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FireFly Wing Brace Repair

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jbhart(at)onlyinternet.ne
Guest

Posted: Sun Feb 12, 2012 12:00 pm Post subject: FireFly Wing Brace Repair

FireFlyers,



This is a little late but it may still be of some use especially to those 

who are in the building process.  Back on November 9, 2010 I was cleaning 

the wings when I discovered a rattle in the outboard portion of the wings.  

I was in the process of mounting the MZ 34 and so I didn't put the knife to 

the wing fabric until March 17, 2011.



What I found was that the long diagonal brace from the outboard rear corner 

to the main spar had failed in each wing.  I do not believe these to be 

really critical because the load that the outer wing panel carries is quite 

small.  But because it is there, I repaired it.  Finished the repairs on 

July 13, 2011.



I took quite a few photos, and I put them up with some description of how I 

fixed the problem.  It can be seen at:



http://jackbhart.com/firefly/firefly164.html



For those of you who have a FireFly under construction, it may be helpful to 

add a small aluminum angle to this brace to prevent the tube from going out 

of column when you shrink the wing fabric.  



Jack B. Hart FF004

Winchester, IN

John Hauck

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

Posted: Sun Feb 12, 2012 12:12 pm Post subject: FireFly Wing Brace Repair

What I found was that the long diagonal brace from the outboard rear corner

to the main spar had failed in each wing.  I do not believe these to be

really critical because the load that the outer wing panel carries is quite

small.  But because it is there, I repaired it.  Finished the repairs on

July 13, 2011.



Jack B. Hart FF004

 



Jack H/Kolbers:



Believe that is a fabric brace that does its job in tension.  As the fabric

is shrunk it prevents the outboard aft corner of the rear wing spar in line

and not pushed backwards.



Dennis Souder can correct me if I am wrong.  For that matter, anyone else

can too.  



john  h

mkIII

Titus, Alabama - Fourth day of whining about my virus that is running

rampart through the SE.

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

rickofudall

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

Posted: Sun Feb 12, 2012 12:48 pm Post subject: FireFly Wing Brace Repair

Jack, I found similar damage on my Firestar when I removed the covering. Apparently it is an area of concern for the 5 rib Firestar, too.



Rick Girard



On Sun, Feb 12, 2012 at 2:08 PM, Jack B. Hart <jbhart(at)onlyinternet.net (jbhart(at)onlyinternet.net)> wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: "Jack B. Hart" <jbhart(at)onlyinternet.net (jbhart(at)onlyinternet.net)>

  

 FireFlyers,

 

 This is a little late but it may still be of some use especially to those

 who are in the building process.  Back on November 9, 2010 I was cleaning

 the wings when I discovered a rattle in the outboard portion of the wings.

 I was in the process of mounting the MZ 34 and so I didn't put the knife to

 the wing fabric until March 17, 2011.

 

 What I found was that the long diagonal brace from the outboard rear corner

 to the main spar had failed in each wing.  I do not believe these to be

 really critical because the load that the outer wing panel carries is quite

 small.  But because it is there, I repaired it.  Finished the repairs on

 July 13, 2011.

 

 I took quite a few photos, and I put them up with some description of how I

 fixed the problem.  It can be seen at:

 

 http://jackbhart.com/firefly/firefly164.html

 

 For those of you who have a FireFly under construction, it may be helpful to

 add a small aluminum angle to this brace to prevent the tube from going out

 of column when you shrink the wing fabric.

 

 Jack B. Hart FF004

 Winchester, IN

 

 

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-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx



 

  [quote][b]

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

phactor9

Joined: 16 Jun 2011
Posts: 78

Posted: Sun Feb 12, 2012 1:12 pm Post subject: FireFly Wing Brace Repair

Hi Jack:

 

I just examined mine. I'm about a month away from covering (cold here in TN!). Those are the longest lengths of 5/16th to begin with, at over a yard each.

 

Sure enough, both of mine have a curve. The points of attachment at the trailing edge corner and the brace 9" away are both very nearly level. But they both then attach to the 5" spar 2+ inches up from level inducing a small curve. Thanks for bringing this up.

