I acquired an Adjusto-Jig many years back but have never used it, though I'd like to on a future project. I'm curious how you accurate locate the jig rod holes in a stack of already die cut ribs. I presume you use some sort of homemade template. The mylar one that came with my jig doesn't exude confidence. Any tips would be appreciated...
Thanks,
Gary
Hi Gary,
Yeah, I agree about the mylar template supplied with the jig.
I simply stack the ribs very carefully aligned with a common feature. In the case of the Nobler or SIG Chipmunk that is the trailing edge of the ribs. I carefully locate the best place for the jig holes where the jig pieces will not interfere with construction by using one of the jig rod holders placed on an end rib. Mark the locations of the rod holes then pin the stack together. I made some long pins from .030 music wire sharpened on one end with a grinder and bent to shape on the other end like a T-pin. Hold the pin with a pair of pliers and simply push it through the stack of ribs. One at the Leading edge of the ribs and one at the trailing edge.
Put the stack in your drill press and drill the holes for the jig rods all at once. Sometimes when using kit ribs with cutouts in the ribs it's necessary to temporarily glue small pieces of balsa into the holes in the ribs to allow a location for the jig holes. They can be removed eaisly after construction.
I think some of these might be visible in the wing in the picture.
This sounds a lot more difficult to do than it is. It works very well.
Set the jig blocks on the jig by measuring the rib distances from the plans. I use a long (36 inches) aluminum ruler to measure the placement of the jig blocks and then tighten the screws in the jig. I also use that aluminum ruler on edge to make sure all of the jig blocks are flat since the ajusto jig can be used to build dihedral into the wing.
Check the positions and when satisfied slide the ribs on the rods and rubber band them to the blocks. Easy and works like a charm.
You can build the wing complete except for the bottom center sheeting without ever removing it from the jig. I insert the spars first and glue them in place then the trailing edges then the leading edge and the sheeting. for the sheeting use aliphatic resin glue (like Elmers etc) and simply tapen everything in place with masking tape to dry. I can build a complete wing sans flaps and controls in about an hour...not counting the couple of hours for the glue to dry.
I then slowly slide the jig rods out about two inches on each side and install the controls.
Actually you may want to do this before putting the top front sheeting on.
After everything is dry remove the wing from the jig and install the flaps. Actually this can be done in the jig but I prefer to do it afterwards.
Randy Cuberly