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New Project Problems

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Afterfxllc(at)aol.com
Guest

Posted: Fri Apr 25, 2008 5:06 pm Post subject: New Project Problems

I just started building a new 601XL and last night I fitted the brakes and  mounted the axles and tires and that took about 3 hours but then I started the  mount the front fork to the main gear tube and looked at how far off the weld  is.... I am a bit concerned that the QC is not up to par. You would think they  would have a fixture made for this and they would be exact. I have added a link  to a couple pics of the off set between the steering rods and the nose  wheel fork.

  

 http://www.project601xl.com/New_Plane.html

  

 Jeff



Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

  [quote][b]

bobefx(at)yahoo.com
Guest

Posted: Fri Apr 25, 2008 5:44 pm Post subject: New Project Problems

Jeff, My point, Quality Control, it is vary lacking.

 '

 Bobefx

 ---

MHerder

Joined: 11 Feb 2008
Posts: 143
Location: Fort Worth TX

Posted: Fri Apr 25, 2008 7:42 pm Post subject: Re: New Project Problems

My personal experience is that I have not encountered ANY quality control issues thus far.  In fact every time that I have found an issue that I suspected was a QC issue I found that it was not after all.  I would consider myself to be pretty picky too. Very picky.  



But I will agree that perhaps your front gear is a little twisted.  I'd be willing to bet my paycheck that all you would have to do is contact Shirley, send a pic and you will have a new one in a week or less.

_________________
Zodiac 601 HD
Jabiru 3300
Wood Sensinich 64x47
Finally Flying

Afterfxllc(at)aol.com
Guest

Posted: Fri Apr 25, 2008 8:22 pm Post subject: New Project Problems

I'm not upset about it and I know Zenith will make it right and this is my  3rd 601 so been there done that but the point was that this is such a simple  welded piece that it should be dead on.

  	  Quote: 	
		  My    personal experience is that I have not encountered ANY quality control issues    thus far.  In fact every time that I have found an issue that I suspected    was a QC issue I found that it was not after all.  I would consider    myself to be pretty picky too. Very picky.  



But I will agree that    perhaps your front gear is a little twisted.  I'd be willing to bet my    paycheck that all you would have to do is contact Shirley, send a pic and you    will have a new one in a week or less. 	
  

 do not archive

  	  Quote: 	
		  

 	
 

  



Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

  [quote][b]

craig(at)craigandjean.com
Guest

Posted: Fri Apr 25, 2008 9:39 pm Post subject: New Project Problems

I've had two quality problems with my QBK, both acknowledged by the factory:



- The holes in the upper motor mount brackets did not align with the holes

in the firewall. They were off by 1/8 of an inch. Zenith sent me new,

undrilled motor mount brackets but they were of the new triangular style so

I had to do some rework.



- more seriously all four outer bolt holes in the center spare (two per

side) are 6 to 10 thousandths over. Because the other holes in the center

spar are within spec (and ALL the holes in the wing spare) is seem very

likely that the problem holes were enlarged when the holes in the spar

uprights (6B13-1) were line-drilled. The factory doesn't have a good fix for

this one. Roger quotes CH as saying that 12 thou is within spec but I don't

buy it. The plans called for all these holes to be precision reamed. Note

that because the corresponding holes in the wing spars are NOT oversized I

can't just use a larger bolt even if I could find one.



The only fix I can think of is to remove the center spar from the fuselage,

bolt it to each wing in turn and drill/ream the holes to 3/8ths. I don't

think it is feasible to do this with the center spar in the fuselage. But

another QBK builder is investigating that solution. Luckily I have had a lot

of practice drilling out rivets.



In a few years it will be interesting to look at quality issues (if any)

with Van's RV-12 and Ran's S-19.



BTW: the bottom plate on my front gear tube was square but shifted to one

side by a little under 1/8th of an inch.



-- Craig



--

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Sat Apr 26, 2008 3:37 am Post subject: Re: New Project Problems

I don't think I'd open the holes to 3/8. The spar caps (the 1/4 x 1.5inch bar) is already pretty close to minimum edge distance, even with the 5/16 bolts.



When I drilled my center spar to spar clamped everything together and first went in with a small hole and an alignment bolt, then another alignment bolt, then another small alignment bolt etc... then started opening up each hole and reaming. Took a few hours, but all the reamed holes line up nicely.



do not archive



 	  craig(at)craigandjean.com wrote: 	
		  I've had two quality problems with my QBK, both acknowledged by the factory:



- The holes in the upper motor mount brackets did not align with the holes

in the firewall. They were off by 1/8 of an inch. Zenith sent me new,

undrilled motor mount brackets but they were of the new triangular style so

I had to do some rework.