 

Phil H

FF-11-4-076



 

FF-11-4-076

--- On Sun, 2/12/12, Jack B. Hart <jbhart(at)onlyinternet.net> wrote:



  	  Quote: 	
		  

From: Jack B. Hart <jbhart(at)onlyinternet.net>

Subject: FireFly Wing Brace Repair

To: kolb-list(at)matronics.com

Date: Sunday, February 12, 2012, 3:08 PM



 --> Kolb-List message posted by: "Jack B. Hart" <jbhart(at)onlyinternet.net (jbhart(at)onlyinternet.net)>



FireFlyers,



This is a little late but it may still be of some use especially to those 

who are in the building process.  Back on November 9, 2010 I was cleaning 

the wings when I discovered a rattle in the outboard portion of the wings.  

I was in the process of mounting the MZ 34 and so I didn't put the knife to 

the wing fabric until March 17, 2011.



What I found was that the long diagonal brace from the outboard rear corner 

to the main spar had failed in each wing.  I do not believe these to be 

really critical because the load that the outer wing panel carries is quite 

small.  But because it is there, I repaired it.  Finished the repairs on 

July 13,  2011.



I took quite a few photos, and I put them up with some description of how I 

fixed the problem.  It can be seen at:



http://jackbhart.com/firefly/firefly164.html



For those of you who have a FireFly under construction, it may be helpful to 

add a small aluminum angle to this brace to prevent the tube from going out 

of column when you shrink the wing fabric.  



Jack B. Hart FF004

Winchester,  --> httphttp://forums.matronics.com/" target=_blank>http://forums.matronics.com



	
 [quote][b]

John Hauck

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

Posted: Sun Feb 12, 2012 2:29 pm Post subject: FireFly Wing Brace Repair

Jack, I found similar damage on my Firestar when I removed the covering.

Apparently it is an area of concern for the 5 rib Firestar, too.



Rick Girard

 

More so concern for the skimpy lateral bracing of the leading edge tube that

keeps those five little rib noses in column.  Those little 5/16" OD .028"

wall 6061 aluminum tubes are all that carry the weight and stress of the

Firestar and Ultrastar.  After losing both wings back to the main spar on my

Firestar, I am really sensitive about these braces.  In fact, I increased

the lateral bracing on my MKIII wings to 1/2" OD .032 wall 6061 to insure

the rib noses will stay in column on my airplane.



Don't think the fabric brace on the bow tip will help keep the rib noses in

column.  It is a fabric brace in tension only.



john h

mkIII

Titus, Alabama

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

John Hauck

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

Posted: Sun Feb 12, 2012 2:30 pm Post subject: FireFly Wing Brace Repair

Sure enough, both of mine have a curve. The points of attachment at the

trailing edge corner and the brace 9" away are both very nearly level. But

they both then attach to the 5" spar 2+ inches up from level inducing a

small curve. Thanks for bringing this up.



Phil H

 

Normal to have a curve in the 5/16 tube brace.  This tube brace works in

tension only.



john h

mkIII

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

WhiskeyVictor36(at)aol.co
Guest

Posted: Sun Feb 12, 2012 3:02 pm Post subject: FireFly Wing Brace Repair

Jack & gang,

  

 Yup, same thing happened to my original FireStar.  Left wing at 38  hours and right wing at 115 hours.  Fixed it (similar to Jack's repair but  a little different) and they are still OK at 426 hours.  Perhaps  it's caused by vibration or stress when folding the wings, which I do every  time I fly.  And I do have the optional 1/2" angles attached to the end  ribs per Kolb.

  

  Bill  Varnes

Original Kolb FireStar

Audubon NJ

Do Not  Archive



  

  In a message dated 2/12/2012 3:00:38 P.M. Eastern Standard Time,  jbhart(at)onlyinternet.net writes:

  	  Quote: 	
		  What I    found was that the long diagonal brace from the outboard rear corner 

to    the main spar had failed in each wing.     

