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Rudder Trailing Edge Countersinking
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PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 7:00 am Post subject: Rudder Trailing Edge Countersinking

Well, I do hate to have to ask another question on the heels of my last

one (un-fluting), but here goes.



Countersinking the rudder (9A) TE last night (R-916), it became apparent

after a couple holes that the holes are enlarged by the CS.  There is no

way to CS to the correct depth without enlarging the holes.  I've been

trained that countersinking should *never* cause the hole to enlarge -

if it does, the material is too thin - but this seems to be a special

case (piece sandwiched between two skins for double-flush riveting).

The instructions don't speak to the issue.  Am I doing this correctly?



Paul



9A QB #1176



HS, VS done

peter(at)mather.com
Guest

Posted: Tue Mar 21, 2006 7:41 am Post subject: Rudder Trailing Edge Countersinking

Paul



It sounds like you may have the wedge slightly too far forward into the rudder so that you have drilled very slightly too close to the thin edge. I didn't see any significant enlargement when I did it although it is very marginal. Given the double headed rivets it probably doesn't matter if the hole is slightly enlarged although it is obviously important that the dimples in both skins sit cleanly into the wedge. Do use the tank sealant to glue the edge before rivetting and let it set properly with every hole clecoed onto a straight edge.



Best regards



Peter

[quote] ---

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 8:04 am Post subject: Rudder Trailing Edge Countersinking

Too far forward?  No, the edge was prepunched #40 and then was

match-drilled.  The holes are just where they're supposed to be.



Well, then, I'm entirely confused about this because, as I said, there

is NO WAY to countersink to the proper depth without enlarging the holes

some - and it's not a trivial amount, either.  They are quite noticeably

larger - although the countersinks are done just right - the skin

dimples do fit perfectly.  



Thanks for the response.

--

gerf(at)gerf.com
Guest

Posted: Tue Mar 21, 2006 8:28 am Post subject: Rudder Trailing Edge Countersinking

The wedge was pre-punched ?  I'm assuming only the skins were 

pre punched and you match drilled into the wedge.  I think what 

Paul is saying is that you need to re-position the wedge 

further AFT relative to the skins, that way you will be 

countersinking into the thicker section of the wedge.  Which 

may necessitate you replacing the wedge.



I had a a similar issue although perhaps not as pronounced.  I 

bonded my trailing edges with T-88 epoxy which made them a lot 

stronger.  Maybe post a picture ?



g



[quote] 

 

 <PFolbrecht(at)starkinvestments.com>

 

 Too far forward?  No, the edge was prepunched #40 and then was

 match-drilled.  The holes are just where they're supposed to be.

 

 Well, then, I'm entirely confused about this because, as I said, there

 is NO WAY to countersink to the proper depth without enlarging the holes

 some - and it's not a trivial amount, either.  They are quite noticeably

 larger - although the countersinks are done just right - the skin

 dimples do fit perfectly.  

 

 Thanks for the response.

 

 

 --

dan(at)rvproject.com
Guest

Posted: Tue Mar 21, 2006 8:43 am Post subject: Rudder Trailing Edge Countersinking

 	  Quote: 	
		   Too far forward?  No, the edge was prepunched #40 and then was

 match-drilled.  The holes are just where they're supposed to be.


	


Was the AEX wedge drilled from the factory, or did you match drill it using 

the holes in the skin?  If the wedge itself came drilled from the factory, 

then you're right...not much choice in the matter.  If the wedge had no 

holes in it when you started, then it's possible you located it too far 

forward when you drilled it...which shifts the holes toward the thin end of 

the wedge...but it's NOT a huge deal.



Take a look at the flap brace on the RV-7/8 and you'll see that it gets 

countersunk between the dimpled wing skin and the untouched flap hinge. 

Those c-sink'd holes end up huge.  It's OK because that layer is sandwiched 

between other layers.



Take a look at the left elevator rear spar, trim tab spar, etc.  Same deal. 

Stuff gets c-sunk and enlarged, and it's OK because it's sandwiched between 

at least two other layers that don't have enlarged holes.



I may be mistaken, but I believe Van's mentions this scenario in the 

construction manual.  In any case, your rivet's manufactured & shop heads 

are both bearing against un-enlarged material.  My 2 cents is, rivet that 

sucker and press on.  If you have any doubts, call Van's Builder's 

Assistance (503-678-6545, no wonder how I can just spout that from 

*memory*!) and they'll probably tell you the same thing.



At least that's my 2 cents...hope it puts you at ease.



