Radius nose rib flanges

[BrianP]

Still at the start of our build. Page 6-3 asks you to radius the corners at the forward end of the nose rib flanges. Section 5 is not overly clear on how to do this. Is there a special tool that can be used to curve the flanges? Do you wrap the skin around it and look for pressure points? And how do you debur the edge in the small gap between the flanges?

Thanks!

 

[kirkbauer]

1) I used my grinder to radius the nose so that it is more rounded. It's hard to know how much so I'll let others comment on that.
2) I use these in my Dremmel tool for all of the hard-to-access deburring. I go through a ton so I'd suggest a large pack: https://www.amazon.com/gp/product/B0B42K9YQX

 

[skelrad]

You don't need to take much material off - just look down the flange and you'll see where portions at the nose stick up beyond the bounds of a smooth curve (by the bent portion mostly). This is just a function of flat material that is tangent to a circle inherently having its edges stick beyond that circular boundary. I used my scotchbrite wheel to round them off. The sander was too aggressive given how little material gets removed. It should literally just take a few seconds for each rib.

In terms of deburring the notches, I just fold some sand paper up and run it through each notch a few times. Just enough to knock off any sharp edges - they are usually just on one side of the material due to the lip created during the cutting of the part.

 

[rocketman1988]

I had to take a substantial amount off. You will only get one chance to know if you removed enough; the pimple after riveting will let you know.

Scotchbrite wheel works great.

I also think most people debur too much.

 

[BrianP]

I had to take a substantial amount off. You will only get one chance to know if you removed enough; the pimple after riveting will let you know.

Scotchbrite wheel works great.

I also think most people debur too much.

When I gently place them inside the skin, it seems like there will be quite a significant amount of stretch before the rivet holes will align. I’m assuming that pimple generally happens in front of the very first rivet?

 

[rocketman1988]

When I gently place them inside the skin, it seems like there will be quite a significant amount of stretch before the rivet holes will align. I’m assuming that pimple generally happens in front of the very first rivet?

Yep

 

[BrianP]

Yep

How thin can you grind the flange before there is a structural strength issue? I feel like if I taper the front anymore that will be a concern.

 

[PilotjohnS]

I would not worry about taking too much off. The leading edge radius in the skin makes it really strong. One really doesn't get much additional strength from the leading edge rib being forced into the skin. Any contact between the rib and the leading edge radius of the skin in front of the first rivet doesn't add any additional strength, so I have been told by a aerospace structure expert.

I re radiuses my nose ribs to avoid the stretch and pimples in the skin. Worked out well.