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-   -   Check those AFT Spar bolts (https://vansairforce.net/community/showthread.php?t=143315)

vic syracuse 11-01-2016 12:20 PM

Check those AFT Spar bolts
 
It seems that about 40%-50% of the RVs on which I perform CI's or prebuys have the wrong bolt/nut combination on the aft spar. The aft spar actually has some movement on it during flight loads, and can move. Therefore it requires a drilled bolt, castellated nut, and cotter key. Most of the ones I see have a fiber locking nut on them. Some even have the fiber nut on the drilled bolt!

I'd post a picture but I think it is pretty self-explanatory. Most of the RV's can be checked with a flashlight by crawling underneath and looking past the flap. It is also very easy to remove the last two screws on the wing root fairing and peel it back to inspect.

Vic

LettersFromFlyoverCountry 11-01-2016 12:38 PM

Just to clarify, you're talking about the bolt connecting the spar to the fuselage "fork"?

vic syracuse 11-01-2016 02:32 PM

Quote:

Originally Posted by LettersFromFlyoverCountry (Post 1123462)
Just to clarify, you're talking about the bolt connecting the spar to the fuselage "fork"?

Yes.

Vic

Steve Melton 11-01-2016 03:09 PM

and if they are not drilled perfectly square put a set of spherical washers on them.

6 Gun 11-01-2016 06:09 PM

Nuts
 
Mine has fiber nuts with torque seal no movement.Will watch.
Bob

wirejock 11-01-2016 07:14 PM

Plans
 
Quote:

Originally Posted by vic syracuse (Post 1123458)
It seems that about 40%-50% of the RVs on which I perform CI's or prebuys have the wrong bolt/nut combination on the aft spar. The aft spar actually has some movement on it during flight loads, and can move. Therefore it requires a drilled bolt, castellated nut, and cotter key. Most of the ones I see have a fiber locking nut on them. Some even have the fiber nut on the drilled bolt!

I'd post a picture but I think it is pretty self-explanatory. Most of the RV's can be checked with a flashlight by crawling underneath and looking past the flap. It is also very easy to remove the last two screws on the wing root fairing and peel it back to inspect.

Vic

My 7a plans clearly show bolt, washer, nut and cotter pin.

YellowJacket RV9 11-01-2016 08:00 PM

Quote:

Originally Posted by wirejock (Post 1123554)
My 7a plans clearly show bolt, washer, nut and cotter pin.

I think the plans have always had it, but my guess is that a lot of people get to that point in the build, and have gained enough confidence that they stop consulting the plans for a lot of things...I know I caught a few mistakes of my own after going back and looking at the plans that I had earlier just skimmed over.

Chris

RV7A Flyer 11-01-2016 09:21 PM

Quote:

my guess is that a lot of people get to that point in the build, and have gained enough confidence that they stop consulting the plans for a lot of things
This may sound like OCD, or maybe it's just a side effect of the rigorous engineering we do at work, but...

Prior to the DAR inspection, I photocopied all of the preview plans, and then went over them and verified that each and every item on every page, including each of the detailed drawing, hardware callouts, etc., had been done IAW the plans (or there was a very good reason for a variance), checking off on paper every item.

If I missed anything, it wasn't for lack of trying to verify every item! :)

vic syracuse 11-02-2016 06:06 AM

Quote:

Originally Posted by 6 Gun (Post 1123538)
Mine has fiber nuts with torque seal no movement.Will watch.
Bob


Why wouldn't you replace it with the correct combination? Takes about 10 minutes per side.

Vic

Bob Martin 11-02-2016 06:35 AM

Thanks
 
Thanks for the Tip...or Heads Up VIC!
It was a pleasure to meet you in LKU for the RV-7 pre-buy!
I learned things from your visit!
Look forward to seeing you at a fly-in.

BenNabors 11-02-2016 08:24 AM

Electronic drawings show a fiber insert nut, no?
 
