Q/A on construction steel RV-3B fuse jig (on wheels)

After looking through the pictures on Fred Bauer, Jr?s RV-3B picasa page, I noticed the jig that he built the fuse on was fabricated out of steel. That got me to thinking about how I might build a fuse jig that would make better use of our tiny two car garage. Something that would keep me from parking outside, like I had to do with the RV-6.


The RV-3 firewall bulkhead (widest part) is 24? wide on the plans and I have 35? inches of space between my Miata and the garage wall. Built properly I could put castoring wheels on it for easy access during a work session, then I could roll it against the wall, lock the wheels and then pull my car back in for the night.

When the canoe needs to be flipped I could weld on tabs to the jig near the spar location and tailcone bulkhead, giving a nice way of working on the canopy, interior, etc. Maybe even chop off a foot of the legs to lower it all a bit. Could move it anywhere I needed it. Might even be able to mount the engine and cover the whole thing with two sheets when I needed to.

As the jig goes aft towards the tail, it would taper to minimize creep into free garage space.

Stan has a welding station in his hangar out at 52F and I am pretty sure he would let me pay for the parts and electricity used.

Throwing it out here to see if there are any dealbreakers that I haven?t thought about. If properly braced I don?t think twist would be an issue.

Doesn't sound like rocket surgery, but all my math classes had to do with accounting, so I throw it to 'the collective' for input.


b,
dr

Should be a piece of cake.

But then, I have been welding steel an eternity or two longer than I have been riveting aluminum.

Two big potential "gottchas" I see.

First is to built it straight/flat. Pretty easy really.

Second is to keep it that way when it sits in your garage---------is the floor flat????

You want it to move around on casters, so be sure you always put it in the same location ---which you have verified is going to give you a flat work surface---when working with it. Mark the wheel positions with tape/paint etc.

I would suggest checking the floor before you commit to anything.

Good luck.

concerns

Doug,

I would be concerned about it being on wheels and being able to maintain straight, plumb, and level. Even a welded steel frame is going to move some. The floor is not level (consistently level), each time you move the jig you would introduce new surfaces for the wheels to rest on. I have several machines and once they are dialed in you do not want to move them to another spot, you would have to dial them in again.

I used a steel frame for wing jig and getting it plumb and level and straight took some care, I can't imagine moving it about and counting on it remaining ok. The 3 is not prepunched as you know and keeping it straight, plumb, and level is critical for best performance.

edit: I went with a steel jig for the emepennage and wing because I was concerned about the movement of a wood jig due to changes in temp and humidity. Some guys say the steel is overkill, I guess it boils down to how concerned you are about keeping it straight and not introducing twist and warps etc.

Just some thoughts,
good luck,
jim

Lot's of options

I picked this jig up locally and it has more than one 3 to its credit. I think we can get a little hung up on the jig being perfectly straight and level, but I do agree that it should not move around. It also needs to be secure enough to handle riveting and the occasional hip bump. Looks like Fred bolted his to the ceiling and probably to the floor. That jig is a work of art, but so is his 3.
The important thing is that the bulkheads are square to the center line, to each other, and there are no twists in the longerons. In other words, it needs to be square in the jig, but the jig does not need to be perfect.
I would have concerns moving it around unless is was built like a battleship.
I intend to secure this jig with shot bags. [/IMG]

Doug
Follow JonJay's advice. The jig does not have to be square or straight, it just has to hold the bulkheads and longerons straight and square. Van addressed this many years ago in an RVator when a gentleman was selling steel jigs for thousands of dollars. I borrowed a wooden jig for my 2 RV4's, and built the one for my RV6. It took all of half a day to build the wood jig.
Just follow the manual, follow the manual, follow the manual.
Spend the time building the plane, not stuff that won't make a difference.
Best regards,

Doug,

True, the jig does not have to be straight. However, in the end the you want the airplane to be straight and fly straight. The question is, can you put the jig on wheels on and move it around the shop and count on ending up with a straight airplane in the end.

My point is that if you put it on wheels you are going to spend hours with plumb lines and strings double checking every time you move it. If the jig is going to be stationary, you can argue steel vs wood all day. If you are going to plan on moving the jig around the shop you will introduce problems. Building a 3 or a 4 is a lot different from the new kits.

jim

The quality of the finished product will be directly perportinal to the the amount of workspace, lighting, quality of tools and straightness of jigs.
RV3 pilot
buuilder x 2

Doug,

Walk down the street to your neighbor who built the Midget Mustang and see if you can borrow his Mustang Aero DVD. Look under Midget Mustang, then construction, then jig. You will see the most beautiful jig you have ever seen. It is also on wheels, but as suggested on earlier posts the floor is marked, so you can put it back in the exact spot to insure it is plumb, level and square. The only improvement your jig could have is to forget the paint and have it chromed!

Jim