How to Cut into Vector Bellcrank

[Peter in Fairfax, VA]

What incision is the best approach to the bellcrank's leadouts for a Vector ARF?

The older Brodak ARFs have an issue with leadouts breaking, primarily at the bellcrank.  You can tell the troublesome ones by looking for silver crimp sleeves with two swaging marks and no cable loop.  My Vector ARF has this.

For the Pathfinder, replacing the leadouts is easy:  Remove first bay covering on the bottom, outside, then fish and tie new leadouts, such as a Sullivan C-D set.

Thoughts?

thanks,

Peter

[Dave Hull]

I think I showed pictures of this in a previous thread. Let me see if I can find it. If not, I can upload the sequence....

Dave

[Dave Hull]

Here was the call to action on my Vector BC/LO repair. A clubmember wanted to see how smooth my controls were--I was in the pit area by myself getting a ground test run on the engine. He reached down to work the controls back and forth and one leadout pulled right out of the wing with just fingertip pressure. The look on his face was beyond astonished.

I also had the failed crimp sleeves. They were not a suitable part:  the ID was way too large causing them to deform them a long way; the material was too hard to deform that far without cracking; they were too short to get three crimps on each; they used a sharp-edged tool to do the crimping. And crimping these hard enough to get a grip on the wire it was nearly inevitable that they would start breaking wire strands.  Other than that, it was perfect....

[Dave Hull]

This Vector was an ARF that I inherited in a trade, so I had no idea what was inside. But by looking at the kit plans, I came up with a cutout that gave enough access to pull out the bellcrank, but left the landing gear platform installed. You can see in the first picture here that I marked in the bellcrank pivot location and the two leadout holes in the bellcrank from plans dimensions. Note that the forward leadout hole is right at the aft edge of the landing gear platform. That told me how big to cut the access hole. The second picture may be a little disorienting--I left the MonoKote attached at the front and just flipped the bottom piece forward....

[Dave Hull]

With the bottom cut out, I then cut thru the wing planking, leaving enough inside the fuselage sides to make a lap-joint repair when putting the replacement planking in.

[Peter in Fairfax, VA]

Dave,

Great photos and instructions. 

Thanks!

Peter

[Dave Hull]

This is what I found inside after cutting the wing open. Note that the bolt length for the ball link is not long enough. You should have one full thread protruding from the locknut. This was solved in part on this one since LocTite was used, but still not good practice.

One technique that may help is to use an existing leadout as a "fish tape."  Attach the new leadout temporarily to the old one use exactly one layer of masking tape. You have to cut a very tiny strip, but it has worked better that other methods for me. The picture is of the new leadout taped to a piece of piano wire.

[Dave Hull]

I found that the wing planking was inconsistent in thickness, in hardness, and it had adhesive on some areas and not others. All of which made it difficult to get a clean cutout. Note the chipped edges in a couple of places. In hindsight, I could have punched a hole thru with a burr in the Dremel and probably gotten a cleaner edge. But the whole inside of the plane would have been contaminated with wood dust and ground up glue....  I probably was thinking of insetting the planking and then capping the joint with a doubler. I did not end up going that route.

I pulled the bellcrank completely out of the plane in order to wrap the new leadouts. I cleaned up the radiused holes before forming teardrop bends in the leadouts and starting the wrapping. Be sure to fish the forward leadout around the necessary structure so that you don't have to pull it all back out again. Here is where the spliced fishtape idea comes in handy to feed the leadouts from the fuselage back out thru the wingtip. On mine, since one leadout had already slid out of the plane, I inserted a piece of piano wire in from the wingtip and then grabbed it and pulled it up out of the fuse hole to "splice" it. That worked fine. I should say that I found the holes in the leadout guide big enough to pass the leadout with one wrap of tape around it.

On reinstallation, I used a longer bolt for the rod end. I also added a jam nut to the pushrod.

After checking everything eight ways from Sunday, I replanked the wing. Not pretty, but the goal was to regain all of the prior bending strength of the wing center section. It has flown with no flexing or flopping, so I'm calling the structural repair adequate.

[Dave Hull]

I suppose I have to show an "after" picture. The plastic covering that I had was not an exact color match, but it is close enough for me. And the repair seams were far less conspicuous than the original bottom piece that you put in after you glue in the wing on the ARF.

Now if I could only achieve some consistent magic inside the engine cowling....

Dave

PS--I call this the Bignose Vector because it came to me with an oversized spinner. I had the nose half rebuilt before realizing this, and since it was during an early--and bad--covid surge I was not able to get to the store to buy the correct size. When the plane flies, it looks like it is all nose dragging around the rest of the plane. Hence, Bignose!