Check those AFT Spar bolts

[rvbuilder2002]

I don’t mind to be singled out if it is done with good intention and constructive criticism.

I had talked to VANS just to make sure my deviation is not of a great concern and they confirmed that as long as it is properly safety wired/cotter pinned. FWIW, my thoughts on the use of a nut plate was due to the fact that since this is not a properly torqued bolt, it has a greater chance of coming loose, hence both the bolt and nut needs to be fixed. I think it is also important to note that the safety wire ought not to go to the slotted bracket, just for the reason you have stated.

The problem with asking this type of question of one person at Van's is that no one person knows the most correct answer to every single question that can be asked (nor should they be expected to).

An actual test rig was built and tests were done to determine what configuration would be the most reliable with the multitude of variables that could be involved in an accident. The configuration specified in the plans is the result of those tests.

I do not understand your concern (and justification?) for not using the nut plate because of concern for it coming loose..... The plans specify a drill head bolt safetied with safety wire.....

 

[Bavafa]

The problem with asking this type of question of one person at Van's is that no one person knows the most correct answer to every single question that can be asked (nor should they be expected to).

There are few of us that are first time or novice builders and we may botch a portion of the build or the assembly. I believe this is why Vans has a builder assist so we can get an expert opinion whether there is a concern for redo or just build-on. I have certainly read many example of both cases here. In general, I respect Vans technical advice very much and outweigh most that I read here with the exception of few like Vic or DanH (don?t mean to single out them). In this case, Vans did not have a concern and did not ask me to change it even though it is an easy change. Now if you built exactly per plan, my hats off to you but I was a first time builder and still novice and eager to learn.

I do not understand your concern (and justification?) for not using the nut plate because of concern for it coming loose..... The plans specify a drill head bolt safetied with safety wire.....

Since English is my third language, I chalk this up as my inability to explain it well. I did not have a concern nor justification for not using a nut plate. It was simply a question to understand and learn. My understanding of the use of a nut plate has been primarily for those area that is hard or impossible to access or inspect. The inside part of the spar is a good example of that which once skinned, no access to the nut will be available. That certainly not the case here as in my plane, I have ample access to both the bolt and the nut and they are secured by a cotter pin for the nut and safety wire for the bolt to prevent it from turning.

 

[Planecrazy232]

.

A nut plate is used for a very specific reason.

In some crash situations the wing may deflected aft which causes the fuel tank to move outboard away from the fuselage.
The design of the joint is to allow the bracket on the tank to pull away from the support bracket on the fuselage instead of the root rib being pulled out of the tank. The nutplate is used to help minimize the likelihood of the of the fastener being able to tilt sideways and jamb up instead of allowing the clevis on the fuel tank to freely slide out. So it is also important to orient the nutplate laterally as shown in the drawings and to tighten the bolt as described in the plans/manual.

I looked at the forward connection on my RV6 plans and it calls out a bolt, washer, and fiber nut. It also does not show the brackets being slotted. Please let me know what I am missing.

 

[JonJay]

I looked at the forward connection on my RV6 plans and it calls out a bolt, washer, and fiber nut. It also does not show the brackets being slotted. Please let me know what I am missing.

I did a quick search for an SB but came up empty. I am unsure of the origination, but the purpose of the "slot" is to allow the Fuel tank to separate from the fuselage without spilling its guts on impact. Kind of a last hope when a situation has turned really bad.
I don't have ready access to this mod but I am sure someone has it at hand.

 

[RV6_flyer]

I looked at the forward connection on my RV6 plans and it calls out a bolt, washer, and fiber nut. It also does not show the brackets being slotted. Please let me know what I am missing.

The slot was a change to the plans. Early plans just had a hole in each bracket with bolt, washer, and nut. New plans had the slot.

Those of us with flying airplanes built to plans may not incorporate all improvements till we have the airplane apart to make access easy. (Will not necessary take apart for a plans update but will incorporate a plans update when the are is accessible because of another change.) When the tanks are off for the safety wire installation on the fuel pickups, that would be the time to add the slot on airplanes built to early plans.

 

[az_gila]

The slot was a change to the plans. Early plans just had a hole in each bracket with bolt, washer, and nut. New plans had the slot.

....

It (the slot in the bracket) was added to the plans in 3-98 and then the hardware call out was further revised in 5-99.

 

[rv8ch]

An actual test rig was built and tests were done to determine what configuration would be the most reliable with the multitude of variables that could be involved in an accident. The configuration specified in the plans is the result of those tests.

This is great information. I would find it really useful in the plans for Van's to note things where they recommend against deviation. I think they are generally pretty good at this, but don't recall this one being mentioned.

 

[Planecrazy232]

It (the slot in the bracket) was added to the plans in 3-98 and then the hardware call out was further revised in 5-99.

Could someone post up a plans photo of this revised front attachment? I want to make this change to my plane.

 

[Chkaharyer99]

Is this whats being discussed?

 

[RV6_flyer]

Is this whats being discussed?

YES that is the area being discussed.

 

[Chkaharyer99]

Thanks Gary. I will check mine and see how its done.

Great thread Vic. Thanks for taking the time to post these types of issues. It really helps to keep us safer.

 

[skylor]

Deviation From Plans

This is great information. I would find it really useful in the plans for Van's to note things where they recommend against deviation. I think they are generally pretty good at this, but don't recall this one being mentioned.

This statement strikes me as a little bit silly. I think you'll find that in general, unless Van's provides an "option" with plans they will recommend against just about any deviation to the plans. I don't think the plans need to note this for specific items.

Skylor

 

[az_gila]

Could someone post up a plans photo of this revised front attachment? I want to make this change to my plane.

Not quite as cleanly explained if you just use the RV-6 drawings...

And, to show model differences, the -7 slots the fuselage bracket and the bolt inserts from the rear....

 

[vic syracuse]

Another one

I had another RV-7A built in 2006 come through my shop this past week for some panel work. Out of curiosity I checked the rear spar bolts and both bolts had fiber nuts on them. When I removed the nut I could see that the bolt was the proper drilled bolt! So, I replaced the fiber nut with the appropriate castellated nut and cotter pin.
This aircraft was built by a "professional" builder for the owner in 2006. From the logs it looks like it has had 9 Condition Inspections, by both the builder and then by others.

Vic