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Frame Stress From High Winds


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Poll: Rev Arcana Poll Version 1.0 alpha (42 member(s) have cast votes)

Which parts of the Rev 1.5's frame are most apt to be riven asunder by the raw elemental fury of high winds?

  1. The vertical spars. (24 votes [55.81%])

    Percentage of vote: 55.81%

  2. The leading edge spars. (11 votes [25.58%])

    Percentage of vote: 25.58%

  3. liek who carez LOL (8 votes [18.60%])

    Percentage of vote: 18.60%

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#21 Harrier

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Posted 21 January 2009 - 10:19 AM

"If anybody ever tells you anything about an aeroplane "or kite" which is so bloody complicated you can't understand it, take it from me: it's all balls.
R. J. Mitchell.

#22 kairusan

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Posted 21 January 2009 - 12:57 PM

......(huge amount of well-reasoned analysis)......

So, the contradiction. JB is quite right in the conclusion he draws from his empirical experience. The verticals are under much more compressive stress. And because compressive load is totally destructive if the rods get out of column, and because something as simple as flying the kite forwards can get the rods out of column, they are the rods most likely to break IMHO. But John M is also right in that the LE is under the most stress from the moment of inertia (That is the bending force talked about above - strictly the cylindrical area moment of inertia, but that is splitting hairs!). By design the rods are very able to cope with this stress so long as there are no faults such as in improperly assembled LE to contend with.

And the answer to the OPs question is both the LE and the verticals are under more stress than the other - it is just different stresses in each case. So I voted for both!


Wow, what a wonderful analysis! I suppose, then, based on Sailor99's information, and JB's and others' arguments from experience, the best way to put together a "hybrid" frame for use in squirrely wind conditions (aha! The sinister secret purpose behind my creation of this most kite-nerdiest of threads.... revealed!) would be to use a stronger center LE and verticals, and save weight in the LE end rods, as opposed to putting in an overall stronger LE and saving the weight in the verticals.

For it seems that when the Goddess of Gusts puffs up her cheeks and exhales a hurricane in the general direction of one's Rev, it is the center LE that's going to take most of the compression force from the overall LE's flexing, and meanwhile the poor, underappreciated verticals have to stand there and steadfastly endeavor to hold the sail together almost by themselves. And then when the Lord of Lulls takes over for his cruel mistress and sends some positively necrotic "winds" one's way, the lighter outer LE rods will aid the kite in its efforts to hang on to its place in the sky by its proverbial fingernails. Hence, one should always remember to hybridize horizontally!

Translation: lol thankx guyz, mistery solvd. k bai
kairusan

#23 Sailor99

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Posted 21 January 2009 - 02:03 PM

"If anybody ever tells you anything about an aeroplane "or kite" which is so bloody complicated you can't understand it, take it from me: it's all balls. ”
— R. J. Mitchell.

Are yes balls. The great man must have been referring to spherical volume moments of inertia. That is very complicated and difficult to understand, unlike area moments.

I am reminded of Sir Humphrey Appleby's retort to a politician who scrawled "ROUND OBJECTS" across one of Sir Humphry's recommendations: "Whom is ROUND, and to what does he object?" ;)
Over - Jeremy

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Knowledge: The small part of ignorance that we arrange and classify.

#24 jay

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Posted 22 January 2009 - 11:27 AM

Maybe usefull but who knows
the only time I have broken anything on the kites was with a Rev 1
4 wrap frame verticle spar snapped like a matchstick when a gust caught me offguard.
put 3wraps in verticals and carried on flying no problem maybe because the 3's have more flex in them it helped absorb the gusts more.
Tight Lines
Jade



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#25 jay

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Posted 22 January 2009 - 11:53 AM

After reading sailors reply again
I have come to the conclusion that if I dont want to break verticals
I should assemble the verticles on the front thus not allowing the sail to push the verticals out of column!
:devil:
Just a thought
Tight Lines
Jade



http://www.kiteworld.co.uk/

#26 Harrier

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Posted 23 January 2009 - 06:23 AM

"For it seems that when the Goddess of Gusts puffs up her cheeks and exhales a hurricane in the general direction of one's Rev, ....... And then when the Lord of Lulls takes over for his cruel mistress and sends some positively necrotic "winds" one's way."


