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RV-7 #74830

AOPS

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Hello !

Just wanted to do a quick “fly-by” and introduce myself. My name is Aldo Perotto and I’ve been working on a RV-7 tail kit since February 2020 (before the Coronaverse began!). So far I have almost finished the Vertical Stabilizer (i would like a real builder to I nspect it before I close it up) and I’m currently working on “take 2“ on the Horizontal Stabilizer Front Spar ( yes, I screwed up the first one). Looking forward to any advice or pointers from the community.

https://photos.app.goo.gl/MSqZdL8Saqd7j2Vf9
https://photos.app.goo.gl/ReA8bDvwx4wDJrE6A
https://photos.app.goo.gl/c51oZu6rbRbhYwDi9
 
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Thanks for the advice John!! Didn’t know about the white pages. My plan is to finish the Horizontal Stabilizer, then we’ll bring someone over or we can take the parts over for inspection.
 
Rudder Spar to counter balance rib rivet size

I’ve been looking all over the drawings for the correct rivet size that connect R-902 (rudder spar) to R-912 (counterbalance rib). So far I’ve been unable to locate the correct rivets for this spot. I’m thinking an AN470AD4-3 will do for this but I would like to hear from the other builders on what they did. Is this another one of the RV-7 gotchas?
Thanks!
 

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The general rule is 1.3 to 1.5 times the rivet diameter to stick out. So take the material thickness of the spar, plus the material thickness of the rib, plus .187. Then multiplly that decimal by 16 to give you the closest rivet length.
For example, if the material of the spar is .032 and the rib is .025, (I'm guessing on these numbers, but you can apply this to other parts) you get .032+.025+.187= .244. Multiplly by 16, and you have just under a -4 length. I would either use a AD4704-3.5 or -4 in that case. .


I’ve been looking all over the drawings for the correct rivet size that connect R-902 (rudder spar) to R-912 (counterbalance rib). So far I’ve been unable to locate the correct rivets for this spot. I’m thinking an AN470AD4-3 will do for this but I would like to hear from the other builders on what they did. Is this another one of the RV-7 gotchas?
Thanks!
 
Just cleco one hole and maybe clamp the pieces together.
Stick in a rivet and make sure 1 1/2 times the rivet diameter is sticking out the back side.
Its that easy.
 
My guess would be AN470AD4-4's

This is from a -14 Vertical Stab, which uses the same parts.
 

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Aldo,

Almost all structural rivets are 1/8" (-4) rivets if that was part of your question.

I would suggest you buy a rivet gauge. I bought mine a long time ago. Aircraft Spruce sells them.
https://www.aircraftspruce.com/search/search.php

There are two types of gauges. One type is used to check the amount of rivet extension so you can determine the desired rivet length. As others have mentioned you are shooting for 1.5 times the diameter.

The other type of gauge is used to check the rivet after compression. I use both of these all of the time. After a while you get where you can look at the rivet and tell if it is under or over riveted but I still use the rivet gauge to check.
 
Oops

That's for the R-903 to R-902; NOT the R-912 to R-902

As stated elsewhere, the correct rivet is AN470-AD4-4 (see RV-9 updated plans, RV-14 plans, etc.)

Doh! Oops. I hate it when I do that. I have no idea what rivet I put in there. It's all closed up. Guess I will call Vans and ask just in case I used an LP4
 
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The xxx-counter balance rib to xxx-spar attachment for the RV-7, 9, 14 is an AN470AD4-4 rivet -- attached you can see the call out from the RV-7 Elevator and RV-14 Rudder...

Fear Not and Build On!
 

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Gents,

As always, thank you for your input! I’ve sent an email to the mothership for their guidance and blessing. I’m still waiting on their reply. Some of the numbers I’ve crunched came up with a -4 rivet. I’ll wait until they reply with a recommendation. However, I’ll take rapid_ascent’s recommendation and Order the rivet extension gauge. Thanks again!!
 
Aldo,

Almost all structural rivets are 1/8" (-4) rivets if that was part of your question.

