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Wing structure upgrades

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k3x

Joined: 21 May 2013
Posts: 9

Posted: Wed Mar 21, 2018 4:33 pm Post subject: Wing structure upgrades

Hello to all...... I am nearly at the covering stage for the wings on a Mk3 xtra which were "quick build".   What upgrades to the structure have proven successful?

Thanks for the info.

Mike Cranson

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Thu Mar 22, 2018 4:50 am Post subject: Re: Wing structure upgrades

The only things the wings need is a reinforcement of the tip ribs, scroll down to page 21 in this link: http://oh2fly.net/oldpoops/Lexan%20rear%20enclosure.html

The only thing the fuselage needs is a brace on either side of the lower rudder post to protect against excess side loads from the tailwheel, here: http://forums.matronics.com/viewtopic.php?t=95198&highlight=tail+braces

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

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

Rex Rodebush

Joined: 10 Jan 2006
Posts: 209
Location: Branson West area, Missouri

Posted: Thu Mar 22, 2018 7:22 am Post subject: Re: Wing structure upgrades

In addition to the outboard rib angles I added a lift handle with extra supports at the wing tip.  I also added extra "trusses" on the tailwheel support.  See attached pics.

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Rex Rodebush

Joined: 10 Jan 2006
Posts: 209
Location: Branson West area, Missouri

Posted: Thu Mar 22, 2018 7:24 am Post subject: Re: Wing structure upgrades

This is the tailwheel supports.

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k3x

Joined: 21 May 2013
Posts: 9

Posted: Thu Mar 22, 2018 6:09 pm Post subject: Re: Wing structure upgrades

Thanks for the great suggestions!  Will  include the outboard  rib bracing  and tail struts for sure..... has anyone incorporated additional diagonal bracing or a .016 to .020 aluminum leading edge?..... don't want to add weight and complexity unless there is a reasonable upside.  

Best regards to all who took the time to share ideas & photos,

Mike Cranson

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Fri Mar 23, 2018 5:16 am Post subject: Re: Wing structure upgrades

Notice the diagonal braces from the leading edge to the main spar (B inside the triangle): It is not a bad idea to add a backup to them, because if the ribs between the spar and leading edge go out of column, really bad things will happen. I used some 1/2" x 1/2" x1/16" angle from Lowes.

Sheeting the leading edge has been tried, it does not help, just adds weight.

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

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

John Hauck

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

Posted: Fri Mar 23, 2018 6:03 am Post subject: Wing structure upgrades

Richard P has that right.  The standard 5/16 leading edge braces have a

tendency to fail due to vibration and time.  They are also vulnerable to

failure if your Kolb has a wing strike.  Most folks don't realize how much

stress the wing experiences from the main spar forward, including me, but

that area of the wing is working pretty hard.



Homer Kolb told me the sheet metal leading edge actually decreases the Kolb

wing's performance.  The fabric valleys between ribs enhance performance.  I

don't know, but I'll take Homer's word for it.



john h

mkIII

Titus, Alabama



 



Notice the diagonal braces from the leading edge to the main spar (B inside

the triangle): It is not a bad idea to add a backup to them, because if the

ribs between the spar and leading edge go out of column, really bad things

will happen. I used some 1/2" x 1/2" x1/16" angle from Lowes.

Sheeting the leading edge has been tried, it does not help, just adds

weight.



--------

Richard Pike

Kolb MKIII N420P (420ldPoops)

Kingsport, TN 3TN0

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

k3x

Joined: 21 May 2013
Posts: 9

Posted: Sat Mar 24, 2018 8:45 am Post subject: Re: Wing structure upgrades

Richard and John...... Great input regarding the diagonals..... surface contact between 2 round tubes is minimal to begin with.... then asking a 1/8" pulled rivet to exist happily with about 3/8" grip length and reversing loads...... ahhhhh... must be a better form.  Will fab up something that improves on existing and add one  "V brace" style with concentric contact points to either end.

Thanks! 

