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tomd

Joined: 09 Apr 2007
Posts: 7
Location: Scotia, NY

Posted: Sun Aug 12, 2007 4:41 pm Post subject: Help to fix careless mistake

I have just completed the  left wing of my MkIII classic and am ready to begin the right wing. I realized  that I have mistakenly used 1 1/4" tubing for the leading edge of the completed  left wing instead of the 1 1/2" called for in the plans. I see two choices;  drill out all of the leading edge rivets and replace the 1 1/4" with 1 1/2"  or also build the right wing with 1 1/4" tubing and keep pressing on. Obviously  the 1 1/2" is stronger but is it enough to make a difference? I appreciate any  suggestions.

   [quote][b]

Malcolmbru(at)aol.com
Guest

Posted: Sun Aug 12, 2007 4:57 pm Post subject: Help to fix careless mistake

just press on it will be weaker but  that is not where it needs to be  the strongest I new a guy that flew into a tree crash landing into a swamp and  he fixed his leading edge with a closet  rod and duck tape then flew it  bask out .  malcolm michigan



AOL.com.

  [quote][b]

John Hauck

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

Posted: Sun Aug 12, 2007 5:05 pm Post subject: Help to fix careless mistake

Obviously the 1 1/2" is stronger but is it enough to make a difference? I appreciate any suggestions.  

   	  Quote: 	
		     Tom D: The leading edge of the Kolb wing is the hardest working part of the wing.  If the wing fails, the leading edge will be the first to go. I take no short cuts on building Kolb wings.  In fact, I build them much stronger than the plans call for.  Reason:  For my own self satisfaction. If it was my wing, I would drill them out and replace with the correct size tubing. 	
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       [quote][b]

_________________
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 Aug 12, 2007 5:13 pm Post subject: Help to fix careless mistake

just press on it will be weaker but  that is not where it needs to be the strongest I new a guy that flew into a tree crash landing into a swamp and he fixed his leading edge with a closet  rod and duck tape then flew it bask out .  malcolm michigan  

  



 

   [quote] Malcolm Michigan: How much weaker? john hmkIII [b]

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

Malcolmbru(at)aol.com
Guest

Posted: Sun Aug 12, 2007 5:27 pm Post subject: Help to fix careless mistake

I saw a video of a guy named Denis, he flew a ultrastar into several high G  maneuvers trying to wreck a wing  when it did fail it was not the leading  edge that failed it was the jury strut. when he deployed his chut it subjected  the plane to moor G,s than wrecking the wing did.      malcolm  michigan 



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  [quote][b]

Richard Pike

Joined: 09 Jan 2006
Posts: 1670
Location: Blountville, Tennessee

Posted: Sun Aug 12, 2007 5:31 pm Post subject: Help to fix careless mistake

Sorry Mal, but I think that is bad  advice.

  

 Richard Pike

 MKIII N420P (420ldPoops)

 [quote]   ---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

Malcolmbru(at)aol.com
Guest

Posted: Sun Aug 12, 2007 5:34 pm Post subject: Help to fix careless mistake

If you want it dun fast and cheep just hire a poor lazy man    mal





  [quote][b]

Ralph B

Joined: 14 Apr 2007
Posts: 367
Location: Mound Minnesota

Posted: Sun Aug 12, 2007 5:35 pm Post subject: Re: Help to fix careless mistake

Replace it with the correct tubing. After it's built you will have the satisfaction of knowing it’s done right. If you don't fix it, and put the covering on, it will be harder to replace the tubing if the plane has some bad tendencies. A sharper leading edge makes for a sharper stall.



Ralph

_________________
Ralph B

Kolb Kolbra 912uls
N20386
550 hours

jindoguy(at)gmail.com
Guest

Posted: Sun Aug 12, 2007 6:34 pm Post subject: Help to fix careless mistake

Think of it like this. It's a beautiful day, the air is clear and bouyant, a perfect day to fly. The convective activity begins and before too long you're having to tug the straps a little tighter because you're getting some negative G's. Are you going to be thinking about your flying or about the weak ass leading edges in your wings? 

If you allow yourself to overlook a mistake of this magnitude, what else will you let yourself get away with? This is the proverbial slippery slope. 

If you can't bring yourself to fix this now, while it's relatively easy, stop working on it and sell it to someone who will. 

I always remember Burt Rutan's admonition in the LongEZ Plans. "Your best work is barely good enough."



