I am presently installing the pushrods in my Venture 60, which will have a Saito 72 (four stroke) pulling it, and I would like a few opinions as to which pushrod connectors would be best to use on the servo end. I have used the GP Screw-lock connectors (where the wire from the pushrod slips thru the brass block and a screw is tightened to hold it in place) and I have used the GP threaded Ball links. I have had no problems so far with either, so far.
The Screw-lock connectors are by far the easiest to adjust, but I wonder if they aren't likely to loosen in flight. Also, should I grind a flat spot on the wire where the screw tightens down on it or is that just overkill? I have been told that a four stroke vibrates more than a two stroke, so will this be a factor?
The Threaded Ball links seem to be the strongest and surest, but are the worth they extra trouble when they have to be adjusted?
Just wondering which you guys prefer, and why.

Thanks.

Those are OK for little foamys and throttle serovs. I wouldn't even think of them with your plane. They just don't have the strength to hold up to that setup.

The Robart ends are the best, followed by the Sulivan ends with the clips and then the Dubro ends. All screw ons and I would suggest the #4 sized ones. It depends on which pushrods you are using as to how to attach the screw ends to it. With the likes of the golden rod, you screw in a short length of threaded rod in each end. Make sure you use lock nuts to keep things tight. If you are using wood pushrods, you would use the short lengths of rod threaded on one end and bend a L in the unthreaded end and a hole in the wood and a grove length wise to accomidate the wire. Then lash the wire to the wood end with a strong button thread and then glue it. For very short pushrod lengths, you can use the bare wire, soldering a link on one end and using the screw on links on the other. There are lots of possibilities including carbon fiber push rods. I'm sure one of the guys has a How To link that will follow soon.

Donl

Agree w/ Campgems- never use the screw down pivots for a control surface. I prefer the Sullivan clevises with the little clip. I would think the 2-56 thread size should be fine for a 60 size plane, though. The Sullivan clevises also have a pin that is a better fit in the holes of the control horns. The other brands of metal clevises (Dubro & GP, anyway) have a smaller pin, which introduces slop. I have used the GP brand ball links, but also found them quite sloppy. The best ball links are the ones with captured ball, where the screw actually goes through the ball. I don't like to use ball links on plastic arms, because it moves the point of force away from the arm, and introduces a twisting force on the arm. If you use metal servo arms or metal control horns, they are strong enough to resist that twisting force without distorting.

Everything that FlyingPilgrim and Campgems said.

The only places that I would consider using the screw locks is on throttle and nose wheel connectors. Even then, I'm not a great fan of them because they can slip and do so occassionally.

For that size of plane, I like to use the Sullivan clevises with clips also. I am not convinced of the need for ball links on them.

I'm only using screw locks on the throttle and nose wheel..

All others are soldered clevis on the servo end with a piece of fuel tubing on the clevis to lock it shut.
Horn end is either a screw on clevis with the same fuel tubing lock or a ball link with a double horn (double sheer setup)

This setup does not introduce any twisting loads on the servo arm or control horns.

I use the adjustable screw on connectors and they work fine a little thread lock and they are not loosening up at all,I would recomend using the more permanent metal retainer rather than the rubber one that can be removed, it will loosen up over time for critical areas there handy for multi task servo situations..
if you file a flat in the pushrod like you have stated there a perfectly fine connector for all uses not just for throttle.
when I have a dedicated servo the I will use the Dubro Quick connect the one that slides over the "L" bend and snaps on the pushrod there reliable and simple,a good rule whenever possable keep it simple,the good old Z bend is also a viable and reliable method of connecting pushrods to servos.
here is the inside of my latest P-47 the pull/pull with the rudder pushrod using a EZ connector,my forward servos throttle and retract servos with EZ connectors and the one not hooked up will have a Quick connect for the elevator,as well as for the ailerons and flaps.
what I don't use is soldered on connectors, when done right there fine but a bad solder joint can fail, when I use a snap on type I will use the screw on end nylon connector.
all my warbirds,the 4 I currently have are 4st powered, its about comfort level if you feel the connector your using is solid and can pass a basic field test moving the control surface with out slipping, then there you go, if it looks like it may be fragile with potential to fail then its a no go.

