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AW: G Load testing

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uvtreith(at)t-online.de
Guest

Posted: Sat Jul 27, 2013 2:42 am Post subject: AW: G Load testing

Hi Craig,  

   

It is a must in Germany and other countries to do a positive static g-load test. You have to support the fuselage very strong and rigid with the bottom upwards.  

You install the wings level and measure the distance of the wing tips to the floor (using a mixing stick, taped on the wing tip.)  

Then you have to put weight on (sand sacks or cement sacks with 25 kg each) in an exactly definite position and in three steps, so at the end you will get the full load as required and in the correct position on the wings. After each (loading) step you have to measure the distance from the wingtip end to the floor.  

After these three steps you remove the load and measure again to get the setting difference of the whole plain before and after the loading procedure.  

With this test we demonstrate the maximum wing load. We do not do flying load tests as the results can get worse (accident Miles/Sweeting). We have got also wing load tests which failed do to not proper made fuselage.   

   

Believe me, when you do this test in the very late phase and you can hear the noise and cracking sound of the fuselage setting and the fuselage is still ok after this, the next some pints of bitter are tasting terrific good.  Attached are some info about the set up and procedure of the wing load and tailwing load test.  

If you need more info, please let me know.  

   

Safe and happy flying,  

   

Bruno    

   

   

   

-----Ursprüngliche Nachricht-----

 Von: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] Im Auftrag von craig

 Gesendet: Samstag, 27. Juli 2013 01:00

 An: europa-list(at)matronics.com

 Betreff: G Load testing  

   

--> Europa-List message posted by: "craig" <craigb(at)onthenet.com.au>  

   

I have seen a few photos on the group over the years with  

a/c inverted and bags of sand, concrete, gold coins etc stacked  

evenly on the wings to simulate the G loading, question is how are  

people supporting the weight for this test through the fuselage itself  

obviously the top of the cockpit would be insufficient to take such a load  

of what 8000+ pounds, assuming 6g x 1370lb, or do I have the math wrong on  

this  

   

my thoughts were it may be easier to keep the A/C upright and load the  

weight   

into the cockpit with the whole lot supported by cradle and a few extra  

supports under each wing

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clivesutton

Joined: 23 Jan 2013
Posts: 187
Location: KENILWORTH

Posted: Sat Jul 27, 2013 3:24 am Post subject: Re: AW: G Load testing

Bruno,

Thanks for your post -we can trust a German to provide some excellent detail!  That photo gives me great confidence in the design - they are bags of cement?  

Clive

paul.the.aviator(at)gmail
Guest

Posted: Sat Jul 27, 2013 7:34 am Post subject: AW: G Load testing

Does anyone have any photos that show the entire wing under load where I can see the deflection?

On Sat, Jul 27, 2013 at 6:24 AM, gtagr <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)> wrote:

 [quote]--> Europa-List message posted by: "gtagr" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>

  

 Bruno,

 Thanks for your post -we can trust a German to provide some excellent detail!  That photo gives me great confidence in the design - they are bags of cement?

 Clive 

 

 

 

 

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John Wighton

Joined: 18 May 2010
Posts: 242

Posted: Sun Jul 28, 2013 2:02 am Post subject: Re: AW: G Load testing

The issue of load testing should be approached very carefully.  as a30+ experienced aeronautical engineer, Chief of Stress at Pilatus Aircraft hopefully l can assist with a few pointers.



The design load level LIMIT loading is determined from the certification basis (or approval basis)  of the aircraft.  For LAA projects this is likely to be +4/-2, without the consideration of gusts.  The VN diagram submitted by Europa for the original will be basis that needs to be used.



Additional factors applicable will include the ULTIMATE factor, usually 1.5, Special Factors, these could include a factor for composites (usually negotiated as 1.5 to account for hot humid material property degradation), plus others that are agreed with the approving/certifying agency.



For a wing bending test, which is important but NOT the only test that is required, the calculation for total load would be 621kg x 4 x1.5 x1.5 - (wing mass).  The wing mass can be left on and is conservative).



This makes a total mass of 5590kg or 2790kg per wing for Europa XS.



The next step is to determine the spanwise and chordwise distribution of this load.  There are many issues to be considered here, however, a justification of the distribution used, coupled with the correct angle of attach, is sufficient.



Other cases with loader total loading may be more critical, such as torsional cases driven by manoeuvre control inputs or flap loads should also be considered.