- more seriously all four outer bolt holes in the center spare (two per

side) are 6 to 10 thousandths over. Because the other holes in the center

spar are within spec (and ALL the holes in the wing spare) is seem very

likely that the problem holes were enlarged when the holes in the spar

uprights (6B13-1) were line-drilled. The factory doesn't have a good fix for

this one. Roger quotes CH as saying that 12 thou is within spec but I don't

buy it. The plans called for all these holes to be precision reamed. Note

that because the corresponding holes in the wing spars are NOT oversized I

can't just use a larger bolt even if I could find one.



The only fix I can think of is to remove the center spar from the fuselage,

bolt it to each wing in turn and drill/ream the holes to 3/8ths. I don't

think it is feasible to do this with the center spar in the fuselage. But

another QBK builder is investigating that solution. Luckily I have had a lot

of practice drilling out rivets.



In a few years it will be interesting to look at quality issues (if any)

with Van's RV-12 and Ran's S-19.



BTW: the bottom plate on my front gear tube was square but shifted to one

side by a little under 1/8th of an inch.



-- Craig



--

craig(at)craigandjean.com
Guest

Posted: Sat Apr 26, 2008 9:39 am Post subject: New Project Problems

Unlike rivets there is no hard and fast edge-distance for a bolt. The

factory has agreed that in principal that the hole can be upsized.



Going from 5/16th to 3/8th is an increase of 1/16th. The edges of the hole

will move half that or 1/32nd which is 31.25 thou. I'm comfortable with

loosing that much metal. Note that I would only have to do this to 4 of the

12 holes.



-- Craig



--

Afterfxllc(at)aol.com
Guest

Posted: Sat Apr 26, 2008 10:55 am Post subject: New Project Problems

Zenith told me that it isn't as much the bolt hole tolerance that is  critical but the clamping pressure of the bolt that is more important just like  the prop. I haven't had any problems with the spars on 3 kits but will check my  spars and center section before I install it in the plane. I also fixed the  front gear problem by shifting the fork about 1/8 inch it doesn't look all  the professional but the wheel pant will cover it.

  

 Jeff

 www.aeroliteproducts.com

 www.project601xl.com

  

  

  

  

 Unlike rivets there is no hard and fast edge-distance for a bolt.  The

factory has agreed that in principal that the hole can be  upsized.



Going from 5/16th to 3/8th is an increase of 1/16th. The edges  of the hole

will move half that or 1/32nd which is 31.25 thou. I'm  comfortable with

loosing that much metal. Note that I would only have to do  this to 4 of the

12 holes.



-- Craig



-----Original  Message-----

From:  owner-zenith-list-server(at)matronics.com

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

Sent: Saturday, April 26, 2008 5:37 AM

To:  zenith-list(at)matronics.com

Subject: Re: New Project  Problems



--> Zenith-List message posted by: "ashontz"  <ashontz(at)nbme.org>



I don't think I'd open the holes to 3/8. The  spar caps (the 1/4 x 1.5inch

bar) is already pretty close to minimum edge  distance, even with the 5/16

bolts.



When I drilled my center spar to  spar clamped everything together and first

went in with a small hole and an  alignment bolt, then another alignment

bolt, then another small alignment  bolt etc... then started opening up each

hole and reaming. Took a few hours,  but all the reamed holes line up nicely.



do not  archive

craig(at)craigandjean.com wrote:

 	  Quote: 	
		   I've had two quality  problems with my QBK, both acknowledged by the

factory:
	


 	  Quote: 	
		   

 -  The holes in the upper motor mount brackets did not align with the holes

  in the firewall. They were off by 1/8 of an inch. Zenith sent me new,

  undrilled motor mount brackets but they were of the new triangular  style

so
	


 	  Quote: 	
		   I had to do some rework.

 

 - more seriously  all four outer bolt holes in the center spare (two per

 side) are 6 to 10  thousandths over. Because the other holes in the center

 spar are within  spec (and ALL the holes in the wing spare) is seem very

 likely that the  problem holes were enlarged when the holes in the spar

 uprights (6B13-1)  were line-drilled. The factory doesn't have a good fix

for
	


 	  Quote: 	
		   this one.  Roger quotes CH as saying that 12 thou is within spec but I

don't
	


 	  Quote: 	
		   buy  it. The plans called for all these holes to be precision reamed. Note

  that because the corresponding holes in the wing spars are NOT oversized  I

 can't just use a larger bolt even if I could find one.

  

 The only fix I can think of is to remove the center spar from  the

fuselage,
	


 	  Quote: 	
		   bolt it to each wing in turn and drill/ream the holes  to 3/8ths. I don't

 think it is feasible to do this with the center spar  in the fuselage. But

 another QBK builder is investigating that solution.  Luckily I have had a

lot
	


 	  Quote: 	
		   of practice drilling out rivets.