Mike Cranson

John Hauck

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

Posted: Sat Mar 24, 2018 11:28 am Post subject: Wing structure upgrades

I reinforced my bow tips with the standard brace in line with the main spar

plus an additional brace at 45 deg forward from the original brace.  I used

1/2" .032 6061 tubing plus I installed a sheet aluminum web  between the top

and bottom tube brace.  The web keep the tubes in column.  I can now push my

wing up by the bow tip until I lift the main gear nearest me.  Bow tips

built the standard way have a lot of flex and would probably fail it you

tried that with them.



I also used 1/2" tube braces on the leading edge of the wing.  Compressed

the tips and used about 4 or 5 rivets to secure on each end.  After 3400+

hours they are still hanging on.  



john h

mkIII SN: M3-011

Titus, Alabama



--

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

k3x

Joined: 21 May 2013
Posts: 9

Posted: Wed Mar 28, 2018 5:16 am Post subject: Re: Wing structure upgrades

Again, thanks to all for the ideas and photos..... generous and well appreciated assistance.  Here's the result..... so far.  Will try to post a photo or two as the wings progress toward covering.  

Mike Cranson

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ceengland7(at)gmail.com
Guest

Posted: Wed Mar 28, 2018 5:50 am Post subject: Wing structure upgrades

On 3/28/2018 8:16 AM, k3x wrote:

     

      	  Quote: 	
		          	  Quote: 	
		  --> Kolb-List message posted by: "k3x" <consort2(at)msn.com> (consort2(at)msn.com)



Again, thanks to all for the ideas and photos..... generous and well appreciated assistance. Here's the result..... so far.  Will try to post a photo or two as the wings progress toward covering.

Mike Cranson

	
     	
     

     Looks nice, but did you weigh that blue tubing? (How often will you     be re-wiring your wing?)

     

     Charlie

     	          		Virus-free. www.avast.com 		 	 [url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2] [/url]

williamtsullivan(at)att.n
Guest

Posted: Wed Mar 28, 2018 7:47 am Post subject: Wing structure upgrades

Mike- Looks very nice.  Where are you?  Keep posting!



                                                    Bill Sullivan

                                                    Tarboro, NC

do not archive                                                    (Formerly Windsor Locks, Ct.)

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

On Wed, 3/28/18, k3x <consort2(at)msn.com> wrote:



 Subject: Re: Wing structure upgrades

 To: kolb-list(at)matronics.com

 Date: Wednesday, March 28, 2018, 9:16 AM

 

 

 <consort2(at)msn.com>

 

 Again, thanks to all for the ideas and

 photos..... generous and well appreciated assistance. Here's

 the result..... so far.  Will try to post a photo or

 two as the wings progress toward covering.

 Mike Cranson

John Hauck

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

Posted: Wed Mar 28, 2018 8:18 am Post subject: Wing structure upgrades

Mike C, 

I've attached the Kolb Co modification of the wing rib.  You may want to

reconsider your current mod.



john h

mkIII

Titus, AL

--

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

victorbravo(at)sbcglobal.
Guest

Posted: Wed Mar 28, 2018 9:07 am Post subject: Wing structure upgrades

How is it possible to have an aircraft workshop that clean ???



Wing construction looks great to me.



Bill Berle

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

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



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

On Wed, 3/28/18, k3x <consort2(at)msn.com> wrote:



 Subject: Re: Wing structure upgrades

 To: kolb-list(at)matronics.com

 Date: Wednesday, March 28, 2018, 6:16 AM

 

 

 <consort2(at)msn.com>

 

 Again, thanks to all for the ideas and

 photos..... generous and well appreciated assistance. Here's

 the result..... so far.  Will try to post a photo or

 two as the wings progress toward covering.

 Mike Cranson

 

 

 

 

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k3x

Joined: 21 May 2013
Posts: 9

Posted: Thu Mar 29, 2018 4:55 pm Post subject: Re: Wing structure upgrades

Hello to all.....

     Good eye for detail John.... I needed to draw the line somewhere and this is where I chose to compromise a bit..... perhaps in the next, and hopefully last "pre-cover" post it will make sense. 

     All up, the wing mods added a total of 14 pounds of materials.  9.8 pounds of which I'll add tomorrow, so are not in today's photos.  Please do not assume that I believe the Kolb Mk3-X design is lacking.....  this is just stuff I had the time and inclination to fab up & see how it works out in my application.