Rick



do not archive



On 8/12/07,  Malcolmbru(at)aol.com (Malcolmbru(at)aol.com) <Malcolmbru(at)aol.com (Malcolmbru(at)aol.com)> wrote:[quote]      If you want it dun fast and cheep just hire a poor lazy man    mal



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  [quote][b]  http://www.matronics.com/Navigator?Kolb-List http://forums.matronics.com 

when you live at the airport.  [quote][b]

NeilsenRM(at)comcast.net
Guest

Posted: Sun Aug 12, 2007 7:19 pm Post subject: Help to fix careless mistake

Malcolm

  

 I have been a member of this list for better than 10 years and this is the  most stupid and irresponsible advice I have ever heard!!!

  

 Tom

  

 Fix the mistake. If not you or some one you love it might bite some one  else and YOU would be responsible how would you feel? Please fix it.

  

 Rick Neilsen

 Redrive VW powered MKIIIC

 [quote]   ---

GeoR38

Joined: 25 Jan 2006
Posts: 60
Location: The Villages, fl

Posted: Sun Aug 12, 2007 7:51 pm Post subject: Help to fix careless mistake

In a message dated 8/12/2007 11:20:47 P.M. Eastern Daylight Time,  NeilsenRM(at)comcast.net writes:

 [quote]   Malcolm

    

   I have been a member of this list for better than 10 years and this is    the most stupid and irresponsible advice I have ever heard!!!

    

   Tom

    

   Fix the mistake. If not you or some one you love it might bite some one    else and YOU would be responsible how would you feel? Please fix it.

    

   Rick Neilsen

   Redrive VW powered MKIIIC

   [quote]     ---

_________________
George Randolph
Firestar driver, The Villages, fl

jb92563

Joined: 23 Mar 2007
Posts: 314
Location: Southern California

Posted: Sun Aug 12, 2007 8:33 pm Post subject: Re: Help to fix careless mistake

If you want to design your own wing fine, be a test pilot and let us know how long the weaker tube lasts over years of flexing and G-Loading.



If you want to enjoy flying your aircraft as designed and benefit from all the others who have gone before you and will let us all know if something needs fixing and when,  then build it as designed.



You know the old saying about aircraft design..."Changing 1 thing changes everything"



I'd say that the price of 2 new tubes and some work is the ONLY option unless you know aircraft design and can run your tubes and new wing design  through a strength and dynamic loading analysis to verify its new lower G-loading limits. Also don't foget a physical proof loading as well to verify the results.



I'd say that redesigning the wing is a LOT more work than fixing what you stated yourself is a MISTAKE!!!



Ultimately its YOUR butt in the seat....choose wisely as aviation is unforgiving of mistakes.

_________________
Ray

Kolb UltraStar (Cuyuna UL-202)
Moni MotorGlider
Schreder HP-11 Glider
Grob 109 Motorglider

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d-m-hague(at)comcast.net
Guest

Posted: Mon Aug 13, 2007 9:19 am Post subject: Help to fix careless mistake

At 09:45 PM 8/12/2007, Tom Deiulio wrote:

  	  Quote: 	
		  ...I have mistakenly used 1 1/4" tubing for the leading edge of the completed left wing instead of the 1 1/2" called for in the plans. I see two choices; drill out all of the leading edge rivets and replace the 1 1/4" with 1 1/2" or also build the right wing with 1 1/4" tubing and keep pressing on. Obviously the 1 1/2" is stronger but is it enough to make a difference? 	


 Assuming the same wall thickness (and not knowing how it ties into the rest of the structure), the 1 1/4" tubing is only 57% as strong for bending loads as the 1 1/2".  Do you really want to fly an airplane whose wings are only half as strong as they should be?



 Fix it right.



 -Dana



 do not archive



 

 

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 "The budget should be balanced, the Treasury should be refilled, public

 debt should be reduced, the arrogance of officialdom tempered and

 controlled, and the assistance to foreign lands should be curtailed lest

 Rome become bankrupt" -Cicero, 68 B.C.    [quote][b]

tomd

Joined: 09 Apr 2007
Posts: 7
Location: Scotia, NY

Posted: Wed Aug 22, 2007 12:44 pm Post subject: Re: Help to fix careless mistake

I have decided to replace 1 1/4" tube with 1 1/2". I will be using oversized rivets (5/32) for holes that are not salvageable but I have has good luck drilling out so far. I coated my rivet heads with primer which has had a unanticipated secondary benefit, holding the rivet heads from spinning as I drill them out. Thanks to all for your help with this temporary set back.

WhiskeyVictor36(at)aol.co
Guest

Posted: Wed Aug 22, 2007 5:59 pm Post subject: Help to fix careless mistake

In a message dated 8/22/2007 4:45:25 P.M. Eastern Daylight Time,  tpd47(at)earthlink.net writes:

  	  Quote: 	
		  I coated    my rivet heads with primer which has had a unanticipated secondary benefit,    holding the rivet heads from spinning as I drill them  out. 	