Therein lies the answer to your op, enlightenment comes with the wind at your back and and a kite in the air, not looking at a VDU.
The loads imposed upon your kite come from you the flier, you can be as gentle or as harsh as you wish in stressing your frames, the answer is in your hands.

#27 Choccy

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Posted 23 January 2009 - 07:05 AM

enlightenment comes with the wind at your back and and a kite in the air, not looking at a VDU.

:clap;
1 of the 47.

#28 Wobbly

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Posted 23 January 2009 - 12:12 PM

When I 1st started flying Rev's I was very cautious about flying in strong wind's 8mph plus !! , I then had the good fortune to meet some experienced flyers who thought nothing of flying in wind's of 30mph + the more I flew with them the more confident I became the moral of this tale is
1) The more experience you have the strength of the wind becomes less of a problem
2) Rev's are probably stronger than you think
3) Thing's sometimes break because that is what things do
4) You don't have to pay to use COMMON SENSE it's one of the few thing's in life that is free

#29 Love2fly

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Posted 25 January 2009 - 07:13 PM

Hey John-
Sadly, I confirmed what you stated today about the downspars! During a gust and windshift at the same time, POP!!! It snapped almost in the center. bummer.... but you were right. There wasn't much, if any bow to the LE and without warning, voila!
Laura
 
*** Any day flying is a good day; have a great one! 
**** REVS: Fly it, you'll like it!
***** L.S.P. ... It's worth the trip!
 
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#30 RevWizard

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Posted 25 January 2009 - 07:25 PM

Hey John-
Sadly, I confirmed what you stated today about the downspars! During a gust and windshift at the same time, POP!!! It snapped almost in the center. bummer.... but you were right. There wasn't much, if any bow to the LE and without warning, voila!

My experience over 18 years flying REVs tells me:
If the rod made a loud pop like a gun going off then it most likely due to excess stress, however then the rod usually breaks in more then one place.
If it is a almost noiseless break and only in one place, this is usually the result of damage to the rod or in very rare cases a manufacturing defect.

Long John (formerly Mr. R)

STACK International Executive Committee - 6/1996-6/2008
International Rules Book Committee and STACK International Head Judge - 6/2004-6/2008
World Sport Kite Championship Judge - 2004-2005-2006(Chief Judge)
13x 1st - 12x 2nd - 6x 3rd places in 37 overall Quadline individual competitions


Web Site - http://www.johnnmitchell.com/index.html Check it out today!


#31 Love2fly

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Posted 25 January 2009 - 07:59 PM

The pop wasn't that loud and only broke in half....
It was very cold; if that had an effect....
I've used the frame for months, so no defects unless something happened to stress it earlier today.
Laura
 
*** Any day flying is a good day; have a great one! 
**** REVS: Fly it, you'll like it!
***** L.S.P. ... It's worth the trip!
 
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#32 Kitelife

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Posted 25 January 2009 - 08:05 PM

When I blow a vertical, it tends to sound like a .22 gunshot, and almost always breaks into 3-4 pieces.

John Barresi

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#33 Love2fly

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Posted 25 January 2009 - 08:11 PM

When I blow a vertical, it tends to sound like a .22 gunshot, and almost always breaks into 3-4 pieces.


Then what caused it? Some sort of minute fracture?
Laura
 
*** Any day flying is a good day; have a great one! 
**** REVS: Fly it, you'll like it!
***** L.S.P. ... It's worth the trip!
 
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#34 RevWizard

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Posted 25 January 2009 - 08:17 PM

The pop wasn't that loud and only broke in half....
It was very cold; if that had an effect....
I've used the frame for months, so no defects unless something happened to stress it earlier today.

