radio's end points for collective to fine tune it.

[Smith T]

Originally Posted by popokatepetl

Correct procedure

First of all you should have long enough servo horn. I personaly set 10° cylic and try to have servo travel between 70-100 points.
Now I go to the TRIM page and set the servo horns square to the links which goes to the swashplate. I mean servo horn to the link and not the servo horn to the servo's case like I see quite often!

Now I measure the positive and negative collective. I move the whole swashplate up or down by changing values in TRIM page for all three servos at once. Do it until you have equal collective positive/negative.


That's the right procedure. I do it only on my 700 which I want to have in 100% shape. On my 500 class helicopters I just set it close enough let's say <0.5° and then use the radio's end points for collective to fine tune it.

Popo that makes sense and I have been doing it wrong all along this would explain why occasionally I have to adjust the link to level the swash instead of having them all the same exact length. I had to adjust two which were 1 mm and .5 mm off to level the swash after my last crash. Drove me crazy but adjusting the linkage was a habit I picked up from starting with micros.
Only problem now is I have to go set up my helis again. Thanks for the info.

[kayakboy69]

OR you can throw the POS Align digital gauge against the wall and buy rc logger ... like I did! ..

Every time I went from zero at mid stick back to zero my max pitch changed by 3 degrees!

All good now ...

[kayakboy69]

Thanks guys I will go back and double check all linkage .. its on my E5