Elev. Pull pull Question

[gene.maurice at comcast.net]

Try this on...........
Set the post where you want it, say 3/8 - 1/2 inch back from the hinge line. Now redrill and trim the 3/4" control horn to put the clevis on the hinge line. Only use what you need. No matter what the length of the control horn it puts stress on the molded plastic, have to presume its strong enough to take the load.    

--
Gene Maurice 
gene.maurice at comcast.net 
Plano, TX

-------------- Original message -------------- 

Eddie,
Welcome to D6.  You already were a D36'er but now your assimilation is complete.

I could have saved you the agony.  Tried to do the same thing about 6 months ago with the same outcome.  I wanted them to screw to my own 6-32 threaded rods so I could set the rod 3/4" behind the hinge line.  Paid the big bucks for the set and used the long arms anyways.  HOWEVER, it didn't work out.  The long 3/4" reach of these "overhang" pieces looked fine with my rudder at neutral, but when the surface deflected they formed a weird angle with the pull-pull cable and almost hit the fuse.  I didn't like the look.  I no longer think these are the cats meow. The fix was to use the small white nylon old-style pieces but offset the control arm at the servo end.  Looks better and no weird stress angles on the cables.
--Lance

----- Original Message ----- 
From: Eddie Batchelor 
To: discussion at nsrca.org 
Sent: Monday, November 29, 2004 10:06 AM
Subject: RE: Elev. Pull pull Question


I contacted Dubro wanting to purchase only the plastic overhang piece as I probably won't ever use the bolts and didn't wish to pay for the entire unit. They beat around the bush for almost 3 months before finally refusing to sell them to me.  The first answer I was given was it would have to be a minumum of 50. I said no problem ,what would the cost for 50 be. Then they responded stating they didn't sell the parts individually.

I sure would like to locate such a part by someone. Most all others seem quite short.

Any ideas would be quite welcome?
Eddie

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Dean Pappas
Sent: Monday, November 29, 2004 10:43 AM
To: discussion at nsrca.org
Subject: RE: Elev. Pull pull Question


Hello Bob,
Go buy some DuBro # 867 control horns. They have almost 3/4" of overhang between the bolt and the little hole for the clevis, in the little screw-on pieces.
Use those pieces, but set the bolt and nut aside, and see if the little holes line up with the center of the hinges.
If not, then drill new holes in the black plastic bits so that they do line up: one straight line through both holes and the center of the hinge.
Now when you get the horns all the same length, it will be much easier to get the throws matched in both directions.
This is absolutely necessary for matching two elevator halves properly, but is also a good idea for rudders.
The problem with the stock setup is that the cables slacken at the ends, and tighten at neutral.
While this might sound like a good thing, it is awful: the servo has to fight the tightening cables as the surface comes closer to neutral,
then as it gets there, the surface may try to "spring" to the opposite direction.
The servo and gear train will prematurely beat themselves up chasing this problem.
You want the cable tension to be almost constant throughout the throw.
There will be pictures of this when I get the Excelleron review out the door.
One of the previous posts pointed to a website that showed the proper geometry.
DuBro and Rocket City both make parts that are useful, for this problem.

Check DuBro.com and put #867 into their search engine, you can see the lonng overhang part. It's either 5/8" or 3/4" from bolt to clevis hole.

Later,

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 
-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Bob Pastorello
Sent: Friday, November 26, 2004 8:58 AM
To: NSRCA
Subject: Elev. Pull pull Question


May seem obvious, but I could use some help here....setting up my Excelleron, centers are okay, cable tensions are pretty close, centering is good.  Up elevator is fine, on Down elevator, ONE elevator moves farther, but they track together except at the endpoint, as close as I can tell.

Anyone have suggestions on how I'd fine tune this out...??
Hope everyone had a great T-day!!

Bob Pastorello
NSRCA 199  AMA 46373
rcaerobob at cox.net
www.rcaerobats.net
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20041130/f5eda337/attachment-0001.html