  

 In a few years it will be interesting to look at quality issues (if  any)

 with Van's RV-12 and Ran's S-19.

 

 BTW: the bottom  plate on my front gear tube was square but shifted to one

 side by a  little under 1/8th of an inch.

 

 -- Craig

 

  --


	




--------

Andy Shontz

CH601XL -  Corvair

www.mykitlog.com/ashontz

 

  



Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

  [quote][b]

craig(at)craigandjean.com
Guest

Posted: Sat Apr 26, 2008 11:27 am Post subject: New Project Problems

 	  Quote: 	
		   Zenith told me that it isn't as much the bolt hole tolerance that is critical but the clamping pressure of the bolt that is more important just like the prop.  

   
	


They told me the same thing. But it is at odds with the requirement that the holes be precision reamed. On an RV-7 the equivalent holes are burnished. I’ve attached a close-up of a shot of Lance Gingell’s RV-7a spar. He is making great progress: http://lancegingell.blogspot.com/  

   

BTW: the only way I have found to get an accurate measurement on the hole sizes is to use plug gauges. I bought a set from Grizzly but Zenith has been loaning a handful of gauges near the correct size to other builders to check theirs.  

   

-- Craig

RV-7_spar.jpg

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n801bh(at)netzero.com
Guest

Posted: Sat Apr 26, 2008 4:34 pm Post subject: New Project Problems

The forces acting on that joint are in shear, not tension. A reamed hole is critical.  Period!!!! 

  

do not archive



  

 	  Quote: 	
		   Zenith told me that it isn't as much the bolt hole tolerance that is critical but the clamping pressure of the bolt that is more important just like the prop.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 

  
	


They told me the same thing. But it is at odds with the requirement that the holes be precision reamed. On an RV-7 the equivalent holes are burnished. I’ve attached a close-up of a shot of Lance Gingell’s RV-7a spar. He is making great progress: http://lancegingell.blogspot.com/ 

  

BTW: the only way I have found to get an accurate measurement on the hole sizes is to use plug gauges. I bought a set from Grizzly but Zenith has been loaning a handful of gauges near the correct size to other builders to check theirs. 

  

-- Craig

 



_____________________________________________________________

Prepare for the unexpected. Click now to prepare a living trust.

   [quote][b]

rsteele(at)rjsit.com
Guest

Posted: Sat Apr 26, 2008 6:21 pm Post subject: New Project Problems

Coming from a structures background, this seems completely backward, so I googled a bit and found that for aerospace applications, bolted connections are usually designed with bolts in shear - a no-no for structures.  I'm a curious as to why.  All the web pages I found that might talk about this require a membership.  Could you educate the group a bit on why aerospace connections rely on shear rather than clamping pressure, the norm for most applications?

do not archive

Ron



On Apr 27, 2008, at 12:28 AM, n801bh(at)netzero.com (n801bh(at)netzero.com) wrote:

[quote]

The forces acting on that joint are in shear, not tension. A reamed hole is critical.  Period!!!! 



do not archive



 

 	  Quote: 	
		   Zenith told me that it isn't as much the bolt hole tolerance that is critical but the clamping pressure of the bolt that is more important just like the prop.

 
	


They told me the same thing. But it is at odds with the requirement that the holes be precision reamed. On an RV-7 the equivalent holes are burnished. I’ve attached a close-up of a shot of Lance Gingell’s RV-7a spar. He is making great progress: http://lancegingell.blogspot.com/

 

BTW: the only way I have found to get an accurate measurement on the hole sizes is to use plug gauges. I bought a set from Grizzly but Zenith has been loaning a handful of gauges near the correct size to other builders to check theirs.

 

-- Craig

 



_____________________________________________________________

Prepare for the unexpected. Click now to prepare a living trust.

  	  Quote: 	
		  

href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronics.com/Navigator?Zenith-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/contribution



	
[b]

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Sun Apr 27, 2008 3:38 am Post subject: Re: New Project Problems

I wholely agree. The torque value/clamp force, has been dicussed here before. I still think under enough cycles, that spr will move a bit if not reamed. Movement leads to fatigue, leads to failure.



The plans call for reaming, yet they say it's not critical. Doesn't mkae sense, particularly for that joint. Reaming is the way to go.



[quote="n801bh(at)netzero.com"]The forces acting on that joint are in shear, not tension. A reamed hole is critical.  Period!!!! 