Typically for an aircraft of the Europa class the load calcs take around 200-1000hrs.  A test plan to cover the critical ones needs to be created and submitted for approval (and often observation) by the authorities.



It is normal to correlate test data with predictive calculations (done using a combination of finite element models and hand calcs).  Hence the test is normally a confirmation of the predicted structural performance (deformed shape, stress/strain levels, failure locations if ULT+ loads are applied.



A light aircraft design and certification can absorb many 10,000 of man hours.  Typically around 20 to 50 times the retail price of the aircraft (rough guide as the cost curve is exponential).  Making the design certification cost of a 750kg VLA around  Â£2 to Â£5 million.



Hopefully this has been useful to someone?



Regards

John

_________________
John Wighton
Europa XS trigear G-IPOD

John Wighton

Joined: 18 May 2010
Posts: 242

Posted: Sun Jul 28, 2013 2:06 am Post subject: Re: AW: G Load testing

Incidentally l counted 43 bags per wing at 25kg per bag making a per wing total of 1075kg, loaded to 38% ULT.  



Which identifies the normal issues, the loading method is not appropriate for the required mass.  A higher density material or a whiffle tree is required.



Regards

JW

_________________
John Wighton
Europa XS trigear G-IPOD

craigb(at)onthenet.com.au
Guest

Posted: Sun Jul 28, 2013 1:22 pm Post subject: AW: G Load testing

Thanks john



this



"For a wing bending test, which is important but NOT the only test that is

required, the calculation for total load would be 621kg x 4 x1.5 x1.5 -

(wing mass).  The wing mass can be left on and is conservative).



This makes a total mass of 5590kg or 2790kg per wing for Europa XS."



Is more or less what I was expecting, I take it the extra 1.5 multiplier is

for the

Composite factor you mentioned



Regards

craig

John Wighton

Joined: 18 May 2010
Posts: 242

Posted: Mon Jul 29, 2013 2:31 am Post subject: Re: AW: G Load testing

Craig,

Yes 1.5 special factor.  Mitigation of this can be justified by performing hot wet tests which typically result in lower factors.  But can quickly escalate into difficult discussion unless correct testing methods, batch numbers and such like are adopted.



There are databases of data available for composites (NCAMP) for example which can also be used to justify reduced factors.  Not sure if the composites system that Europa use is in there.  



For Certification purposes we cover a temperature range -55 to +80 (typ).



Regards

John

_________________
John Wighton
Europa XS trigear G-IPOD

wdaniell.longport(at)gmai
Guest

Posted: Mon Jul 29, 2013 7:53 am Post subject: AW: G Load testing

What does the forum think of the value of this exercise?

 

Will

 

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of UVTREITH

Sent: Sunday, July 28, 2013 06:34

To: europa-list(at)matronics.com

Subject: AW: Re: AW: G Load testing

 

Hi Paul,

 

Here are some pictures.

02+04 is preparation with a soft foam blanket on which we also marked the position of the concrete bags, each 25 kg. 07 shows the support winches, which you can release very slowly and jumpless

15 shows the measurement after each load increase, 16+17 the full load of each side and 21 the full load spread. 

Each side 1035 kg concrete bags, therefore 2.070 kg in total. To this you have to add the wing weight of 94-100 kg complete, depends on build. 

The winches were released free (you can see it on the loose foam supports). One problem was that the support timber sticks were too short, so that we had to do some work on the wing surface later.

A similar test was also done with the tail plane 100 to 150 kg and opposite (pictures 9839, 9842 and 9845

With picture 9854 you can see, that this load test on a classic one failed. The fuselage/cockpit was not correct made and the fuse started to bulk out. This was later repaired and than ok. 

This is the wing load test, approved by the OUV and LBA here in Germany

 

 

 

Bruno

 

 



Von: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] Im Auftrag von Paul McAllister

Gesendet: Samstag, 27. Juli 2013 17:34

An: europa-list(at)matronics.com (europa-list(at)matronics.com)

Betreff: Re: Re: AW: G Load testing



 

Does anyone have any photos that show the entire wing under load where I can see the deflection?



 

On Sat, Jul 27, 2013 at 6:24 AM, gtagr <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)> wrote:

--> Europa-List message posted by: "gtagr" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>



Bruno,

Thanks for your post -we can trust a German to provide some excellent detail!  That photo gives me great confidence in the design - they are bags of cement?

