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Question about building vertical fin

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victorbravo(at)sbcglobal.
Guest

Posted: Fri Apr 29, 2016 12:57 pm Post subject: Question about building vertical fin

I have finished constructing the two triangular horizontal stabilizers, and have started on the vertical fin and steel rear fuselage ring.



As many of you know by heart, the vertical "spar" tube on the back of the fin is one inch diameter tube. The leading edge is 3/4 inch tube. When I riveted the gusset to one side of this intersection, it "pulled" the 3/4 inch tube over flush with the side of the one inch tube. So when I went to install the gusset on the other side I realized the fin leading edge is no longer on the centerline of the fin. 



I'm sure this is not a BIG deal in terms of safety, but it's not right from a quality perspective. Is there a known "fix" for this? I don't want to drill out the rivets and goober up the rivet holes, especially since I cannot 100% locate those previous holes if I want to replace the tube.



Has anyone else run into this while building the fin?

Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities

Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Fri Apr 29, 2016 2:12 pm Post subject: Question about building vertical fin

Bill,  Are you using Clecos to hold the parts together prior to permanent riveting?  Jim Baker [url=tel:4054265377]405 426 5377[/url]--

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Apr 29, 2016 2:48 pm Post subject: Question about building vertical fin

I believe in the Ultrastar, Firestar, and MKIII (before the days of the MKIIIx) construction manuals black plastic electrical tape can be used as a shim to give the two different size tubes a snug fit.

 

I don't remember there being a "fitting" problem when building the tail section.

 

By all means build you parts with cleco's first.  They are much easier to drill out than case hardened mandrels.  Would have thought any self respecting engineer would have known that.  wink...wink   

 

If I wasn't happy with the fit, I'd drill the rivets and start over.  Might as well get practice removing SS rivets now.  You'll need that expertise later on for sure.  I'll bet you can figure out how to set the new holes to match the ones in the blind tube.

 

john h

mkIII

Titus, Alabama

 

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Jim Baker

Sent: Friday, April 29, 2016 5:12 PM

To: kolb-list(at)matronics.com

Subject: Re: Question about building vertical fin



 

Bill,



Are you using Clecos to hold the parts together prior to permanent riveting?



Jim Baker

[url=tel:4054265377]405 426 5377[/url]



--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

victorbravo(at)sbcglobal.
Guest

Posted: Fri Apr 29, 2016 6:29 pm Post subject: Question about building vertical fin

Putting black electrical tape on would not be the best solution, because we're talking 1/8 inch on both sides of the smaller tube to make it "even" with the larger tube. That's way too much tape I'm guessing.



I had been using Clecos extensively, like any self-respecting sheet metal Cessna modification/repair guy  My error was to do the drill/cleco/rivet operation on one side of the top of the fin, before cleco'ing the other side of the fin. So without any resistance from the other side, the clecos and rivets on the first side just pulled the gusset over tight against the first side. I realized the error just about as the last rivet went pop ! 



I can easily shim the other side of the fin leading edge tube with a piece of wood, sanded to a taper. That will allow me to continue the structural assembly without weakening or goobering out the holes by having to drill again and enlarge the hole. A wood shim will make it so the leading edge of the fin is perfectly on the centerline of the rest of the fin. As an old washed up free flight model builder, I thankfully have a supply of balsa and spruce sticks 



What I learned from watching this forum (and speaking to a Zenair builder) was the technique of driving out the mandrel first before drilling off the SS rivet.That has allowed me to remove a few rivets without damaging the hole in the tube or wrecking the sheet metal gusset. I was pleasantly surprised by the fact that it was not a big bloody battle to drive out the mandrel.



I do have several "hole finder" tools that can match the rivet holes,a nd they work reasonably well, but not perfectly. With blind rivets you lose the big advantage that solid AN rivets give you, which is the rivet truly filling an oblong hole. Thehole for a pop rivet must be better quality.



I also notice that the instruction booklet does not specify the rivets, it only says "stainless steel rivets are 3 times stronger than aluminum". A bag of rivets came witht his kit,a nd I have made the assumption that they were supplied by Kolb. Does anyone know this is right or wrong?



Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



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

On Fri, 4/29/16, John Hauck <jhauck(at)elmore.rr.com> wrote:



 Subject: RE: Question about building vertical fin

 To: kolb-list(at)matronics.com

 Date: Friday, April 29, 2016, 3:48 PM

 

 I believe in the Ultrastar,

 Firestar, and MKIII (before the days of the MKIIIx)

 construction manuals black plastic electrical tape can be

 used as a shim to give the two different size tubes a snug

 fit.  I don't remember there

 being a "fitting" problem when building the tail

 section.  By all means build you parts

 with cleco's first.  They are much easier to drill out

 than case hardened mandrels.  Would have thought any self

 respecting engineer would have known that.  wink...wink  

   If I wasn't happy with the

 fit, I'd drill the rivets and start over.  Might as

 well get practice removing SS rivets now.  You'll need

 that expertise later on for sure.  I'll bet you can

 figure out how to set the new holes to match the ones in the

 blind tube.  john hmkIIITitus, Alabama  From: owner-kolb-list-server(at)matronics.com

 [mailto:owner-kolb-list-server(at)matronics.com] On Behalf

 Of Jim Baker

 Sent: Friday, April 29, 2016 5:12 PM

 To: kolb-list(at)matronics.com

 Subject: Re: Question about building

 vertical fin  Bill,

 

 Are you using Clecos to hold the parts together prior to

 permanent riveting?

 

 Jim Baker

 405 426

 5377

 

 --

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Fri Apr 29, 2016 6:40 pm Post subject: Question about building vertical fin

Are you working on the rear tube of the upper vertical stabilizer to the top of the tail post?



If you are, 1/4" slop between tail post and trailing edge is way too much.  I think that is what you said, 1/8" space on each side.



john h

mkIII

Titus, Alabama



--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

byoungplumbing(at)gmail.c
Guest

Posted: Fri Apr 29, 2016 7:57 pm Post subject: Question about building vertical fin

any chance you could put the tube in a vise and oval it slightly so the transition is less abrupt without weakening anything...

 Boyd On Apr 29, 2016 2:59 PM, "Bill Berle" <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)> wrote: 	  Quote: 	
		  --> Kolb-List message posted by: Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>

 

 I have finished constructing the two triangular horizontal stabilizers, and have started on the vertical fin and steel rear fuselage ring.

 

 As many of you know by heart, the vertical "spar" tube on the back of the fin is one inch diameter tube. The leading edge is 3/4 inch tube. When I riveted the gusset to one side of this intersection, it "pulled" the 3/4 inch tube over flush with the side of the one inch tube. So when I went to install the gusset on the other side I realized the fin leading edge is no longer on the centerline of the fin.

 

 I'm sure this is not a BIG deal in terms of safety, but it's not right from a quality perspective. Is there a known "fix" for this? I don't want to drill out the rivets and goober up the rivet holes, especially since I cannot 100% locate those previous holes if I want to replace the tube.

 

 Has anyone else run into this while building the fin?

 

 

 Bill Berle

 www.ezflaphandle.com  - safety & performance upgrade for light aircraft

 www.grantstar.net           - winning proposals for non-profit and for-profit entities

 

 

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rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sat Apr 30, 2016 8:11 am Post subject: Question about building vertical fin

Don't deform the tube or use a wood shim (water and shrinkage will gradually loosen the joint), joggle the gusset plate. Tony Bingelis shows a really neat way to do this in his books that you can get from the EAA.The best place to buy rivets is McMaster Carr. They have the best price and availability and you'll get genuine Pop Rivets. Steel rivets, if I remember correctly, come in three types. Steel with steel mandrel, Stainless Steel with steel mandrel and Stainless Steel with Stainless Steel mandrel. The first is best for very light gauge tubing, the last is the strongest.

Rick Girard

On Fri, Apr 29, 2016 at 10:57 PM, B Young <byoungplumbing(at)gmail.com (byoungplumbing(at)gmail.com)> wrote:

 	  Quote: 	
		  

any chance you could put the tube in a vise and oval it slightly so the transition is less abrupt without weakening anything...

 Boyd On Apr 29, 2016 2:59 PM, "Bill Berle" <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)> wrote: 	  Quote: 	
		  --> Kolb-List message posted by: Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>

 

 I have finished constructing the two triangular horizontal stabilizers, and have started on the vertical fin and steel rear fuselage ring.

 

 As many of you know by heart, the vertical "spar" tube on the back of the fin is one inch diameter tube. The leading edge is 3/4 inch tube. When I riveted the gusset to one side of this intersection, it "pulled" the 3/4 inch tube over flush with the side of the one inch tube. So when I went to install the gusset on the other side I realized the fin leading edge is no longer on the centerline of the fin.