  

do not archive



  

 	  Quote: 	
		   Zenith told me that it isn't as much the bolt hole tolerance that is critical but the clamping pressure of the bolt that is more important just like the prop.<xml> 

  

	


They told me the same thing. But it is at odds with the requirement that the holes be precision reamed. On an RV-7 the equivalent holes are burnished. I?ve attached a close-up of a shot of Lance Gingell?s RV-7a spar. He is making great progress: http://lancegingell.blogspot.com/ 

  

BTW: the only way I have found to get an accurate measurement on the hole sizes is to use plug gauges. I bought a set from Grizzly but Zenith has been loaning a handful of gauges near the correct size to other builders to check theirs. 

  

-- Craig

 



_____________________________________________________________

Prepare for the unexpected. Click now to prepare a living trust.

    	  Quote: 	
		  [b]

planecrazydld(at)yahoo.co
Guest

Posted: Sun Apr 27, 2008 3:41 am Post subject: New Project Problems

Hi Ron;



I am not the originator of the message but the shear values are simply the minimum load transfer condition - and even then they only apply when the joint is burr free and sheared up. Face to face friction due to clamping is a major transfer component.



Usually, in certificated aircraft, when you see an ultimate failure, you usually see rows of rivets popped intermingled with sheet failure in and out of those rows of holes. The butts or heads of those rivets are many times still present on one side of the other.



Design of a riveted joint involves knowing the bearing strength of the component(s) to be joined and the shear and tension capabilities of the fastener. The pattern and fastyener diameter is selected to give as nearly even a failure mode split between fastener shear and sheet bearing. Since our fasteners depend to a very great deal on the work hardening of the fastener during setting, the hole size and quality are VERY important - and not  many people care about that anymore (or proper deburring) ...takes too long, is not critical, not building SSTs, etc.



Ronald Steele <rsteele(at)rjsit.com> wrote:[quote]  Coming from a structures background, this seems completely backward, so I googled a bit and found that for aerospace applications, bolted connections are usually designed with bolts in shear - a no-no for structures.  I'm a curious as to why.  All the web pages I found that might talk about this require a membership.  Could you educate the group a bit on why aerospace connections rely on shear rather than clamping pressure, the norm for most applications?

do not archive

Ron



On Apr 27, 2008, at 12:28 AM, n801bh(at)netzero.com (n801bh(at)netzero.com) wrote:

[quote]The forces acting on that joint are in shear, not tension. A reamed hole is critical.  Period!!!!

 

do not archive

 > Zenith told me that it isn't as much the bolt hole tolerance that is critical but the clamping pressure of the bolt that is more important just like the prop.

 

They told me the same thing. But it is at odds with the requirement that the holes be precision reamed. On an RV-7 the equivalent holes are burnished. I’ve attached a close-up of a shot of Lance Gingell’s RV-7a spar. He is making great progress: http://lancegingell.blogspot.com/

 

BTW: the only way I have found to get an accurate measurement on the hole sizes is to use plug gauges. I bought a set from Grizzly but Zenith has been loaning a handful of gauges near the correct size to other builders to check theirs.

 

-- Craig



 



_____________________________________________________________

Prepare for the unexpected. Click now to prepare a living trust.

 [quote]

href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronics.com/Navigator?Zenith-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/contribution



Be a better friend, newshound, and  [quote][b]

psm(at)att.net
Guest

Posted: Wed Apr 30, 2008 4:35 am Post subject: New Project Problems

Hi Ron,



Just a guess on my part  . . .



With aviation, the overwhelming characteristic of any design feature 

is how much it weighs.  A kit designer wrote in his newsletter a few 

decades ago - "If you are considering adding something to my design, 

throw it up in the air.  If it comes back down it is too heavy."



This may explain why aircraft bolts are some three times as strong as 

normal hardware store bolts and stronger than automotive bolts.  They 

cost more to make because of the alloys and machining difficulty, but 

they weigh less for similar performance.



When a bolt is used in shear mode, the strength comes primarily from 

the strength of the bolt rather than how well it is installed.  So 

long as it stays put, it does the job.  That makes this a somewhat 

more reliable connection than one that can be vibrated loose and fail 

more easily.  Indeed, you normally install aircraft bolts with the 

threads facing downward.  That means that even if the nut comes off 

the bolt still does its job in shear strength.



Airplanes must be light and highly reliable.  So my guess is the 

reason for use of aircraft bolts in the common practice of shear mode 

is done that way because it results in lighter and more reliable structures.



Paul

XL fuselage

do not archive

At 07:18 PM 4/26/2008, you wrote:

 	  Quote: 	
		  Coming from a structures background, this seems completely backward, 

so I googled a bit and found that for aerospace applications, bolted 

connections are usually designed with bolts in shear - a no-no for 

structures.  I'm a curious as to why.  All the web pages I found 

that might talk about this require a membership.  Could you educate 

the group a bit on why aerospace connections rely on shear rather 

than clamping pressure, the norm for most applications?



do not archive

Ron

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