Wings #9

Had a very productive week in the hangar - got some of the little, pesky, time-consuming things done.  To start with, I finished the control horns for all 4 ailerons.

Original control horn and backer plate

The photo to the right shows an original and the backing plate.  Like many of the fittings, it's made in multiple pieces.  Some are single-wall, some double to keep the weight a minimum, yet strengthen certain areas.  You can also see an area I ground away to measure wall thicknesses.  The base is .100", the main body is .050" bent into an airfoil shape and edge-welded on the trailing edge.  The top is a .050" U-channel that is edge-welded in to strengthen the area where the aileron cable attaches.  The backer on the other side is .050".

Finished control horns and backers

Also completed was the trailing edge on the wing.  Fortunately, this wing uses a typical bent aluminum trailing edge that is common on many, more modern aircraft.  Before attaching it, I did install a strip of spruce along the trailing edge of all the ribs.  This will help keep the aluminum edge straight and prevent it from bowing as the fabric is shrunk.  Prior to attaching, I went to considerable effort to make sure the trailing edge of the wing lined up exactly with the trailing edge of the aileron.

Trailing edge installed

Lots of planing!

In last weeks post, I showed the leading edge glued on.  It just had to be shaped into a bull-nose profile.  Came out great, but did a lot of planing - I should have trimmed some of it off first with the table saw, would have made for less work!  Oh well, I'll know better next time.  To make sure the final profile was exact down the entire length of the wing, I made a sanding block that had the correct profile.

Sanding block to make sure final shape is correct

Finished leading edge

Tip bow template

Finally, I got a good start on the tip bow.  Some aircraft of this era use a laminated wood tip bow.  Fortunately, the LP-3 used a 3/4" tubular steel one - way easier to make!  I wanted to make sure there was a nice transition from the tip bow on the aileron to the leading edge of the wing.  

I started with a template made from aluminum tubing.  Once I was satisfied with the shape,  I used a conduit bender to bend the 3/4" 4130 tubing.  It worked good, just had to go slow and only bend a little at a time.

Tip bow being bent on conduit bender

 Once the fit looked good, I welded on attachment brackets and drilled mounting holes thru the spars and nose rib.  I stewed over making this for a long time, but in the end it was actually quite easy.

Checking final fit and alignment

Attachment brackets added

Final fit up with all attachments in place

I got the tip bow painted and will have it installed this week.  What's left???  Some misc. bracing, final tramming and final application of spar varnish.  Very close, although not much will be happening the next couple of weeks.  Have several aircraft coming in the shop for annuals - have to replenish a very depleted restoration fund!!