VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-14 (https://vansairforce.net/community/forumdisplay.php?f=109)
-   -   Another Hard To Reach Rivet (Rudder) (https://vansairforce.net/community/showthread.php?t=145512)

Reflex 01-07-2017 03:27 PM

Another Hard To Reach Rivet (Rudder)
 
I must have done something wrong or missed an instruction. Last night I dry fitted (haven't riveted the skins together yet) my rudder skins. I wanted to see how everything fit before I put adhesive on the trailing edge.

What I found was an extremely tight fit between the skins on the last rivet on the bottom edge of the rudder. It's so close that the rivet actually touches the shop head of the rivet from the other skin. In addition, when in its current position, the factory head sits just a bit proud in the dimple.

Thoughts?

Please see below:







Thanks for your input.

Fred

Tom023 01-07-2017 04:04 PM

I had same issue. Rather than risk fouling it up I took the safe way out and used an Mk-319-BS rivet and moved on. I've seen photos of others who also took this route.

rvbuilder2002 01-07-2017 04:19 PM

The latest rev. level of the rudder plans (dated 12/03/15) specify final drilling #33 and installing MK-319BS rivets in the aft most holes.

Available HERE

You don't have to use blind rivets on all the holes specified if you have a way to install solid rivets.

BTW, it looks like you may be over squeezing some of your rivets slightly (they look a little on the thin side)

Reflex 01-07-2017 04:37 PM

Gentlemen,

Thanks for the input. I'll use the MK-319BS rivets.

Regarding the rivet height, I agree, they look thin. However they fit perfectly in the gauge. I've found that some of the call-outs can be just a tad short (and some a bit long). In this case, 3-3.5's were specified. Going through the skin, R00904B-1, and R-00918 seemed like a bit of a stretch. They looked short so I checked them with calipers....they were of proper length so I used them.

Should I drill out and use 3-4's? Hate to drill out that .016 skin.

Thanks,

Fred

cczarnik 01-07-2017 05:12 PM

Minimum driven head thickness .038 per Mil Spec. That's a lot thinner than what you get with the 1.5D rule of thumb for the shop head. For reference that is very thin- less than a #60 drill bit. Source: https://www.vansaircraft.com/public/Specs.htm. So you're probably ok.

For tight rivets look up the indirect back rivet technique video on EAA's website. That might not even work for this spot though- I used pull rivets.

wjb 01-07-2017 07:46 PM

I hated these guys ... Van's should have offset them so you wouldn't have the space constraint.

I used the EAA indirect back rivet technique. Worked OK in the end, but my sailor gene surfaced in the process (%$#*!)

rvbuilder2002 01-07-2017 07:52 PM

Quote:

Originally Posted by Reflex (Post 1140067)
Gentlemen,

Thanks for the input. I'll use the MK-319BS rivets.

Regarding the rivet height, I agree, they look thin. However they fit perfectly in the gauge. I've found that some of the call-outs can be just a tad short (and some a bit long). In this case, 3-3.5's were specified. Going through the skin, R00904B-1, and R-00918 seemed like a bit of a stretch. They looked short so I checked them with calipers....they were of proper length so I used them.

Should I drill out and use 3-4's? Hate to drill out that .016 skin.

Thanks,

Fred

As described in Section 5, the rivets called out in the plans will result in shop heads that meet the Mil Spec (posted by cczarnik), but not necessarily meet the rule of thumb which is what the rivet gauges are measuring to.
The reason this is done is because often when a rivet size is selected that will meet the rule of thumb it is actually just a bit on the long side which makes it
much more likely that a novice builder will have a bunch of them clinch over and then they start removing rivets and things go bad quickly.

A good practice with the rivet gauges is is to get it close to meeting the diam. requirement. You are then probably also close to meeting the height requirement. This usually results in meeting both dimensions for the Mil Spec.

Some builders make there own rivet gauges with holes and notches based on the Mil spec values instead of the 1.5/.5 rule of thumb values.

And no, I don't think you need to remove any rivets.... I was just mentioning it as something you might want to keep in mind as you continue.

rvbuilder2002 01-07-2017 07:57 PM

Quote:

Originally Posted by cczarnik (Post 1140072)
Minimum driven head thickness .038 per Mil Spec. That's a lot thinner than what you get with the 1.5D rule of thumb for the shop head.

