KR> center spar analysis

[Rogelio M. Serrano Jr.]

Based on a section modulus of 18.5 in3 and yield strength of spruce at 5000
Psi, the center spar should yield at 92500 lb in. bending moment. I don't
know how that translates to wing load.

On Feb 22, 2015 4:58 PM,  wrote:
>
> Just an idea. We have a gathering coming up in September.  I would
imagine there is a set of fwd spars lying around gathering dust somewhere.
If we can get them to McMinnville with some sandbags and do our on test. I
would be willing to pitch in to help defray the cost.
>
> I might be able to talk to Eric at Wicks to donate some of there
scrap spruce if someone would like to build a AS5048 Spar. We would just
need a center and one outboard spar.
>
> Paul Visk
> Belleville Il.
> 618-406-4705
>
> In a message dated 2/22/2015 10:23:07 A.M. Central Standard Time,
krnet at list.krnet.org writes:
>>
>> On Sun, Feb 22, 2015 at 1:29 AM, Flesner via KRnet 
wrote:
>> >
>> >>
>> >> The Spreadsheet says we should be using aluminum spars to make more
>> >> than 2G load factors.
>> >
>> > 
>> >
>> > It's been a long held belief that the WAF's were the weak point in the
KR
>> > spars.  I've had the opportunity to inspect 3 crashed KR's,
unfortunately
>>
>> both front and rear spars together can easily take 3.8G at 1200 lbs
>> mtow. but thats a rough calculation. i'm actually overestimating the
>> stresses because tapered wings have more or less 10% lower bending
>> moments than rectangular wings overall. I was assuming a rectangular
>> wing.
>>
>> a more accurate computation will require more accurate load
>> distributions with flap and aileron deflections considered. only
>> shrenk's approximation and similar procedures can do that.
>>
>> ___
>> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
>> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
>> please see other KRnet info at http://www.krnet.org/info.html
>> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to
change options

KR> wrench?

[Flesner]

>
> > Does anyone manufacture a ratcheting, open end  wrench?
++

Thanks to all that replied.  I should have done some "googleing" 
before asking the question.

Larry Flesner  

KR> wrench?

[Mark Langford]

Larry Flesner wrote:

 > Does anyone manufacture a ratcheting, open end  wrench?

Sears sells the Craftsman #914755 set (SAE), and there's a metric 
version as well.  They ratchet on both the box end and the open end. 
They were pretty cheap for Christmas and have gone up a bit, but still 
only $39.96 now.  I couldn't resist one of each back at Christmas. See
http://www.sears.com/craftsman-8-pc-inch-dual-ratcheting-wrench-set/p-00914755000P?sid=IDx01192011x01&kpid=00914755000&kispla=00914755000P&kpid=00914755000&mktRedirect=y
 
, if you can cut and paste it all in, or just search for "sears 
craftsman 914755" and 914756 (metric).

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> center spar analysis. Just an idea. (Repost sorry)

[Rogelio M. Serrano Jr.]

That would be great!

On Feb 22, 2015 6:07 PM, "Paul-Visk via KRnet"  wrote:
>
>
> Just an idea. We have a gathering coming up in September.  I would
imagine
> there is a set of fwd spars lying around gathering dust  somewhere.  If we
> can get them to McMinnville with some  sandbags and do our on test. I
would
> be willing to pitch in to  help defray the cost.
>
> I might be able to talk to Eric at Wicks to donate some of there  scrap
> spruce if someone would like to build a AS5048 Spar. We would  just need a
> center and one outboard spar.
>
> Paul  Visk
> Belleville Il.

KR> wrench?

[Peter Johnson]

Canadian Tire here in Canada sells their 'Mastercraft' brand.

I'm sure somebody somewhere in the states sells the same idea.


Peter Johnson
Kenora, Ontario.



- Original Message - 
From: "Flesner via KRnet" 
To: 
Sent: Sunday, February 22, 2015 5:22 PM
Subject: KR> wrench?


>
>
> Does anyone manufacture a ratcheting, open end  wrench?  If not someone 
> needs to and I'd only ask 5 percent commission for the idea.
>
> Larry Flesner
>
>
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change 
> options 

KR> wrench?

[Flesner]

Does anyone manufacture a ratcheting, open end  wrench?  If not 
someone needs to and I'd only ask 5 percent commission for the idea.

Larry Flesner

KR> those pesky fiberglass splinters

[Peter Johnson]

Being involved with using the WEST system in large hull construction, I've 
found that one way to alleviate the itching is to get into as hot a shower 
as you can stand, and use a soft, plastic bristle brush and lots of soap to 
scrub as hard as you can.

Don't know if this so much removes the bities, but it does reduce their 
annoyance.


