Drilling HS spar to longeron

[mcencula]

It's come time to mount the HS to the fuselage, but locating the hole which bolts the forward spar to the longeron looked tricky due to the fact that the 5/16 longeron edge distance is critical, yet the longeron is hidden beneath the aft deck. Since I wasn't comfortable with just measuring twice (or three times) and drilling, I decided to make a jig to (hopefully) help keep me from making a mess out of this process. Since a picture is worth a thousand words, here's a picture (with words included .

The angle from which the photo was taken makes it look like the hole is too far outboard, but that's just an optical illusion.

If anyone wants to borrow this thing after I'm done with it, let me know.

P.S. No making fun of my awful primer job!

 

[Jamie Aust]

Thats a great Jig !

I just used lines to mark the longeron edge and the middle of the rivet lines.

and here.

My primer is not very good also.
You may also note that on my AN bolts I write the length number on the head, it makes finding the correct one much faster.

 

[boom3]

Good thinking!

Ya this was a pretty tough part for me. Lots of measuring, looking, measuring, looking.

A small round file is helpful too if you find you have to move your hole over a tad. Start with the smallest bit you can and slowly work your way up.