Rear Wing Spar Web W-7A

I'm starting to plan for my next stage of construction (wings) as I hope to be finished the empennage kit by the end of the year. When I purchased my second hand kit it ended up that I was missing the rear wing spar webs. I emailed Van's to find out the cost of new ones but I expect the shipping to be more than the parts since they are 112" long. A local builder suggested I contact a somewhat local aviation sheet metal shop to have them bend them up. Here's the question I have, does grain direction in the material play any part here? I have never heard of sheets 120" wide so I expect Van's bends with the grain instead of against it but I don't have examples to compare to. Does anyone know from their own kit?

Jim,
Since the parts are match-hole like the rest of the kit, I recommend you order them from Vans. If you want to save on the shipping charges, have them sent with your wing kit. The horizontal stab goes together fairly quickly so it won't set you back too far by waiting.

If you have them bent by a local shop, you'll need to build a jig to ensure the parts are built straight. This is a no brainer with the factory parts, no jig required.

Brian

bscycleman said:

Jim,
Since the parts are match-hole like the rest of the kit, I recommend you order them from Vans.

Click to expand...

This is the RV-4 forum so I assume that is what he is building (and it is part of his user ID)
The RV-4 is not match hole...

The RV-4 spars are all cut length wise from a 12 ft sheet so having them made local shouldn't be a problem. The plans were originally drawn to allow scratch building from common sheet stock.

Thanks for the clarification. I saw W-7A and made a bad assumption. I didn't have my plans handy for reference.

Brian

No problem, yes it is a RV-4 wing kit and I already have it, minus the rear wing spar webs. They are not pre-punched or jig drilled at all, just simple "S" shaped formings about 4" tall and 112" long .040". I suspect they will be pretty hard to ship economically so I will see if I can get them locally first.

w-7a by Jim Soutar, on Flickr

w-7a_2 by Jim Soutar, on Flickr

Make sure your bends are per plans at 1/8" radius, and prior to bending, smooth out the edge as much as possible to prevent cracks. It is good practice to make the part long, and trim back the ends to remove any fatigue from the edge.

Rear spar

Jim,
Mine were missing also. I decided to pick up a 10' sheet and have the local sheet metal shop bend it up. It took him 3 try's - he had to reset the brake for the 1/8" radius and then make sure his brake bends straight, many have a twist from one end to the other. Heat and air shops don't have to be that precise. Make sure your metal is to specs.
Mike

It's not too bad to ship.

I had to order a rear spar when building my wings. It was about 50$ for the part, and about 35$ to ship IIRC. It WAS going to cost about 100$ to ship, but if you ship direct to a hub, versus your house, and shipping is easier to swallow.

Get the VANS part, don't roll roll your own. I was going to try that, but if the bends are off just a little, your skins will NOT lay down properly at the spar.

Been there.


Gregg

Keep in mind I would be using a local Aviation sheet metal shop not an HVAC shop and I would expect standard aircraft manufacturing practices would be met. I did contact Vans and shipping wasn't quite as much as I expected (around $100) so by the time I buy two spars and the shipping it's about $200 which is a wash with the estimate from the local shop. I'll end up ordering direct from Vans I think, just less hassle and I know it will be right.

Now to spend a couple hours an make sure I don't need anything else. Seems everytime I place an order I turn around and end up needing something shortly after.