First of all, how did you end up with a Venture 60? I scrounged for months and finally found one last fall. To your question. I have found the Hayes nylon clevis with steel pins are a good for rod ends, http://www3.towerhobbies.com/cgi-bin...&I=LXK847&P=ML . Ever since I had an elevator metal clevis come loose from vibration(and lost the plane) I have used the nylon clevis. The metal rod to metal clevis has just enough tolerance looseness at the threads that vibration over time can wear the clevis threads. Oh, my Venture was just finished in Dec 07 and is now my everyday flier.

The secret to the screwlock (EZ Connectors) connectors is once you have the adjustment correct, loosen the screw, apply a drop of blue locktite and retighten. The screw will not slip doing it that way. I have flown planes as large as an 86" wingspan with an OS 1.60 doing it this way and have NEVER had a failure of the EZ Connector.

Prior to using locktite I had some problems though.

Locktite is a good idea for those connectors.

Personally, I haver been using them for years on up to 60-size planes and never had a failure - BUT... I make sure that they are TIGHT to begin with.

That's one of the reasons to use a jamb nut to snug against the clevis once it is adjusted. The jamb nut will also prevent any radio interference from metal to metal intermitent contact.

Hey Guys, thank you for your opinions; that's exactly what I wanted to hear - several different opinions with reasoning behind them.
Campy and MinnFlyer: That's the way I installed the EZ connectors: Find the right spot, mark it, grind a flat spot about 1/2" both ways from the mark, set it right and use blue locktite, and screw it down tight. I always check the linkage screws after each flight for the first three flights, then about each month after that. Oh yeah - I only use the metal clips to attach them to the servos. In fact, I have a box of a dozen for replacements when I have to take one off.
I have never tried the Robart ends or the Hayes clevises, but will probably get some on my next Tower Hobbies order.
Airbusdrvr: I had ordered my Venture 60 a few years ago, after Bruce stopped and re-started production of them. I was on his "waiting list" for over a year, I think. I just got around to building it last month while re-cuperating from surgery. I watched your thread with great interest while you were doing yours; in fact, I wrote you a question regarding the hatch on yours. FYI, I am not putting on on mine, altho I did move the landing gear forward 1/2" as you did.
Thanks again for all of your comments.

I like using ball joints at the control surface end, and Z-bend at the servo end.

Scott

I like to solder a clevis on one end and use a ball link on the other. It might be overkill but it is slop free.

David

I use this method on planes up to .60 size. I like to use wooden push rods with
1/16 rod fastened to each end. On the servo end I use a z-bend and on the control
surface end solder on a threaded coupler with a nylon clevis. I like this way because
it's simple, easy to align the control surface up, and it only has to be supported
where the rod goes out the fuse.

Good ball links will outperform all the other types hands down, especially over a long time as they do not wear like clevises (the pin wears and also the hole they goe thru enlarges with time). The worst is the Z bend, they will soon become sloppy due to the wear they make on the control horns which will soon become quite enlarged. For simplicity, the L bend with the plastic keepers work okay on sport planes and do not create the wear the Z bend causes.

Z Bend. Unless something was done improperly it will never fail. That is why they are mandated as a termination in the AMA rulebook for many events.

I have had many of the solder on clevis setups brake loose on me, and would only risk using them on throttle. I agree with Rodney, the ball link setups work great and seem to be the most friction free.

The reason soldered links break is the joint is not getting hot enough, usually because it was assembled using a soldering iron. The solder melts around the opening of the clevis and then solidifies and looks like a strong joint, until..

The best way to solder a joint is with a torch. Dip the end of the rod in flux and locate the clevis onto it. Heat the clevis and wire until they are nice and hot, then touch the solder to the joint. The solder will melt instantly and be carried into the space between the wire and clevis through capillary action. Plumbers call it a "sweat joint". It is incredibly strong!