This symptom appears to me, to be physical damage such as something hitting the rod like a trunk lid or maybe something dropped on it. This can even happen when the REV is packed up and in it's bag.

Long John (formerly Mr. R)

STACK International Executive Committee - 6/1996-6/2008
International Rules Book Committee and STACK International Head Judge - 6/2004-6/2008
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#35 RevWizard

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Posted 25 January 2009 - 08:23 PM

This symptom appears to me, to be physical damage such as something hitting the rod like a trunk lid or maybe something dropped on it. This can even happen when the REV is packed up and in it's bag.

The odds are you won't even be able to see damage to the rod, even if you look hard at it. However if you drop the rods horizontally and individually on a concrete floor, you might be able to detect a damaged rod by the sound of it hitting the concrete.

Long John (formerly Mr. R)

STACK International Executive Committee - 6/1996-6/2008
International Rules Book Committee and STACK International Head Judge - 6/2004-6/2008
World Sport Kite Championship Judge - 2004-2005-2006(Chief Judge)
13x 1st - 12x 2nd - 6x 3rd places in 37 overall Quadline individual competitions


Web Site - http://www.johnnmitchell.com/index.html Check it out today!


#36 Love2fly

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Posted 25 January 2009 - 08:47 PM

It most certainly wasn't hit by my trunk lid closing on it. My kite bag goes in the same spot, carefully, with several kites/frames in it, which I suppose would add to the overall strength or integrity of the bag.
The temperature was 20 degrees; with a rogue gust over 10 mph.
Do you think that could have had any effect on it? I honestly don't remember any collisions or strange hard landings. ... interesting... no biggy, overall, just curious!
Laura
 
*** Any day flying is a good day; have a great one! 
**** REVS: Fly it, you'll like it!
***** L.S.P. ... It's worth the trip!
 
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#37 RevWizard

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Posted 25 January 2009 - 09:00 PM

It most certainly wasn't hit by my trunk lid closing on it. My kite bag goes in the same spot, carefully, with several kites/frames in it, which I suppose would add to the overall strength or integrity of the bag.
The temperature was 20 degrees; with a rogue gust over 10 mph.
Do you think that could have had any effect on it? I honestly don't remember any collisions or strange hard landings. ... interesting... no biggy, overall, just curious!

The same happened to me years ago at a competition in Cervia. The rod, which I had used for years in reasonably strong wind popped in mild wind with hardly any sound and broke in one place. I was very sure it must have been some physical damage, probably in transit. I have zero idea when or where to this date.

Long John (formerly Mr. R)

STACK International Executive Committee - 6/1996-6/2008
International Rules Book Committee and STACK International Head Judge - 6/2004-6/2008
World Sport Kite Championship Judge - 2004-2005-2006(Chief Judge)
13x 1st - 12x 2nd - 6x 3rd places in 37 overall Quadline individual competitions


Web Site - http://www.johnnmitchell.com/index.html Check it out today!


#38 Love2fly

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Posted 25 January 2009 - 09:35 PM

The same happened to me years ago at a competition in Cervia. The rod, which I had used for years in reasonably strong wind popped in mild wind with hardly any sound and broke in one place. I was very sure it must have been some physical damage, probably in transit. I have zero idea when or where to this date.


Thanks.
It's all good... chalk it up to the learning curve... I guess!
Laura
 
*** Any day flying is a good day; have a great one! 
**** REVS: Fly it, you'll like it!
***** L.S.P. ... It's worth the trip!
 
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#39 Kitelife

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Posted 25 January 2009 - 10:27 PM

Then what caused it? Some sort of minute fracture?

Nope, full on wind pressure, center of the window.

John Barresi

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(found in a fortune cookie - possibly an Einstein quote)

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#40 Choccy

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Posted 26 January 2009 - 01:03 AM

This symptom appears to me, to be physical damage such as something hitting the rod like a trunk lid or maybe something dropped on it.
This can even happen when the REV is packed up and in it's bag.

How about a large dog bounding over and standing right on top of your revbag, would that cause any potential damage ? :huh:
1 of the 47.




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