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Posted by Mucksmear | Jan 15, 2021 @ 10:26 PM | 12,299 Views
Background: In the early 90's I started my first 1/4 scale build, an A&A Industries Citabria by Bud Nosen. It took me about 15 years on and off to just frame the left and right sides of the fuselage. When my kids were born, I picked up the pace and managed to finish her by 2007. After a successful test flight and just a few flying sessios, I mistimed a flight, ran out of battery and got too low to dive for speed and too slow to flare, so it mushed into the rough terrain slightly nose down. There was significant damage to the LG mounting plate and the fuselage bottom in that area. The motor mount also came loose and there was some minor wing strut damage too. Then we lost our field (BARCS) and the airframe just sat in the shop for the next 13 years until now.

The original build threads are here:

The LG was mounted with steel screws - if I had used nylon bolts, the damage would probably have been constrained to the area below the LG plate instead of including the longerons and some of the fuselage sides. The LG plate has been re-attached and the bottom longerons on each side have been re-spliced with new stock. You can also see the irregular patch on the fuselage side, surrounding the strut attachement slot. This whole area was crunched on both sides of the fuse. The original fuse bottom covered the LG in a continuous slab. I had to remove one wheel to slide the LG out. This time I'm making the whole section a hatch so the LG drop straight in.

I'll add new progress entries in the comments below
Posted by Mucksmear | Jan 12, 2021 @ 01:03 AM | 6,919 Views
Over the next few days, I'll be posting the build log for my 1/4 scale Bud Nosen Citabria from an A & A Industries kit. This build log was originally created back in 2007 and was documented on my website but several years ago I removed those pages to make room for other content, so now it will live here. Since then, the Citabria has flown several times until its last flight that same year which ended in an unplanned off-field "landing" with moderate damage. More on this towards the end of the build log. This build log will be followed by a repair log that is finally happening now, 14 years later...

This A&A Industries kit was discount "lumber yard" of what I would call wood scrap seconds. You've all heard of die-smashed wood, and this kit had plenty of that. Most of the ribs looked like they were cut out with an over-grown fingernail. But that's not the worst of it. All the 3/32" ply pieces were die cut half way through on the back with some other pattern, so all of that ply was DOA. I ended up replacing at least 50% of the kit wood if not more.

The basic fuselage structure is a straight forward build. Left and right fuselage sides are framed up and then brought together with the cabin bulkhead, formers and cross members. The structure becomes very rigid once the tail end is brought together and the firewall is added. The bulk of the truss fuselage is 1/4" balsa stick, but in hindsight, I should have replaced the fuselage longerons with 1/4" x 1/4" spruce. I did however add 1/32" ply gussets to tie the vertical and diagonal sticks to the longerons.

The kit manufacturer provided two pieces of 3/32" cheap door-skin plywood (to be laminated together) for the firewall. This was replaced with a single piece of 1/4" birch aircraft plywood (5-ply).

Unfortunately the first few photos are pretty low rez from the original website archive but I managed to find a few higher rez backups on my local drive. These appear with the rest of the progress in the comments below.
Posted by Mucksmear | Aug 29, 2007 @ 01:13 AM | 6,365 Views
Thought I'd share some pix from a recent visit to the USAF museum at Wright Patterson AFB in Dayton, OH. This place is huge!

For those who have never visited, I would agree with others who have said this museum surpasses the Smithsonian National Air & Space Museum in DC, although one must keep in mind that the USAF museum focuses specifically on US military aviation while the National Air & Space Museum is broader in scope.