Lnewqban

Besides a Z-bend, which I don't want to use, what are the proper ways to connect a servo wheel-horn to a pushrod linkage?

http://www3.towerhobbies.com/cgi-bin...?&P=9&I=LXH364

Advices are welcome

FallDownGoBoom

My Feedback: (1)

For critical linkages (elevator, rudder, ailerons) I like either push rod keepers (see picture 1), or using another clevis. If you use a threaded clevis, then you need to use a jam nut to make sure the push rod does not rotate from vibration.

You can also use EZ link connectors (picture 2). I use these for things like throttle linkages and flaps. If one comes loose, the airplane will still fly. Some people will use them on all linkages, but they make sure they inspect them regularly so they won't come off in flight.

SeamusG

Are you familiar with Airfield Models website? If not, definitely worth the read. www.airfieldmodels.com/index.html

My approach is constantly changing. With that said here's an approach that I follow.
Parts:

[*]wire (2-56 or 4-40) threaded on one end[*]solder-on connector that is threaded on 1 end and open on the other - it fits over the wire and soldered to the wire while providing a threaded connector for other components[*]dubro swivel ball link that is threaded onto the connector and has a 2-56 allen bolt the attaches the link to the servo wheel[/list]pic 1 - dubro 2-56 swivel link
pic 2/4 - example of installation of swivel link on threaded end of a wire. You can cut the thru-bolt flush with the bottom of the backside nut. Make sure that you loctite the nut
pic 5 - samples of solder-on components - threaded connectors and clevis.

HTH

Lnewqban

Thanks FallDownGoBoom,

The first one shown I cannot use because it gets jammed against the wheel.

FallDownGoBoom

My Feedback: (1)

Can you change the wheel to a "horn" type of servo arm? That would eliminate your jamming problem.

Lnewqban

Yes, I could.

However, I want to achieve aileron differential with it, making the holes at certain angle.

This is for a central aileron servo for a high wing scale model, for which I don't want to use independent aileron servos.

Do you believe that ball links will work?

Thank you for your responses.

FallDownGoBoom

My Feedback: (1)

Ball links would work... and I like them better than the EZ connectors because they use a nut to hold them on, and you can use loctite to decrease the chance of failure. Another choice would be to use one of those 6 armed servo horns, and cut off the arms you don't need.

Lnewqban

Excellent; just what I needed.

Again, thank you both very much, SeamusG and FallDownGoBoom.

Dubro 2-56 swivel links will be!!

SeamusG

The swivel links provide a very positive connection - no slop what so ever. They are fairly easy to remove by popping the servo arm off, securing the nut and removing the allen bolt. Movement to a new hole will require drilling out the new hole. Standard arm holes are 1/16" and the 2-56 hole requires something bigger (short memory syndrome prohibits me from instant recall on such details ). Just know this before going to the field so when you start "mechanically" trimming your ailerons you have the right tools.

SeamusG

BTW - according to my LHS (just got off the horn with him) Dubro has 2 different sizes of solder-on threaded ends and Sullivan has 2 additional sizes. Size? The thread size (2-56 or 4-40) and the ID of the solder-on end. Sullivan includes a small ID w/ 2-56 with their cable control rod kit. The ID of these is too small to fit over the 2-56 rod. You will need to locate / test-fit either the Dubro or larger Sullivan pieces.

HTH,

Lnewqban

Great helpful info, thanks.

MinnFlyer

My Feedback: (4)

For Differential with a star wheel you can do this

Lnewqban

Thanks, Mike.

The only problem is that I don't know how to make a decent Z-bend.

SeamusG

lnewqban - is there such a thing as a "good z-bend"?

MinnFlyer

My Feedback: (4)

You can use an L bend with a keeper or a clevis or ball link

SeamusG

MikeB - Is there any advantage to have both ends of a control rod "adjustable"? I'm discarding the idea of having a rod with left-hand threads on one end and right-hand threads on the other end. I like the idea of using an "L" bend with a keeper. Only down side I can think of is the use of a nylon keeper.

Thanks for your input!

MinnFlyer

My Feedback: (4)

No advantage really

SeamusG

Is this what you are refering to as a keeper? It's a Dubro E/Z Link [img]file:///C:/Users/Seamus/AppData/Local/Temp/moz-screenshot.png[/img] pic hijacked from Tower ...

MinnFlyer

My Feedback: (4)

yes