)_( Dan

RV-7 N714D

http://www.rvproject.com

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 8:56 am Post subject: Rudder Trailing Edge Countersinking

Yes, the wedge was indeed pre-punched.



I've only done 3 holes so, even if I've screwed-up this far (and now I

don't think that I have), it's not likely a loss.  I have been told

enlargement of the holes is indeed inevitable here.

--

rv7(at)b4.ca
Guest

Posted: Tue Mar 21, 2006 9:07 am Post subject: Rudder Trailing Edge Countersinking

On 8:55:33 2006-03-21 "Folbrecht, Paul" <PFolbrecht(at)starkinvestments.com>

wrote:

 	  Quote: 	
		   I've only done 3 holes so, even if I've screwed-up this far (and now I

 don't think that I have), it's not likely a loss.  I have been told

 enlargement of the holes is indeed inevitable here.


	


Another option is to flush rivet one side and leave the other side

square-headed.  It's less pretty, but it's going to be a lot stronger.  If

you're countersinking both sides of that wedge and finding that the

countersinks are meeting each other, you'll have a knife-edge around the

hole, which isn't condusive to long rivet life.



On the Elevator, at least, you could put the square heads on the underside.



-Rob

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 9:15 am Post subject: Rudder Trailing Edge Countersinking

Thanks, Dan.  These were mostly my thoughts as well (both rivet heads

are secure and the TE is just squeezed in) but I thought I should ask.

(Having finally ruined my first part recently (and a skin at that), I

think I may be "erring" hard on the side of caution lately.)



This section of the instructions doesn't speak to this issue, and, I

just reviewed section 5 as well, on countersinking, and didn't see it

addressed there either.  Perhaps it is in there somewhere.  Or maybe

this is something that's assumed to be obvious. :-}



Paul

--

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 10:28 am Post subject: Rudder Trailing Edge Countersinking

Well, what I'm running into, everybody should be running into.



I'd like to hear from other builders who have done the rudder recently

(or just remember it well).  Did you notice the TE holes significantly

enlarged by the countersinking?



Do not archive

--

dwight(at)openweave.org
Guest

Posted: Tue Mar 21, 2006 11:37 am Post subject: Rudder Trailing Edge Countersinking

Paul,



Well ... I don't want to -swear- to it, but I do believe I had a bit of

hole enlargement when I c'sunk mine. I just did it a few months ago, even

though I'm close to finishing my fuselage, because I got my original small

rudder replaced by Van's ... but at the time was busy with other things and

just stuck it on the shelf until a good time to assemble it. That "good time"

finally arrived back in November. 



At the time my thinking was (a) the holes are pre-punched so I can't make

any adjustments there and (b) it is going to be tightly sandwiched between

the two skins and (c) it'll be held firmly in place with proseal for added

measure. Thus ... I didn't give it much thought.



If in doubt, call Van's. (I need to give 'em a call on another issue myself

sometime today or tomorrow.)



  -- Dwight



do not archive 



On Tue Mar 21 13:24:39 2006, Folbrecht, Paul wrote :

 	  Quote: 	
		  Well, what I'm running into, everybody should be running into.



I'd like to hear from other builders who have done the rudder recently

(or just remember it well).  Did you notice the TE holes significantly

enlarged by the countersinking?

lsbrv7a(at)yahoo.com
Guest

Posted: Tue Mar 21, 2006 11:58 am Post subject: Rudder Trailing Edge Countersinking

My holes were enlarged, but it looked like the skins nearly meet and fill the void.  I glued mine Saturday and plan on squeezing the rivets with a hand squeezer with a set ground to a matching angle. (Someone on the list mentioned he did his that way, and it worked well.)



"Folbrecht, Paul" <PFolbrecht(at)starkinvestments.com> wrote:   

Well, what I'm running into, everybody should be running into.



I'd like to hear from other builders who have done the rudder recently

(or just remember it well). Did you notice the TE holes significantly

enlarged by the countersinking?



Do not archive





Sherman Butler

RV-7a Empennage

Idaho Falls

		

---------------------------------

Bring photos to life! New PhotoMail  makes sharing a breeze.

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 12:10 pm Post subject: Rudder Trailing Edge Countersinking

It seems I probably worried about this a bit too much.



(But, when you're new to metal working, and you read things like how

failing to debur can cause stress cracks that can bring your airplane

down hundreds of hours later, you want to make sure all the t's are

crossed and so forth... :-})



Do not archive



P.S. Yes I realize no single crack is going to cause a structural

failure unless it goes unchecked for a very long time...



