PSA for pinching off struts

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PSA for pinching off struts

I've had 2 "incidents" recently, the most recent being this weekend. The first was a faulty or broken elbow on one of the struts of a new kite. This weekend the valve on the leading edge of my Rebel literally blew up/off while on the water. The leading edge filled up with water. Fortunately I wasn't too far out, wind was onshore, and I was kiting with a buddy. Still, it was difficult swimming the kite in. No ability to self rescue in the traditional sense as essentially the kite became a sea anchor. If I didn't have the struts pinched off it would have been near impossible to make any ground getting the kite to shore. There must be reasons for not doing it but I've been surprised by the number of folks I've observed or say they don't do this. Curious what those reasons are but regardless I'm going to continue to do so!

Pics of the damge for those curious. Valve completely ripped off.  

My reason is really stupid

I want to get on the water faster :(

I might be completely wrong

I might be completely wrong on that, but I tend to leave them open to have pressure from impact distributed more evenly. I closed them a few times and had my deflate valve pop after tomahawking the kite.

 

 

Similar Issue with Cabrinha Strut Valve

@ Toby, I think you actually increase the pressure at the leading edge during a tomahawk by leaving your strut valvues open. The air inside of the struts (a fluid) will rush to the leading edge during a straight on impact. Its like all the the crap in your car hitting the windshield duirng a head on collision. This is all negligible as the mass of air is so low and the cross section of the interconnecting tubes are also small. Cool thought though. 

@Duxkiter, My strut valve blew out after a crash at hood river and i had not pinched off any of the other strut valvues. The kite completely deflated but fortunatley did not fill up with water. It was a very long swim (maybe an hour) although plenty of jet skis asked if I needed help (Nice instructors out there) I waved them off as it was a duable swim and they were on the clock. I now pinch off two struts in case one fails.

Now if I could only remeber to insert my donkey dick after teather self launching I would be a happy man. 

 

I believe pinching struts is

I believe pinching struts is important, but I often forget to do it.

Dunoyerfilms.com

Strongly agree to ALWAYS do

Strongly agree to ALWAYS do this... one of the strut tubes blew out on me with a newish RPM a couple years ago.  Kite went down like a sad duck.  Didn't fill with water but would have been like an anchor and damn hard to swim with.  I was very lucky it was low tide at FE and could just walk it out otherwise may have had to write the kite (and maybe bar) off. 

Always pinch my struts. I

Always pinch my struts. I have had a strut go during a session before and was able to continue riding , no problem. If my struts were open session would have been over, and I would have had a long swim with a limp kite.

The clips are there for a

The clips are there for a reason...just saying.

I agree with perk175 comment

I agree with perk175 comment that un-pinched helps abosrb the pressure and given a few people suggest my knickname is "kitehammer" I dont pinch them usually to help my leading edge absorb. That said if I am going to a downwinder, offshore, or a situation that I may need the floatation in emergency I would and do regulary in that case.

At all my regular kite spots with safe wind directions I generally do not. I might do one if the condtions concern me just in case as a float. Its a good read that a strut or strut connection deflates the kite. Could have finished the session had you pinched them but I still dont bother for that. Most all of this is laziness especially when packing a kite to knot have a wingtip trapping air.

If you don't pinch them and need the flotation. Self rescue your kite an blow air in to it. Or if you lost the kite dont forget you can blow air into your suit and trap it so you don't have to tread so much. Can blow air into any clothes should you fall in water. Take of jeans blow in air and save your life. Maybe good info maybe excuse to not alway pinch struts.

DIstributing the load

The theory that not pinching off the struts helps with distributing the impact of a kite hammer is one that is not likely to be proven out in actual practice.  If you think about the surface area and volume of the leading edge relative the additional surface area and volume of the struts you might think that having the struts not pinched off would be a big benefit. On a 5 strut kite, those 5 struts might be 25% of the total air volume and 35% of the surface area of the system.  The surface area is the area over which the shock can be absorbed by stretching and the volume is space over which it is distributed by a uniform increase in overall pressure.  The benefits of the additional area and volume offer are likely to be small because the shock is not likely to be transmitted to the struts quickly enough to matter because the hoses connecting the leading edge bladder to the strut bladders are narrow and air has some viscosity. If you want to get a feel for this, pump your kite up to 4 or so PSI without the hoses pinched, squeeze and hold one of your strut bladders in one hand and step on the leading edge bladder. You will notice that you can't feel the pressure increase in the strut.  Now do the same holding the end of the leading edge bladder.  Here you will notice the difference.

In addition, pinching off the connections issolates your points of failure.  A leading edge bladder with 5 struts has 6 bladders, 5 hoses and 10 connections that may fail. Lets not forget the reason we want to section them off.

Tom Brady could have used you

Tom Brady could have used you during Inflategate.

Nice breakdown Peter! I smell

Nice breakdown Peter! I smell a masskiting myth busters spinoff.

3 out of my 4 kites don't

3 out of my 4 kites don't have a clip to pinch the struts hoses, but I try to close at least one strut on that one kite that has it, at least when I remember.

Guillaume

Well no wonder my kites

Well no wonder my kites always fail the kitehammer regardless... Well then back to lazy excuse then :-)

Just an FYI- This happened to a previously repaired Kite

Just an FYI-  This happened to a previously repaired Kite and not a stock out of the box. 

The Valve and a good section of the leading edge bladder had been replaced...