build question rib flanges

[bobnoffs]

hi all,
i will soon be ready to skin my vert. stab. i have fluted the flanges on all of the pieces so they lay flat. probably i am asking the obvious but should i bend the flanges the few degrees it takes to make them perpendicular to their webs? if i don't it seems it will be difficult to have them press tightly to the skin as i rivit them.
bob noffs
n.wi.

 

[JanRV6UK]

Always good to have the flange laying snugly against the skin

 

[John-G]

Use caution

Bob ? as previously mentioned, always a good idea to have the flanges sit flush to the skins.

That said, a word of caution ? not all the flanges in the RV-12 kit are 90 degrees, so don?t get into the habit of making everything 90 degrees without looking closely at the application for the part.

Case in point, the flanges on the tail cone?s bulkhead ribs are not 90 degrees to the skin because of the tail cone?s taper ? the tail cone gets smaller from the baggage compartment bulkhead going aft towards the aft bulkhead so the flanges are at a slight angle to accommodate that taper.

Initially, I blindly started squaring one of the tail cone bulkhead?s flanges and after tweaking the third flange and realizing each flange was ?out of square? approximately the exact same amount, it set off red flags! Fortunately, I caught the error of my ways very early on.

So far, I?ve found the factory bent components in the RV-12 kit are, by in large, amazingly around the proper angle and typically only require minor tweaking, if any ? a testament to Van?s production quality.

 

[XOverZero]

Short answer is no.

Second what John-G said. The VS is tapered, therefore the rib flanges are not and should not be perpendicular to the webs, and I also am continually noticing (to my admiration and approval) how precisely the flanges are bent to match the angles of their mating skins.

There is one note you should pay attention to, though - the first of several similar ones sprinkled throughout the build. Step 1 of Page 06-07 1 it says, "...check that the narrow end of the VS-1202 Front Spar, VS-1205 Tip Rib, and VS-1206 Mid Rib will not deform the leading edge of the main skin, radius the narrow ends of the ribs..."

I've found that each time the instructions make a suggestion about possibly needing to adjust the fitment, it is actually more than a mere suggestion. If they give you a note saying something might deform slightly, figure that it will, and follow the suggestion to remediate it before proceeding.

Happy building!

 

[bobnoffs]

thanks guys. right after i hit send it hit me that maybe 90 deg. wouldn't always be right.
bob noffs

 

[rvbuilder2002]

hi all,
i have fluted the flanges on all of the pieces so they lay flat.

To add a clarification to the process... in instances where you do need to adjust the flange angles, that should be done first, before doing any fluting.

The forming of the flanges, is what causes the need for fluting in the first place. If you adjust the flanges after fluting, the parts will no longer be straight and will need to be fluted again.