Fuselage Lower Longeron Doubler Flange

Hi all,

A sanity check if possible!

I am at the point of drilling the doublers for the lower fuselage longerons. As far as my understanding of the plans goes - when separating the 2 lower doublers from each other, there is a note on Page 28-07 (Figure 2) which says "flanges point up".

My understanding it that this refers to the position of the flanges **when marking the parts left and right** - NOT how they are installed?

It seems to me the flange could be installed in either direction? (down seems like it would make setting the lower skin rivets very very hard). However, i think down is correct.

Steve's site shows them flanges down:
https://vansrv14project.uk/2019/10/10/29-06-to-07-longerons/

This site also shows them flanges down:
https://myrv14.blogspot.com/2019/10/fuselage-fwdmid-side-structure-part-x.html

With the comment: "Van's confirmed that the orientation as above was correct in photo 3."


but VJ's site shows them flanges up:
https://myrv14.blogspot.com/2019/10/fuselage-fwdmid-side-structure-part-x.html

Smash also has them flanges up:
https://www.smashsrv-14build.com/search/label/Section 29


Did most people go with flanges down?

Down. Tracking through the pictures, it is down. Up would seem to catch dirt and water.

If you look at figure 3, page 29-07 you can’t see the flange in the drawing which would mean it is intended to go down. The rivets aren’t that bad if you have one of these.
https://www.speedwaymotors.com/Rivet-Bucking-Bar-Tool-2-Pounds-Heel-And-Toe,468388.html