Actually, using the .5 rule of thumb for thickness the nominal would be about .047 thick so only about .009 difference. A couple in the photo looked like they might be thinner than the Mil Spec minimum, but maybe not.

Av8rRob 01-07-2017 08:16 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1140064)
The latest rev. level of the rudder plans (dated 12/03/15) specify final drilling #33 and installing MK-319BS rivets in the aft most holes.

Available HERE

You don't have to use blind rivets on all the holes specified if you have a way to install solid rivets.

BTW, it looks like you may be over squeezing some of your rivets slightly (they look a little on the thin side)


Scott, the link you attach only show a revision 1 dated 5/1/14 on it. Do you have a new link?

rvbuilder2002 01-08-2017 12:18 PM

Quote:

Originally Posted by Av8rRob (Post 1140122)
Scott, the link you attach only show a revision 1 dated 5/1/14 on it. Do you have a new link?

That is the most recent one. Accessible from THIS PAGE .

It looks like the only change at that time was correcting some file formatting so that the .PDF was fully searchable so the rev dates wont necessarily match.

Av8rRob 01-08-2017 02:23 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1140239)
That is the most recent one. Accessible from THIS PAGE .

It looks like the only change at that time was correcting some file formatting so that the .PDF was fully searchable so the rev dates wont necessarily match.


Ok, I just don't see the change you mentioned of the blind rivets.

rvbuilder2002 01-08-2017 03:01 PM

Page 07-12 in that doc is the most updated rev level. It shows blind rivets.
Ignore the date. The date on the page has nothing to do with the date the doc was posted.

Av8rRob 01-08-2017 06:48 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1140276)
Page 07-12 in that doc is the most updated rev level. It shows blind rivets.
Ignore the date. The date on the page has nothing to do with the date the doc was posted.

Hmm, I only see blind rivets on the top aft part of the rudder and no change to the bottom aft section we're talking about.

Fyi it also refers to section 5.7 ( which is folded trailing edge) should be 5.8

cczarnik 01-08-2017 07:39 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1140113)
A good practice with the rivet gauges is is to get it close to meeting the diam. requirement. You are then probably also close to meeting the height requirement. This usually results in meeting both dimensions for the Mil Spec.

Hey Scott- thx for this. Question (and part of the motive for my original response)- with some of the length callouts I'm getting rivets that have a shop head too tall per mil-spec at 1.5D width. To get to spec the diameter is sometimes more than 1.5. What is best practice? Do I leave a shop head @ 1.5D and too thick? Or do I squeeze past 1.5D to flatten the head to mil spec? I think I saw this most on the rudder (thin skins) and used a reamer so holes were pretty tight. Apologies to OP if off topic but I thought stick it here since we were talking about shop head dimensions too- thx.

Mudfly 01-08-2017 08:51 PM

Quote:

Originally Posted by Av8rRob (Post 1140337)
Hmm, I only see blind rivets on the top aft part of the rudder and no change to the bottom aft section we're talking about.

Fyi it also refers to section 5.7 ( which is folded trailing edge) should be 5.8

I just finished building a second rudder:), so I'm familiar with this situation. The main issue I discovered that prevents you from being able to get a regular rivet in the hole in question is the following statement in step 2 on pg. 7-10 "Rivet the aft eight holes common to the bottom rib, rudder skin assembly and the attach strip. See Figure 1 and Page 07-12 Figure 2".
The problem is that the most aft rivet in the bottom rib is not included on "aft eight holes" as shown in the digram on the plans. In step 3, the plans state "Use the blind rivets called out in Figure 1 to attach R-00904A-1 Bottom Rib to the R-00904B-1 Bottom Rib." Then in step 5, plans state "Rivet the remaining holes in lower edges of R-00901-L-1 and R-00901-R-1 Skins common to R-918 Attach Strips and R-00910 Horn Brace using the rivets called out in Page 07-12 Figure 2. Problem is: once the blind rivets are in place on the R-00904A-1 and R-00904B-1 Bottom ribs, you are unable to accomplish the following statement in step 2 .. "The trailing edge will have to be peeled slightly apart to access the aft two rivets."
Long story short. If you rivet that last rivet "before" the two bottom rib pieces, R-00904A-1/R-00904B-1, are blind riveted together, you are able to easily "peel", as stated in step 2, the trailing edge apart enough to access this aft rivet. I used a no hole yoke, but I think a regular should work too. I also don't like when the plans say to "peel" the trailing edges apart. It leads to possible confusion that the trailing edges are actually bonded at this point with either tape or pro seal. I think "separate the aft portion of bottom rib" would be a better phrase to use here.

