G

grover

Well Known Member
the right landing gear weldment WD821 does not line up as well as it should. it sits higher than it should. some good effort has to be made to get most of the holes in the vicinity of alignment. the only remedy I see is cutting off the front part of the fus. and starting over, paying closer attention to the fit of the longerons (F843?) in that area. thoughts? if alignment requires effort now, it can only be worse come wing-attach time.
 
Whoa! No sudden moves like 'cutting the fus.!

You wrote that the weldment WD821 does not line up as well. Perhaps trying another fitting is in order. Even having a welder close the existing holes,grind flat, and re-drilling might be necessary. Perhaps only a couple of holes are mis-drilled. But first, call Vans! Get their advice.

No sudden hard to overcome moves quite yet though! Sometimes walking away from a problem for a few days will result in an ah-ha moment later.
 
Make Fit

James,

I was able to pin the weldment's inner uppermost hole with a hardware bolt, but the outboard holes were too high. I had to remove (file/sand) some material (about .080, as I recall) from the lower inboard end of the longeron (next to the floor) to get the weldment to "rotate" down. I also removed a little material from the bottom of the weldment's lower support plate (about .025, I think). I coordinated with Van's support - - they were fine with my mods - - no strength worries.

Also, I had to "bang" on the forward support tube to move it upward and inward slightly. This kept it from preventing the downward rotation of the weldment. I had to install shims under the forward and inner support tubes. After a considerable amount of filing, sanding, banging, and some shimming, the weldment fits fine.

Good Luck!

Bill Palmer
 
HOW HIGH?

I had a similar problem if I remember right, it was a long time ago. :)

I had burs and weld seams which were not flat, which kept the weldment too high in relation to the box. Simple matter of grinding bottom surface smooth and flat, then it lined up fine.
 
This is going to sound a little dumb (because it was!). I had the same problem initially. It just wouldn't line up. It did before when I had fit the weldments onto the carry thru bulkhead on the bench before installing it in the jig. The problem turned out to be clecos holding the forward skin to the bulkhead flange not allowing the weldment to fit flush. Also remember that flush mounted rivets on the (bottom) flange have the manufactured head on the inside to allow the the weldment to fit flush. Walking away for awhile is good advise.
 
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advice taken

followed some advice and zapped a note to the home office. they said:

"It's possible for the weldments to take some force to get them in place. There are a number of possible variations in the position of the lower longerons particularly that can make it difficult. In some cases it may be necessary to cut away the horizontal flange of the F-843 to allow the weldment to move low enough. . .So some force may be necessary."

it seems that I and I alone will be the judge of what constitutes "some force." santa brought the finishing kit today, so after the obligatory inventory I'll likely pull the weldment back out and inspect for the aforementioned clecos, not-very-flush flush rivet heads, etc, that may be encumbering this piece.
 
You can open up the holes with a rat-tail file

I've got the new jigless fuselage. I'm not sure how they used to do it, but currently the instructions have you place the weldments on the spar with as many hardware store bolts as you can get in (no nuts). Then you inspect the other holes and mark which way they need to be pulled. After that, you remove the weldment and use a rat-tail file to enlarge the holes in the direction they need to move. Repeat, etc, until all bolts can be installed. This may be more difficult if your spar in already in your fuse, but you should still be able to do it with an inspection mirror.

Guy
 
Force

I seemed to remember two problems. The size/shape of the oval holes was interfering with the weld as it pass through requiring a reshaping of those holes. And remember the old saying. If the weldment doesnt quite fit, dont force it - - - Just get a bigger F@#(*$& hammer!! :) (I needed my big rubber hammer.)
 
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