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All Forums >> RC Helicopters >> Electric RC Helis >> E-Flite Helicopters >> servo alignment
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servo alignment - 5/18/2008 11:03:13 AM   
Phill86


 

Posts: 128
Joined: 1/6/2008
From: Not Applicable, UNITED KINGDOM
Status: offline 		Hi.
Ive read loads of threads on servo alignment but not 100% sure if you make the servos 90degrees with the servo arm to the case of the servo or if you make it 90 degrees to the push rod that leads to the swash plate with the screew at the centre of the servo.
Thanks for clarifying this for me.
       Post #: 1

RE: servo alignment - 5/18/2008 2:58:08 PM   
DrunkYoda


 

Posts: 283
Joined: 3/22/2007
From: Maineville, OH, USA
Status: offline 		Actually it's the screw as this is the pivot point for the servo. Also 90 degrees to the swashplate if looking at it level. Servo should be straight across horizontally and pushrod should be directly veritical and swash perfectly horizontal and level.


DY

(in reply to Phill86)
       Post #: 2

RE: servo alignment - 5/18/2008 3:01:08 PM   
Phill86


 

Posts: 128
Joined: 1/6/2008
From: Not Applicable, UNITED KINGDOM
Status: offline 		thank you

(in reply to DrunkYoda)
       Post #: 3

RE: servo alignment - 5/18/2008 3:16:59 PM   
DrunkYoda


 

Posts: 283
Joined: 3/22/2007
From: Maineville, OH, USA
Status: offline 		I saw a cool way to level your swash on youtube. You use an allen wrench.

Remove the head above the swash. Twist or cable tie an allen wrench upside down or 90 degree at bottom, to the main shaft. Now twist the wrench around the shaft is the swash the same at all points around the shaft? if no alter until the allen wrench is exactly the same at all spots. MAKE SURE to do this with esc on, motor disco'ed, idle up on and center left sitck, and swashplate should not hit the base if you do full downward motion on stick. You will notice some binding on the collar if you have it too low.

Once the swash is level then you can work on leveling everything else.

DY

(in reply to Phill86)
       Post #: 4

RE: servo alignment - 5/18/2008 3:20:53 PM   
DrunkYoda


 

Posts: 283
Joined: 3/22/2007
From: Maineville, OH, USA
Status: offline 		By the way it's way worth it to do this yourself and not rely on anyone or anything else. You'll learn so much more this way.

DY

(in reply to DrunkYoda)
       Post #: 5

RE: servo alignment - 5/18/2008 11:39:49 PM   
Wolfpackin


 

Posts: 968
Joined: 6/4/2007
From: Avon, CO, USA
Status: offline 		A swashplate leveling tool, or the allen wrench idea, is worth its weight in gold.
The last few times I used one to level my swash at low, half and full stick I didn't need any trim for the heli to fly perfectly.
And I'm still running that way, with zero trim on cyclic.

This is the tool I use:Trueblood Engineering

And the bench users guide within that page is the absolute best, most clear and concise, description of what needs to be done to get a perfect swashplate setup.

I highly recommend reading it even if you don't intend on getting the tool.

(in reply to DrunkYoda)
       Post #: 6

RE: servo alignment - 5/19/2008 6:51:52 AM   
Phill86


 

Posts: 128
Joined: 1/6/2008
From: Not Applicable, UNITED KINGDOM
Status: offline 		Thanks wolfpackin for the links. I have got one of thoses I had it imported to the uk as I could not find any leveling tools at the time.
So far I have leveled servos 90degrees,+ swash. I am waiting for parts to be delivered tomorrow to complete my setup.
It is level throught the range and as it is a stock built heli from eflite I am hoping everything still perfect center of gravity and she will fly perfect.
This is the first major repair that I have done, I have all the recomended tools, so I am hoping I have used them correctly and she flies like an angel.
will post back once ive completed the rebuild.
Thank you for your suggestion and help. Couldnt do it without you guys

(in reply to Wolfpackin)
       Post #: 7

RE: servo alignment - 5/19/2008 1:40:46 PM   
DrunkYoda


 

Posts: 283
Joined: 3/22/2007
From: Maineville, OH, USA
Status: offline 		Yeah I can let her go for 2-3 seconds before I have to do any (at that point major movements).


I do see many people recommend that you remove the springs from both sides of your transmitter(except rudder channel). There really is no centering on a heli, you're always going to be moving both sticks.

Personally I have my springs in still, some people swear by removing the elevator and aileron springs. I have it trimmed well enough that center is pretty centered. I do constantly have to battle the spring to maintain, I've thought many times about removing.


Anyone else have thoughts on that?

DY

(in reply to Phill86)
       Post #: 8

RE: servo alignment - 5/19/2008 2:42:42 PM   
Carljw


 

Posts: 102
Joined: 1/4/2008
From: Moon Township, PA, USA
Status: online 		I am wondering if the Trueblood will work on a CP Pro I just ordered one. I am thinking it might be too loose on the shaft but I will give it a shot since I will be getting a B400 in a month or two anyway. Mabey I can rig something to make it tight on the shaft with a washer or something.
Carl

(in reply to DrunkYoda)
       Post #: 9

RE: servo alignment - 5/19/2008 7:39:18 PM   
evdreamer


 

Posts: 2379
Joined: 8/12/2007
From: Lincoln, NE, USA
Status: online 		I still use all my springs too. I loosened the screws so my hands don't get tired flying. There is just a little resistance. I might be the odd man out, but I like fighting the springs a little. I learned my stick orientations by knowing were I should feel resistance to do a manuever.

