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"In the world of spuds today"

A place to ask general spud cannon related questions.
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Unread postAuthor: Jared Haehnel » Wed Mar 12, 2008 3:08 pm

If anyone still cares about it, I'm doing very well with the Range Calculator, managing to iron out a few more slight niggles. Anyway, I'm off to go write some more code - maybe then I'll be able to release the Beta.


I think we all are axniosly awiating its realese
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My current projects....

Currently buying part for...
http://www.spudfiles.com/forums/my-new- ... rt,15.html
Still on the drawing board...
C02 tank hybrid
Screen doors for submarines...
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Unread postAuthor: Ragnarok » Wed Mar 12, 2008 6:51 pm

ALIHISGREAT wrote:as long as it doesn't contain viruses

It won't - if I wanted to fill people's PCs with viruses, then there are much less convoluted ways of doing it than joining a specialist forum, making over a thousand posts, then writing a rather specific program.

Anyway, I took a short break from the actual code to work on the Excel user interface:
Image

Not yet done, I still need to put in more work, but it should give you an idea of the different variables that it's going to take into account, and some of the outputs. Not all of them are hooked up yet - for example "Flight path length" needs work.

The main algorithm needs a little more polishing, then after that I'll be putting in some time on the extra tools.
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Does that thing kinda look like a big cat to you?
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Unread postAuthor: daberno123 » Wed Mar 12, 2008 9:12 pm

Wow Rag,it looks very clean and easy to use.

Looking forward to trying it out, can't wait until its finished. :)
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Unread postAuthor: bigbob12345 » Wed Mar 12, 2008 9:19 pm

In the world of spuds today I got all the materials for my 6mm chamber combustion. I will try to put it together and get it working tomorrow(its getting dark outside and the light in my garage is broken).
And its looking good rag :thumbright:

Edit:I was just reading over the 5th page of this tread and realised a question from DYI that I never answered.
DYI wrote:And bigbob, what do you plan on using as a pressure source for this 220ci high pressure cannon that you're thinking of building? Because I don't think I'd be able to afford to feed the SCTBDC without a job, at $2.70/shot for gas alone


I will be using dry ice as I can get it for free.
It looks like this actually might get built as I saved up a little bit of money and have loads of stuff im going to sell on ebay this weekend.

God I keep changing my mind. I mentioned a super powerful hybrid launcher that I have plans for that I was saving up for but I got rid of that idea.
And then I was going to build a semi auto but then I realized I don't have the tools or time. uuh when am I going to make up my mind on my big impressive project(that is what I am calling it because I plan for it to be big and impressive.
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Unread postAuthor: SpudBlaster15 » Wed Mar 12, 2008 11:59 pm

Bigbob, I am often in similar situations, unable to decide upon an avenue to pursue. Currently, I am trying to decide upon whether I should continue spudding (not much that really interests me that I haven't built already), or get back into high explosives and pyrotechnics. Right now, I am leaning towards the latter.
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Unread postAuthor: jimmy101 » Thu Mar 13, 2008 11:57 am

Ragnarok wrote:Anyway, I took a short break from the actual code to work on the Excel user interface:
Image

Not yet done, I still need to put in more work, but it should give you an idea of the different variables that it's going to take into account, and some of the outputs. Not all of them are hooked up yet - for example "Flight path length" needs work.

The main algorithm needs a little more polishing, then after that I'll be putting in some time on the extra tools.

Ragnarok:

It would be real handy if the interface had buttons that would auto-fill the relevant cells (Diameter, mass, Cd) for standard ammo types. For example, T-balls, G-balls, 2" half-spud, 1.5" whole spud, BBs ...

A "reset" button is also very handy for any system with as many input varriables as this calculator has.
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Unread postAuthor: Ragnarok » Thu Mar 13, 2008 6:39 pm

jimmy101 wrote:It would be real handy if the interface had buttons that would auto-fill the relevant cells (Diameter, mass, Cd) for standard ammo types. For example, T-balls, G-balls, 2" half-spud, 1.5" whole spud, BBs ...

A "reset" button is also very handy for any system with as many input variables as this calculator has.

Already working on an auto fill tool. It's got all the basic things I can think of: Golf balls, baseballs, ping pong balls, tennis balls, 12g CO2 cartridges, batteries of different sizes, approximations for both .177 and .22 airgun pellets... and anything else that comes to mind.

As for BBs, there are so many varieties it's hard to know where to start - plastic in nearly infinite numbers of densities (from 0.12g up to 0.43g last I knew), copper, lead, steel, all of those in both .177 and 6mm sizes. Then add on 1/4", 3/8", 1/2", 3/4" and 1" steel ball bearings, and all the various sizes of buckshot and birdshot...
Suddenly the data table is an utter mess - I can think of at least 40 different spherical BBs and shot.

