Forming 4130 ribs

[lostman 198]

It seems like about two years ago I saw a video on here about forming 4130 ribs for the tail surfaced. I can't seem to find it. Of course since there are a myriad of words that can be used to search it makes it difficult.

Does anyone remember seeing this?

How have you built them? I am working on my Sonerai and need to form two tapered 4130 .035 ribs but can't figure out a good way to do it. I wish I had a sheet metal brake but don't. 

Any ideas or suggestions are welcome.

Kenneth

[EDMO 1078]

It seems like about two years ago I saw a video on here about forming 4130 ribs for the tail surfaced. I can't seem to find it. Of course since there are a myriad of words that can be used to search it makes it difficult.

Does anyone remember seeing this?

How have you built them? I am working on my Sonerai and need to form two tapered 4130 .035 ribs but can't figure out a good way to do it. I wish I had a sheet metal brake but don't. 

Any ideas or suggestions are welcome.

Kenneth

Without a picture I have to just guess, but mild steel for a short run is as good as 4130 - Can you take some small angle stock and form the top and bottom and weld them together at each end?    Maybe make a form and heat and bend them if you need a curve, and cut some small notches if needed?   I have several formed aluminum tapered ribs for my flaps and ailerons, but I am going to use aluminum angle stock to make more.  EDMO

Edited 21 Feb 2016 by EDMO

[lostman 198]

Ed, I'm sure that mild would work but the one is over a 20" span, plus I have the 4130 that it calls for. It's tapered from 7/8" round tube on the post to 7/16" on the front of the vertical stabilizer leading edge. It is basically just a big U shape but has to fit the mentioned dimensions so it has a fairly tight tolerance for measurements. I had thought about making one from Aluminum but then I'd still have to attach it to the 4130 tubing. I have thought about making two 90 degree angles and then overlapping and welding them together too but hate to have those two ribs kind of cobbled together as it were. These ribs get either stitched or you rivet the fabric to them after shrinking. 

[EDMO 1078]

Lostman,   Still guessing, but could you put the 7/8 tube lengthwise between two sufficiently strong bars/flat stock/wood and put a clamp on each end to squeeze the tube on a taper to one end to the dimensions you need - it would be round on one end and oval on the other - maybe one end in a press?  Just hoping to give you some ideas, and hoping for success.

EDMO

Edited 21 Feb 2016 by EDMO

[lostman 198]

If I'm following you correctly that won't work. The rib sits at a tangent to the 7/8" tube and needs to have square angles. It is only .032 4130 plate. I also don't have any 7/8". 

Are you actually talking about squaring off a piece of tubing to make the rib? Still not sure I'm following. I'll see if I can get a picture up later. 

[EDMO 1078]

If I'm following you correctly that won't work. The rib sits at a tangent to the 7/8" tube and needs to have square angles. It is only .032 4130 plate. I also don't have any 7/8". 

Are you actually talking about squaring off a piece of tubing to make the rib? Still not sure I'm following. I'll see if I can get a picture up later. 

I thought you had 7/8 round tubing, and I was talking about flattening it on a taper until it was oval and the end width you needed.  I have a brake, and if you were still down here I would try to help make them.  Sorry,  EDMO

Edited 21 Feb 2016 by EDMO

[lostman 198]

Now I get what you're saying. If I had the tubing to use for that, it's a good idea.