Recently completed riveting the rear seat rib subassy per drawing 65 and a fellow RV8 builder comes by and says "oops" the rear spar attach bar (F-806C-1 and D-1) is upside down. There is a slight taper on the outboard ends of the attach bar and I currently have the taper on the top sloping down. No notes on the drawing or in the instructions about orientation. He says the wing skin dihedral will conflict with orientation as is. Solution? Problem? Drill out the spar attach bars and flip, derivet part of the F-826 and F-827 bottom skins to add some taper to the bottom of the spar attach bars in place.
Van's Air Force
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Rear Spar Attach Bar Orientation
- Thread starter davep1969
- Start date
It might be all right
I screwed up here too but I found out much to late for an easy fix. I put one of those bars, the forward one, in with the taper on the top and the rear bar with the taper on the bottom. I went ahead with the build but when it came time to drill the rear spar attach bolt, I had to narrow my area to drill by about half of what most people have, BTW, it is pretty darn small to begin with. I also had to set my wing incidence .1-.2 degrees more than I wanted to due to the edge distance on the rear spar. Everything came out alright and I made it work, you probably could too, but even with the outcome, if I had been as far along as you and found the mistake, knowing what I know now I would correct it, there just isn't much room for error here. It also took me 3 days to drill the rear spar attach and this was one of the reasons.
Randy
Getting Close
I screwed up here too but I found out much to late for an easy fix. I put one of those bars, the forward one, in with the taper on the top and the rear bar with the taper on the bottom. I went ahead with the build but when it came time to drill the rear spar attach bolt, I had to narrow my area to drill by about half of what most people have, BTW, it is pretty darn small to begin with. I also had to set my wing incidence .1-.2 degrees more than I wanted to due to the edge distance on the rear spar. Everything came out alright and I made it work, you probably could too, but even with the outcome, if I had been as far along as you and found the mistake, knowing what I know now I would correct it, there just isn't much room for error here. It also took me 3 days to drill the rear spar attach and this was one of the reasons.
Randy
Getting Close
With these modern kits, there are very few places where the builder can mess up bad enough with primary structure to make the airplane potentially dangerous - unfortunately, rear wing spar attachment bolt edge distance is one of them. (The other, in my mind, is horizontal tail attach bolts.) To avoid unpleasant edge distance surprises later on, I'd probably fix it now if it were me.
Paul
Paul
Okay 3.0 hours of deriveting, disassembly, fighting a couple rivets that did not want to come out, clean holes, debur as necessary, reprime all parts. 1.5 hours of reassembly, slipping the rear spar attach bars into place with the correct orientation and re riveting everything back to where I was Friday afternoon when this "oops" was discovered. I can only image how disappointed I would be several months down the road when it came time to install the wings and proper edge distance became a real issue.
Now, how did this happen I have asked myself several times over the weekend. As an A&P IA, former Chief Inspector in charge of Quality Control for a large helicopter firm, I felt I was as cautious and careful with details as most, if not more. I remember clecoing the rear spar attach bars in place and one was inverted as the outboard tapers did not match. I flipped one around so they both matched. I looked at it for a couple seconds and thought to myself, "Can it be installed wrong?" This is where complacency and confidence in Van's caught me off guard. There was a note in this section regarding the orientation of the gussets but nothing regarding the spar attach bars. I told myself in a fraction of a second, there were no notes on the orientation. It is either "Murphy Proof" or it doesn't matter.
This morning I looked in the instructions later in the construction manual and found the big bold statement regarding edge distance when locating the rear spar attach bolt. What could be better? A note in the section when riveting the rear spar attach bars and/or on drawing 65, even better would have been one or two holes out of alignment with the rest of the rear spar attach bar to bulkhead to make the orientation "Murphy proof". Lesson learned, Always watch for "Murphy" to sneak into your practices. If not sure ask, reread, double, triple check the drawing. When you ask yourself, "Can it be installed wrong?" Make sure.
Thanks to Paul and Mel for their speedy response and confirmed my gut reaction that now is the time to fix, regardless of how bad we hate to undo something. More than worth the small price of admission to these forums!!
Now, how did this happen I have asked myself several times over the weekend. As an A&P IA, former Chief Inspector in charge of Quality Control for a large helicopter firm, I felt I was as cautious and careful with details as most, if not more. I remember clecoing the rear spar attach bars in place and one was inverted as the outboard tapers did not match. I flipped one around so they both matched. I looked at it for a couple seconds and thought to myself, "Can it be installed wrong?" This is where complacency and confidence in Van's caught me off guard. There was a note in this section regarding the orientation of the gussets but nothing regarding the spar attach bars. I told myself in a fraction of a second, there were no notes on the orientation. It is either "Murphy Proof" or it doesn't matter.
This morning I looked in the instructions later in the construction manual and found the big bold statement regarding edge distance when locating the rear spar attach bolt. What could be better? A note in the section when riveting the rear spar attach bars and/or on drawing 65, even better would have been one or two holes out of alignment with the rest of the rear spar attach bar to bulkhead to make the orientation "Murphy proof". Lesson learned, Always watch for "Murphy" to sneak into your practices. If not sure ask, reread, double, triple check the drawing. When you ask yourself, "Can it be installed wrong?" Make sure.
Thanks to Paul and Mel for their speedy response and confirmed my gut reaction that now is the time to fix, regardless of how bad we hate to undo something. More than worth the small price of admission to these forums!!
After reading and contemplating about this thread I just checked my rear spar area the other day. I found the same thing you did!!! I installed it upside down. I was getting ready to rivet on the top rear skin of the fuselage so it was very difficult but I swapped the spar bars around.
It was a day project by the time I was done but I think it was worth it. Now the angle is facing down and it eases my nerves.
I like you are a A&P, IA and run my own restoration shop. We all learn to check and recheck, I too thought this was murphy proof or Van's would have added a note. I was very dissapointed about this and lost some confidence, there have been notes for other things that are not nearly as important. But there have been other things where I have lost some confidence in Van's as well, mainly customer realtions and being a little arrogant at times. But for the money and compared to most of the rest of the industry Van's still puts out a wonderful product.
It was a day project by the time I was done but I think it was worth it. Now the angle is facing down and it eases my nerves.
I like you are a A&P, IA and run my own restoration shop. We all learn to check and recheck, I too thought this was murphy proof or Van's would have added a note. I was very dissapointed about this and lost some confidence, there have been notes for other things that are not nearly as important. But there have been other things where I have lost some confidence in Van's as well, mainly customer realtions and being a little arrogant at times. But for the money and compared to most of the rest of the industry Van's still puts out a wonderful product.
Josh,
I emailed Vans after the incident and explained that they had three bold notes regarding other rather minor issues in that section but nothing regarding the rear spar bar orientation. Nothing in print or on the drawing. Scott replied that they are reviewing the situation and agreed there should probably be a note in that section. I know my lesson was learned and am planning to have my fellow RV8 builder, also an A&P IA over more often to give me that extra set of eyes on things. I did it as a practice when working on helicopters and fixed wing, no excuse for not doing it now.
I emailed Vans after the incident and explained that they had three bold notes regarding other rather minor issues in that section but nothing regarding the rear spar bar orientation. Nothing in print or on the drawing. Scott replied that they are reviewing the situation and agreed there should probably be a note in that section. I know my lesson was learned and am planning to have my fellow RV8 builder, also an A&P IA over more often to give me that extra set of eyes on things. I did it as a practice when working on helicopters and fixed wing, no excuse for not doing it now.
