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RV4 Jig Spar height and length

Sanch627

Member
Getting ready to put wing spars in jig, anyone know the optional height and length to set the spars in the jig.

Chris RV 4 #4633 aka N1212R
 
What I did

I cant actually tell you the height I used, as it was 25 years ago..but here is an old picture of how I did mine that will give you an idea. I tied 4x6 posts to my basement rafters and epoxied them to the floor, then attached aluminum angles to the post in which I rested/clamped the spars. i set it up so both wings were being built simultaneously and could perform the same tasks on each wing. i was comfortably able to shoot the L/H skin rivets alone by reaching up in through the lightening holes to hold the bucking bar while shooting. The height from the floor is important for overall comfort. You can see in the picture I used a couple "kickstands" on the rear spar to keep everything level. With the plumb bobs installed per plans, it was very easy to keep everything perfectly true. My assistant in the background was too young to buck rivets until later in the project, but he kept me motivated.
 

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set it up so both wings were being built simultaneously
Didn’t do it during my build, but definitely a head scratcher and time saver, good tip!

30 years ago...
 

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Been There - Done That

Having done this twice already - my only suggestion would be to locate the main spar to a height that (comfortably) allowed riveting on the bottom skins when closing out the wing, because you have to let the skin go under your arm pit as you proceed with the riveting process.

Too high, and you have to stand on something to make it all work out ergonomically; too low, and you are "squatting" uncomfortably.

If the distance to your arm pit is 50" (mine is) for example, I would pick a height that allowed me to bend my knees just a little for comfort and convenience - that height would be where I locate the main spar.

YMMV - and probably will.

HFS
RV-4 S/N 1136
HRII (RV-4 S/N 3392)
 
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