NorthernRV4
Well Known Member
Hi Guys
I thought I'd share my experience here to get opinion and at least warn others of possible pitfalls. First off I took over the building of a largely unstarted -4 kit but one item that was mostly finished is the rudder so I didn't get the chance to learn there. I read through the instructions and studied the drawings until I had a good understanding of how the right hand elevator goes together. I spent a great deal of time laying out the structure and stiffeners on the inside of the skin and carefully fabricating & fitting the stiffeners, drilling and dimpling everything... all can go wrong so easily.
I made a critical error when interpreting sketch SK6-2 and thought the spar ran parallel to the skin edge, unfortunately I've come to realize it does not. Looking back I don't know how I made this obvious error as I had confirmed all my dimensions before I picked up any tools. The stiffeners are drilled and cut for a spar that needs to be angled .68deg (5/8" at the outboard end) further away. The angle of the stiffeners doesn't concern me a great deal but the fact that their ends are greater than the prescribed 1/8" from the spar web does. I thought about making them longer but at worst I'm only adding 5/8" so it doesn't leave room to add a rivet for most of them. I think I'm gonna end up replacing the skin and building new stiffeners. Thoughts?
I thought I'd share my experience here to get opinion and at least warn others of possible pitfalls. First off I took over the building of a largely unstarted -4 kit but one item that was mostly finished is the rudder so I didn't get the chance to learn there. I read through the instructions and studied the drawings until I had a good understanding of how the right hand elevator goes together. I spent a great deal of time laying out the structure and stiffeners on the inside of the skin and carefully fabricating & fitting the stiffeners, drilling and dimpling everything... all can go wrong so easily.
I made a critical error when interpreting sketch SK6-2 and thought the spar ran parallel to the skin edge, unfortunately I've come to realize it does not. Looking back I don't know how I made this obvious error as I had confirmed all my dimensions before I picked up any tools. The stiffeners are drilled and cut for a spar that needs to be angled .68deg (5/8" at the outboard end) further away. The angle of the stiffeners doesn't concern me a great deal but the fact that their ends are greater than the prescribed 1/8" from the spar web does. I thought about making them longer but at worst I'm only adding 5/8" so it doesn't leave room to add a rivet for most of them. I think I'm gonna end up replacing the skin and building new stiffeners. Thoughts?
