Electriceddie

Hey guys,

I was wondering what some of the most recent or cutting edge ways guys are setting up their linkages for airplanes. Using 2-56 and 4-40 steel rods, Ny-Rods, EZ- connectors Z-bends etc. What kinds of linkages are being used mostly out there in RC land. Are guys still using primarilary Z-bends at the servo ends and clevis's at the control end. I would like to hear what some of the ways guys are connecting the linkages up. Also hinges, is the Zap hinge the way to go? Hinge points? Any new techniques out there. Basically the what types of linkages would you use on any typical .40 to .90 size / 55" to 72" type airplane. What set-ups offer the least amount of friction? What set-up would you use?

Good luck

Thanks

Ed

alan0899

G'day Ed,
I only use clevises & ball links, ball links on the servo & clevises on the control surface, with fuel tube to stop them opening.
On a 40 to 90 sized plane 2-56 is OK, but for aerobatics & 90 size I would go 4-40.
CA hinges are fine, if used correctly & pinned.

bkdavy

My Feedback: (1)

I use the 2-56 rods most of the time. Great Planes makes a "faslink" connector that I like to use at the servo end, and then put a metal clevis on the Control surface end. I like the faslinks because they're quick and durable. No Z-bending required. Just a 90 degree bend, then trim it, put it through the servo horn, and snap it on the rod.

Brad

Charlie P.

Those 90º links are called "E/Z Links" (see image). I think they're the best thing since Hershey Kisses. Unfortunately, the name is close to the "EZ Connectors" that are dirt naps waiting to happen. Several of our designated training pilots will not buddy-box a plane that uses them as they are that set against them. The AMA won't allow them to be used on control surfaces in some events I am told (though I have been unable to find that in writing on the AMA website). Those I only trust for throttle linkages; and then only if it's a bear of an installation and hard to rig otherwise.

The "Kwik Links" are something else - a clevis with a spring catch instead of fuel tube or other methods.

I like the ball link on the servo end and a metal clevis on the other, though for "rough" sport models I don't get that fancy. The E/Z Link and a screw clevis .40 size) or a solder clevis/screw clevis combo (.50 to .70). Also depends a lot on what I have on hand. ;-)

If it's possible, a pull-pull rudder is nice. Not worth the effort in many models.

Sullivan Gold-n-Rods and Cables make life simpler, but the good old dowel with a 2-56 or 4-40 rod that has a 1/4" bent end that's stuck in a hole 1-1/2" from either end of a dowel (get fancy and make a groove for the wire) and wrapped with thread and finally covered with epoxy is a lasting solution. I use 11/32" cedar arrow shafts as they are strong and light.

Hinges - CA for models under eight pounds or so. DuBro pinned HD for larger.

Woodpile

Alan,

I don't know how common it is and I'll admit it was the first time I'd seen it happen, but I lost a plane to fuel tubing holding the clevis shut. It was in a modified Ugly Stik with a pull-pull rudder and the clevis pulled right off one side during a snap roll. With no way to control the rudder in a crosswind, she rolled over and died. Since then, I only use Sullivan clevises with the retaining clip. Just something to think about...

Ed

rclement

My Feedback: (1)

Here's a copy of a post I just did this morning in the 3D section.... Here's my set up. I make my own rods with ball links or clevis's.
Here's the carbon fiber rod I use... CF Rod
And what I do is to carefully drill out the end of the rod with a drill bit (be carefull not to split the rod) then insert the 2-56 rod into the end of the rod to fit check. You can get some aluminum tube from the LHS that will just fit over the CF rod. Use a short section to keep the rod end from splitting. Once you get it all cut to length put some JB weld into use to glue the 2-56 rod into CF rod. Have the 2-56 rod sticking out of the CF rod long enough to screw into the clevis or ball link. I put the rods into the oven at the warmest setting (170 degrees) and cook them for about 15 minutes to set the JB weld. When they're set up I screw the ball ends or clevis's onto the threaded part and adjust to length. It's cheap and easy to do. Here's a pic from my U Can Do and Mayhem. [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXD610&P=7]ball link[/link]
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXWH34&P=7]clevis[/link]
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJDP7&P=7]carbon fiber rod[/link]

alan0899

G'day Ed,
Which part broke, the clevis pin or the fuel tube retainer?
Ya got me curious now!

digital_trucker

Monokote hinges work very well, but they must be properly done. (Black Baron film doesn't hold up either.) I've used Monokote hinges on an Ultra Sport 40 powered by a HP .61 - insanely overpowered and a real rocket - set up with high throws, too. To do them properly is a 4-step process.

1) cut 1' squares of Monokote. Overlap them 1/4" glue-side-to-glue-side and iron them together.

