"Offtopic-posts-topic" NSFW

[jsefcik]

Apprecaite it guys, I'm going to futher my education through the army considering its all paid for ,I do want to continue my plumbing nd heating, I already have a 3 yr degree on it nd
Want to contiue that but if I dont get that on my asvab scores , and as a back up id like to get combat engineer!!

[mark.f]

Apprecaite it guys, I'm going to futher my education through the army considering its all paid for , maybe ill become a liesnce gunsmith nd design hybrids then any otber spudder on the forum!!!


I want to do plumbing since I already have a 4 yr degree in it nd then move on

[jackssmirkingrevenge]

*chuckle*

[POLAND_SPUD]

look what I found on hackaday

http://hackaday.com/2013/02/04/shooting ... -mach-1-2/

[jackssmirkingrevenge]

Interesting, I remember we had discussed this: http://www.spudfiles.com/forums/mass-fl ... 16641.html

I'm guessing the fact that a ping-pong ball has extremely low density is somehow related.

[MrCrowley]

That arxiv paper is surprisingly basic, I'm sure there are more than a few members here who are capable of writing such a paper for a particular cannon. Though, our hypotheses are usually "I think I'll be able to shoot this through that given enough pressure"

[POLAND_SPUD]

I remember that thread and I shared it precisely because of that thread... maybe you're right JSR it's because of small mass

[jackssmirkingrevenge]

As I pointed out in the other thread, if there was any merit to the idea beyond firing extremely lightweight projectiles, we would see it more often.

I would surmise that the ping pong ball fired without the nozzle leaves the muzzle too quickly for enough pressure to build up behind it, so the advantage of the accelerated gasses is noticeable. If they tried the same setup shooting say golfballs instead I would expect the latter to have worse performance with the nozzle fitted.

[POLAND_SPUD]

lol not safe for work
[youtube][/youtube]

[btrettel]

I'm skeptical the convergent-divergent nozzle is necessarily helping here. They did no tests without it best I can tell. For all we know the gun would have performed better without it.

[jackssmirkingrevenge]

lol not safe for work

The whole series is brilliant:

Makes you realise what sentimental saps environmentalists are.



In the eternal words of Tim Minchin, so does cot death.

[wyz2285]

I'm thinking about buyingthese, and make a pneumatic launcher to use it. They're for 80 lb, I was wondering if I use too much pressure/muzzle speed will they fiy straight?

[PaperNinja]

my brother had something similar to those, they not only didn't fly straight, but the heads (maybe the tails? idk something) flew off whenever they hit the target. He got some solid-body plastic bolts similar to these that seemed to work a lot better (though they were a little heavier)

[wyz2285]

I thought about these but none ships to Portugal. Probably the tail, but I'm planning one remove the tail anyway so it would fit inside the barrel.

[Gippeto]

Wyz...arrows are drag/spin stabilized....you need the fletching.

Arrow shooting airguns use an arrow with the nock removed (the part that holds the string) and slide OVER a smaller diameter tube. The air comes through this smaller tube.

Kind of like blowing the paper cover off of a drinking straw.