Long weekend report...
I went out to FAR on Friday night and stayed till 5PM on Sunday.
John from Microcosm was out at the site and brought out the first completed tank to come from the microcosm/unreasonable joint development effort. With peroxide it has a mass ratio of 36,
(I earlier said 40, but I messed up the correction for peroxide density) and theoretical burst of 600psi and expected burst of around 500. So far its only been hydroed to 180 or so.
This weekend I only ran one experiment, I launched a Novatel OEMV-1HV high vibration GPS on my little HPR rocket. It was the first GPS flight on that rocket that held lock for most of the flight.
From ignition to touch down it lost less than 3 seconds of data. It lost data when the nose cone/parachute ejection charge fired, and it lost data when the nose landed on the ground and rolled around. The GPS is in the nose cone, so getting slammed with a hard ejection charge data loss is not unexpected. The GPS only data can be found
here:http://www.rasdoc.com/data/GPS9_11_11.txt
The GPS can do 20 fixes a second, but I was more interested in seeing if it kept lock so I turned it down to 5 samples a sec to reduce data size for this flight. I also sampled the analog devices IMU at 50Hz during the same flight, so if you want the data set including values from the IMU ask and I'll upload that as well. The GPS is an expensive part $1245 or so. It can be ordered without the COCOM limits for non-export usage, for another $1K or so.
Other than my one flight and the SDSU fireing.
(here: http://www.youtube.com/watch?v=zzFeqNtMftM)
The other FAR experimental projects were all plagued by Murphy.
Two projects failed to make any flames at all, and the Sugarshot test had a spectacular night time cato. Later this week look for some spectacular youtube video when they post their results.
Nature even got in on the act with some awesome thunder and lightning.
John from Microcosm was out at the site and brought out the first completed tank to come from the microcosm/unreasonable joint development effort. With peroxide it has a mass ratio of 36,
(I earlier said 40, but I messed up the correction for peroxide density) and theoretical burst of 600psi and expected burst of around 500. So far its only been hydroed to 180 or so.
This weekend I only ran one experiment, I launched a Novatel OEMV-1HV high vibration GPS on my little HPR rocket. It was the first GPS flight on that rocket that held lock for most of the flight.
From ignition to touch down it lost less than 3 seconds of data. It lost data when the nose cone/parachute ejection charge fired, and it lost data when the nose landed on the ground and rolled around. The GPS is in the nose cone, so getting slammed with a hard ejection charge data loss is not unexpected. The GPS only data can be found
here:http://www.rasdoc.com/data/GPS9_11_11.txt
The GPS can do 20 fixes a second, but I was more interested in seeing if it kept lock so I turned it down to 5 samples a sec to reduce data size for this flight. I also sampled the analog devices IMU at 50Hz during the same flight, so if you want the data set including values from the IMU ask and I'll upload that as well. The GPS is an expensive part $1245 or so. It can be ordered without the COCOM limits for non-export usage, for another $1K or so.
Other than my one flight and the SDSU fireing.
(here: http://www.youtube.com/watch?v=zzFeqNtMftM)
The other FAR experimental projects were all plagued by Murphy.
Two projects failed to make any flames at all, and the Sugarshot test had a spectacular night time cato. Later this week look for some spectacular youtube video when they post their results.
Nature even got in on the act with some awesome thunder and lightning.
posted by Paul Breed at 7:53 PM
23 Comments:
Paul,
What is the tank over wrap?
Reuben
Color says Kevlar.
Its kevlar.
Thanks Paul.
Reuben
"With peroxide it has a mass ratio of 36"
I'm sure Paul already knows this, but for other people's reference the same figure of merit for the off the shelf pentair water tanks (same pressure rating) is about 10.
Rocket stage performance is proportional to Ln(mass ratio)
Assuming 1/2 the weight is in tanks... and 1/2 is other stuff then
The new tanks give 1.7 times the delta V as the pentair tanks.
Enough difference to easily remove a stage from a leo launcher.
Paul,
Thanks for all your help on the SDSU static test. I'm looking forward to seeing your peroxide tank integrated into a rocket.
--- Carl
And the circled areas on the tank, are they flaws in the Kevlar?
This was the very first tank we made by a 100% new process. The liner had two very tiny pinholes. The circles are around the pinholes.
These were fixed with resin.
....Don't carry a pressurized container by the valve stem.....There is a risk that it'll burst when you next fill it.
It needs a either a carrying handle or a cradle from now on if it's going in a rocket at full pressure.
The tank is so light that without some residual pressure it would be very fragile.
Its currently sitting at about 20 psi.
In the picture John is holding it by the sturdiest part.
Since this particular piece is being destroyed in a hydro test to burst next week, I'm not to worried.
Paul - will you try a carbon version next?
I don't believe carbon fibers are compatible with peroxide. Can someone confirm this?
The mass ratio looks more like 230:1. If you're talking about the tank, that's another matter.
Boy, you've come a long way from drink bottles and string! :)
http://unreasonablerocket.blogspot.com/2006_12_01_archive.html
Wow. You're almost at five years now. The progress is simply *incredible*.
Microcosm my partner on the tank development already has some unbelievable carbon tanks. What we are trying to build is a peroxide compatible tanks.
(http://www.scorpius.com/Documents/Pressurmaxx-Sapphire_Marcus.pdf)
Neither carbon fiber or epoxy is peroxide compatible. We are not using either.
Our stretch goal is to get tanks as good as the ones listed in the PDF above, with peroxide compatible materials.
http://www.scorpius.com/Documents/Pressurmaxx-Sapphire_Marcus.pdf
Could a carbon fiber skin over the kevlar main body add substantial strength, and would that prevent the peroxide corrosion of the fibers?
I looked at the Scorpius 53" dia, 170" long tank rated at 500psi (SF=2)to see what's possible for tank mass fraction with HTP (1.45gm/cc for 100%). Value obtained was 74:1 (Liquid weight:tank weight). Smaller tanks approaching half this or better are impressive.
For upper stages we want lighter, not stronger. Its already strong enough. So adding carbon on the outside would make it stronger, but not lighter.
I also don't want a tank where a leaky fuling fitting causes the vehicle to catch fire and or do other bad things. So If possible I want all structure to be compatible materials.
So if burst is at 500 psi. What pressure would you operate it at? 250 psi?
Wow, there is a great deal of useful data above!
Dude you must be carefull whith this ind of experiments because a mistake could destroy your life... I hope you get all preventions of case.
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