--

Hopperdhh(at)aol.com
Guest

Posted: Tue Mar 21, 2006 12:12 pm Post subject: Rudder Trailing Edge Countersinking

Sherman,

 

Are you going to alternate the direction of the rivets?  That seems  like a 

good method.  In fact mine would look awful if I hadn't done that  because I 

didn't use any adhesive.  That was a mistake.  As it is, I  have a slight "sine 

wave" if you look closely at the rudder.  It isn't that  bad but it could be 

better.  If I hadn't alternated the rivets it would be  curled about 4 inches!

 

I set the rivets with a squeezer as far as possible, then finished with the  

gun -- a flush set against my back riveting plate.  It seems to me like a  

squeezer with dies ground to that angle would tend to bend the rivets.

 

Good luck,

 

Dan Hopper

RV-7A Flying since July '04 -- 145 wonderful hours

 

 

 

In a message dated 3/21/2006 2:59:40 P.M. Eastern Standard Time,  

lsbrv7a(at)yahoo.com writes:






My  holes were enlarged, but it looked like the skins nearly meet and fill 

the  void.  I glued mine Saturday and plan on squeezing the rivets with a hand  

squeezer with a set ground to a matching angle. (Someone on the list mentioned 

 he did his that way, and it worked well.)



"Folbrecht, Paul"  <PFolbrecht(at)starkinvestments.com> wrote:   --> RV-List  

message posted by: "Folbrecht, Paul" 

Well, what I'm running into,  everybody should be running into.



I'd like to hear from other builders  who have done the rudder recently

(or just remember it well). Did you  notice the TE holes significantly

enlarged by the countersinking?



Do  not archive





Sherman Butler

RV-7a Empennage

Idaho  Falls

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 12:19 pm Post subject: Rudder Trailing Edge Countersinking

Grinding the dies to match the angle is a great idea.  I'll do that.



Hopefully the elevators are a close match and the same dies can be used.

--

retasker(at)optonline.net
Guest

Posted: Tue Mar 21, 2006 1:02 pm Post subject: Rudder Trailing Edge Countersinking

This method works great.  I used my pneumatic squeezer and some rivet 

sets I made myself that were ground to the correct angle.



However, make sure that you use a straight die to start the rivets, 

otherwise the rivet may bend as noted in another post.



Basically, start all the rivets - squash them as far as you can without 

the flat rivet set hitting the skins - and then finish them with the 

angled rivet set.



Don't let the angled set rotate   .



Dick Tasker



Folbrecht, Paul wrote:



[quote]



Grinding the dies to match the angle is a great idea.  I'll do that.



Hopefully the elevators are a close match and the same dies can be used.

--

Albert Gardner

Joined: 10 Jan 2006
Posts: 455
Location: Yuma, AZ

Posted: Tue Mar 21, 2006 3:26 pm Post subject: Rudder Trailing Edge Countersinking

You might the RV-9 List archives also. This issue comes up from time to

time.  The RV-9 wedge comes prepunched and countersinking will enlarge the

holes. I match drilled the wedge holes into a piece on 1/8" al strip that I

bought at Ace Hardware. I put clecos in about ever 10th or 12th hole to keep

it in place and the strip provided a hole for the countersink pilot. Flip

the wedge and do the other side then clamp the wedge, pull the clecos and

csk the remaining holes. On the other side of those holes you can csk by

hand. You will have the same problem on the main spar for the tank attach

screw nutplates but you can just use a short piece attached with clecos thru

the #40 nutplate attach holes and the strip will provide a pilot hole.

Albert Gardner

RV-9A N872RV

RV-10 30%

Yuma, AZ

_________________
RV-9A N872RV
RV-10 N991RV

truflite(at)yahoo.com
Guest

Posted: Tue Mar 21, 2006 3:28 pm Post subject: Rudder Trailing Edge Countersinking

No way to get around enlarging the hole.  Work slowly

and it should work out okay.  As long as the skins sit

down well in the countersink, you are good to go. 

Move on.



Dave

--- "Folbrecht, Paul"

<PFolbrecht(at)starkinvestments.com> wrote:



[quote] 

 <PFolbrecht(at)starkinvestments.com>

 

 Well, what I'm running into, everybody should be

 running into.

 

 I'd like to hear from other builders who have done

 the rudder recently

 (or just remember it well).  Did you notice the TE

 holes significantly

 enlarged by the countersinking?

