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Author Topic: RM pushrod question  (Read 709 times)

Offline Paul Taylor

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RM pushrod question
« on: May 15, 2023, 02:01:59 PM »
So how do most folks get the push rod to clear the wing spar?
Do I cut a groove in the spar?
Paul
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Online fred cesquim

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Re: RM pushrod question
« Reply #1 on: May 15, 2023, 02:07:17 PM »
i use a straight push rod angled and with ball link on the bellcrank

Offline Ty Marcucci

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Re: RM pushrod question
« Reply #2 on: May 15, 2023, 02:08:27 PM »
It's ugly, but more often than not,  I used a 90 degree bend..On a Ringmaster who cared? I worked. D>K
Ty Marcucci

Offline Paul Taylor

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Re: RM pushrod question
« Reply #3 on: May 15, 2023, 02:19:26 PM »
i use a straight push rod angled and with ball link on the bellcrank

That wing does not have the rear spar. That’s the way I do it too. But this RM has the spar in the wrong place. 🤪
Paul
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Offline Paul Taylor

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Re: RM pushrod question
« Reply #4 on: May 15, 2023, 02:20:34 PM »
It's ugly, but more often than not,  I used a 90 degree bend..On a Ringmaster who cared? I worked. D>K

Thanks Ty. That’s about what it takes. 😝
Paul
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Offline Ken Culbertson

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Re: RM pushrod question
« Reply #5 on: May 15, 2023, 02:43:29 PM »
A ball link with a few washers under it will move the pushrod up enough to clear the spar.  If you need to notch the spar some to clear, that is OK.  Just add a doubler around the cut.  I don't think the spar is adding much to the center section strength, especially if you were to switch to a floating setup.  I am opposed to any bends in pushrods unless it is totally unavoidable.

Ken
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Offline Paul Taylor

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Re: RM pushrod question
« Reply #6 on: May 15, 2023, 02:50:12 PM »
A ball link with a few washers under it will move the pushrod up enough to clear the spar.  If you need to notch the spar some to clear, that is OK.  Just add a doubler around the cut.  I don't think the spar is adding much to the center section strength, especially if you were to switch to a floating setup.  I am opposed to any bends in pushrods unless it is totally unavoidable.

Ken
Thanks Ken.
I don’t like bend’s either. I do like the idea of floating the BC up. Putting on my thinking cap. 🧢
Paul
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Online fred cesquim

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Re: RM pushrod question
« Reply #7 on: May 15, 2023, 04:51:56 PM »
That wing does not have the rear spar. That’s the way I do it too. But this RM has the spar in the wrong place. 🤪
i know, have built a few. ;D you can still use the same method of the ball link, it will raise the pushrod past the rear spar

Offline John Carrodus

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Re: RM pushrod question
« Reply #8 on: May 15, 2023, 05:12:27 PM »
Lift the bellcrank slightly and bend the pushrod up at rightangles to clear. A boo boo on the plan I'd suggest. Pusrod might leave wing a bit more towards the center rather than closer to trailing edge. Whatever works. CL is all about problem solving.

Offline doug coursey

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Re: RM pushrod question
« Reply #9 on: May 16, 2023, 07:21:49 AM »
I HAVE BENT THE WIRE AND THEN PUT A CARBON ROD OVER IT CUTTING IT AT THE BEND THEN JB WELD IT,THAT WAY YOU CAN USE A CARON ROD FOR STRENGTH..PUT CARBON TUBE ON BEFORE YOU BEND IT
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Offline Pat Johnston

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Re: RM pushrod question
« Reply #10 on: May 16, 2023, 08:50:14 AM »
I'll attach my plans PDF files for the Ringmaster Gold I drew up in 2008.  This shows the pushrod easily missing the spar.  setting up the controls this way will remove all the problems associated with the spar.
Pat Johnston
Idaho Skunk Works

Offline Gaylord D Elling

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Re: RM pushrod question
« Reply #11 on: May 16, 2023, 09:20:10 AM »
Du Bro makes a small stand off that you use on the bellcank along with small ball link and carbon fiber pushrod, make a small bend in the titanium insert/carbon fiber pushrod junction to clear spar. It is not a big deal. I have made many excellent flying Pat Johnston RM's, never had a failure. The one I have now is 6 years old, and I fly it in nasty wind at contests when I don't want to sacrifice a nicer airplane, no failures. I would be much more nervous nothing the spar.Hope this helps. H^^


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