2) cover the mating surfaces first with a 1/2" strip the full length

3) iron the mated squares full length in a criss-cross pattern

4) cover the rest as usual.

You get an absolutely slop- and gap-free hinge line that is immensely strong. Try it and see...if you can pull it apart you're more of a man than I.

AA5BY

I use Z bends at servo and usually metal clevis (Dubro) at horns. I agree that if a clevis lock breaks... the tubing will not always hold it on but given the percentages, the tubing lock is still worth the effort. I've only had one metal clevis fail and that while stretching it to install or take off.

I like Z bends cuz their cheap though they are not 100 percent safe. Years ago, Z bends could even be used on 1/16 music wire but I've found modern music wire to fail when trying to make sharp bends and have personally ascribed using it to be risky.

Z bends on 2-56 rods are easy to do and work great but require the control arm hole to be enlarged slightly and this is where Z bend problems more often happen, the hole gets enlarged too much by an inappropriate drill bit and flutter results. Years ago, if without a proper drill bit, I've been known to heat the wire and size the hole with it.

Z bend pliers are easy to make from a small duck bill plier. These have a flat head so can be center punched and drilled easily. Drill a hole the size of the wire through one of the duck bills about 1/8 in from the end. To use, insert the wire into the hole, bend 90 deg, close the plier and bend around other bill slightly more than 90 deg. Open plier and remove. After just a few bends, one can precisely determine how much rod to add for the bend. I have this marked on the pliers.

Electriceddie

Hey Guys,

The ball link on the servo horn is and interesting idea, but my only concern is it disconnecting. Would you use it on any type of .40 to .60 size plane? Ex. Super sportster, Ultrasport, 60" size Extra 300, 60" size Cap etc. What about using them on Q-500 doing aroun 100+ speeds. I would assume a set up of Ball link at the servo end and a clevis with fuel tubing slid over it for safety. Would there be any concerns there for the ball link loosening up, breaking , snaping off etc. from stress? I have usually set up airplanes with Z-bends at the servo ends and nylon or steel clevis's with fuel tubing over the clevis for safety.

Thanks guys

Keep the ideas coming.........

k3 valley flyer

My Feedback: (18)

I have used EZ connectors at servo horn for over 20 years on some 50 planes, up to 150 glow sized planes, but most were 40 to 60 glow at 6 to 8 lbs. Have never had one fail. I use the metal clip not the plastic ones, and leave about 1/2 inch of the wire pushrod sticking past the set screw. Tighten the set screw as tight as possible, rods are piano wire in plastic tubes. Again no problems. Just my experience not an endorsement or recomendation.

rclement

My Feedback: (1)

I have the ball links in use on 40 size up to 90 size and fell confident that they are very secure. You don't have any slop in the travel with ball links. You won't need fuel tubing to for safety. There is a screw/bolt with a nut that holds it together so I just put some epoxy on the end of the bolt to make sure the nut can't come off. I would think that even at 100 miles and hour something else is going to break before the bolt will break. I use to test bolts and other fasteners for Boeing and doubt that even those little things will break.

Trogdor the Burninator

I like the EZ connectors also but I once tried for 45 minutes to get that #(*@&$*(@#$ metal clip on and just couldn't do it! What's the secret???

Woodpile

Alan,

Actually neither broke, the fuel tubing opened enough to let the control horn go on one side. It was a Dubro clevis, the kind without any notch or retaining device. It did make for a very interesting 7 seconds though... As I said, I'm not sure how common this is, but I figure since I have to buy clevises any way, I might as well buy the ones with retaining clips and not wonder...

Hope your summer is going better than our winter... -11C with 25 knot winds on the weekends. Brrrrrrrrrrrrrrrrrrrrrrrr.


Ed

Birman

Drill a small close to the edge of a piece of 1" pine. Clamp the pine close to the edge of your work bench. Set the metal push nut over the hole in the pine. Now carefully place the EZ link over the push nut (a pair of hemostats works well for this) and take a pair of pliers to the top of the EZ link and the bottom of the pine board. You will be able to "feel" the EZ link enter the push nut. From that point, take it easy so as not to make the nut too tight aganist the servo arm.

BillyGoat

I whole heartily agree with Charlie P. regarding E/Z connectors. They should not be used on flying surface linkages. Period!

An E/Z connector can fail in two ways. The set screw can come loose or the back can come off letting connector depart from the servo arm. There are so many other options available that enormously decrease the chance of failure.

The following link is the most comprehensive look at all the connectors available I’ve seen anywhere. The author also charts connectors from best to worst. (Any guesses what is on the worst end?)

http://www.airfieldmodels.com/inform...d_linkages.htm

k3 valley flyer

My Feedback: (18)

Worked for me for over 20 years.

