Arf Nobler Repair

For those of you who like to see a little into the guts of the Top Flite Nobler Arf, here are some photo's of the recent repair I made. What happened is that the engine quit on me at about ~45 degrees going up (and slow), and I was unable to run fast enough to regain control. The impact was almost vertical on the nose, but fortunately the power was off. Damage was that the fuse broke in half just between the canopy and the trailing edge, and the center section of the leading edge of the wing tore out. I had built mine as a take-apart, so the belly pan was only RTV'd onto the lower wing.

By the way, the crash was my fault, the engine was running waaaay to rich and slow, so I may have run low on fuel and uncovered the clunk. I was running a Sullivan plastic klunk tank, which requires a large offset bias on the uniflow in order to line up with the spraybar. As you will see, I decided to install a Brodak medium wedge uniflow tank. It requires one to cut out the firewall to the engine bearers, since it protrudes out of the tank compartment by ~1/8 inch or so.

LAST EDITED ON Sep-02-03 AT 05:00 PM (CDT)
 
a little text with the photo's.

1) Just showing the crack. On the inside I put in some doublers and a tripler to tie the front end (which has a lite ply structure) with the tail section.

2&3). The original leading edge was quite thin. It did have a reinforcement wedge which tied the two wing leading edges together. However the dowel hole compromised this a lot. Of course the original was tied into the center sheeting. I note that I hadn't noticed any problem with the structure during my previous flying. At this point I simply decided it would be a little easier to just carve a new center section which would support the dowel better (remember this is all the support I have. I also added the square ply piece which is glued to the stock balsa block. I used Polyurethane glue to fill any gaps. I tried to get as tight a fit as possible. You can also see the 1/4 inch diameter aluminum rod that I used as a replacement for the original wooded dowel---I didn't have a piece of 1/4 inch wood dowel!

4) Looking into the tank compartment, You can see the wing dowel (and its reflection off the tank) resting in the ply support former.

5)View from the front of the Brodak 40 and tank. After putting this back together, I covered the firewall opening with some flexible foam to seal off the tank. I just poked some holes in the foam fro the tank tubes to fit through.

You can see a picture of my repaired Nobler which I flew this weekend at the TreeTown contest (see Treetown link). Mine was the one with the Navy Sticker. (The other Nobler was Chuck Zellermeyer's. It doesn't look perfect, but seems to fly as well as before, (even if I am not!).