HAL Pilot 01-09-2017 02:53 PM

Aloha

I fabricated a wedge bucking bar from bar stock that slides in there. so far works pretty well. had to pry the skin/flanges apart a bit for the aft rivet.

one side is scooped out with ribs on the outside and the other is beveled slightly.

https://www.dropbox.com/s/9v5lzvpy9o...B1%5D.jpg?dl=0

https://www.dropbox.com/s/xo07rgwa2g...B1%5D.jpg?dl=0

Polar 01-09-2017 06:31 PM

Quote:

Originally Posted by Mudfly (Post 1140368)
I just finished building a second rudder:), so I'm familiar with this situation.

I've been checking out your blog from time to time. It's been helpful, thanks.
How come you built another rudder??

Sorry for the thread hijack...

Mudfly 01-09-2017 07:57 PM

Rudder Rebuild
 
I apologize for thread drift as well and the long post. However, final paragraph is related to thread.

Polar,
I ordered the parts for the rudder rebuild just after I finished the first one. There were a few things I wasn't happy with. Looking back, I should have thought about it for a few days before ordering the new parts. Now as a more "experienced" builder I would probably just build on. However, since I had the parts I went ahead with the new one. I think the main reason I wanted to redo was because of a twist in the rudder. When placed on a flat surface, once side of the rudder was completely flat and the other was raised about .5" and would "rock" back and forth. The twist could have been due to several reasons, but I believe it was caused when I incorrectly (prematurely) pulled the final side the adhesive tape off and the the trailing edge stuck together in the incorrect position (one hole off on the trailing edge). I pulled back loose and re-stuck, but think I may have pulled a twist in the process. For the second rudder, I followed the plans exactly regarding using the tape (section 5), and did not pull the final backing from the tape until all other riveting was complete. I think for the first one, I was concerned that if I waited until all other riveting was complete I would not be able to the get to the tape and peel it back. It turned to to be a non issue on the second one and the tape worked perfectly. I had every hole in the trailing edge clecoed and bonded with the tape on only one side. I then started slowly removing the protective backing from the final side slowly and removing/replacing clecos as I went. Worked great and the "new rudder" has only a very slight twist and overall build quality is much better (as it should be with a few more rivets under my belt:). I did have a slight setback during the new rudder though. I had just finished priming all the parts and had them inside the shop drying. I had the skins propped up against my work tables. I was cleaning up at the end of the day and happy that things were going pretty smoothly. However, I have a retractable electrical cord hanging from the ceiling and as I went to retract it, the plug end slipped out of my hand as it was retracting and the plug end of the cord slammed into the right side skin and put a solid golf ball size ding right in the middle of the skin. Had to reorder a new skin. Lesson learned..you can never let your guard down with most parts of this project or it WILL bite you:).

PS. I still need to update my blog and show the changes I made on the second rudder build. One thing (and related to this thread) that I did was to not rivet that lower rib together until I had those aft 9 (not 8 as stated in the plans) rivets set. I was able to lift the skins easily and squeeze those rivets. The first rudder, as seen on my blog, I actually used solid rivets on that lower rib and was not able to "separate" this ribs to get to those aft rivets. Think I set with a very thin piece of metal. Followed plans and did not do that on the second rudder.

Reflex 01-10-2017 06:09 AM

Quote:

...you can never let your guard down with most parts of this project or it WILL bite you
That's sound advice! After thinking my way through most the rudder, I was closing up the right side, had a very nice thickness of Pro Seal on the AEX, had made jigs to hold the rudder straight due to the double taper, a good helper was bending the skin back, and the pop rivets were going in quickly. This was going to be a short evening and things were coming out well.

Upon riveting the last two stiffeners, I noticed that I had not gotten two of the stiffeners "under" the shear clips. I tried to drill out the pop rivets and managed to destroy one of the shear clips. It would have taken a total of about 5 seconds to double check the placement of the stiffeners relative to the shear clips. I just let my guard down.

Parts will be here Friday or Monday. Lesson learned.

Fred


All times are GMT -6. The time now is 07:27 AM.