Ultimate Aerodynamic Shape?

14115 Views 31 Replies 11 Participants Last post by cjb4u, Jan 6, 2013

NightKnight

Discussion Starter · Dec 18, 2012

I have been thinking about the shape of the darts. It seems that most tail cones are angled at around 45 degrees and have inverted backs. It would seem as if darts of this design base their accuracy on symmetrical drag across the surface of, and directly behind, the tail cone. Is there a design that would increase accuracy and decrease drag? As an example, I wonder how a rounded back would do on a dart. It would decrease the drag, and would probably decrease drag related deceleration netting a higher target impact speed. I also wonder if the tail cone were longer, and perhaps used an increasing radius curve with stabilizing fins would also reduce drag while maintaining accuracy. Here is what I had in mind:

Yellow Amber Wood Rectangle Flooring

There would be at 4-6 fins of that type around the dart tail.

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1 - 20 of 32 Posts

NaturalFork

· #2 · Dec 19, 2012

Seems like it would work awesome!

cjb4u

· #3 · Dec 19, 2012

Well I think you should make a bunch in .625 and I will try them out for you. LOL I think the making of such a end would be above the average person and need a mold manufacturing process.

NightKnight

Discussion Starter · #4 · Dec 19, 2012

I know how to get them made, but it would be quite expensive in low-volume runs. Too bad I'm not rich. LOL

superman365

· #5 · Dec 19, 2012

my belief is that with a rounded back.....The dart would be aerodynamic against the air pushing it out of the tube resulting in a less powerful "launch". What do you others think?

I do believe a long cone would help though

NightKnight

Discussion Starter · #6 · Dec 19, 2012

superman365 said:
my belief is that with a rounded back.....The dart would be aerodynamic against the air pushing it out of the tube resulting in a less powerful "launch". What do you others think?

I would like to see what others think too. My thought was that the back shape would not change the in-tube speed because the speed comes from the pressure inside, and the pressure is maintained by the seal against the tube not the shape. Could be wrong though.

NaturalFork

· #7 · Dec 19, 2012

The in tube speed wouldnt change as long as it had a good seal.

NightKnight

Discussion Starter · #8 · Dec 19, 2012

You know, you could do the tail rounding by placing a marble of the appropriate size in the tail cone. Of course, I don't know what that would do to accuracy without the fins.

NaturalFork

· #9 · Dec 19, 2012

AaronC said:
You know, you could do the tail rounding by placing a marble of the appropriate size in the tail cone. Of course, I don't know what that would do to accuracy without the fins.

I know that Nico has told me he makes darts by simply putting a bead from the craft store on the end of a skewer. He has take a few birds with this method. So I am sure the marble might work. Might be kinda heavy though.

NightKnight

Discussion Starter · #10 · Dec 19, 2012

NaturalFork said:
I know that Nico has told me he makes darts by simply putting a bead from the craft store on the end of a skewer. He has take a few birds with this method. So I am sure the marble might work. Might be kinda heavy though.

Interesting. Are the beads round?

Yeah, I thought about the weight. I wonder how much project weight changes affects in-tube speed...

superman365

· #11 · Dec 19, 2012

with all that weight in the back with a marble....I'm pretty sure the dart would flip mid-flight and end up hitting the cone rather than the point...kinda like turtles first darts

NaturalFork

· #12 · Dec 20, 2012

AaronC said:
NaturalFork said:

I know that Nico has told me he makes darts by simply putting a bead from the craft store on the end of a skewer. He has take a few birds with this method. So I am sure the marble might work. Might be kinda heavy though.

Click to expand...

Interesting. Are the beads round?

Yeah, I thought about the weight. I wonder how much project weight changes affects in-tube speed...

Yep he used round beads.

NightKnight

Discussion Starter · #13 · Dec 20, 2012

superman365 said:
with all that weight in the back with a marble....I'm pretty sure the dart would flip mid-flight and end up hitting the cone rather than the point...kinda like turtles first darts

Burn....

Lightgeoduck

· #14 · Dec 20, 2012

I am not sure about the effects of a round rear end, but I do believe the cone is the perfect shape... the degree of the angle would effect the projection so the narrower the cone the longer it must be.. so figuring out the best cone maybe what is needed.... I think that is why paper cone darts work well. long and narrow means straight and fast.

a marble/bead at the end and fins is just a sense making a cone. as far as weight,,, I guess it would be like rubber and ammo for slingshots... the right weight for the size and pressure being applied... I recall the perfect balance for a dart is where the center of balance is just a tiny bit more than 50% of the darts length (towards the point).. I think I read somewhere 40% is the sweet spot.

LGD

Lightgeoduck

· #15 · Dec 20, 2012

sorry, one more thing would be interesting with your design is with the fins being slightly angled when attached to the shaft (right or left I mean) forming a spiral... giving the dart the same effects of a bullet in a rifled barrel...

LGD

superman365

· #16 · Dec 20, 2012

Lightgeoduck said:
sorry, one more thing would be interesting with your design is with the fins being slightly angled when attached to the shaft (right or left I mean) forming a spiral... giving the dart the same effects of a bullet in a rifled barrel...

LGD

that would be cool....another thing for me to try

NightKnight

Discussion Starter · #17 · Dec 20, 2012

Lightgeoduck said:
sorry, one more thing would be interesting with your design is with the fins being slightly angled when attached to the shaft (right or left I mean) forming a spiral... giving the dart the same effects of a bullet in a rifled barrel...

LGD

Yeah, that's a good idea!

treefork

· #18 · Dec 21, 2012

Does any one remember or heard of "Juavaro" blowgun company. They are out of business now but were big back in the 70's.They would advertise in the back of magazines. The point I'm getting to is they used a bead and wire dart which flew well. The .38 cal bead was light in comparison to the wire shaft. It works as long as the bead is light and the wire is heavy enough.

Cervantes

· #19 · Dec 22, 2012

AaronC said:
NaturalFork said:

I know that Nico has told me he makes darts by simply putting a bead from the craft store on the end of a skewer. He has take a few birds with this method. So I am sure the marble might work. Might be kinda heavy though.

Click to expand...

Interesting. Are the beads round?

Yeah, I thought about the weight. I wonder how much project weight changes affects in-tube speed...

I did the same, used some beads from Walmart hobby section. They work but the range (accuracy) is greatly reduced in my trials. I fired into my picket fence in the back yard and I saw the board shake on impact, good penetration, about 6mm. But that was at about 10 feet. Same ammo at 20 feet and my dart came out and immediatley turned int a sidewinder missle. Maybe the fins you mentioned would assist in stabilizing flight.

Turtle

· #20 · Dec 22, 2012

superman365 said:
with all that weight in the back with a marble....I'm pretty sure the dart would flip mid-flight and end up hitting the cone rather than the point...kinda like turtles first darts

Ya,

those d a m n wire nuts! I'll tell you though the duct tape cone works great!

1 - 20 of 32 Posts

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