Quote:

Originally Posted by vic syracuse (Post 1123458)
Therefore it requires a drilled bolt, castellated nut, and cotter key. Most of the ones I see have a fiber locking nut on them. Some even have the fiber nut on the drilled bolt!
Vic

Did this last night. Looking at the electronic drawing file:
Drawing 20, area F-1 shows:
AN3-10A bolt
AN960-10 Washer
AN365-1032

Is not an AN365-1032 have a fiber insert?

BoilermakerRV 11-02-2016 08:48 AM

Quote:

Originally Posted by BenNabors (Post 1123662)
Did this last night. Looking at the electronic drawing file:
Drawing 20, area F-1 shows:
AN3-10A bolt
AN960-10 Washer
AN365-1032

Is not an AN365-1032 have a fiber insert?

That is just part of the F-705 bulkhead assembly. The discussion is regarding the actual wing rear spar attachment. See Drawing 38, Section H-H, Zone A4.

Lemmingman 11-02-2016 08:55 AM

Hey Ben,
Check out #38 section H-H. The bolt that he's referring to is the one that connects the rear spar of the wing to the fuselage.

JonJay 11-02-2016 10:22 AM

At least on the vintage for my 6, the bag contents for this hardware was an AN365 and A bolt. That is what the factory provided. They didn't provide a drilled bolt. This might explain why so many are this way.
What is in the current kits inventory sheet for this bolt? Do they supply the correct bolt and nut?

I check mine at each CI, and while it makes sense that this bolt can move, mine has always remained torqued. So, each time I get there in my CI, with full intent of changing it out, I check it and move on.
I am not arguing this shouldn't be a drilled and safety'd assembly, but, the factory didn't seem to care at the time.

I think this falls into the category of "good practice", rather than a true safety concern. I have never heard of any issues related to using a nyloc here, but I am not saying it isn't a good idea, and it is what the plans show.

sbal0906 11-02-2016 10:29 AM

And we're not just talking about the -7/7A, right? So, on the -9/9A, on drawing 38 Section G-G, it lists:

AN5-10 Bolt
3x AN960-516 Washer
AN310-5 Nut
MS24665-208 Cotter Pin

These attach the W-907 Rear spar assembly to the F-705 bulkhead assembly.

Cheers,

JonJay 11-02-2016 10:32 AM

Quote:

Originally Posted by sbal0906 (Post 1123693)
And we're not just talking about the -7/7A, right? So, on the -9/9A, on drawing 38 Section G-G, it lists:

AN5-10 Bolt
3x AN960-516 Washer
AN310-5 Nut
MS24665-208 Cotter Pin

These attach the W-907 Rear spar assembly to the F-705 bulkhead assembly.

Cheers,

Yes, but what does Van's supply you with? I am curious.

Raymo 11-02-2016 10:35 AM

Quote:

Originally Posted by JonJay (Post 1123695)
Yes, but what does Van's supply you with? I am curious.

I am the second owner of my kit but I found exactly two of the aforementioned bolts in the parts bins that came with it.

sbal0906 11-02-2016 10:45 AM

Quote:

Originally Posted by JonJay (Post 1123695)
Yes, but what does Van's supply you with? I am curious.

Are they supplied with the wing kit or the fuselage kit? If it's the wing kit, I'll have to check when I get home. I don't have the fuse kit yet. I did do the inventory for the wing kit so if those parts are listed in the inventory list then I can say they are included.

JonJay 11-02-2016 10:50 AM

Quote:

Originally Posted by sbal0906 (Post 1123700)
Are they supplied with the wing kit or the fuselage kit? If it's the wing kit, I'll have to check when I get home. I don't have the fuse kit yet. I did do the inventory for the wing kit so if those parts are listed in the inventory list then I can say they are included.

Thanks, but I am not saying Van's didn't include the parts. Did they include the correct parts?
I do not know what kit they supplied them in. Perhaps someone currently at this stage can comment.
If Van's has continued to supply the "wrong" hardware, or different than the plans, what Vic is seeing would have a common thread.

