Gear Weldments

[koda2]

I thought once I got past the damage caused by the first builder and then fixing the mistakes I had made, the rest of my early 6AQB would go together a whole lot easier. But not so. I have spent a considerable amount of time and expense in the last 12 months dealing with the unsatisfactory work from the factory.

My latest discovery is that the main gear weldments don't fit.

At first I thought it was my ineptitude in putting things together, but putting the wings on the bench and trying to match a weldment to a a spar showed that almost none of the "match-drilled" holes match the spar much less the fuselage holes. Some of the holes are considerably off. Here's one side:

The weldments don't match the gear legs either. Here is the right gear leg top showing that the hole drilled is not the same.

My only conclusion is that the weldments were mixed up somehow when the kit was first shipped years ago and I got somebody else's weldments. Or else my weldments were just drilled on a factory jig somewhere, hoping they'd fit.

I have tried to recreate the geometry to see just how far off all the holes are when the landing gear is installed but so far I can't quite get the legs quite where they should be under the plane. I will probably have to enlarge the holes in the floor skin some more.

If I can get the parts to line up, I may be able to take the gear weldments and weld the 50 or so holes shut and re-drill and re-ream them. At least some of the re-drilling will have to be done with the plane upright and both assemblies clamped to the spar.

Has anybody done this? Is it advisable?

My only other good option is to buy all new weldments and gear legs. Vans has a set of legs and weldments that are supposedly match-drilled to each other. No guarantee that they will fit but at least the weldments will be a clean slate.

Has anybody else dealt with this?

Dave A.

 

[WingsOnWheels]

I haven't seen mention of this particular issue before. I would agree that you likely received the wrong weldments with the QB fuse. I would give Vans a call and see what they say. Even if the kit is second-hand, they might know of a solution or be willing to send replacements.

I just received my -6 fuslage kit a couple weeks ago. The new kits do come with the gear leg and weldment match-drilled together.

 

[JonJay]

Give Russ a call.

http://http://mccutcheonmetalfabricationaviation.com/
He builds the weldments for Vans. He can probably help.

 

[Bob Hoffman]

Dave,
Looking at picture #3 in lining the landing gear to each other you clamped each to a long piece of angle iron (which I also did) but I notice that you appear to have a spacer under the threads (which I didn't do) resulting in a toe out.Did I miss something in my process ? If I did how important is it ?
How much of a spacer is it ?
Bob

 

[LarryT]

Toe-in?

or am I looking at the photograph wrong?

LarryT

Dave,
Looking at picture #3 in lining the landing gear to each other you clamped each to a long piece of angle iron (which I also did) but I notice that you appear to have a spacer under the threads (which I didn't do) resulting in a toe out.Did I miss something in my process ? If I did how important is it ?
How much of a spacer is it ?
Bob

 

[flion]

It's toe-in, and the plans said you could use a penny there. Literally the cheapest shims I ever used ...

 

[az_gila]

How old are...

...the weldments?

The early ones that came from Vans were not drilled with any of the AN3 holes. All of the hole were match drilled to the spar, and then the 6 or so AN4 holes were created by enlarging the specific AN3 holes.

Could your weldment be an early one that was customer drilled to the spar? Perhaps even a different spar?
The early weldments were also not Vans powder coated (no finish on them), but some did come with the gear leg match drilled to the weldment.

Since your gear leg match drilling is off, I wonder if you got a mix of different era parts?

 

[noelf]

I am sort of confused...

...with the first picture. It looks like the aircraft is upside down, and the gear weldments are right side up. I am looking at the preview plans Sheet 59, top of the spar cary-through is straight. Your photo could be misleading??

Also, I did not see the F-604B (L&R) that should have been riveted onto the F-604C spar cary-through.

On my -6A slow build, there is a single AN5-21A bolt that locates the gear leg into the gear leg weldment. That bolt is located towards the top of the weldment. My gear leg and weldment were "Van's aligned and drilled" in their shop fixture, so I had no issues aligning the leg to the weldment bolt hole. I did have to align and drill the weldments to the rest of the aircraft.

 

[az_gila]

The pic is of...

...with the first picture. It looks like the aircraft is upside down, and the gear weldments are right side up. I am looking at the preview plans Sheet 59, top of the spar cary-through is straight. Your photo could be misleading??
......

...the weldment held against the wing spar stub. The wing is upside down on saw horses, I presume. No fuselage parts in the first pic.

Took me a while to work this out too...

 

[noelf]

Thanks Gil...

...now I see it. So, in the picture, if the wing is upside down, and the gear weldment is right side up, then I guess I would expect the holes to NOT align...

 

[Russ McCutcheon]

We have not built these parts for years, mid 90s, in any case we never drilled/drill any holes in anything that matches to the airframe or the gear legs, they where drilled buy Van?s or a previous builder.

Welding the holes could pose a problem, the weld tends to be harder then the drill.

 

[az_gila]

I think that is the case...

...now I see it. So, in the picture, if the wing is upside down, and the gear weldment is right side up, then I guess I would expect the holes to NOT align...

The wing appears to be upside down looking at the angle of the rivets of the vertical internal stiffeners in the spar web.

Since the other picture is correct, perhaps the wrong side weldment was held up for photo purposes in pic #1...

