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Lift Strut / Stress question

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planecrazzzy
Guest

Posted: Sat Mar 04, 2006 8:17 pm Post subject: Lift Strut / Stress question

Hey Guys,

               I've seen my"stock" Lift struts "wiggle/shake" in flight.....I'll be changing over to the streamline struts....



  I'm sure they'll still flex alittle....



 I've heard on the list that the chromemoly on the end of the lift struts have cracked on a couple of different planes....

  Here's a picture of two holes in a lift strut....I'm looking for YOUR opinion if this looks like trouble waiting to strike....or are these streamline struts

"bullet proof" where these hole won't crack with repeated flexing....



                      Gotta Fly...

                                      Mike in MN N381PM ( still improving it )

Pitot tube holes in lift strut.2.bmp

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Kirk Smith

Joined: 10 Jan 2006
Posts: 78
Location: SE Michigan

Posted: Sat Mar 04, 2006 9:56 pm Post subject: Lift Strut / Stress question

" Here's a picture of two holes in a lift strut....I'm looking for YOUR

opinion if this looks like trouble waiting to strike"



YIKES!!!!!!  Maybe it doesn't have the moly inserts at the end but has a

full length moly tube inside the streamline strut?



Do not archive

planecrazzzy
Guest

Posted: Sun Mar 05, 2006 4:43 am Post subject: Re: Lift Strut / Stress question

You've got a GOOD POINT....I wrote John and asked him if a Chromemoly tube is running the Full Lenght....If that Streamline is just a 

"Sleeve" then those holes wouldn't be a problem....



 If not, Then what "you" said...YIKES !!!



               Gotta Fly...

                                Mike in MN

Richard Pike

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

Posted: Sun Mar 05, 2006 4:43 am Post subject: Lift Strut / Stress question

Those holes would be real close to the top of my  "Bad idea" list.



Richard Pike

MKIII N420P (420ldPoops)



do not archive

planecrazzzy wrote:

 	  Quote: 	
		   



 Hey Guys,

                I've seen my"stock" Lift struts "wiggle/shake" in flight.....I'll be changing over to the streamline struts....



   I'm sure they'll still flex alittle....



  I've heard on the list that the chromemoly on the end of the lift struts have cracked on a couple of different planes....

   Here's a picture of two holes in a lift strut....I'm looking for YOUR opinion if this looks like trouble waiting to strike....or are these streamline struts

 "bullet proof" where these hole won't crack with repeated flexing....



                       Gotta Fly...

                                       Mike in MN N381PM ( still improving it )



 --------

 The more people I know....

 The more I like MY DOG

 .

 .

 .

 .

 .Do not archive





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=19614#19614





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 http://forums.matronics.com//files/pitot_tube_holes_in_lift_strut2_131.bmp

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

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

jdm(at)wideworld.net
Guest

Posted: Sun Mar 05, 2006 7:29 am Post subject: Lift Strut / Stress question

I'll check next time I go to the airport, but I believe it is a sleeve.



---

planecrazzzy
Guest

Posted: Sun Mar 05, 2006 8:01 am Post subject: Sleeves

Hey Guys,

               I thought "sleeves" only came in plastic....?



 If they make them in Aluminum...would they be easy to "slip over" my stock Lift Struts.....?



 I wouldn't want plastic sleeves , So ,I thought I would have to buy new Chromemoly inserts and remake my Streamline Aluminum Lift Struts....

                  Gotta Fly...

                                  Mike in MN

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sun Mar 05, 2006 9:06 am Post subject: Re: Lift Strut / Stress question

Are there problems with the chromemoly struts ??   This is a question that I asked Kolb when I bought my MK III and they said the chromemoly round struts were stronger and more tolerant of negative G's than the streamlined struts.



What have you guys experienced, do the round struts stake themselves to death over time ?  Are the streamlined struts better in the long run ?



Michael A. Bigelow

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

herbgh

Joined: 10 Jan 2006
Posts: 145

Posted: Sun Mar 05, 2006 9:42 am Post subject: Lift Strut / Stress question

Guys

   Haven't we discovered , over the years, that normally operated Kolbs

have never had a structural failure?      Herb ---MkIII,Ultrastar and

Firefly owner.. not at the same time!!   

