great news on bending the "formed" steel ribs.....

[fairchild1934]

i tried hydroforming the counterbalance rib on the rudder tonight. i am shocked how easy it is. It is WWAAAAAYYYY easier than hydroforming the aluminum wing ribs. It went to about 85 degrees after just one press. A quick pass with a plastic mallet down the bend line-- and its basically ready for the fluting pliers. I think it was the fact that the soft steel isn't work hardening as the bend progresses. Like butta-----

Tim


i see bob has machine screws going in edge ways to hold the counterbalance weight.
I was thinking of adding a triangular sheet metal gusset in that corner-- and then bolt the lead slab to the gusset. Anyone see any hidden problems with that ?
I am not crazy about threading bolts into lead----- and expecting it to stay put long term.....

[fairchild1934]

the formed rib looks like it will be great now. But the plans dont seem to show any "rollover " of the edges on the curved steel ribs. What stops the fibric from being cut at those sharp edges ?

[SpruceForest]

Congrats on the success at forming the stab ribs... building from plan reinforces the idea that most challenges are overcome in the doing. Hiring it done may eliminate the challenge, but also strips away the satisfaction that comes overcoming that obstacle to progress.

Re: chafe - same problems on the aileron and flaps, or other places where a sharp edge under the fabric makes both sanding and covering movement subject to wear, etc. A good deburring of the edges and use of the recommended anti-chafe tape per your covering system's specifications should address things. FWIW, Polyfiber anti-chafe tape is 1" wide, so it will give a bit of drape over the critical edge on our typically narrower control surface rib flanges. -1B is the general reference, but the covering system documentation should have explicit instructions on the task.

[Bcone1381]

Notes on my Plans. You can see the Patrol rib has the raw edge formed to avoid contact with the covering.


Screenshot 2024-07-05 at 2.21.27 PM.png

[fairchild1934]

Yes Brooks----- the flat steel ribs do but no mention of the curved ones. Not even sure how it could be done since the curved ribs are curved and they have fluits. They make a 1 inch wide scotchbrite wheel that goes on a bench grinder made for deburring parts. Might try hitting the edge with that too.
The only other thing I can think of is to bend the flange to like---- just a bit past 90 degrees. so that edge is just below the fabric by 1/32...