Spars

[Vince Carucci]

I need some guidance on the spar build. After watching the video and reviewing the drawings, I've made observations/drawn some conclusions. 

• It seems the blocks and wedges probably get positioned at the rib attachment points (10 places)
• Then the spar gets assembled and locked in place. 
• Then I think the .125 plywood gets glued to the spar frame. 

How does the plywood get secured to the spar frame while the glue is drying? Do we use staples here too? Is there some other clamping method? Finally, is there anything else I should know about before starting this stage of the build?

[Bob S.]

Vince,

I stapled the 1/8" ply to the spruce frame.. the same way the ply gussets are stapled to the spruce ribs... Use enough that the ply does not buckle or leave gaps between the caps and the ply. Pull staples after glue sets, before releasing from the wedge clamps... Try not to gouge the ply too badly when removing staples. You might get some dress-making ribbon and staple over, makes pulling easier. Pull the ribbon up and pull remaining staple with plyers..

[ParQld]

Hi Vince, I am building the DE and here is a link to some images in my G+ Gallery if you find them useful. I just fell for the Gotcha with the spar doublers. I attached them too soon on the rear spars and now cant slide the ribs over the spars. I am working on a fix now. Just watch that one.

DE-69 - Build images

I positioned the wedge blocks inline with the intercostals (these are invaluable)
The Spar frame is built and then the webs are applied. (dont apply the doublers at the back of each spar at this point or you will regret it like me)
I used small water bottles to hold the ply webs down whilst the epoxy was drying.

hope that helps

cheers Paul

[Vince Carucci]

Bob/Paul,

Thanks for the answers. That was just what I was looking for. I might look into the dress making ribbon idea if it helps remove the staples quicker. And Paul, those were some great pics, very helpful. Sorry to hear about the spar doublers (2 steps forward - 1 step back). It's reasons like this that this forum is a gold mine. 

Vince

[docmatt]

I used old car batteries and buckets of scrap metal to hold the ply during gluing.  If you glue the ply doublers before putting the ribs on, find somebody with a planer you can borrow.  It makes it pretty easy to remove the ply.

[ParQld]

Doc, when you say planer do you mean a hand plane or electric.  Someone else advised using a belt sander but i am concerned about damaging the spar caps if this was to violent.

Sure would save a heck of a lot of mucking around though . Even if I just removed the doublers at the wing attach point. Hell i would even buy a planer! That would reduce having to modify the ribs from 18 to 4

interested in any comments about this

cheers Paul

[Vince Carucci]

Paul,

Even after you warned about gluing material to the rear spar before ribs are installed, I still managed to repeat the error. The good news is it's a small piece of plywood at the wing root. So I took a small hand plane set up for a VERY shallow bite and began removing the layers of the plywood. I stopped with the hand plane when I could just see the spruce showing through.  I finished removing wood and glue with a heavy grit sandpaper. I managed to get back to the spare frame with almost no loss of original dimension and very little reworking damage.

Vin

[docmatt]

I used an electric planer.  You can set the thickness very precisely.  You shouldn't need to buy one.  Most guys who work with rough cut lumber will have one.  Maybe check a cabinet maker.  I used rough cut spruce for all of my wood except rib stock.  I had a friend with a nice wood shop help me cut and plane everything to correct dimentions.  I saved a bundle of $$.

A couple good hand planes are indispensible for making the spar cap tapers and removing glue blobs from the work table and the wings. Also good for removing varnish that sneaks onto surfaces you want to glue.