UPDATE -

I checked sheet 13 of the plans carefully, I think the wing is actually correct side up. The holes for the spar bolts are not spaced at the same distance top and bottom, making the stiffeners appear tilted.

Pic 1 is of the spar stub but the wing is correct side up. Ignore above portion...

 

[koda2]

gear alignment

Sorry for the delay in answering the questions posed.
I have been busy stripping the weldments(ugh!) and today I drove them 150 miles so a fellow builder could TIG the holes shut so I can re-drill them.

The weldments (as far as I know) came with the 1996QB kit. The kit even has the original Van's built spar (not Phlogiston?). The weldments came rough red primed so I had them powder coated. I had no idea they wouldn't match the spar.

The pictures are all right side up. I positioned the plane up on tall supports to mount the weldments, gearlegs, wheels, pants etc. for the first fitting. When the weldments wouldn't fit fit, I took the wings back off and tried to see why the bolts wouldn't fit. It then became obvious that the weldments weren't the right ones.

To see if I could salvage the weldments, I put the wings back on and tried to recreate the positioning of the landing gear and weldments as the slow build 6 plans show, only here the plane is right side up. In the early slow builds all the holes were drilled by the builder but on the QBs the weldments were supposedly match drilled at the factory as the fuselage was being built.

In the last picture the gear legs are clamped to a long angle per plans with a 1/16th spacer for toe-in and 12/16s spacer under the heel for correct alignment. Once the whole assemblage is in correct position under the plane, the gear weldments were clamped to the spar. Of course, the holes still don't line up, but this is how I will have to match the landing gear to the plane. Apparently, at least one other builder has done this, so it can be done.

After removing the powdercoating I discovered several things. One, the weldments are extremely well made and the original welds are a work of art.
Two, there was some rust forming under the powdercoat and it looked just like filliform corrosion seen on aluminum parts. Three, the part numbers on the weldments were unusual, one side was 852 and the other 827. I can't find these on the current Van's list, so they must be an eariler designation.

I am hoping I can re-drill the holes, so the weldments will be matched to the spar, the fuselage, and the gear legs.
Dave A.

 

[az_gila]

The plans show...

.... Three, the part numbers on the weldments were unusual, one side was 852 and the other 827. I can't find these on the current Van's list, so they must be an eariler designation.
.....

...these as part number Wd-626.

Could the 852 and 827 numbers be connected with the match drilling?

Does your spar have either of these numbers?

 

[koda2]

Numbers

The spars are correctly labeled right down to the laminations which have the original plane serial number. The gear legs are numbered with the correct part number engraved on the end.

I couldn't find any other numbers on the weldments so I don't know where they came from or where they were intended. They are obviously made for an -A model and in 1996, the 6 was it.

Perhaps the engraved numbers on the weldments belong to the manufacturer that Vans used at the time.
Dave A.

 

[koda2]

Weldments-rust

Powdercoating has its own problems. Any break in the powdercoating allows moisture to get underneath and start rust without disrupting the paint coat so it is not apparent. Poor preparation can do the same.

I powdercoated my weldments several years ago, since they came primed. The shop had to sandblast or strip the primer to get to bare metal so the paint powder would stick to it. Either the conditions weren't right or the prep wasn't right cause rust was beginning.

Even steel can show "filiform corrosion"

I may just prime and paint this time.

Dave A.
6A

 

[Bob Hoffman]

Ok! I need to reopen this thread to make shure I have this right.
I am rebuilding a RV6A and I had to replace the landing gears which came undrilled (early kit) ,I aligned the gears by clamping the legs to a long angle iron bar ,marked everything ,pulled the gears and weldments out ,stripped (now that was a job) weldments for new powder coating, when I read here that a "toe in" factor is needed by placing a "penny" between the angle bar and the threaded end of the landing gear.
So last evening I bolted the weldments and gear legs back in to allow for this adjustment,but I can't find this in any of my plans or instructions.
So before I really screw things up can someone tell me what I need to do so that I can do it right the first(or is it second?) time.
Thanks

 

[koda2]

gear legs

Bob,
Depends on your time factor, if you want I can xerox and send you the illustrations from the plans that I have. I don't have a way to digitally scan them anymore. Send me a PM if you want them.

Dave A.

 

[Bob Hoffman]

Dave,
Sent you a P.M.
Thanks
Bob

 

[noelf]

Your "penny" idea is quite clever...

...now you get to look in several areas of the construction book. For my -6A, it is Section 8, FITTING THE RV-6A LANDING GEAR MOUNTS, paragraphs 4, 5, and 6.

Paragraph 6, points you to figure 8-7 (in the back of Section 8) which shows a rough sketch of the alignment detail. Also look at figures 8-8 and 8-9.

You are also directed to Drawing 59 for this work.

Good Luck with the gear attach...

 

[koda2]

instructions

Bob,
The instructions that I have, including Drawing 59, a sketch of the alignment callouts, and pictures of a slow build process, have been sent.
Dave A.

 

[Bob Hoffman]

Dave,
Received everything - very helpful.
Small world, I see by the post mark that your from Abilene Tx.
I was based in Abilene @ the AF base there in 1959 - 1960 had a great time while there. I was a Northerner just out of High School, it was my first exposure to Southern Hospitality, it was nice.
Tell me is the town still a "dry" town ?
Thanks for your help
Bob