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Jigs

I built jigs for my fuselage, tail and wing kits, wing tanks, ailerons, and flaps while building my RV-8.  Here's how I did it.  You should be able to use some of the ideas here.

Fuselage

It's great to not have to build one, but I ended up having to build two due to moving.  It was a pain to ensure everything was level, plumb and true before drilling and riveting.  But all the hard work paid off.  I riveted the skins on from the tail to the front.  There were two holes on either side, one in the F-815A Seat Rib and one in the F-823PP Skin.  You used these holes to ensure your fuselage was not lopsided.  The plans said the holes should be close together, but didn’t need to match perfectly.  I was happy when after two jigs, the holes lined up and I could insert a cleco in them.

My cleco'd fuselage in my first fuselage jig, built and used first by my buddy for his RV-8.The good news was that after the fuselage came off, I covered the top with wood, and had a big workbench.  Lots of space to spread out.

Here’s a picture of the “porcupine” in North Carolina.  Mine was the second fuselage built in this rig; my buddy and I both used it for our RV-8s.  Because we moved it around the uneven hanger floor, it wasn’t completely level.  I used shims below the F-887 on each cross member to ensure everything was correct.




I built my second fuselage jig, and bolted it to the floor.

This picture was taken the happy day I permanently removed the riveted fuselage.  When I built this jig, I bolted it to the floor so it wouldn’t move.  Then I used a planner to get each of the cross members perfectly level so I didn’t have to mess with shims.

When I moved again, I passed this one on to another EAA member who was ready to start his RV-8 fuselage.

Tail and Wing

I know the new directions don’t require or even suggest building a tail jig.  For the older kit, we made a simple one that we used for the tail and then modified for the wings, so it really wasn’t a lot of wasted effort.

It was a simple H-shape, which you could build out of whatever materials you had handy.  I used wood because I could easily drill holes anywhere I needed them.  The only “critical” piece was the horizontal cross-member.  You want to make sure it is flat with no warp or twist.

Unfortunately I didn’t take any good pictures as I built my tail kit.  I was too busy building to stop and take pictures.  But you can see the jig I used for the wings in this picture.  The uprights are the same ones from my tail kit; I just changed the horizontal parts.

Wing jig using uprights from my tail kit jig.

Make yours look like this and you can use it on all the tail parts, and with minor mods, again for the wings.

Tail jig diagram. With minor mods, you can use it for the wings, too.

None of the measurements are critical.  Place the horizontal cross member at a height that is comfortable for you to work over.  Ensure it is long enough to hold the entire horizontal stab between the uprights (102in minimum).

Drawing 12A shows the wing jigs.  The measurement is 114” across, so if you are going to build the jig to help with the empennage, you might as well build it 114” from the beginning. Then when you are ready for the wings, just raise the horizontal bar up to the top, out of the way.

I added the vertical stab to the picture so you could see how the parts were held in place.  The main spars were held in position with some angles and screws run through the hinge-bolt holes.  You can align these angles by running a piece of string through the holes you drill in each.  Make sure they are aligned and level.  Then hold the piece upright with temporary support and threaded rods through the alignment holes.  You can make it plumb by using a plumb bob at the alignment holes., or putting a short screw into each alignment hole and setting a level against them.

Wings in their jig.You can see in the picture that I used some angle iron for the cross members that actually hold the wings.  Van’s Drawing 12A shows the wing right next to the upright.  If you are going to build one wing at a time, this is OK.   If you are going to build them both at the same time, push the wing out some more.  Leave yourself enough room to get between the wings for clecoing, drilling and riveting the top skins.  I suggest putting the top skin in.  Since you will be riveting it on first, it leaves the open bottom side easy to access for the rest of the building process.




Wings in cradle.Wing Cradle

This is the cradle I used.  It was actually built by another EAA Chapter member.  They are a great source for used stuff.  After his wings were mounted, he didn’t need the cradle anymore.  Thanks Roy!



Wing cradle

Tank, Aileron and Flaps

You will actually only need two jigs; one for the tanks, and one for both the flaps and ailerons.

Some pieces of wood with a “V” cut in them used to be shipped with the kit.  This was screwed and clamped so the parts could rest in the “V” like a cradle. 

Flap and aileron jig diagramThis will hold everything sturdy while you rivet, and ensure there is no twist or warp built into the parts.  The exact shape isn’t necessary, as long as the part can slip into the slot and be cradled securely.  Put some padding on the inside of the “V” to keep the part from getting marred.  When you are clamping and working, make sure you have the wood lined up with a rib.  You wouldn’t want to dent your skin.

The wing jig looks like the drawing, except instead of cutting a “V”, cut a curve the shape of the tank, just like you did for the cradle.

I drew a centerline down from the bottom of the “V” and tank curve.  I then drew a line across my workbench.  I lined up the jigs using these lines, spacing them so they aligned with support ribs.  Then I clamped the 2x4 lip to the bench, and was ready to rivet.

Trailing Edges

I also built a jig for bending of trailing edges, which I describe here in Working with Aluminum Skins.


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