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Conference vmszoo::rc

Title:Welcome To The Radio Control Conference
Notice:dir's in 11, who's who in 4, sales in 6, auctions 19
Moderator:VMSSG::FRIEDRICHS
Created:Tue Jan 13 1987
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1706
Total number of notes:27193

1557.0. "Put nyrods in a covered model?" by CSC32::HAGERTY (Veni, Vedi, $Cmkrnli, Rebooti) Wed Sep 15 1993 01:53

    I bought a Telemaster 70 ARF from our local hobby store that somebody
    had started to put together, apparently botched (though not too badly),
    then ended up getting rid of.  Needless to say, the price was right
    :-).
    
    The problem I am having is that of control for the control surfaces.
    The original wire pushrods and those plastic tubes had been taken out, and
    there are two slots in the back, one for the rudder and one for the
    elevator.  I tried pushrods, but failed miserably since the tail
    doesn't have an opening at the end and is tapered to nearly a point.
    
    That leaves me with nyrods, I suppose.  Frankly, I'm not wild about
    them, but I don't see a good alternative.  The problem is that they
    have to be anchored, and since the ARF is already covered, I don't have
    access to the very back to anchor them.
    
    I considered encasing the nyrods in something like brass, but that
    would weigh a ton.  I'd end up putting nose weight in, and I'd rather
    not do that if I can help it.
    
    So there it is.  The dilemna.  How do you install nyrods in a plane
    that's already covered?  BTW, I admit that I didn't read through
    existing notes to see if this has been asked and answered, so I'll
    take the appropriate grief if the answer lies herein.
    
    						Dave()
    
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1557.1PushrodsLEDS::WATTWed Sep 15 1993 08:4911
    Dave,
    	I'd go with pushrods.  Cut a hole in the bottom of the fuse if you
    have to.  Noone will notice a patch there.  Also be careful to get the
    ailerons slop free.  I have seen aileron flutter problems with this
    plane.  The standard hinging is a mess.  Make sure that they won't pull
    out.  If they are marginal, rehinge the control surfaces.  Also seal
    the hinge gaps.  I'd go with servos in the wings instead of belcranks. 
    The plane flies great if you get the controls solid.
    
    Charlie
    
1557.2How about pull-pull?GAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 09:344
For the fuselage, consider putting holes on both sides and running 
pull-pull controls. Just mirror the horn on the opposite side and 
hook up the wires. You can use a piece of nyrod to snake the wires 
through initially and then remove it and connect them up.
1557.3Hard on ServosLEDS::WATTWed Sep 15 1993 10:086
    I wouldn't go pull-pull unless you have ball bearing servos.  The load
    on the output shaft will wear it out.  Pull-pull is good if you do it
    right but so are pushrods.
    
    charlie
    
1557.4GAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 10:238
I was thinking more from an ease of installation point of view but 
yes, BB servos are strongly recommended. The BB conversion kits offer 
a reasonable upgrade (Tower has 4 Universals for about $17 which fit 
the $15 JR 507s)

The problem I usually have with pushrods is getting them into the 
fuselage and out the holes on the already built planes. I guess a 
Telemaster might have a bit more headroom 8^)
1557.5Tube TrickLEDS::WATTWed Sep 15 1993 10:287
    The tubing trick will work on pushrods.  You run a piece of nyrod
    through the fuse and slip it over the pushrod end.  Then pull it back
    through and feed in the pushrod.  Works even with Y pushrods for dual
    elevators.  Many ARF's come with the tubing just for this purpose.
    
    Charlie
    
1557.6Pull-pull setupBAHTAT::EATON_NStupid English Ker-nigg-itWed Sep 15 1993 11:3323
    
    If you go pull-pull then you can use a system where you connect the
    wires to a swivelling arm, then connect the arm to the servo, you then
    have no side strain on the servo. So :
    
    	   
      wire to horn		
    -------------------------I 
    			     I------I
    	         Swivel -->  O	    O  <--- servo output arm
    			     I    
    -------------------------I <- swivelling arm 
    
    I'll never be good at ASCII graphics (sigh)
    
    In the UK Flair make a really neat moulded gizmo to do this, which
    incorporates a spring loading to keep the whole thing nice and tight.
    It also lets you get away with sloppy horn geometry. Neat product!
    
    Cheers
    
    Nigel 
    
1557.7pushrods sound goodCSC32::HAGERTYVeni, Vedi, $Cmkrnli, RebootiWed Sep 15 1993 11:3916
    From what everybody's saying, it looks like pushrods are the way to go,
    as I'm not keen on cutting into the model if I can help it.  The fuse
    is slab-sided with no opening between the bays, so I'd probably end up
    with quite a mess.
    
    Since pushrods are it, I guess my next task is to figure out how to
    make pushrods work without scraping.  The exit holes for the elevator
    and rudder are almost directly below the front of the horiz stab and
    there isn't much space to work in there. I tried using dowel rods, but
    they ended up banging together and scraping.  What would be *IDEAL*
    would be something that is a) rigid b) small in diameter and c) has a
    2-56 rod on the end.  While I'm at it, I'll wish for world peace.
    
    How can you make pushrods work in such a small space?
    
    Thanks for the help.
1557.8Small and Stiff..SHIPS::HORNBY_TSoarers are rarely SilentWed Sep 15 1993 12:489
    If you're going for push rods in a tight space then Glass or Carbon
    arrow shafts or kite sticks are worth a try the 3/16" (4-5mm) diameter
    are very stiff.
    
    Personally, I'd go for the closed loop (on Rudder at least) with the
    servo saver as described by Nigel ..(-.2 I think).  
          ...But then a Glider Guider would ..they do it all the time..
    
    Regards Trev
1557.9Arrow Shafts work WellLEDS::WATTWed Sep 15 1993 14:4811
    Dave Brown makes nice pushrod kits that come with Plastic ends.  He
    makes both fiberglass and carbon fiber shafts.  They are about 1/4 inch
    in diameter.  I hate the extra linkage in the pull-pull with a
    belcrank.  I go directly to the servo but I use double ball bearing
    servos to do the job.  My Conquest rudder has ZERO slop.  I used Kevlar
    string for the pull-pull and it's very rigid and friction free.  You
    don't need to string it that tight if you have a material that doesn't
    stretch like Kevlar.
    
    Charlie
    
1557.10Use stiff snakes!.CSTEAM::HENDERSONCompetition is Fun: Dtn 297-6180, MRO4Wed Sep 15 1993 15:099
    In a tight installation I would use a full length 256 rod and sleeve.
    Dubro sells them already packaged.
    
    To make an exit hole I use a chainsaw file. It is about 3/16" in
    diameter and is a constant thickness. It is about 12" long and this
    allows you to file a groove that will line up the cable/rod with the
    horn and servo.
    
    E.
1557.11Replace yellow with blackGAUSS::REITHJim 3D::Reith MLO1-2/c37 223-2021Wed Sep 15 1993 15:312
Sullivan makes a set now with carbon fiber inners that aren't temperature 
sensitive.
1557.12AMAZING.....ELMAGO::RMOUSERRON MOUSER, ABO/B3,552-2152Wed Sep 15 1993 18:005
    As Eric said in .10 I heartily recommend solid 2-56 rods.  Using the
    chain saw file is EXACTLY how I do it.  Doing it this way eliminates
    ALL quesswork later.  Once trimmed, always trimmed.
    
    Ron