Help/advice needed on flap center bearing block

jcarne · #1 09-15-2018, 01:19 PM

Gents, I am trying to install the flap system. This system is similar between a few models and the main question applies to more than the -7A so I figured the general section would be a good spot.

I went to drill the center flap bearing block and you can see in the following picture that it is centered quite well on the rear spar.

20180915_123013 by Jereme Carne, on Flickr

However, the story underneath is not so pretty. The baggage rib got pretty mangled as the edge distance wasn't there.

Capture by Jereme Carne, on Flickr

So the questions is, what would you guys do with this? I have an email into Van's on this but I'm wondering if I can cut the rib off and just use a bolt like a lot of people seem to do here. The bolt would then be going through the block, baggage floor, seat floor and rear spar. Also, replacing the rib won't help as the hole will still be close enough to the edge to do this again. Any thoughts on what you might do?

Ralph Inkster · #2 09-15-2018, 04:06 PM

Hole position in the rear spar carry through is perfect & catching the end of the baggage rib doesn't help or hinder anything. The plastic bearing is only there to prevent the torque tube from flexing and is not subjected to a lot of force.
Keep on going!

Jpm757 · #3 09-15-2018, 07:59 PM

How about a .040 doubler?

Paul 5r4 · #4 09-16-2018, 07:42 AM

Agree with Ralph.

jcarne · #5 09-16-2018, 09:28 PM

Thanks for the replies guys, I'm inclined to agree but I'll keep you posted on what Van's says.

jcarne · #6 09-22-2018, 08:24 AM

Gents, just to update this thread in case anyone else runs into this problem. Van's said go ahead and trim the flange of the rib. This required me to remove a few rivets on the baggage floor so I could peel the corner up. I also decided to put in an access door in the floor to gain access to the area. For part of the flange I found that a spiral scroll saw blade was the trick, just like flossing teeth. Finally I flossed it with some 400 grit turning cloth to deburr.

On a separate note, this fix was very difficult due to the limited access. Just be mega super duper careful when drilling this hole and go super slow.

If one of the moderators wants to put solved in the thread title go right ahead.

Arie · #7 09-22-2018, 10:58 AM

As a matter of intrest, as I am about to drill that hole. How would you do it again without running into this problem. My centre flap bearing block is made exactly to plans. And the way I see it, its position is " predetermined" by the flap torque tube.

jcarne · #8 09-22-2018, 03:30 PM

Quote:

Originally Posted by Arie

As a matter of intrest, as I am about to drill that hole. How would you do it again without running into this problem. My centre flap bearing block is made exactly to plans. And the way I see it, its position is " predetermined" by the flap torque tube.

Yes I'm not entirely sure that anyone really gets good edge distance. I think what happened was when I was drilling the drill bit grabbed the side of the nylon bearing block like it does from time to time, this pulled the bit through rather than letting it go through gently. I would just be careful during drilling and accept what ever edge distance you get. I would be curious how others came out but I have never seen a picture of this area.