I managed to float a couple of 1200 and 1500 gram balloons by putting a PVC pipe with an end cap in the neck of the balloon and drilling a 1/16" hole in the end cap (two 1/16" holes were too much as

I suggest reaching out to Michael K5NOT (ARBONET) who did the presentation at GPSL 2010. Another investigator was James Flaten with his students at the University of Minnesota who shared their results

I searched my Gmail archive and there are fragments of a discussion on this topic based on an ARBONET balloon flight in the summer of 2010 which may have measured this. There may even have been a

Thanks for looking. I assume the data was consistent with the data you shared. Dennis

I remember the data that matched mine, was the actual flying flight. There was a small but very detectable spike just before burst. And when I did the tensile

The x axis is time. It was just a relatively constant fill rate.

Jerry, what do the numbers along the x-axis mean?

Correct. I also did a test during a flight but couldn't find the data. Jerry

Jerry, Thanks for the data. Pretty small differential. I assume that the graph shows the differential pressure vs time during which you added gas to the balloon at a more or less constant rate. Is

I did some experiments on the differential pressure on a balloon This was a ground test on a fairly small latex balloon (100 Grams I believe) but larger ones would be similar. As you approach burst

I did have these numbers, But it was a long time ago. The numbers I got I did it by testing a piece of the envelope it's tensile strength, and doing the tons of math to

I am curious. Many of us have measured the atmospheric pressure versus altitude. I have wanted to, but haven't, measured the pressure inside the latex balloon as it rises. Has anyone measured the

It was a 1500 Kaymont balloon. Knowing the pressure differential is extremely low. When I tested the ping pong ball, I know it leaked badly. The texture of the ball just

Joe, please tell us more. Latex or other envelope? How did it work out for you? Any special reason for trying this valve method out? What altitude was reached? How long did it remain in the

I ran into that with a tank from oxarc, entire s cyl and it didn't lift off the ground and by the calculations we did the s cyl should of been a couple of extra cubic feet. It was great that a fellow

Caution: I have encountered at least two industrial gas suppliers that offer lower cost 'balloon grade helium' which is not 99% or better helium.(!) It is 30%-40% nitrogen. The thought and

You can get a good estimate of the purity of a gas by calculating the lift per unit volume. The typical "balloon helium" we get here in the UK is about 95-97% pure (the remaining 3 - 5%

I think helium from virtually any industrial gas supplier, even if labeled "balloon grade", is at least 99% purity, and often balloon grade is 99.99%. Five nines is decent for most all industrial

My payload went up at a slower rate that I had forecasted last time and I know I just got kind of lazy and sloppy. But even with me adding weight to the payload and not accounting for it the helium

Looking at the cross section dimensioned drawing and the photograph, it's pretty certain the tetroon was filled through an internally threaded port. After removing the fill tube from the port, the