Page 2 of 3

Posted: Sat Jun 26, 2010 7:30 am
by chinnerz
wow is that audio playing at 2kbs??

But that is an EPIC launcher you have there

Posted: Sat Jun 26, 2010 12:41 pm
by Moonbogg
Will the force pushing your bolt back be safe? The bolt better be super secure.

Posted: Sat Jun 26, 2010 4:43 pm
by Hotwired
That's some great machining and fabrication.

On the one hand I'd like to do something heavily machined and covered with o-rings myself but on the other, I have no real workspace or tooling so I'd probably have to pay someone to do it.

Another excuse I can use for not making another cannon anyway :P
Davidvaini wrote:"really nice looking cannon, but who knows if it works since there is no video"
threads.
I've got one of those.... I'll get round to a video someday though :wink:

Posted: Sat Jun 26, 2010 11:54 pm
by frocksie
The bolt is very strong. And the frame that retains the bolt is strong as well. I have no concerns whatsoever about the bolt or frame breaking.

Also, the pressure acting on the bolt will never be very high, as the golfball in the barrel starts moving at 3 psi, so the pressure acting on the bolt is far lower than the maximum chamber pressure immediately after ignition.

Posted: Sun Jun 27, 2010 2:45 am
by Moonbogg
frocksie wrote:The bolt is very strong. And the frame that retains the bolt is strong as well. I have no concerns whatsoever about the bolt or frame breaking.

Also, the pressure acting on the bolt will never be very high, as the golfball in the barrel starts moving at 3 psi, so the pressure acting on the bolt is far lower than the maximum chamber pressure immediately after ignition.
So the high pressure is used for velocity purposes rather than a need to push hard, right? I mean, if one could find a gas with a faster expansion rate but with less energy, it could send the gofball just as fast, right? Like, if a 4x combustion shot expands at the same velocity as a 10x, then wouldn't a 4x be just about as fast with a light projectile? I think that may also be where a longer barrel comes into play. It gives the extra gas volume more time to accelerate the projectile. You see where I am a little confused? What benefits did HGDT show you for 10x vs something like 4x for a golf ball?

Posted: Sun Jun 27, 2010 5:13 am
by SpudBlaster15
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras nec placerat erat. Vivamus dapibus egestas nunc, at eleifend neque. Suspendisse potenti. Sed dictum lacus eu nisl pretium vehicula. Ut faucibus hendrerit nisi. Integer ultricies orci eu ultrices malesuada. Fusce id mauris risus. Suspendisse finibus ligula et nisl rutrum efficitur. Vestibulum posuere erat pellentesque ornare venenatis. Integer commodo fermentum tortor in pharetra. Proin scelerisque consectetur posuere. Vestibulum molestie augue ac nibh feugiat scelerisque. Sed aliquet a nunc in mattis.

Posted: Mon Jun 28, 2010 11:10 am
by ramses
That audio compression is horrible.

Nice cannon!

How are you securing the two tubes to the gas transfer spacer thing? Are the O-Rings on those tubes?

Posted: Tue Jun 29, 2010 6:58 pm
by frocksie
How are you securing the two tubes to the gas transfer spacer thing? Are the O-Rings on those tubes?
No, the o-rings are only on the endcaps and the piston. The spacer is clamped in place with six bolts and sealed with bike innertube gaskets. This is able to seal because the contours of the spacer very closely match the contours of the barrel and spacer. Also, the rubber gaskets increase the friction between the barrel, spacer, and chamber, helping to hold the cannon together.

Posted: Fri Oct 08, 2010 8:03 pm
by Gun Freak
Where's that video? :P

Posted: Sat Oct 09, 2010 1:47 am
by Moonbogg
Yeah, I was looking forward to seeing this thing. Any progress?

Posted: Sat Oct 09, 2010 11:32 am
by frocksie
I hope to get a video up sometime in the next two months, but my camera is broken and I'm currently upgrading the ignition system.

The camera flash igntion coil circuit has been giving me problems so I think I will build a <a href="http://en.wikipedia.org/wiki/Wimshurst_ ... >Wimshurst machine</a> and use that as an ignition system.

Posted: Sun Apr 24, 2011 4:34 pm
by zeigs spud
dangg that thing looks like it takes namesss. nice craftsmenship it looks pro.

Posted: Sun Apr 24, 2011 8:43 pm
by Hotwired
frocksie wrote:The camera flash igntion coil circuit has been giving me problems so I think I will build a <a href="http://en.wikipedia.org/wiki/Wimshurst_ ... >Wimshurst machine</a> and use that as an ignition system.
Sounds like a hindrance.

What's not working with the ignition coil system.

Posted: Mon Apr 25, 2011 5:23 am
by Tobin
Thats a really nice cannon, looking forward to se some videos!

Posted: Mon Apr 25, 2011 2:13 pm
by frocksie
What's not working with the ignition coil system.
My coil had a short in it so it wasn't producing consistent sparks. When it did spark, the sparks were weak, too weak to ignite higher mixes.
Sounds like a hindrance.
Sure it's not the most compact system out there, but it's pretty cool and I have always wanted to build one. Also, I needed a project for tech class, and a Wimshurst fit the bill.

The Wimshurst is nearly done; all I have to do is finish the control system and motor assembly. Hopefully I'll be able to finish it in the next three weeks.