( typing while someone was answering. Good to know they supplied the correct hardware with that kit - Thanks Raymo! )

az_gila 11-02-2016 11:28 AM

Always a drilled bolt for the -6
 
Quote:

Originally Posted by JonJay (Post 1123692)
At least on the vintage for my 6, the bag contents for this hardware was an AN365 and A bolt. That is what the factory provided. They didn't provide a drilled bolt. This might explain why so many are this way.
What is in the current kits inventory sheet for this bolt? Do they supply the correct bolt and nut?

......

That may be what they provided, but the -6 plans on sheet 46 have always specified a drilled bolt.

The early plans called for a AN5-7 bolt, AN310-5 nut and a AN960-519 washer.

A later edit in 1997 changed it to a AN5-10 bolt and added the cotter pin.

In 2001 the number of washers call out was increased to 3.

A drilled bolt has always been specified for that location on the -6.

JonJay 11-02-2016 11:44 AM

Quote:

Originally Posted by az_gila (Post 1123712)
That may be what they provided, but the -6 plans on sheet 46 have always specified a drilled bolt.

The early plans called for a AN5-7 bolt, AN310-5 nut and a AN960-519 washer.

A later edit in 1997 changed it to a AN5-10 bolt and added the cotter pin.

In 2001 the number of washers call out was increased to 3.

A drilled bolt has always been specified for that location on the -6.

.... I said that Gil. But if they kept supplying the wrong hardware, in the right bag, it makes sense why Vic see's so many of these installed. I have a hard time believing that so many would simply substitute without a reason if the right hardware was in the kit. Assumptions would be made....
It was a long time ago, but I questioned the factory on this. Since it was a long time ago, and said person no longer there, I will just let rest what they told me. It is a simple thing to follow the plans and no reason not too. Thanks to Vic for his post.
Moving on now.....

Fearless 11-02-2016 12:06 PM

Bolt orientation
 
My DAR questioned the orientation of the bolt but I showed him in the plans how Van's had it oriented.

az_gila 11-02-2016 01:03 PM

Quote:

Originally Posted by JonJay (Post 1123718)
.... I said that Gil. But if they kept supplying the wrong hardware, in the right bag, it makes sense why Vic see's so many of these installed. I have a hard time believing that so many would simply substitute without a reason if the right hardware was in the kit. Assumptions would be made....
It was a long time ago, but I questioned the factory on this. Since it was a long time ago, and said person no longer there, I will just let rest what they told me. It is a simple thing to follow the plans and no reason not too. Thanks to Vic for his post.
Moving on now.....

The -6 hardware provided was frequently of the wrong length. Even the bolt in question had it's length changed in a revision...:)

I dumped all of my kit hardware in trays and just picked what fit, using the plans to specify the type of hardware. Putting the wrong hardware in without checking the plans is a big boo-boo. :rolleyes:

If original -6 builders simply went by bag labels there will be many bolts too short...:)

az_gila 11-02-2016 01:05 PM

Quote:

Originally Posted by Fearless (Post 1123724)
My DAR questioned the orientation of the bolt but I showed him in the plans how Van's had it oriented.

Why would he question it? The bolt is in "standard orientation" with the head forward.

JonJay 11-02-2016 01:41 PM

Quote:

Originally Posted by az_gila (Post 1123733)
The -6 hardware provided was frequently of the wrong length. Even the bolt in question had it's length changed in a revision...:)

I dumped all of my kit hardware in trays and just picked what fit, using the plans to specify the type of hardware. Putting the wrong hardware in without checking the plans is a big boo-boo. :rolleyes:

If original -6 builders simply went by bag labels there will be many bolts too short...:)

Too long, too short, absolutely agree. Also, substitutions where made in the early days. Some of those substitutions where hardware.

If you found the wrong hardware, and called the factory, and they told you it was fine.... just sayin...., Is that still a big boo-boo? :rolleyes: hmmmm..... maybe.

