450 swash leveling question ???

[yardner]

working on my trex pro 450 v2 and trying to get my swash to level at midstick 50%
well i get it to level at midstick but not at low stick 0% or at high stick 100%
90* all servos on the bench before installing

dx6i in DIR mode
throt curve 0-50-50-50-100
pitch curve 0-50-50-50-100

1st pic is at mid stick 50% all is level all three points


2nd pic low stick 0% as you can see the pitch servo is dropping just a little lower??? whats up with that?


3rd pic high stick 100% and here you can see its way off... ail and ele arms are running a little low.?


so what you think guys? what am i doing wrong?
it will fly like this but its not right in the air.
when making turns it want to pitch down and over any which way you rotate/turn it.

thanks
yardner - texas

 

[DAL2855]

What radio are you using? You use the endpoints to ensure swashplate is level at top and bottom end of pitch travel. Or EPA's as they are sometimes referred to as.

 

[Derek]

I'm pretty sure that when you are setting up your swash plate that the Pitch Curve should be linear (0,25,50,75,100). You can always change it back to the way that you want it after you are done.

 

[yardner]

What radio are you using? You use the endpoints to ensure swashplate is level at top and bottom end of pitch travel. Or EPA's as they are sometimes referred to as.

spectrum dx6i

endpoints? mean travel adj. they are all set at 100%
was also looking at swash mix. but i dont think this is something you need to change to correct this problem.

yardner

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I'm pretty sure that when you are setting up your swash plate that the Pitch Curve should be linear (0,25,50,75,100). You can always change it back to the way that you want it after you are done.

dont make any difference same results with linear curve.
was just useing the 50-50-50 to make sure it was at mid stick. 50% when i was checking the swash.

yardner

 

[DAL2855]

You need to have a linear pitch curve, then yes it's travel adjustment that you'll need to adjust to ensure the swashplate is level through out all the travel. Looks to me like you'll only need to adjust the elevator to level the swashplate at full pitch, then at the bottom, bring up the aileron and pitch servos until it's level at bottom of pitch travel.

 

[yardner]

ok dal, i'll give it a try.
but i was under the impression that this is a mechanical problem and not something that's fixed in the radio.

thanks,
yardner - texas

 

[DAL2855]

No, this is not a mechanical problem, what you are doing here by doing what I explained, is limiting the travel of each servo individually so that the swash maintains level throughout full range of pitch travel! Hope this helps!

 

[yardner]

No, this is not a mechanical problem, what you are doing here by doing what I explained, is limiting the travel of each servo individually so that the swash maintains level throughout full range of pitch travel! Hope this helps!

yes thanks, i adjusted the travel so its all level now. high/low
got to put the blade grips back on and give it a test..

thanks

 

[DAL2855]

Awesome! And don't forget once you get everything level and get the head on, make sure to track the blade grips, best thing I've found to do this, is put a flybar into a feathering shaft and slide it down through the bolt hole of the blade grip. Then using the main shaft as a reference point, ensure both of the blade grips are at zero degrees at midstick position! This makes actual blade tracking much easier and faster!

 

[yardner]

yeah, doing it now. using a digital cal. but your way seems alot faster.
doing the HOW-TO Setup helicopter FBL head - Align 3GX / Spektrum - by Marius S, to see if can get an even pitch +/- both ways

 

[Westy]

Usually up may have a small amount of difference at low or high stick.... but if you have at mid stick definitely got all 3 servos at 90º and levelled mechanically .... then you should not have to do much at all with the travel limits on your Tx. In saying that, the cheaper the servos ... the more self centring differences you get (servos ability to go back to perfect centre again)

so to summarise...

at mid stick ..... you do all mechanical adjustments to get 100% level and then check and adjust your travel limits at high and low stick......

Then put your head on ... and mark one blade as the master.....

then ..... check your pitch range and adjust in your swash level..... then..... check you have pos = to neg travel (and equally adjust up or down all 2 servo to swash links to get them the same)

Then ... measure you links on the master blade you marked and match on the slave blade.

Then ..... do a tracking test and ONLY ADJUST THE SLAVE BLADE!

 

[yardner]

sounds good Wes just what i'm TRYING to do.

thanks for the help

yardner-texas

 

[Westy]

good work! you will sort it!

 

[Dirk]

Hi Yardner,

Sorry I've joined this post a bit late. I did notice something interesting. Not sure if it will have any effect on your problem, but I did notice that you seem to have your aileron and pitch servos swopped around in the servo mounts. ( According to your little markers stuck on to the servos )

 

[DAL2855]

Dirk, it really doesn't matter which servo is plugged into which channel, just have to remember it when you're making adjustments and then when you setup nor/rev to ensure the swash is traveling in the correct direction of stick inputs.

 

[Westy]

It does matter guys .... and is good practice to get into ..... PITCH = FRONT LEFT... AILERON = FRONT RIGHT.... ELEVATOR = REAR CENTRE...........

This is also PARAMOUNT of importance if you are using Flybarless setups as you will most certainty become unstuck.

The reason it is so important is so you are not chasing your tail trying to alter mixing and things..... and also getting your CCPM levelling setup ..... you will just become confused and the rubbish bin will be the next location of the heli!

 

[DAL2855]

Yeah that is true Westy! But it can be done no matter which servo is plugged into which channel. But yeah it's definitely a good practice to develop of plugging them into the same channel every time so you don't forget!

 

[Dirk]

Thanks Westy. I also thought it mattered. As does getting the servo arms at 90 degrees with the minimum amount of subtrim. I noticed when you use too much subtrim, you tend to run out of servo travel at max throws and the swashplate starts doing some weird things.

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Yardner, how much subtrim did you use to get your servo arms at 90 degrees @ midstick?

 

[Westy]

Of course it can be done ...... but if you want to confuse yourself and then go and ask for help .... well let me just say I would not be very interested in assisting someone that is just not interested in following the systematic accepted assembly code of practice. As I said .... it is very important to do this on FBL systems or you are asking for trouble as the phasing calculations and algorithms are set up on the STandard international servo configuration method.

It is same with electrical wiring code of practices ..... of course you can wire a house using whatever colour coding you wish (it will work if you have done it correctly)..... however .... you or someone else will get injured diagnosing someones AD hoc wiring coding system.

 

[Dirk]

Apologies Westy, I just noticed that you mentioned about what I've just asked.