On Sun,  5 Mar 2006 09:06:27 -0800 "JetPilot" <orcabonita(at)hotmail.com>

writes:

 	  Quote: 	
		   

 

 Are there problems with the chromemoly struts ??   This is a 

 question that I asked Kolb when I bought my MK III and they said the 

 chromemoly round struts were stronger and more tolerant of negative 

 G's than the streamlined struts.

 

 What have you guys experienced, do the round struts stake themselves 

 to death over time ?  Are the streamlined struts better in the long 

 run ?

 

 Michael A. Bigelow

 

 --------

 NO FEAR -  If you have no fear you did not go as fast as you could 

 have !!!

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=19688#19688

planecrazzzy
Guest

Posted: Sun Mar 05, 2006 9:49 am Post subject: Re: Lift Strut / Stress question

Hi JP,

        I don't know about Chromemoly Lift struts.....Mine are Stock Lift Struts.....Aluminum tube-inside an Aluminum tube....Then Chromemoly bolted on each end..... "MINE" wiggled and shook from time to time ,while I was flying.....I don't like that, so I'll be switching over to the Aluminum Streamline Lift Struts with the Chromemoly inserts like I already have...



 And that is why I was questioning the holes in the lift strut in that picture.

"I" think the Streamline Struts are STRONGER....But, their still going to go thru SOME flexing ...



 The problem with the Chromemoly on the Lift Struts that "I've" heard on THIS list.....Is, Some of them have been found with Cracks.....Didn't one guy "go down" because the lower chromemoly piece had weakened because of WATER , and then Failed in Flight....

 



 I've Sheared tubing for lattus on Crane Booms ....Sometimes when the metal had a little more tensil strength the end of the tube would "split" when Sheared.....If this happened it would get repaired....but the rest of the Stock would still have the potential to do the same thing.....We don't know if Kolb is "seeing" any of this when they go thru the process....

   When I've heard of cracks in the material, Thats where "I" think they were from....It just took alot of FLEXING to bring it out...



               Gotta Fly...

                               Mike in MN

 	  JetPilot wrote: 	
		  Are there problems with the chromemoly struts ??   This is a question that I asked Kolb when I bought my MK III and they said the chromemoly round struts were stronger and more tolerant of negative G's than the streamlined struts.



What have you guys experienced, do the round struts shake themselves to death over time ?  Are the streamlined struts better in the long run ?



Michael A. Bigelow

planecrazzzy
Guest

Posted: Sun Mar 05, 2006 10:02 am Post subject: Re: Lift Strut / Stress question

Bliss,

        Operated , Stock , Modified.....NEVER?  Are you Asking or Telling...



     Gotta Fly...

 	  herbgh wrote: 	
		  Guys

   Haven't we discovered , over the years, that normally operated Kolbs

have never had a structural failure?     Herb 

 	  Quote: 	
		   

 



 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=19688#19688

ElleryWeld(at)aol.com
Guest

Posted: Sun Mar 05, 2006 6:59 pm Post subject: Lift Strut / Stress question

I have swiched to the streamline struts on my firestar because all that 

movement, vibration in the old round ones made me nervous  and the streamline 

struts dont move at all and there less drag 

only my opinion take it for what you paid for it



Ellery in Maine Original Firestar changed a bit )



do not archive

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sun Mar 05, 2006 7:17 pm Post subject: Re: Lift Strut / Stress question

Thanks Mike,



The lift struts is something I have not really put much thought into.  I was going to put a Jury Strut on my MK-III like John Hauck did, but when I talked to Kolb they told me that the new struts were quite a big stronger and that it would not be needed.  I did not do any further research on this topic since then...



I will have one of the faster MK-III's built,  with the 912-S, the very efficient Kiev Hot prop, and wheel pants it should be pushing the airspeed limits.   Has anyone ever seen these vibrations in the round lift struts in a MK-III Xtra at high speeds ???   



Michael A. Bigelow

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

pj.ladd(at)btinternet.com
Guest

Posted: Mon Mar 06, 2006 6:43 am Post subject: Lift Strut / Stress question

I will have one of the faster MK-III's built,  with the 912-S, the very 

efficient Kiev Hot prop, and wheel pants it



Hi Mike,

what would that speed be in the US?  Here, with a Jabiru the Xtra is 

placarded at 95 pmh.



Pat



do not archive 



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