I would suggest you buy a rivet gauge. I bought mine a long time ago. Aircraft Spruce sells them.
https://www.aircraftspruce.com/search/search.php

There are two types of gauges. One type is used to check the amount of rivet extension so you can determine the desired rivet length. As others have mentioned you are shooting for 1.5 times the diameter.

The other type of gauge is used to check the rivet after compression. I use both of these all of the time. After a while you get where you can look at the rivet and tell if it is under or over riveted but I still use the rivet gauge to check.

Buy one or more of these ---

https://www.cleavelandtool.com/prod...1&_sid=6d30a3779&_ss=r&variant=18378236526654
 
Rudder Trailing edge wedge gap

Hello again !

Working on the rudder trailing edge. First let me apologize if someone has asked about the RV-7 trailing edge before. Im not having that much success with the search function. Got the aluminum angle for the bonding process and while going thru the instructions, it calls for matchdrilling the angle using the skin as a guide. WTH?!?!? They had me rivet the skins to the skeleton before.
Question 1:

How can I go about that without making oblong holes or bending the skins too much?

Question 2:

Is a gap acceptable between the trailing edge wedge and the skins? I have a very small gap, and before I decide to take more material off the wedge I would like an extra pair of eyes take a look. (Pics attached)

Thanks as always and have a great weekened!!!


https://photos.app.goo.gl/kvPU7eC6o4NYFdny5

https://photos.app.goo.gl/kQ8asTXvrKCd1jHt9
 
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Just me

To me that gap is not acceptable.
I bet the dimples on both sides are hitting each other.
Shh! don't tell anyone, but I had to take a sanding block on the dimples and taper them so that the skins would mess and be supported by the wedge, not each other. You can also do a new wedge and let the holes be more towards the thicker part. On second thought, maybe a little sanding of the dimples and a new wedge would be best? I am not there in person, so I cant tell which is preferred.

What I did was position the wedge so it stuck out the back a little, tapered sanded the dimples so slightly, riveted and then filed the wedge on the trailing edge blunt with the skins
 
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No break in rudder skin trailing edge

QUOTE=Working on the rudder trailing edge.

It looks like there is no break in the rudder skin trailing edge. That is needed to get the trailing edge to lay down on the wedge. If the trailing edge rivet holes are dimpled, it is 'impossible' to break the edge.

Refer to Empennage Instructions, Page 07-07, Step 5, second paragraph.
 
To drill the holes in the trailing edge use the pre-punched holes in the skin for the position. The holes are drilled at a slight angle and not 90 degrees perpendicular to the skin. There is a angle gauge you create from the drawing.

In your pictures are the skins dimpled and the wedge countersunk?
 
Question 1 - this is what I used

I fabricated a jig/tool/? to guide my drill at the appropriate angle, and used a reamer vs. a drill bit. This is a -14 rudder, but I believe the AEX wedge is universal. I'm positive this wasn't my idea, but I'm not sure where I got the design. I *think* an 84 degree angle to the skin keeps the drill at a 90 to the chord of the wedge, which, again, is what I think you want here.

Holes on both sides of the rudder trailing edge looked good, not oblong on either side, and my rudder ended up really straight.

Hope the pictures help.

IMG_2066_25.jpg


IMG_2067_25.jpg
 
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E-701-L skin dimple MISTAKE!

Hello,

Hope all finds you well in the Coronaverse! Please see attached photos below. As I was squeezing the trigger to dimple the left elevator (E-701-L) skin, my hand slipped from the pneumatic dimple squeezer and it missed the hole and it went thru the skin. The area were it went thru is the last hole on the top of the skin near the trailing edge (outboard side), were the fiber glass cover (E-612) will be joined to the skin. Can this repaired?and if so how do I even go about it?, Or do I have to throw all of the work away? I have riveted the stiffeners to the skin and the E-615PP trim access plate to the skin. Not to mention all of the match drilling, priming and time invested. Thanks for any advice.

p.s.: a fair amount of expletives and colorful metaphors were shouted immediately after this hole was dimpled........%#%#&@T@!!!
 

