Spar breaking points?

[relhak]

Does anyone (hey Revolution guys!) have any concrete data showing the breaking point of the various spars? How far can they bend before they snap?

I'm particularly interested in the Race Rods. Winds in Kansas City are quite variable, so I often find myself running the race rods to keep flying in winds of 8-12, but they can gust up to 20 in a flash. Now I haven't broken any, but the 30 degree-ish bend on the edge rods is rather shocking. And I like them a lot over the SLE, so I'm willing to take the risk of breaking them in a ground hit, but I don't want to snap them just flying across the window.

And for reference, plowing an unvented 1.5 SLE into the ground at a 45 degree angle in 30 mph winds WILL snap an edge spar.

[Morrunya]

If you are having problems with your Race Rod LE bending in that wind (wich is normal), I suggest getting a 3 wrap LE or just an entire 3 wrap set. You might even be able to go with 4 wrap. It should be perfectly fine flying with race rod down spars in that wind, but the le has a lot more stress.

You best choice would be to go with an entire 3 wrap set for that kite.

Do you get winds below that often??

Do you have a picture of the bend in the LE??

The Race Rods in a standerd 1.5 can take from 0- about 15mph.

[johnnmitchell]

Does anyone (hey Revolution guys!) have any concrete data showing the breaking point of the various spars? How far can they bend before they snap?

Nothing is openly available that I am aware of.

I'm particularly interested in the Race Rods. Winds in Kansas City are quite variable, so I often find myself running the race rods to keep flying in winds of 8-12, but they can gust up to 20 in a flash. Now I haven't broken any, but the 30 degree-ish bend on the edge rods is rather shocking. And I like them a lot over the SLE, so I'm willing to take the risk of breaking them in a ground hit, but I don't want to snap them just flying across the window.

As you can see from the attached picture, a REV can really bend the rods quite a bit. That particular REV was a REV I size specially built by me in Germany, where it is today, for stormy winds. I think the wind at that time was around 50MPH. The rods are original "Revolution Equipped" 4-wrap. Being a REV I, it is wider thus it can bend a greater total angle then a REV 1.5. A REV I rod is 91cm long. The REV 1.5 rod is 79 cm long.

And for reference, plowing an unvented 1.5 SLE into the ground at a 45 degree angle in 30 mph winds WILL snap an edge spar.

That is the weak point of graphite rods versus a fiberglass rod. They don't take blows so nicely. Otherwise they are by far superior in ever other aspect. The suggestion here is to refrain from flying in such strong winds until you have obtained excellent control of your REV, unless you enjoy paying for more new rods.

As Watty suggested, try using a complete 1/4" "UltraLight" 3-wrap frame.

You could also revert to the SLE rods which makes the LE stiffer and they are a bit tougher. For even stronger winds, "Revolution Equipped" 4-wrap frame is also available in 1/4" or SLE.

[Jim Foster]

I think I would be flying a vented sail. I would try sliding a two wrap leading edge set in along with the race rod leading edge. It will add a little bit of weight, but 8-10 mph should handle the extra weight just fine, and when those gusts come along, your kite won't fold up so much. Gusts can be difficult at times.

Just a thought, but you might give it a try.

Jim

[Mike]

My winds are the same here in downstate Illinois, and I agree with Jim: time to fly a vented. Even though the kite can handle that bend, you lose precision and control.

In low end of the wind range you listed, flying a vented with Race rods is pretty sweet.

When it picks up, I prefer to swap in 3 wrap spars, or even 4 wrap if you fly in winds that are consistently above 20. Or for mad fun in higher winds, get out the Rev II!

[relhak]

As you can see from the attached picture, a REV can really bend the rods quite a bit.

(rev 1, 4 wrap)

Good lord, that's a LOT of bowing. Maybe the theme of this thread should be "Post pics of your tortured Rev". I'll bring my camera next time I fly.

The suggestion here is to refrain from flying in such strong winds until you have obtained excellent control of your REV, unless you enjoy paying for more new rods.

I bought a vented 1.5 (plus the race frame) right after that. And I stopped flying in that park; it has lots of flat, treeless space, but it's surrounded by 50-100 foot hills covered in trees. The wind direction had a 90 degree variance and speeds mostly 10-20, but as much as 5-30. Several times I had the kite pulling well at 70-80 degrees elevation, only to roll forward and fall out of the sky. Immediately before I broke the spar, I had barely enough wind to maintain an inverted hover.

As Watty suggested, try using a complete 1/4" "UltraLight" 3-wrap frame.

Aren't the 1/4" 3-wraps the same strenth?

I think I would be flying a vented sail.

I'll give it a try. I never would have thought of that.

I would try sliding a two wrap leading edge set in along with the race rod leading edge.

I suppose it saves an ounce vs the 3 wrap SLE. Is there any advantage to the 2-wrap vs Race Rods other than cost?.. I'd prefer to just get a second Race Rod frameset. And do you have to add extra end caps, or do you just shove it in alongside?

