[NSRCA-discussion] wing tube sleeve hole

[george w. kennie]

When I first tried to do this on my own, I made a jig that I fastened to the front of the bench that my drill press was mounted on and rotated the press head to the back side of the shaft so that it overhung the bench side and drilled the hole vertically with a spade bit and yes it worked, but I had foam beads all over the house. They were in the kitchen, the bathroom, I even had them in my bed ( it's amazing what my wife puts up with ).
Then I purchased a KISS unit from Sam Turner and discovered his method for gluing a piece of sandpaper to the end of a 7/8ths dia. tube. I then built an alignment jig with adjustable length feet at the four corners so I could set the dihedral angle and that held the tube at 90 degrees to the root rib and hand drilled the hole to the depth marked on the 7/8ths tube and voila, perfect hole !
It was an acceptable method, but I no longer build foamcore wings as I can achieve significantly lighter panels going built-up. I do, however, like the sound of Lance's coring method so don't cast me in the mold.
G. 



  ----- Original Message ----- 
  From: Karl G. Mueller 
  To: NSRCA Mailing List 
  Sent: Friday, November 09, 2007 11:03 AM
  Subject: Re: [NSRCA-discussion] wing tube sleeve hole


  Lance, 

  I have cut the holes for  the wing tube socket with a hot wire
  and two templates mounted to the work bench at the proper
  height to be on center of where the tube hole should be.
  The socket hole is cut before cutting the core itself.
  You need to make a slot in the core where the end support of the 
  tube is going to be to insert the template that is mounted to the bench.
  I then burn a small hole thru the center of the templates in the
  core with a hot piece of music wire held in a small machine vice
  that is guided along a straight edge. Then I thread the wire for the
  cutting bow thru that hole and start cutting following the two
  templates. Start with a low heat and try the fit. If the fit is too tight
  just increase the voltage a little and go around the templates again
  until you achieve the proper fit. Of course you need a variable power
  supply. Sounds more complicated than it really is. Now when you 
  cut the core, adjust your tip template to get the proper dihedral. Works
  for me.

  Karl G. Mueller
  kgamueller at rogers.com

    ----- Original Message ----- 
    From: Lance Van Nostrand 
    To: NSRCA Mailing List 
    Sent: Thursday, November 08, 2007 10:46 PM
    Subject: Re: [NSRCA-discussion] wing tube sleeve hole


    That's a hard one, Mike.  Both Terry and I use a similar method.  We had a machine shop make a jig for the cutter.  The cutter is a length of 7/8" wing tube with  a ground sharp edge, but the jig to hold it has got to be made presicely.  I used to use a seemingly accurate jig made to the plans provided in a KFactor several years ago, but my results were not good enough.  
    --Lance

      ----- Original Message ----- 
      From: Mike Miller 
      To: nsrca-discussion at lists.nsrca.org 
      Sent: Thursday, November 08, 2007 7:08 PM
      Subject: [NSRCA-discussion] wing tube sleeve hole



      http://www.mackrc.net/patternwings2/index.htm

      http://www.nextcraft.com/foamwingsandparts.html

      Terry Brox's web site on balsa skinned wings is very good and does show the drilling of the servo lead hole with a tube and by hand. 

      Their is some great information on these sites on building foam core wings. But a very important part of a plug in wing would be the wing tube sleeve hole in the core, to be straight and parallel to the desired line centered and at the right angle to set the dihedral. Is there a site that explains or shows the process of set up and drilling of this hole? If this step is not perfect looks to me like the wing is dead no matter how good the skinning process is.
      Thanks in advance

      Mike


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