Chris Tracy
Bending Brake Center_Section Control_Horns Controls Engine Engine Mount Fuselage Landing_Gear #1 Landing_Gear_#2 Fuselage Tank Sand_Blaster Seat_Belts Tail_Hinge_Routing_Jig Tail_Wheel Main Wheels Wing_#1 Wing_#2 Wing_Fuel_Tank Wing_Rib
Wing Rib
MY WING RIB JIG:
My jig is made up of two 3/8" plywood 70" x 10" pieces glued (Elmer’s wood glue)
together to form a rigid base. I just glued the pieces together while they lay
on the garage floor. On top of this using 3M spray glue I attached the wing rib
drawing that I plotted from the dimensions on the plans. I did not use the full
size wing rib drawing supplied with the plans because it did not match the
measurements from the plans (advice from a bunch of builders). Do not use
Elmer’s glue to glue the wing rib drawing down. It will cause the paper to
stretch, warp and have wrinkles. I should have known better. But, on the bright
side, the second time I plotted the wing rib it only took me half the time
(about an hour). When laying the paper on the plywood base, tape one end around
the plywood. This way you can pull the pattern tight while it is in the air and
lay it down smooth. With 3M glue you only get one chance. On top of this I have
a sheet of 1/4" clear Plexiglas held down by screws (as suggested by Steve
Eldredge). Using 3/8" Plexiglas I cut out 1/2" x 1/2" blocks then glued (special
glue for Plexiglas) the blocks along the rib outline. I cut out spacers for the
spars from this material also. It takes fewer blocks to hold the shape than you
think, I have way too many on my jig, but it works. I initially use these
non-moveable blocks to hold everything, but have since removed some of them so I
could get the pieces to slide in with out scraping off the glue. The glue will
not stick to the Plexiglas and I can pop my wing rib out with out hurting the
jig or rib. (Cost about 15 dollars and a 1/2-day to build, including picking up
the materials)
When building the ribs I tried using staples to hold the 1/16" plywood gussets
on, but I did not like the way it looked after I removed the staples. I’m too
cheap to buy a bunch of clamps so here is what I am doing. I glue the rib
together without the plywood gussets. Let it dry for about 12 hours, and then I
carefully remove it from the jig. With it out of the jig, I glue on the plywood
on one side of the rib. To hold the plywood while it is drying, I use "Large
Binder clips" that I purchased at the local office supply. They have a 1"
capacity and are CHEAP compared to real clamps (5 dollars for 12 binder clips).
They work great with the T-88 epoxy I am using. I can now produce great looking
ribs with no holes in the plywood, I don't have to waste and remove staples and
my jig looks as nice as the day I built it.
Chris