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That search option here works wonders! Lots of stuff to read about extra dimples and special medals for those of us who go for that extra dimple! But I would still love to hear any extra advice. She might be the fastest RV-7 on planet after I'm done dimpling. Hehe!
 
Extra dimple

Extra dimples happen!
I think you can repair and continue and don't need to buy new parts.
The 'standard' way to fix a misaligned dimple is to clean up the hole as best you can. The hole in the underlying part will still be good, so the location can still be riveted.
Then drill, dimple and insert another rivet to the left of the damaged rivet, maintaining adequate edge distance.
FWIW I generally dimple with the hand squeezer as it gives more control. ;)
 
Extra dimples happen!
I think you can repair and continue and don't need to buy new parts.
The 'standard' way to fix a misaligned dimple is to clean up the hole as best you can. The hole in the underlying part will still be good, so the location can still be riveted.
Then drill, dimple and insert another rivet to the left of the damaged rivet, maintaining adequate edge distance.
FWIW I generally dimple with the hand squeezer as it gives more control. ;)

Thanks for the reply!! The hole that’s screwed up is a #30 hole. I have never done this before (since I’m a total newbie) and what I’m understanding is that I’m going to have to drill to the next larger sizeand fill it up; drill again next to it dimple and drive the pop rivet. I’m I going in the right direction?? Thanks again!
 
Repair

Thanks for the reply!! The hole that’s screwed up is a #30 hole. I have never done this before (since I’m a total newbie) and what I’m understanding is that I’m going to have to drill to the next larger sizeand fill it up; drill again next to it dimple and drive the pop rivet. I’m I going in the right direction?? Thanks again!

For the hole that is screwed up, I wouldn't drill it up to the next size, because the damage is too far off centre. I would carefully smooth any rough edges with a small round needle file so as to eliminate stress risers. Then re-dimple where the original dimple should have been, so that it will align with the dimple in the rib that is still good. The rivet that goes in this hole will be more cosmetic than full strength.

Then you also need a new extra rivet that will go in between the repaired rivet and the next closest rivet hole. Just draw a line through the centres of the holes parallel to the edge of the skin, then measure say 1/2 inch along this line from the repaired rivet to drill a new hole through the skin and the rib. The rib will need to be clecoed in place while you do this. Then deburr and dimple. This extra new rivet will be full strength and compensate for the damaged rivet. If you have a copy of AC 43.13-1B it gives recommendations for minimum spacings, which is typically 3 diameters.
 
Dimple Fix from mothership

Thank you for your reply! Here’s the recommended fix from Vans. It’s very similar to what you recommended.


Aldo,

Thank you for the supporting photos.

Yes, there is a relatively easy fix, and this has happened to many builders before including myself.

I would flatten this area in the skin with some flush dimple dies, then dimple (as best you can) the correct corresponding skin location. Use the standard rivet call outs in this location. As an option, you could add an additional rivet location as indicated and build on!

Later on in the build when you get ready for final paint you can at your choosing utilize a quality 2-part auto body filler and sand, feather, and blend this exterior area.

Best regards and happy building


Hope this helps anyone who encounters this problem in the future.
 
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Aldo,

I too have done a dimple gone wrong on my plane. I can't remember exactly where, maybe somewhere on the empennage as well. The pneumatic squeezer is a great tool but it can sometimes be difficult to control. As you use it more you will be get better at controlling it. I use my TATCO squeezer for most of my hand dimpling and rivet squeezing for -3 rivets. It is a great tool and for me allows the control that I need. For -4 rivets I'm not strong enough to squeeze those with the TATCO. If I didn't spend all of my time at the hangar I could probably go to the gym but that's another story. Anyway... I suggest you look into one of these tools.

On a similar theme make sure you use care on the C frame dimpler. Similar things happen there as well.
 
Got wheels on my work benches!

Put some little wheels on my work benches!!! Man, why didn’t I do this when I first started building! Ahhhh the little things.........!

