Scale Nelitz 1/3 scale Cub build

[dhal22]

I have found it easier to put the Champ on the nose while accessing the interior. The batteries and switching under the front seat.
I enjoyed following Merlyn's builds as well. There is a fellow over on RCG rebuilding his Starship, don't know if you had seen it? He is taking pounds out and different airfoil.

Correct on the starship rebuild, amazing the weight difference. I've followed that build since day 1.

 

[dhal22]

Thinking that this wing lock idea will be fine for the front spar. I'll just leave the scale bracket unused inside the cabin.

Drilled and countersunk before I cut the bevel. This is just pine wood, a trial piece. It looks like I need about a 2" bolt so this is on hold until McMaster Carr delivers (next day here in Atlanta).

I clamped the pre drilled block, then drilled through the block.

 

[dhal22]

First and second rib infill tonight. I put some support under to give me an easy landing spot and I didn't have to worry about precise cutting.

 

[dhal22]

Added some hardwood end caps before i infill between the cabin ribs.

 

[dhal22]

Filling in the cabin/ fuse ribs tonight. This is thicker balsa so straight gluing to ribs.

 

[dhal22]

Upper front wing/ cabin area just free floats, nothing tied to the framework at all. I'm to finding some online Cub photos indicating some cross brace structural support. Once I confirm this, game on as I'm tired of fretting over this problem.

 

[TonyHallo]

Look here. The structure is formed by the center support, wing spar, and lift struts, the rest of the structure in the cabin area is window dressing.

 

[dhal22]

Excellent, then I'm on the right path. Nothing is shown on the plans but I knew something wasn't right.

 

[TonyHallo]

I just did some calculations based on 1220 pound gross weight full scale Cub, the lift struts are carrying 1080 pounds of the lift force while the center bolts are carrying the remaining 160 pounds of lift. Of course this is at level flight. There is also a compressive force on each spar of about 500 pounds, this force cancels in level flight. The drag forces will tend to decrease the compressive forces somewhat. This is why the Balsa USA Cub can fly with 2 - 5/16" wood dowels at the root, most of the forces are in the struts. Many what to put a wing tube in but the cabin structure is not there to carry the load without the lift struts.

 

[dhal22]

Mostly the entire upper cabin/ wing area is (currently) only supported by 2 window pillars. Side to side sway is almost zero but still there. The little cross braces will be plenty.