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hybrid peaks test.

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
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Unread postAuthor: D_Hall » Tue Jun 10, 2008 7:32 pm

jimmy101 wrote:
D_Hall wrote:And then there's the issue of recording their output at sufficiently high data rates to actually make use of their output....and that's even more expensive than the gauge.

Naaah. Dig up a retired PC, like an old Win98 box. You now have all the hardware, and most of the software, to record the transducer output at more than adequate sample rates. Two channels, 16-bit resolution per channel, ~44,000 samples/second.


I'm happy to be corrected but....

I'm not aware of you having recorded actual pressure readings from a pressure transducer. Your own page indicates the piezo-electric transducers you use indicate pressure rate of change (1st derrivative of pressure), but that's a far cry from pressure.
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Unread postAuthor: SpudFarm » Wed Jun 11, 2008 10:52 am

i may do that but i will use a small chamber of 2" hydraulic fittings and higher mixes (21x)
that is when i get my money. that is not that easy on my age but i got $60 to tear a phone book in half :D

mabe i can try to walk around and ask people for jobs in the vacation.
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Unread postAuthor: jimmy101 » Wed Jun 11, 2008 12:18 pm

D_Hall wrote:
jimmy101 wrote:
D_Hall wrote:And then there's the issue of recording their output at sufficiently high data rates to actually make use of their output....and that's even more expensive than the gauge.

Naaah. Dig up a retired PC, like an old Win98 box. You now have all the hardware, and most of the software, to record the transducer output at more than adequate sample rates. Two channels, 16-bit resolution per channel, ~44,000 samples/second.


I'm happy to be corrected but....

I'm not aware of you having recorded actual pressure readings from a pressure transducer. Your own page indicates the piezo-electric transducers you use indicate pressure rate of change (1st derrivative of pressure), but that's a far cry from pressure.

Agreed 100% but that wasn't my point. The AD converter and data recorder in a sound card is more than adequate for the data accquistion. The transducer is a different matter. IF you had a suitable transducer and, if needed an amplifier, then the soundcard would be more than adequate to digitize and record the signal.

In other words "And then there's the issue of recording their output at sufficiently high data rates to actually make use of their output....and that's even more expensive than the gauge. " Is what I was disagreeing with. A PC soundcard has sufficient sample rate for this application. A 50mS combustion time would give 2400 data points. That should be more than adequate.
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