I don't know whether it would be better instead to put in a calculator for working out the mass of a standard sphere or cylinder based on it's dimensions and density (of course, there would be a table of densities for lots of different materials, and theoretically a table of shot sizes).

Spuds are also tricky. They come in lots of lengths and densities, with odd shapes that make it hard to know a drag co-efficent. My best guess remains at 0.5-0.6 for that, but it very much depends on how they're cut, and for all I know it could be more again.
Any thoughts on that matter?

A reset button is a good idea, and one I hadn't thought of - I'll add one.
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Unread postAuthor: bigbob12345 » Thu Mar 13, 2008 7:01 pm

Well today I finally made up my mind for my big impressive project. Don't expect it for another couple months(and yes there is a reason i didn't mention what it is yet.

In the world of spuds today I was inspired by spudchuckers full auto piston valve topic to take out my full auto piston valve that I started a couple months ago that is almost exsactly the same as the one suggested in the topic and got frustrated with. The problem I had is the pop off valve only acuated at 115psi(some may have different opening pressures) and would only let out a tiny shrivel of air before it was 115psi again and resealed. I might have to put orings on the piston to get it to open, we'll see. I didn't accomplish much other than making a new tighter fitting piston that will hopefully open when the pop-off triggers.

I also decided to stop saving up money for my big impressive project and use the money to build two guns this weekend. The first one will be a pvc burst disk mortar(155ci, 10ft golfball barrel, triggered burst disk setup)yes it is quite long but I have become very fond of long barrels, they offer more power and less noise at the same time but conveinency cripples as well as portability. the second will be a small marble shooting high pressure steel gun(25ci chamber,4ft by 1/2in pvc barrel, and a union).
And that is it.
sorry for adding lots of useless info to this post.

Edit: I have been having problems dowloading GGDT but I decided to try one more time 1hr ago and with a lot tinkering i finally got it to work.
I have been having so much fun calculating the performance of all my launcher and possible designs.
And I also fixed all the spelling errors in the above post.
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Last edited by bigbob12345 on Thu Mar 13, 2008 7:56 pm, edited 2 times in total.
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Unread postAuthor: POLAND_SPUD » Thu Mar 13, 2008 7:01 pm

rag I think that it would be really great if you could add a simple Cd calculator to this.... Cd is just way too important for ballistics... it's possibly the least known variable for all of us
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Unread postAuthor: elitesniper » Thu Mar 13, 2008 8:25 pm

In the worlds of spuds, i have made up my mind on what to build next, a 15 foot long galv steel chamber, 30 foot 1.5 gb barrel, and a 2'' union, operated on 200+ of pressures on regulated co2. :)
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Last edited by elitesniper on Thu Mar 13, 2008 8:30 pm, edited 1 time in total.
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Unread postAuthor: bigbob12345 » Thu Mar 13, 2008 8:27 pm

One word.
Overkill
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Unread postAuthor: elitesniper » Thu Mar 13, 2008 8:35 pm

Actually, the cb ratio should be .828:1 witch isnt much of an over kill, just a very large cannon :)
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Unread postAuthor: daberno123 » Thu Mar 13, 2008 8:40 pm

Bigbob, for your auto piston project try putting the pop-off on top of another pilot valve (QEV etc) instead of having it be the main pilot. It should dump more air and (hopefully) fully pilot the piston.

Good luck on all the stuff you're going to build, being able to use GGDT sure helps, doesn't it?
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Unread postAuthor: bigbob12345 » Thu Mar 13, 2008 8:40 pm

elitesniper:Okay well before you didnt put in the length of the golf ball barrel. I was assuming 20ft but 30ft is even better.
Well 30ft is still overkill.
but overkill is not a bad thing, hell Im putting a 50ft marble barrel on the kamg so I can penatrate 1/4in steel like DYI did and break the SOS.

edit: daberno thank you so much for that idea i will be sure to try that this weekend.
And yes GGDT does help a lot I have discovered that with a 50ft 6mm barrel on the PG I can break 2500fps, no typo.
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Unread postAuthor: iknowmy3tables » Thu Mar 13, 2008 9:12 pm

cool launch program, only if there were a chamber pressure variable.
I made a basic distance finding launch program for my ti-83 calculator it doesn't include air resistance because thats the only equation they taught me in precalculus,

big bob I think you could lower the relief valve's pressure by maybe puting a spring between the pull ring and base to add tension to pull on the pop valve a little
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