Quick update on the project..........

Got the elevator almost complete and I have scheduled an EAA Tech Counselor inspection with Walt Aronow (EXP Aviation Services @ 52F) for next Friday. Hopefully, it will go well and I will have the tail complete very soon. Very happy about having an experienced 2nd pair of eyes take a look at the work we’ve done so far. QB Wings are coming in April!


https://photos.app.goo.gl/nS4tNQSML6GWPBwT8
 
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Right Elevator Rod end bearing not threading

Been searching high and low in the forums and ran into a thread of another builder with the same problem, so here it goes:

I’m at the point of installing the rod end bearings in my right elevator, and one of them threads about 1/4-1/2 turn in and then it loosens again. I’ve tried this a few times but I still don’t want to force or tap the rod. I’ve cleaned the thread and the bearing and I’m still having the same results. The nut plate looks like its centered and it has thread. So what gives????

Thanks for any help!
 
Off center

Been searching high and low in the forums and ran into a thread of another builder with the same problem, so here it goes:

I’m at the point of installing the rod end bearings in my right elevator, and one of them threads about 1/4-1/2 turn in and then it loosens again. I’ve tried this a few times but I still don’t want to force or tap the rod. I’ve cleaned the thread and the bearing and I’m still having the same results. The nut plate looks like its centered and it has thread. So what gives????

Thanks for any help!

It's off center just enough that the bearing can't thread. Carefully file the edge causing the alignment problem.
 
It's off center just enough that the bearing can't thread. Carefully file the edge causing the alignment problem.

Thanks for your reply! Man! It is ever so slightly off center. Going file it and remove a few thousands of material from the edge. Clean and boelube the thread, and try again. Thanks !
 
Rod end bearings update

@wirejock :

Thanks for the advise, sir!! Instead of using a file I went ahead and used my dremmel to remove a bit of the edge of the spar. Once that bit of material was removed, I chased the thread about a 1/4 turn to clean out any debris ( I didn’t want to mess with the locking feature). After some boelube, the rod went in! :D:D:D
 
Off center dimple hole bottom of tank skin.

Hello everyone!

It’s been a while since my last post. Life got in the way and had to take a break from the project. Now that I’m back in the saddle, progress has been real good until today that (after dimpling a lot of holes) I dimpled a tank skin off center as the skin slipped while I was driving the striking the dimple die. Since it’s a tank skin, would this be a case of “buy a new skin” or “flatten, fix for cracks, then drill 2 extra holes on either side of the bad dimple and move on”? Thanks for the help! …………I swear I need 2 Advil and a shoulder massage after all that dimpling! Hehe.



https://photos.app.goo.gl/poJxddHQTaJj8Pw58
https://photos.app.goo.gl/7AbsPh9Dn1JZFUXJ8
 
Based on the pictures it looks like the original hole has been enlarged and will have to be reworked. You could flatten, drill a #30 hole and see if that results in a usable, crack-free hole for a -4 rivet. Then drill the underlying rib flange to match, dimple skin/rib and substitute the appropriate length -4 rivet.

Can’t tell, but if that dimple sits in a countersunk part versus on a rib flange the above suggestion would not work.
 
Another alternative would be to up the rivet size to fill the hole. That’s what I would do on a rebuilt project. But then again I’m not usually working on show planes. Just depends on if that bothers you. If it’s on the bottom no one will see it.
 
Dimple

Another alternative would be to up the rivet size to fill the hole. That’s what I would do on a rebuilt project. But then again I’m not usually working on show planes. Just depends on if that bothers you. If it’s on the bottom no one will see it.

I would go with this ^ option. No one will notice a #4 rivet, and it will be strong.

Ordinarily, the fix is to flatten, redimple and add a hole equal distance either side. That works too, but this is a tank and I wouldn't want extra holes.
 
Thanks guys!! The hole is at the bottom of the skin and it wont be visible unless you go look for it. I'm leaning towards enlarging to a #4 rivet and moving on. Thanks for the help!!
 
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