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Texas Parasol Plans...



 
 
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  #71  
Old March 1st 06, 07:49 PM posted to rec.aviation.homebuilt
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clare at snyder.on.ca wrote ...
It WAS attatched. It was attatched as if it was on the plane but
upside down.


I'd like to take a look at the deflections for this wing from a theoretical
veiwpoint. This discussion seems to have been on-going from another group.
Which group? What was the final loading and deflections when the test was
called off? Did the wing that was tested have the inserts as shown in the
current plans or was this an earlier wing without them?

Thanks

Rich


  #72  
Old March 1st 06, 08:51 PM posted to rec.aviation.homebuilt
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On Tue, 28 Feb 2006 09:50:32 -0500, Curtis Scholl
wrote:

Clare wrote:

"No- Gary built a wing according to plans and sandbag tested it under
an engineer's supervision. The engineer stopped the loading before
failure because of excessive deflection IIRC."
**


As you said, Clare, you are not an engineer. And you don't have current
validated DATA to back you up. I have stated instances of you being
incorrect in your assumptions. And in one of the instances, given you
the reference for corrections of your statements.




Just an update on the testing procedure and results on the TP wing
tested at Kitchener Waterloo International Airport last year.

The wing was instrumented with strain guages. The main spar was
bending significantly between the Cabane mounting and the strut, and
the strain readings were beyond the limits the engineer was
comfortable with at 2Gs testing for a 600 lb plane.Failure was
IMMINENT.
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  #73  
Old March 1st 06, 10:18 PM posted to rec.aviation.homebuilt
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Morgans wrote:
clare at snyder.on.ca wrote


Just an update on the testing procedure and results on the TP wing
tested at Kitchener Waterloo International Airport last year.

The wing was instrumented with strain guages. The main spar was
bending significantly between the Cabane mounting and the strut, and
the strain readings were beyond the limits the engineer was
comfortable with at 2Gs testing for a 600 lb plane.Failure was
IMMINENT.



I don't understand why the testing did not continue. Seems to me that
having someone say that failure was imminent, based on strain gauges, leaves
a lot of room for opinion to creep in.


Somehow, I get the impression that they would not have approved of Voyager's
wings either.


FWIW.

Richard
  #74  
Old March 1st 06, 10:31 PM posted to rec.aviation.homebuilt
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clare at snyder.on.ca wrote

Just an update on the testing procedure and results on the TP wing
tested at Kitchener Waterloo International Airport last year.

The wing was instrumented with strain guages. The main spar was
bending significantly between the Cabane mounting and the strut, and
the strain readings were beyond the limits the engineer was
comfortable with at 2Gs testing for a 600 lb plane.Failure was
IMMINENT.


I don't understand why the testing did not continue. Seems to me that
having someone say that failure was imminent, based on strain gauges, leaves
a lot of room for opinion to creep in.
--
Jim in NC

  #75  
Old March 1st 06, 11:42 PM posted to rec.aviation.homebuilt
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On Wed, 1 Mar 2006 16:31:13 -0500, "Morgans"
wrote:


clare at snyder.on.ca wrote

Just an update on the testing procedure and results on the TP wing
tested at Kitchener Waterloo International Airport last year.

The wing was instrumented with strain guages. The main spar was
bending significantly between the Cabane mounting and the strut, and
the strain readings were beyond the limits the engineer was
comfortable with at 2Gs testing for a 600 lb plane.Failure was
IMMINENT.


I don't understand why the testing did not continue. Seems to me that
having someone say that failure was imminent, based on strain gauges, leaves
a lot of room for opinion to creep in.

They didn't want to have to shovel up the sand when the sandbags
split on the floor.
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  #76  
Old March 2nd 06, 01:54 AM posted to rec.aviation.homebuilt
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clare at snyder.on.ca wrote:

On Wed, 1 Mar 2006 16:31:13 -0500, "Morgans"
wrote:


clare at snyder.on.ca wrote

Just an update on the testing procedure and results on the TP wing
tested at Kitchener Waterloo International Airport last year.

The wing was instrumented with strain guages. The main spar was
bending significantly between the Cabane mounting and the strut, and
the strain readings were beyond the limits the engineer was
comfortable with at 2Gs testing for a 600 lb plane.Failure was
IMMINENT.


I don't understand why the testing did not continue. Seems to me that
having someone say that failure was imminent, based on strain gauges,
leaves a lot of room for opinion to creep in.

They didn't want to have to shovel up the sand when the sandbags
split on the floor.



I don't have much interest on either side of this but have been reading with
curiosity. This last statement was really very lame! If someone's purpose
was to prove a design was deficient you would have thought they have tested
to failure. I doesn't cost alot to get a couple high school kids to do the
shoveling.
My question, How much permanent deflection in the wings after the test?
John

  #77  
Old March 2nd 06, 04:17 AM posted to rec.aviation.homebuilt
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clare at snyder.on.ca wrote

They didn't want to have to shovel up the sand when the sandbags
split on the floor.


IF that is really the reason, IMHO, that is pretty damn sorry.
--
Jim in NC
  #78  
Old March 2nd 06, 04:46 AM posted to rec.aviation.homebuilt
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On Wed, 1 Mar 2006 22:17:13 -0500, "Morgans"
wrote:


clare at snyder.on.ca wrote

They didn't want to have to shovel up the sand when the sandbags
split on the floor.


IF that is really the reason, IMHO, that is pretty damn sorry.


Look, I was not there when the test was done, but I know the guys who
were. I know the engineer who instrumented the test.

The shovelling was in jest. From what I understand, they were hoping
to make some modifications to the wing to make it a better wing, so
did not test to destruction. After doing more analysis they decided to
cut their losses and forget the project. They designed an all metal
wing, which MAY eventually be used on a TP-ish plane.

The strain guage information, along with the distortion under load was
adequate information to tell the engineer "enough"
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  #79  
Old March 2nd 06, 04:27 PM posted to rec.aviation.homebuilt
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Earlier, UltraJohn wrote:

My question, How much permanent
deflection in the wings after the test?


I think that that is one of the most central questions in this
exchange. If there was no permanant deflection, then the material never
reached its 35 ksi (some books like Machinery's Handbook say 40 ksi)
yield stress, and without deflection records we'll never really know
how close the test wing came to actually failing.

Overall, I'm satisfied with the descriptions that a fairly valid static
test was done. However, I know from watching videos of static tests and
from running deflection estimates for various wings that tests even to
just the design limit can result in some seriously spooky deflections.
And to add to that, the spar under consideration here is very shallow,
and that will also tend to give it a lot of deflection.

One thing I would have expected for a test like this is a comparison
between the wing under test and some sort of deflection reference like
a template. Since the spar in this case has a constant depth of 2", the
same template can be applied anywhere on the spar to check the
deflection and deduce the stress from that.

If I've run the numbers right, for a 2" tall aluminum (Young's modulus
of 10 meg) element, at 35 KSI in the extreme fibers the element will
have a curvature radius of about 20 feet. That may sound like a pretty
shallow curve, but over four feet it results in a bend of about 9.5
degrees and a vertical deflection of about 4".

But don't take my word for it, I'm _not_ an engineer...

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

  #80  
Old March 4th 06, 07:00 AM posted to rec.aviation.homebuilt
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SNIP
I don't understand why the testing did not continue. Seems to me that
having someone say that failure was imminent, based on strain gauges,
leaves
a lot of room for opinion to creep in.

They didn't want to have to shovel up the sand when the sandbags
split on the floor.


That was a stupid childish answer.

I would say Mr Scholl kicked butt with facts.


 




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