Scoop-Making

[Chris Theron]

Anybody have a web-address for details (dimensions/calculations) of these NACA (the real thing) ducts?

Thanks

Chris Theron
  ----- Original Message ----- 
  From: Wayne Powell 
  To: discussion at nsrca.org 
  Sent: Thursday, July 03, 2003 3:17 AM
  Subject: RE: Scoop-Making


  Just for clarification, the NACA ducts are the ones that were previously made by PTX; Bolly makes no such beast.  Precision bought the molds from Peter Thannhauser.  I've got them in my Piorun Medal in the belly pan and on the nose - should be able to see how well they work this fall.  If nothing else they really look cool!

  Wayne Powell
  Bolly Props North America
  http://www.BollyProps.com
  1-877-WEFLYRC  
    -----Original Message-----
    From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Ron Van Putte
    Sent: July 2, 2003 10:00 AM
    To: discussion at nsrca.org
    Subject: Re: Scoop-Making


    John Ferrell described a technique for obtaining air inlets/scoops.  It looks like fun for people who like new and different adventures in modelling.  However, I prefer my technique:  contact Mike or Maureen Dunphy at Precision Aero Composites [phone:(662) 462 5480, e-mail mdunphy at avsia.com or internet: www.precisionaerocomposites.com] and order a set (3) of their Bolly NACA inlets.  I plan to use a set on Tony Stillman's new Panacea design, which Mike and Maureen will market and will also be using a pair of the Bolly F3A carbon/kevlar wheel pants, which they also sell. 

    Ron Van Putte


    John Ferrell wrote:

      If you would like to dabble a bit in a small glass project scoops are an ideal subject. Just about any epoxy will work well. Check out the spoons available in housewares (avoid the kitchen drawers unless you are batchelor or want to be one). You can make the mold using a carved up spoon, play dough, paper mache,wood scraps, balsa or whatver your imagination will provide.  I like to hold the stuff together with hot melt glue.Avoid polyester resin because it will probably get hot enough to melt your mold. If you don't happen to have any suitable glass fabric, scrap from the rag bag, or a handkerchief will do...these are not structural parts. Use some kind of wax for mold release, I like paste floor wax like I use on the table saw. Try to avoid a wax with silicon, it will be very hard to paint otherwise. After waxing, spray with with hair spray.

      If your model is not destroyed taking it out of the mold, you spent too much time on it!

      When you do the lay up, wax the mold at least 3 times, polishing each time. Spray liberally with hair spray. avoid runs, they will require filling in the part. When you start the lay up in the mold first paint it with a thin coat of the epoxy. That will assure a passible finish. It takes longer, but small scraps of cloth are easier to fit in place without wrinkles. try to make the fabric cuts at 45 degrees to the threads, it will conform to the curves easier. 

      You don't have much to lose with this size project!

      Fitting the scoops to the fuse:
      Tape sandpaper to the fuse (smooth side down).
      Rub part carefully against the location to be fitted. 
      John Ferrell 
      6241 Phillippi Rd
      Julian NC 27283
      Phone: (336)685-9606  
      johnferrell at earthlink.net
      Dixie Competition Products
      NSRCA 479 AMA 4190  W8CCW
      "My Competition is Not My Enemy"

        ----- Original Message ----- 
        From: Bob Pastorello 
        To: NSRCAMail 
        Sent: Wednesday, July 02, 2003 7:22 AM
        Subject: Scoop-Making


        Decided I want to use a scoop on my latest for crankcase/bearing cooling.  I know where to locate it on the cowl, but have no idea of shape, angle, if any "ducting" is needed.  It looks like the scoops out there just direct air based on their shape alone...without ducting.
            Anyone have any suggestions/ideas on this?
            What to make the scoop out of?
            And how to determine what size is "right" ?

        Any insights much appreciated....thanks in advance.

        Bob Pastorello, Oklahoma
        NSRCA 199, IMAC 1320, AMA 46373
        rcaerobob at cox.net
        www.rcaerobats.net



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