forward floor stiffener question

[alpinelakespilot2000]

7/9 forward floor stiffener question

Has anyone else had edge distance issues where the floor stiffeners are riveted to the bulkhead cover brackets? I've marked the problem hole with an arrow in the picture above. I have not trimmed my floor stiffeners at all and the holes that attach the stiffener to the firewall and F904C are both 6/32 or 7/32 from the ends of the stiffener (meaning I really have no room to move the stiffener forward or aft for the 3/32 rivets). The pilot holes in the cover bracket are 1/8 and the edge distance they would leave me with on the stiffener is about 5/32. Did I just get short stiffeners? Thanks for any thoughts.

 

[Paul Eastham]

Hi Steve,
I just went out to my plane and see that my rivets in that spot look to be about 2D center-to-edge on the stiffener -- about minimum allowable "by the book". (are you measuring center-to-edge or edge-of-hole-to-edge-of-stiffener?)

My stiffeners seem to be about the same distance from the center section as yours, though it is hard to tell from the angle of your photo. Mine end right at the beginning of the bend in the center section flange. Perhaps the pilot holes on the cover bracket were a little bit off?

At any rate, given the name of this part ("stiffener") and the other big, well-placed rivets nearby, I am having trouble seeing this as a fatal flaw. Send Van's your photo and see what they think.

Paul

 

[alpinelakespilot2000]

Thanks Paul for actually going out and measuring that! It is very helpful and I appreciate it. I haven't actually drilled the stiffener yet, only marked the stiffener through the pilot hole in the bracket. One stiffener was left with 6/32" and the other with 5/32" measured from center to edge. Maybe Van's will allow me to drill a new hole in the bracket farther forward... who knows, but thanks again.

 

[Paul Eastham]

No problem. I had another thought: are you sure you've got the right stiffeners in place, in the right directions? Each end is bent slightly differently. As I recall this was quite confusing, and it might make the difference on your edge distance.

 

[Steve]

Steve,
The aft rivet is damned near impossible to set due to clearance problems. One solution is to set it prior to riveting the bottom skin, as per Mike Shipper (sp). Another possibility would be to use a structural pop rivet.

Steve

 

[dan]

Maybe Van's will allow me to drill a new hole in the bracket farther forward... who knows, but thanks again.

Call Van's and ask them, or send your photo and comments to [email protected]. Their answer may surprise and please you.

 

[LettersFromFlyoverCountry]

I just went out and measured mine and, yeah, it's about 6/32 from the edge. It was so long ago (OK, last year) that I don't remember if I thought much about it or not. Of course the other stiffeners aren't riveted in that location, so I'm not sure hos structurally critical it is. That stiffener near that location -- through various proxies --is connected to the cover, the center cover, and the -- if you have one -- high performance fuel pump.

Do post what Van's tells you.

 

[alpinelakespilot2000]

Glad to hear I'm not the only one who had edge distance issues... sometimes I wonder if I get too uptight about these things.

Call Van's and ask them, or send your photo and comments to [email protected]. Their answer may surprise and please you.

Dan... I did send my question to support@vansaircraft last night. If I had sent it to engineering, what do you think their response would have been? Sounds like maybe you already asked that question?

Thanks to all for the replies... I'll post back what Van's response is on this.

 

[alpinelakespilot2000]

Vans' reply

Here's Van's answer to my question, worded basically as I wrote below in the original post:

"One or two rivets with less than ideal edge distance scattered
about the airframe is not a big deal. You can use the factory hole
or drill a new one, it's up to you. The parts are fine. Where edge
distance is more important is on a row of rivets.
Bruce Reynolds
[email protected] "

Hope this helps and thanks to everyone who replied.

Has anyone else had edge distance issues where the floor stiffeners are riveted to the bulkhead cover brackets? I've marked the problem hole with an arrow in the picture above. I have not trimmed my floor stiffeners at all and the holes that attach the stiffener to the firewall and F904C are both 6/32 or 7/32 from the ends of the stiffener (meaning I really have no room to move the stiffener forward or aft for the 3/32 rivets). The pilot holes in the cover bracket are 1/8 and the edge distance they would leave me with on the stiffener is about 5/32. Did I just get short stiffeners? Thanks for any thoughts.