13 replies to this topic

[TAiLsChaser]

I read that some people have been having problems with streamlines and what not. Apparently, they have been fishtailling. I haven't used my PS2 in a while so I set up the targets from the disc shot to different ranges and angles to test its accuracy. Even though the darts are their normal streamline stability, they did not hit the little targets with all to great of accuracy. Amazed that perhaps that I, too, had been stuck by this phenomena, I got on SpaceCAD and tinkered with different designs.

I know from making rockets that fins are the mainstay for the stability of the rocket. Well... fins are kinda hard to put on a dart as they go in a barrel. But seeing how I have a single-shot gun that has a barrel I stick the darts in the end of anyways, why not put little fins on the tip. It should have some improvement. And it does.



In that picture, I used four little fins but I ended up only making three. Ignore the square at the end of the dart. I forgot to delete it before I uploaded the picture.

All in all, this is the first dart to have a POSITIVE stability rating. It sits at an awesome 0.16 calipers. Granted it's not too awesome but it's better than the short proper stefan (-0.37 calipers) I showed in my last post.





Flies like a dream and all that power doesn't go to waste now. What's the point of having something that can go the distance if it can't hit what it's supposed to?

Edited by TAiLsChaser, 30 December 2007 - 12:23 AM.

[hierarchy]

I'm not getting the pics.

[Omega]

Hmm. Seems like it might be outlawed in rounds for protruding edges, and it can't be in deep-barreled guns, nor do those fins look stable...

But damn. That's cool.

[TAiLsChaser]

Yeah sorry about the pics. Geocities is crap.... Apparently I "exceeded" the data transfer. Looks like I'm doing the Imageshack thing. I'll upload in a bit.

Edited by TAiLsChaser, 30 December 2007 - 12:05 AM.

[CaptainSlug]

All you need for stability in such lightweight projectiles are
1. Significant front weighting so that the lighter rear section of the dart is self-stabilizing.
2. A uniform aerodynamic profile on the front of the dart.

Streamlines fail both criteria. You can remedy them a good deal by simply using scissor to trim the hollow dome off of the tip. But if you want real accuracy I have yet to try anything comparable to my felt+washer stefans. And better still they're very easy to make.

Edited by CaptainSlug, 30 December 2007 - 12:02 AM.

[TAiLsChaser]

All you need for stability in such lightweight projectiles are
1. Significant front weighting so that the lighter rear section of the dart is self-stabilizing.
2. A uniform aerodynamic profile on the front of the dart.

Streamlines fail both criteria. You can remedy them a good deal by simply using scissor to trim the hollow dome off of the tip. But if you want real accuracy I have yet to try anything comparable to my felt+washer stefans. And better still they're very easy to make.

Yeah that's all true but there's only so much weight you can add until it doesn't make a difference anymore.
My fins do add a complexity to the dart however they are highly stable. It's like a gun. Some guns are situational; so is the ammo. Granted that without the fins, these darts fly ok but sometimes, you want better than ok just for kicks and giggles... and because you have nothing else better to do for a few minutes.

Edited by TAiLsChaser, 30 December 2007 - 12:20 AM.

[shoeshine5]

They are nice in concept, but I think the edges of the fins, and the high weight would be a safety issue.

[sn1per]

They look really cool, too.

[DeceitfulSteve]

The word is "caliber" not "caliper."

Also, doesn't the stability rating only really apply to a powered rocket?

PS - the fins are cute.

[TAiLsChaser]

The word is "caliber" not "caliper."

Also, doesn't the stability rating only really apply to a powered rocket?

PS - the fins are cute.

No, it's definitely caliper. Why would the program have misspellings? It's not dictating it as a "round."

The powering of a rocket is the same as though a dart were propelled out by CO2. The darts were made without any engines for SpaceCAD to take into account so its stability is based off of its design.

[M30]

Also:
Caliber is a measure of essentially the gauge, how "thick" a round is, right? Or the barrel? I can't remember.

Why would the same word be used to measure stability, which is what the program was estimating?
(Though a quick search of the web turned up no other uses of that word as something which measures stability, I'm willing to give you, TAiLsChaser, the benefit of the doubt.)

[DeceitfulSteve]

I haven't downloaded the software so maybe they've changed the spelling, but in this screenshot it clearly says caliber. Here's the first result on Google for rocket stability caliber. Also there are five times as many results for rocket stability caliber as there are for rocket stability caliper.

In this case, 1 caliber is equal to the diameter of the rocket, or whatever. Caliber is a measure of diameter. One may use calipers to measure the caliber.

[penguin807]

May I sugest that we keep the word as caliper regardless? Some people don't even know what the word caliber means, and having two words that are spelt the same would do nothing but confuse the crap outta people.

P.S. This was all written on my psp, so you better have like made out with your moniter when you were reading my post or something...

Edited by penguin807, 31 December 2007 - 02:55 PM.

[bobafan]

P.S. This was all written on my psp, so you better have like made out with your moniter when you were reading my post or something...

I've done that a couple times and forever,

I don't think these darts add any more accuracy than you can get from having the right barrel.