	


 [quote][b]

jbhart(at)onlyinternet.ne
Guest

Posted: Mon Feb 13, 2012 8:29 am Post subject: FireFly Wing Brace Repair

At 02:11 PM 2/12/12 -0600, you wrote:

 	  Quote: 	
		  



Jack H/Kolbers:



Believe that is a fabric brace that does its job in tension.  As the fabric

is shrunk it prevents the outboard aft corner of the rear wing spar in line

and not pushed backwards.




	


John,



I am confused.  If shrinking the fabric tries to pull the rear spar forward 

toward the wing leading edge, anything that prevents this is in compression. 

It would seem logical that if the shrunk fabric is pulling the rear spar 

forward and inward from the wing end bow.  To prevent this from happening 

something has to push back at the corner to prevent this from happening.  

What am I missing here?



Your concept is not supported by what I found.



Jack B. Hart FF004

Winchester, IN

John Hauck

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

Posted: Mon Feb 13, 2012 8:55 am Post subject: FireFly Wing Brace Repair

I am confused.  If shrinking the fabric tries to pull the rear spar forward

toward the wing leading edge, anything that prevents this is in compression.



It would seem logical that if the shrunk fabric is pulling the rear spar

forward and inward from the wing end bow.  To prevent this from happening

something has to push back at the corner to prevent this from happening.  

What am I missing here?



Your concept is not supported by what I found.



Jack B. Hart FF004

Winchester, IN

 

Perhaps Dennis Souder can explain this much better than I can.  He or Homer

Kolb explained it to me.



I think the fabric is actually trying to squeeze the bow tip area of the

wing into an oblong shape since the sides of the bow tip area are not

equidistant.



It is the rounded curve of the bow tip that encourages the aft outboard

corner of the wing to be push backwards as fabric is shrunk.  If there was a

strong compression brace installed at a 45 degree angle from the center of

the bow tip curve back to the main spar, this would help prevent the

problem.  I have those 45 degree bow tip braces installed on my MKIII.



The problem may not be as pronounced with the small curve of the FF and SS

bow tip as it is with the US, FS, MKIII, and Kolbra, which uses a much

larger curve.



This very small 5/16" tube brace was never intended for compression. If it

was, it would have been a much larger, more substantial brace.



This little 5/6" brace may also act as a drag brace, since there is no other

bracing in the bow tip to prevent the wind stream from pushing aft on it.



Figuring out how to sequentially shrink the bow tip fabric to reduce this

tendency may help.  My primary concern when I shrink wing fabric is to get

that fabric as tight as I can without distorting the wing, not necessarily

what is happening out on the bow tip.  I build for performance.



Sorry if this explanation doesn't do the job.  This is day 5 of the dreaded

virus.  That's my excuse and I'm sticking to it.  



Maybe someone else that understands what is happening can explain the

situation better than I can.



john h

mkIII

Titus, Alabama

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

captainron1(at)cox.net
Guest

Posted: Mon Feb 13, 2012 8:00 pm Post subject: FireFly Wing Brace Repair

Jack this is an excellent post, and a good repair. Appreciate it.



Ron Mason

KFHU

M3X



=============================

---- "Jack B. Hart" <jbhart(at)onlyinternet.net> wrote: 



=============




FireFlyers,



This is a little late but it may still be of some use especially to those 

who are in the building process.  Back on November 9, 2010 I was cleaning 

the wings when I discovered a rattle in the outboard portion of the wings.  

I was in the process of mounting the MZ 34 and so I didn't put the knife to 

the wing fabric until March 17, 2011.



What I found was that the long diagonal brace from the outboard rear corner 

to the main spar had failed in each wing.  I do not believe these to be 

really critical because the load that the outer wing panel carries is quite 

small.  But because it is there, I repaired it.  Finished the repairs on 

July 13, 2011.



I took quite a few photos, and I put them up with some description of how I 

fixed the problem.  It can be seen at:



http://jackbhart.com/firefly/firefly164.html



For those of you who have a FireFly under construction, it may be helpful to 

add a small aluminum angle to this brace to prevent the tube from going out 

of column when you shrink the wing fabric.  



Jack B. Hart FF004

Winchester, IN

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