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Registered Member #194
Joined: Fri Feb 17 2006, 07:52PM
Location:
Posts: 19
I'm sorry aahz I wasn't trying to ignore you. I didn't think we'd have any follow up questions here.
You've pretty much listed the major points. The significant difference is the energy usage. We had a huge capacitor bank but we only used a few tens of joules at a time as opposed to the 2kj dumps that our competitors attempt. It's extremely wasteful to just full-charge and dump.
We didn't look at the capacitors as "capacitors". We looked at them as a power supply capable of delivering several thousands amps with a minimal voltage drop. (If you have enough of them)
Now, the smaller your capacitance (keeping I constant) the larger your voltage drop on the bank. And vice versa. We were attempting to create the ideal low-esr constant voltage supply.
And yes, you will have problems with a Chrony indoors if you don't have the light fixtures for it.
FYI: Just to pour salt in any wounds....when we finished the project in December 05' we were at 22% Efficient tossing a 133gram armature about 100fps with the 6 stage TTF design. It's a good thing we graduated or someone would be dead.
Registered Member #158
Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282
The sportsman guide I beleive is surpluss type stock and varies and unfortunately doesnt look like they have any chronos right now. As far as indoors I know there will be problems, thats why they sell light fixtures for some of them - but I should have asked if anyone has just tried to use thier own lighting (fixtures I have seen were like $30-40!). Seems like FastMHz did this succesfuly with common lamps... has anyone else? Anyone else have any sources for new units much less that $100?
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Chronographs to measure projectile speed?
