Building the wing jig: I made my jig so that both wings could be built back to back. I made mirror images of the angle irons for hanging the spars. I used 2×2 angle iron and made the first set as the book shows and then made the mirror images. My 2×2 angle iron costs $4.50. I had out local ironmonger cut 8 pieces 6 inches long. The cutting costs was $.50 each and the weight of the iron was $.50 for a total of $4.50. I made my jig of 2 2×4’s laminated together (straighter than 4X4 and less chance of warpage) and added additional 2×4’s on the area of the angle irons so that I could mount both the right and left wing at the same time. I made the upright 2×4’s so that they could be tilted back and forth to check level on a daily basis. The bottom is fixed and the upper part swings. Put an oversize hole in the upper stanchion and it can quickly be re-leveled and clamped by tightening the bolt. Your bench has to be in the middle of your workshop. The advantage is that you can sort the skins and parts, right and left, and you can put together things back to back thereby making the same mistake twice(!). You do have to have help (wife, lover. friend, or other) to help you dismount and mount the spars and ribs to do the bottom skins. I made 2 tables 2’X8′ and screwed them together. I used 3 sheets of 4X8 3/4″ plywood cut lengthwise to 2’X8′ on supplier’s panel saw and used 2X4 studs, selected from stud pole for straightness. Put shelves in below the table- they save a lot of steps to layout parts and tools. It works.
Wing jig height: If I had it to do over again, I would lower the entire assembly approximately 16 inches. This would put the leading edge at 65 inches off the ground and the forward spar at 57 inches. I’m not sure if this distance will have any bearing on how the flaps and ailerons are installed, but I can’t imagine how it would.
Wing jig: The jig design in the manual works fine, but it has several shortcomings. It would be more convenient if the wing assembly were lower. Most of the time consuming work seems to be on the leading edge and you spend a lot of time on short ladders or stools. I personally do not want to give up the table. It is just too useful and you need it to properly install the aft spar center supports. The table could probably be lower and still be functional and I see no reason why the spars could not be installed closer to the table.
The wooden 4 x 4s uprights are inexpensive and functional, but you have to be willing to check and re-adjust your alignment frequently. The uprights will move as they continue to cure. We used some very nice cedar uprights at Ottumwa and aligned everything with a transit. Within a day or two I had to remove the lower inboard fitting and add a .020 shim. By the time I got the skins fitted I had added 3 more.
The inboard jig bracket on page 19 is too long. The distance from the C/L of the Spar Pin Hole to the outboard edge should be 7/8″ instead of the 1 1/8″ shown. Also the location of the four holes used to attach the inboard brackets to the jig upright place the outboard end of the wing so close to the outboard jig upright that it is very difficult to work out there. The jig brackets themselves, which are made of 2x material, place the wing assembly so close to the uprights that they get in the way.
I have already purchased the material to build my own jig which should solve these problems. I will basically build the same jig but substitute two 7’ aluminum 4 x 4 box sections which have a 1/8″ wall thickness. We are fortunate to have several metal supply houses in San Diego. I am sure that they are not available everywhere.
I will build the brackets out of a 3 x 3 extrusion 3/16″ thick and move the spar pin, cleko and plumb bob holes accordingly. I intend to use slotted bolt holes in the brackets to make it easier to adjust their alignment with a transit and then pin them in place. A little more expensive but they will not warp and unless the floor moves (a possibility in SoCal) they should remain level, and the critical dimension between the spar fittings should remain fixed.
While on the subject of leveling, when you install the outboard rib and the outer aileron cove rib they will be fitted between the jig and the spars raising both spars at the outer end by the thickness of the material. The manual says that that is okay and within tolerance. I don’t know how to check almost level with transit or any other device so I placed shims between the inboard spar fittings and the jig brackets. Works fine. Level is level so you don¹t have to worry about whether you are still within tolerance or not.
Another wing jig idea: Here is a Wing Jig building idea that I came up with. “While strolling through the Base (Home Base and/or Home Depot) one day” (but not in the marry marry month of May), I happened to see in the “fence” department some 8 foot by 2-3/8″ dia. tubing that would make great vertical posts for the wing fixture. In fact, they also have the clamps that will slip around the tubing to allow attachment of the home made wing brackets that we will build out of Alum. angle stock. Using metal will solve the problem of having wood move with the ever changing moisture conditions.It is also very cost effective – just over $20 for all the pieces.
Another wing jig method: I used steel 2×4 x8′ and 10′ ‘wall studs’ as longitudinal stiffeners under the wing table in place of the 2×6’s suggested in the plans. The 10′ studs will be used to lap the 8′ studs when I join the 8′ tables. The steel studs are really cheap, do a good job keeping the table straight and they don’t warp. I used wall jacks for the vertical posts, using 3″ muffler clamps to secure them to the table and to attach a wood surface to the post for mounting the components. I also used large lag bolts on the bottom on the table legs so that I can level the table with a turn of the lag bolt. The bolts set in recessed holes cut in horizontal 2×6’s that set on the floor (the floor jacks set on the same 2×6). After everything was level the leg braces were added.
Aft spar supports: The aft spar supports in the manual are economical to make, but are rather clunky. 3/4″ black pipe flanges attached to the table, with a short length of pipe threaded to them with a threaded plastic stub cap make for easy and perfect height adjustment. The thin pipe also gives you more room to work around than the 2x4s suggested.
Easier assembly: By the way, I found it easier to initially assemble (cleco) the wing parts together laying flat on the table after having first hung the jig attach brackets on the 4x4s. Then I will rehang the whole system on the jig. Easier to work on the table for drilling out the rib to spar attach holes, etc. My jig is very simple. I screwed a 1/2 in. plywood plate (8×12 inches) to the bottom of my 10 foot long 4x4s then screwed the tops to the roof trusses, plumbed them and then screwed the plates to the CONCRETE floor. Nice and solid. My table is my table/jig I used for the tail section (made of 2 solid core doors on 2×6 legs–simple and easy to build and VERY STABLE). I can slide the table under the wing or out at my leisure, but actually leave it to one side. By having the uprights firmly attached to floor and ceiling, there is less risk of movement than if it were attached to a table. My jig is working very well! Staying straight and plumb. and much easier to work on than if on or above a table. Also I mounted the top spar (& bottom) about a net of 9″ lower than the total height suggested in manual (w/table). It is much easier to work on. (I’m 6′ tall) Don’t have to stand on buckets all the time. Jig attach brackets as drawn on pages 17-20, are actually for the right wing. Spar cutoffs were done with a 4″ thin cutoff blade in an air grinder tool. Does a very efficient job. (Hearing protection a must!)