Nick

_____________________________

Since I started this hobby money seems to keep disappearing. :)
T-Rex 450SEV2, Gaui 200 SD

(in reply to DrunkYoda)
       Post #: 10

RE: servo alignment - 5/19/2008 10:48:05 PM   
Phill86


 

Posts: 128
Joined: 1/6/2008
From: Not Applicable, UNITED KINGDOM
Status: offline 		I have the bits that I was waiting for and I have put them on. (seesaw holder)
Everything is level.
The problem I now have is sorting out the pitch. I spent all evening trying to do it, but I just can understand it.
At the moment my red blade (tipped for tracking) is +13 full, -0 centre and -5 at no stick.
The blue blade is +13full, 0 at centre and -3 at no stick.
I adjusted the red blade and the reading is +11 full,-2 centre and -7 no stick.
I seem to be turning in the right direction, but just cant get both sides to be anywhere near the same or what they should be. (+10, 0, -10)

The pushrod that I adjust is the same as the tracking so now my tracking is way out.
Please could anyone tell me where I'm going wrong.
Many thanks

(in reply to evdreamer)
       Post #: 11

RE: servo alignment - 5/19/2008 11:42:04 PM   
Wolfpackin


 

Posts: 968
Joined: 6/4/2007
From: Avon, CO, USA
Status: offline 		Are you checking these pitches with the motor unplugged and the heli in idle up mode?
If not you need to do that or change the Throttle Hold curve to 0-25-50-75-100.

Next thing is to make sure at half stick the swashplate, washout base arms, flybar control frame arms, blade grips and mixer arms are all level and parallel with each other. Otherwise you will never get linear movement and consistancy in regard to pitch.

I'll see if I can get SeaComms to jump in on this but let me know if you got that far.

(in reply to Phill86)
       Post #: 12

RE: servo alignment - 5/20/2008 8:57:35 AM   
Phill86


 

Posts: 128
Joined: 1/6/2008
From: Not Applicable, UNITED KINGDOM
Status: offline 		Hello.
I am trying to set it up on a DX7 that has the settings below.

motor is disconected but I was in thottle hold and not idle up. Everything is level apart from the blade grips, but that may be because of the pitch curve. I do not really understand pitch / thottle curve so I just put in the settings Casey Lamm suggested to use with the DX7.
http://www.rcuniverse.com/forum/m_7464466/tm.htm

I will try doing it with my DX6i and see what happens there.
Thank you for your help.


Throttle Curve -EXP OFF
Norm L - 0.0, P1 - INH, P2 - 50%, P3 - INH, H - 100%
ST-1 L - 100%, P1 - 92.5%, P2 - 85%, P3 - 92.5%, H - 100%
ST-2 L - 100%, P1 - 92.5%, P2 - 85%, P3 - 92.5%, H - 100%

Pitch Curve - EXP OFF
Norm L - 35%, P1 - 42.5%, P2 - 50%, P3 - 75.0%, H - 100%
ST-1 L - 0%, P1 - INH, P2 - 50%, P3 - INH, H - 100%
ST-2 L - 0%, P1 - INH, P2 - 50%, P3 - INH, H - 100%
Hold L - 35%, P1 - 42.5%, P2 - 50%, P3 - 75.0%, H - 100%

(in reply to Wolfpackin)
       Post #: 13

RE: servo alignment - 5/20/2008 6:28:10 PM   
DrunkYoda


 

Posts: 283
Joined: 3/22/2007
From: Maineville, OH, USA
Status: offline 		Throttle curve is just the amount of power you have at different points.


0 being no throttle, 2 being up some on left stick. 3 being midstick. Just a one to one. This is for regular. For idle up throttle is always on there is no low point. Mid (so 3) should be about 75-80 percent power then each end point should be full power so it's a big V.


Pitch on the other hand is just the blades. It should pretty much always be the same but using idle up gives you the most correct settings.

The idea is at point 3 (mid left stick) the blades should be level and 75-90 percent power or not doing anything but spinning the blades. then at low point the blade pitch should be at full neg pitch whatever you have that set for but usu between 10-12. At point 5(high left stick) you should have most positive stick or 10-12 meaning with throttle curve you have full power and full pitch.

On normal the pitch is 0-100 is in various configs some people like 45(being just negative).65(neutral)..(half positive)75.(mostly positive)88.(full positive)100 or some combo of such.

Meaning at low stick and normal throttle the power is off and no pitch or some negative pitch for those who want it more correct., at mid stick you have mid power and medium pitch and at high stick you have full power and full pos pitch.

That's all that means

so

throttle on idle up is big V
Pitch is a straight line 50 being "neutral" 0 being full neg and 100 being full pos.

Throttle on Reg mode should be a straight line from 0-100 or some combination
Pitch should be starting at 45 or so and going to 100 in a curved pattern

Correct me if I'm wrong guys just doing it from memory.

DY

(in reply to Phill86)
       Post #: 14

RE: servo alignment - 5/20/2008 10:38:26 PM   
Wolfpackin


 

Posts: 968
Joined: 6/4/2007
From: Avon, CO, USA
Status: offline 		Phill,

Those curves look fine.

My main point was if you are measuring pitch with throttle hold on then you will be getting the pitch for that curve.
In otherwords Throttle Hold has it's own pitch curve.

So, in the examples you posted above if you are switched to Idle up with Throttle Hold on you should actually get -3/0/+10 for
pitch at low, half and full stick instead of -10/0/+10.

Does that make sense?

(in reply to DrunkYoda)
       Post #: 15

RE: servo alignment -