Laser Woes...

Well it's the middle of May, 2003, and I just started on the wing today...

Unfortunately I have again found more pieces cut incorrectly. The two Dihedral Braces (front and rear) which are cut from aircraft ply, are extremely off when you lay them on the plans. They are off as much as one half inch in some respects/areas... the dihedreal angle on one end is 1/2 inch different than the dihedral angle on the opposite end of the same piece! The slots cut for interlocking with the ribs were almost all off by 1/16 to 1/8 inch as well.

This is obviously not acceptable and frankly not what I expect from a professional Laser Cutter (AAKC). Between poorly/incorrectly cut parts, incorrect wood stock, and some damage to the kit in shipping, I've now reached the point where the only laser cut parts that I'll use in the entire plane are the ribs and flaps. Everything else has had to be recut by hand. I had to order new wood from Lone Star Balsa, so I'm in a holding pattern until it comes in.


Pics of the Problem

Here are a few pics of the problematic front and rear dihedral braces for my SBD. It would have made for quite an interesting wing with 7 degrees more dihedral on one side than the other! Assuming of course that the interlocking rib slots were any where close to where they should have been.

Tip for the day... always check all your laser-cut pieces to the plans before hitting them with a drop of glue!

PIC #1 - Rear Dihedral Brace over plans

PIC #2 - Front Dihedral Brace over plans

PIC #3 - Front Brace to Rear Brace alignment


PLAN ALERT

While waiting for my new wood to arrive so I could re-cut the dihedral braces, I decided to go ahead and make my templates to cut them from. I put mylar over the plans and traced out the dihedreal braces. After cutting out the templates from the mylar, I laid them onto the wing top plans. Surprise, they don't line up to the ribs on the wing plans!

The dihedral angles seemed to be OK, but the slots for the interlocking rib construction were off as much as 1/8" on 3 or 4 of the center ribs. Glad I cought this before recutting them with the new wood! The plans may have been corrected since my printing, but you want to make sure that the rib spacing on your dihedral braces match that of the wing plan.

By the way, the error in the drawings for the braces were not the same errors that were made in the laser-cutting, and were not nearly as bad.


"Starting on the Wing"