I love a mystery, and again, there is a reason Vic is finding this a common place that the hardware doesn't match plans and it isn't by chance.

az_gila 11-02-2016 03:55 PM

Quote:

Originally Posted by JonJay (Post 1123742)
....
I love a mystery, and again, there is a reason Vic is finding this a common place that the hardware doesn't match plans and it isn't by chance.

Yes, it's a mystery...:)

But I think it's because early -6 builders somewhat gave up on the plans by the time the wings got attached and simply used "standard" hardware without looking at the plans to see if a specific locations called for "special/different" hardware..

Did anyone really check bags of hardware that far along in the build process..:)

JonJay 11-02-2016 04:15 PM

Quote:

Originally Posted by az_gila (Post 1123774)
Yes, it's a mystery...:)

But I think it's because early -6 builders somewhat gave up on the plans by the time the wings got attached and simply used "standard" hardware without looking at the plans to see if a specific locations called for "special/different" hardware..

Did anyone really check bags of hardware that far along in the build process..:)

Of course we didn't read the plans. We needed them to start fires in our caves.

rvbuilder2002 11-02-2016 04:46 PM

The bolt specified in the plans for all RV kits is an AN5 with a castellated nut and cotter pin.

AN5 bolts are only used in a few places in an RV. The rear spar attach and the landing gear legs are the only ones I can think of right now so short AN5A bolts would have never been intentionally supplied.

The RV-6A I completed in 1993 was supplied with castellated nuts and drilled AN5 bolts and they were called out in the plans.

All new designs since the RV-6 have specified and supplied the same bolt (I think it is in the finish kit hardware).

JonJay 11-02-2016 05:18 PM

Quote:

Originally Posted by rvbuilder2002;
....short AN5A bolts would have never been intentionally supplied.

I believe you Scot, and was hopeful you would chime in.
I am still dumbfounded why so many keep showing up, and I know what was supplied to me.... Others would have to intentionally order the wrong hardware as AN5A's typically aren't just laying around. Why would someone do that?
No matter. If my kit was the only one in the fleet, others are just being careless.

I didn't mean to derail Vic's safety post. It does'nt matter why the wrong hardware is being used.

vic syracuse 11-02-2016 06:10 PM

Not a shipment issue
 
OK, sorry, been busy all day and haven't had time to check this. The bolts are supposed to be drilled and castellated. Just yesterday I removed 2 more from the AFT spar in an RV-8 and they WERE drilled bolts(AN5) but yet had fiber nuts on them. I see many that way.
My guess is that at the airport when final assembly occurs, everyone forgets that it is supposed to be castellated and doesn't check because the plans are left at home.

And I hear you on "they haven't moved so I leave them," but I don't think that is the right approach. My opinion. :)

Vic

JonJay 11-02-2016 06:30 PM

Quote:

Originally Posted by vic syracuse (Post 1123812)
And I hear you on "they haven't moved so I leave them," but I don't think that is the right approach. My opinion. :)
Vic

Your right Vic. Not just an opinion. Good practice is just that.

Again, thanks for posting all the safety items you discover in the many RV's you inspect.

rightrudder 11-02-2016 11:41 PM

Quote:

Originally Posted by az_gila (Post 1123733)

I dumped all of my kit hardware in trays and just picked what fit, using the plans to specify the type of hardware. Putting the wrong hardware in without checking the plans is a big boo-boo. :rolleyes:

I did the same, and if I couldn't find the hardware specified on the plans, I put in a quick order to ACS. The rear spar/fuselage junction is supposed to allow for a small amount of rotation...so don't torque it down!

Fearless 11-03-2016 06:36 AM

Quote:

Originally Posted by az_gila (Post 1123734)
Why would he question it? The bolt is in "standard orientation" with the head forward.

Gil,

That's just it - on the 9/9A plans for DWG 38 Section G-G the bolt head is aft - this may be due to flap clearance. I can't find a revision on Van's site telling me the orientation should be otherwise.

