Steel spar doubler install problems

I received doublers in a bag labeled RETRO 3-074. The bolt holes only align in pairs and only match the spars one position, ie, you can NOT interchange the top pair with the bottom on the spars. OK, I can live with that except these bolts don't match the pre-punched holes in the aluminum bulkhead panels supplied for the fuse. So I see my option is to "massage" the 3/8" holes in the aluminum bulkhead to accept the bolts ??

What did I miss in the instructions ?? The rear doublers in the control stick box will not go in. I can increase the clearance on the seat pan stiffeners to clear the 1/4" steel doubler, but they are too long to install. What am I missing ??

All suggestions appreciated...Larry

The steel wing spar splice plates are normally matched drilled to the #303
front & rear bulkheads - they stay together as a set.
Sounds like your splice plates were matched drilled to some other bulkheads.

I wouldn't ream the holes to make work unless you go to larger bolts.
And if you might, I'd check with Vans first.

mg

Hi Larry

I seem to recall a similar issue, or that the bulkhead pieces were not pre-drilled contrary to the plans / manual (DWGs 6&11, 7-10/11).

It was the first time I had to make "noises" at Vans, and they did agree, and came across some bulkhead pieces that did match - I believe from the company who do the spars?

The steel pieces are lightly engraved with "front and rear", so it is not just not being able to swap top and bottom, but each has a specific location and orientation. Have you tried every combination?

As above, this is the "heart" of the structure, so I would not accept enlarging the fuselage holes to fit.

Your experiences with the center section made me a little bit nervous, so I took the spars, the steel splice-plates and the two F-303 C/D-1predrilled bulkheads, to check for alignment.
All parts have the same number (PP 4 T/ 3-100 L or R, AFT or FWD) engraved. I don't know if the 100 is a general number or if it is the spar-pair of my wing-kit.
By chance the cleco shaft has nearly the same diameter as the bolt holes.
The steel splice plates align in pairs nicely with the bulkheads and the spars.

Can you confirm that this is the situation for the center- section as it should be?




Alignment splice plate to spar


Spar numbers L/R



Bulkhead alignment

Yes, it looks like your good to go..

mg

Doubler alignment confirmation.

pekuba,
What freaked me out to start with was the fact that the bolt spacing on the top plates is not exactly the same as the bottom. When I took the time to get top/bottom/forward and aft all properly oriented on the spars, things looked more promising. however, installing the wings in the fuse bulkhead with standard aircraft bolts for pilots was a squeeker ! If you have spars (not complete wings, it would be wise to assemble the spars/bulkhead pieces and doublers when you rivet the fuse pieces together. I did not have that option because I am using wings from a wrecked RV-3B and bought kits for everything else. Hope this helps.

Hi Larry

If you have spars (not complete wings, it would be wise to assemble the spars/bulkhead pieces and doublers when you rivet the fuse pieces together

Click to expand...

Suggest good advice, and example shown below (from http://www.vansairforce.com/community/showpost.php?p=422389&postcount=55 ):

Larry and Andy,
I'm getting more and more confused about how to proceed with my build.
Initially I thought it's ok to check if the splice plates and the predrilled bulkhead pieces align with the predrilled spars. That seems to be ok in my case.

According to Andy's Photo it seems that you prepared and drilled and primed the whole center section with the fuselage parts before you started the wing construction (did you also fit the close tolerance bolts?) ?
So, do I have to study and understand the whole fuselage construction before starting the wings?

Thank you very much for your advice since I'm building in a builder desert, nobody has ever built a -3 here, and if there's a builder he's building a prepunched kit, so the only support for me is via vansairforce.

Peter

Prefab spar bulk head

Pekanbaru,
Andy has the experience here, but your question gave me an idea. The goal is to secure the aluminum bulkhead pieces in alignment withe spar and doubler holes. And keep it that way during fuse build. Consider riveting as much as possible like Andy's pic, then install a wood spacer in place of the spars with close tolerance bolts and doublers during fuse fab.

This will assure proper clearance of seat formers and floor stiffeners fore and aft of the spar assembly also.

Hi Peter

Initially I thought it's ok to check if the splice plates and the predrilled bulkhead pieces align with the predrilled spars

Click to expand...

There is no rule book here... nobody can tell you how best to do it, you have to make the judgement Vans have not got a clue about building an RV-3, and each builder on here will, I suspect, have had a different experience.

I had to secure additional parts from Vans, supposedly match drilled to something, "found" at a different facility. It was relatively quick work to put together the centre section, then assure myself that the wing spars, splice plates and bolts all went together. The centre section complete is very rigid, so none of these elements are likely to change shape during build.

There would be little more depressing than trying to install the wing bolts after 5 years of work to find the holes do not line up You build the whole fuselage about that centre section, so I can only suggest you do the same for piece of mind.

it seems that you prepared and drilled and primed the whole center section with the fuselage parts before you started the wing construction (did you also fit the close tolerance bolts?) ?

Click to expand...

I did, because the centre section is really part if the wing kit. However, I doubt you are going to get new wing spars if there is a problem, but solve the fuselage centre section parts.

Thank you very much for your advice since I'm building in a builder desert, nobody has ever built a -3 here, and if there's a builder he's building a prepunched kit, so the only support for me is via vansairforce.

Click to expand...

Exactly - a great facility

then install a wood spacer in place of the spars with close tolerance bolts and doublers during fuse fab.

Click to expand...

Absolutely... I think I had the RV-8 QB kit wood blocks to use? There will be a similar exercise to get the rear spar distance the same in the fuselage as the wings...

Thank you very much guys.
Before continueing the wing construction I'll study the fuselage construction thoroughly, pick the fuselage bulkheads and all the necessary parts. Then, I'm sure, I'll be back with some questions, probably . But the close tolerance bolts; from other builders I heard stories, freezing these with liquid nitrogen, and heating the spar with the heat gun, is the best way ( the only?) to mount the bolts. It's probably a good way, but will I be able to remove these bolts again without force.
OK. First I'll have a look at the parts and the assembly.

Thanks again,

Peter

But the close tolerance bolts; from other builders I heard stories, freezing these with liquid nitrogen, and heating the spar with the heat gun, is the best way ( the only?) to mount the bolts. It's probably a good way, but will I be able to remove these bolts again without force

Click to expand...

You may need those techniques as a last resort. But both RV-8 and RV-3, some oil on the bolts, and a light tap with a soft hammer and they go in/out fine

Everything is fine now. Finally I understood how the pieces go together. I didn't expect the desription of the center section in the wing manual (7-11). Initially searched in the fuselage section. Simply didn't read ahead enough.
Maybe one should build a -3 from cardboard templates first .
Also found in the archives a description with very helpful fotos from Paul Dye.
http://www.vansairforce.com/community/showthread.php?t=50711
Thanks again to all involved.
Peter