Electriceddie

k3 valley flyer,


I think your extremely lucky using the EZ-connector. I agree with BillyGoat. I would,and only do use them on the throttle linkage at the servo end.

At my field in Long Island your plane would be grounded by the safety officer for using them on any servo connected to a control surface. They may have worked for you in the past without any issues but I think that the risk factor far exceeds the safety factor. There is to much risk for wear or failure. Now I am not conservative in my flying by any means. I will be the first one to get up in the air and do voilent snaps, blenders, spins and fly inverterd off the ground at 75MPH. As I stsated before, I usually use Z-bends on the Ail, Elev, and Rudder at the servo ends, and steel or nylon clevis's with fuel tubing (or the spring versions) at the control surface ends. On the throttle the EZ-connector at the servo end and a nylon clevis if the carb linkage is metal. I like the idea of the ball linkage and will most likely try that on my latest project on the servo ends of the control surfaces. I would also like to thank all you guys for your suggestions and points made.


Keep the ideas flowing.

Thanks

Ed

BillyGoat

For E/Z connectors used on flying surfaces, even if you remove the chance of failure from the equation, the fact that they become sloppy over time still makes them an undesirable option. Slop in a linkage system opens up a whole bunch of other evils.

k3 valley flyer

My Feedback: (18)

Yes, I only use them at the servo, not the contron horn on the surface. Have you guys ever tried them? If you have ever tried to remove the metal clip you would know the only way to get them off is to cut them off. As for wear the only part that moves is the prong that goes through the servo horn hole, it doesn't wear any more that anything else you put through the horn, like the wire of the z bend. Alot of times when you try to remove one from the push rod wire that has had the set screw tightened well, even after removing the set screw, it won't come off. Many times have had to pull out the push rod out of the plane to be able to get the EZ connect off. They must not work though, guess that is why several hobby shops I go to are constantly sold out of the bulk bags of them. I love the many myths that exist in this hobby.

Electriceddie

Hey there k3 valley flyer


There was an article a few months back in (MAN or the AMA Mag) where I guy had EZ-Connector on an elevator servo and after several flights (over 100) the plane crashed. I wish I could remember the issue number. The reason was an EZ connector on the servo end of the elevator. Upon close inspection vibration caused the metal clip to chew thru the soft copper/metal post until it broke. The the EZ-connector then fell out of the servo, causing no elevator control. I am not saying that I don't like them, they just need to be used caution on certain control surfaces. I would never use it on an elevator for sure. I believe there also are other methods which would be safer and that would have less disadvantages.


Ed

k3 valley flyer

My Feedback: (18)

I don't use them on gas engine planes or on larger 4 strokes if they vibrate alot. Still I wonder if post broke from vibration or crash impact, or if it had been reused and moved from one servo horn to another. Post can be weakened if one removes the clip incorrectly. To each his own poison.

mikenlapaz

The 2-56 you insert, are you just using short sections of fully threaded all-thread glued into both ends of the carbon rod?
A tight wrap of thread on the ends of the carbon rod takes care of it splitting out, I use Spyderwire (kevalr fishing line) and then abit of CA.
A thin section of bamboo skewer inserted in tube with a wipe of poly glue will aid the carbon tube in compression end loading. Lighter than continuous metal rod.

Carbon rod pictured with exterior bamboo support was stiff enough to bend a short (1") 2-56 end section and push out the servo screws in dorked flight.

SamD

Paul's site it great and with rare exception, I agree with everything put forth. But those Z-bends... As I've said, many, many times, we don't use 'em on full size airplanes and I have no intention of using them on model airplanes. As soon as they're shoved through the holes of the servo arm and control horns, the holes become elongated. To further compound the issue, they seem to always be used in applications where the servo axis and control surface axis are 90 degrees to one another, thus creating a binding condition. The easy links eliminate the problem with elongated holes and are a step in the right direction- as long as the axis's of control are on the same plane. The quick connectors are- arguably- an abomination suitable for throttle linkages only but people will protest to the end they're great and I suppose it's hard to argue with success- or failure- as the case may be.

Ball links & clevis's are my preferred choice with the following ball links being my choice if I have them on hand: http://www.bennettbuilt.com/page7.htm The ball & bolt are one piece eliminating the extra hardware associated with typical ball links. Expensive, yes, nice- absolutely. Combined with Central Hobbies CF pushrod & titanium ends, it's a combination hard to beat- but mighty expensive.

digital_trucker

I've used a simple 90 degree bend at the servo end and a wheel collar retainer (an L-bend)...never had one of those fail. I also used Loctite on the collar's setscrew. Like Z-bends though, it's only good if you have a straight shot with the pushrod - otherwise it'll bind on ya.