NorthernRV4

NorthernRV4

Well Known Member
Does anyone know if something has changed over the years in the material used to fabricate the VS hinge brackets? My -4 kit is an older kit that is mostly untouched but the previous builder constructed the skeleton of the VS and the hinge brackets are made from .125" Alum angle stock. All references on the plans show .050 steel the same as the HS. Has anyone else heard of this? I'm wondering if I need to change these which would be hard now since they are drilled and riveted to the spar.


Untitled by jim_soutar, on Flickr


Untitled by jim_soutar, on Flickr


Untitled by jim_soutar, on Flickr
 
hinge brackets

when i got my rv-4 kit in 1987 the kit came with angle to make the hinge brackets but shortly after i read in the rvator that they had changed to steel so i ordered them as a replacement part but i don't remember why the change was made but it was not something that had to be done
 
.050" steel vs. .125" aluminum should be about a wash, strength-wise. Aluminum will fatigue over time, so inspecting them at annual would be a good idea. But those brackets should easily last the life of your airframe.

That being said, since it doesn't look like the skins are on there yet, it wouldn't be particularly hard to change them out. You'd need a set of steel brackets that hadn't been drilled yet, and you'll have to match-drill the existing holes in the spar onto the steel brackets. Check alignment carefully before drilling!
 
My very old RV6 second hand tail kit had that style hinge installed. There is mention of these changing in a photo caption in the assembly manual.

My spin on it is the steel hinges can flex somewhat making positioning of the hinges a little less critical.

I changed them out, to make the plane compliant with the later drawings and as previously mentioned, due to concerns about fatigue.

Andrew.
 
For the RV-6x it looks like the change happened in 1992 when the sheet numbers went from 6 and 7 to 6a and 7a.

A visual check looking through all three hinge points will confirm if they are truly lined up. Since the parts were all drilled to fit it might be hard to make the replacements fit the same.
 
Thanks guys, I figured there was a change in design somewhere along the way. My -4 is serial 658 so it's likely before any such design change was made. I will call Vans tech support to get more information on possible fatigue problems that could appear.
 
Edge distance?

Can't comment on alum vs steel, but in your pics the edge distance on the holes looks less than 2d - maybe just parallax?
 
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