wing jig ( Questions)

Ok guys I have decided to not build a foam wing but to build a built up wing using a wing jig I know you use arrow shafts ( do they need to be a tight fit on the ribs). How big do you make the jig blocks and how hi off the table do you build the wing.And what is the easest way to build it what I mean is how do you make sure all the ribs are level.

When you stack your ribs to sand them to shape, you drill
your holes in the ribs for your rods to go through. (while they're
stil stacked) All the ribs will line up straight. As far as how high
you are off your building table, just whatever your confortable with.
As long as your rods are supported, you'll be ok.

What I did was make two plywood ribs for the center rib and two for the tip ribs. I would make these slightly oversize at first, and then drill two holes in the center at the appropriate place for the rods. I would bolt these together with the same size bolts and then sand to shape while flipping one over periodically. That way I had bookmatched them for an exactly equal airfoil shape tope and bottom while ensuring that the rods were exactly in the center. You end up with two end blanks and two center blanks, but that is OK. You have a spare in case you ever need it.

Now cut the balsa blanks for the ribs you are going to make (cut them oversize) and drill the holes in them. Bolt the assembly together and then shape the ribs.

Now, you will have a symmetrical airfoil on your ribs and you have made sure that the rods go straight through the ribs keeping everything straight.

And if you build your wings like Al (where the airfoil isn't symmetrical and you have purposely added dihedral) you can still cut the rib patters for the root and tip ribs out of plywood and drill the holes for the rods in the appropriate locations. Then, once again, bolt the stack of rib blanks together and sand away.

If you want to be exact according to the plan, when doing a tapered wing, you will need to make the root rib pattern slightly larger, and then sand the bevel on the ribs square after shaping them. Otherwise, you are probably "close enough", especially if you use cap strips.

Stephen:
I would highly recommended using one of Tom Morris's methods. Lincoln Log or Millennium Wing. Both provide a very straight wing and the methods are much easier then a Jig. The Millennium method is extremely fast. Tom's web site is tomsbuildingservice.biz and there is a lot of info there. You can also call him at (256) 820-6970. If you want to go one step better there is also Bob Hunts Lost Foam Method, which is the most accurate way to build a wing, and is also very easy. Bob's E-mail is [email protected]. There has been a lot of info also published in Stunt News.

Stephen, two things with the arrow shaft method of wing jigs. One, the table the jig sits on must be flat. Two, the ribs must have a slight drag on the shafts. If they are too loose, it is easy to get one rib too high or low.
As to height of the ribs from the table, what ever is comfortable for you as stated earlier. Mine is about three inches above it. My jig has two "Z" shaped aluminum stands, one at each end, screwed to a large board that is 24" by 50". On top of these is where the two shafts rest with a hold down bar across them, held in place with a 4-40 bolt and a wing nut. You can sight down through the inside of the tubes and if you can see the other side, they are straight. I have yet to see around corners .

Have a look and read here: Some pictures will give you all kinds of idea's.

http://clstunt.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=3438&forum=DCForumID1

http://clstunt.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=3128&forum=DCForumID1

"Drilling" holes in your balsa blanks will result in a ragged hole. I make my rib patterns, root and tip, from aluminum. The pattern have accurate 1/4" holes (2 of them). When making the rough balsa blanks, use the aluminum pattern to put 1/4" holes in the balsa blank, one rib at a time. Clean, round holes are important! So I use K&S 1/4" brass tubing sharpened on the INSIDE, using a worn-out X-Acto #11 blade. (the outside should be polished with some 1000 paper to remove any burr). Push and twist slightly, and the holes for the 1/4" wing jig rods will line up perfectly. Also, when putting the blanks together for "sandwich" shaping, I use another couple pieces of 1/4" brass tubing (which simply HAS to fit perfectly).

His ribs have laser cut holes.

If you are like me and get your holes off center, be sure and mark which side of the rib is the top side.

LAST EDITED ON Aug-27-03 AT 05:29 PM (CDT)
 
here is how I do it

I started with the GREAT PLANES wing jig
but I put it on a longer board rather than the pieces of wood supplied in the jig set

I can do the entire wing sheeting and all right in the jig

take notice that both wings are different

see below