Was having a nice afternoon on the water today when I messed up a transition and tomahawked my kite in to the water, not too hard or anything. When I got it back in the air it quickly deflated in to a jellyfish and I had to rescue. It was a LF Solo and the centre strut held.
I got the back to shore and pumped it up and it seemed fine, held air for 15 minutes at 9 PSI. Couldn't hear any leaks.
I had to fully deflate the kite during rescue so I didn't get a chance to check the valve. I don't screw on my outer valve very tight though and it was still attached when I was packing up in the water. The old school valve didn't pop either.
So I'm not sure how the kite so rapidly lost pressure, I'm thinking the tomahawk forced the inner flap through the hole and the air leaked out through the loosely screwed on outer cap. Trouble is I don't think it could lose pressure that fast.
I wiggled the one-pump hose a bit because some of my old kite have cracked one-pump hoses or valves that hold air at a certain angle but will leak if you bend it. Didn't hear any leak.
Did you pull up the flap before inflating?
Sometimes it takes more effort to pull it back up.
If it's stuck inside the valve it could lose air through te cap with a hard impact.
When you unscrewed the cap with the rescue did it lose air straight away?
I've had this happen to me a couple of times, usually when it happens I can hear air hissing from the main valve. Tapping on the tongue re-seals it and it seems fine.
I'm not really sure how to prevent it from happening -- I've started giving the tongue a few taps to make sure it has a tight seal, and the only times I've had it leak are when I *don't* do this, but I don't know if there's any correlation there.
It happens infrequently enough (maybe 3 times in a little over 3 years of owning LF kites) that I don't really worry about it
I'm also riding LF kites since 2013 and it never happened to me.
What i do is when i'm rolling up the kite i push the flap completely in the valve.
(all gentle of course)
When i start inflating i always pull the flap back up.
Not always the pressure brings back the flap in position.
Then you could lose air through the cap.