 

 I'm sure this is not a BIG deal in terms of safety, but it's not right from a quality perspective. Is there a known "fix" for this? I don't want to drill out the rivets and goober up the rivet holes, especially since I cannot 100% locate those previous holes if I want to replace the tube.

 

 Has anyone else run into this while building the fin?

 

 

 Bill Berle

 www.ezflaphandle.com  - safety & performance upgrade for light aircraft

 www.grantstar.net           - winning proposals for non-profit and for-profit entities

 

 

 ===========

 -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Kolb-List

 ===========

  FORUMS -

 eferrer" target="_blank">http://forums.matronics.com

 ===========

 WIKI -

 errer" target="_blank">http://wiki.matronics.com

 ===========

 b Site -

           -Matt Dralle, List Admin.

 rel="noreferrer" target="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 	


 	




-- 

“Blessed are the cracked, for they shall let in the light.”   Groucho Marx

_________________
The smallest miracle right in front of you is enough to make you happy....

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sat Apr 30, 2016 8:31 am Post subject: Question about building vertical fin

 As many of you know by heart, the vertical "spar" tube on the back of the fin is one inch diameter tube. The leading edge is 3/4 inch tube. When I riveted the gusset to one side of this intersection, it "pulled" the 3/4 inch tube over flush with the side of the one inch tube. So when I went to install the gusset on the other side I realized the fin leading edge is no longer on the centerline of the fin.

 



Bill Berle

 

 

 

 

 

Hi Bill B/Kolbers:

I finally woke up and read the above when I was looking at a comment by Rick G.

If I am not mistaken, you can twist the leading edge tube away from the vertical tube enough to get it centered on the larger tube and attach the other gusset.  IIRC it is the way I was able to get a nice tight connection between the two dissimilar size tubes.

john h

mkIII

Titus, Alabama

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

neilsenrm(at)gmail.com
Guest

Posted: Sat Apr 30, 2016 9:45 am Post subject: Question about building vertical fin

Bill

Like John suggests try to pull the tube over to get better alignment. If this doesn't work drill out the rivets and file a small indentation or fish mouth in the smaller tube to get clearance for better alignment. It shouldn't take much. Take your time and do it right. These Kolbs are over engineered but your life could depend on getting it right. 

The manual doesn't call for it but all the mating of tubes on my airplane were done as if they were going to be welded with a (I think it is called a fish mouth joint). Takes a bit of extra work but the joints are strong and you can't pull the tubes out of alignment when you rivet the gussets on.  Used a semi round and rat tail file to fit the tubes. It will never show but I know they were done the best I could do. I also pulled all my rivets by hand. I think I was able to get the rivets seated better but on occasion I would get a rivet that would pop too easy. Not sure one would know if it was done with a air rivet puller. I drilled out a bunch of rivets. Used a sharp bit and drilled on a bit of an angle if the rivets started to spin I would increase the angle.

Over the years people always seem to want to say "aren't you nervous about flying a plane you built". I can truly say I might feel nervous if someone else built it.

Worth what you paid for it.

Rick Neilsen

Redrive VW Powered MKIIIC

On Sat, Apr 30, 2016 at 12:31 PM, John Hauck <jhauck(at)elmore.rr.com (jhauck(at)elmore.rr.com)> wrote:

 	  Quote: 	
		  

 

 As many of you know by heart, the vertical "spar" tube on the back of the fin is one inch diameter tube. The leading edge is 3/4 inch tube. When I riveted the gusset to one side of this intersection, it "pulled" the 3/4 inch tube over flush with the side of the one inch tube. So when I went to install the gusset on the other side I realized the fin leading edge is no longer on the centerline of the fin.

 



Bill Berle

 

 

 

 

 

Hi Bill B/Kolbers:

I finally woke up and read the above when I was looking at a comment by Rick G.

If I am not mistaken, you can twist the leading edge tube away from the vertical tube enough to get it centered on the larger tube and attach the other gusset.  IIRC it is the way I was able to get a nice tight connection between the two dissimilar size tubes.

john h

mkIII

Titus, Alabama

victorbravo(at)sbcglobal.
Guest

Posted: Sun May 01, 2016 7:04 am Post subject: Question about building vertical fin

Thank you all for the advice and putting your brain cells on this issue for me. 