Peter Johnson
Kenora, Ontario





Subject: KR> those pesky fiberglass splinters


> Okay, so maybe it's just me but it seems like anytime I have a 
> freshly-cured layup or any fiberglass with a ragged edge and I brush up 
> against it, I've got those itchy invisible glass splinters in my skin and 
> no easy way to see them or get rid of them.  Scratching and scraping only 
> breaks them off and leaves parts buried in the skin, still irritating and 
> itching.  Slapping a piece of duct tape on the area will sometimes pull up 
> most of them, but here's a way to get them all.
>
> Get some white or yellow wood glue (Elmer's, Titebond, whatever...NOT 
> epoxy and NOT super glue!)  Spread a layer of it around on the area where 
> the glass splinters are.  Let it dry and then gently peel it off, starting 
> at the edge.  If it's good and dry, the glue will peel off in one piece 
> and the splinters will come up with the dried glue.  Works for those tiny 
> wood splinters, too.
>
> Oscar Zuniga
> Medford, OR

KR> center spar analysis

[Rogelio M. Serrano Jr.]

On Sun, Feb 22, 2015 at 1:29 AM, Flesner via KRnet  
wrote:
>
>>
>> The Spreadsheet says we should be using aluminum spars to make more
>> than 2G load factors.
>
> 
>
> It's been a long held belief that the WAF's were the weak point in the KR
> spars.  I've had the opportunity to inspect 3 crashed KR's, unfortunately

both front and rear spars together can easily take 3.8G at 1200 lbs
mtow. but thats a rough calculation. i'm actually overestimating the
stresses because tapered wings have more or less 10% lower bending
moments than rectangular wings overall. I was assuming a rectangular
wing.

a more accurate computation will require more accurate load
distributions with flap and aileron deflections considered. only
shrenk's approximation and similar procedures can do that.

KR> seat belts...

[Dan Heath]

This is how I did it.  On my first KR, I attached the shoulder straps to
cables running back to the tail wheel.  I then heard of someone almost
getting strangled with them in an accident where the tail was sheared off,
so came up with this solution.  In the incident after the 2013 Gathering,
which was a "semi crash" the belts saved me from virtually any bodily harm.

http://krbuilder.org/SeatBelts/index.html


My Panther Building Documentation at PantherBuilder Web Site

Daniel R. Heath -?Lexington, SC

-Original Message-

Where and how have some of you attached/installed seat belts and shoulder
harness?

KR> wrench?

[Dan Prichard]

They do. Opened end ratchet set. $20.00 husky brand. Home Depot.  Wouldn't be 
caught without mine. 

Dan Prichard
Portland, Or

Sent from my iPhone

> On Feb 22, 2015, at 3:22 PM, Flesner via KRnet  
> wrote:
> 
> 
> 
> Does anyone manufacture a ratcheting, open end  wrench?  If not someone needs 
> to and I'd only ask 5 percent commission for the idea.
> 
> Larry Flesner
> 
> 
> ___
> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search.
> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org
> please see other KRnet info at http://www.krnet.org/info.html
> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change 
> options

KR> those pesky fiberglass splinters

[Oscar Zuniga]

Okay, so maybe it's just me but it seems like anytime I have a freshly-cured 
layup or any fiberglass with a ragged edge and I brush up against it, I've got 
those itchy invisible glass splinters in my skin and no easy way to see them or 
get rid of them.  Scratching and scraping only breaks them off and leaves parts 
buried in the skin, still irritating and itching.  Slapping a piece of duct 
tape on the area will sometimes pull up most of them, but here's a way to get 
them all.

Get some white or yellow wood glue (Elmer's, Titebond, whatever...NOT epoxy and 
NOT super glue!)  Spread a layer of it around on the area where the glass 
splinters are.  Let it dry and then gently peel it off, starting at the edge.  
If it's good and dry, the glue will peel off in one piece and the splinters 
will come up with the dried glue.  Works for those tiny wood splinters, too.

Oscar Zuniga
Medford, OR

KR> seat belts...

[Mark Langford]

GaryH wrote:

 > Where and how have some of you attached/installed seat belts and shoulder
 > harness?

One way to anchor the shoulder belts (a retrofit if you can't get any 
further back) is shown at http://www.n56ml.com/n891jf/harness/ , 
although N56ML's were cables wrapped around the two vertical stab spars 
and nicopressed, then Y'd out about three feet aft of the shoulders to 
capture both belts for each passenger.

Seat belts on both planes are aluminum angles located on the aft face 
about 3/16" thick bolted through the upper aft spar cap.  I bolted the 
belts to the angles (and cable eyes, in the case of the belts) with 
5/16" bolts, just to match the seat belt's anchor points.

Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> seat belts...

[Flesner]

At 02:05 PM 2/22/2015, you wrote:
>Where and how have some of you attached/installed seat belts and shoulder
>harness?
>Gary


I made the brackets in the photo 
http://myplace.frontier.com/~flesner/fittings.jpg to locate the belt 
attach point forward of the rear spar and slightly elevated.  This 
places the attach points in a better location to hold you down as 
well as back.  Attached directly to the rear spar would have you held 
primarily from moving forward, little help in holding you down to the 
seat.  I copied the idea from another KR seen at one of the 
Gatherings  My shoulder belt attach points are less than ideal as 
attached to the upper seat back support.  Others have cables to the 
rear of the fuselage and is a better setup.