Clive 





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=405403#405403



===========

target="_blank">http://www.matronics.com/Navigator?Europa-List

===========

http://forums.matronics.com

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

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  [quote][b]

kheindl(at)msn.com
Guest

Posted: Mon Jul 29, 2013 8:03 am Post subject: AW: G Load testing

Will wrote:

What does the forum think of the value of this exercise?

 

I don't know what to think and am totally confused. The required weights quoted per wing seem to range from 1000 to 2700 kilos. So was the original load test inadequate ?

Karl

 

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of UVTREITH

Sent: Sunday, July 28, 2013 06:34

To: europa-list(at)matronics.com

Subject: AW: Re: AW: G Load testing

 

Hi Paul,

 

Here are some pictures.

02+04 is preparation with a soft foam blanket on which we also marked the position of the concrete bags, each 25 kg. 07 shows the support winches, which you can release very slowly and jumpless

15 shows the measurement after each load increase, 16+17 the full load of each side and 21 the full load spread. 

Each side 1035 kg concrete bags, therefore 2.070 kg in total. To this you have to add the wing weight of 94-100 kg complete, depends on build. 

The winches were released free (you can see it on the loose foam supports). One problem was that the support timber sticks were too short, so that we had to do some work on the wing surface later.

A similar test was also done with the tail plane 100 to 150 kg and opposite (pictures 9839, 9842 and 9845

With picture 9854 you can see, that this load test on a classic one failed. The fuselage/cockpit was not correct made and the fuse started to bulk out. This was later repaired and than ok. 

This is the wing load test, approved by the OUV and LBA here in Germany

 

 

 

Bruno

 

 



Von: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] Im Auftrag von Paul McAllister

Gesendet: Samstag, 27. Juli 2013 17:34

An: europa-list(at)matronics.com (europa-list(at)matronics.com)

Betreff: Re: Re: AW: G Load testing



 

Does anyone have any photos that show the entire wing under load where I can see the deflection?



 

On Sat, Jul 27, 2013 at 6:24 AM, gtagr <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)> wrote:

--> Europa-List message posted by: "gtagr" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>



Bruno,

Thanks for your post -we can trust a German to provide some excellent detail!  That photo gives me great confidence in the design - they are bags of cement?

Clive 





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=405403#405403



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target="_blank">http://www.matronics.com/Navigator?Europa-List

===========

http://forums.matronics.com

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

===========



 

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[b]

paul.the.aviator(at)gmail
Guest

Posted: Mon Jul 29, 2013 12:03 pm Post subject: AW: G Load testing

Hi Bruno, thanks very much for the photos and documents. - Regards, Paul

On Sun, Jul 28, 2013 at 6:33 AM, UVTREITH <uvtreith(at)t-online.de (uvtreith(at)t-online.de)> wrote:

 [quote]                

Hi Paul,  

   

Here are some pictures.  

02+04 is preparation with a soft foam blanket on which we also marked the position of the concrete bags, each 25 kg. 07 shows the support winches, which you can release very slowly and jumpless  

15 shows the measurement after each load increase, 16+17 the full load of each side and 21 the full load spread.   

Each side 1035 kg concrete bags, therefore 2.070 kg in total. To this you have to add the wing weight of 94-100 kg complete, depends on build.   

The winches were released free (you can see it on the loose foam supports). One problem was that the support timber sticks were too short, so that we had to do some work on the wing surface later.  

A similar test was also done with the tail plane 100 to 150 kg and opposite (pictures 9839, 9842 and 9845  

With picture 9854 you can see, that this load test on a classic one failed. The fuselage/cockpit was not correct made and the fuse started to bulk out. This was later repaired and than ok.   

This is the wing load test, approved by the OUV and LBA here in Germany  

   

   

   

Bruno  

   

         

  

Von: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] Im Auftrag von Paul McAllister

 Gesendet: Samstag, 27. Juli 2013 17:34

 An: europa-list(at)matronics.com (europa-list(at)matronics.com)

 Betreff: Re: Re: AW: G Load testing  

  

     

Does anyone have any photos that show the entire wing under load where I can see the deflection?  

    

     

On Sat, Jul 27, 2013 at 6:24 AM, gtagr <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)> wrote:  

--> Europa-List message posted by: "gtagr" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>

 

 Bruno,

 Thanks for your post -we can trust a German to provide some excellent detail!  That photo gives me great confidence in the design - they are bags of cement?

 Clive 

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=405403#405403

 

 

 

 

 

 

 

 ===========

 target="_blank">http://www.matronics.com/Navigator?Europa-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

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