 

 Do not archive

 

 

 --

George McNutt

Joined: 09 Jan 2006
Posts: 30

Posted: Tue Mar 21, 2006 6:41 pm Post subject: Rudder Trailing Edge Countersinking

Hi Paul



Just a thought, -  are you using a 100 degree aviation countersink and 

not 82 degree hardware store type??



George in Langley BC

Folbrecht, Paul wrote:



 	  Quote: 	
		  



Too far forward?  No, the edge was prepunched #40 and then was

match-drilled.  The holes are just where they're supposed to be.



Well, then, I'm entirely confused about this because, as I said, there

is NO WAY to countersink to the proper depth without enlarging the holes

some - and it's not a trivial amount, either.  They are quite noticeably

larger - although the countersinks are done just right - the skin

dimples do fit perfectly.  



Thanks for the response.

Jim Carlton

Joined: 09 Jan 2006
Posts: 10

Posted: Tue Mar 21, 2006 7:20 pm Post subject: Rudder Trailing Edge Countersinking

On Tuesday 21 March 2006 03:19 pm, Folbrecht, Paul wrote:



 	  Quote: 	
		  

 



 My holes were enlarged, but it looked like the skins nearly meet and

 fill the void.  I glued mine Saturday and plan on squeezing the rivets

 with a hand squeezer with a set ground to a matching angle. (Someone on

 the list mentioned he did his that way, and it worked well.)



 "Folbrecht, Paul" <PFolbrecht(at)starkinvestments.com> wrote:   --> RV-List

 message posted by: "Folbrecht, Paul"

 Well, what I'm running into, everybody should be running into.



 I'd like to hear from other builders who have done the rudder recently

 (or just remember it well). Did you notice the TE holes significantly

 enlarged by the countersinking?




	


I wish I had a picture of the wedge, but I chucked the microcage to the 

drillpress, made a jig out of a couple of blocks of wood and fed the 

predrilled wedge thru, keeping the work perpendicular to the bit. I didn't 

notice much enlarging of the holes, but maybe I set the microstop too 

shallow? Dunno, but I clecoed everything up and the dimpled skin set in fine. 

I was so pleased with the fit I decided to try using epoxy instead of proseal

. 

After mixing up a batch of West Systems with a slow hardener and making a 

slurry with Cabosil to a thick consistency, I used a small brush and painted 

it on to the skins at the trailing edge. I layed the skin onto the bench with 

the wedge clecoed to the trailing edges and followed the steps spelled out in 

the plans. Yes, I did this by myself where the directions call for an assist 

to fold the skins over while you reach in to rivet the clips to the ribs or 

stringers. I used a "sky hook" to hold the top skin overhead while I slowly 

lowered it into place and proceeded with the blind rivets. Yep, it was a 

handful, but kinda fun and I didn't get too much epoxy all over!



After I finished up the riveting, I clecoed the whole trailing edge, very 

little oozed out needing cleanup, and weighted the rudder down to let it dry 

overnight. Next morning it was rock solid, clecoes easily popped out and I 

cleaned up the holes. 



I back riveted the whole length against a length of 1 1/4 angle iron clamped 

to the edge of the workbench. Except for my overzealous gun work, (really 

dislike those little smilies!) in a spot or two, it came out really great. I 

may spot fill the shop heads and lay a layer of glass over the edge and 

really clean it up smooth. Anybody think I should worry about smoking rivets 

working through?



Jim

PFolbrecht(at)starkinvest
Guest

Posted: Tue Mar 21, 2006 7:26 pm Post subject: Rudder Trailing Edge Countersinking

Certainly using the correct tools.



The job (c-sinking) is done now and turned out well.  I now check each hole after c-sinking; each rivet sits just a hair under flush.



Quit a bit early tonight after reading the "instructions" for mixing proseal.  Sounds like a blast.



do not archive

________________________________



From: owner-rv-list-server(at)matronics.com on behalf of G McNutt

Sent: Tue 3/21/2006 8:44 PM

To: rv-list(at)matronics.com

Subject: Re: Rudder Trailing Edge Countersinking






Hi Paul



Just a thought, -  are you using a 100 degree aviation countersink and

not 82 degree hardware store type??



George in Langley BC

Folbrecht, Paul wrote:



 	  Quote: 	
		  



Too far forward?  No, the edge was prepunched #40 and then was

match-drilled.  The holes are just where they're supposed to be.



Well, then, I'm entirely confused about this because, as I said, there

is NO WAY to countersink to the proper depth without enlarging the holes

some - and it's not a trivial amount, either.  They are quite noticeably

larger - although the countersinks are done just right - the skin

dimples do fit perfectly.



Thanks for the response.

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