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RV3 W-309 Vs W-339 Main Ribs Issue

RV3Kev

Active Member
Dear Guys

I have noticed that the three outermost main ribs (W-309) have a reduce overlap on the flanges between the bottom main rib and the rear spar when compared to the other main ribs (W-339). See attached photos. This may make it very difficult to achieve the required ED when riveting the skins on to the combined rear spar/Rib flange.

The outer ribs (W-309) have to be fractionally longer due the 0.125 inch W-330C doubler plate that ends at about station 80 . It seems that the additional length was achieved by making the rear of the main ribs a little longer but the bottom flange length was not increased. See photo below.

To myself, the W- 309 ribs should be longer at the leading edge and the trailing edge identical to the W-339 ribs.

I have brought this to the attention of Vans and am expecting a reply next week.

Thoughts any one?


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https://www.flickr.com/photos/157411418@N02/31770926117/in/dateposted-public/


https://www.flickr.com/photos/157411418@N02/32837493278/in/dateposted-public/
 
Same problem on mine. I tried to keep the rivet holes closer to the bends, but let the edge distance relax slightly where necessary.

The bigger problem and more worrisome for me, was the top and bottom flanges where they overlapped the spar flanges, as in one of your other photos in that series:

Overlap.jpg


I attempted to center the rivet hole in the overlap, but tried to give more importance to spar flange edge distance than the flange's edge distance.

Dave
 
Yes, the ED for the overlap on the bottom rib flange and the bottom spar flange is the issue. The outer ribs three ribs , it seems impossible with the way the bottom flange has been made.

The ED for the main rib rear flange bottom rivet to the rear spar bottom flange is ok, The plans call for the bottom rivet to be 1/4? from the bottom of the rear flange but this seemed wrong to me as it doesn?t allow for the radius on the bottom rear spar flange , so l increased it to achieve the required ED.



Kevin
 
Vans Reply

Dear Guys

Got a reply from Eric at Vans who recommends installing a doubler plate and provided some details. So that how I will proceed.

Kevin
 
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