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k3x

Joined: 21 May 2013
Posts: 9

Posted: Fri Mar 30, 2018 5:02 pm Post subject: Re: Wing structure upgrades

Late start so only finished one wing..... am somewhat tentative in posting todays photos as the signature "hungry horse" leading edges may be a touchy topic to purists.  Formed leading edges probably make no difference..... except in weight (4.7 lbs each) .... so please consider these a cosmetic indulgence.  Comparing the  rigidity in column between the two made me glad I indulged.

Mike C

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Frankd

Joined: 28 Mar 2008
Posts: 64

Posted: Fri Mar 30, 2018 8:10 pm Post subject: Re: Wing structure upgrades

Hello Mike C, 

I have a MkIII Xtra and am watching your progress.  The mods look nice and certainly will add alot of strength.  Good on ya, mate. 



BUT... I fly with a Jabiru engine of 85Hp and when I take a passenger its a little underpowered and every single pound does matter,, 



I have actually limited my passenger weight to 200Lbs for safety,  you lose some elevator authority on landing with such a forward CG and I sometime wish I could have saved a few LBs here and there.  



Now,  obviously, how your Kolb performs will depend on the engine you choose and how your CG ends up. I wish you well in your final choice. 



One other thing was I built exactly to the plans and I have never found any issue with the design where I wished it was better.. its very strong in the wing bow area and has never given me an issue. 



One tip I would give you is to put 200 lbs of sandbags in the passenger seat the first time you think of taking a passenger.. Its an eye-opening experience but will give you the feel of what to expect. 



best wishes and fun flying.  

FrankD

N1014S, MkIIIXtra.

rickofudall

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

Posted: Sat Mar 31, 2018 2:18 pm Post subject: Wing structure upgrades

Mike, The great thing about experimental aviation is that it's perfectly okay for you to make this mod. I don't know if it will get you any benefit but it will be your airplane and should stand out from other Mk 3's. Can't wait to hear how she flies.



Rick Girard

PS Those are awesome build tables. I'm going to copy them once I get the hangar cleared out to rebuild and restore the Firestar and Mk 3

On Fri, Mar 30, 2018 at 8:03 PM, k3x <consort2(at)msn.com (consort2(at)msn.com)> wrote:

 	  Quote: 	
		  --> Kolb-List message posted by: "k3x" <consort2(at)msn.com (consort2(at)msn.com)>

 

 Late start so only finished one wing..... am somewhat tentative in posting todays photos as the signature "hungry horse" leading edges may be a touchy topic to purists.  Formed leading edges probably make no difference..... except in weight (4.7 lbs each) .... so please consider these a cosmetic indulgence.  Comparing the  rigidity in column between the two made me glad I indulged.

 Mike C

 

 

 

 

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John Hauck

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

Posted: Sat Mar 31, 2018 4:35 pm Post subject: Wing structure upgrades

The wing also gets very rigid when the fabric is cemented on, shrunk, and

doped.  I have no idea how much strength the fabric adds, but it does attach

all the parts and compresses them together.  How much pressure?  I don't

know, but enough to start bending tubes if one gets overzealous.  Most of my

leading and trailing edges are bent.  I like tight fabric.



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: Sat Mar 31, 2018 4:48 pm Post subject: Wing structure upgrades

Maybe you need to make your approach and touchdown fast enough to keep the

air flowing over the empennage.  I have never had a problem running out of

elevator authority except once, but that wasn't during a landing.



Took a reporter/Army buddy flying in my MKIII at Sun and Fun many years ago.

I was showing how the MKIII handled recovery from unusual attitudes, spins,

and other stuff.  I was trying to get into an accelerated stall by diving

and making a hard pull out,  didn't work.  Then I tried making hard, steep,

turns just above the stall.  That would get it started into a stall if I

really worked at it.  Then we tried a dive with full flaps  .  This was a

first for me.  Got up over 80 mph going straight down, pulled the stick back

and the MKIII kept on going straight down.  The flaps had kicked the air off

the tail, engine was at idle.  No air, no work.  Released the flaps and she

pulled right out of it.



A higher speed approach and landing with full flaps could do the same thing,

kick the air down off the tail.



john h

mkIII

Titus, Alabama





--

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

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