To sum up the questions about 1/4" frames, do the 2&3-wrap frames have any advantages over the Race Rods other than costing about 25% less?

[johnnmitchell]

I bought a vented 1.5 (plus the race frame) right after that. And I stopped flying in that park; it has lots of flat, treeless space, but it's surrounded by 50-100 foot hills covered in trees. The wind direction had a 90 degree variance and speeds mostly 10-20, but as much as 5-30. Several times I had the kite pulling well at 70-80 degrees elevation, only to roll forward and fall out of the sky. Immediately before I broke the spar, I had barely enough wind to maintain an inverted hover.

I used to fly daily in a park where I sometimes experienced similar conditions. When the wind blew the length of the park it was okay. When the wind blew from either side it was usually quite strong. The kite, REV or dual line would shoot along like a rocket and hit a certain place and drop out of the air. This was very frustrating and aggravating.

The solution I came up with when I had this conditions, was to pack up my kites and go over to the beer garden and enjoy a nice beer.

[beach]

Hello Family and I've been watching this thread and wanted to add my thoughts on breaking rods, when rods break it can be for two reasons I think

1. being after a hit you have damaged the threads of graphite and created a weak spot (not visible most times)

2. to light of a rod for the wind or torgue your putting on it

Now lets go beyond this and talk about wing loading and the stress that this creates when you are flying. One thing that alot of people don't really understand is wing loading and how that relates to stress on both the leading edge and the verticals, wing loading is the amount of stress put on the wing relating to the wind against the sail, then the amount of strength that you apply to the handles & strings againt the force that the wind creates on the sail all of these and more = wing loading and power generation.

Now for even another twist in broken rods you have fliers such as John Barresi who because of how they fly they create huge amounts of torgue but in there defense they have ingrained in themselves how to dump the wind off of the sail at the right moment and this ability only comes after years of flying..........

I personally can go on for hours and explain it all but why what matters is that no matter what your going to break rods and as in everything else using graphite is a trade off because of weight, reflex, and strength, but the big thing is that it works and it works well, also seeing as were here and I've opened a huge can of worms. Please remember that the "race rod" program was more about reflex than weight or strenght, these rods were made for the way they rebound after being bent so many degrees rather than how much the weigh or how strong they are, sorry but true.....

Well that all for now but we'll talk more about this at a later date...........Ben

[Morrunya]

Aren't the 1/4" 3-wraps the same strenth?

What???? I'm not sure what you mean by this, but I'll answer the things that I think you might be asking.

No. 3-wraps are stronger than race rods.

"Ultralight" and "3-wrap" are the same thing

1/4" is the internal diameter, not the strength.

I suppose it saves an ounce vs the 3 wrap SLE. Is there any advantage to the 2-wrap vs Race Rods other than cost?.. I'd prefer to just get a second Race Rod frameset. And do you have to add extra end caps, or do you just shove it in alongside?

1. No. 2 wrap is inferior to race rods in flex, strength, and weight.

2. You do not need to add extra end caps. The friction of the main LE will hold the extra LE in place.

To sum up the questions about 1/4" frames, do the 2&3-wrap frames have any advantages over the Race Rods other than costing about 25% less?

Once again, no. 2-wrap is heavier and weaker that race rods. But 3 wrap does have one advantage if you are not lacking wind....... it is stronger. 3-wrap is heavier and stronger that race rods.

*unrelated, but something that I just noticed, why is my forum ranking Watty?????? I don't want to jack a thread or anything, so if someone has the answer, could you just PM me?? I'm confused.*

[big bri]

Thanks guys ,thers some real good info here on spars.I have been accused of being over cautious at times with my choice of spars,but hey.I cant EVER remember breaking one.

Wattys info is as near as you will get and with JM ,Jims, and Bens input ,etc,etc,you wont get better help or info anywhere.

The secret of my Spar Choice is,when in any doubt.I get a thicker wrapped rod OUT.

Easy if youve a load of spars to swop and change,which is quite a usual thing,or i swop to a kite i know has the spars i need,or std to vented, or even as someone said, a Rev more akin to higher winds or lower if ther isnt a wind.Again,i have the luxury of haveing a few Revs.Im a LUCKY guy.

Thanks chaps.Great Topic and Info.

BRIAN...ps,50mph JM, with a rev 1,that must have been one Hell of a days flying.I bet your arms are six foot long now John.Great info btw.

[Morrunya]

An easy way to choose the rods that you will use, is that is your kite is pulling unusually hard, or seems to be flexing more than normal, put in some stronger rods. The wind will be strong enough to hold up the next size of rods. After a while of flying and choosing rods, you can pretty much always chosse your rods immediatly based on how strong the wind feels on you skin. By now I'm able to wak outside and immediatly know wether to use a vented or standard kite, and what rods to use with that kite.