6 Gun 11-03-2016 07:19 AM

Bolts
 
Getting ready to change mine on my RV6.
Should they be torqued to proper numbers or snug the plans show the correct way to install bolt?Im pretty sure from the torq seal I have in place there is no movement going on .
Bob

JonJay 11-03-2016 08:00 AM

Quote:

Originally Posted by 6 Gun (Post 1123909)
Getting ready to change mine on my RV6.
Should they be torqued to proper numbers or snug the plans show the correct way to install bolt?Im pretty sure from the torq seal I have in place there is no movement going on .
Bob

Yes. However, with any castellated nut, you have to get lucky that you can get the cotter key in at a precise torque value. You can experiment with combinations of standard and -L washers. Get it close.
I don't know what the plans show, but on the 6 you can easily put the bolt in the proper orientation.

I don't think there is much if any movement at this joint, but per plans is the proper way to do this and kind of a standard for rear spar connections in other airplanes I have seen. Van was an excellent engineer and he would have done it the way he deemed best regardless.

rvbuilder2002 11-03-2016 09:22 AM

Quote:

Originally Posted by Fearless (Post 1123896)
Gil,

That's just it - on the 9/9A plans for DWG 38 Section G-G the bolt head is aft - this may be due to flap clearance. I can't find a revision on Van's site telling me the orientation should be otherwise.

In AC43.13 where "standard" fastener orientation is addressed, it also adds "unless specified otherwise by the manufacturer". There are numerous instances in RV's where a deviation from the standard is recommended.

Having said that, in this particular case I am not sure why the bolts are specified to be reversed because there would be no interference if the nut was on the aft side. It is possible that it is because of a late design change in the flap leading edge but I don't recall one. So in the case of the RV-9 it would be acceptable to install the bolt in the normal orientation.




Regarding movement of this joint and people seeing no evidence of it.......

It all depends on the loads the wing has experienced!

I assure you that if the wings are loaded to limit load values, there is significant flex/deflection in the wings (witnessed during many different static load tests) which translates to some amount of movement at the aft spar attach point.

JonJay 11-03-2016 09:56 AM

Quote:

Originally Posted by rvbuilder2002 (Post 1123939)
Regarding movement of this joint and people seeing no evidence of it.......

It all depends on the loads the wing has experienced!

I assure you that if the wings are loaded to limit load values, there is significant flex/deflection in the wings (witnessed during many different static load tests) which translates to some amount of movement at the aft spar attach point.

Very good point Scott.
This also leads into checking the screws of the overlap of the fuselage bottom skin to the wing. I have found these need to be tightened up a bit over time. I think many do not think to check them.

az_gila 11-03-2016 10:20 AM

Torque it up a bit more...
 
Quote:

Originally Posted by JonJay (Post 1123921)
Yes. However, with any castellated nut, you have to get lucky that you can get the cotter key in at a precise torque value. You can experiment with combinations of standard and -L washers. Get it close.
I don't know what the plans show, but on the 6 you can easily put the bolt in the proper orientation.

......

AC43.13 allows quite a spread of torque allowance to get the cotter pin holes to line up.

While a AN5 bolt is usually listed at 100-140 in lbs, the torque can be increased to the maximum if needed to get the alignment, which is 225 in lbs.

As usual, add the "drag torque" to the above numbers, but this is pretty minimal for a non-locking nut.

f. When installing a castle nut, start
alignment with the cotter pin hole at the minimum
recommended torque plus friction drag
torque.
NOTE: Do not exceed the maximum
torque plus the friction drag. If the
hole and nut castellation do not align,
change washer or nut and try again.
Exceeding the maximum recommended
torque is not recommended.


https://www.faa.gov/documentLibrary/...Chapter_07.pdf

BoilermakerRV 11-03-2016 10:46 AM

Quote:

Originally Posted by az_gila (Post 1123955)
AC43.13 allows quite a spread of torque allowance to get the cotter pin holes to line up.

Great addition Gill! Thanks.

Steve Melton 11-03-2016 10:56 AM

this bolt acts as pin. if you apply torque to the nut to apply a clamp load and the joint moves it will fret and then it will lose the clamp load over time. I snugged mine up hand tight.


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