[NSRCA-discussion] Sheeting built up wings...old school!

Tue Dec 15 05:14:35 AKST 2020

On Facebook Henry Piorum has how he does it . This the way I do them and
really is the only way to guarantee the wing is straight .

https://m.facebook.com/story.php?story_fbid=10159237472893627&id=614543626

Matt

On Tue, Dec 15, 2020, 8:08 AM Stuart Chale via NSRCA-discussion <
nsrca-discussion at lists.nsrca.org> wrote:

> If the skeleton can twist then I would think it would be very difficult to
> get it straight.  Once the first skin is glued in place any twist is locked
> in.  A properly designed jig is the only way to be sure it stays straight.
>
> One other option is to cut a foam core.  The outer shucks can be a very
> good jig.
>
> Sent from my iPad
>
> On Dec 15, 2020, at 9:01 AM, Richard Lewis via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
>  Thanks Andre,Mark,Don, etc...
>
> Y’all gave given me a good idea of how to proceed.  The jig Andre
> describes seems like a good idea.  I’ll have to mock that up and see how it
> looks.
>
> I was considering doing the first skin just using the table as the flat
> surface.  Laying the skin good side down and pressing the TE down against
> it and CA’ing the TE to the skin, then rolling the wing forward onto the
> spar and tacking it there with CA and then rolling it up onto the false LE
> and gluing there.  The second skin, I could then do with Andre’s jig
> suggestion maybe?
>
> I did the stab this way when I built it, but I was able to attach the
> second skin with just the pressure of my hand and medium CA on the
> skeleton.
>
> Richard
> Sent from my mobile device.
>
> On Dec 14, 2020, at 8:43 PM, Andre Bouchard via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
> 
> Richard,
>
> I have built a lot of MK kits.  If the 40-size is built like the 60-size
> models the sheeting will go over the trailing edge stock and a false
> leading edge, so those pieces should already be part of your skeleton.  You
> are going to need a jig.  You can make a jig out of 1”-2” wide x 1/4”-3/8”
> thick x 36” hard balsa sheets.  Glue the sheets width dimension vertical on
> a piece of glass or melamine in the shape of the wing planform.  You will
> need two jigs.  Draw a center-line on the false leading edge and trailing
> edge.  Pin the wing skeleton to the “jig” such that the center-lines are at
> the top edge of the balsa sheets that constitute the jig.  This keeps
> everything at the same height off of the work table (ie straight). There
> will be enough false LE and TE material below the top of the balsa sheets
> to pin to (pins horizontal). With enough pins you can put sufficient weight
> on the wing skin to hold it in place while the glue drys.  Do top or bottom
> sheeting on both wing halves then “flip” them in the jigs for the opposite
> side sheeting.
>
> For additional support of the wing you could cut a tapered piece of wood
> than sits between your table and the spar, but note that the thickness of
> that piece will have to be adjusted once the sheeting is put on.  I do not
> think this is needed for the size of wing you are building.
>
> As Don noted, sanding the wing skins should be done before putting them on
> the skeleton. Basically, finish ready on one side.  Make sure you keep
> track of which side is the finished side when gluing the skins on.
>
> With the skeleton on the jig you should check the ribs with a straight
> edge along multiple chord lines.  Lightly, carefully sand if needed
> (likely) with a sanding bar longer than the wing panel.  You do not want to
> change the airfoil shape, but you want to remove the high spots.  If you
> find a low spot, glue a soft strip of balsa on and sand to the shape of the
> other ribs.  Put masking tape on the root and tip ribs to preserve the
> airfoil shape of the other ribs while sanding to level them.
>
> As Mark noted, without a jig that supports the sheeting at each rib
> station (eg, Allure/Alchemy builders kits, FlightHobby kits, Revo built-up
> wings), I would not use Poly glue.  I suggest also using Titebond, put on
> with a hypodermic needle.  You will not need a lot of weight with an
> non-expandable glue.  Small pins and/or Green 3M auto tape can be used to
> help hold the sheeting at the LE and TE.
>
> Regards,
>
> Andre
>
> On Dec 14, 2020, at 10:50 AM, Atwood, Mark via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
> Regarding weighing down the top side, I’ve had very good luck using Lead
> Shot.   I double bag it in Large Ziplocks (trust me on the double bag… if
> one splits, it’s a DISASTER.)  I typically have about 10-15# in each bag
> and probably use upward of 100lbs when all is done.   It forms to fit the
> curve of the wing and holds the sheeting down nicely especially if you’re
> using an expanding glue like Gorilla.    If you don’t have a form, I’d
> probably not use Gorilla for that reason and stick with titebond.    A good
> piece of dense memory foam will support the underside.   Avoiding twists
> without building a jig though is pretty difficult and will depend a lot on
> how you secured the first side.
>
> -M
> *MARK **ATWOOD*
> o.  (440) 229-2502
> c.  (216) 316-2489
> e.  atwoodm at paragon-inc.com
>
> *Paragon Consulting, Inc.*
> 5900 Landerbrook Drive, Suite 205, Cleveland Ohio, 44124
> www.paragon-inc.com
>
> <http://www.paragon-inc.com/>
> *Powering The Digital Experience*
>
> On Dec 14, 2020, at 9:31 AM, Don Ramsey via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
> CAUTION: Message originated from outside of Paragon. Use caution regarding
> any links, attachments, credential and financial requests.
>
>
> Richard,
> Maybe my last post was a little simplistic.  Here's more detail:
> 1.  Glue up panels that fit the skeleton.
> 2.  Sand the panels so at least the outside of each panel is smooth.  Do
> this before gluing the panel to the skeleton because the skeleton does not
> provide underlying support to support sanding as well as a solid structure.
> 3.  Glue the first side with CA or your choice of glue.  Wait for glue to
> dry.
> 4.  Glue the second side with a slow drying glue (in your case maybe poly
> glue) so you can fit the side easily. Weight the side to keep it the entire
> structure straight.
> 5.  Add the remaining components, LE, TE, root, tip, etc.
> 6.  That's it.
>
> Don
>
> -----Original Message-----
> From: NSRCA-discussion [mailto:nsrca-discussion-bounces at lists.nsrca.org
> <nsrca-discussion-bounces at lists.nsrca.org>] On Behalf Of Richard Lewis
> via NSRCA-discussion
> Sent: Sunday, December 13, 2020 9:20 PM
> To: General pattern discussion
> Subject: [NSRCA-discussion] Sheeting built up wings...old school!
>
> Alright, let’s see if this list is still alive!!
>
> I’m building a classic 40 sized MK kit.  The wings are fully sheeted.
> There are no construction aids such as tabs, cradles, jigs, etc. for the
> wing construction.  I’ve got the wing skeleton framed up and ready to
> sheet.  The wing is tapered thickness and the top is flat span wise giving
> the wing a slight dihedral.
>
> So the question for the builders is...What’s the best method/trick to
> sheeting a built up , fully sheeted wing structure?
>
> Thanks in advance!
>
> Richard Lewis
> Sent from my mobile device.
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