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General control line discussion => Open Forum => Topic started by: rich gorrill on November 21, 2013, 12:39:33 PM
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I hope this isn't too stupid a question but I am using Dubro ball links for the first time. They come in four pieces, the link the bolt the nut and the spacer, my question is where does the tapered brass spacer go and do you have to use it. It seems it is there to center the control pushrod. Any help would be appreciated.
Thanks, Rich
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I hope this isn't too stupid a question but I am using Dubro ball links for the first time. They come in four pieces, the link the bolt the nut and the spacer, my question is where does the tapered brass spacer go and do you have to use it. It seems it is there to center the control pushrod. Any help would be appreciated.
Thanks, Rich
The tapered spacer goes on the bellcrank ball link 4/40 mount to raise the ball link, and with the taper facing up towards underside the ball link, stops the ball link flange from any drag or rubbing because of the steep angle to the flap horn. (at least for our use, I'm sure it's for a totally different but similar reason/use for the R/C guys)
This allows you a much greater possible angle for the short pushrod than otherwise possible without the brass taper fitting.
Hope that makes sense and helps,
EricV
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Thanks Eric that makes sense. But how about if I am using the ball link on the flap or elevator control horn. I want to use them there for fine tuning using the 4-40 connector. Just to clarify they are being used on a profile ship with flaps.
Rich
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Keep ball links on the bellcrank only, use only one flap horn. Do not use R/C clevis', they break, wobble, come unscrewed. Do not use bolt on nylon horns, they bend, break and don't last forever.
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While I like the flexibility that layout gives you, I would hate the flexibility that layout gives you... if you get my drift. If that's a typical 3/32" horn, the spongy elevator control would drive me nuts I would think. Even with 1/8" horns, I don't think I'd want to try that on a heavy 60 size ship in any kind of wind.
EricV
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Refer to reply #3.
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Simple solution and gives more adjustment possibilities. I like it. If flexibility is a concern you could use aluminum horns.
Joe
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For an OS35S powered profile sport-stunt ship like this it works fine. Control feel and responsiveness improved as compared to the standard two pushrods to the flap horn set-up that this model originally had.
A picture is worth a thousand words. The one on the right is the ball link. What it doesn't show is the 4/40 washer under the head of the screw as a safety in case the ball link fails. It can be problematic to put two ball links on one horn. That is one reason why I set up my controls as shown in profile models. Elevator horn ball links can be set up the same way although I prefer 4/40 type quick links for that attachement. Thanks to Pat Johnston for this idea.8)
IMHO
I am guessing that your definition of "works fine" might diverge from mine. If something improved I think it was an accident in freeing up your original control setup or getting the rod lengths adjusted better.
This is NOT a better mousetrap!
You have a springy torsion bar between the two control horns. Not better, not no way, not no how. It is not "problematic" to put two links on one horn.
With due respect, no one should copy this.
Kim.
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Using 1/8" music wire on a 40 sized ship the link would fairly robust. I still like it.
Joe
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Refer to reply #3.
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IMHO
I am guessing that your definition of "works fine" might diverge from mine. If something improved I think it was an accident in freeing up your original control setup or getting the rod lengths adjusted better.
This is NOT a better mousetrap!
You have a springy torsion bar between the two control horns. Not better, not no way, not no how. It is not "problematic" to put two links on one horn.
With due respect, no one should copy this.
Kim.
Kim, it may not be a better mousetrap, but believe me when Pete says "works fine", it does. I have flown that model and there is no flex problem. Flight controls seem very firm and positive The airplane is simply not large or powerful enough to create any noticeable problem.
Besides, he put the pic up to show how a ball link assembly goes together. Not for critiques on his control system.
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Thanks Clint, that model (Brodak P-51) was given to another flier. He too likes the way it flies. 8)
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I thought today, "Knovember" (sic) 21, was supposed to be "Pick on Pete Cunha Day"? WTH? LL~ Steve
PS: I'd avoid bolt-on control horns, especially nylon ones, see nothing to be gained by having twin horns, and wouldn't use an R/C clevis from the LHS anywhere in the system.
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Refer to reply #3. 8)
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For a better explanation of why this control setup works check out Pat Johnston's post from Dec. 29, 2011 - "New Profile Mustang "B" Model for Tom Dixon". 8)
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For a better explanation of why this control setup works check out Pat Johnston's post from Dec. 29, 2011 - "New Profile Mustang "B" Model for Tom Dixon". It can be easily found using the search function of the forum. 8)
Every time I try to use the search function it asks me if I want to search for Tom Dioxin. Does it know something I don't? :X
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I typed in: "Pat Johnston Tom Dixon B Model Mustang" and it came up as the third entry. Ignore the "Dioxin" reference and scroll down. The search feature is just being a Smart A#*. Scroll down to reply "12" for the explanation of the two horn control setup (It's not shown on the Mustang plans). 8)
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Here's a tip for the sake of good search results, I would go to Google and type, "ball links site:stunthanger.com"
You can do that for any site, leaving off the "http and www" and all that junk.
The results will link you to archived topics, but you can quickly get to the original topic like this: My search turned up this URL: "http://stunthanger.com/smf/index.php?topic=1118.0;wap2"
After you go from Google to that topic, in the address bar, double click the "wap2" to highlite it, press delete and enter, and you're in the original thread.
It's easier than I make it sound. Just thought I'd throw that in, I hope it helps someone who searches a lot.
Rusty
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For a better explanation of why this control setup works check out Pat Johnston's post from Dec. 29, 2011 - "New Profile Mustang "B" Model for Tom Dixon". It can be easily found using the search function of the forum. 8)
Here is the link
http://stunthanger.com/smf/index.php?topic=24619.0
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I had some initial concerns about this setup also. Flight testing did not prove them out. Try it on a sport plane, you can always switch back if you don't like it. Prior to the change, controls were free, aircraft was in trim, not my first rodeo (or my original idea). It does work well. Each to his own. 8)
Sorry Guys, but I have to vehemently agree with Kim Doherty about this set up...If it works better you either have a great imagination, or simply cured some other problem with the "fix".
Using a second torsion rod (even 1/8 diameter wire) has to be much wimpier at the elevator and the flaps than a conventional setup.
Like Kim I would discourage anyone considering using this kind of setup on anything bigger than about 300 Sq in, and anything that you might want to fly in windy conditions...there are enough reasons to crash in the wind without having wimpy controls.
Randy Cuberly
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Didn't want to start a controversy or be accused of putting out bad advice so responses have been modified. Sorry to mess up the thread, my bad. Moderator: Edit as you see fit.