MK Dual Elavator Bellcrank & Pushrod?

Fri Feb 4 10:39:10 AKST 2005

Brian, I didn't realize that some outer tubes were different plastic that  
PTFE Teflon. Carbon fiber normally has a low coefficent of friction,  however, 
the binder material is usually a vinyl ester  which has high  cof.  When that 
comes in contact with most common plastics like nylon for  example, friction 
can get too much for our purposes.

Best outer sheath material is PTFE (teflon), bar none. PTFE has the lowest  
CoF of any plastic. Only way to make it better is to extrude teflon with ridges 
 in the ID, reducing the contact area (sort of reverse nyrod). 

BTW, Hobby Lobby sells steel threaded couplers (not the more common brass  we 
see from others) that will work great with this size carbon rod. Slip the rod 
 in place and Epoxy it in.

Matt

 n:34:54 PM Eastern Standard Time, auto7832 at bellsouth.net  writes:

Speaking of the CF push rod set ups, I would like  to share a little info. I 
just finished installing my second CF. elev. pushrod  assem. in a Impact, the 
first was in my Majestic. In the Majestic I got the  DEPS setup from CST seen 
here _http://www.cstsales.com/CCPush-rodKits.htm_ 
(http://www.cstsales.com/CCPush-rodKits.htm) 
This kit comes with a thin walled Teflon outer  case and even with a slight 
bow or arc in the assem. the system remains  Very friction free.
For the Impact I purchased the kit from  Central and it comes with plastic 
outer cases and these were difficult to  get smooth and friction free, the 
slightest bend or arc made the movement very  stiff and as a matter of fact, I 
could not even use them and ended up using  hollow CF. rod for the outer case 
which worked very well but slight bends or  arcs are out of the question. Just my 
personal experience, yours may  differ.

----- Original Message ----- 
From:  _Wayne Galligan_ (mailto:wgalligan at goodsonacura.com)  
To: _discussion at nsrca.org_ (mailto:discussion at nsrca.org)  
Sent: Thursday, February 03, 2005 4:49  PM
Subject: Re: MK Dual Elavator Bellcrank  & Pushrod?

I am in the middle of a major on mine  and if it shows any signs of fatigue 
am going with the pull/pull like Matt  described.  I all ready have my servo 
sideways so why not?  And  save a few grams in the process.
Still the slickest way and most worry free is  the .070 dual c.f. rods.   And 
that will be the way I set up any  new plane in the future.

WG

----- Original Message ----- 
From:  _Dean  Pappas_ (mailto:d.pappas at kodeos.com)  
To: _discussion at nsrca.org_ (mailto:discussion at nsrca.org)  
Sent: Thursday, February 03, 2005  3:25 PM
Subject: RE: MK Dual Elavator  Bellcrank & Pushrod?

That makes you want to run cables in full length guide  tubes.

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
_d.pappas at kodeos.com_ (mailto:d.pappas at kodeos.com)   
-----Original Message-----
From: _discussion-request at nsrca.org_ (mailto:discussion-request at nsrca.org)   
[mailto:discussion-request at nsrca.org]On Behalf Of Wayne  Galligan
Sent: Thursday, February 03, 2005 4:24  PM
To: discussion at nsrca.org
Subject: Re: MK Dual  Elavator Bellcrank & Pushrod?

I took a (2) pieces of foam about 2"sq x 4"  long and pushed them onto the 
c.f rod and placed them about 6 inches  from each end.   I could then move the 
pieces back and forth  to tune out the harmonic resonants.  Just watch the rod 
at various  engine speeds to see what it does.  When it vibrates it is amazing 
 that any of them would hold together. 

Wayne G.

 ----- Original Message ----- 
From:  _Rick Wallace_ (mailto:rickwallace45 at hotmail.com)  
To: _discussion at nsrca.org_ (mailto:discussion at nsrca.org)  
Sent: Thursday, February 03, 2005  11:43 AM
Subject: Re: MK Dual Elavator  Bellcrank & Pushrod?

Agree w/ John about using foam as a vibration damper. Also, someone  much 
wiser than me pointed out that whatever is installed should NOT  be halfway, 1/4 
way, or any reasonable fraction of the pushrod  length because these may end 
up as stationary nodes in the  vibrating rod, and end up doing no good.  
Rick

>From: "John Ferrell" <_johnferrell at earthlink.net_ 
(mailto:johnferrell at earthlink.net) >   

>Reply-To: discussion at nsrca.org  

>To: <discussion at nsrca.org>  

>Subject: Re: MK Dual Elavator Bellcrank & Pushrod?  

>Date: Thu, 3 Feb 2005 09:07:36 -0500  

>  

>Be very careful about alignment. An extra bushing on  the shaft can cause a 
lock up under vibration.  

>A foam rubber damper is safer. It can be as simple as a  wad of foam or as 
complicated as another bulkhead.  

>  

>John Ferrell  

>http://DixieNC.US  

>  

>   ----- Original Message -----  

>   From: Jerry Wilson  

>   To: discussion at nsrca.org  

>   Sent: Wednesday, February 02, 2005 10:59  PM  

>   Subject: MK Dual Elavator Bellcrank &  Pushrod?  

>  

>  

>   I've mounted the bellcrank and will use  Central's carbon fiber push rod. 
 The pushrod length from  servo to crank is about 28".  

>  

>  

>  

>   Is it necessary to install a support of  the rod  halfway down the 
fuselage to prevent  flexing.  And if so does anyone have a simple way of doing  
this inside a fiberglass fuselage?  

>  

>  

>  

>   TIA  

>  

>   Jerry  

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