Larry Flesner  

KR> seat belts...

[GaryH]

Where and how have some of you attached/installed seat belts and shoulder
harness?



Gary



Soli Deo Gloria

KR> center spar analysis. Just an idea. (Repost sorry)

[PPaulVsk at aol.com]

Just an idea. We have a gathering coming up in September.  I would  imagine 
there is a set of fwd spars lying around gathering dust  somewhere.  If we 
can get them to McMinnville with some  sandbags and do our on test. I would 
be willing to pitch in to  help defray the cost.  

I might be able to talk to Eric at Wicks to donate some of there  scrap 
spruce if someone would like to build a AS5048 Spar. We would  just need a 
center and one outboard spar. 

Paul  Visk
Belleville Il.
618-406-4705  


In a message dated 2/22/2015 10:23:07 A.M. Central Standard Time,  
krnet at list.krnet.org writes:

On Sun,  Feb 22, 2015 at 1:29 AM, Flesner via KRnet   
wrote:
>
>>
>> The Spreadsheet says we should be using  aluminum spars to make more
>> than 2G load  factors.

KR> test

[PPaulVsk at aol.com]

Did this get posted?  I'm not getting my own email posts and not  seeing 
them in the archives.

Paul  Visk
Belleville Il.
618-406-4705
_ppaulvsk at aol.com_ (mailto:ppaulvsk at aol.com) 

KR> center spar analysis

[Herbert Fürle]

Hello netters,over here in Germany ,I had to do a spar and WAF load test for my 
Kr.  Mr. Otto Bartsch from the OUV(the German association for experimentals and 
a aerodynamic ingeneer at Messerschmitt Boelkow Blohm (MBB) did a very simple 
but efficient Job.To demonstrate the strength of the spars he did not covered 
them with plywood.He also wanted  to see If the bolts would split the wood 
under high loads. The complete test was very successful. The very slightly bent 
on the WAF's ( pic far right) was the result of a not calculable load (more 
than 7 g's supposed by Otto Bartsch) caused by an aprupt stop of the loading 
shovel.To prevent this bending under very high loads,Otto Bartsch recommended  
to switch to an one bolt systhem.I hope that the documentation is instructive 
on the basis of the fotos .

Herbert F?rle,

Gemany Kr



https://www.dropbox.com/s/jvxw8xdz990kwn0/SWScan00013.BMP?dl=0



Von meinem iPad gesendet

KR> wheel, brake, and tire update

[Mark Langford]

KRnetHeads,

Although I should have been at the airport installing my "new" brakes 
yesterday, I hung around the house for a FedEx delivery (which never 
came) instead.  So I took the opportunity to update the brake webpage at
http://www.n56ml.com/n891jf/brakes/index.html#matco .  I think there's 
some useful info here, such as a brake, wheel, and tire comparisons, as 
well as one way to assemble wheels without pinching the tube.And you 
wonder why it takes me months to swap brakes...

-- 
Mark Langford
ML at N56ML.com
http://www.n56ml.com

KR> Subject: center spar analysis

[Pete and Karen Gauthier]

I checked my work in the morning!!  The real answere is...I=66.7 in4 
(2774.3cm4) so Z= 25.7 in3 (421.1cm3) does this sound more resonable?



Pete



 Original Message - 


From: Pete and Karen Gauthier 

To: krnet at list.krnet.org 

Sent: Saturday, February 21, 2015 7:10 PM

Subject: Subject: KR> center spar analysis





Has anyone tried computing the section modulus of the front center spar?


I should probably wait until tomorrow to check my work but I get I=36.7 in4 
(152.7cm4).  Z = I/c so Z= 10.2in3 (41.5cm3).   I used dimensions from my CAD 
drawings and they are before any trimming for the airfoil but I think the 
difference is insignificant.  Are these numbers close to what you got? Do I 
need to go back and do it over?



Pete

KR> Subject: center spar analysis

[Flesner]

>
>
>I should probably wait until tomorrow to check my work but I get 
>I=36.7 in4 (152.7cm4).  Z = I/c so Z= 10.2in3 (41.5cm3).
>Pete


And that means what in non-engineer speak?

Larry Flesner 

KR> center spar analysis

[Flesner]

At 07:41 PM 2/21/2015, you wrote:
>has the strength ever been questioned of this design, spars or 
>anything else?
+

Yes, many times by many people, especially the WAF's, but nothing to 
do with actual aircraft has indicated any structural weaknesses 
anywhere in the design.  Build it correctly, fly it with common 
sense, and you won't break it.

Larry Flesner 

KR> center spar analysis

[Flesner]

>  The complete test was very successful. The very slightly bent on 
> the WAF's ( pic far right) was the result of a not calculable load 
> (more than 7 g's supposed by Otto Bartsch)

+++

Was there some type of devise used to measure the actual loads 
applied to the test spar fittings?

Larry Flesner