HELP! RV-7 tailspring doesn't fit in the mount!

Hi gang.

Today, it was time to install the FSTS 635-1 tailspring into the WD 409 tailspring mount. It looked like an easy task, but it turned out to be the opposite...

Here, the tailspring is in place:







The bolt going through the mount and the spring didn't want go in all the way and here's why:





Here's a closer look. The holes in the mount and spring doesn't match at all. It's about 2-3 mm error beetween the two holes.



(The "golden spot" in the hole is the bottom of the bolt.)

We turned the spring 180* but that result wasn't any better.



We took the spring out again, leveled it in a wise and drew the centerline of the spring:






It looked like the hole is not drilled in the center of the spring, and here's a closer look to verify:



It's obvious that the hole is not drilled in the center of the spring.

We checked the hole in the mount in the fuse and love and behold: that hole is 100% correct drilled! Phew!



It seems to me that the pre-drilled hole in the tailspring is the cause of the hole mess. Since it's drilled off-center through the spring, it won't match up with the lower hole in the mount.




Here's the big questions: has any of you had the same problem? And what to do next?

Obvioussly I'll contact Vans but they probably won't reply until Monday, so in the meanwhile, it'll be interesting to hear what you guys say?

To me, the only sollution appears to be to get a new spring with the correct drilled hole?

Yep. I agree. The spring is drilled incorrectly. I suspect Vans will remedy the situation but it will have to wait til Tuesday. Monday is Memorial Day here in the US.

Mine Too!!!

Yep, mine is that way too. It wears the tire on that side. I flip it over every 25 hours, at oil changes.

At JD Air, we had a tailwheel yoke that was mis-drilled. It correct that alignment on the other end.

I can tell you with 700+ hours it does not cause any steering issues.

Mine is kind of like that but not as bad. Thing is I drilled mine. It hasn't really been a problem.

Thanks for the input guys.

Since there's no way to install the bolt, this problem has to be dealt with one way or another.

I'll send Vans an e-mail with some pics and hear what they have to say.
I'll post an update here later on.

We have many tailwheel replacement parts, if needed.

The least expensive repair option might be an undrilled mounting socket. That would fix the problem, and the shipping to Norway would be relatively reasonable.

mounting socket

The problem is the misdrilled holes

Thanks for the feedback guys, but I think some of you have misunderstood me, probably because my bad english writing.

The problem is that the predrilled holes in the bracket and the spring doesn't match, this preventing the bolt to be inserted fully. It goes only halfway.

Here you can just spot the top of the bolt in question:





Here is a closeup of the bolt, and as you can see, the bolt is only going in halfway before it jams.





I've sent Vans an e-mail about this and I'll post an update when they reply.

Is this a QB fuselage kit?

Just a guess, but I suspect that the spring gets match-drilled to the mount during manufacturing, to ensure that the two fit each other precisely. Since yours don't fit each other, I'm going to further guess that there was a mix-up during manufacture, and somebody else got the spring that was supposed to go with your mount.

I guess there is another possibility, that they inserted the spring into the mount the wrong way when drilling it.

Either way, I'm looking forward to the update on this issue from Vans.

Thanks, Bob K.

The fault was entirely ours....

Hi gang.

Here's an update on the above because the problem is solved now, and that is thanks to Gus at Vans.

When I had described the problem and sent him some pics to him in an e-mail, he responded back with a sollution we hadn't thought about: he asked if there was any chance that we somehow might have mixed up the two tailsprings to my two -7's.

Dang! That suggestion was something we never had thought about....

A few days ago, I swapped the two springs and both of them went right into their new homes! a BIG relief!

And better still: both tailwheels are now vertical (no tilt)

What is strange, is that the spring we have been using in Wilco, (my flying -7) fitted in Kermit (The -7 we are building now), meaning that this spring fits in BOTH planes.

The spring which we had tried to fit in Kermit, didn't fit there but it fitted in Wilco! (meaning that spring fitted ONLY in one plane)

Very strange.... but what the heck; both springs are now where they schould be so everything is fine.

I'm impressed with Gus, because he remembered that I have two -7's.
I mean; I guess he's in contact with 1000's of customers all over the world, and still he came to think of the fact that I have two -7's... GOOD JOB GUS!!!

So I guess it's proven once again: these kits from Vans are really a piece of art! It all fits together nicely, as long as the builder doesn't screw up....

Thanks for that update! I have been wondering how this would turn out.

Earlier, I wrote:

Bob Kuykendall said:

...I'm going to further guess that there was a mix-up during manufacture...

Click to expand...

Well, I was right that there was a mix-up, but I was wrong about it being during manufacture.

Bob Kuykendall said:

...and somebody else got the spring that was supposed to go with your mount...

Click to expand...

It turns out that that someone else was you!

Thanks, Bob K.