What’s this called?

[EGB 953]

I need one of these so I can join two separate elevator surfaces. Any idea what it’s called? (See attached image). 

[Robert Cracknell]

Would a suitably sized electrical terminal block cut to length do the job?

 

 

[steve too]

An abomination.

 

VQ's instructions for a model that I have simply refer to it as a connector.

 

I bought a model 2nd hand that did something similar with a hardwood block.

 

My recommendation would be to use two mini servos, e.g. HS-82s (which is what I did in the VQ).

 

Edited December 17, 2023 by steve too

[Tim Kearsley]

Model Fixings (modelfixings.co.uk) sell them and call them dual push connectors.

[Andy Stephenson]

https://www.modelfixings.co.uk/rc_fittings.htm#dual connector

[Don Fry]

Lump of wood, drilled for wires, and locking bolts. Cheap too. 

[Paul De Tourtoulon]

Or three of these on a plank or metal strip.

[EvilC57]

I use the 3-way metal terminals from an electrical celing rose (see pic). Cheaper to buy than special 'dual push connectors', and more solid than using plastic terminal blocks. I then encase the whole assembly in epoxy once adjusted and tested.

 

Edited December 17, 2023 by EvilC57

[kc]

Aerobatic models often use a ' forked pushrod '  made by bending both wires  in to meet the central pushrod then binding and soldering.    Less chance of an elevator failure due to a loose screw?

[EGB 953]

3 hours ago, kc said:

Aerobatic models often use a ' forked pushrod '  made by bending both wires  in to meet the central pushrod then binding and soldering.    Less chance of an elevator failure due to a loose screw?

That makes sense or the suggestion of separate servos, this is for a small plane (25) so not expecting too much stress.  My soldering is pretty bad so the risk may be worse that way. 

[john stones 1 - Moderator]

I don't mind those connectors, pretty sturdy and you can can give the studs a good turn, used on quite a few artf's I've owned and never failed me.

[Paul De Tourtoulon]

This is what I do when using carbon rods that you can't use screws on.

[Brian Cooper]

Forget "bodge" connectors. . Use two servos. 

[Nigel R]

I'd probably bend the ends of that wire over at 90 deg, glue / bind them to a hard balsa block or short length of hardwood dowell, then bind a third short length to go to the servo. Nylon thread, epoxy, some scrap wood, would take only a few minutes to do.

 

 

Certainly permanent enough for a 25 size airframe.

 

Effectively, a (very very short) dual pushrod - which were common (as kc noted) on old 60 size aerobatic airframes in 70s/80s/90s.

 

Two micro servos also works fine, but the single standard servo install is already there.

[EGB 953]

2 hours ago, Nigel R said:

I'd probably bend the ends of that wire over at 90 deg, glue / bind them to a hard balsa block or short length of hardwood dowell, then bind a third short length to go to the servo. Nylon thread, epoxy, some scrap wood, would take only a few minutes to do.

 

 

Certainly permanent enough for a 25 size airframe.

 

Effectively, a (very very short) dual pushrod - which were common (as kc noted) on old 60 size aerobatic airframes in 70s/80s/90s.

 

Two micro servos also works fine, but the single standard servo install is already there.

This looks a pretty practical option and your explanation is much appreciated. getting two elevators to be perfectly aligned might be very difficult though, any suggestions on how i might go about it?

[Engine Doctor]

9 minutes ago, EGB 953 said:

This looks a pretty practical option and your explanation is much appreciated. getting two elevators to be perfectly aligned might be very difficult though, any suggestions on how i might go about it?

If you get the connector close ennough any fine adjustments can be made at the clevise on the elevators ? 

[Nigel R]

As ED says. I've assumed there are adjustable clevis at the elevator end of the pushrods.

[EGB 953]

This is a fantastic forum - to have access to the collective wisdom of you all - it is greatly appreciated.

 

[Konrad]

While I agree with the sentiments of most of these posts. That device is called a tie bar. Well, in some of the more polite engineering circles I run in. It does have its uses and should be kept in the back of ones mind as a valuable concept to solve a problem.

[Don Fry]

Wot device. I do Roman engineering. Explain.

[Rich Griff]

Wiffeltree compensator..mind you I was young and dad did have a *sence of humour* bless him.

 

Horse and cart, Roman chariot, handbrakes etc. etc. etc........

[Konrad]

17 minutes ago, Don Fry said:

Wot device. I do Roman engineering. Explain.

??? I did a search and didn't find a definition for "Wot" or "Roman Engineering" ???

 

The OP asked for the nomenclature of the device shown. I didn't see one given.

[Ron Gray]

13 hours ago, Don Fry said:

Wot device. I do Roman engineering. Explain.

Split elevator, 2 into 1 connector / balance bar.

[Paul De Tourtoulon]

What about 2 in 1 elevator divider,,, sounds good to me.

[Konrad]

I'd like to caution against calling a device by its application (elevator or flap joiner). Rather the nomenclature should describe the function; Tie Bar, Joiner or Splitter.

 

As this is under engineering I'm a bit surprised that the short coming of the way this is shown in the OP's and other posts hasn't been discussed.

 

As shown the rotation of the servo arm, side to side, will bias (favor) one push rod over the other. This is why some many of the post are using some form of derogatory name for the device. These tie bars have historically caused all sorts of rolling issue with the elevator or flaps, that use these tie bars, are actuated.

 

The proper way to orient the servo output shaft is to rotate the axis  90°. In the proper orientation for a split control surface the servo arm arc will move the tie bar up or down while NOT biasing any one push rod. 

 

Time and time again I'm shocked at how often designer/builder forgo solid engineering mechanics. Some might say that this was often done out of expedience as the cost of servos or mixing circuits was far too expensive at the time of the design.

 

Unfortunately I've just built a new 2022 design 4 meter alpine glider where the designer has shown total disregard for solid mechanics. This cripples the design!