 

 tom d,

  

 Thanks for posting that advice.  I have helped my buddy rebuild his  wings/ailerons a couple of times now, and spinning rivets, while drilling them  out, has always been a problem.  Hopefully I'll remember this for the next  time.   

 Bill  Varnes

Original Kolb FireStar

Audubon NJ

Do Not  Archive





Get a sneak peek of the all-new AOL.com.

  [quote][b]

olendorf

Joined: 06 Jul 2006
Posts: 140
Location: Schenectady, NY USA

Posted: Thu Aug 23, 2007 5:56 am Post subject: Re: Help to fix careless mistake

Hey Tom D,



I just noticed you are in Scotia.  I'm right near you.  I would love to come over and see your Kolb.  We have a pretty good EAA chapter also and you may want to come to the meeting Monday.  Send me an email if you want to get together.



olendorf at gmail.com

_________________
Scott Olendorf
Original Firestar, Rotax 447, Powerfin prop
Schenectady, NY
http://sites.google.com/site/kolbfirestar/

jb92563

Joined: 23 Mar 2007
Posts: 314
Location: Southern California

Posted: Thu Aug 23, 2007 6:42 am Post subject: Re: Help to fix careless mistake

I read that coating a surface the rivet is in contact with before riveting is NOT an approved method for aircraft construction.



You can however paint over the rivet. 



I forgot what the exact reason was, but it had something to due with the compression of the coating and the rivet becomming loose eventually and loosing the integrity of the joint.



Just an FYI so others dont think its a proven approved method....just the opposite actually.

_________________
Ray

Kolb UltraStar (Cuyuna UL-202)
Moni MotorGlider
Schreder HP-11 Glider
Grob 109 Motorglider

Do Not Archive

jindoguy(at)gmail.com
Guest

Posted: Thu Aug 23, 2007 7:00 am Post subject: Help to fix careless mistake

Ray, I'm not sure why riveting with a dab of zinc chromate or other primer under the rivet head would be any different than riveting together two parts that have been painted prior to riveting. Seems like it would squeeze out the liquid and maybe not do as good a job at corrosion protection, but how it would effect the clench strength of the riveted joint isn't clear. 

I'll see if I can find any reference in AC 43-13 later.



Rick



On 8/23/07, jb92563 <jb92563(at)yahoo.com  (jb92563(at)yahoo.com)> wrote: 	  Quote: 	
		  --> Kolb-List message posted by: "jb92563" < jb92563(at)yahoo.com (jb92563(at)yahoo.com)>



I read that coating a surface the rivet is in contact with before riveting is NOT an approved method for aircraft construction.



You can however paint over the rivet.



I forgot what the exact reason was, but it had something to due with the compression of the coating and the rivet becomming loose eventually and loosing the integrity of the joint. 



Just an FYI so others dont think its a proven approved method....just the opposite actually.



--------

Ray

Riverside County, CA



Do Not Archive





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-- 

Rick Girard

"Ya'll drop on in"

takes on a whole new meaning

when you live at the airport.  [quote][b]

Richard Pike

Joined: 09 Jan 2006
Posts: 1670
Location: Blountville, Tennessee

Posted: Thu Aug 23, 2007 7:07 am Post subject: Help to fix careless mistake

On my MKIII, I applied the zinc chromate and then put the rivit in while the 

paint was still wet. Solves the Problem.



Richard Pike

MKIII N420P (420ldPoops)

---

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

jb92563

Joined: 23 Mar 2007
Posts: 314
Location: Southern California

Posted: Thu Aug 23, 2007 10:54 am Post subject: Re: Help to fix careless mistake

I believe the AC 43- is where I saw it from the EAA website.



Riveting it "wet'" with zinc chromate probably eliminates the "compression" issue.



I doubt anyone will have to worry if they riveted painted surfaces, as the loose rivets will eventually reveal themselves and  merely cause some extra work.



I would think on Kolbs, that by the time that happens then aluminum fatigue would be just as much an issue and warrant rebuilds by the time the rivets show signs of being loose.



But I'm not an airframe engineer so I just go by the AC 43 guidlines.



I dont have time to discover all the problems on my own that the AC 43 has info on....I prefer to learn from others mistakes when it comes to airframe integrity

_________________
Ray

Kolb UltraStar (Cuyuna UL-202)
Moni MotorGlider
Schreder HP-11 Glider
Grob 109 Motorglider

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