Sunday, March 9, 2014

(page 15-06) Space crises postponed

By hoisting the left wing spar with all ribs attached up near the rafters I temporarily put off running out of build space and am proceeding with the right wing.  Almost all of the rivets attaching the ribs to the spar can be pulled with the pneumatic puller, which makes things proceed quite rapidly.  The closely spaced ribs near
the inboard end require the hand squeezer because of the lack of space between ribs.

I discovered that once the ribs are attached to the spar any curvature due to inadequate fluting is easily corrected, verifying my earlier decision to not be overly anal about absolute flatness in the fluting stage.

In their current configuration, the spar-rib structure is quite flimsy and I'm looking forward to attaching the skins.  Once skinned, I'm thinking I can continue to store the wings as they are now -- one on the work table and one suspended from the rafters.  The suspended wing will be turned upside down to allow use of the tie-down ring.  As noted earlier, there's a tapped hole on top but this would require drilling a hole in the skin to expose it.  As a full-fledged aero-nerd I could never bring myself to drill the hole in the top skin.

Tuesday, March 4, 2014

(page 15-05) Mistake in the build manual

Page 15-02 step 9 shows one nutplate and one W00028 doubler plate installed on a nose rib, yet page 15-05 and 15-07 refer to the nose rib with three nutplates.  After puzzling over this a bit  and studying all the
revisions, I contacted the Mothership and they confirmed that there are no longer any nose ribs with three nutplates.  These pages refer to a previous configuration and are now in error.  I'm RV-12 builder 593 and I'm sure hundreds of builders have encountered this, yet no revision has been issued.  I don't understand it.  This explains why the Homebuilt Help video didn't match what I'm doing.  It referred to the earlier configuration.  Those guys at Homebuilt Help need to keep up a bit better as well, but considering how inexpensive their product is, I forgive them.

RIP my favorite tool, the pneumatic rivet puller which came with my Isham RV-12 tool kit.  I never knew who actually made it since Isham re-branded it.  It became necessary to refill the hydraulic reservoir frequently, so I ordered a replacement from the aviation division of Harbor Freight for a mere $40.  It works great.  Can't beat the price.

It's a bit tricky figuring out which ribs go where on the spar, but the actual installation is easy.  As seen in the picture, almost all the ribs for the left wing are installed.  Space is a major problem.  Don't know the solution unless I evict the car from the garage.

Sunday, March 2, 2014

(page 15-04) Wing ribs

Attaching ribs to wing spars seemed fairly painless and straight forward until I discovered that I had somehow managed to attach the rib-attach angles to only one side of the spar.  When page 15-04 called for clecoing and then riveting nose ribs to the rib-attach angles starting at the outboard end of the spar I got that familiar sinking feeling that accompanies the realization that I had made a mistake.  Looking back at page
13-03, I saw clearly that attach angles go on both sides of the spar.  I have no idea how I missed it.  The good part is that everything that needs to be redone is completely accessible and involves pulled rivets which are much easier to drill out than squeezed rivets.  The bad part is that there are 50 rivets that must be drilled out.  Fortunately, I have acquired great skill at drilling out rivets, so it didn't take long to accomplish.

The real pressing problem is where I'm going to store the left wing  spar with ribs attached when it's time to do the right.  I put a 3/8-16 eye-bolt into the previously-drilled-and-tapped extrusion intended for the tie down and used it to hoist the right spar up to the rafters until I'm ready for it.  I'm hoping the wings can be stored in a similar fashion.