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Old Jan 28, 2013, 06:35 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
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I used to have some 85 and 81's here a long time ago (They are an old servo). From memory they seemed to work just fine. They are analogue remember, so they wont have the accuracy or holding power of a digital servo. I honestly think you should just go with a JR285 or a hs 5065 and call it a day.

No need at all to run a hs 85 on the elevator, even if you're shootin for 300mph.

Ball links are the best linkages for these things. They last way longer then a typical clevis and are easier to maintain. Especially if you buy the right ones. Us heli guys know just how robust ball linkages are
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Old Jan 28, 2013, 08:42 AM
Why the dirt on the wings?
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New York
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Quote:
Originally Posted by blitzu View Post
..one other question-u know how the hitec 85mg hunts arnd abit with centering...does the 85bb have the same quirks?
Yes they do, except with the BB, you do not have the metal geartrain, so there is less slop. Otherwise, it is identical to the mg version



Hey SB, whats the new avatar ? I can make out teeth .................
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Old Jan 28, 2013, 10:50 PM
I am actually really slow
SlowBarless's Avatar
Brisbane
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Originally Posted by moparmyway View Post
Hey SB, whats the new avatar ? I can make out teeth .................
Front of a P-40 Warkhawk! Its about 50 years before my time, but I still think it's one sexy bird
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Old Jan 29, 2013, 01:48 AM
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Yip-ball links for sure
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Old Jan 29, 2013, 03:09 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
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Not sure if Ive posted this before Blitzu, but these are the links/balls to get.

http://www.quickuk.eu/cat/general_pa...s___links.html
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Old Jan 29, 2013, 09:17 AM
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Mreyello's Avatar
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About ball-linkage:

Quote:
Ball links are the best linkages for these things. They last way longer then a typical clevis and are easier to maintain. Especially if you buy the right ones. Us heli guys know just how robust ball linkages are
I would agree to most of that but its not the ball-joint itsself i am worried about.

Let me take this example:
http://www.rcgroups.com/forums/showp...&postcount=291

If you bolt the ball right to the side of the horn you dont have a straight force direction,you have a kind of 90°lever of 5mm at your horn,which wants to trist your horn.
As usual ailleron-horn of fiberglas or even carbon are about 1-1,5mm thick they can take massive forces in axial direction but are pretty weak if you twist them.
The longer your horns are the worse!!!

I dont want to think about the situation at the inside with plastic servoarms!!!

Such a linkage will appear slope-free but it will be more flexible at high ailleron -forces than a simple( but well done) clevis or z-rod connection.

It would be bossible to use two horns with the ball bolted in between, maybe this can give some inspiration:
http://www.cnc-extra.de/epages/17245...Products/LDSQU


Regards
Yello
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Old Jan 29, 2013, 09:40 AM
I am actually really slow
SlowBarless's Avatar
Brisbane
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You are absolutely right Yello, but the same forces are applied with Z or L bends to.

I did say in my post you gotta get the right stuff. See photo as to how I did mine.

At first I was concerned about the plastic control horn on the servo twisting. But It doesnt seem to be a problem. The arm is so short there's no way its going to flex. The servo will stall before something flexes!

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Old Jan 29, 2013, 10:08 AM
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With clevis or z-connector there is no torsion forces at the arm, when linkage is proper aligned.
The z-rod gets some bending forves at the corner wich is easy to handle by a 1.5mm rod due to the short lever.


Your solution looks nice, you solved the problem at the outside and i am sure it will work reliable but for me its still not
Quote:
best linkages for these things


I dont want to keep anybody away from using ball-links,just wanted to show the problems.

Yello
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Old Jan 29, 2013, 10:21 AM
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By the way,
I do not use z.rods cause they may be able to move, i use a simple steelrod bent 90° and lock it with a small tube:

http://static.rcgroups.net/forums/at...igor%20006.jpg
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Old Jan 29, 2013, 10:24 AM
2012 NZ Speedcup - 231 MPH
DownUnderPilot's Avatar
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Joined Mar 2006
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For me, the ultimate is Gold n Rod and sullivan clevises for long reaches, and just threaded rod with the same clevis at each end when short distances are involved.
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Old Jan 29, 2013, 10:40 AM
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Darron's Avatar
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Ben
Where you have the ball link on the aileron the pivot point is such that it will create differential and also the downward moving aileron will move quicker then the upward.

You probably wouldn't notice this if you're not trying to fly a course otherwise you end up spending a lot of time trying to get the diff right.

Also the forces on the ball at the servo end will twist the servo arm and with the harder servo arm material will break it. I've even broken servo arms with z-bends using the thinner fitted servo arm supplied with the amd servos. I always replace with the disc version which I cut to suit as it is thicker.

Just saying.....
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Old Jan 29, 2013, 12:23 PM
I am actually really slow
SlowBarless's Avatar
Brisbane
Joined Jun 2008
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I thought I did a good job with these linkages

I think at the end of the day I just got sick of messing with Z bends and clevises (used to building helis, clevises are strange to me ). I wanted something that could be easily maintained and something that wouldn't develop slop quickly.

Don't know how you managed to break a servo arm Darron. I'm using the fattest servo arms that came with the servo and reshaped them so it wouldn't bind on anything. I don't think I have to worry about breaking servo arms.

Regards to the differential problem. I haven't flown this model as Its a friends one so can't comment on how well it rolls. However it looks to be sweet in the corners. I thought because the aileron tucks underneath the bottom skin, reducing its surface area, slightly more down is needed to get the plane to roll on axis? Although I have been told that for proper racing more up then down helps?
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Old Jan 29, 2013, 01:20 PM
Livin it UP when Im goin DOWN
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Is the differential issue caused by the link not being directly over the hinge line, or some other features?
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Old Jan 29, 2013, 02:04 PM
2012 NZ Speedcup - 231 MPH
DownUnderPilot's Avatar
New Zealand, Tasman, Richmond
Joined Mar 2006
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Quote:
Originally Posted by Arcteryxxx View Post
Is the differential issue caused by the link not being directly over the hinge line, or some other features?
Correct. The link should ideally be directly over the hinge line. Of course sometimes that is not practical.
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Old Jan 29, 2013, 02:09 PM
2012 NZ Speedcup - 231 MPH
DownUnderPilot's Avatar
New Zealand, Tasman, Richmond
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Quote:
Originally Posted by Mreyello View Post
As usual ailleron-horn of fiberglas or even carbon are about 1-1,5mm thick they can take massive forces in axial direction but are pretty weak if you twist them.
The longer your horns are the worse!!!
You should try these Yello, they are untwistable, literally. Really an amazing product for $2!

http://www.hobbyking.com/hobbyking/s...2pcs_bag_.html
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