John H the alignment problem I was referring to was not a gap between the tubes, it was the tubes not being on the same centerline... when viewed from above the aircraft, the 3/4" diameter leading edge tube was "flush" with the starboard side of the 1" diameter rear vertical fin "post" or fin spar tube. Because the two tubes were different sizes, having the smaller tube even with of the stbd. side of the larger tube meant that there was a "step" on the port side.



After I flew yesterday (C172) I spent the afternoon and evening fixing this problem. I finally just drilled out the rivets and made new gussets. I did "fish-mouth" the tube a little bit with a file so it stayed centered, but the real solution was to have both sides cleco'ed and verified on center before riveting. My error was that I did one side completely before starting the other side, and thislaziness caused the problem.



Another thing I have been doing is "working" and forming the gussets to be in better contact with the tubes. I have curled the edges of the gussets so they begin to wrap around the tube just past the rivet line, and i have done a little hammering and metal brake work. This is necessary when you have two tubes that are different sizes. 



I clearly understand that the different tube sizes were chosen to minimize weight wherever possible, but tthis adds significant time to making the gussets and keeping the tubes aligned during assembly. On an aircraft that is never going to be operated as a Part 103 UL (like the Firestar 2), it would seem that using the same diameter tubes for the perimeter of the fin/stabilizer would make it quite a bit easier. The weight difference would be small, compared to the time savings of a few hours, and the improvement in ease of construction.



All that being said, my fin is straight now  Not that I'm trying to build a champion show plane (definitely not), but I want to make everything as straight as I can to reduce the number and size of "permanent" trim tabs.

Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



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

On Sat, 4/30/16, Rick Neilsen <neilsenrm(at)gmail.com> wrote:



 Subject: Re: Question about building vertical fin

 To: "kolb-list(at)matronics.com" <kolb-list(at)matronics.com>

 Date: Saturday, April 30, 2016, 10:45 AM

 

 Bill

 Like John suggests try to pull the

 tube over to get better alignment. If this doesn't work

 drill out the rivets and file a small indentation or fish

 mouth in the smaller tube to get clearance for better

 alignment. It shouldn't take much. Take your time and do

 it right. These Kolbs are over engineered but your life

 could depend on getting it right. 

 The manual doesn't call for it

 but all the mating of tubes on my airplane were done as if

 they were going to be welded with a (I think it is called a

 fish mouth joint). Takes a bit of extra work but the joints

 are strong and you can't pull the tubes out of alignment

 when you rivet the gussets on.  Used a semi round and rat

 tail file to fit the tubes. It will never show but I know

 they were done the best I could do. I also pulled all my

 rivets by hand. I think I was able to get the rivets seated

 better but on occasion I would get a rivet that would pop

 too easy. Not sure one would know if it was done with a air

 rivet puller. I drilled out a bunch of rivets. Used a sharp

 bit and drilled on a bit of an angle if the rivets started

 to spin I would increase the angle.

 Over the years people always seem

 to want to say "aren't you nervous about flying a

 plane you built". I can truly say I might feel nervous

 if someone else built it.

 Worth what you paid for

 it.

 Rick NeilsenRedrive VW Powered

 MKIIIC

 On Sat, Apr 30, 2016 at

 12:31 PM, John Hauck <jhauck(at)elmore.rr.com>

 wrote:

  

 As many of you know by heart, the vertical

 "spar" tube on the back of the fin is one inch

 diameter tube. The leading edge is 3/4 inch tube. When I

 riveted the gusset to one side of this intersection, it

 "pulled" the 3/4 inch tube over flush with the

 side of the one inch tube. So when I went to install the

 gusset on the other side I realized the fin leading edge is

 no longer on the centerline of the fin.

  

 

 Bill Berle

 

     Hi Bill

 B/Kolbers:I finally woke up and read the

 above when I was looking at a comment by Rick

 G.If I am not mistaken, you can

 twist the leading edge tube away from the vertical tube

 enough to get it centered on the larger tube and attach the

 other gusset.  IIRC it is the way I was able to get a nice

 tight connection between the two dissimilar size

 tubes.john hmkIIITitus,

 Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Sun May 01, 2016 10:51 am Post subject: Question about building vertical fin

I use a piece of aluminum tubing to roll the edges of the gussets down.  Does a good job and is quick.



john h

mkIII

Titus, Alabama





--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

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