Elevator Problems

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bmurrish
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Elevator Problems

Post by bmurrish »

The pictures don't show how bad the problem is so hopefully I can describe the problem in detail. I am attempting to put the right elevator skin on my –8 and have a problem. Everything fits fine until I try to cleco the E-703/E-704/E-713 sub-assembly on. I have not match drilled any holes at this point. The predrilled skin holes do not line up with the rib holes and by making them do so, the outer trailing edge bends downward. I thought the E-704 might have been misdrilled, so I tried the E-703/E-704/E-713 subassembly from the left elevator and it does the same thing. I also took the suspect E-703/E-704/E713 subassembly and tried it on the left elevator and the trailing edge looks great. I have pretty much eliminated the ribs as the problem. I then thought the skin holes might have been misdrilled. I took skin hole measurements in every direction and matched them with the measurements from the left elevator and they are the same, so I have eliminated that as the problem. I then figured the trailing edge was not straight so I unclecoed everything and checked the bend in my bending brake and it looks perfect. The bending brake is straight as well and worked fine when bending all other edges. I clecoed E-702 spar to the skin only and rechecked and the bend still looks fine. The E-709 rib on the inboard edge even lines up perfect so that leads me to believe the skin is bent correct. I can not figure out what is causing the downward bend in the outboard trailing edge. Have you seen this happen before? Any suggestions?
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Bill Murrish
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captain_john
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Post by captain_john »

It is difficult to say, but I am going to guess that the skin wasn't straight when inserted into the brake.

Image

See here how we have the "vee" of the brake aligned with the "vee" of the skin?

I bet you had the skin horizontal on the table and closed the bend to favor one side.

:? CJ
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bmurrish
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Post by bmurrish »

I really thought it was bent wrong, but the thing that gets me is why does the E-702 spar and E-709 rib on the other end of the elevator line up perfectly with the skin? Also the -8 skin comes pre bent, so you are just completing the bend. I used the same exact bending procedure with the rudder and left elevator (which was done after this happened and it is good). I have an email in to Vans and I am going to let Loyd Remus who runs a builder's assistance program here take a look at it.
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Post by Spike »

I would say the first thing to do is walk away from it for at least 24 hours. Go home tonight, have a beer, and watch a movie with the family. Come back to it tomorrow. :)

Knock the simple things out first. Are you sure this is not a "left" vs "right" thing and that the skeleton is not flipped 180 degrees?

-- John
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captain_john
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Post by captain_john »

Also, it looks like you could afford to bend it some more. Maybe cleco-ing it together, inserting the dowel and bending it some more... but in the other direction this time?

8) CJ
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Elevator Problems

Post by Spike »

Interesting idea.
 
Are there any other pictures of your elevator parts that are more inclusive? It might make it easier to see what is going on if we can see more of the big picture.
 
-- John
 

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bmurrish
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Post by bmurrish »

I got a reply from Vans. They think it was originally bent incorrectly during manufacturing. They are sending me a new skin. :-)

As far as the ribs being upsidedown or backwards. I am 100% they are on the right way.
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Elevator Problems

Post by Spike »

Excellent Bill!!! Glad to hear it. Vans is definitely a stand up company.
 
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bmurrish
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Post by bmurrish »

I am very happy with Van's customer service. I still plan on letting Loyd Remus who runs a builder's assistance program here check it out to see if it can be salvaged. I sure hate to have to drill all the stiffener rivets out to put them on the new skin. Hopefully I can get this all sorted out before my wings arrive.
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Post by Ron »

Bill, I would ask Van's for new stiffener material,even if you have to pay, the time saved and the finished product will be well worth it. Ron :)
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bmurrish
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Post by bmurrish »

I just got back from visiting Loyd Remus. He looked at the elevator and said the original factory bend looks like it may have been off by 1/8" causing the pre-drilled skin holes to be off a half hole length when lining up the skin and ribs. He said I have two options. The first is to get the new skin from Van's (which they are already replacing for free) and start all over. This means either drilling out the 108 rivets holding the stiffeners on or getting new stiffeners and going through the entire cutting and deburring process (which he recommended if I go with the new skin). Or the second option is to drill the misaligned holes with a #30 bit (using the skin holes as the guide) and using opps rivets. If I cleco on the the entire skin except the bottom holes of E-703/E-704 end rib, the edge does not bend downward and looks normal. The only holes that would need to be enlarged and opps riveted would be the 9 rivets on the bottom side of the elevator attaching E-703/E-704. What would you pick in this situation? :?
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bmurrish
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Post by bmurrish »

Almost forgot, all the stiffeners would cost me $22.10 plus shipping.
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Post by Spike »

Interesting. That is exactly what happened to my training kit. The bend was slightly off so by the time I aligned the parts up and riveted the part was warped. I dont think that Van's makes that kit though so I didnt think to mention it. Personally, I dont know what I would do. Though I think eventually I would eat the stiffeners and remake them. It really doesnt take that much time to do. One, maybe two evenings and you can remake them all assembly line style.

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Post by tshort »

So, Bill - what did you end up doing? They may have a batch of these done the same - my R elevator has done the exact same thing and looks exactly like that ... I'd post a pic but I can't log into the gallery.

Guess I'll be calling Van's tomorrow. I'm pretty sure I'll redo the skin and stiffeners. I was down in the basement working today after a 2 week hiatus (travel, etc) and was not very happy to see this. Four letter words were flying everywhere and then I remembered this post... now I feel better. I'm still done for the evening, though...

Thomas

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Post by tshort »

Just got off the phone with Van's; 2 minute conversation, they're replacing the skin and all stiffeners free of charge. Should ship today (!).

Gotta reiterate what a great company they are to deal with - I'm very happy with the customer service.

Thomas

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Post by Guest »

very interesting...ImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImageImage

Guest

Post by Guest »

Funny. I JUST bent my right elevator skin last night. Same exact thing happened to me. I ordered my kit in March. Sounds like they had some sort of booboo going on around that time period.

Spike
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Post by Spike »

Wow, that is interesting. I wonder if they had the brake setup incorrectly or something.
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NoSlack
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Re: Elevator Problems

Post by NoSlack »

Solution
1. Straighten the ribs and set the flanges to 90°
2. Cleco and drill 703 to 713 then remove 703 and cleco in 704 to 713
3. Dimple the parts and then cleco them back together.
4. They'll fit - if not the ribs and flanges weren't straightened correctly.

The ribs have tooling die holes. The ribs and rivet holes are punched prior to hydroform using the tool die holes. Then, again using the tooling die holes the ribs are hydroformed If the tooling dies are not damaged, the part was hydroformed correctly.

Oblong rivet holes will crack pretty quick. That 2,000 lbs of force to squeeze the #3 rivet has to go somewhere so an out of round hole ends up exerting differing forces on your hole that end up cracking the material.

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RobDob
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Re: Elevator Problems

Post by RobDob »

Wow......16 years for the solution! :P :mrgreen: :)
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