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Registered Member #6534
Joined: Sat Sept 08 2012, 12:22PM
Location: The Netherlands
Posts: 32
Cewl! What do you want to make the grip out of? I would think metal isn't the best choise (Risk of short-circuiting/shocks and all.) so do you want to go for plastic? Wood maybe? Looks interesting so far!
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
Yep, it's very impressive. It's not the driving voltage that transfers power to the projectile, but rather the voltage that the projectile induces in the rails or coils that matters.
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
I just got back from vacation, I'm going to try and start soldering that circuit board I posted. Unfortunately it will be a while before any more test shots since there's a lot of work left to do and I don't have much free time these days.
Sounds good to me - I've just reached 37m/s recently but have to go back and rebuild everything due to a barrel flaw, so I'm not that ready to compete yet. :) BTW, believe it or not, but I've reached 20% of efficiency from 3 out of 4 stages of my accelerator due to recuperation. As my projectile is 6.57gram, you still beat me by kinetic energy, so my goal is to reach higher speed. ;)
Registered Member #1525
Joined: Mon Jun 09 2008, 12:16AM
Location: America
Posts: 294
Yandersen wrote ...
Sounds good to me - I've just reached 37m/s recently but have to go back and rebuild everything due to a barrel flaw, so I'm not that ready to compete yet. :) BTW, believe it or not, but I've reached 20% of efficiency from 3 out of 4 stages of my accelerator due to recuperation. As my projectile is 6.57gram, you still beat me by kinetic energy, so my goal is to reach higher speed. ;)
Wow 20%? Nice job Yanderman. I would love to see PE/KE/velocity/efficiency data for each stage. And of course a video of things being shot.
Anyways, as promised, here's the power conditioning circuit board. It accepts 25V and 50V from the two six-cell LiPo batteries and efficiently steps down the voltage via two LM2594 buck converters to 15V for all the control circuitry and 3V for the laser targeter. It also contains a low-voltage battery alarm for each battery, which lights a red LED once the batteries drop below 18.3V (below 18V six-cell LiPo packs can experience cell damage). I think I did a nice job considering all the components I crammed onto one little board, and I only burnt my finger once while soldering it together!
As I told you, your quality mezmerizing me - because I couldn't do it same good. Here is my monster in a first attachment. Mention short coils and projectile of 12mm in length and 9.4mm in diameter. So far 3 stages and 2 out of 4 caps used, and 37m/s is achieved. Specially for you I've finished a beer to shoot the fresh can - see what 37m/s does to it in the second attached picture. And here is a chart of a result showing the performance of each stage in a third attachment. I'm working on a third stage right now, and the fact that it's efficiency is lower than the one of the second stage is a result of a bad timing, probably, which is controlled only by coil inductances, as there are no controller - each stage shoots right after previous one is done. It's my easy solution and mini-secret - I wouldn't tell you how it's done by now, but very simple and guessable by a given picture. :)
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New Coilgun Project
